EFFECT OF MAJOR ABDOMINAL OPERATIONS ON ENERGY AND PROTEIN-METABOLISMIN INFANTS AND CHILDREN

Purpose: The authors attempted to test the hypothesis that infants and children increase whole-body protein flux and energy metabolism durin g the early postoperative period. Methods: Ten infants and children (a ge range, 2 days to 3 years; weight range, 1.5 to 14.2 kg) who had und ergone a major operation were studied. Anaesthesia was standardised, a nd operative stress score (OSS) recorded. Patients were studied for 4 hours preoperatively and for the first 6 hours after surgery. Respirat ory gas exchange was measured by computerised indirect calorimetry. Th e components of whole-body protein turnover were estimated by giving a n intravenous infusion of [1-C-13]leucine, and by measuring the isotop ic enrichment of plasma [C-13]alpha-ketoisocaproic acid by gas chromat ograph mass spectrometry and (CO2)-C-13 enrichment by isotope ratio ma ss spectrometry. Results: Median duration of the operation was 73.5 mi nutes (range, 28 to 285 minutes) with a OSS of 8 (range, 7-17). There were no significant differences in oxygen consumption and resting ener gy expenditure between the two study phases. The respiratory quotient (RQ) fell from a preoperative value of 0.92 (range, 0.81 to 1.08) to 0 .89 (range, 0.79 to 0.95) postoperatively (P=.04). The authors found n o significant differences in the rates of whole body protein flux, pro tein synthesis, amino acid oxidation, and protein degradation between the study phases. Conclusions: Infants and children do not increase th eir whole-body protein turnover and metabolic rate after major operati ons. The observed decrease in RQ reflects mobilisation of endogenous f at. We speculate that the lack of catabolism observed in children is c aused by a diversion of protein synthesis from growth to tissue repair . Copyright (C) 1998 by W.B. Saunders Company.