# Comparison of supine vs head-elevated position on sensory block height following combined spinal epidural anaesthesia in Class III obese parturients undergoing elective caesarean delivery- a randomized controlled trial

## TL;DR

This study compares two positions during spinal anesthesia for obese pregnant women and finds that head elevation lowers the spread of anesthesia without affecting its effectiveness.

## Contribution

The study provides new evidence on the impact of positioning on sensory block height in class III obese parturients.

## Key findings

- The HELP position significantly reduced the sensory block level compared to the standard position.
- Block adequacy and clinical outcomes were similar between the two groups.
- Ramped positioning supports airway access without compromising anesthesia efficacy.

## Abstract

Neuraxial anaesthesia is the preferred technique for caesarean delivery due to its superior safety profile and maternal–foetal benefits. However, general anaesthesia may still be required in emergencies or failed neuraxial attempts, particularly in obese parturients. Optimal airway management in this group is critical and the ramped position has been shown to improve preoxygenation, airway patency, and intubation conditions. While the ramped position may reduce the cephalad spread of local anaesthetic in non-obese patients, its effect in class III obese parturients remains unclear.

This single-centre, prospective, randomized controlled trial was conducted between May 2023 and July 2024 at the Women’s Wellness and Research Centre, Doha, Qatar. Ninety class III obese parturients (Body mass index ≥ 40 kg/m2) scheduled for elective caesarean delivery under neuraxial anaesthesia were randomized to either the Standard Pillow (SP) group or the Head Elevated Laryngoscopy Position (HELP) group. All participants received combined spinal-epidural anaesthesia. The primary outcome was sensory block level, assessed 15 min after intrathecal injection using cold and pinprick tests. Secondary outcomes included block adequacy, epidural supplementation, analgesic requirements, incidence of maternal hypotension, vasopressor requirements, maternal satisfaction and neonatal outcomes.

Of 2,740 women screened for eligibility, 90 were randomized, with 82 included in the final analysis. HELP group: n = 39; SP group: n = 43. Baseline characteristics were comparable between groups. At 15 min post-intrathecal injection, the HELP group demonstrated a significantly lower median sensory block level (T4) compared to the SP group (T2) for both cold and pinprick sensation (p < 0.001). There were no significant differences between groups in terms of block inadequacy, opioid or epidural supplementation or conversion to general anaesthesia.

Ramped positioning resulted in a lower sensory block height following spinal anaesthesia in class III obese parturients compared to standard positioning. Despite the reduced cephalad spread, block adequacy and clinical outcomes remained comparable, supporting the use of the HELP position to optimize airway access without compromising anaesthetic efficacy.

The trial was retrospectively registered at ClinicalTrials.gov under NCT06889337 on 23rd; Feb, 2025.