A randomized double-blind comparison of low-dose and high-dose bupivacaine for caesarean section in severely preeclamptic women using invasive blood pressure monitoring

Abstract

Background: The effect of a low dose of spinal local anesthetic on the incidence of hypotension has not been evaluated till date in severely preeclamptic women undergoing cesarean delivery. In this study, we compared the mean arterial pressure changes associated with low and conventional doses of spinal anesthetic in these women using invasive pressure monitoring. Materials and Methods: Twenty four severely preeclamptic women scheduled for elective cesarean delivery were randomly allocated to receive 7.5 mg [Group 1] or 10 mg [Group 2] of bupivacaine with 20 μg of fentanyl for spinal anesthesia. Heart rate and mean arterial pressure (MAP) were measured continuously using invasive arterial pressure monitoring. Phenylephrine boluses were used to maintain the MAP of >80% of baseline. The incidence of hypotension was compared between the two groups. Neonatal outcome was assessed using Apgar scores, umbilical cord blood gases, and need for resuscitation. Results: Incidence of hypotension was less in Group 1 as compared to Group 2 (41.6% vs. 91.6%, P = 0.009). Duration of hypotension was significantly longer in Group 2 compared to Group 1 (P = 0.005). Hypotensive episodes requiring vasopressors were more frequent in Group 2 (1.5 [1-3] vs. 0 [0-1]), P = 0.01) [Table 2]. There was no difference in Apgar scores, umbilical cord blood gases, and need for resuscitation between the two groups. Conclusion: Low dose of spinal bupivacaine resulted in a lower incidence of hypotension, higher predelivery MAP and decreased use of vasopressors in severely pre-eclamptic women undergoing cesarean section.