AJP - Endocrinology and Metabolism, Vol 260, Issue 1 E118-E125, Copyright © 1991 by American Physiological Society
Effect of surgical injury and intraoperative hypothermia on whole body protein metabolism
D. P. Taggart, D. C. McMillan, T. Preston, A. Shenkin, D. J. Wheatley and H. J. Burns
Department of Cardiac Surgery, Royal Infirmary, Glasgow, United Kingdom.
Whole body protein turnover and urinary nitrogen and 3-methyl-L-histidine
(3-MH) excretion were measured before and after cardiac surgery using
cardiopulmonary bypass in 20 male patients randomized to an intraoperative
blood temperature of 28 or 20 degrees C. Rates of whole body protein
synthesis (WBPS) and breakdown (WBPB) were determined from the 15N isotopic
enrichment of urinary urea, ammonium, and from a calculated end-product
average (EPA) after a primed 24-h infusion of [15N]glycine. In the
postoperative period, there was a 40% increase in median nitrogen excretion
in the 28 degrees C group (P less than 0.03) and a 22% increase in the 20
degrees C group (P = 0.10). There was a 79% increase in the median
postoperative 3-MH excretion in the 28 degrees C group (P = 0.01) and a 66%
increase in the median postoperative 3-MH excretion in the 20 degrees C
group (P less than 0.01). Postoperatively, there was a 23% fall in the
median value of WBPS in the 28 degrees C group (P less than 0.01) and an
11% fall in the 20 degrees C group [not significant (NS)] measured by 15N
enrichment of urinary urea. In contrast, when WBPS was measured from
isotopic enrichment of urinary ammonium, there was an increase in the
median value of the postoperative rates of WBPS in both groups, by 20% in
the 28 degrees C group (P = NS) and 29% in the 20 degrees C group (P =
0.03). There was no significant change in the rate of WBPS and WBPB, judged
by the postoperative EPA in either group.(ABSTRACT TRUNCATED AT 250 WORDS)
