NUTRITIONAL INFLUENCE ON THE RECOVERY OF (CO2)-C-14 IN CRITICALLY ILLTRAUMA PATIENTS

Several factors, including age, nutritional and metabolic status, and underlying-pathological conditions, should be considered in estimating the correction factor for labeled CO2 retention. We have evaluated th e nutritional influence of this correction factor in a group of severe ly injured (injury severity score = 33 +/- 5), hypermetabolic, and hig hly catabolic adult trauma patients. Primed-constant infusion of (NaHC O3)-C-14 was used, and the breath (CO2)-C-14 radioactivity was measure d. The experiment was conducted once in the fasting condition during t he early catabolic ''flow'' phase of injury and again during and after a week of intravenous feeding. The mean value of the (CO2)-C-14 recov ery (85.2 +/- 2.7%) in the basal fasting condition was higher than the value of 81% commonly used in normal subjects. During intravenous nut ritional support the recovery was 100.8 +/- 1.7%. Recovery of tracer i ncreased linearly with O-2 uptake and CO2 production. The linear expre ssion obtained between recovery and CO2 production could estimate the recovery within 3% in trauma patients, and that obtained by multiple r egression with CO2 production and O-2 uptake would predict the recover y within 1.5%.