Effect of combined colloid preloading and crystalloid coloading versus combined colloid and crystalloid coloading on maternal cardiac output during spinal anesthesia for cesarean section under combined prophylactic noradrenaline infusion.

Objective: Hypotension is a common complication of spinal anesthesia during cesarean section, and no single intervention has been shown to eliminate maternal hypotension. Fluid loading strategies combined with vasopressor drug regimens can achieve this goal by maximizing cardiac output (CO) and minimizing the fall in systemic vascular resistance (SVR). However, the optimal fluid volume, type, and timing of administration have not been fully elucidated. Therefore, this study aimed to use Vigileo techniques in order to compare the effects of different fluid loading strategies on CO fluctuation under a norepinephrine infusion. Methods: We recruited 102 healthy term parturients scheduled for elective cesarean section under spinal anesthesia for this randomized double-blind study and divided them into two groups: the colloid preload followed by crystalloid coload group (500 ml each; Group 1, Results: Baseline CO, SV, and SBP were similar for both groups. Before spinal anesthesia, CO (6.84 ± 1.18 vs. 5.51 ± 0.96 L/min, Conclusion: In combination with prophylactic norepinephrine infusion, 500-mL colloid preloading and 500-mL crystalloid coloading can significantly increase CO before spinal anesthesia for cesarean sections and provide improved hemodynamic stability after spinal anesthesia, with no difference in maternal or neonatal outcomes as compared to colloid and crystalloid coloading. Clinical trial registration: https://www.chictr.org.cn, identifier ChiCTR2300073333.