Intraoperative fluid management influences carbon dioxide production and respiratory quotient

The authors studied the effects of glucose-containing versus nonglucose-containing solutions for intraoperative fluid management on CO2 production and respiratory quotient (RQ) during the first postoperative hour. Three groups of patients were studied. Patients in Group 1 received normal saline during the operation and first postoperative hour; patients in Groups 2 and 3 received 5% glucose in half normal saline during the operation. This solution was continued through the postoperative period for patients in Group 2, while patients in Group 3 were given normal saline postoperatively. All patients received 500-1000 ml during the first hour and 500 ml/h thereafter. During the first postoperative hour, CO2 production and O2 consumption were measured every 15 min. RQ was significantly higher in Group 2 (0.93 +/- 0.01) than in Group 1 (0.77 +/- 0.01) (means +/- SEM, P less than 0.05). CO2 production was about 20% higher in Group 2 than in Group 1. There were no differences in O2 consumption between Groups 1 and 2. In Group 3, RQ decreased significantly (from 0.97 +/- 0.04 to 0.87 +/- 0.03) during the first postoperative hour but remained higher than in Group 1. The authors conclude that intraoperative administration of glucose-containing solutions increases RQ postoperatively; this effect can be reversed partially by changing to glucose-free solutions in the postanesthetic period.