A Randomized Evaluation of Prophylactic Phenylephrine and Left Uterine Displacement for the Reduction of Hypotension After Spinal Anesthesia in Cesarean Delivery

TL;DR

This study compared two methods to prevent low blood pressure during spinal anesthesia for cesarean sections but found no significant difference between them.

Contribution

The study provides new evidence comparing phenylephrine and left tilt for hypotension prevention during cesarean delivery.

Findings

Phenylephrine and left tilt had similar hypotension rates (65.3% vs 54.2%) with no statistical difference.

Higher BMI and lower baseline blood pressure were significant predictors of hypotension in both groups.

Neither method was significantly more effective, suggesting the need for combined or stronger interventions.

Abstract

Background

Spinal anesthesia-induced hypotension is a frequent and critical problem during cesarean section, carrying risks for both mother and fetus. Prophylactic vasopressors and mechanical manipulation of the uterus are common preventative methods. The primary aim of this study was to assess the effectiveness of prophylactic phenylephrine bolus versus 15° left lateral tilt in preventing maternal hypotension.

Material and methods

In this randomized comparative study, 144 women who were planned to undergo elective cesarean delivery under spinal anesthesia were divided into two groups. Group A (n=72) was given a prophylactic intravenous bolus of 100 mcg of phenylephrine immediately after spinal injection. In group B (n=72), patients were placed in a 15° left lateral tilt with an obstetric wedge. The only outcome was the occurrence of hypotension (systolic pressure 20% decrease from baseline).

Results

Hypotension occurred in 65.3% (n=47) of patients in the phenylephrine group and 54.2% (n=39) of patients in the left tilt group. The difference between these groups was not statistically significant (p=0.159). Patients with a BMI over 30 kg/m² showed a higher incidence of hypotension after spinal anesthesia. However, there was no statistically significant difference in hypotension rates between those receiving phenylephrine and those positioned in a 15° left lateral tilt within this subgroup. Similarly, low baseline systolic blood pressure (SBP; 100-120 mmHg) was also a significant predictor of hypotension in both groups.

Conclusion

There was no benefit of phenylephrine 100 mcg bolus over a 15° tilt in the prevention of spinal anesthesia-induced hypotension for elective cesarean delivery. Both methods are popular options, but they may not be enough as individual prophylactic measures, and this might indicate the necessity of combination or more aggressive therapy.