THE EFFICACY OF THREE DIFFERENT DOSES OF INTRATHECAL FENTANYL FOR PREVENTION OF SHIVERING IN LOWER LIMB ORTHOPEDIC SURGERIES: A RANDOMIZED DOUBLE-BLIND CONTROLLED TRIAL

Background: Fentanyl has been used to prevent shivering in spinal anesthesia but still the effects of different doses have not been appropriately specified. The aim of this study was to assess the effect of 10 μg, 20 μg and 30 μg intrathecal fentanyl on prevention of shivering during and after lower limb orthopedic surgeries under spinal anesthesia. Materials and Methods: One hundred and twenty patients undergoing elective orthopedic surgery under spinal anesthesia were enrolled in this clinical trial. Subjects were randomly divided to four groups; Group P received 3 cc bupivacaine 0.5% plus normal saline intrathecally; Group A10 received 10 μg fentanyl plus 3 cc bupivacaine 0.5% intrathecally; Group B20 received 20 μg fentanyl plus 3 cc bupivacaine 0.5% intrathecally; and Group C30 received 30 μg fentanyl plus 3 cc bupivacaine 0.5% intrathecally. Shivering and the complications were recorded. Results: Shivering intensity was different between 4 groups (P = 0.014). There was no moderate, severe and very severe shivering seen in Group C30 but there was 16.7% moderate, 10% sever, and 6.7% very severe shivering seen in Group P. The total incidence of shivering after spinal anesthesia in Groups A10, Group B20, Group C30 and Group P were 53.5%, 26.7% , 6.7% and 63.3% respectively and there was statistically significant difference between 4 group in this regard (P < 0.001). Conclusion: Intrathecal bupivacaine combined with 30 μg fentanyl was superior to using 10 μg or 20 μg fentanyl for prevention of shivering during lower extremity orthopedic surgery.