ANTIPYRINE CLEARANCE IN SURGICAL PATIENTS MAINTAINED ON HYPOCALORIC PERIPHERAL PARENTERAL-NUTRITION

Background: Antipyrine clearance (CL(AP)) constitutes a sensitive indi cator of hepatic microsomal enzyme activity providing specific informa tion on hepatic function. The purpose of this study was to evaluate th e influence of hypocaloric peripheral parenteral nutrition on CL(AP) i n patients receiving nutrition support after elective surgery. Methods : CL(AP) was measured in 15 patients before elective gastrointestinal surgery and 6 days after the surgery. Antipyrine (1 g) was administere d orally, and CL(AP) was determined by the one-sample method. Subjects received a postoperative 786 kcal/d regimen providing 66 g of amino a cid per day and 133 g of glucose per day for 5 days. Nutritional statu s was evaluated by anthropometric parameters. A control group of 15 pa tients received no postoperative hypocaloric peripheral parenteral nut rition but received conventional fluid therapy Results: Mean CL(AP) wa s increased by 61% (0.66 +/- 0.06 mL/min.kg(-1) body wt vs 0.41 +/- 0. 05 mL/min.kg(-1) body wt in the preoperative period; p <.001), and ant ipyrine half-life was reduced by 42% (10.9 +/- 1.0 hours vs 18.9 +/- 2 .0 hours; p <.001) after 5 days of hypocaloric peripheral parenteral n utrition. No significant modification was shown among control patients in CL(AP) (0.54 +/- 0.07 mL/min.kg(-1) body wt vs 0.46 +/- 0.05 mL/mi n.kg(-1) body wt in the preoperative period) or in antipyrine half-lif e (14.0 +/- 1.4 hours vs 16.5 +/- 1.8 hours). No significant correlati on was observed between CL(AP) changes and those for the nutritional s tatus of the patients. Conclusions: The results of our study indicate that oxidative drug-metabolizing capacity is increased in surgical pat ients maintained on hypocaloric peripheral parenteral nutrition. Clini cians should be conscious of the potential of this effect for altering the efficacy or toxicity of many therapeutic agents.