Nutritional and Pharmacological Modulation of the Metabolic Response of Severely Burned Patients: Review of the Literature

Our understanding of the metabolic changes associated with starvation, stress, and sepsis has deepened over the past 20 to 30 years, and along with this came a greater appreciation for the importance of timing, composition, and route of administration of nutritional support to the trauma patient. Severe burn patients are some of the most challenging critically ill patients with an extreme state of physiological stress. Severe burn injuries produce a hypermetabolic response characterized by protein and lipid catabolism, total body protein loss, muscle wasting, peripheral insulin resistance, increased energy expenditure, and stimulated synthesis of acute phase proteins, mainly in the liver as well as in the intestinal mucosa. No other single insult results in such an accelerated rate of tissue catabolism, loss of lean body mass, and depletion of energy and protein reserves. Severely burned patients may have multiple-system organ failure with life-threatening complications requiring a complex interaction of surgical, medical, and critical care and rehabilitation approaches for management. Treatment of patients with extensive burns remains a tremendous challenge. Control of wound sepsis, decreased hospital stay, and increased survival have been the result of early burn wound excision and wound closure, however, and many problems faced by the burn patient remain unsolved, including control and treatment of the hypermetabolic response, which can be extreme. Extensive thermal injury is followed by a severe systemic metabolic response that consists of an early “ebb” phase and a later “flow” phase. The “ebb” phase lasts for two to three days and is characterized by a decreased cardiac output and metabolic rate. The “flow” phase begins on day 5 after injury and is characterized by a hyperdynamic circulation and an elevated hypermetabolic rate. A significant proportion of the mortality and morbidity of severe burns is attributable to this ensuing hypermetabolic response, reAnnals of Burns and Fire Disasters vol. XXI n. 2 June 2008