|Year : 2019 | Volume
| Issue : 1 | Page : 4-36
Recent Concepts in Nutritional Therapy in Critically Ill Burn Patients
Department of Hand Surgery, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, India
|Date of Web Publication||30-Apr-2019|
Department of Hand Surgery, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai-600116
Source of Support: None, Conflict of Interest: None
| Abstract|| |
In developing countries such as India, burn injury is still a major and frequent cause of mortality and morbidity. Nutrition therapy aims to provide adequate and early nutrition for patients suffering from burn injuries. Metabolic support during heightened inflammatory state is essential to make sure adequate treatment of burn patients. It is essential to reduce the force and effects of the hypermetabolic response, aim for healing of wounds, and help to reduce negative catabolism effects. At the same time, care of surgical and medical needs of the patient is crucial for good clinical outcomes. Nutritional sustain is an essential and integral component of burn care that requires an aggressive multifaceted approach. Impaired wound healing, dysfunction of multiple organs, increased chances of infection, and death are largely prevented by an adequate nutrition care along with proper wound management. Catecholamine and corticosteroids, inflammatory mediator levels, are increased, and this hypermetabolic response leads to catastrophic results in the postburn injury period. A shift from preventing malnutrition to disease modulation in nutrition support in critically ill patients is being aimed at present. Uncontrolled inflammation causes severe metabolic derangement in burn patients. Major challenges are assessment of nutritional status of the patient and estimation of nutrient requirements. Careful decision-making for safe use of enteral or parenteral nutrition and an aggressive nutrient delivery are required. The course of disease can be altered favorably to a great extent by supplementation of specific nutrients. Nutritional factors with positive effects on immunity and in cell regulation include glutamine, arginine, and essential fatty acids, known as immunonutrients. They reduce the severity of illness and improve response to treatment of patients. Nutrition support specialists are trying to improve the management protocols and technological advances such as nanotechnology and biomarkers will take the nutrition management to greater advances.
Keywords: Assessment, biomarkers, hypermetabolism, parenteral nutrition, pediatric burn nutrition, micronutrient, nanotechnology, substrates
|How to cite this article:|
Natarajan M. Recent Concepts in Nutritional Therapy in Critically Ill Burn Patients. Int J Nutr Pharmacol Neurol Dis 2019;9:4-36
|How to cite this URL:|
Natarajan M. Recent Concepts in Nutritional Therapy in Critically Ill Burn Patients. Int J Nutr Pharmacol Neurol Dis [serial online] 2019 [cited 2021 Feb 26];9:4-36. Available from: https://www.ijnpnd.com/text.asp?2019/9/1/4/257489
| Introduction|| |
In India, over an estimated 1,000,000 people sustain moderate-to-severe burn injuries every year. Annually, 7 million people with burn injuries require hospital admission of which 140,000 are fatal. The National Burns Program statistics show that 91,000 women sustain burn injuries. Children and women of child-bearing age are more likely to sustain burn injuries and mortality is 3 times more compared to men. Critically, ill burn patients pose a great treatment challenge to the attending intensivist. Burn injuries of minor nature can be treated on an outpatient basis. Less than 10% of the victims require hospitalization, and the proportion of patients requiring treatment in burn intensive care units (BICU) is less. During the last three decades, the burn care has improved tremendously with the availability of better antibiotics, nanotechnology-based dressing materials, and nutritional support. Developments in anesthesia techniques, advances in surgical modalities, and intensive burn care therapies have resulted in reduction of both mortality and in postburn sequelae. National Programme for Prevention and Management of Burn Injuries (NPPMBI) guidelines lay more emphasis on prevention of burn injuries. World Health Organization (WHO) has an estimated 180,000 deaths caused by burn injuries. Developing low- and middle-income countries contribute to nearly 95% of fatal fire-related burn injuries according to WHO fact sheet, 2018. Emphasis must focus on prevention of burn injuries, nutritional care, and rehabilitation. International Society for Burn Injuries (ISBI) and European Burn Association (EBA) are the major organizations in the field of burn injuries and research. Patients with major burns are considered as critically ill, and protocols of general intensive care units (ICU) care recommendations apply to such patients. Randomized and placebo-controlled human studies of high quality with large number of patients on major burn-specific issues have been investigated. GRADE rating in healthcare is a method of assessing the certainty in evidence and the strength of recommendations [Table 1].
|Table 1 Grade of recommendation, assessment, development, and evaluation|
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Nutritional supplementation is crucial in critically ill burn patient treatment protocols. Guidelines and protocols of nutritional therapy in critically sick persons in ICU are extended to the nutritional management of burn patients also. The challenges are more in patients with associated trauma, comorbidities, and complications such as inhalation injuries. The gross pathophysiological changes, altered fluid dynamics, metabolic, and electrolyte derangements are the challenges in management. In addition, infectious complications and the severity of burns largely influence the nutritional parameters and therapeutic interventions. Emerging trends are supported by the evolution of critical care services and evidence-based medical care protocols are supported by the emerging technological advances. This manuscript is aimed at discussing the important issues pertaining to the nutritional supplementation of patients with critical burn injuries and the recent technological advances in the field of nutrition sciences.
Chemical burn injuries occur in accidentally at chemical industries and at home. It is a sensitive social issue and needs a special mention. The most important cause of chemical injury is acid attack. Acid throwing (vitriolage) is a form of violent assault defined as the act of throwing acid or similar corrosive substance onto the body of another “with the intention to disfigure, maim, torture, or kill.” Acid attack is “crime of passion” as a result of jealousy or revenge, with intent to burn and damage skin of faces to cause permanent disfigurement. Sulfuric and nitric acids are the most commonly used acids. Hydrochloric acid is sometimes used, but is less damaging to tissues. Strong alkaline solutions of caustic soda (sodium hydroxide) are also used. Acid attacks happen all over the world, but this type of violence is most common in South Asia. According to Acid Survivors Trust International (ASTI), the UK has one of the highest rates of acid attacks per capita in the world. In 2016 there were more than 601 acid attacks in the UK based on ASTI figures. In India accurate statistics of chemical burn injuries are not available as many incidents go unreported for fear of retaliation. Acid Survivors Foundation India (ASFI) statistics show a clear increase in number of acid attacks every year with around 1000. Immediate first aid of chemical burn injuries include:
- Inform emergency medical services and poison control center
- Try to remove the chemical and contaminated clothing carefully, with all personal protection precautions
- Rinse the affected area with running clean water for 20 min
- Some acid burns may be made worse if rinsed (flushed) with water, namely, carbolic acid or phenol, sulphuric acid, and metal compounds
- Flush with large amounts of water to remove chemical from the eyes, to reduce chances of serious injury to the eyes
Pathophysiology: Most acids produce coagulation necrosis by denaturing proteins. The eschar formed prevents tissue penetration of acids. Bases produce liquefaction necrosis by denaturing proteins and, in addition, cause saponification of fats. This does not prevent tissue penetration and the tissue damage is more. Hydrofluoric acid produces liquefaction necrosis. The severity of burn depends on the pH of the chemical, concentration, duration of contact, volume, and physical form of the chemical. The amount of thermal and caustic injury caused by dilution also plays an important role in tissue destruction. There may be an associated ingestion of chemicals.
| Emergency Department Care of Patients|| |
- Complete removal of the chemical contamination with continued low pressure irrigation
- Measure pH using litmus paper
- Secure airway and fluid resuscitation are started
Treatment is continued as for a typical burn injury patient and wounds must be covered as early as possible as per the burn unit protocols. Hydrofluoric acid burn needs special mention as the fluoride ion penetrates through the skin. For small and superficial burns, topical calcium or magnesium gels are applied. For deeper burns, injection of calcium gluconate is used. For burns involving the hands, subcutaneous injection of calcium, intra-arterial calcium infusions, or intravenous infusions of magnesium are used. Consultations: Ophthalmologist consultation is a must for all chemical burns involving face. For suspected ingestion of chemicals, gastroenterologist, GI surgery, and ENT surgeon opinions must be followed. Children require management by a pediatric surgeon.
Chemical burn injuries have devastating effect on the social, economic, psychological, and morale of the affected person. Repeated reconstructive surgical procedures may be required. A long period of rehabilitation and psychological counseling are needed for the victims. Support from the family, governmental, and nongovernmental organizations are crucial in recovery of such unfortunate victims. Governmental legislations and education of general public will help in minimizing acid attacks in future.
| Socioeconomic Aspects of Severe Burn Injuries|| |
Management of burn injury is resource and time-intensive. Most patients require a long duration of hospital stay, and significant costs are involved. The socioeconomic burden of burn injury is very high. Medical expenses are a huge burden, and the personal and per capita income of the family is reduced significantly depending on severity of injury. Management of burn injuries involves huge part of the exchequer on part of the governments. This financial burden on the government is beyond the monetary budget of developing nations such as India. Corporate social responsibility, involvement of social service organizations, nongovernment organizations, and formation of burn patients support groups will be beneficial to the patients with burn injury.
| Hypermetabolic State in Burn Injuries|| |
Severe burn injury elicits physiologic response not only at the site of injury, but also alters the functions of various organs. The liver, heart, gastrointestinal tract, muscle, bone, and kidneys are the common organs affected. Altered metabolic functions mediated by a sharp rise in the serum levels of catecholamine, corticosteroids, and inflammatory cytokines persist for more than 2–3 years following severe burn injury. Hypercatabolism is characteristized by the following features in a patient with 25% burns: (1) metabolic rate in an adult patient is elevated to as high as 118%–210%. (2) Approximately 180% rise in resting metabolic rate. (3) Calorie need exceeds 5000 kcal/day. (4) The patient with 40% burn injury loses 25% of preadmission weight within 3 weeks time without nutritional support. (5) Impaired immunity and delayed wound healing. The stress response has an initial hypometabolic “ebb” phase (lasts from days to weeks) followed by hypermetabolic “flow” phase beginning at about the fifth postburn day and may persist up to 24 months. Lean body mass reduction, bone density alterations, and weakness of the muscles of stress response affect immune function and wound healing [Figure 1]. Burn injury has the highest metabolic response among critically ill trauma patients. Damaged tissues activate the inflammatory event that maintains the catabolic state. The high circulating levels of cytokines modify the basal metabolism of the body and keep it at a higher level for long periods after acute trauma.
|Figure 1 Hypermetabolic response is associated with severe burn injuries, trauma, and sepsis|
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As the resting energy expenditure (REE) reaches more than 10% above normal, the patient is in a hypermetabolic state. There is an increased consumption of whole-body oxygen. REE remains high between 40% and 100% above normal in acute postburn phase with greater than 40% total body surface area (TBSA) burn. Surgical and nonsurgical treatments implemented by the burn team effectively control the stress response. Wound excision and early skin cover is the most beneficial surgical modality. Nonsurgical methods available are adequate analgesia, administration of catecholamine antagonists, and anabolic hormone pharmacological therapy. Provision of adequate and early nutritional support is an important factor that determines the positive outcome in patients. Enteral nutrition (EN) support with adequate protein, carbohydrate, antioxidants, vitamins, minerals, and trace elements is essential for reverting the effects hypermetabolic changes.
Hypermetabolic response during postburn injury is mediated by cytokine cascade, catecholamine, and corticosteroids. The circulating serum levels are elevated by 10–20 times more in the postburn period and remain high for up to 12 months following burn injury. Elevated catabolic hormones result in insulin resistance, increased gluconeogenesis, energy consumption, lipolysis, and proteolysis. Gluconeogenesis-mediated high serum glucose level is not “protein sparing.” They may lead to poor “take” of graft, increased incidence of wound infection, morbidity, and mortality. The catastrophic metabolic changes have to be taken care of for better outcome of the patients. Pathophysiology of burn injuries is dynamically changing and complex. Nutrition and metabolism in burn patients are difficult to assess and treat during burn care. Different compositions of nutrition are required at different stages of the course of treatment. Variations in treatment methods and complex pathophysiology of individual response patients are the important factors. It may take long to standardize nutritional plan program in a burn center. Multi-institutional trials are difficult to implement because of differing nutritional support requirements in different individuals, and an optimal nutrition protocol has to be individual-based one. Physiological/biochemical markers are useful to assess potential benefits of nutrients, and evidence-based clinical trials will be beneficial in future.
Management of critically ill burn patients is extremely challenging to the attending burn care team. The catastrophic effects of prolonged hypercatabolism needs to be managed:
- Hypercatabolism leads to fatal cachexia with a weight loss of up to 40% of admission weight and increased rates of bone catabolism
- Children develop growth retardation, which may persist up to 1 year postinjury
- Lean body mass loss of 10% leads to immune dysfunction and loss of 20% leads to significant impairment of wound healing
Critical illness “stress response” to severe burn continues for a few years following injury. The pathophysiology of stress response is complex and difficult to contain. The WBC genome of burn patients remained changed for up to 1 year postburn. Burn-induced hypermetabolism is characterized by increased substrate turnover, cachexia, and poor clinical outcomes. Oxidative stress and systemic inflammatory response syndrome (SIRS) are characterized by:
- Formation of free radical.
- Cleavage of the nuclear factor kappa B (NF-κB) inhibitor. When the inhibitor is removed, NF-κB initiates mRNA, which induces production of other pro-inflammatory cytokines.
- IL-6 stimulates release of C-reactive protein (CRP) and procalcitonin.
- Infection releases more tumor necrosis factor-alpha (TNF-α) that stimulates more production of IL-6 and IL-8 that are responsible for high fever of infection.
- A shift from Th1 to Th2 cytokine response leads to an increase in Th2 antibody-mediated (humoral) immune responses.
- High mobility group box 1 (HMGB1) released passively by damaged cells results in SIRS.
- Inflammatory cascade amplification.
In SIRS, shift of vitamins and trace elements from circulation into tissues and organs occurs. They are utilized to enhance protein synthesis and production of immune cells. Trace elements, antioxidants, and water soluble vitamins are also used up in this process and are deficient. Antioxidants, vitamins, and trace element supplementation help to modulate this response.
Concerns in critically ill burn patients: A multidisciplinary approach is needed for management of burn patients. The challenges are:
- the gross altered pathophysiologic changes,
- altered fluid dynamics,
- vulnerability to infections,
- metabolic derangements,
- electrolyte disturbances, and
- influence of severity of burns on the nutritional parameters and therapeutic interventions.
Pathophysiology of altered metabolic state: Hyperdynamic circulatory state is seen with burn injuries greater than 40% TBSA. Increased levels of catecholamines, glucocorticoids, glucagon, and dopamine lead to catabolic state [Figure 2]. There is massive protein and lipid breakdown resulting in muscle wasting. Hyperglycemia occurs due to peripheral insulin resistance. The altered metabolic state begins within days of burn, which may persist for several years postburn. Associated inhalational injury leads to airway edema, fluid and electrolyte imbalances, thermoregulatory changes, and increased risk for infections. Ventilatory drive is decreased due to weakness of respiratory muscles. This leads to more ventilatory support days and increased hospital stay.
Various nutrients and drugs have impact on the reversal of the hypermetabolic state. Nutrition supplies important cell substrates and vital nutrients required for body metabolism. Morbidity and mortality increase as severe burn injury affects functions of other organs of the body. Early wound excision and skin cover is the key to reduce the mortality and morbidity. High protein and nutrient supplementation on an aggressive nutritional support basis is required in patients with burn injuries:
- elevated metabolic demands need to be meet,
- prevention of energy reserves and nitrogen stores depletion,
- to support good healing of wound,
- to boost immunity, and
- to improve survival rate of critically ill burn patients.
Important aspects in burn patients: Inhalation injury adds insult to the injury and patients may need respiratory assistance of lung protective mechanical ventilation similar to acute respiratory distress syndrome (ARDS). Damage to upper airway and presence of inhalation injury requires a high degree of suspicion to identify even in the absence of detectable oropharyngeal changes. The levels of combustion products such as carbon monoxide or cyanide in the blood may be elevated. Bronchoscopy demonstrates anatomic injury and is the “gold standard” for diagnosis. Increased fluid requirements are associated with inhalation injury and fluid allowances are added accordingly. Heparin inhalation has been identified to be effective in treatment of inhalation injuries. Dimethyl sulfoxide or N-acetylcysteine are free-radical scavenging agents with beneficial effects along with bronchodilators in treatment of inhalation injury. The primary aim of therapy is to prevent cast formation that may lead to small-airway obstruction. Lung injury in burn patients leads to ARDS due to reduced ventilation perfusion. Nitric oxide dilates blood vessels, increases perfusion of lung alveoli, and corrects the ventilation-perfusion mismatch.
Immunological response to burn injury: Infectious complications are significantly raised because of immunosuppression in burn patients. “Burn toxins” are associated with prolonged allograft survival and anergy that make burn patients more susceptibile to infections. Patients develop SIRS and sepsis. Multiple organ dysfunction syndrome causes morbidity and mortality as direct effects of complications. Inspite of recent advances in early care of burn patients, these complications still remain a challenge. Immune modulator treatment protocols may reduce these complications, and it may be possible in near future to overcome the challenges.
Pain management and sedation: Goal of burn care is adequate pain relief and priority must be given for pain relief along with other resuscitation measures. The severity of pain depends on the depth and total area of burn. The psychological trauma is associated with the frequency, the need for multiple procedures, and the fear of future. The cornerstone of critical burn care of today is the high-quality analgesia and sedation along with resuscitation., Burn patients require sedation and analgesia very frequently and have an increased risk of constipation. Diet rich in fiber content can avoid constipation.
Burn injury in obese patients: Obesity is considered a state of chronic inflammation.
Pro-inflammatory cytokines, including IL-6, TNF-α, and CRP levels, are high in obese patients. They are more susceptible to the increased inflammation and associated hypermetabolism. There is severe and rapid muscle wasting in the early postburn period. There is also severe insulin resistance in obese patients. Decreased bioavailability of vitamin D3 in burn patients may lead to vitamin D and calcium deficiency in such patients.
Wound healing in burn patients: Glucose is the preferred energy substrate for macrophages, leucocytes, and fibroblasts in the burn wound. Wound-generated lactate is converted back to glucose the liver. An increase in Cori cycle More Details has the advantage of energy production. Alteration in systemic pH due to lactate has bacteriostatic effect and stimulates collagen synthesis, which is beneficial for wound healing. Lactate induces collagen synthesis, vascular endothelial growth factor (VEGF) expression, and migration in endothelial cells through generation of superoxide. Plasma lactate is a good predictor marker of sepsis and mortality in burn patients. A serum level of 4 mmol/L provides the best sensitivity and specificity. Mortality in burns can be reduced by fluid resuscitation that normalizes plasma lactate levels, and it is a reliable prognostic marker of global tissue hypoxia. Exogenous glucose administration diminishes endogenous production by only about 50%. Burn patients have increased glucagon: insulin ratio and insulin resistance. Hyperglycemia associated with burns results in delayed healing, depressed immune activities, and exacerbation of protein catabolism.
Nutritional support of elderly burn patients: Elderly patients with extensive burn injuries are more susceptible to pronounced metabolic response. Nutritional support is required for balancing the enhanced energy expenditure and for survival of the patient. The acutely injured elderly patients must be supplemented with early, internal continuous nutritional support through nasogastric tube (NGT) for providing the extensive calorie requirements. This effectively prevents upper gastrointestinal tract ulcer formation and stress hemorrhage in the elderly patients and reduces frequency of complications related to sepsis. Basal energy expenditure (BEE) with incremental energy input is calculated based on body weight, and burn size is used to calculate nutritional requirement in the elderly patient with burn injuries. In the elderly population, it is important to assess preexisting protein-energy malnutrition and look for the presence of involuntary weight loss. Increased incidence of infections, poor healing properties, and mortality are the complications in such patients. Preexisting micronutrient deficiency states are also common in elderly patients and replacement therapy must be considered.
Criteria for critical burn injury: Infection and sepsis are still the biggest threats to survival from burn injuries especially in the developing countries. Burn wound sepsis and nosocomial pneumonia, including ventilator-associated pneumonia (VAP), are the common causes of mortality. Reactive oxygen species (ROS) are natural by-product of normal oxygen metabolism and play an important role in cell signaling and homeostasis. They have positive physiologic, metabolic, and immune changes in association with medical and nutrition therapy. Severe burns with fluid depletion, hemodynamic instability, airway problems, and patients requiring pain management are best treated in critical care units. Zaidi et al. in 1996 formulated the following criteria for admission to BICU:
- Burn injuries greater than 30% TBSA.
- Extremes of age: Younger and older age groups of patients are more susceptible to complications of burn injuries.
- Burn injuries associated with smoke inhalation.
- Burn injuries associated with high-voltage electric current.
- Burns patients with comorbid illness/conditions.
Treatment of critically ill patients of any cause is a great challenge. Severity of illness with unpredicted metabolic and physiological changes makes the treatment complex and sophisticated. The general principles of management of critically ill patients include:
- Early and adequate resuscitation to maintain an optimal blood volume is the priority. An adequate circulatory state must be maintained on a continuous process.
- Management of respiratory impairment and circulatory derangements are crucial for patient survival.
- Prevention of sepsis and treatment of infectious complications are important.
- Increased mortality is due to rapid development of malnutrition. Hence, early metabolic support is essential. Wound healing and tissue repair depend on an adequate enteral nutrition.
- Renal support with renal replacement therapy may be required in some patients. An extracorporeal continuous venovenous hemodiafiltration (CVVHDF) method is ideal.
- Psychosocial support for both the patient and their family help in early rehabilitation of burn victims. Adequate analgesia, treatment of anxiety, comfort, and dignity help in both the recovery and rehabilitation phases of burn injuries. The family needs access to information and support so that they can take care of the victims.
- Advantages of intensive care units include the presence of a highly skilled multidisciplinary team and specialized environment to identify problems and institute early, necessary treatment options.
The critical burn injury patients pose special additional challenges when compared with critical ill patients due to other causes. The unique challenges in critically ill burn patients are spread over a spectrum of variables. Pattern of complications is unpredictable with variable determinants of outcome. Resuscitation requirements and severe metabolic stress of burn injuries need to be addressed on priority basis. Hence, treatment modalities greatly differ from the management of critical patients of other causes. Early diagnosis of problems and immediate institution of specific therapy are required to minimize the mortality and morbidity.
Initial phase of fluid resuscitation: The Parkland formula has the advantages of being simple and easy to initiate and ideal for fluid therapy in the initial critical stage of resuscitation. The disadvantages of Parkland formula are that it is a high-volume resuscitation formula and patients receive greater fluid volume than predicted. A “Protocolized” Parkland formula was formulated due to doubts regarding accuracy and practicality of the formula. Initial fluid requirements, rate of administration, and hourly infusions are started as per Parkland formula. The fluids are adjusted according to the patient’s response and hourly urine output measurements. The protocol can be initiated by a highly trained specialized nursing personnel. Inadequate response to fluids, persistently high fluid requirements, and unstable vital signs in the patients during resuscitation need the intervention of the physician. Patients with symptoms of compartment syndrome and with increasing fluid requirements are modified to colloid replacement as per the “American Burn Association practice guidelines” for burn shock resuscitation. This Parkland Consensus formula for resuscitation calculates Ringer lactate solution for the first 24 h and is widely used by many burn centers at present: 4 mL/kg/% TBSA burned (“kg” is initial weight of the patient; “% TBSA” is the total of second and third degree burn injury). Half of the calculated fluid for 24 h is infused in the first 8 h. The remaining half is given over the next 16 h. The general guidelines for fluid resuscitation are as follows:
- Oral fluid resuscitation is sufficient for patients with burns <20% TBSA. Patients with normal gastrointestinal tract can tolerate large amounts of fluid. The patient must be under close observation and enteral resuscitation should be initiated as and when is necessary.
- Patients with associated comorbidities are ideally under invasive central hemodynamic monitoring, such as central venous catheters and pulmonary artery catheters. In patients with central monitors fluid administered and corresponding improvement in outcome do not correlate well. The treating team must be aware of the fact.
- Antioxidant therapy helps to reduce burn resuscitation fluid requirements and prevent formation of edema.
- “Fluid creep” is the most important problem during the initial phase of fluid resuscitation. Fluid creep is the requirement of more fluid than calculated by standard formulas and has serious edema-related complications. It may be due to lack or failure to add colloids in the resuscitation fluids used.
Fluid resuscitation has been improved with an incorporated computerized decision support system for patients with severe burn injuries: A fluid resuscitation pump along with a urine analysis monitor has been designed with a pulse oximeter, and a blood pressure monitor incorporated into a closed-loop medical device hardware platform. When connected to a ventilator, it optimizes fluid therapy. It records and communicates resuscitation data. This system calculates fluid therapy parameters and minimizes automation of caregiver tasks. It is simple enough to be operated by a minimally trained medic. The computer monitors the patient on a minute-by-minute basis with less chance for errors and complications due to under-resuscitation or fluid overload.
Principles of nutrition management in critically ill burn patient: The concept of hyperalimentation as the methodology of nutritional maintenance in critically ill patients has given way to a more pragmatic and restricted feed concept, guided by principles of evidence-based pritocols.
- Enteral nutrition is used whenever possible and is the most preferred route.
- If the gut is malfunctioning, parenteral nutrition is the choice for nutritional supplementation.
- Nutrition therapy reduces or blunt the effects of hypercatabolic state, which is a unique feature in critically ill patients.
- The caloric balance is maintained with 1500–2100 cal/day instead of the routinely practiced concept of providing excessive calories intake up to 3500–4500 cal/day.
- Early nutrition must be started as “proactive approach” in preventing starvation rather than treating it later on.
- Nutrition should be personalized for each patient taking into consideration the stage of burn care and condition of the wounds. Specific surgical and medical needs of the patient and current nutritional status of the patient must always be taken into consideration.
- Reassess adequacy of nutritional support for the patient and check for possible side effects on time-to-time basis.
Mortality prognostic scales in severe burns: Patients with critical burn injury have increased chances of survival due to the advances in development of intensive care management protocols. It has changed the understanding and concept of burn shock. Main factors that determine treatment outcome are the presence or absence of inhalation injury, preexisting malnutrition, acute renal failure, concomitant injuries and diseases, the presence of infection, and psychiatric disorders. Patients with extensive burns require multidisciplinary and multidirectional treatment. Multi-organ failure causes death in approximately 28% of burn patients. Acute Physiology and Chronic Health Evaluation II and sepsis-related organ failure assessment score are extensively used prognostic methods in critical care units.,
Burns evaluation and mortality (the BEAMS prognostic score) is modified from APACHE II scale. The BEAMS risk of death is an outcome tool for prediction for adult major burn injury patients admitted to ICU. It is an accurate and reliable mortality prediction tool. Burns-specific physiologic factors such as age and percentage of full thickness surface area of burn (%FTSA) are the main factors considered. Female sex and APACHE II are independent predictors of death among burn patients. A combination of Fatality by Longevity, Apache II score, and Measured Extent of Burn score (FLAME) is reliable predictive scale based on the APACHE II. Simplified acute physiology score (SAPS) is specific and accurate particularly in burns <40% TBSA. During the first 10 days the presence or absence of inhalation injury, extremes of age, and extent of burn injury are the main predictors of mortality. The other significant predictors (P < 0.05) include absolute monocytes count, lymphocyte count, maximum daily temperature (Tmax), and BUN.
Baux rule is a simple calculation in patients suffering from second and third degree burns. Baux score is expressed as: Baux score = % burn area + patient’s age. A score over 140 is considered as being unsurvivable. Revised Baux scale includes the presence of inhalation injury and is more promising as a prognostic marker in burn survival. Inhalation injury adds 17 points on the Baux score. Revised Baux scale = body area affected + age + 17.
Platelets play a significant primary and secondary hemostasis mechanism and also act as inflammatory cells. A significant low platelet level is noted in nonsurvivors of burn injury than in survivors. A rebound rise in platelets occurs in survivors in subsequent postburn days. Serial declining platelet count is a prognostic indicator of early burn septicemia, which indicates the need to modify treatment modalities. Correlating survival versus platelet aggregation against survival versus the revised Baux score is a prognostic indicator for survival following major burn injuries. Updated Charlson comorbidity index (CCI) is another prognostic study in relation to inpatient mortality.
Clinical effects of malnutrition in burn patients are varied with drastic effect on the overall physiological and clinical status of critically ill patients. They have specific and nonspecific effects on the health of the patient.
A. Specific effects [Table 2] of malnutrition include poor healing, wound dehiscence, breakdown of surgical anastomosis, poor immune response to infection, and failure of skin grafts.
B. Nonspecific effects:
- Lean muscle mass: Neoglucogenesis leads to substantial loss of muscle mass that leads to increased work of breathing. Such patients develop ventilator dependence, a challenging clinical situation to manage.
- Sepsis: Nutritional deprivation in the setting of sepsis can lead to multi-organ dysfunction syndrome. The liver and kidney are the most affected organs.
- Central nervous system is affected due to alteration in amino acid composition as a result of nutritional deprivation. Apathy, drowsiness, and inability to clear secretions are the common presentations.
Teamwork is a crucial component in patient care of a major burn injury. The integral components in all areas of patient management consists of patient education and treatment planning. Management of complications, control of infection, occupational health, and safety must be ensured as teamwork. Psychosocial care of patients and the families and continuous professional development are essential for final outcome of burn injury patients.
The burn team includes the following members: Anesthetists/pain management specialists, medical specialists, and intensivists are vital team members. Child life specialists/play therapists take part in management of children. Dietitians and diet technicians along with nutritionists and nutrition assistants are responsible for diet and nutritional aspects in burn patients. Nursing staff and indigenous health workers carry out the needs of the patients. Oral health specialists and dental health technicians are essential for maintaining the oral health. Occupational therapist, orthotists/prosthetists, physiotherapists, psychiatrists, psychologists, and mental health workers help in rehabilitation process of the patients. Social workers, pharmacists, rehabilitation specialists, and speech and language pathologist play a key role in patient care. Parents and family caregivers have a well-defined role in final outcome of the patient care. Recently, many American hospitals have included palliative care specialists in the healthcare team. Integration of primary and specialist palliative care in burn critical care program has potential benefits for the patient and their families.
Nutrient requirements in critical burn patients are markedly increased. Following major burn injuries, nutrient stores get repleted quickly and it affects various physiological and metabolic functions of the body.
- Patients with greater than 20% TBSA burn and patients in acute stress response should receive nutritional support
- Patients with lesser percentage of burn wounds but with preexisting malnutrition are candidates for nutritional support
- Patients with tuberculosis or HIV/AIDS need close monitoring and nutritional support must be added as and when required
Factors that influence nutritional requirements in burn injury patients are as follows:
- Age: Children, elderly, and teenagers are most vulnerable to the effects of burn injuries
- Pregnant and lactating women with burn injuries pose a challenge for nutritional support
- Nutritional status of the individual before the burn injury
- Diseases such as tuberculosis, HIV/AIDS, diabetes mellitus, and stress diabetes
- Renal failure and associated electrolyte disturbances
- Infection, sepsis, and associated fever
- Excessive humidity and environmental temperature changes
- Pain and anxiety increase in metabolic rate and they must be controlled effectively
“The art of clinical management” is an estimation of nutrient requirements and assessment of nutritional status of burn injury patients. Monitoring the response to feeding should also be done regularly and adequately. This requires the integration of science and various medical specialities for maximal benefit for the patient.
| Goals of nutritional support in critical burn patients include:|| |
- Lean body mass must be maintained
- Prevent starvation and avoid establishment of specific nutrient deficiencies
- Hasten good wound healing
- Prevention, control of infections, and management of established infections
- Visceral and somatic protein loss must be restored
- Enteral and parenteral nutrition-related complications must be prevented
- Stress response and complications must be attenuated or modulated with adequate and appropriate quantities of required nutrients
The nutrition plan must be coordinated from the time of admission to scar maturation based on the treatment and requirements at different stages. Consensus approach with other team members is ideal through consultations. The dietitian should implement nutrition plan with consideration for:
- Age, gender, and level of alertness of the patient
- Location and the status of wounds and skin replacement plans
- Physical status and preexisting nutritional status prior to injury
- Functional status of the gastrointestinal tract
- Lung function status and respiratory needs
- Pyrexia due to infections and other causes
- Pain management and sedation protocols followed in the particular unit
- Support of family and friends and psychosocial status of the patient
Individual patient factors are crucial for final outcome in patients following burn injury management. Compliance and individual priorities, cultural background, and religious beliefs are the key for optimal recovery. Preinjury behavioral problems, history of psychiatric or psychological illness, learning disabilities, or developmental delay has a profound effect on the final outcome. Reconstructive surgery-related psychological changes and previous experiences of hospitalization have a great role in the final outcome. Parents, caregivers, and family members responses alter the course of the therapy, and every effort must be taken to educate them throughout the treatment and rehabilitation process. Special dietary needs and food allergies need attention for better results.
Nutritional assessment in adult burn patients: Initial assessment of all patients with critical burn injuries is mandatory to form a baseline data for knowing the progress made throughout the therapy. Initial nutrition assessment should be made on admission to hospital and feeding must be initiated within the first 24–48 h of burn injury. Nutritional evaluation must be taken into consideration:
- Height and preburn weight of the patient are noted. Administration of fluid and edema alter the weight measurements
- Preburn nutrition history and current functional status of gastrointestinal tract
- Percentage of body surface of burn injury: sites of injury (around oral cavity and hands)
- Type and the level of pain control measures used
- Comorbid conditions or illness
- Usual diet of the patient, specific dietary needs, and associated food allergies
Identification of nutrition risk patients: Nutrition status is an ongoing dynamic process. The nutritional status in burn patients depends on the stage of injury and the treatment protocols. Malnourished patients have greatest risk for refeeding syndrome on initiation of nutrition support. Patients on nutritional rehabilitation before surgical treatment and prior to discharge have better final outcome results. Initial evaluation includes history related to number of postburn days, details of previous burn care, associated injuries, comorbid conditions, height, weight, and clinical examination assessment of patients. Nutritional risk factors include:
- Preexisting nutritional status
- Identify factors wherein the patient is not able to receive nutritions or not able to utilize nutrients he receives during stay in the hospital
- Age of the patient, severity of burn injury, associated inhalation injury, or organ dysfunction
Timing of nutritional support: Institution of early burn care treatment including nutritional support is crucial for patient outcome following severe burn injury. Ideally, EN initiated within 24 h of burn injury prevents development of malnutrition and depletion of nutrients. Following burn injury, there is increased bacterial translocation and decreased absorption of nutrients and lead to substantial intestinal mucosal damage. Early EN has distinct advantages and prevents the gastrointestinal complications.
- Catecholamine, cortisol, and glucagon circulating levels decrease
- Intestinal mucosal integrity is maintained as gut motility and blood flow are optimized and prevent development of curling’s ulcer
- Improves wound healing. Muscle mass is maintained
- Duration of stay in intensive care unit is made much shorter with nutritional support
Feeding through enteral route is started as continuous and low-volume feed and slowly increased to attain the goal volume. This makes sure the patient tolerates the regimen and that it can be continued. Parenteral and enteral route feedings are always given on a continuous basis. Nutritional requirements can be met with by many methods:
- Diet rich in protein and calorie content (includes oral nutrition supplements)
- Diet with high protein and high calorie, supplemented with enteral feeding
- Feeding through enteral route
- Parenteral nutrition
| General guidelines for nutritional assessment, intervention, and indications for nutritional therapy are as follows:|| |
- Adults with <15%–20% TBSA burn injury will be able to get adequate nutrition through oral route. Adults with >15% TBSA burn injury and children with >10% burn injuries require nutritional support.
- Patients affected with greater than 20% burn injury and/or inhalation injuries need close observation and may require enteral feeding. Patients on therapeutic diets and those with poor nutrition status on admission are candidates for additional nutritional support.
- Inadequate dietary intake of in postadmission period due to facial or hand burns.
- Early enteral feeding preferred for its gastrointestinal benefits in burn injury patients.
- Nasojejunal feeding is considered if nasogastric feeding is unsuccessful.
- Second choice for nutritional support is total parenteral nutrition (TPN). It effectively corrects the undernutrition and insufficient energy intake. The disadvantages include infection of central venous access and sepsis with increased mortality in severely burned patients.
Factors affecting intake of diets: Anorexia, nausea, or vomiting prevents the patient from taking adequate nutrition orally. Pain of wound and procedures such as change of dressing also affect dietary intake. Constipation associated with frequent sedation and diarrhea due to changes in intestinal flora prevent the effectiveness of the nutritional strategies. Frequent surgical interventions and psychological alterations are also vital factors in nutritional therapy.
Energy requirements are increased due to enhanced expenditure energy associated with large area burns. This is due to pain, anxiety, agitation, and heat loss during dressing changes. Severely injured patients on mechanical ventilation or under sedation have reduced energy needs. A decrease in energy requirements by as much as 30% is achieved in critically ill patients by chemical neuromuscular paralysis. The primary aim is to balance the increased caloric needs due to hypermetabolism and at the same time to avoid overfeeding.
Initial estimation of caloric needs is by using weight of the patient when BMI is ≤30 kg/m2 (Class 1 obesity). If BMI is >30 kg/m2, adjusted body weight is used for estimation. The ultimate goal is to minimize weight loss. Caloric need estimates are done using the following equations at the time of admission:
- Zawacki: Resting metabolic rate (RMR (kcal/day) = 1440 × BSA (m2).
- Xie: RMR (kcal/day) = (1000/BSA [m2]) + (25 × BSAB [m2]).
Curreri formula (1972) calculates the approximate calories required to compensate for the patient’s weight loss. Many older formulas tend to overestimate current metabolic requirements. Energy expenditure fluctuates following burn injury. Fixed formulas have the disadvantage of a tendency to underfeeding at times of highest energy utilization. They lead to overfeeding late in the course of treatment. Recent formulas use different variables in the calculation and are more accurate.
Underfeeding is common with fixed weight-based equations used in ICU for calculating nutritional needs. Stress factors used in Harris–Benedict equation are also unreliable. Fatty liver infiltration of overfeeding results in increased infection-related complications. Hildreth and Galveston equation carries the same risk of overfeeding in children. Hence, indirect calorimetry is considered as the gold standard for estimation of energy requirements in adults and children. Toronto equation, based on multiple regression analysis of calorimetric studies, is a good alternative. Estimation of energy needs is a challenging task in the absence of calorimetry. In such situations, Xie et al. and Milner et al. methods are useful., Xie et al. formula: Energy expenditure (kcal/d) = (1000 kcal × BSA [m2]) + (25 × %BSAB) (BSA—body surface area: BSAB—percentage of TBSA burn).
Harris–Benedict equation is most commonly used for estimation of caloric needs. Total energy expenditure (TEE) has three components, namely, BEE, voluntary activity, and thermal effect of food. Gender, age, weight, and height of the patient are used to calculate the estimated BEE using this equation. Harris–Benedict formula is not accurate, but for practical reasons it is often used. The ideal body weight is used in the calculation of requirements, and BEE must be adjusted for activity and injury level. Activity factors are usually 1.2 for patients confined to bed and 1.3 for patients out of bed. Men: BEE (kcal) = 66.5 + 13.75 W + 5.0 H − 6.78 A, Women: BEE (kcal) = 655 + 9.56 W + 1.85 H − 4.68 A (W = weight in kilograms, H = height in centimeters, A = age in years). The patient’s energy requirements are not constant and change frequently during the course of hospitalization. Many criteria are not included in this formula, and the factors that needs to be considered are as follows:
- Malnutrition in the presence or absence of TB and HIV/AIDS and the presence of preinjury protein-energy malnutrition is an important factor.
- 30–33°C is considered optimal thermoneutral temperature for the burn patient. The ambient temperature has an effect on the energy requirements.
- Pain, anxiety, and stress increase the requirements.
- In the presence of thermogenesis, overfeeding must be avoided.
- Energy requirements are reduced by 20% in burn patients on ventilatory support.
- Pentobarbital use reduces energy needs to 86% of predicted energy requirements.
- Wound excision and skin cover in the early part of management and availability of artificial skin help reduce the requirements.
- Indirect calorimetry when available makes the assessments easy and accurate.
The increased nutritional requirements of major burn injury persists for more than 9–12 months following burn injury. Nutritional needs do not decrease immediately following wound closure. Restoration of muscle mass and strength is achieved by progressive exercise program combined with adequate nutrition.
Toronto formula (TF) is a useful tool where the nutrient intake has been standardized in terms of substrate composition. It is useful in acute stage of burn care. Adjustment is needed with changes in parameters during the process of monitoring.
- EBEE (men) = 66.47 + (13.75 × W) + (5.0 × H) − (6.76 × A)
- EBEE (women) = 655.1 + (9.56 × W) + (1.85 × H) − (4.68 × A)
- W—weight in kilograms, A is age, and H is height in cms.
| Toronto Formula for All Patients|| |
- REE (kcal) = –4343 + (10.5 × %TBSA burned) + (0.23 × CI) + (0.84 × EBEE) + (114 × Temp (C) − (4.5 × days postburn)
- [%TBSA—% of total surface area burn: CI is calories received in the previous 24 h including all dextrose infusions, parenteral, and enteral feedings; Temp is the average of the hourly rectal temperature of the previous 24 h expressed in “C”; and PBD is the number of postburn days].
The Curreri formula calculates energy needs of burn patients, and has the disadvantage that during convalescence period it overestimates the patient’s nutritional needs.
- Following burn injury energy, expenditure is maximum during the early postburn phase (7–10 days postburn) and Curreri equation is most accurate in assessing energy needs.
- This equation has not been validated in recent years. Consider using validated equations, for example, Brandi equation. If Curreri formula is used, compare with averages.
Curreri equation (age 16–59 years): TEE is calculated as (25 kcal × kg actual body weight) + (40 kcal × % TBSAB; Age > 60 calculate as (20 × (weight in kg) + 65 × (% TBSA). [If percentage of TBSAB is greater than 50%, use a maximum value of 50%]. Curreri formula example: A 30 year male/70 kg weight sustained 50% TBSA burn. TEE = 25 kcal × 70 kg + (40 kcal × 50) = 1750 kcal + 2000 kcal = 3750 kcal as total energy expenditure. Caloric needs are overestimated in burn patients by this formula.
The modified Curreri formula is widely used. It calculates energy needs for each patient and is compared with the mean energy expenditure. Modified Curreri = (20 × weight) + (40 × %TBSA) where %TBSA reaches a maximum value of 50 %TBSA.
Ireton-Jones is a complex formula with variables for ventilated patients and for injury status.
- Ventilated patients: 1784−11 (age in years) + 5 (weight in kg) + (244 if male) + (239 if trauma) + (804 if burn).
- For non-ventilated patients: 629−11 (age in years) + 25 (weight in kg) − (609 if obese).
Galveston formula calculation is based on the age group and helps in maintaining body weight.
- Age group 0–1 year: 2100 (BSA) + 1000 (BSA × TBSA)
- Age group 1–11 years: 1800 (BSA) + 1300 (BSA × TBSA)
- Age group 12–18 years: 1500 (BSA) + 1500 (BSA × TBSA)
- where BSA is body surface areas; TBSA is total body surface area of burn.
When to reassess calories needs: Weight gain is common during the resuscitation phase. The fluids are generally mobilized slowly over the next 2 weeks to 1 month period as the wounds heal and the patient recovers. Therefore, as the weight begins to trend downward and the wounds are being closed, it is important to reassess calories and protein requirements. Weight of the patient is monitored closely. There should not be a fall of more than 10% below baseline weight and also should not gain excessive weight.
Direct and indirect calorimetries are the best and accurate means of basal energy expenditure measurement. Direct calorimetry is known as whole room calorimeter monitors and the person is placed inside the calorimeter chamber. There is space for moderate activity inside the chamber and the amount of heat produced is measured. Indirect calorimetry (IC) measures accurate energy expenditure and is considered the current gold standard test. Due to the cost factor and technical issues related to its maintenance, It is not available in all burn care centers. IC machine is connected to the patient by tight-fitting face masks in non-ventilated patients or through ventilators to the patient who are on ventilatory support. Indirect calorimetry measures the total volume of expired gas. Oxygen and carbon dioxide concentrations in inhaled and exhaled air are also measured and analyzed. O2 consumption of the patient is used to calculate metabolic rate by indirect calorimetry. Oxygen consumption (VO2) and carbon dioxide production (VCO2) values derived and metabolic rate is calculated. Indirect calorimetry has another important application that it identifies underfeeding or overfeeding in burn patient. The ratio of carbon dioxide produced to oxygen consumed (VCO2/VO2) is defined as respiratory quotient (RQ).
Metabolism of specific substrates in the body may alter the ratio.
- In unstressed starvation, fat is utilized as a major energy source, which produces an RQ of <0.7.
- The normal metabolism of mixed substrates yields an RQ of around 0.75–0.90.
- Overfeeding is typified by the synthesis of fat from carbohydrate resulting in an RQ of >1.0.
The complications are overfeeding and difficultly in weaning from ventilatory support. In pediatric burn patients high-carbohydrate diets are associated with a decrease in muscle wasting. RQs were never increased over 1.05 and they did not develop any respiratory problems. A metabolic cart is a medical device for measure of O2 consumption. These devices are very expensive; it may not be available in all burn care facilities as they need routine maintenance and calibration. They also require technical expertise and personnel to operate. Indirect calorimetry accurately studies energy needs over a period of 30 min. It cannot be used to calculate 24 h needs. Indirect calorimetry fails to calculate energy loss due to painful procedures like change of dressing change, thermogenesis, and exercise in ambulatory patients.
| Indirect calorimetry—key points:|| |
- Resting metabolic rate (REE) must be estimated on admission to hospital and evaluated at least on weekly once basis till patient condition is stable.
- IC must be performed before daily activities for accurate assessment of RMR. Late night or early morning IC study is ideal for accuracy of results.
- Indications for indirect calorimetry are obesity, development of infection, suspicion of sepsis, evidence of poor wound healing, or ventilator dependency with inability to wean from ventilator.
- Calculate RMR value by IC and multiply by a factor of 1.3 to calculate total energy expenditure. Add 20%–30% to the derived value to compensate for the activity of patient, physical rehabilitation, and stress of wound care and other treatment procedures. The nutrition calculation must be based on this calculation.
Macronutrients (substrates) are compounds found in all foods we consume and they provide the bulk of energy. The metabolic processes involve creation and degradation of many products in the body that are essential for various biological processes in the body. Energy is produced by metabolism of three macronutrients carbohydrates, proteins, and lipids via different pathways [Figure 3].
The role of visceral proteins in critically ill patients: Albumin, transferrin, transthyretin, and retinol-binding proteins are visceral proteins and are mostly synthesized in liver. Inflammation and impaired liver functions result in low blood levels of visceral proteins. Hypoalbuminemia is due to “capillary leak syndrome” characteristic of critically ill patients. The capillaries are more permeable and albumin escapes into the interstitium. Distribution of albumin gets affected with an infusion of various fluids used for volume resuscitation of sick patients. Hence, albumin is not a good tool for assessment and cannot be used for monitoring of the nutritional status. Patients with <50% of TBSA burns, show a rapid and consistent increase in levels of albumin and transthyretin from 12 to 43 postburn days. Biweekly measurements show a decline for those who died between day 20 and day 43 postburn period.
Transthyretin levels indicate poor prognosis when less than 50 mg/dL or failure to increase of 40 mg/L/week. Immunonutrient-rich in nucleotides and omega-3 fish oil decreases the mortality rate along with decrease in recurrence rate of bacteremia in sick patients in intensive care. Increased proteolysis following severe burn results in loss of more skeletal muscle daily. Protein administered must meet the daily needs, give extra allowance of substrate to prevent loss of lean body mass, support wound healing, and provide an adequate immune function. With limited availability of calories, protein is used as energy source. The reverse is not true. Excess of calories supplemented will not increase protein synthesis or retention, leads to overfeeding. There is no reduction of the catabolism of endogenous protein stores by supra normal doses of protein supplementation. It reduces negative nitrogen balance by facilitating protein synthesis. Protein needs for adult burn injury patients are 1.5–2.0 g/kg/day and children need 2.5–4.0 g/kg/day. Maintain nonprotein calorie to nitrogen ratio between 150:1 for burns involving small area and 100:1 for larger area burns. Loss of muscle protein in burns patient is due to the hormonal and pro-inflammatory response despite high rates of nutritional therapy.
Calculation of protein needs based on TBSA of burn: Protein supplementation must be based on various factors such as wound status, medications received by the patient, renal and liver function status. All patients with >30% TBSA burn receive glutamine enteral supplementation. Based on ideal body weight, Glutasolve powder is given to provide 0.3–0.5 g/kg/day of protein [Table 3]. If the patient develops multisystem organ failure or encephalopathy, glutamine supplementation must be discontinued.
|Table 3 Protein estimation in adults burn patients based on the actual or lean body weight|
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Protein requirements—key points (for adult burn patients using actual weight):
- Adults with extensive burns require protein need at 3.0 to 4.0 g/kg/day. Adults with BMI > 30 require protein at 2.0 g/kg/IBW
- Desirable nonprotein kcalorie to nitrogen ratio (NPC:N) in adult is 120 to 150:1. The desirable ratios are as follows:
- 80:1 in patients with most severe stress
- 100:1 in severe stress condition
- 150:1 in when patient is in unstressed condition
- 150:1–200:1 adequate intake for stable patients
Amino acids give cells their structure. They are essential in transport and storage of nutrients and carry out many important body functions. They supply energy to liver. Muscles, bones, skin, and hair require amino acids for tissue repair and wound healing. Functions of organs, glands, tendons, and arteries are also dependent on amino acids. They play an important role in removal of all kinds of waste deposits and products of metabolism. Efflux of glutamine, alanine, and arginine from skeletal muscles and organs take place in large amounts following burn injuries. They play a unique role in recovery following burn injuries and their supplementation is crucial for final outcome of optimal results.
Glutamine: There is a rapid depletion of glutamine from muscles and serum following burn injuries:
- Glutamine acts as a direct energy source for lymphocytes and enterocytes.
- Maintains integrity of small bowel and preserves gut-associated immune functions.
- It is a source of energy for hepatocytes. It maintains integrity, permeability, and immune function of small intestine.
- Heat shock proteins provide cellular protection following stress caused by burn injuries. Glutamine increases the production of heat shock proteins. Glutamine is a precursor of glutathione, which is a critical antioxidant.
- Glutamine improves wound healing.
- Glutamine is administered at a dose of 2.5–0.3 g/kg/day. It helps to reduce mortality and shorten the length of hospital stay in burn patients.,,
| Arginine|| |
- Stimulates T lymphocytes and augments performance of natural killer cells.
- Improves resistance to infection by enhanced nitric oxide synthesis.
- Improvement in wound healing and immune responsiveness has been documented following administration of arginine in burn patients.
- Zinc supplementation in high doses leads to copper deficiency., During high dose supplementation of micronutrients, the possible interactions between them must be considered.
Carbohydrates: High-carbohydrate diets have a protein-sparing effect and promote wound healing. Hence, carbohydrates are favored and extremely crucial part of the diet plan for burn patients. Glucose can be oxidized and used in severely burned patients at a maximum rate of 7 g/kg/day only. Even though severely burned patients have high glucose levels, it is not in sufficient caloric amount required to prevent loss of lean body mass. Excess of glucose more than what can be used in the body leads to hyperglycemia. Conversion of glucose to fat occurs and there is an associated glucosuria, dehydration, and leads to respiratory complications.
Glycemic control in burn patients by insulin therapy: Acute injury and hormonal environment of stress due to burn injuries leads to insulin resistance. Insulin maintains adequate and satisfactory blood sugar levels. Excessive growth hormone due to stress response opposes the effect of insulin in the liver and in peripheral tissues. This causes lipolysis by uncoupling insulin-stimulated P1 3-Kinase from its downstream signals. A decrease in anabolic (Somatotropic) peripheral effect of GH is due to a decrease in IGF-1 and IGFBP-1 hormone that catalyze skeletal hypertrophy and protect myocytes from protein catabolism. Anabolic effects never manifest since secretion of IGF-1 is inhibited, even though there is GH-driven increase in insulin resistance and an increase in lipolysis. Glucose levels between 5 and 8 mmol/L has several clinical benefits of good graft uptake, lesser infectious complications and ultimately decreased mortality. The standard target of 100–150 mg/dl is maintained in other critical patients in ICU. Exenatide is a new incretin that inhibits glucagon secretion and decrease external insulin requirement in pediatric burn patients. Infusion of insulin, along with high-carbohydrate, high-protein diets, has many clinical benefits in severely burned patients. Donor site healing improves; lean body mass and bone mineral density are maintained. Muscle protein synthesis is enhanced, wound healing is accelerated, and there is a decrease in length of hospital stay. Patients on insulin therapy require close monitoring to avoid hypoglycemia.
Lipids are recommended only in limited amounts. Fat as a nutrient prevents deficiency of essential fatty acid. During the hypermetabolic state there is an increase in beta-oxidation of fat and that provides fuel. Lipolysis is suppressed after burn injury. Use of lipids as a source of energy is decreased. Only 30% of free fatty acids are degraded. Remaining free fatty acids go through reesterification process and get accumulated in the liver. Immune function is adversely affected by increased fat intake. Very low-fat diets that supply no more than 15% of total calories is recommended for patients. The amount and the composition of fat must be considered., Multiple low-fat enteral formulas are available. For patients receiving PN on a short-term (<10 days) it may not be necessary to add lipid emulsions.
Micronutrients: Intense oxidative stress and elevated inflammatory response are characteristic features of severe burn injury. They lead to a rapid and sustained depletion of the endogenous antioxidant defenses. The oxidant defense mechanisms are highly dependent on levels of micronutrients., Vitamin and trace element metabolisms are crucial in development of immunity and wound healing.
- The process of wound healing, skeletal muscle bulk, and immune functions are adversely affected due to deficiencies of vitamins A, C, and D, trace elements such as Fe, Cu, Se, and Zn.
- Increased epithelial growth of vitamin A decreases time of wound healing. Retinoids favor macrophagic inflammation that supports wound healing.
- Vitamin C is important for creation of collagen and their cross-linking functions.
- Vitamin D becomes deficient following burn injury. It contributes to bone density. The exact role of vitamin D and optimal dose following severe burn remains unclear.
- High doses of zinc supplementation lead to copper deficiency.
The trace elements such as Fe, Cu, Se, and Zn are important for both cellular and humoral immunity. Trace elements are lost in large quantities in exudates of burn wounds.
- Zinc is important for function of lymphocyte, replication of DNA, and synthesis of protein. It is critical for wound healing also.
- For oxygen-carrying proteins, iron (Fe) acts as an important cofactor. Selenium enhances cell-mediated immunity [Table 4].
- Copper is required for optimal wound healing, synthesis of collagen. Its deficiency is associated with decreased immunity and cardiac arrhythmias. It leads to worse outcome in patients with burn injuries.
- Morbidity of severely burned patients improves with replacement of these micronutrients.
Ceruloplasmin and hypoferremia: In critically ill burn patients, normal iron handling mechanisms are altered. The resultant hypoferremia contributes to systemic inflammation.
Ceruloplasmin (Cp) is an acute phase reactant protein important in regulation of iron metabolism. Cp converts ferrous iron to ferric iron, which is a less reactive form and helps in binding to ferritin. The ferroxidase activity of ferritin is important in iron handling mechanisms. Genetic absence of Cp causes iron accumulation in many organs as there is a decrease in export of iron. Hypoferremia and inflammation occur due to an early decrease in Cp oxidase activity in both burn and nonburn trauma patients. There is an increase in the risk of iron-induced injury following blood transfusions in patients with critical burn injuries. “Stress hypoferremia,” a low iron status in critically ill or injured patients, occurs irrespective of severity of injury, blood transfusions status, surgical procedures, or sepsis. Some studies have reported links between iron status and severity of injury.,
- Development of low serum or plasma iron concentrations in burn injury patients is documented. Critical burn injury patients develop anemia.,
- The changes that occur in the first week following burn injury are related to low iron binding capacity and serum transferrin concentrations. Soluble transferrin receptor levels are a reliable indicator of iron deficiency anemia in hospitalized patients with acute illness and there is a significant lower level of iron in burn patients than in trauma patients until day 14. 
The changes are similar to hypoferremia of inflammation related to cytokine induced release of hepcidin., Reduced Cp oxidase activity carries the risk of iron-mediated injury following transfusion with aged blood near its 42 day storage limit.
Micronutrient supplementation is crucial in reducing the mortality and morbidity in critically ill patients following burn injuries. Deficiency results in lowered host defenses and impaired production of antioxidants. Copper, zinc and selenium are lost in larger amounts in burn patients in the exudates.,, The intravenous route is best for their replacement. Duration, dose and timing of micronutrient supplementation are important considerations for improving their utility.
Addition of copper, zinc, selenium, vitamins B1, C, D, and E to the supplement food is of great value [Table 5]. They decrease fat breakdown, improves wound healing, and shorten hospital stay. Thiamine replacement improves lactate and pyruvate metabolism. Vitamin C and E supplementation enhance wound healing. It is recommended that the patients receive 1.5–3 times the dietary reference intake. Loss of vitamin D must be supplemented to prevent bone loss. Increased oxidative stress in burn patient enhances depletion of micronutrients.
| Vitamin-D requirement in adult burn patients:|| |
- 25OH-D level following burn is lower than healthy subjects on admission.
- Elevation in levels of 25OH-D and free 25OH-D with 100,000 IU of cholecalciferol is not clearly documented in burn patients compared to healthy subjects.
- During acute burn care, higher cholecalciferol doses should be considered.
- Quarterly vitamin D injections (200,000 IU) helped muscles in adult burn patients.
Immunonutrition: The aim of immunonutrition is to achieve wound healing and improve immune function. Nutritional formulas enriched with micronutrients help in better outcome of patients. Severely burned children, on tube fed formula with omega-3 fatty acid, arginine, histidine, and vitamins A and C were compared to children on commercial formulas. Children on IED had distinct benefits of reduced wound infections, shorter length of hospital stay, and showed improved survival rates. Immunonutrition with immune-enhancing diets (IED) showed beneficial effects and lead to
- improved respiratory gas exchange,
- an improvement in neutrophils recruitment,
- improved cardiopulmonary function, and
- reduced the number of days required for mechanical ventilation and length of hospital stay.
According to some studies, there is no difference in major outcome variables with immune-enhancing diet compared to high protein stress formula diets. Since the patients are on high volume feedings, conventional diets supply an adequate dose of most immune-enhancing nutrients. It is concluded that no formula or calculation is perfect, but most are sufficient to prevent nutrition-related complications.
| Immunonutrition as an Adjuvant Therapy for Burns|| |
Immunonutrition is feeding along with enteral route or total parenteral nutrition supplementations. They are enriched with various pharmaconutrients. The most essential and commonly used are arginine, glutamine, omega-3-fatty acids, nucleotides, and antioxidants: copper, selenium, zinc, vitamins B, C, and E. They improve immune response in patients and also modulate and attenuate the severe responses of inflammation [Table 6]. Complete supplemented nutritional formulations are “Immune modulating diets” (IMD). The potential targets for immunonutrition include:
- gastrointestinal: the gut mucosal barrier function has to be maintained,
- boost cellular defenses, and
- modulation of local and systemic inflammation.
The common nutrients added in immunonutrition formulas include glutamine, arginine, branched-chain amino acids (BCAAs), omega-3 (n-3) fatty acids, and nucleotides. Omega-3 fatty acids form major component of “immune-enhancing diets.” The most used common formulas contain linoleic acid, an omega-6 fatty acid. They go through the process of synthesis of arachidonic acid, precursor of pro-inflammatory cytokines (e.g., prostaglandin E2).
- Lipids containing a high percentage of omega-3 fatty acids do not promote pro-inflammatory molecules during their metabolism. The beneficial effects are an enhanced immune response, reduced levels of hyperglycemia, and improved clinical outcomes.
- An omega-6 to omega-3 ratio of 4:1 is ideal. Omega 6:3 ratio is maintained between 2.5:1 and 6:1 in enteral formulas and the immune-enhancing diets have omega 6:3 ratio closer to 1:1. Further understanding and research are required to identify the ideal composition and amount of fat in nutritional support for burn patients.
| Combined Immunonutrients|| |
- Glutamine is the most commonly used immunonutrient. Various combination of immunonutrient regimens have been used in patients with extensive burn injury.,,,
- Gottschlich formula has reasonable impact on burn wound infection rates and length of stay expressed as days per %TBSA. This formula is a high-protein, low-fat diet with a low-linoleic acid content, supplemented with omega-3 fatty acids, arginine, cysteine, and histidine. Vitamin A, zinc, and ascorbic acid are also added in this formula.
- Kurmis and associates (2010) have recommended that glutamine alone be used in patients with severe burns. The European Society for clinical nutrition and metabolism (ESPEN) has not issued statement regarding combination therapy.
Probiotics are defined as live microorganisms that when administered in adequate amounts, confer a health benefit on the host (WHO). Metchnikoff, a Russian Scientist, introduced the concept of probiotics. Probiotics are found in large quantities in yogurt, kefir, and fermented foods. They help enhance the defensive action of the cells that line the gut. They stimulate healthy immune function and inhibit the growth of viral and bacterial pathogens. High through Table put-sequencing technology and advances in meta-genomics have opened up new approaches for the future of probiotics research. The study of molecular biology and genomics of Lactobacillus help in enhancing immune function and as an adjuvant treatment of cancer. Other uses are in treatment of antibiotic-associated diarrhea, travelers’ diarrhea, pediatric diarrhea, inflammatory bowel disease, and irritable bowel syndrome. The benefits of probiotics include:
- relief of stress, anxiety, and depression,
- mood improvement via gut-brain signaling,
- protection against free radicals,
- improvement of glucose tolerance,
- allergy prevention,
- cholesterol reduction, and
- beneficial effects in liver disease.
The commonly used marker of inflammation is CRP. Treatment with prebiotics showed decreased levels of CRP more than bacterial sonicates. It is associated with reduced levels of serum hs-CRP and an increase in serum albumin levels.
Probiotics effects on nutritional status: Lactobaciillus johnsonii is a species in the genus Lactobacillus. The probiotic L. johnsonii La1 (LC1) in fermented milk has beneficial effects on serum albumin levels.
- Suppresses infections and in elderly patients it improves nutritional and immunological status.
- It has a positive effect on albumin biosynthesis with increased serum albumin levels.
- Decrease in TNF-α was identified in the LC1 treated group.
- Blood phagocytic activity is a natural immunity marker in patients with low serum levels. An increase in blood phagocytic activity has been documented in the LC1 treated group.
Synbiotics enteral nutrition in the early burn period helps to reduce the inflammation of the stress response and also increases serum levels of albumin. Probiotics are not involved in stimulation of production of gastrointestinal protein synthesis and they do not reduce severity of colitis. The probiotics-induced elevation in liver protein and synthesis of plasma proteins are modified through a signaling mechanism between the gut and liver. Effect on weight gain: Infants on a supplement dose of prebiotics have slightly better weight gain.
Prognostic inflammatory and nutritional index: PINI is a clinical prognostic index assessment tool related to outcome prognosis in hospitalized elderly patients and in critically ill patients with acute respiratory failure., Serum CRP, alpha 1-acid glycoprotein (AAG) and albumin (ALB) levels are considered in a single score.
Vegan nutrition diet includes no animal products and refers to their nutritional aspects. Vegan diets are based on the belief that high animal fat and protein diets are detrimental to health. Vegan diets must be planned and executed carefully. Vegan diets may be deficient in a variety of nutrients and a careful planning is essential to avoid deficiencies of such nutrients. Riboflavin (vitamin B2), vitamin B12, and vitamin D are the common vitamins deficient and also calcium, iodine, iron, zinc, long-chain fatty acids EPA and DHA, and omega-3 fatty acids need a planned supplementation.
Vitamin B12: Vegans must follow one of the dietary options for getting sufficient levels of vitamin B12:
- 3 micrograms of vitamin B12 will be reached by consuming fortified foods 2–3 times per day.
- To get at least 10 micrograms of B 12, take 1 vitamin B12 supplement per day.
- To get at least 2000 micrograms, take 1 weekly B12 supplement.
Omega-3 fatty acids (O3FA) are available in plenty in algae, hemp-seeds, and hemp-seed oil. Other rich sources include flaxseeds and flaxseed oil, olive oil, canola (rape seed) oil, and chia seeds. Walnuts and avocado are the other rich sources of O3FA. Calcium: Enough calcium supplementation can be achieved with high-calcium food, such as fortified soy milk and other plant based milks, taken on three servings per day. Other rich sources of calcium are almonds, hazelnuts, kale, collard greens, Chinese greens, etc., Calcium supplement or other calcium-fortified foods may be necessary depending on the deficiency status. Iodine is available from sea vegetables and iodized salt. Iron: Vegans must eat iron-rich and vitamin C-rich foods daily. Dark leafy greens together with other sources of vitamin C are ideal for supplementation. Choline: Vegan diet sources rich in choline are soy lecithin, cauliflower, spinach, wheat germ, firm tofu, kidney beans, quinoa, and amaranth. Adequate intake of choline per day for adult women is 425 milligrams; pregnant and breastfeeding women need greater amount. An adult male requires 550 mg/day. Choline has anti-inflammatory effect. Adequate and quality choline requirements may be achieved with wheat germ (172 mg/cup), Brussel sprouts (63 mg/cup), and broccoli (62 mg/cup).,
| Dietary Modifications in Special Situations|| |
Endocrine disorders: Normal functioning of many endocrine organs such as thyroid, pancreas, etc., is also linked to the nutritional status. Thus, nutritional imbalance can hamper their normal functioning. Various endocrine disorders such as obesity, thyroid disorders, and diabetes have been linked with dietary modifications. Increased prevalence of endocrine disorders is associated with overnutrition. Dietary patterns actually program the different mechanisms associated with these disorders. As in case of diabetes mellitus, presence of transcription factor TCF7L2 can be regulated by fat and glucose rich diet. All the dietary components affect endocrine systems of the body. Chronic kidney disease: Dietary modifications both improve symptomatology as well as progression of kidney diseases. Many factors like type and severity of renal disease, nutritional status, dry weight, dietary intake, co-morbid diseases, physical activity, biochemical markers, and also the adjusted body weight help in calculation of energy requirement of these patients.
Nonnutritional strategies in the management of hypermetabolism aims at attenuation of the hypermetabolic stress response to burn injury and are recommended in addition to early enteral nutrition. The following factors help reduce the severe hypermetabolic response of burn injuries:
- Nursing environmental temperature at 28–30°C is ideal. The warm ambient temperature reduces the metabolic needs in burn patients.
- Excision and coverage of burn wounds as early as possible reverses the severe catabolism associated with burn wounds.
- Protein building mechanisms of the body can be strengthened by using protein synthesis stimulating agents.
- Metabolic resuscitation of burn injury patients includes adequate pain control. Early institution of exercise therapy program helps in rehabilitation in such patients.
Propranolol use in children has shown more positive effects than in adult patients with burn injuries. Nonselective beta-blocker propranolol in adults help decrease in requirements for blood transfusions, hastens wound healing, and reduces the number of skin graft procedures required. These are associated with reduced length of hospital stay (LOS). The dose of propranolol that reduces basal heart rate by 20% has significant effect in decreasing the release of cytokines or stress hormones. This leads to a reduction in both hypermetabolism and hypercatabolism response in critically ill burn patients. Propranolol is started at the end of first week of burn injury., It is administered at a dose of 0.1 to 3.8 mg/kg/day (an average maximum dosage of 0.61 mg/kg/day). The mean heart rate decreases by 25% during 4 weeks of treatment. It is important to monitor the patients for possible bradycardia and hypotension.
Fenofibrate, a fibrate is an anti-hyperglycemic therapy without the risk of hypoglycemia. Administration of fenofibrate in the early acute phase reduces blood glucose levels in severely burned patients. It also causes blockade of catecholamines, with attenuation of long-term postburn effects of catabolic and hypermetabolic responses. Fenofibrate alone or in combination with propranolol reduces insulin resistance, enhances wound healing, improves cardiac function, and reduces sepsis-related complications when administered for duration of one year postburn. Proposed clinical trials are on therapeutic, physiological, and metabolic effects of propranolol, fenofibrate, and fenofibrate plus propranolol on the improved clinical outcomes, and the long-term recovery, rehabilitation, and QOL in burned patients. Oxandrolone are nonselective beta-blockers that decrease mortality. The length of hospital stay is decreased at a dose of 10 mg every 12 h. The beneficial effects include prevention of loss of weight, protein catabolism, and hasten healing time both during acute and rehabilitation periods. It is useful in the metabolism of bone also. Children who receive oxandrolone at 0.1 mg/kg/12 h also get the same benefits as seen in adults. Liver function requires a close monitoring during the administration of oxandrolone.,
The best cost-effective pharmacotherapy for burns hypermetabolism is propranolol and oxandrolone. Clinical research is underway for the role of a combined therapy with propranolol and oxandrolone (NCT00675714). Early administration of both drugs alone/in combination during the first week of burn injury is under study. Propranolol administration begins at the end of the first week, after the initial resuscitation phase and oxandrolone is administered a little later. Treatment duration must correspond to the hospitalization stay and modifications are required regarding propranolol and oxandrolone during septic events. A prolonged administration of these drugs during the rehabilitation phase might be considered with better clinical outcomes.
Recombinant human growth hormone: rhGH promotes utilization and synthesis of protein. When used in patients’ burns with >40% TBSA, it has well documented anabolic effects in patients with major burn injuries and those undergoing major surgical procedures. In adult patients with burn injury, their effects are not better than oxandrolone. Use of rhGH has no adverse impact on mortality but has adverse hyperglycemia effects. In children with critical burn injuries, rhGH effectively preventing growth impairment (stunting) caused by GH deficiency of critical burn injuries. Treatment with rhGH (0.05–0.2 mg/kg/day) enhances skin graft donor site healing, reduces hypermetabolism and growth deficit., Treatment for up to one year has shown to be effective and safe. Ideal duration of treatment is still under study and patients may be benefited from a long term administration of rhGH.
Monitoring of nutritional support: The goal of nutritional support is to get back normal body levels of all nutrients and achieve a state of metabolic equilibrium. Objective methods of assessment and monitoring of nutritional support of a burn patient is a challenge. They cannot be measured by one variable alone as it is a complex phenomenon. Weight of the patient, lean body mass, nitrogen balance, and serum proteins estimation are the most common factors used. Body weight is easy to measure and is useful to assess for nutritional monitoring in general population but it is very misleading in burn patients. Critical burn patients receive large volume fluid resuscitation in initial phase of injury, may have a weight gain of about 10–20 kg. Later on with diuresis there may be a reduction in body weight and the time course is unpredictable. Ventilator support, infections, and hypoproteinemia are also associated with additional fluid shifts. These make the body weight measurement a very unreliable gauge of nutrition. Loss of lean body mass that occurs in the early period of burn injury is marked by the presence of increased total body water in patients that persists for weeks following burn injuries. Long-term body weight monitoring is valuable especially during the rehabilitation phase. Nitrogen balance: Nitrogen occurs in all organisms. Primarily, it is fundamental component of amino acids, of the nucleic acids and of energy transfer molecule adenosine triphosphate. Nitrogen intake and losses are good predictors of protein metabolism. Adequate quality protein supplementation is crucial in nutrition therapy following burn injury. An increase in the total body protein levels associated with growth indicates a positive nitrogen balance. Burn injuries, trauma, and periods of fasting are characterized by negative nitrogen balance. Determination of urinary urea nitrogen (UUN) and dietary nitrogen intake are used in calculation of nitrogen balance for burn injury patients: Nitrogen balance = Nitrogen intake in 24 h − [1:25 × (UUN + 4)]. (Factor 4 is nitrogen losses from non-urinary sources) The two constants used in the formula may result in errors in calculation. A value of 4 g/dL is added to UUN to calculate the total urinary nitrogen. But in burn patients total urinary nitrogen may exceed this value and lead to an underestimation of nitrogen loss. To account for loss of protein-rich exudates from burn wounds, the estimated total urinary nitrogen value is multiplied by a factor of 1.25. This also can underestimate nitrogen losses.
Albumin and Prealbumin are acute phase proteins. During acute phase inflammatory processes such as infection, burns, and trauma, these protein levels are reduced and they are called negative acute phase reactants. Burn injuries elicit local and systemic inflammation, increased vascular permeability and hypermetabolism that lead to decrease in serum albumin levels. Prealbumin has a short half-life of 2–3 days and is a better indicator of nutritional repletion. Prealbumin levels fall rapidly following injury, has a slow recovery, and are not accurate estimators. Serum albumin is a negative acute-phase reactant protein. There is an enhanced acute-phase protein synthesis in the liver due to high levels of inflammatory cytokines in burn injury patients. Synthesis of albumin as a negative acute-phase protein decreases in the acute inflammatory response phase of burns and result in hypoalbuminemia. Serum albumin level is a good marker of wound healing, but poor marker of nutritional status in patients with burns. Burn wounds have a high vascular permeability and produces exudation of protein. Fluid resuscitation also makes proteins estimation an unreliable tool. Serum albumin and CRP levels (half-life of about 20 days and 4–6 h respectively) fluctuate independent of each other. Hypoalbuminemia is a good prognostic marker correlating with mortality and morbidity in hospitalized patients. It also indicates disease prognosis and development of complications. There is no difference in serum albumin levels in relation to the levels of caloric intake in individuals with burn injuries.
| Key points:|| |
- Serum levels of albumin are not good indicators of nutritional status and they are not reliable as nutritional markers. Nutritional status assessment in burn injury patients with albumin is unreliable.
- There is no relationship between good caloric intake and serum albumin levels. Malnutrition or inadequate provision of nutrients is not reflected as low albumin levels either.
- There is a large body pool of albumin (half-life of 20 days).
- The state of hydration and renal function of patients affect serum albumin concentrations.
- When albumin pool gets depleted, it takes 14 days to return back to normal.
Prealbumin and CRP levels: Mediators of inflammation associated with sepsis, trauma, and burn injuries alter the metabolism of negative acute phase proteins. There is a reduction in their synthesis and also dilution of negative acute phase proteins. The values of albumin, prealbumin, and transferrin in the acute phase of the thermal injury are less sensitive index of nutritional repletion. Following the acute phase when intake of nutrition is adequate serum prealbumin level (half-life 48–72 h) gradually rises. CRP, a positive acute phase protein levels gradually decrease. Persistent low level of prealbumin in the presence of normalizing CRP level is a good indicator of protein or calorie deficiency. Estimation of prealbumin and CRP levels must be done twice a week for all patients with critical burn injuries in BICU and patients who do not require BICU care must be evaluated at least once in a week. Serum albumin levels and caloric intake do not link with each other, but are associated with CRP and wound healing. Serum albumin is not a good index as a nutritional status marker in patients with burn injuries.
Prealbumin as a Marker for Nutritional Evaluation: Prealbumin is a hepatic protein, serves as a good indicator for assessment of the severity of illness due to malnutrition. Prealbumin is reliable and a preferred marker for protein malnutrition in critical burn injury patients. Most important source of prealbumin is liver. Significant levels are secreted from the choroid plexus, embryonic yolk sac pancreatic islet cells, and gastrointestinal mucosal enterochromaffin cells are other sources. Estimation of prealbumin serves as a sensitive and most cost-effective method for estimation of nutritional status. Prealbumin levels are accurate predictor of patient recovery and they correlate well with patient outcomes. Liver continues to produce prealbumin until late in liver disease. Prealbumin levels are estimated twice weekly in high-risk patients, to identify declining nutritional status of the patient, improve patient outcomes, shorten hospital stay duration in cost-conscious situations.
| Key points:|| |
- Prealbumin level estimations allow early recognition and timely nutritional intervention.
- In a normal adult person consuming food that provides only 60% of required proteins, prealbumin levels start decreasing after 14 days.
- In children with severe protein calorie malnutrition, protein supplementation rises the prealbumin above baseline levels within 48 h and takes 8 days to reach normal levels.
- Aim of nutritional support must enhance prealbumin levels by 2 g/dL (20 g/L) per day.
Limitations of prealbumin level: Acute alcohol intoxication rises prealbumin levels. This is due to leakage of proteins from damaged hepatic cells. The elevated prealbumin level returns back to normal after one week. Prednisone therapy and use of progestational agents increases prealbumin levels. Zinc deficiency lowers prealbumin levels and vitamin deficiencies do not have effect on the serum levels of prealbumin.
| Prealbumin—key points:|| |
- Prealbumin levels below 15 mg/dL (150 mg/ L) require the services of a nutritional team and therapy must be planned and monitored by the team.
- An increase in prealbumin levels occurs within 4–8 days of nutritional supplementation therapy.
- Within 8 days of nutritional support, a prealbumin level of 4.0 mg/dL (40 mg/L) must be achieved, failure to achieve indicates a poor prognosis and need for additional support measures such as oral or intravenous hyperalimentation.
- If prealbumin level continues to rise, it indicates that patients are receiving at least 65%of their requirements of protein and energy.
Functional tests are useful but not absolutely essential for routine assessment of nutritional status. For voluntary muscle strength exercise tolerance test and hand dynamometry are the common tests done. Strength of respiratory muscles is assessed by measurement of peak expiratory flow rate. Other scores of well-being such as mood score and quality of life score and in elderly patients activity of daily living score are used.
| Imaging techniques for nutritional monitoring:|| |
- Bioelectrical impedance analysis (BIA) sends a weak electric current throughout the body to calculate body composition. It is a simple, noninvasive, and indirect method of assessment. Total body water and body’s fat-free cell mass estimate are based on the body’s resistance to passage of electrical currents. Shifting of fluids characteristic of burn injuries affects this method of measurement. They are used in research only due to availability and cost involved.
- Dual X-ray absorptiometry (DEXA) scan is a measure of bone density and is also used to estimate lean body mass.
| The most common parameters used in assessment of nutritional therapy are as follows:|| |
Different burn care centers have their own protocols of burn managements. The most commonly used tests for nutritional assessment are prealbumin estimation in 86% of centers, Body weight measurements are followed in 75%, and calorie estimation by direct or indirect calorimetric studies in 69% of centers. The other estimates made are serum albumin (45.8%), analysis of nitrogen balance (54%), and transferrin levels in 16% of burn centers.
Formulas for nutrition in burn patients: Milk and eggs were the main constituents of nutritional formula for burn patients, before the advent of the latest technologies in nutrition therapy. They successfully provided adequate nutrition but the disadvantage was the very high fat content. Carbohydrates along with protein, fats, and added micronutrients of various quantities and in combinations enteral formula are available commercially.
In burn injury patients, glucose is the preferred energy source. The basis for nutritional plan for burn injury patients includes a diet rich in carbohydrates. Common parenteral formulas contain 25% dextrose with addition of 5% crystalline amino acids and added electrolytes for maintenance levels. Lipid emulsions supplementation three times per week with infusions of 250 mL of 20% is essential to meet fatty acid requirements.
Nutrition support strategies: Evaluate ability of critically ill burn patients to receive enteral feedings at the time of admission. During initial aggressive fluid resuscitation, there is poor intestinal perfusion as a result of disparity in intestinal oxygen demand and perfusion. This important aspect requires careful consideration while choosing the route of feeding. For patients with diminished gut perfusion trophic feeds are ideal and this includes patients who are in need for treatment with vasopressors. Reassessment is done once the patients are hemodynamically stable. A baseline measurement of abdominal girth is obtained on admission. Gastrointestinal output of less than 200 mL with stable abdominal girth measurement indicates that the patient can tolerate gastric feedings. Hourly feeding rate of 0.5–1 mL/kg will be easily accepted. Gradual increase in feeding rate must be done with continuous monitoring of GI output and abdominal girth measurement. The feeding must be stopped when the gastric residuals exceed two times the volume of hourly rate.
Discriminate intravenous lipid administration interferes with platelet function, predisposes to poor immune function, and exacerbate lung injury. Allergy to soy and eggs are contraindicated. Intravenous lipids must be avoided and used when parenteral support is required to be provided in excess of 3 weeks.
Enteral nutrition: Following trauma and severe burn there is gut ischemia and reperfusion during the initial period of resuscitation. Development of sepsis and multiple organ failures are related to these changes. Parenteral nutrition composition selection is crucial in preventing infections and hepatic dysfunction. Composition and rate of administration of solution is more important to avoid such complications. Proper care of the central venous line used for providing this form of nutrition is also essential. Adult and children with burn injuries cannot oxidize efficiently when glucose is administered in excess of 5 mg/kg/min, the goal infusion rates in burn patients. Fluid edema and complications like hepatic steatosis and other metabolic derangements can be prevented by avoiding overfeeding by keeping the glucose infusion within this limit. The incidence of hyperglycemia is also minimized. Amino acid infusions supply the entire estimated protein requirement in critical burn injury patients to maintain the nonprotein calorie: nitrogen ratio of 85:1. Wound healing is enhanced at this level of nutritional support.
The scope of enteral nutrition has improved with advances in
- Endoscopic placement of jejunostomy and gastrostomy feeding tubes.
- Development of various new biomarkers of illness is of great help in guiding the nutritional goals.
- The field of pharmacogenomics has linked the role of nutrition in gene expression.
| Indications of enteral nutrition in critical burn patients:|| |
- Reduced level of consciousness, impaired swallowing, inadequate oral intake
- Impaired gastric emptying, gastric outlet obstruction
- Hepatic failure
- In patients with moderate intestinal failure, for maintaining integrity of gut
- For modulation of stress response. Systemic immune response modifications
- Disease severity attenuation and to provide immune-modulating agents
- Stress ulcer prophylaxis
Early enteral feed via gastric route is preferred in critical burn injury patients for the beneficial effects like attenuation of the stress response, stress‐induced ulcers and increased production of immunoglobulin. Few factors in the initial phase of resuscitation like use of larger amounts of crystalloids, with edema of the intestine and paralytic ileus can prevent early start of enteral feeding. Enhanced capillary leak in the early phase of burns increases the fluid requirement.
Enteral route nutrition support should be started immediately (4–6 h) after large burn injury (>20% TBSA) [Table 7]. Early enteral feeding is safe and beneficial. Impact peptide 1.5 (formerly crucial) is the primary choice formula providing high-nitrogen, peptide-based diet with supplemental arginine, lipid as 50% MCT oil, vitamin C, vitamin A, and Zinc. Start Impact peptide 1.5 @ 20 mL/h and increase as tolerated up to the goal determined by dietitian. Impact peptide 1.5 is to be provided for 7 days and then substituted for a formula with added protein in consultation with dietitian. Do not continue with enteral nutrition if patient shows signs of abdominal compartment syndrome with bladder pressure >20 mmHg.
Enteral versus parenteral nutrition: The enteral nutrition whenever possible has many advantages over the parenteral route. Enteral nutrition helps to maintain the integrity of intestines. They support to keep the tight junctions between intraepithelial cells. It also improves the intestinal blood flow and stimulates secretion and release of cholecystokinin, gastric, bombesin, and bile salts. It also maintains villous height and support IgA producing immunocytes. Within hours of major insult, intestinal permeability changes due to loss of functional integrity thus increasing the risk and severity of infectious complications.
The problem of overfeeding: The pathophysiology of burn injury is complex and a dynamic process with many variables that make estimation of the nutritional requirements very difficult. The complication of overfeeding may occur following institution of an aggressive nutrition therapy in early phase of postburn injury, as the metabolic rate slows and intestinal absorption improves. They are associated with complications such as fatty liver, azotemia, and hyperglycemia that lead to difficulty in weaning the patient from ventilatory support. Due to overfeeding of carbohydrates there is increased synthesis of fat and carbon dioxide that result in elevation of respiratory quotient. There is worsening of respiratory status, and weaning from the ventilator is prolonged. There is mobilization of all available substrates due to burn hypermetabolic response. Development of fatty liver results due to an increase in peripheral lipolysis.
Increased fat deposition in liver parenchyma occurs in overfeeding due to parenteral/ enteral route of nutrition therapy and fatty liver leads dysfunction of immune system and enhances mortality rates. Azotemia results from excess protein supplementation in burn patients. Prerenal kidney injury due to massive fluid shift of burn injury results in increased level of blood urea nitrogen. Patients with azotemia need close monitoring for signs of renal failure as it aggravates the stress on the kidney. If there is no positive response to hydration therapy, reduce the amount of protein in nutritional supplement. Patients with renal failure must continue to get nutritional support. Blood chemistry is regularly monitored for any metabolic derangement and necessary corrective measure taken. Formulas of nutritional needs are used as guidelines. Reassessment of energy requirements are done regularly. Nutritional reassessment is done with standard equations and injury/activity factors at the end of acute hypermetabolic phase. This prevents the problems of overfeeding. Changing status of wounds, physical and occupational therapy activities should be considered for estimating nutritional needs.
| Sepsis and Enteral Feeding Intolerance|| |
Diagnosis of early sepsis in burns patients is crucial for survival of patients. The American Burn Association guidelines for diagnosis of sepsis are based on many criteria. Confirmation of infection requires presence of at least three criteria:
- Fever more than 39°C or hypothermia with temperature less than <36.5°C
- Increased heart rate greater than 110 beats/min
- Increased respiratory rate with more than 25 breaths/min in non-ventilated patients
- In ventilated patients with a minute ventilation of greater than 12 L/min
- Thrombocytopenia with less than 100,000/µL platelet count
- Hyperglycemia, in the absence of preexisting diabetes mellitus (untreated plasma glucose >200 mg/dL or >7 units of insulin per hour intravenous drip or significant resistance to insulin, >25% increase in insulin requirement over 24 h)
- Inability to continue enteral feedings >24 h (abdominal distension or high gastric residuals, residuals two times feeding rate or uncontrollable diarrhea, >2500 mL/day).
Intolerance to enteral route feeding in sepsis adversely affects patients’ nutritional status with increased morbidity and mortality. An increase in mean PCT level and a decrease in prealbumin level are other findings of burn sepsis.,
Nutritional indicators of bacteremic sepsis: In burn patients nutritional assessment parameters for sepsis are crucial for early detection and control of infection. Transferrin, serum albumin and nitrogen balance values are monitored on postburn day 10. Total lymphocyte count, skin test reactivity and percentage of ideal body weight (%IBW) are also taken into consideration. The laboratory findings that predict an imminent septic episode include:
- estimated serum albumin levels <3.0 g/dL (P < 0.001),
- total lymphocyte count value of <1500/MM3 (P < 0.001),
- anergy (P < 0.001), and
- estimated serum transferrin level <150 mg/dL (P < 0.01).
| Features in septic patients with feeding intolerance:|| |
- Lower mean caloric intake is a characteristic feature.
- Ratio between PCT (procalcitonin, infection marker): prealbumin (nutrition status marker) is high.
- Incidence of pneumonia is higher.
- Sequential organ failure assessment maximum score will be higher.
- Inability to wean the patient from mechanical ventilation with a need for prolonged period of ventilation.
- Septic patients with gastric feeding intolerance have a higher mortality rate.
Refeeding syndrome is metabolic disturbance syndrome. Patients who are starved, severely malnourished, or metabolically stressed due to severe illness including burn injuries are prone for refeeding syndrome that develops on starting of nutrition. Excess of food or liquid nutrition supplementation during the initial 4 to 7 days post-burn period is the common cause of refeeding syndrome., Characteristic feature of the condition is a trigger for synthesis of glycogen, fat, and protein in cells. Fluid and electrolyte disorders that accompany the syndrome are reduction of serum concentrations of potassium, magnesium, and phosphorus. Hypophosphatemia is the most common and dangerous, and the signs may mimic cardiac, pulmonary, neurological, neuromuscular, or hematologic symptoms. Severe persistent low serum mineral levels can be fatal.
| During fasting the following body changes occur:|| |
- During fasting, tissue fatty acids and amino acids become the main sources of energy instead of carbohydrates and fat.
- Conservation of red blood cells occurs as the spleen decreases its rate of red blood cell breakdown. Many intracellular minerals become severely depleted during this period, in spite of the fact that the serum levels remain normal.
- In fasting state, insulin secretion is suppressed and glucagon secretion is increased.
During refeeding: Due to an increased blood sugar level, insulin secretion is restored. There is an associated increase in levels of glycogen, fat, and protein synthesis. These processes require and use phosphates, magnesium, and potassium. As the electrolytes are already depleted, their stores are also used up rapidly. The following changes occur during refeeding:
- Formation of phosphorylated carbohydrate compounds in the liver and skeletal muscle depletes intracellular ATP and 2,3-diphosphoglycerate in red blood cells, leading to cellular dysfunction and inadequate oxygen delivery to the body’s organs.
- Refeeding increases the basal metabolic rate.
- Intracellular movement of electrolytes occurs along with a fall in the serum electrolytes, including phosphorus and magnesium. Levels of serum glucose may rise and the B1 vitamin thiamine may fall.
- Cardiac arrhythmias are the most common cause of death from refeeding syndrome, with other significant risks including confusion, coma, and convulsions and cardiac failure.
- Gastrointestinal disturbance like colicky abdominal pain, reflux symptoms, nausea, and early satiety occurs.
Treatment: The most common cause of death in refeeding syndrome is abnormal cardiac rhythms. Blood biochemistry monitoring must be done early in refeeding period so that the underlying electrolyte imbalances can be corrected to avoid mortality.
- Phosphate levels drop to 0.65 mmol/L (2.0 mg/dL) from previous normal level and if the drop happens within 3 days of starting enteral or parenteral nutrition, it is an indication for electrolyte replacement therapy. It is recommended to keep the caloric intake up to 480 kcal/day for at least 2 days during the period of electrolyte replacement therapy.
- Energy intake must be kept at a lower level than normal requirement for the first 3–5 days of treatment of refeeding syndrome.
- Multivitamin, mineral supplements, thiamine and vitamin B complex must be given at appropriate doses.
Individual markers of nutritional status: Anthropometry is a good indicator of both health and nutritional status in individuals. It measures individual size, shape, and composition of human body and predicts health and survival. The common techniques are body weight, body mass index, mid-arm muscle circumference, and skin fold thickness. Body weight is a measure of total weight including muscle, fat, water, and bone. Body weight alterations reflect nutritional status and are an important assessment tool. Underweight as well as overweight status has an important outcome in mortality and morbidity following burn injuries. Body mass index (BMI) is weight of the person in kilograms divided by height in meter square. It is a measure of body fat stores, a useful tool to classify subjects into weight categories and its relationship to health risks. Muscle mass is not taken into account in calculation of body mass index. It is not ideal for children. Their weight needs to be monitored using growth charts.
Growth charts: Adequacy of nutritional status in infants and children can be studied using anthropometric methods. Adequate growth is the single most important measure of nutritional status in infants and children under 5 years old. Weight for age, height for age, and weight for height calculation are used to identify the presence of under nutrition in children.
- Height for age is the measure of linear growth; growth failures of long duration or stunting are measured.
- Weight for height is sensitive factor in acute growth disturbances. It reflects development of proper body proportions and associated harmony of growth. It helps in detecting wasting.
- Weight for age is for identification of underweight children.
Various standards are compared to international reference standard populations by NCHS/WHO (National Centre for Health Statistics/World Health Organization). To be classified with wasting, underweight or stunting, the child must be 2 SD or more below the compared standards.
Skin fold thickness is a simple test to study the relationship between subcutaneous fat and total body fat. Yuhasz skinfold test uses six sites for measurements. Most other tests use only three or four sites. Pinch a fold of skin with subcutaneous fat between a pair of skinfold calipers and measure the thickness (adiposity). The common areas of skinfold measurements are triceps, abdominal, chest wall, midaxillary, subscapular, suprailiac and thighs. Waist circumference is an important tool in the classification of obesity and predicts risk of obesity formation. It is an accurate measure of central obesity. Increased risk of diseases like Type 2 diabetes, hypertension, high cholesterol, and associated coronary heart disease (CHD) is predicted with a waist circumference of >94 cm in men and >80 cm in women. Waist to hip ratio predicts heart diseases and risk of mortality and has little advantage over waist circumference.
Biochemical and hematological values have limited value in assessment of nutritional status. Profound nutritional depletion greatly alters the physiological chemistry. They are prone for changes on a daily basis and homeostatic mechanisms frequently try to compensate such changes. These parameters are modified by disease conditions and nutritional status measurements are inaccurate. Estimations of vitamins, minerals, and trace elements show only depleted levels in severe nutrient deficiency, for example, iron, zinc.
Nutritional management considerations in pediatric patients: “Extensive thermal injury elicits the most profound response to stress that the human body is capable of generating.” Pediatric patients with critical burn injuries have increased nutritional requirements due to losses of protein and trace elements through wound exudation. Repeated episodes of fasting for surgical procedures and dressing changes, pain and nausea make pediatric burn patients nutritionally more vulnerable. Psychological distress in children and side effects of medication also modify nutrition in children. The top priority in children and adolescents with burn injuries is to achieve normal growth and development. Protein, energy, vitamins and minerals supplementation in adequate quantities is crucial to good wound healing, to reduce risk of infections, breakdown of wounds and grafts. Adequate nutrition reduces respiratory complications and shortens hospital stay duration and make sure the child maintains a normal growth.
| Burn management in children and adults—key points:|| |
- Children require more fluid than adults as fluid losses are higher in children. Also, they have nearly three times the body surface area (BSA) to body mass ratio compared to adults.
- High surface-to-volume ratio and low-fat mass in children make them prone to develop hypothermia that increases the risk of increasing the depth burn and hypothermia must be avoided.
- Adequate fluid resuscitation, prevention of hypothermia, pain control, and optimal blood glucose level must be the goal in pediatric burn patients.
- Further increases in metabolic rate are due to non-shivering thermogenesis of temperature regulation.
- Urinary output is the most reliable and sensitive indicator of fluid resuscitation in children and fluid resuscitation must be more precise.
- Pain management in burn injured children is crucial for hemodynamic stability and nutritional therapy. Children cannot express pain. It is safer to start with small doses of Morphine at 0.1 mg/kg body weight by intravenous route and the dosage can be increased based on hemodynamic stability and assessment of respiratory status.
| The aims of nutritional intervention for pediatric burn injured patients are:|| |
- Attain normal growth and development especially in children.
- Maintain lean body mass.
- Optimize wound healing process and good take of skin graft.
- Modulation of immune system.
- Correction of preexisting nutritional deficiencies.
- Integrity of gut and bowel function must be maintained.
Energy requirements in children: Indirect calorimetry is ideal for estimation of energy requirements in pediatric burn patients. Assessment is done on hospitalization and then twice weekly till the wounds are all healed. The total energy needed is calculated by RMR multiplied by a factor of 1.3 (20%–30%). For patients with <30% TBSA burn, adequate energy is provided by using dietary reference intakes (DRI) initially according to the age group. For greater than 30% TBSA burns following formula is used [Table 8] (BSA—body surface area: BSAB—body surface area burned).
Energy requirements are calculated depending on age, weight, and height, TBSA burn injury and depth of thermal injury. Burn dietitian calculates the requirement and must continually reassess the therapy. In the first 24 h following injury, energy requirements does not rise above the estimated average requirement (EAR). Estimated average nutritional requirement can be achieved easily in patients with smaller percentage of burns. For children, use the EAR for their age and weight. For children with burns >10%–15% body surface area, the Hildreth formula is currently the standard formula used for calculating energy requirements.
Hildreth equation: TBSA can be calculated using the surface area nomogram or the following formula [Table 9]: Total Body Surface Area = √ Height (cm) × weight (kg)/3600. TBSA is then used to calculate individual energy requirements.
Protein requirements for minor burns: Normal protein requirements for age are sufficient for patients with minor burn injuries. Protein requirements are higher in the moderate/major burn patients.
- There is a massive protein loss through burns exudates. Protein is needed for skin repair so requirement is high [Table 10].
- Burn injury is associated with deterioration in nutritional status of patients admitted to the hospitals. Moderate and severe malnutrition is seen in 20% of the patients within the two weeks following burn injury (weight for height scores).
- About a third of the patients lost more than 10% of their weight in two weeks, a very rapid weight loss compared to what is expected in pediatric burn injury patients.
- Age and preburn nutritional status have a significant role in deterioration of nutritional status in pediatric burn patients. Growth deficiencies can be identified by using tools like mid-upper arm circumference measurement.
Baseline blood measurement of nutritional elements (U and E) to detect abnormalities of blood chemistry, primarily renal function and hydration are done. Serum albumin, CRP, liver function tests, FBC, phosphate, calcium, vitamin D, and magnesium are the basic investigations required. Patients suffering from moderate and severe burn injuries must check trace element status on a weekly basis until return to normal range.
Nonprotein calorie to nitrogen (NPC:N) ratio: Ideally NPC:N ratio should at 150:1 for small area burns and 100:1 for larger area burns. Calculation of nonprotein kcalories to nitrogen ratio (NPC:N):
- Total nitrogen in grams supplied per day is calculated (1 gN = 6.25 g protein).
- Total nonprotein kcalories is divided by grams of nitrogen.
NPC: N Calculation example: 80 grams protein - 2250 nonprotein kcalories per day. 80 g protein/6.25 = 12.82250/12.8 = 176 NPC:N = 176:1.
- In the most severely stressed patients at 80:1
- In severely stressed patients at 100:1
- Unstressed patient at 150:1
Micronutrients supplementation in pediatric burns: Antioxidantvitamins like A, C, and E and trace elements beneficial effects on wound healing and immunity. Trace elements are mostly lost through large volume exudates in burn wounds. Micro-nutrients cannot be synthesized in the body and decreased levels are identified in the postburn injury. Various metabolic activities such as oxidative stress, collagen cross linking in wound healing, and immune functions are related to presence of many enzymes. Micronutrients and trace elements are important components of most enzymes.
It is recommended trace elements administered immediately within the first few hours following burn injury (Berger). High dose of trace elements supplementation reduces the length of hospital stay, infection rates, and reduces the number of graft procedures required and supports wound healing. ESPEN recommends administration of trace elements in higher doses in postburn periods. Depending on TBSA of burn, trace elements should be prescribed for particular duration.
- 20%–40% burn injury—for 7–8 days
- 40%–60% burn injury—for 2 weeks
- >60% burn injury—for 30 days
Calcium and vitamin D requirements in pediatric burn patients: Major burn injuries in children cause dysfunction of calcium and vitamin D homeostasis mechanisms. It is associated with osteoblast apoptosis—an increase in bone resorption and urinary calcium wasting. Synthesis of normal quantities of vitamin D3 is not possible in the burnt skin, and this decreases the levels of calcium and vitamin D. Homeostasis of calcium, phosphorus, and skeletal bone integrity depends on vitamin D levels and also has significant metabolic effects on serum calcium, magnesium, and phosphorus. Almost 97% of pediatric age group burn injury patients have low vitamin D (serum 25-hydroxyvitamin D) levels at 1 year following major burn injuries. Administration of vitamin D3 beyond the acute phase of burn corrects the abnormal serum levels and avoids morbidity. Vitamin D3 reduces the risk of postdischarge fractures in children. It is important to monitor the bone health in pediatric patients in the postburn follow-up visits. Both vitamins D3 and D2 (100 IU/kg) supplementation help critically ill pediatric burn patients to sustain growth.
Enteral feeds in pediatric burn patients: In the presence of functioning or even partially functioning gastrointestinal tracts enteral feeding is the route of choice for the nutritional support in pediatric burn injury patients. Enteral feeds and supplementscontain additional vitamins and minerals, and this may be sufficient to meet the child’s increased requirements with out the need for supplementation. Children with major burn injuries need protein and energy (calories) requirements 2–3 times normal and the requirements for vitamins and minerals are also increased.
| Following are the reasons for failure to eat enough by children with burn injuries:|| |
- The shock and trauma of the burn
- Drowsiness from drugs, fever, pain, and fear
- Related to burn washing and dressing
- The hours of fasting for baths and graft operations
- Time spent in physiotherapy or at other appointments
- Being in hospital itself in unfamiliar surroundings and with unfamiliar foods
Special attention must be focused on children to meet with their nutritional needs. It is difficult to manage children during the nutritional supplementation period; they need to eat and drink more to make up for the increased energy and protein needs. Dietitian advises on the best feeding plan for the inpatient child. Discussion with the dietitian and nursing staff regarding the various aspects of nutrition issues with the child will help mothers to continue the treatment at home.
Guidelines to encourage children with burn injuries to eat and drink include are as follows:
- Well-planned healthy food must be given to all throughout the day. Ideally, small and frequent amounts of food must be given, aim for 5–6 small meals or snacks each day.
- Food that is familiar to the child must be given and encourage foods that the child can manage.
- Home-cooked meals and the child’s favorite foods supplied from home will be accepted better.
- For babies and toddlers, milk and nutritious drinks are very important. Plan them during each meal and snack times, especially when children are not eating much.
- Take help from the dietitian regarding the best choice for the child. A positive attitude when offering food and drink to the child will make them accept food better.
- Positive praise, no matter how small as your child eats or drinks will encourage to take more.
- Make enjoyable and interactive for your child during meal and snack times.
| Key points:|| |
- Tentrini range is not on the starter regime, choose Nutrini up to 21 kg and Nutrison if >21 kg. MF = multifiber. Most feeds are available with or without fiber. All the earlier feeds contain cow’s milk protein. Check for any allergies before commencing a feed [Table 12].
- If the child is on a specialized formula, the child seeks dietetic advice for patients with major burns and an additional protein may be provided by a supplement or specialized feed. If a patient is also receiving larger than normal volumes of feed in order to meet higher calorie requirements, it may be necessary to review electrolyte content.
- A feed that is designed for a younger age group (e.g., Tentrini range, instead of Nutrison) may be needed to avoid excess electrolytes.
- Micronutrients content should be reviewed and compared to reference nutrient intakes (RNIs) if excessive feed volumes or inappropriate for age feed is being provided.
- It is a good practice to regularly monitor for signs of gastric intolerance when a patient is receiving enteral nutrition.
- A hydrolyzed feed may be indicated if a whole protein feed is not tolerated.
Psychological support in pediatric burn patients: In acute phase, psychological stress often accompanies the physical damage of severe burn injury. Children are prone to develop internalizing behavioral changes such as anxiety and withdrawal. They may develop externalizing behaviors characterized by oppositional defiant disorder. They are the healthy coping mechanisms that help children deal with their situation. Dysfunctional behaviors or attitudes also develop in children, and they must deal with a lot of complications. They develop anxiety and post-traumatic stress disorder (PTSD) symptoms. They develope difficulty with social interaction, issues related to self-esteem, or problems with body image due to scarring and functional deficits as a result of the burn injury. Negative psychosocial outcomes are common in nearly 15%–20% of children as a result of burn trauma. Pediatric survivors and their families of burn injury require professional psychological support to recover from the burn-related psychological problems.,
| Unique considerations in pediatric burn care—key points:|| |
- Children with partial-thickness burns of greater than 10% TBSA, burns of the face with or without inhalation injury must be referred and treated in a burn care facility. The other indications include burns involving head, neck, hands, feet, genitalia, or electrical or chemical burn injuries. Burn center referral criteria for pediatric patients include intentional injury and suspected child abuse.
- Children have limited physiological reserve, and fluid resuscitation has to be precise. Lund–Browder chart is used to estimate TBSA and fluid is calculated at 2 mL times percent of TBSA times weight in kilograms.
- Estimation of pediatric energy expenditure is done with Schofield equation.
- Children have small airways and with little suspicion of inhalation injury they must be intubated immediately using a low-volume cuffed endotracheal tube.
- Adequate sedation and analgesia for dressing changes reduce pain and psychological trauma.
- Institution of nutrition therapy at an early period is essential.
- Physiologic and psychosocial problems in children are different from adults.
Child psychiatry, child life specialist, and therapists will help cope up with the situation. Counseling is required for the child, caretakers, and family members.
Parenteral nutrition (PN) is the intravenous route of feeding. It does not involve the natural process of eating and digestion, although it bypasses the gastrointestinal tract [Table 13]. Ideal candidates for parenteral nutrition are patients at risk of malnutrition with depleted reserves and who fail to achieve required nutrition by oral or enteral routes. Nutritional formulae are available with glucose, salts, amino acids, lipids, with added vitamins, and dietary minerals in various combinations and proportions. It can be short-term or long-term parenteran nutrition. The TPN may be avoided as many patients receiving parental nutrition (PN) will continue some level of oral intake.
PN is instituted in consultation with the multidisciplinary team when EN is contraindicated or the patient is not able to meet the needs due to ileus, small bowel obstruction, prolonged malabsorption, or intolerance to EN. There are different approaches to implementation of PN [Table 14]. Complications of PN are metabolic or catheter related. Skin loss and thrombotic complications carry significant mortality.
Patients requiring PN should be referred to dietitian for recommendations regarding nutritional supplementation [Table 15]. Provision of trophic feeds maintains integrity of the gut and also reduces bacterial translocation, should be given where possible. Approximately 50% of total energy should be from carbohydrates sources for all burn patients. The recommendations shown in [Table 14] are made in relation to the age group of the patients.
Total parenteral solutions are available in different composition of its constituent nutrients content. Both clinical and laboratory monitoring are important in deciding about the type of the required supplementation [Table 16].
| Investigations to be done in patients who are receiving TPN:|| |
- Blood glucose monitoring every 4–6th hourly.
- Assessment for the risk of refeeding syndrome must be done daily.
- Transferrin and C-reactive protein (CRP) estimation should be done once or twice weekly.
- Evaluation of liver function, lipid profile, and calcium along with an estimation of albumin and prealbumin values must be done on weekly twice basis.
- Estimate serum levels of zinc, iron, selenium, and copper levels every 2–4 weeks.
- Full blood count and serum magnesium and phosphate levels estimation. Manganese and 25 OH vitamin D levels should be done at 3–6 monthly intervals.
Complications: TPN predisposes to various complications as it entirely bypasses the gastrointestinal tract and natural ways of nutrient absorption: Infection: Approximately 15% of patients get infective complications due to TPN and death is due to septic shock. Infected chronic intravenous access catheter is a common cause of death. Hospital-acquired infection (HAI) is a major complication of PN and every effort should be made to avoid HAI. Blood clots: Chronic IV access leads to thrombus formation and may develop pulmonary embolism leading to death. Fatty liver and liver failure: Linoleic acid is an omega-6 fatty acid component of soybean oil, a rich source for calories. It causes fatty liver and lead to liver failure. Hunger: Patients on TPN develop intense hunger pangs as they are not eating, even though the body is getting fully nourished. Cholecystitis: Complete disuse of gastrointestinal tract results in bile stasis in gallbladder and formation of sludge that takes 4 weeks to disappear after starting normal oral diet. Risk of acute cholecystitis occurs. Exogenous cholecystokinin (CCK) and amino acids prevent sludge formation. Steatohepatitis, steatosis, cholestasis, and cholelithiasis are the various hepatobiliary dysfunctions that are common. Gut atrophy is common in patients on TPN and are not taking food by mouth for prolonged periods of time. Other complications are related to catheter or metabolic causes. Catheter insertion has risk of pneumothorax, accidental arterial puncture, and catheter-related sepsis. Hypophosphatemia, hypokalemia, and hypomagnesemia of refeeding syndrome are the main metabolic-related complications. Hyperglycemia occurs with abrupt cessation of TPN.
Role of nursing staff in nutrition of burn patients: Nursing personnel play a central role in wide spectrum multidisciplinary care of burn injury patients. Their role begins with the resuscitation of the patient and proceeds through various stages of recovery of the patient. They coordinate with various departments and specialties for the benefit of the patient. They take part in infection control and care of the wound. They identify and take care of nutritional care of burn injured patients. Insertion and stabilization of NGT, monitoring the pH, feeding tube placement check by radiology, check tube clogging, and tube patency maintenance protocols are responsibilities of nursing staff [Figure 4]. pH checking: Correct tube placement in the stomach is confirmed by appearance of aspirate and pH testing. Confirm a position of feeding tube by radiology when appearance of the aspirate is not suggestive of gastric or intestinal origin or has a pH between 5 and 6 and when aspirate fluid pH is >6 with no aspirate despite other measures. Feeding position: The nursing staff make sure the position of the patient during feeding. During feeding procedure, it is recommended to keep a semirecumbent position or an elevation of at least 30 degrees. Maintaining the position for at least 1 h after feedings to prevent complications of aspiration is required. The speed and volume of feeding affect intragastric pressure and develop gastroesophageal reflux (GER). Administration of medications, prevention of diarrhea, and monitoring and management of gastrointestinal tolerance are important role played by the nursing staff.
Gastric residual volume (GRV) is an important measure in patients on continuous feeding protocols. It should be checked every 4–8 h as a routine and before start of each intermittent feeding.
- When GRV reading is greater than 200 mL, it indicates a careful bedside evaluation to be done immediately. Adjustments in appropriate feeding method and feeding volume are necessary.
- Abdominal distension, absence of bowel sounds, and the presence of nausea and vomiting are the clinical examinations required. With increased GRV levels a change in feeding strategies must be planned.
- A series of GRV is more important and informative than an isolated high level of GRV.
- Returning and not returning gastric residuals do not show significant differences between them.
| Nursing interventions—key points:|| |
- Nasogastric tube for gastric decompression is essential in patients with greater than 20% TBSA burns.
- Abdominal girth measurements and bowel sounds are checked every 8 h.
- Color, quantity, and pH of NG aspirate is checked and monitors stool for hemocult blood.
- Stress ulcer prophylaxis is an important consideration.
- Enteral feeding is initiated and evaluates the tolerance to the feeds.
- High-calorie/protein supplements are used as advised by dietician.
- Record of all oral intake and calories administered must be documented.
- Activities and interventions must be scheduled in such a way as not to avoid interrupting feeding schedules.
- Weight measurements of the patient are done on a daily or biweekly protocol followed in the burn center.
Percutaneous endoscopic gastrostomy (PEG) tube: Alimentation and decompression are the two important aspects of a successful management of nuitrition in severely burned patients. The aim is to maintain their caloric balance. Conventionally used NGT causes discomfort and other complications. In nonburn patients in ICU, PEG has been used successfully for nutritional access. In patients with associated inhalation injury or dysphagia, PEG tubes are used as nutritional portal. Tube placement through partial or full-thickness burn areas does not have an increase in wound complications. The advantages of PEG tubes are that feedings are tolerated well, and no major operative or wound complications with no mortality related to the tubes. A modified tube with two exchangeable lumens of sufficient diameter has improved performance of feeding. It has been introduced exclusively for use in burn patients.
Challenging aspects of burn nutrition are nonavailability of indirect calorimetry. Present challenges and possible measures that can be taken in developing countries include making them available. Biomarkers of illness can improve in molecular basis of different pathological conditions. Extensive search is needed in the field of glycemic control, pharmaco-nutrition, and immune-nutrition. There is a need to carry out randomized control trials and studies to make guidelines, improve “total burn care” concept, and improve funds that are available for health services.
Nutrition management after discharge: It is mandatory that the patients must continue with adequate nutrition therapy program following discharge from the hospital. It is important to maintain the benefits of nutrition therapy gained during hospitalization. Hypermetabolic state persists more than a year or two following burn injury. Diets with high protein and more caloric are necessary for about a year after discharge. Resistance exercises are essential to maintain muscle mass and increase the strength. Physicians and dietician advise the patients regarding the nutrition therapy to be followed at home. They must regularly check weight to make sure they maintain their weight. Oxandrolone must be continued in the outpatient setting. The optimum duration of such therapy is still a matter of discussion. Nutritional assessment is a routine and a valuable exercise for follow-up patients.
Burn nutrition in a nutshell: (1) EN started within 24–48 h of burn injury has many beneficial effects on final outcome in patients and the method of choice. (2) Energy requirements are elevated and must be supplemented, but overfeeding is detrimental. (3) Administer proteins at 1.5–2.5 g/kg and maintain nitrogen: nonprotein energy ratio at 100:1. (4) Arginine is used for a short period and not for long-term use. (5) Glutamine must be substituted for its positive effects on the patients. (6) The need for micronutrients is also increased and uses parenteral route for trace elements replacement. (7) High-dose vitamin C administered in the initial fluid resuscitation phase helps reduce the volume of fluid requirements. (8) Every stage of patient care must be monitored and corrective steps must be taken early. (9) Progressive exercise program along with occupational therapy and good psychological counseling will support the patient get back to his job and to the society.
Burn rehabilitation: The aim of treatment of burn patients is to obtain an excellent functional recovery. From the day of burn it undertakes rigorous program to protect range of motion (ROM), strength, and flexibility. Preservation of ROM and skin integrity are the goals of the initial rehabilitation phase. A treatment plan based on patient’s individual needs is developed by a burn care therapist. Physical and occupational therapy started from the acute phase of burn injury is ideal. Patients must aim to maximize performance in ambulation and mobility. They must aim to achieve in activities of daily living, that is, bathing, dressing, and return to community activities as early as possible. Splinting and positioning regimes include supporting strategies such as regular and preemptive analgesia. Children require play therapies, distraction techniques, and rewards (i.e., sticker charts) for improving their performance. Ongoing education, positive reinforcement, and consistency in care of the patients are the essential components for good outcomes and early rehabilitation of burn injury patients. Splinting and positioning regime issues are recorded and reported back to physiotherapy and occupational therapy for required alterations to regimes to be initiated. The nursing staffs coordinate with the entire burn care team ahd help in rehabilitation of patients with burn injuries.
“Quality of life” in burn injury patients: The final outcome of burn management depends on various factors such as severity of burn injury, individual physical characteristics, and quality of treatment received. Motivation on part of the patient and after care support received both from the family and community are also important factors. Physical and psychiatric morbidity depends on various factors such as severity of burn injury, treatment duration, surgical procedures, and associated pain. These factors are important for morbidity in patients and may affect the quality of life in burn injury patients. Depression is the most common psychological problem and PTSD is also seen in large percentage of patients. Patients may suffer from adjustment disorders, phobic anxiety disorder, acute stress reaction, substance use disorder, and somatoform disorders. Psychiatric care must be initiated at every stage of their burn treatment. This will be beneficial for better adjustment in life and may require years of supervised rehabilitation, reconstruction, and psychosocial support. Quality of life scale (QOLS) is measured by long-term results in relation to function and appearance. It measures three conceptual domains of quality of life, namely:
- Relationships and material wellbeing
- Personal, social, and community commitment
- Health and functioning
“Recent updates in critical care nutrition—challenges and solutions”: Nanotechnology has enhanced the potentials in research areas in nutrition: (1) Nanotechnology has helped in discovery of novel properties nutrients. (2) Characterization of properties of nutrients and their metabolites is made possible and nanotechnology has helped to quantify them. (3) It is possible to assess nutritional status by nanotechnology techniques and to target cells and compartments. (4) Nanotechnology-enabled targetted delivery of nutrients into cells and compartments have been developed. (5) New devices and hybrid structures are developed for pathway repairs by nanotechnology. Prevention and cure of nutrient deficiencies are in a more quantitative and timely fashion. (6) Possibilities to explore epigenetic studies have opened up. A special emphasis on methylation and folate and one-carbon metabolism is made possible by nanotechnology. (7) Critical cell nutrient signaling pathways are identified and it is possible to examine nutrients/metabolites as they modulate cell signaling pathways. (9) Effect of cell nutrient signaling on overall cell function can now be analyzed by the available nanotechnology methods.,
Nutritional Biomarkers are defined by Potischman as “any biological specimen that is an indicator of nutritional status with respect to intake or metabolism of dietary constituents.” It can be biochemical, functional, or clinical index of status of an essential nutrient or another dietary constituent. They are divided into three main classes, depending on the relationship between intake and biomarker:
- Recovery biomarkers development is based on physiological balance between intake and excretion. Total excretion of the marker over a defined time period is measured. They are best suited to estimate absolute intake. Urinary nitrogen and potassium are the recovery markers available.
- Concentration markers are based on the concentration of the respective marker. There is no information on the physiological balance of intake and excretion. As they correlate with intake, they are used to rank intake of specific nutrients.
- Predictive biomarkers were proposed by Tasevska et al. for biomarkers with incomplete recovery. They are stable and time-dependent high correlation with intake. These markers rank between concentration and recovery markers. They have an ability to estimate absolute intake. Urinary sucrose and fructose markers of sugar intake are the only predictive biomarker available.,
Future research: Nutritional biomarkers provide an objective assessment method for dietary exposure. They are important for future research into the association between diet and health. Development of new markers for the objective assessment of fruit and vegetable intake is underway. Metabolomics is a new technology for development of new biomarkers. New biomarkers must be validated using carefully controlled dietary intervention studies, and not just based on self-reported dietary data. From nutrition to nutrigenomics: Human Genome Project (HGP) is the study of interaction between genes and food bioactive compounds. Their interactions can positively or negatively influence an individual’s health. “Nutrigenomics” is an assessment of the interaction between genes and nutrients. Nutrigenomics is the study on the effects of the nutrients over the genome, proteome, and metabolome. Metabolomics is a “systematic study of the unique chemical fingerprints that specific cellular processes leave behind.” The chemical process involving metabolites is called metabolomics. It is a study of small molecule metabolite profiles. Collection of all metabolites occurs in a biological cell, tissue, organ, or organism. They represent the end products of cellular processes. The set of gene products being produced in cell, which represents one aspect of cellular function, is confirmed by mRNA gene expression data and proteomic analyses studies. Easy identification and study of the physiology of cell is possible by metabolic profiling. For better understanding of cellular biology, proteomic, transcriptomic, and metabolomic informations must be integrated which is a challenge in systems biology and functional genomics. Nutrigenomics is the integrated study and links genomics, transcriptomics, proteomics, and metabolomics to human nutrition. Many factors may influence metabolome. They are endogenous factors such as age, sex, body composition, and genetics; underlying pathology and exogenous factors that can modify are diet and drugs. Metabolic fingerprint is the biological end point decided by nutrients, nonnutrients, and metabolomics from the main diet. Large bowel microflora may act as endogenous or exogenous factor since it is a confounder of metabolic profiles.
| Discussion and Conclusion|| |
Burn care outcomes are variable due to multiple factors. Nutritional therapy affects the final outcome of burn care in relation to mortality and morbidity. Administration of nutrients starting from the early resuscitation period proves beneficial to the patient. Best results are achieved with early EN that modifies and attenuates the hypermetabolic, hypercatabolic state in burn patients. Macronutrients are supplemented in a ratio of protein: carbohydrate: Lipids 25:50:25. Glutamine administration at doses of 0.3–0.5 g/kg and omega-3 fatty acids are beneficial for development of immunity. They decrease the inflammatory response and prevent essential fatty acid deficiencies. Omega-6 fatty acids, when provided in large quantities, act as pro-inflammatory agent. Protein as a macronutrient has beneficial effects and glutamine is the amino acid of choice. Antioxidants can be given enterally and parenterally for their beneficial effects. Vitamins C and E decrease lipid peroxidation and improves wound healing. Zinc helps in recovery process following a burn. Selenium functions as activating glutathione peroxidase that is crucial in burn patients. Early EN with adequate supplementation of macronutrients, micronutrients, amino acid vitamins, antioxidants, and trace elements help in good wound healing and improved immunity and help in decreasing mortality and morbidity in critical burn injury patients.
Further research will improve the nutrition delivery system and bioutilization of the nutrients. Nanotechnology and recent genetic studies help in advances in nutrition management in general and particularly in burn injury patients and has improved the nutrition science. Future research will help burn patients achieve complete nutritional, functional, and psychological wellbeing withrehabilitation. Antioxidants, glutamine, and omega fatty acids need to be improved so that postburn morbidity and mortality are reduced. Development of better delivery systems of each of these components will help improve the outcome in burn patients. The recent advances in technology together with improved critical burn care will ultimately benefit the patients in the near future.
Financial support and sponsorship
Conflicts of interest
Author has no conflict of interest to declare. There was no industrial sponsoring of the guideline process.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12], [Table 13], [Table 14], [Table 15], [Table 16]