Effect of Warm Bupivacaine on the Sensory Onset of Epidural Anaesthesia in Lower Limb Orthopaedic Surgery: A Double-Blind Randomized Clinical Trial

PURPOSE OF THE STUDY In this study we evaluated the effect of warm bupivacaine on the onset time of sensory block in patients undergoing lower limb surgery with epidural anaesthesia METHODS After approval by the Ethics Committee and written informed consents, 60 ASA physical status I and II patients, aged 18 to 75 years, undergoing elective lower limb surgery were studied in this randomized double-blind clinical trial. The patients having spinal anesthesia were divided into two groups. Group 1 received warm bupivacaine and group 2 was given bupivacaine at room temperature. The onset time and the level of sensory block were evaluated by a blind observer. Side effects (nausea, vomiting, shivering, headache, low back pain) were evaluated during surgery and in the post-operative period. RESULTS One patient was excluded from the study because of incomplete block; therefore 59 patients in two groups (29 patients in group 1 and 30 patients in group 2) were compared. The groups were matched on gender, age, weight and BMI. The onset time of sensory block at the levels of T12, L3 and L4 in group 1 was significantly shorter than in group 2 (p < 0.001). The difference in the onset time of sensory block at the upper levels of the spine between the two groups was not significant (p = 0.21). The incidence of side effects did not differ significantly (p = 0.18) between the two groups. CONCLUSIONS Warming bupivacaine can decrease the onset time of sensory block in epidural anaesthesia without any side effects in patients undergoing lower limb orthopaedic surgery.