Amino acid infusions started after development of intraoperative core hypothermia do not affect rewarming but reduce the incidence of postoperative shivering during major abdominal surgery: a randomized trial

Purpose Previous studies have demonstrated that amino acid infusions exert enhanced thermogenic effects during general anesthesia. This study was conducted to investigate whether amino acid infusions started after development of intraoperative core hypothermia can accelerate rewarming. Methods Twenty-two patients scheduled for major abdominal surgery were included in this study. When tympanic temperature reached 35.5°C, patients were randomly assigned to receive amino acids (amino acid group; n = 11) or saline (saline group; n = 11). A continuous infusion of a mixture of 18 amino acids or saline was started at 200 ml h −1 . Tympanic, forearm, and digit temperatures were recorded. Forearm minus fingertip skin-surface temperature gradients (temperature gradient) were calculated. Postoperative shivering was also evaluated. Results Tympanic membrane temperature and temperature gradient were similar between the two groups at each time point during the study period. Temperature gradient at extubation in the amino acid group was significantly lower than in the saline group although tympanic temperature at extubation was similar between the two groups. Postoperative shivering score was significantly lower in the amino acid group than in the saline group. Conclusions Amino acid infusions started after development of intraoperative core hypothermia failed to accelerate rewarming. However, amino acid infusions reduced the incidence of postoperative shivering. Use of amino acid infusions to reduce thermoregulatory vasoconstriction at emergence might contribute to a decrease in the development of postoperative shivering.