Treatment with Ketamine and Pethidine Was Effective on Postoperative Shivering

Objective To compare the efficacy of low-dose of prophylactic ketamine with that of pethidine or placebo in preventing postoperative shivering. Methods A prospective randomized double-blind study involved 60 ASA I and II patients undergoing general anaesthesia. Patients were allocated at random to receive normal saline (Group N,n=20), 20mg of pethidine (Group P,n=20), or 0.5mg/kg of ketamine (Group K,n=20) intravenously 20 minutes earlier before completion of surgery. The anaesthesia was induced with propofol (2mg/kg), fentanyl (1μg/kg) and atracurium (0.6 mg/kg). It was maintained with 2-4% of sevoflurane. Tympanic temperature was measured immediately after the induction of anaesthesia, 30 minutes after induction and before administration of the study drug. An investigator, blinded to the treatment group, graded postoperative shivering using a four-point scale and postoperative pain using s visual analogue scale (VAS) ranging between 0 and 10.Results The three groups did not differ significantly regarding patient characteristics. The number of the patients shivering on arrival in the recovery room, and 10 and 20 minutes after operation were significantly less in Group P and K than in Group N. The time to first analgesic requirement in Group N was shorter than in either Group K or Group P (P0.05). There was no difference between the three groups regarding VAS pain score.Conclusion Prophylactic low-dose of ketamine is effective in preventing postoperative shivering.