Effectiveness of Hypotension Prediction Index (HPI) in Preventing Hypotension in the Post-Anesthesia Care Unit (PACU)

Effectiveness of Hypotension Prediction Index (HPI) in Preventing Hypotension in the Post-Anesthesia Care Unit (PACU): A Prospective, Randomized, Controlled Trial

Postoperative hypotension in the post-anesthesia care unit (PACU) is common and linked to adverse outcomes. The Hypotension Prediction Index (HPI) predicts hypotensive events intraoperatively, but its PACU application is unexplored. This study aims to investigate the effectiveness of HPI-guided monitoring in preventing PACU hypotension.

Study Overview

• Status: Completed
• Conditions: Postoperative Complications; Hypotension
• Intervention / Treatment: Device: Hypotension Prediction Index Monitoring; Other: Standard PACU Monitoring

Detailed Description

Study Design This prospective, randomized, controlled, single-center trial will be conducted in the PACU of a tertiary care hospital. The study aims to evaluate the effectiveness of HPI in preventing postoperative hypotension. All procedures follow institutional protocols, and the trial is designed to reduce bias through randomization and stratification.

Study Population Eligible patients are adults (≥ 19 years) undergoing elective surgery under general anesthesia, with arterial catheters in place and an expected PACU stay of ≥ 30 minutes. Exclusion criteria include immediate postoperative ICU admission, use of vasopressors during anesthesia emergence, ASA physical status V, or contraindications to arterial monitoring. These criteria ensure a focus on patients suitable for PACU monitoring with arterial lines. The study population is representative of high-risk surgical patients requiring advanced hemodynamic monitoring.

Intervention Patients will be randomized 1:1 to the HPI group, which receives continuous HPI monitoring (Edwards Lifesciences HemoSphere platform, Irvine, CA, USA) with interventions such as fluid boluses or vasopressors if HPI is ≥ 85 per protocol, or to the control group, which receives standard PACU monitoring including non-invasive blood pressure, heart rate, and oxygen saturation. The interventions in the HPI group follow institutional guidelines to ensure consistency, while the control group receives routine PACU monitoring practices. Randomization will be used in a computer-generated sequence, stratified by ASA class (I-II vs. III-IV) to balance risk profiles.

Outcomes The primary outcome is the incidence of hypotension (mean arterial pressure [MAP] < 65 mmHg for more than 1 minute) during the PACU stay. Secondary outcomes include time to the first hypotensive episode, total duration of hypotension, vasopressor and fluid administration (frequency and dose), PACU stay duration, and postoperative complications such as nausea and acute kidney injury. Acute kidney injury (AKI) in the PACU was defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria, specifically as an increase in serum creatinine by ≥ 0.3 mg/dL within 48 hours of surgery or an increase to ≥1.5 times baseline within 7 days, assess via blood samples collect during or immediately after the PACU stay. Urine output criteria are not used due to the short PACU duration and inconsistent catheterization. These outcomes are selected to evaluate both the effectiveness and impact of the HPI on clinical management. Complications are monitored to assess safety and secondary effects.

• Study Type: Interventional
• Enrollment (Actual): 210
• Phase: Not Applicable

Contacts and Locations

Study Locations

• South Korea
  • Jeollabukdo
    • Iksan, Jeollabukdo, South Korea, 54538
      • Wonkwag UH

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age ≥ 19 years
• Undergoing elective surgery under general anesthesia
• Presence of intra-arterial catheter at the end of surgery
• Expected PACU stay of ≥ 30 minutes
• Provided written informed consent

Exclusion Criteria:

• Immediate postoperative ICU admission
• Use of vasopressors during emergence from anesthesia
• ASA physical status classification of V
• Known contraindications to arterial line placement
• Participation in another interventional study within 30 days

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: HPI-guided Monitoring; Participants in this group will receive continuous Hypotension Prediction Index (HPI) monitoring using the Edwards Lifesciences HemoSphere platform. Interventions such as fluid boluses or vasopressors will be administered when HPI ≥ 85, following institutional protocols.	Device: Hypotension Prediction Index Monitoring; HPI monitoring is performed using the Edwards Lifesciences HemoSphere platform to provide real-time hypotension prediction based on arterial pressure waveform analysis. Interventions such as fluid bolus or vasopressor are administered per protocol when HPI ≥ 85.; Other Names: HPI Monitoring
Active Comparator: Control Group; Participants in this group will receive standard post-anesthesia care unit (PACU) monitoring, including non-invasive blood pressure, heart rate, and oxygen saturation. Interventions will follow usual care without guidance from HPI.	Other: Standard PACU Monitoring; Standard monitoring in the post-anesthesia care unit (PACU), including non-invasive blood pressure, heart rate, and oxygen saturation measurements. No Hypotension Prediction Index (HPI) monitoring is used. Interventions are performed according to routine institutional practices.; Other Names: Usual Care

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Postoperative Hypotension in the PACU	Defined as mean arterial pressure (MAP) < 65 mmHg lasting for more than 1 minute during the patient's stay in the post-anesthesia care unit (PACU).	From PACU admission to discharge, typically within 90 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to First Hypotensive Episode	Time elapsed from PACU admission to the first hypotensive episode (MAP < 65 mmHg for >1 minute).	From PACU admission until first hypotensive event
Vasopressor Use	Percentage of patients receiving any vasopressor during PACU stay.	From PACU admission until first hypotensive episode, assessed up to 2 hours
PACU Length of Stay	Total duration (in minutes) of PACU stay.	Duration of PACU stay, typically 30 to 90 minutes
Incidence of Postoperative Complications	Occurrence of postoperative complications during PACU stay, including nausea/vomiting and acute kidney injury as defined by KDIGO criteria.	Within 24 hours after PACU admission

Collaborators and Investigators

• Sponsor: Wonkwang University Hospital
• Investigators: Principal Investigator: Cheol Lee, M.D.,Ph.D, Department of anesthesiology and pain medicine, Wonkwang University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): May 6, 2025
• Primary Completion (Actual): June 2, 2025
• Study Completion (Actual): July 11, 2025

Study Registration Dates

• First Submitted: July 15, 2025
• First Submitted That Met QC Criteria: July 24, 2025
• First Posted (Actual): July 31, 2025

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: PACU; Hemodynamic Monitoring; Hypotension Prediction Index (HPI); Arterial Pressure Waveform; HemoSphere
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Hypotension; Postoperative Complications
• Other Study ID Numbers: WonkwangUH21

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: Yes
• product manufactured in and exported from the U.S.: Yes