Autoregressive With Exogenous Input (ARX) Decision Support for Blood Pressure Maintenance During Cesarean Delivery Under Spinal Anesthesia: A Prospective Pilot Study With Matched Nonconcurrent Controls

Background: Spinal anesthesia for cesarean delivery commonly causes maternal hypotension, which may compromise uteroplacental perfusion and maternal comfort. Guidelines recommend maintaining maternal blood pressure near baseline with prophylactic vasopressor strategies, yet titration remains reactive. We evaluated an autoregressive with exogenous input (ARX) decision-support algorithm that provides real-time forecasts of maternal mean arterial pressure (MAP) to support vasopressor management during cesarean delivery under spinal anesthesia. Methods: In this single-center, open-label, prospective pilot study, 20 pregnant patients at term undergoing elective cesarean delivery under spinal anesthesia received standard care supplemented by ARX-generated MAP predictions at 1-, 2- and 3-minute horizons. Clinicians titrated phenylephrine per institutional protocol while reviewing ARX predictions, retaining full autonomy for dosing decisions. Predictive performance was quantified using root mean square error (RMSE), mean absolute error (MAE), coefficient of determination (R²), and fraction of improvement in total error (FIT). ARX-guided patients were matched 1:2 to nonconcurrent controls (n = 40) on attending anesthesiologist and intrathecal bupivacaine dose, with nearest-neighbor matching on age and body mass index. Exploratory outcomes included hypotension (MAP