Prophylactic phenylephrine bolus versus infusion for prevention of maternal hypotension during spinal anaesthesia for caesarean section at Windhoek-based teaching hospitals, Namibia
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Date
2022
Authors
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Publisher
University of Namibia
Abstract
Background: Maternal hypotension is a common complication of spinal anaesthesia during caesarean delivery. Injection of vasopressors with non-pharmacological measures have been investigated for prevention of martenal hypotension as well as the foeto-maternal effects of treatment.
Aim: The primary aim of the study was to compare prophylactic 50 mcg phenylephrine bolus (PB) with a fixed continuous 25 mcg/min phenylephrine infusion (PI). The secondary aim was to assess the side effects and neonatal outcomes of the two treatments.
Settings and design: A prospective, randomised, controlled double-blinded study was conducted in the maternity theatres of Windhoek Central Hospital and Katutura Intermediate Hospital.
Methods and Materials: Ninety-two eligible parturients, ASA I and II, scheduled for elective caesarean section under spinal anaesthesia were recruited and randomised into two groups. PB group received a prophylactic 50 mcg phenylephrine (PE) bolus immediately after spinal anaesthesia whereas PI group received prophylactic 25 mcg/min PE infusion. Maternal blood pressure, heart rate and side effects were recorded every minute for the first 20 minutes while neonatal outcome was assessed with Apgar score at the 1st and 5th minute.
Statistical Analysis: Categorical variables were presented in numbers and percentages.
Normally distributed continuous variables were presented as mean standard deviation (±SD) and compared using t-test. Non normally distributed continuous variables were compared with Mann-Whitney test. A p-value of p< 0.05 was considered significant.
Results: Parturients in the PI group had a significantly lower incidence of hypotension than PB
group (32% vs 71% p = 0.0001). Nausea and vomiting was lower in PI group than PB group (13% vs 31% p = 0.033). Reflex bradycardia was comparable between groups (p= 0.489). No parturient in the PB group had reactive hypertension whereas 11% of participants in PI group did (p=0.024). Participants in the PI group received about 36% more phenylephrine than the PB group (p=0. 0277). Apgar scores between the two groups showed good neonatal outcomes.
Conclusion: There was better control of blood pressure in the PI group than PB group. Both groups had similar incidence of reflex bradycardia as well as good neonatal outcomes.
Intraoperative nausea and vomiting (IONV) was higher in the PB group than PI group, whereas no reactive hypertension experienced in PB group.
Description
A thesis submitted in partial fulfillment of the requirement for the Degree of Master of Medicine (Anaesthesiology, Critical Care and Pain Management)
Keywords
Spinal induced hypotension, Spinal anaesthesia, Prevention, Caesarean section