SEQUENTIAL-CHANGES IN THE METABOLIC RESPONSE IN CRITICALLY INJURED PATIENTS DURING THE FIRST 25 DAYS AFTER BLUNT TRAUMA

Background Understanding the changes in energy expenditure and body co mposition is essential for the optimal management of the critically in jured, yet these changes have not been quantified within the current c ontext of trauma care. Methods Ten critically injured patients (median Injury Severity Score = 35) had measurements of energy expenditure an d body composition as soon as they were hemodynamically stable and the n every 5 days for 21 days. Results Resting energy expenditure rose to 55% above predicted and remained elevated throughout the study period . Total energy expenditure was 1.32 X resting energy expenditure. Body fat was oxidized when energy intake was insufficient (r = -0.830, p < 0.02). Body water changes closely paralleled body weight changes and were largely accounted for by changes in extracellular water. Over the 21-day study period, there was a loss of 1.62 kg (16%) of total body protein (p < 0.0002), of which 1.09 kg (67%) came from skeletal muscle . Intracellular potassium was low (133 +/- 3 mmol/L, p < 0.02) but did not deteriorate further after hemodynamic stability had been reached. Conclusions These results show that the period of hypermetabolism las ts longer and the protein loss is greater in critically injured patien ts than previously thought. Most, but not all, the protein is lost fro m muscle. Fat loss can be prevented and cell composition preserved onc e hemodynamic stability is achieved.