Moderate rate of implementation of spinal anesthesia for cesarean section: does it improve neonatal well-being? A case-control study.

Before 2013, almost none of the cesarean section (CS) deliveries at our institution were performed with spinal anesthesia (SA), but after 2013 SA became the first-choice anesthesia for CS because it achieved better neonatal outcomes. However, the current rate of SA implementation at our institution was estimated to be approx. 60-70%, which is intermediate between these at other institutions in Japan or in other countries. This raises a question: What rate of SA use among CS cases achieves the best neonatal outcomes? To answer this question, we conducted this single-center case-control study with 1326 CS cases between 1994 and 2017 and compared the neonatal outcomes before to those after 2013. The logistic regression models were prepared to estimate the risk of birth asphyxia defined as a 5-min Apgar of < 7, associated with eight potential confounders, including the modified anesthetic protocol. The modified protocol was not a significant independent factor for neonatal asphyxia, indicating that our moderate SA priority protocol did not improve the neonatal outcomes even when compared to the outcomes at a 0% SA rate. A > 70% rate of SA implementation may be needed to provide better neonatal outcomes.