A Comparison of Intravenous Dexamethasone, Pethidine and Ketamine in the Prevention of Postoperative Shivering in Patients Undergoing General Anesthesia

Introduction and Purpouse: Postoperative shivering, which is unpleasant and annoying to the patient, occurs in patients with general anesthesia occurring in up to 65% of cases. Different mechanisms have been proposed for postoperative shivering. Chills after anesthesia can cause cardiovascular complications, bleeding and infections. this study, effects of dexamethasone, pethidine and ketamine have been compared in prevention shivering after general anesthesia. Materials and Methods: In this double-blind randomized study with placebo group, 164 patients with ASA class one and two aged between 20-60 years old who were under general anesthesia were selected. The patients were equally divided into 4 groups of 41 each. After induction of anesthesia and before surgery, in the first group, 0.15 mg / kg dexamethasone, the second group 0.5 mg / kg of ketamine, the third group 0.5 mg of pethidine and the four  group received normal saline 0.9% with 2 cc volume in all groups. Upon completion of surgery, the patients were controlled regarding the observable shivering by the researcher. The data were analyzed using SPSS software Version 19. Results: The results showed that the frequency and intensity of occurrence of shivering in dexamethasone group (p = 0.009), in pethidine group (p = 0.004), and in ketamine group (p = 0.000) were less than those of control groups. That is, there was a significant difference among the dexamethasone, pethidine, and ketamine groups and their corresponding control groups. Further, there was no significant difference between the dexamethasone and pethidine groups regarding the frequency and intensity of occurrence of shivering (p = 0.565). Similarly, no significant difference was observed between the dexamethasone and ketamine groups with regard to the frequency and intensity of occurrence of shivering (p = 0.071). Moreover, the frequency and intensity of occurrence of shivering between the pethidine and ketamine groups was not significantly different (0.063). Conclusion :The results indicated that dexamethasone, pethidine, and ketamine are effective in preventing the occurrence of shivering. Also, there is no difference among these three medicines in prevention of postoperative shivering.