Cardiac ultrasound-guided crystalloid preloading before spinal anesthesia vs. standard coloading for scheduled cesarean delivery: a randomized controlled trial.

BACKGROUNDS: Spinal anesthesia for cesarean delivery commonly causes maternal hypotension (60-80%), leading to adverse maternal and fetal outcomes. Standard crystalloid coloading is preferred over preloading, but individualized fluid strategies based on preload dependence remain untested.

METHODS

In this randomized controlled trial (NCT07108881) conducted at the Tunis Maternity Center, 96 ASA II women with singleton pregnancies scheduled for elective cesarean under spinal anesthesia and preload dependent (ΔLVOT VTI ≥ 12% after passive leg raising via cardiac ultrasound) were enrolled (n=96) and randomized to one of two groups. The active group (A, n=48) received titrated crystalloid preloading (250 mL increments guided by serial LVOT VTI until < 12%) plus standard coloading (10 mL/kg) and the control group (C, n=48) received coloading alone. The primary outcome was the hypotension incidence (SBP decrease > 20% baseline). Secondary outcomes were hypotension duration, rescue fluids, ephedrine use, nausea/vomiting, Apgar scores, and umbilical pH.

RESULTS

Groups were comparable at baseline. Hypotension incidence was lower in group A vs C (37.5% vs. 62.5%; P < 0.001; RR = 0.6, 95% CI 0.39-0.91). Hypotension duration was shorter (2.9 ± 1.4 vs. 5.2 ± 1.6 min; P = 0.012), lowest SBP higher (88 ± 7 vs. 82 ± 9 mmHg; P < 0.001), rescue crystalloids reduced (365 ± 130 vs. 482 ± 116 mL; P = 0.04), and nausea/vomiting lower (21% vs. 53%; P = 0.01). Ephedrine use and cardiac output were similar; umbilical pH was better in group A (7.34 ± 0.06 vs. 7.28 ± 0.06; P = 0.02).

CONCLUSION

Ultrasound-guided preload correction plus coloading reduces hypotension incidence, duration, rescue fluids, and maternal side effects in preload-dependent patients. Multicenter trials should validate integration into obstetric point of care ultrasounds protocols.