Amino acids versus magnesium sulfate infusion for controlling postoperative shivering in patients undergoing percutaneous nephrolithotomy surgery: a randomized clinical trial.

Background: General anesthetics disrupt the thermoregulatory mechanisms by reducing vasoconstriction and shivering thresholds. Postoperative shivering is a challenging anesthesia-related complication with an incidence range of 20-70%. Amino acids that induce thermogenesis and magnesium sulfate are centrally acting mechanisms that could minimize shivering. Thus, this trial was designed to compare the effect of amino acid versus magnesium sulfate infusion on postoperative shivering in patients undergoing elective percutaneous nephrolithotomy (PCNL) surgery under general anesthesia.

Methods: Eighty adults, American Society of Anesthesiologists I and II patients, were randomly assigned into one of two groups. Group A received general anesthesia and perioperative IV amino acid infusion. Group M received general anesthesia and perioperative IV magnesium sulfate infusion.

Results: There was a statistically significant difference in shivering score, which was lower in group A than M (0.8±1.1 versus 1.5±1.3; P value=0.01). The incidence of postoperative shivering was lower in group A (4 [10%]) versus (11 [27.5%]) in group M. A less decrease in the core intraoperative temperature (Celsius) was observed in group A than in group M (35.5±0.2 versus 35.1±0.2; respectively, P<0.001) and at the end of surgery (36.1±0.3 versus 35.7±0.3; respectively, P<0.001).

Conclusions: Perioperative amino acids infusion is more effective and better tolerated than magnesium sulfate in preventing postoperative shivering in patients undergoing percutaneous nephrolithotomy surgery. Cost effectiveness should be kept in mind, and amino acids infusion should be reserved in high-risk surgeries for shivering.