ESRA19-0124 Slightly more time is necessary to achieve neuraxial anesthesia in obese patients for cesarean section. – A retrospective cohort study in a japanese tertial hospital-

Background and aims Neuraxial anesthesia is preferred to general anesthesia for cesarean section (CS), especially in obese patients. However, it is often technically challenging in these patients, and the uncertainty of the time needed to induce anesthesia is a potential problem. Therefore, in this retrospective study, we examined the relationship between obesity and the time taken to receive subarachnoid injection of local anesthetics after entering the operating room. Methods We reviewed electronic medical records of patients who had undergone CS under neuraxial anesthesia in our hospital between the start of 2010 and the end of June 2018. A total of 795 (49.0%) patients underwent spinal anesthesia while 722 (44.5%) underwent combined spinal-epidural (CSE) anesthesia. The effects of obesity, expressed as body mass index (BMI), on the anesthesia procedure time (AP-time) of neuraxial anesthesia were analyzed in the spinal and CSE anesthesia groups separately. Results The AP-time was longer in obese patients than in non-obese ones in both the spinal and CSE anesthesia groups. This effect was also confirmed, with a weak significant linear correlation, between AP-time and BMI, but the variations within each BMI class were considerably higher (95% confidence interval, 20 min). Conclusions This retrospective study using medical records from a single hospital showed that obesity in pregnancy marginally prolongs the time needed to achieve neuraxial anesthesia. The effect was, however, less than the variation within the same BMI class.