Pilot Study of Real-Time Blood Pressure Decision Support During Cesarean Delivery Under Spinal Anesthesia

Open-Label Pilot Study of a Clinician-Facing Decision-Support Algorithm for Blood Pressure Forecasting During Cesarean Delivery Under Spinal Anesthesia

This single-center, open-label pilot study evaluates a clinician-facing decision-support algorithm that displays real-time forecasts of maternal mean arterial pressure (MAP), a measure of blood pressure, during elective cesarean delivery under spinal anesthesia. The display provides 1-, 2-, and 3-minute MAP forecasts from the time of spinal anesthesia administration until delivery or up to 20 minutes, whichever occurs first. Clinicians continue to manage blood pressure according to usual institutional practice, including phenylephrine infusion and bolus dosing, and retain full autonomy over treatment decisions; the study display does not provide dosing recommendations. The primary objective is to assess the prospective accuracy of short-horizon MAP forecasts. Secondary outcomes assess intraoperative hypotension burden and phenylephrine exposure during the observation window, including exploratory comparison with matched nonconcurrent controls.

Study Overview

• Status: Completed
• Conditions: Spinal Hypotension
• Intervention / Treatment: Other: ARX Decision-Support Display

Detailed Description

This single-center, open-label, single-group pilot study evaluated the prospective performance and operating-room feasibility of a clinician-facing autoregressive with exogenous input (ARX) decision-support algorithm for short-horizon maternal blood pressure forecasting during elective cesarean delivery under spinal anesthesia. Adult pregnant patients at term undergoing elective cesarean delivery with planned spinal anesthesia and prophylactic phenylephrine management were enrolled at a tertiary care academic hospital.

The ARX system generated real-time forecasts of maternal mean arterial pressure (MAP) at 1-, 2-, and 3-minute horizons from the time of spinal anesthesia administration until delivery or 20 minutes, whichever occurred first. The model used prior MAP values together with time-stamped phenylephrine infusion and bolus dosing and intrathecal bupivacaine dose/time as inputs. Forecasts were displayed on a dedicated screen adjacent to the anesthesia workstation. The display was intended to support clinician awareness of short-horizon hemodynamic trends and did not provide dosing recommendations. Blood pressure management remained under usual clinical care, including phenylephrine infusion and bolus administration according to institutional practice, and treating anesthesiologists retained full autonomy over all management decisions.

The primary objective was to assess prospective forecast accuracy at each prediction horizon using the difference between predicted and observed MAP during the study observation window. Additional analyses assessed other forecast-accuracy metrics, short-horizon identification of hypotension defined as MAP below 80% of baseline, and implementation feasibility based on uninterrupted display operation and clinician-reported overrides. Baseline MAP was defined as the mean of the last three pre-spinal noninvasive blood pressure measurements. Baseline MAP was defined as the mean of the last three pre-spinal noninvasive blood pressure measurements. Noninvasive blood pressure was recorded at 1-minute intervals, and model inputs were entered in real time by in-room research staff. Secondary outcomes assessed intraoperative hypotension burden and phenylephrine exposure during the observation window, including exploratory comparison with matched nonconcurrent controls; these analyses were not part of prospective assignment to the study intervention.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Brigham and Women's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adult pregnant individuals (≥18 years old) presenting for elective or scheduled cesarean delivery.
2. ASA physical status 2 or 3 (obstetric patients without severe comorbidities).
3. Singleton pregnancy at term (≥37 weeks gestation).
4. Planned spinal anesthesia for cesarean delivery with phenylephrine infusion (and/or boluses) as the primary vasopressor.
5. Able to provide informed consent.
6. No known fetal anomalies or intrauterine demise.

Exclusion Criteria:

1. Pre-existing or gestational hypertensive disorders (e.g., chronic hypertension, preeclampsia, eclampsia) or use of cardiovascular medications that can affect blood pressure or heart rate (e.g.

   propranolol for migraine)

2. Known major cardiovascular disease or arrhythmias requiring treatment (e.g., heart failure, significant valvular disease).
3. Planned use of non-phenylephrine vasopressors (e.g., ephedrine, norepinephrine) for routine BP management.
4. Allergy or contraindication to bupivacaine or phenylephrine.
5. Urgent or emergent cesarean delivery (where time constraints may not allow for adequate data collection or informed consent).
6. Inability to cooperate with protocol procedures.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: ARX Decision-Support Display; Participants undergoing elective cesarean delivery under spinal anesthesia received standard clinical management plus a clinician-facing ARX decision-support display that showed 1-, 2-, and 3-minute forecasts of maternal mean arterial pressure from spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first. The display did not provide dosing recommendations. Phenylephrine infusion and bolus dosing remained under clinician direction according to institutional practice.

Other: ARX Decision-Support Display; A clinician-facing decision-support display that presented real-time 1-, 2-, and 3-minute forecasts of maternal mean arterial pressure during elective cesarean delivery under spinal anesthesia, from spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first. The display did not provide dosing recommendations. Phenylephrine infusion and bolus dosing remained under clinician direction according to institutional practice

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Root Mean Square Error of 1-Minute-Ahead Mean Arterial Pressure Forecast	Patient-level mean root mean square error (RMSE) between algorithm-predicted and observed maternal mean arterial pressure (MAP) for the 1-minute forecast horizon using minute-level intraoperative data.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.
Root Mean Square Error of 2-Minute-Ahead Mean Arterial Pressure Forecast	Patient-level mean root mean square error (RMSE) between algorithm-predicted and observed maternal mean arterial pressure (MAP) for the 2-minute forecast horizon using minute-level intraoperative data.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.
Root Mean Square Error of 3-Minute-Ahead Mean Arterial Pressure Forecast	Patient-level mean root mean square error (RMSE) between algorithm-predicted and observed maternal mean arterial pressure (MAP) for the 3-minute forecast horizon using minute-level intraoperative data.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Maternal Hypotension During the Observation Window	Presence of at least one maternal mean arterial pressure measurement below 80% of baseline during the observation window; exploratory comparison with matched nonconcurrent controls.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.
Duration of Maternal Hypotension During the Observation Window	Cumulative minutes with maternal mean arterial pressure below 80% of baseline during the observation window; exploratory comparison with matched nonconcurrent controls.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.
Total Phenylephrine Dose During the Observation Window	Total phenylephrine dose calculated as the sum of all bolus doses plus infusion dose integrated over time during the observation window; exploratory comparison with matched nonconcurrent controls.	From spinal anesthesia administration until delivery or up to 20 minutes, whichever occurred first.

Collaborators and Investigators

• Sponsor: Brigham and Women's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): June 16, 2025
• Primary Completion (Actual): July 16, 2025
• Study Completion (Actual): July 16, 2025

Study Registration Dates

• First Submitted: April 10, 2026
• First Submitted That Met QC Criteria: April 10, 2026
• First Posted (Actual): April 16, 2026

Study Record Updates

• Last Update Posted (Actual): April 16, 2026
• Last Update Submitted That Met QC Criteria: April 10, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: phenylephrine; cesarean delivery; decision support; autoregressive with exogenous input
• Other Study ID Numbers: 2025P000588

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No