Continuous Blood Pressure Monitoring with Hypotension Prediction for Epidural Labor Analgesia Induced Hypotension: A Randomized Controlled Trial

Introduction: Hypotension following epidural labor analgesia (ELA) is its most common complication, affecting approximately 20% of patients and posing risks to both maternal and fetal health. As digital tools and predictive analytics increasingly shape perioperative and obstetric anesthesia practices, real-world implementation data are needed to guide their integration into clinical care. Current monitoring practices rely on intermittent non-invasive blood pressure (NIBP) measurements, which may delay recognition and treatment of hypotension. The Hypotension Prediction Index (HPI) algorithm uses continuous arterial waveform monitoring to predict hypotension for potentially earlier intervention. This clinical trial evaluated the feasibility, acceptability, and efficacy of continuous HPI-guided treatment in reducing time-to-treatment for ELA-associated hypotension and improving maternal hemodynamics. Methods: This was a prospective randomized controlled trial design involving healthy pregnant individuals receiving ELA. Participants were randomized into two groups: Group CM (conventional monitoring with NIBP) and Group HPI (continuous noninvasive blood pressure monitoring). In Group HPI, hypotension treatment was guided by HPI output; in Group CM, treatment was based on NIBP readings. Feasibility, appropriateness, and acceptability outcomes were assessed among subjects and their bedside nurse using the Acceptability of Intervention Measure (AIM), Intervention Appropriateness Measure (IAM), and Feasibility of Intervention Measure (FIM) instruments. The primary efficacy outcome was time-to-treatment of hypotension, defined as the duration between onset of hypotension and administration of a vasopressor or fluid therapy. This outcome was chosen to evaluate the clinical responsiveness enabled by HPI monitoring. Hypotension defined as a mean arterial pressure (MAP) < 65 mmHg for more than 1 minute in Group CM and an HPI threshold < 75 for more than 1 minute in group HPI. Secondary outcomes included total time in hypotension, vasopressor doses, and hemodynamic parameters. Results: There were 30 patients (Group HPI n=16; Group CM n=14) included in the final analysis. Subjects and clinicians alike rated the acceptability, appropriateness, and feasibility of the continuous monitoring device highly. The cumulative probability of time-to-treatment of hypotension was lower by 75 minutes after ELA initiation in Group HPI (65%) than Group CM (71%), although this difference was not statistically significant (log-rank P = 0.66). Mixed models indicated trends that Group HPI had higher cardiac output (β=0.58, 95% Confidence Interval -0.18 to 1.34, P=0.13) and lower systemic vascular resistance (β= -97.22, 95% Confidence Interval -200.84 to 6.40, P=0.07) throughout the monitoring period. No differences were found in total vasopressor use or intravenous fluid administration. Conclusion: Continuous monitoring and precision hypotension treatment is feasible, appropriate, and acceptable to both patients and clinicians in a labor and delivery setting. HPI-guided treatment was associated with hemodynamic trends that warrant further investigation.