Effect of addition of intrathecal magnesium sulphate to 0.5% hyperbaric bupivacaine and 0.5% isobaric levobupivacaine on duration of analgesia in parturients undergoing elective caesarean section: A prospective randomised study

BACKGROUND AND AIMS: Addition of magnesium sulfate to local anesthetics improves the quality of spinal anesthesia for caesarean section. The aim of this study was to compare the effects of intrathecal 0.5% hyperbaric bupivacaine with 75-mg magnesium sulfate (MgSO(4)) and 0.5% isobaric levobupivacaine with 75-mg MgSO(4) on the duration of analgesia in parturients undergoing elective caesarean section. MATERIAL AND METHODS: This prospective randomized double-blind parallel-group study was conducted in 60 parturients undergoing elective caesarean section who were randomly allocated to Group I or Group II to receive either 2 ml of 0.5% levobupivacaine with 75-mg MgSO(4) or 2 ml of 0.5% hyperbaric bupivacaine with 75-mg MgSO(4) intrathecally. The duration of postoperative analgesia along with sensory and motor block characteristics and hemodynamics were studied. RESULTS: The duration of analgesia did not show a significant difference in the two groups (P = 0.175). The sensory onset time was faster in Group I (3.5 ± 1.3 min) as compared to that in Group II (4.8 ± 2 min; P = 0.004). The onset of motor blockade was not different in the two groups (P = 0.265), but there was a significant delay (P = 0.002) in motor recovery in Group II (267 ± 130.6 min) as compared to Group I (225 ± 85.4 min). Hemodynamics were comparable in the two groups. CONCLUSION: Intrathecal levobupivacaine with MgSO(4) produces a similar duration of postoperative analgesia as compared to hyperbaric bupivacaine with MgSO(4). Early motor recovery allowing early ambulation postoperatively makes isobaric levobupivacaine with MgSO(4) a good alternative for caesarean sections.