INTRATHECAL HYPOBARIC VERSUS HYPERBARIC BUPIVACAINE WITH MORPHINE FORCESAREAN-SECTION

Both hyper- and hypobaric solutions of bupivacaine are often combined with morphine to provide subarachnoid anesthesia for cesarean section. Differences in the baricity of subarachnoid solutions influence the i ntrathecal distribution of anesthetic drugs and would be expected to i nfluence measurable clinical variables. We compared the effects of hyp er- and hypobaric subarachnoid bupivacaine with morphine to determine whether one has significant advantages with regard to intraoperative a nesthesia and postoperative analgesia in term parturients undergoing e lective cesarean section. Thirty parturients were randomized to receiv e either hyper- or hypobaric bupivacaine (15 mg) with morphine sulfate (0.2 mg). Intraoperative outcomes compared included extent of sensory block, quality of anesthesia, and side effects. Postoperative outcome s, including pain visual analog scale scores, systemic analgesic requi rements, and side effects, were monitored for 48 h. Sedation effects w ere quantified and compared using Trieger and digit-symbol substitutio n tests. We detected no differences in sensory or motor block, quality of anesthesia, quality of postoperative analgesia, incidence of side effects, or psychometric scores. Both preparations provide highly sati sfactory anesthesia for cesarean section and effective postoperative a nalgesia. Implications: Dextrose alters the density of intrathecal bup ivacaine solutions and is thought to influence subarachnoid distributi on of the drug. We randomized parturients undergoing cesarean section to one of two often used spinal bupivacaine preparations, hypobaric an d hyperbaric. We detected no differences in clinical outcomes between groups.