Intrathecal Meperidine versus intrathecal Fentanyl for prevention of shivering in lower limb orthopedic surgeries under spinal anesthesia: A randomized double-blind placebo-controlled trial

Shivering is an unpleasant sensation for patients who undergoing spinal anesthesia. This randomized double-blind clinical trial study was designed to compare the effect of intrathecal fentanyl with intrathecal meperidine for prevention of shivering in lower limb orthopedic surgeries under spinal anesthesia. Ninety patients were randomly recruited to receive either 3 ml of 0.5% hyperbaric bupivacaine plus 20 μg of fentanyl (Group F), or 3 ml of 0.5% hyperbaric bupivacaine plus 0.2 mg/kg of meperidine (Group M), or 3 ml of 0.5% hyperbaric bupivacaine plus normal saline (Group S). The incidence and intensity of shivering were compared in three groups. Data were analyzed by analysis of variances, Mann-Whitney U-test followed by Chi-square test. There were not statistically differences in complications and side-effects between three groups. Total incidence of shivering was similar between Groups F and M (16.7% vs. 13.3% respectively, P = 0.72) whereas it was significantly different to Group S (43.3%) (P = 0.025 for Group F vs. S, and P = 0.011 for Group M vs. S). Also the intensity of shivering between Groups F and M was similar (P = 0.66), while it was significantly less in these groups compared to Group S (P = 0.013 and P = 0.004, respectively). Addition of fentanyl 20 μg or meperidine 0.2 mg/kg to 0.5% bupivacaine intrathecally significantly decreased the incidence of shivering in lower limb orthopedic surgeries. There was no significant difference between two drugs with this respect.