Abstract
Background: Prolongation of spinal analgesia extends not only the duration of surgical anaesthesia but also provides postoperative analgesia. The effects of adjuvants like dexmedetomidine and magnesium sulphate to intrathecal bupivacaine are compared in this study.
Materials and Methods: In a prospective randomized double-blinded placebo-controlled study, 90 adult patients of American Society of Anaesthesiologists (ASA) physical status I and II scheduled for lower abdominal and lower limb surgeries were randomly allocated to one of three groups: Group-D (n=30) received 12.5mg(2.5ml) hyperbaric bupivacaine 0.5% plus 10µg (0.1ml) dexmedetomidine, Group-M(n=30) received 12.5mg(2.5ml) hyperbaric bupivacaine plus 50mg (0.1ml) magnesium sulphate 50%, and Group-C (n=30) received 12.5mg (2.5ml) hyperbaric bupivacaine plus 0.1ml normal saline 0.9% without preservative intrathecally. The onset times to reach T10 sensory and Bromage 3 motor block, peak sensory block level, time to reach peak block, time to two segment regression, the regression times to reach S1 sensory level and modified Bromage 0 motor scale, side-effects, and time to first analgesic request after surgery were assessed.
Results: The onset time of sensory and motor blockade were significantly shortened in group D (2.53±0.57 min.) and prolonged in group M (8.00±1.29 min.) compared to group C (4.10±0.55 min.).Dexmedetomidine group showed significantly prolonged time to two segment regression (group D vs group M -132.33 ±12.51 min. vs. 91.83 ±9.69 min.; p

Key words: spinal anesthesia, adjuvant, dexmedetomidine, magnesium sulphate, analgesia