Height Adjusted Dose versus Height-Weight Adjusted Dose of Intrathecal Hyperbaric Bupivacaine for Caesarean Delivery for Preventing Maternal Hypotension: A Prospective, Double-Blinded, Randomized Controlled Study

Abstract

Background: Spinal anesthesia for cesarean section is associated with significant hypotension due to sympathetic blockade and can cause adverse maternal and fetal outcomes. Although hypotension is considered to be dose-dependent, choosing a dose of bupivacaine to achieve an adequate level of blockade without causing hypotension is a challenge. Methods: Ninety-six eligible parturients posted for elective cesarean section under spinal anesthesia were divided into two groups. Group H received intrathecal bupivacaine dose calculated as per patients’ height and Group HW received intrathecal bupivacaine dose calculated as per patients’ height and weight chart. Heart rate and mean blood pressure were monitored in both groups. Time required to achieve sensory block up to T6, complete motor block, the dose of ephedrine required to treat hypotension, the incidence of complications, and neonatal appearance, pulse, grimace, activity, respiration (APGAR) scores were noted. Results: Hypotension occurred in 35.56% of parturients in Group H and 16.28% of parturients in Group HW, which was statistically significant. The mean dose of 0.5% bupivacaine was 9.12 mg in Group HW and 9.4 mg in Group H (P value = 0.02). The mean dose of Ephedrine was 12 ± 5.8 mg in Group H compared to 6.0 mg in Group HW, which was statistically significant. The time needed to achieve sensory and complete motor block were comparable in both groups. Conclusion: Height-weight-adjusted intrathecal hyperbaric bupivacaine achieved comparable sensory and motor block with lesser incidence and severity of hypotension compared to height-adjusted dose.