Background: This study is a network meta-analysis to compare maternal and fetal outcomes associated with four different anesthetic techniques for cesarean delivery. Methods: An arm-based, random-effects frequentist network meta-analysis was performed. A random effect model was selected considering deviance information criteria. Randomized trials reporting the following outcomes were included: Apgar score at 1-or 5-min; umbilical arterial and venous pH; umbilical arterial pH <7.2; and neonatal score at 2-4 hours. Loop-specific heterogeneity was evaluated by risk of odds ratio and s 2. Quality of evidence was assessed using the GRADE approach. Results: Data from 46 randomized trials including 3689 women contributed to the study. There were significant differences in Apgar score 6 at 1 min between spinal versus general anesthesia (odds ratio 0.27, 95% confidence interval [CI] 0.13 to 0.55: moderate quality evidence) and Apgar scores at 1-and 5-min, favoring spinal anesthesia. Umbilical venous pH associated with epidural anesthesia was significantly higher than that with general anesthesia (mean difference 0.010, 95% CI 0.001 to 0.020: moderate quality evidence) or spinal anesthesia. Spinal anesthesia was ranked best for Apgar score 6 at 1-min (SUCRA=89.8), Apgar score at 1-min (SUCRA=80.4) and 5-min (SUCRA=90.5). Epidural anesthesia was ranked highest for umbilical venous pH (SUCRA=87.4) and neonatal score (SUCRA=79.3). Conclusions: Spinal and epidural anesthesia were ranked high regarding Apgar scores and epidural anesthesia was ranked high regarding umbilical venous pH, but the results were based on small heterogeneous studies with high or unclear risks of bias.

Decreased oxygenation by pneumoperitoneum was improved and PaCO did not increase after 1 h of I:E of 1:1; however, the effect of equal ratio ventilation longer than 1 h remains to be determined. There was no carryover effect of the two different I:E ratios.

preferences suggest that the highest FiO 2 group (Group 5) was not a comparable group to the others, and possibly they were much sicker. The link between hyperoxia and potential harms in tissue-under-threat is mechanistically well established, but this is not necessarily true for high FiO 2 use. 10 Therefore, I believe the implication of high intraoperative FiO 2 use as a cause is currently unjustifiable.

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