Prophylactic granisetron vs pethidine for the prevention of postoperative shivering: a randomized control trial

Shivering-the "Big Little Problem" has an incidence of 60% in early recovery phase following general anaesthesia. A number of techniques have been tried to prevent postoperative shivering. Previous study showed that, ondansetron in higher doses reduces postoperative shivering. Therefore, this study was done to compare the efficacy of prophylactic granisetron, pethidine and placebo in preventing postoperative shivering. Ninety patients aged 20-60yrs, ASA physical status I and II, scheduled for laparoscopic surgery under general anaesthesia were randomly allocated to receive either normal saline (Group S, n=30) as negative control, pethidine 25mg (Group P, n=30) as positive control or granisetron 40mcg.kg(-1) (Group G, n=30) intravenously before induction. The anaesthesia was induced with fentanyl 2mcg.kg(-1), propofol 2mg.kg(-1) and atracurium 0.5mg.kg(-1) and maintained with sevoflurane 1 - 1.5%. Nasopharyngeal temperature was measured throughout the procedure. An investigator, blinded to the treatment group, graded postoperative shivering in a scale of 0 to 4. (0= no shivering, 1= piloerection or peripheral vasoconstriction but no visible shivering, 2= muscle activity in only one muscle group 3= muscle activity in more than one muscle group, 4= shivering involving the whole body). Prophylaxis was regarded as ineffective if shivering was greater than grade 3 and intravenous pethidine 25 mg was administered as rescue medication. The three groups did not differ significantly regarding patient characteristics. The numbers of patients shivering on arrival in the recovery room at 15 minutes after operation were significantly less in Group P (7%) and Group G (17%) than in Group S (60%). Groups P and G differ significantly than in Group S (p<0.05). However, the difference between Groups P and G was not statistically significant (p>0.05). The prophylactic use of granisetron (40mcg.kg(-1)) and pethidine(25mg) intravenous were found to be effective in preventing postoperative shivering.