Evaluation of Amino Acid Infusion preventive effect on Hypothermia during Spinal Anesthesia for Hip Arthroplasty

Background: Hypothermia increases bleeding during surgery, risk of ischemic heart disease and postoperative wound infection. Intravenous amino acid increases cell synthesis and produces heat. Our goal was evaluating of the effect of amino acid on intraoperative hypothermia under spinal anesthesia. Methods: This is a randomized, double-blinded clinical trial that 36 adults undergoing Hip Arthroplasty were randomly assigned into two groups of 18 each. One group received Amino Acids solution (Aminoven 10%) 500ml (240ml/h) throughout spinal anesthesia, and control group received saline solution. We measured core body temperature, MAP and HR each 10 minutes, and also postoperative shivering, blood loss, operation time, postoperative BUN and Cr were compared in two groups. Results: Throughout surgery, the reduction in core temperature was more in the control group than the amino acids group (statistically not clinically). The decrease in core temperature was significantly larger in the controls (0.96°C ± 0.7°C) than in the amino acid patients (0.94°C ± 0.4°C), (P value= 0.02). Postoperative shivering was 73% in the controls regarding 11% in the amino acids patients. Overall, there were no significant statistical differences between other variables that we measured in two groups of patients. Conclusion: Amino acids infusion during spinal anesthesia exerted a thermogenic effect. Our findings showed hypothermia was less in the aminoacid group, and also postoperative shivering was more in the control group.