The Efficacy of Epidural Ketamine on Shivering during Transurethral Resection of the Prostate under Epidural Anesthesia

Abstract

Ketamine may decrease core-to-peripheral redistribution of heat through direct central sympathetic stimulation and inhibition of norepinephrine uptake into postganglionic sympathetic nerve endings. The purpose of this study was to evaluate the efficacy of epidural ketamine in preventing shivering during transurethral resection of the prostate (TURP) under epidural anesthesia. Ninety-three male patients scheduled for TURP under epidural anesthesia were enrolled in this study. Patients were randomized into one of three groups. Group 1 consisted of 31 patients who received epidural 0.75% ropivacaine, group 2 consisted of 32 patients who received epidural ketamine (0.2 mg/kg) in addition to 0.75% ropivacaine, and group 3 consisted of 30 patients who received epidural ketamine (0.4 mg/kg) in addition to 0.75% ropivacaine. Shivering and side effects such as hypotension, bradycardia, nausea, and hallucination were recorded during the anesthesia and for 2 hours while in the postanesthetic recovery room. Shivering was statistically more frequent in group 1 than in the other groups. The incidence of sedation was significantly higher in group 3 than in the other groups. The incidences of side effects such as hypotension, bradycardia, and nausea were significantly higher in group 1 than in the other groups. In this study, epidural ketamine 0.2 mg/kg and 0.4 mg/kg was shown to have a lower incidence of shivering and other side effects except sedation. In patients who undergo TURP under epidural anesthesia, the prophylactic use of low-dose epidural ketamine would be helpful in preventing any adverse effects, including shivering.