Comparison of Acoustic Variability Index (AVI) and Pulse Pressure Variation (PPV) for Predicting Fluid Responsiveness in Mechanically Ventilated Patients

NCT07516470 | Completed

• 1 other identifier: SI_RESQ_02
• Study Type: observational
• Target: 122
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if a new medical device called ResQ works to predict fluid needs in adults undergoing surgery under general anesthesia. The main questions it aims to answer are:

• Can the Acoustic Variability Index (AVI) measured by ResQ predict if a participant needs more fluids as accurately as the standard arterial blood pressure-based method (PPV)?
• Is the ResQ device safe to use during surgery? Researchers will compare the new method (AVI) to the standard method (PPV) to see if ResQ provides reliable information for managing patient fluids. Participants will:
• Undergo their planned surgery as scheduled.
• Have a soft probe placed in the esophagus to monitor heart and lung sounds.
• Receive a set amount of intravenous (IV) fluid as part of their regular surgery care.
• Have their heart function checked before and after the fluids are given.

Conditions

Anesthesia, General; Fluid Responsiveness Predictability; Hemodynamic Monitoring

Keywords

Fluid Responsiveness; Hemodynamic Monitoring

Outcome Measures

Primary Outcomes (1)

• Comparison of Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) between AVI and PPV for Predicting Fluid Responsiveness (Non-inferiority)

  Assessed by calculating and comparing the Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve for both indices to predict fluid responsiveness. The non-inferiority of AVI compared to PPV will be evaluated. Fluid responsiveness is defined as a Cardiac Output (CO) increase of 10% or more following a 500 mL fluid challenge.

  Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge

Secondary Outcomes (4)

• Concordance of Respiratory Rate (RR) between ResQ and Carestation 750

  Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge.

• Comparison of Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) between AVI and PVI for Predicting Fluid Responsiveness

  Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge.

• Comparison of Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) between AVI and SVV for Predicting Fluid Responsiveness

  Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge

• Diagnostic performance of AVI for fluid responsiveness (Sensitivity, Specificity, Positive Predictive Value, Negative Predictive Value)

  Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge

Study Arms (1)

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Adult patients (aged 19 years or older) scheduled for elective major abdominal, retroperitoneal, or pelvic surgery under general anesthesia and mechanical ventilation. In this single-arm, within-subject paired-comparison cohort, each participant undergoes real-time monitoring of hemodynamic indices-specifically the Acoustic Variability Index (AVI) and Pulse Pressure Variation (PPV)-both before and after a standardized 500 mL fluid challenge. This design allows for a direct comparison of the two indices within the same physiological state for each participant.

Device: Biological Signal Processing Device for Acoustic Variability Index; Device: Patient monitor for pulse pressure variation; Device: Hemodynamic monitor for cardiac Output and stroke volume variation; Device: Patient monitor for pleth variability index; Device: Anesthesia monitoring system for respiratory rate

Interventions

Patient monitor for pulse pressure variation DEVICE

A standard multi-parameter patient monitor used to measure the reference hemodynamic index, Pulse Pressure Variation (PPV), via an arterial catheter

Also known as: GE CARESCAPE Monitor B850

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Patient monitor for pleth variability index DEVICE

A patient monitoring system used to measure the Pleth Variability Index (PVI) via a non-invasive sensor attached to the finger or toe

Also known as: Masimo Root Monitor

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Anesthesia monitoring system for respiratory rate DEVICE

An anesthesia delivery and monitoring system used to provide the reference Respiratory Rate (RR) measurement based on end-tidal CO2 (EtCO2) waveforms during general anesthesia

Also known as: GE Carestation 750

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Biological Signal Processing Device for Acoustic Variability Index DEVICE

A biosignal processing device that measures AVI and RR continuously in real-time. It analyzes heart and lung sounds collected via a general-purpose internal probe inserted into the patient's esophagus.

Also known as: SH-ResQ-01, ResQ

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Hemodynamic monitor for cardiac Output and stroke volume variation DEVICE

A specialized hemodynamic monitoring system used to measure the reference standard for fluid responsiveness: Cardiac Output (CO) and Stroke Volume Variation (SVV)

Also known as: Edwards HemoSphere Monitor

Mechanically Ventilated Surgical Patients (Paired-Comparison)

Eligibility Criteria

• Age: 19 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult patients at Asan Medical Center in Seoul, South Korea. Participants will be recruited from the patients scheduled to undergo elective major surgeries involving organs in the abdominal, retroperitoneal, or pelvic cavities (such as hepatobiliary, pancreatic, intestinal, renal, or uterine procedures). These patients will be receiving general anesthesia and mechanical ventilation and are expected to require continuous intraoperative hemodynamic monitoring as part of their standard surgical care.

You may qualify if:

• To participate in this study, individuals must meet all of the following criteria:
• Adults aged 19 years or older.
• If female, not pregnant or breastfeeding.
• Scheduled for a planned surgery of major organs in the abdominal, retroperitoneal, or pelvic cavities (e.g., hepatobiliary and pancreatic, small intestine, large intestine, kidney, uterus) under general anesthesia with mechanical ventilation

You may not qualify if:

• Scheduled to receive mechanical ventilation in a volume-controlled or pressure-controlled mode in the operating room or intensive care unit, with an anticipated tidal volume of 6-8 mL/kg (Ideal Body Weight), respiratory rate of 8-14 breaths/min, and PEEP of 0-5 cmH2O
• Scheduled for hemodynamic monitoring to measure the comparison indices during surgery
• Able to understand the study's purpose and procedures and communicate clearly with the investigator and research staff
• Voluntarily signed the written informed consent form before participating in the study
• Individuals meeting any of the following criteria will be excluded from participation:
• Undergoing emergency or unplanned surgery
• Anticipated to have difficulty with the application of general anesthesia or mechanical ventilation
• Anticipated to experience massive bleeding of 1 L or more during surgery.
• Undergoing a reoperation due to the same underlying disease
• History of severe esophageal damage (e.g., esophageal varices or stricture) that makes inserting the probe difficult
• Inability to have an arterial catheter inserted, making the measurement of Stroke Volume Variation (SVV) and Pulse Pressure Variation (PPV) difficult
• Condition where a fluid challenge is contraindicated or considered high risk (e.g., clinical signs of fluid overload, pulmonary congestion, or pulmonary edema; acute exacerbation of heart failure or renal failure; or a hemodynamically unstable state)
• Body Mass Index (BMI) greater than 30 kg/m²
• Uncontrolled coagulopathy prior to surgery (e.g., Platelet count \< 100,000/μL or INR \> 2)
• Arrhythmias, such as atrial fibrillation/flutter or premature atrial/ventricular contractions (\>2 per 10 seconds), that make it difficult for the variability index to operate accurately

Sponsors & Collaborators

• Signal House Co., Ltd.: lead
• Ministry of SMEs and Startups, Korea: collaborator

Study Sites (1)

Asan Medical Center

Seoul, Seoul, 05505, South Korea

Location

MeSH Terms

Interventions

Monitoring, Physiologic; Hemodynamic Monitoring; Cardiac Output; Respiratory Rate

Intervention Hierarchy (Ancestors)

Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Cardiovascular; Heart Function Tests; Hemodynamics; Cardiovascular Physiological Phenomena; Circulatory and Respiratory Physiological Phenomena; Vital Signs; Physical Examination; Respiration; Respiratory Physiological Phenomena

Study Officials

• Hye-Mee Kwon, MD, PhD

  Asan Medical Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: CASE ONLY
• Time Perspective: PROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 24, 2026
• First Posted: April 8, 2026
• Study Start: April 13, 2026
• Primary Completion: July 9, 2026
• Study Completion: July 14, 2026
• Last Updated: July 17, 2026

Record last verified: 2026-07

Locations

KR (1)