Comparative Analysis of the Predictive Performance of Noninvasive Beat-by-Beat Blood Pressure and Flow Measurements at the Lower Extremity Versus the Upper Extremity for Neonatal Outcomes Under Spinal Anesthesia for Elective Cesarean Delivery

Enrolled parturients undergoing elective cesarean delivery under spinal anesthesia will participate in this prospective, observational study following informed consent. Standard perioperative care will be maintained, including administration of spinal anesthesia (1.6 mL of 0.75% hyperbaric bupivacaine with fentanyl 10 mcg and morphine 100 mcg), crystalloid co-loading, and a prophylactic phenylephrine infusion. For study purposes, the ClearSight™ system will be applied noninvasively to both the upper and lower extremities, with a finger cuff placed on the ring finger of the arm opposite the intravenous line and a toe cuff placed on the left foot, while a standard oscillometric blood pressure cuff will be placed on the same arm. Continuous beat-by-beat blood pressure and flow measurements will be recorded from 3 minutes prior to spinal anesthesia placement until 3 minutes after neonatal delivery, alongside routine intermittent arm cuff measurements. Intraoperative maternal events and hemodynamic parameters will be documented, and neonatal outcome data-including Apgar scores, need for airway support, and NICU admission-will be extracted from the electronic medical record. No additional interventions beyond standard care will be performed, and all data collected will be used to compare the predictive performance of upper versus lower extremity hemodynamic measurements for neonatal outcomes.