Adverse Outcomes Associated with Time from Neuraxial Anesthesia to Delivery among Non-Labor Cesarean.

OBJECTIVE

Prior studies showing an inverse association between time from spinal anesthesia to delivery and umbilical artery (UA) pH were relatively small cohorts or included only spinal anesthesia. In a large cohort of unlabored cesarean deliveries, we further investigated this association.

STUDY

DESIGN

This is a secondary analysis of a retrospective cohort study of singleton, term, non-anomalous pregnancies delivered by non-labor cesarean with neuraxial anesthesia, inclusive of spinal, epidural, or combined spinal-epidural. We assessed outcomes with time intervals from neuraxial placement to delivery: < 20, 20-39, 40-59, and ≥ 60 minutes. The primary outcome was UA pH < 7.1. We further analyzed the time intervals for surgical procedural steps among neonatal UA pH cohorts: ≤ 7.00, 7.01-7.10, 7.11-7.20, 7.21-7.30, and ≥ 7.31. Multivariable logistic regression adjusting for baseline confounders was used to determine the strength of association.

RESULTS

Of the 5,255 cesarean deliveries, 645 (12.3%) delivered within 20 minutes, 4,067 (77.4%) delivered between 20 and 39 minutes, 468 (8.9%) delivered between 40 and 59 minutes, and 75 (1.4%) delivered in ≥ 60 minutes from neuraxial anesthesia. Increased time from neuraxial placement to delivery was associated with UA pH < 7.1 and < 7.2, UA base deficit > 8, and meconium-stained amniotic fluid (all p < 0.05). After adjusting for confounders and using < 20 minutes as the reference, increased time from neuraxial placement to delivery was no longer associated with adverse outcomes. There was an inverse relationship with pH and time from neuraxial placement to delivery, skin incision to uterine incision, and uterine incision to delivery (all p < 0.01).

CONCLUSION

Our study suggests that although increased time from neuraxial anesthesia to delivery is associated with lower UA pH, these findings are significantly affected by clinical factors such as body mass index (BMI), hypertension, or diabetic disorders, type of neuraxial anesthesia, number of prior cesarean deliveries, and surgical factors such as duration of procedural steps.

KEY POINTS: · Our study is inclusive of spinal, epidural, and combined spinal-epidural anesthesia.. · Our findings reveal an association between time from neuraxial placement and low UA pH, which is confounded by numerous clinical factors.. · When assessing duration of each step, only increased duration of surgical steps is associated with lower UA pH and not presurgical preparation..