Supplemental oxygen during cesarean deliveries under neuraxial anesthesia and fetal outcomes: A meta-analysis
Abstract Number: 43
Abstract Type: Meta Analysis/Review of the Literature
Introduction: Controversy exists as to whether supplemental oxygen is necessary during cesarean deliveries under neuraxial anesthesia.1,2 We conducted a meta-analysis to further investigate this issue.
Methods: A systematic search of the published literature was performed to identify randomized controlled trials (RCTs) published in any language that randomized parturients undergoing cesarean delivery under neuraxial anesthesia to air or oxygen and compared fetal outcomes (1- and 5- min Apgar scores, uterine arterial and venous cord gases). Pubmed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched using the following subject headings: supplemental oxygen, maternal, cesarean delivery, fetal status, and fetal outcomes. Inclusion criteria included: only cesarean deliveries under neuraxial anesthesia which were published in peer-reviewed journals. Relevant data were abstracted from accepted articles. Standardized mean differences were determined for each of the outcome measures that were reported in at least two trials using a random-effects model. The meta-analysis was performed using Comprehensive Meta-Analysis 2 software (Biostat Inc., Englewood, NJ). All tests were two-tailed and a P <0.05 was considered significant.
Results: A total of 9 studies met the inclusion criteria. There were no differences in the 1- or 5- min Apgar scores, UV pH, UV BE, UA pH, UA pCO2, or UA BE (P>0.05 for each). There was an increase in the UV pCO2, UV pO2 (Figure), and UA pO2 levels in the oxygen compared to the air group (P= 0.04, <0.001, and 0.03 respectively).
Discussion: Our results indicate that there may be a benefit to supplemental oxygen administration as there was a modest increase in the uterine venous and arterial partial pressure of oxygen. While there was no difference in Apgar scores, this is a gross measure of fetal well-being, and may not detect subtle differences in biochemical status. Further study with more long-term outcomes is warranted.
References: 1. Backe SK et al. (2007) EJA 24:66-70. 2. Khaw KS et al. (2002) BJA 88: 18-23.