COMPARISON OF SPINAL BLOCK CHARACTERISTICS BETWEEN HEIGHT AND WEIGHT-BASED DOSAGE VERSUS FIXED DOSAGE OF INTRATHECAL ROPIVACAINE FOR ELECTIVE CESAREAN SECTION

Abstract

Background: Spinal anesthesia is commonly preferred for cesarean sections due to physiological changes in pregnancy, yet hypotension remains a challenge. This study aims to compare the efficacy of height and weight-adjusted doses of spinal ropivacaine with fentanyl versus a fixed dosage in elective cesarean sections.

Methods: A prospective, randomized, double-blind trial included 56 parturients undergoing elective cesarean sections under spinal anesthesia. Group A received height and weight-adjusted doses, and Group B received a fixed dose of hyperbaric ropivacaine with fentanyl. Baseline characteristics, sensory blockade levels, blockade achievement times, motor block duration, and hemodynamic parameters were recorded.

Results: While sensory blockade levels were similar between the two groups, Group B (fixed dose group) demonstrated significantly shorter times for achieving T6 (p = 0.007) and T4 (p = 0.034) levels. The group B had a higher fall in systolic blood pressure immediately after spinal (p=) and at 5 minutes (p=)  and in diastolic blood pressure immediately after spinal (p=) and at 15 minutes (p=). However, the total vasopressor (ephedrine) usage was similar between both groups. The heart rate was statistically lower in the fixed dose group immediately post-spinal (p=0.0005) and 15 mins (p=0.0005). But none of the patients in either groups required atropine. Both groups reported 100% adequacy in block and intraoperative analgesia.

Conclusion: While the fixed dose has the advantage of providing a significantly faster onset compared to dosing based on height and weight, the variable dosing group had more stable hemodynamics. Apart from this the highest sensory level, the duration of sensory and motor blockade, the quality of block as assessed by surgeon and patient’s satisfaction were similar between the groups.