Fetal benefit of maternal oxygen supplementation during elective Cesarean section under neuraxial anesthesia: a systematic review
Abstract Number: 176
Abstract Type: Meta Analysis/Review of the Li
Introduction: Maternal oxygen supplementation during general anesthesia for Cesarean section has been shown to improve fetal oxygen delivery and neonatal outcomes.1 Its use for fetal benefit during elective Cesarean sections performed under neuraxial anesthesia remains controversial.2,3 In this systematic review we assess the evidence supporting the routine use of maternal supplemental oxygen, for fetal benefit, when a neuraxial technique is used during an elective lower segment Cesarean section delivery of an uncompromised fetus.
Methods: Multiple electronic databases were searched to identify candidate trials, which were included in the review if they were randomized controlled trials (RCTs) of healthy parturients undergoing elective Cesarean section using a neuraxial anesthetic technique, and were published in English. References were then hand searched for other appropriate trials. Two authors independently assessed each paper for inclusion and study quality. Independent data extraction was carried out by two reviewers.
Results: Nine RCTs were included, comprising 570 deliveries.(2,4-11) Methodologically, there was only one high quality study. The others were limited by inappropriate method of randomization, inadequate description of randomization and blinding, lack of blinding, deficiencies in follow up, and absence of allocation concealment. A range of fractional inspired oxygen concentrations (0.21-1.0) were used within the selected RCTs. All studies examined fetal oxygen delivery (as measured by umbilical venous pO2 (UVpO2)), and fetal clinical outcome (as measured by Apgar scores). Seven RCTs assessed umbilical artery pH (UApH). Five of the nine RCTs found a significant difference in UVpO2 when maternal oxygen supplementation was used compared to room air. There were no significant differences found in Apgar scores, UApH or UVpH values, or Neurologic Adaptive Capacity Scores between groups.
Discussion: This review suggests that a very high FiO2 (>60%) is required to produce an increase in fetal oxygenation, as measured by UVpO2. Biochemical and clinical markers of fetal outcome do not appear to improve with maternal oxygen supplementation when a neuraxial technique is used during an elective lower segment Cesarean section delivery of an uncompromised fetus, regardless of the FiO2 supplied.
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