Preoperative free access to water compared to fasting for planned cesarean under spinal anesthesia: a randomized controlled trial

BACKGROUND Contemporary guidance for preoperative feeding allows solids up to six hours and clear fluid up to two hours before anesthesia. Clinical trial evidence to support this approach for cesarean section is lacking. Many medical practitioners continue to follow conservative policies of no intake from midnight to the time of surgery, especially in pregnant women. OBJECTIVE To evaluate the pragmatic approach of permitting free access to water to the point when the operating theater call to dispatch the woman compared to fasting from midnight in preoperative oral intake restriction for planned cesarean under spinal anesthesia on perioperative vomiting and maternal satisfaction. STUDY DESIGN A randomized controlled trial was conducted in the Obstetric Unit, Universiti Malaya Medical Center from October 2020 to May 2022. 504 participants scheduled for planned cesarean delivery were randomized: 252 each to preoperative free water access until the call to dispatch to the operating theater or fasting from midnight. The primary outcomes were perioperative vomiting and maternal satisfaction. Analyses were performed using t-test, Mann-Whitney U and Chi-Square test as appropriate. RESULTS Vomiting at up to six hours after completion of cesarean delivery were 9/252 (3.6%) vs. 24/252 (9.5%) RR 0.38 95% CI 0.18-0.79 p=0.007 and maternal satisfaction score (0-10 VNRS) median [interquartile range] 9 [8-10] vs. 5 [3-7] p<0.001 for preoperative free access to water and fasting respectively. Assessed before dispatch to the operating theater, thirst was reported by 69/252 (27.4%) vs. 134/252 (53.2%) RR 0.52 95% 0.41-0.65 p<0.001, capillary glucose level (mmol/l) mean ± standard deviation 4.8 ± 0.7 vs. 4.9 ± 0.8 p=0.048, and preoperative intravenous fluid hydration commenced in 49/252 (19.4%) vs. 76/252 (30.2%) RR 0.65 95% 0.47-0.88 p=0.005 for free access to water and fasting respectively. In the operating theater, ketone was detected in the catheterized urine in 38/252 (15.1%) vs. 78/252 (31.0%) RR 0.49 (5% CI 0.25-0.59 p<0.001 and the number of doses of vasopressors needed to correct hypotension were 2.3 ± 1.7 vs. 2.7 ± 2.2 p=0.009 for free access to water and fasting respectively. Recommendation of allocated preoperative oral intake regimen rates to a friend were 240/252 (95.2%) vs. 100/252 (39.7%) RR 2.40 95% CI 2.06-2.80 p<0.001 in favor of free access to water. Other assessed maternal and neonatal outcomes were not different. CONCLUSION Free access to water compared to fasting in planned cesarean delivery reduced perioperative vomiting and was strongly favored by women. A number of pre and intraoperative secondary outcomes were also improved. However, post cesarean recovery and neonatal outcomes were not different.