Abstract
OBJECTIVE: To evaluate the effect of preoperative intake of oral carbohydrates versus standard preoperative fasting prior to elective cesarean delivery on plasma purine levels (hypoxanthine, xanthine, and uric acid) and beta-hydroxybutyrate (β-HB) in mother's blood plasma and umbilical cord blood plasma. METHODS: Prospective randomized clinical trial, performed according to the Declaration of Helsinki, IRB approval (KB-0012/113/19, 13.05.2019). Patients with at term gestation with singleton uncomplicated pregnancies, scheduled for cesarean delivery under spinal anaesthesia were randomized in a 1:1 ratio to Group I (oral carbohydrate drinks (CHO Group, oral carbohydrate drink - 200 mL - 12.5% dextrose in water) 2 h prior to surgery in addition to standard solid fasting (6 h) or Group II which underwent only standard fasting (6 h - solids, 2 h for - liquids, SF Group). Blood samples were collected at 2 h after carbohydrate consumption (maternal) and at umbilical cord clamping (umbilical cord). The primary outcomes - plasma concentrations of hypoxanthine, xanthine, uric acid, in maternal blood and umbilical cord blood were measured using high-performance liquid chromatography. The secondary outcomes were blood pH, and lactate, and butyrate concentration. RESULTS: The study was conducted between August 2019, and March 2020 with 148 patients enrolled (75 CHO group; 73 SF group). Lower concentrations of hypoxanthine (3.87 (3.13-5.18) vs. 4.85 (3.88-6.53)µmol/l, p = 0.00050) and xanthine (0.79 (0.68-0.95) vs. 1.00 (0.88-1.22) µmol/l, < 0.00001) were observed in the maternal blood plasma and umbilical cord blood plasma (10.6 (8.00-16.5) vs. 13.9 (8.53-24.8) µmol/l, p = 0.035 and 1.05 (0.82-1.58) vs. 1.45 (0.94-3.17) µmol/l, p = 0.0035) in patients supplemented with carbohydrates. No difference in β-hydroxybutyrate concentration was noted. CONCLUSIONS: Oral carbohydrate loading prior to cesarean delivery was associated with lower plasma purine levels in maternal and umbilical cord blood. Further work to understand the role of the purinergic pathway and ATP metabolism in maternal and neonatal health may guide interventions such as carbohydrate loading to optimize outcomes. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04069806 (20190823).