Postoperative analgesic effect of intrathecal dexmedetomidine on bupivacaine subarachnoid block for open reduction and internal fixation of femoral fractures.

Abstract

One of the drawbacks of subarachnoid block is the short duration of analgesia particularly when adjuvants are not added to local anesthetics agent used. However, dexmedetomidine an α2-adrenergic agent has been found to possess analgesic effect. This study seeks to determine the analgesic efficacy of intrathecal 7.5 μg of dexmedetomidine and its side effects when used for open reduction and internal fixation (ORIF) of femoral fractures. It is a prospective randomized, double-blinded study that was carried out in a Nnamdi Azikiwe University Teaching Hospital, Nnewi in Nigeria. Seventy American Society of Anesthesiologists I or II patients were randomized into two groups of 35 each to receive 3 ml of 0.5% hyperbaric bupivacaine combined with either 7.5 μg of dexmedetomidine in 0.3 ml of normal saline (Group D) or 0.3 ml of normal saline alone (Group S). Patient's outcome measures noted (time to first request of analgesia, proportion of patients with pain score <4 postoperatively using numerical rating scale [NRS], and total analgesic consumed in 24 h.). The patients in Group D had a longer time to first request of analgesia, larger proportion of patients with pain score <4 using NRS in the 2nd h postoperatively and lower amount of total analgesic consumed compared to those in Group S. These differences between the two groups were all statistically significant. Furthermore, there was no difference in the incidences of side effects between the two groups (P > 0.05). However, the patient satisfaction was better in Group D. The addition of 7.5 μg of dexmedetomidine to bupivacaine for subarachnoid block in the management of femoral fractures using ORIF provided better anesthetic profile, particularly prolonged duration of postoperative analgesia without significant side effects.