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.

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 (MgSO4) and 0.5% isobaric levobupivacaine with 75-mg MgSO4 on the duration of analgesia in parturients undergoing elective caesarean section. 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 MgSO4 or 2 ml of 0.5% hyperbaric bupivacaine with 75-mg MgSO4 intrathecally. The duration of postoperative analgesia along with sensory and motor block characteristics and hemodynamics were studied. 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. Intrathecal levobupivacaine with MgSO4 produces a similar duration of postoperative analgesia as compared to hyperbaric bupivacaine with MgSO4. Early motor recovery allowing early ambulation postoperatively makes isobaric levobupivacaine with MgSO4 a good alternative for caesarean sections.