ABSTRACT
Intravenous amino acids infusion during general anesthesia prevents decreases in core temperature resulting from increased energy expenditure and heat accumulation. Mild hypothermia may increase surgical bleeding. We studied the effect of amino acids infusion on changes in core temperature and blood loss during spinal anesthesia in patients undergoing hip surgery. Fifty patients were divided into two equal groups. Group 1 patients received an amino acids infusion at a rate of 2 ml /kg/ hr., corresponding to 4kjkg-1h-1, started 1 hr before spinal anesthesia and two hours during surgery. Group 2 patients received normal saline for the same period. Mean blood pressure, heart rate, tympanic membrane core temperature, forearm-fingertip temperature gradient and mean skin temperature, coagulations profile were monitored during the study period and blood loss was measured. Changes in mean arterial pressure and heart rate did not differ significantly between the two groups during the study period. Mean final core temperature 120 min. after induction of spinal anesthesia was 34.37 [SD 0.37] °C in the saline group and 36.02 [SD 0.21]°C in the amino acid group [p < 0.05] The thermal vasoconstriction threshold was increased in the amino acid group [36.1 +/- 0.1 °C] compared with the saline group [34.0 +/- 0.1 °C]. Blood loss during surgery was significantly larger in the saline group [704.88 +/- 175.9 ml] than in the amino acids group [553.2 +/- 107.14] [p < 0.05]. Platelet counts decreased significantly in both groups immediately and first day after surgery [p < 0.05]. However, there were no differences in coagulation values between the two groups. The amino acids infusion before and during spinal anesthesia was able to prevent the occurrence of intraoperative hypothermia and reduces blood loss without significant effect on coagulation profile