Energy Expenditure and Protein Requirements Following Burn Injury

Abstract

Severe burn injuries have long been known to have a profound effect on metabolic equilibrium that can persist after resolution of the cutaneous injuries. Following burn injury, metabolism is a dynamic state resulting in the need for frequent interval reassessment over the course of the care continuum. The acute phase of injury transitions to chronic alterations in macronutrient utilization characterized by futile energy cycling and disproportionate catabolism of skeletal muscle. Protein supplementation appears to be preferentially distributed to the burn wound rather than the skeletal muscle pool. Accurate assessment of caloric and protein requirements is extremely difficult in these patients but is an essential step in efforts to attenuate functional impairment. Indirect calorimetry should be utilized to determine caloric requirements, but trophic feeding strategies are preferred in the initial resuscitative phase to prevent overfeeding while maintaining enteric and immune function. Controversy persists regarding optimal protein targets, and weight‐based estimates remain the norm. Exogenous protein and caloric provision performed in isolation is insufficient to optimize outcomes and should be incorporated within a multidisciplinary approach to include muscle loading and pharmaceutical adjuncts.

The Link between Hypermetabolism and Hypernatremia in Severely Burned Patients

“…The differentiation between the two possible pathogeneses is not easy to make and was not the aim of this study. Exact protein requirements are quite unclear in the setting of burn injury and protein provision to the observed study patients was within normal ranges [15]. It is, however, worth mentioning that the high group also received more protein than the low group.…”

“…In burn injury, the systemic inflammatory, as well as systemic stress, response leads to hypermetabolism, catabolism and muscle wasting [14]. This hypermetabolic response is concomitant with increased energy expenditure and energy substrate release from muscle protein and fat stores [15]. Protein is catabolized, leading to muscle wasting and excessive urea generation [16][17][18].…”

Glucose Metabolism in Burns—What Happens?

“…There are two targets in the nutrition of severely burned patients, to provide enough nutrients in order to satisfy the increased caloric and protein requirements and to prevent the damage of the intestinal mucosa with subsequently augmented bacterial translocation from the gut to the blood. The caloric requirements in severe burns are dramatically increased [ 167 ] due to the hypermetabolic state [ 168 ]. The most accurate method to calculate the caloric need of a patient is indirect calorimetry, which is very difficult to use on a daily basis in burned patients [ 169 ].…”

Nutrition and Gastrointestinal Dysmotility in Critically Ill Burn Patients: A Retrospective Observational Study

“…Following fluid resuscitation, the gastrointestinal (GI) tract is particularly vulnerable, with gut edema potentially resulting in paralytic ileus 2 . EN initiated within 6–12 hours of admission has the capacity to maintain mucosal integrity and gut barrier function to reduce this occurrence 2,8,17,18 . In addition, delayed gastric emptying occurs in 10%–52% of burn patients 7 and significantly impairs nutrient delivery, particularly in the early phase of burn injury 2,19 .…”

“…2 EN initiated within 6-12 hours of admission has the capacity to maintain mucosal integrity and gut barrier function to reduce this occurrence. 2,8,17,18 In addition, delayed gastric emptying occurs in 10%-52% of burn patients 7 and significantly impairs nutrient delivery, particularly in the early phase of burn injury. 2,19 Using the surrogate measure of large gastric residual volumes (GRVs), delayed gastric emptying has been associated with adverse clinical outcomes, including an increased risk of bowel ischemia and ventilator-associated pneumonia.…”