Fluid Responsiveness PredictabilityNCT07516470
Comparison of Acoustic Variability Index (AVI) and Pulse Pressure Variation (PPV) for Predicting Fluid Responsiveness in Mechanically Ventilated Patients
An observational study of Fluid Responsiveness Predictability and Hemodynamic Monitoring, run by Signal House Co., Ltd. at 1 site in South Korea.
Trial 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… Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Fluid Responsiveness Predictability, Hemodynamic Monitoring, Anesthesia, General
- What is being tested?
- Biological Signal Processing Device for Acoustic Variability Index, Patient monitor for pulse pressure variation and Hemodynamic monitor for cardiac Output and stroke volume variation
- Type of treatment
- Medical device
- How many people
- 122 participants
- Where
- 1 siteSouth Korea
- Study dates
- 13 Apr 2026to 14 Jul 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
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.
Who may be able to join
- 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
- Classified as American Society of Anesthesiologists (ASA) Class I, II, or III. (Note: Excluded regardless of class if any exclusion criteria are met)
- 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
Show all 9Show fewer
- 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
Who cannot join
- 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
Show all 14Show fewer
- 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
- Other cardiovascular history that makes accurate cardiac output measurement impossible (e.g., severe valvular disease, history of intracardiac shunt surgery, or structural heart surgery)
- Pregnant or lactating women
- Any other condition deemed unsuitable for study participation by the investigator
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Prospective, Single-Center, Single-Arm, Paired-Comparison, Open-Label, Non-Inferiority Confirmatory Trial to Evaluate the Efficacy and Safety of ResQ by Comparing Fluid Responsiveness Prediction Performance of the Acoustic Variability Index (AVI) Versus Pulse Pressure Variation (PPV) in Mechanically Ventilated Patients
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.
Read more
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.
- Being tested
- Biological Signal Processing Device for Acoustic Variability Index, Patient monitor for pulse pressure variation, Hemodynamic monitor for cardiac Output and stroke volume variation, Patient monitor for pleth variability index, Anesthesia monitoring system for respiratory rate
- Keywords
- Fluid Responsiveness, Hemodynamic Monitoring
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Biological Signal Processing Device for Acoustic Variability IndexDevice
Also called SH-ResQ-01, ResQ
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.
Patient monitor for pulse pressure variationDevice
Also called GE CARESCAPE Monitor B850
A standard multi-parameter patient monitor used to measure the reference hemodynamic index, Pulse Pressure Variation (PPV), via an arterial catheter
Hemodynamic monitor for cardiac Output and stroke volume variationDevice
Also called Edwards HemoSphere Monitor
A specialized hemodynamic monitoring system used to measure the reference standard for fluid responsiveness: Cardiac Output (CO) and Stroke Volume Variation (SVV)
Patient monitor for pleth variability indexDevice
Also called Masimo Root Monitor
A patient monitoring system used to measure the Pleth Variability Index (PVI) via a non-invasive sensor attached to the finger or toe
Anesthesia monitoring system for respiratory rateDevice
Also called GE Carestation 750
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
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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 |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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
Assessed by evaluating the agreement of respiratory rate (RR) measurements between the ResQ device and the reference anesthesia workstation (Carestation 750).
Measured: 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
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. Fluid responsiveness is defined as a Cardiac Output (CO) increase of 10% or more following a 500 mL fluid challenge.
Measured: 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
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. Fluid responsiveness is defined as a Cardiac Output (CO) increase of 10% or more following a 500 mL fluid challenge.
Measured: 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)
Assessed by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) based on the optimal cut-off value determined by ROC curve analysis to evaluate the diagnostic performance of AVI.
Measured: Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Apr 2026
- Study start13 Apr 2026
- Primary completion9 Jul 2026
- Study completion14 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fluid Responsiveness PredictabilityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 122 participants (actual)
Sponsor and investigators
- Lead sponsor
- Signal House Co., Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Ministry of SMEs and Startups, Korea
- Responsible party
- Sponsor
- Investigators
- Hye-Mee Kwon, MD, PhD, Principal investigator, Asan Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07516470
- Sponsor's protocol ID
- SI_RESQ_02
- Status last verified
- Jul 2026
- First submitted
- 24 Mar 2026
- Last updated
- 17 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: A decision on whether to share Individual Participant Data (IPD) has not yet been made. The sponsor and investigators are currently evaluating the data sharing policy, and this record will be updated once a formal decision is reached.
Study at a glance
From the registry record, last updated by the sponsor on 17 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Prospective, Single-Center, Single-Arm, Paired-Comparison, Open-Label, Non-Inferiority Confirmatory Trial to Evaluate the Efficacy and Safety of ResQ by Comparing Fluid Responsiveness Prediction Performance of the Acoustic Variability Index (AVI) Versus Pulse Pressure Variation (PPV) in Mechanically Ventilated Patients
- ClinicalTrials.gov ID
- NCT07516470
- Acronym / sponsor ID
- SI_RESQ_02
- Keywords
- Fluid Responsiveness, Hemodynamic Monitoring
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 122 participants (actual)
- Lead sponsor
- Signal House Co., Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Ministry of SMEs and Startups, Korea
- Study start
- 13 Apr 2026 (actual)
- Primary completion
- 9 Jul 2026 (actual)
- Study completion
- 14 Jul 2026 (actual)
- First posted
- 8 Apr 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Mechanically Ventilated Surgical Patients (Paired-Comparison) | – | 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 rateAdult 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. |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (9 listed)
- 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
- Classified as American Society of Anesthesiologists (ASA) Class I, II, or III. (Note: Excluded regardless of class if any exclusion criteria are met)
- 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
Key exclusion criteria (14 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Biological Signal Processing Device for Acoustic Variability IndexAlso: SH-ResQ-01, ResQA 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. | Device | Mechanically Ventilated Surgical Patients (Paired-Comparison) |
| Patient monitor for pulse pressure variationAlso: GE CARESCAPE Monitor B850A standard multi-parameter patient monitor used to measure the reference hemodynamic index, Pulse Pressure Variation (PPV), via an arterial catheter | Device | Mechanically Ventilated Surgical Patients (Paired-Comparison) |
| Hemodynamic monitor for cardiac Output and stroke volume variationAlso: Edwards HemoSphere MonitorA specialized hemodynamic monitoring system used to measure the reference standard for fluid responsiveness: Cardiac Output (CO) and Stroke Volume Variation (SVV) | Device | Mechanically Ventilated Surgical Patients (Paired-Comparison) |
| Patient monitor for pleth variability indexAlso: Masimo Root MonitorA patient monitoring system used to measure the Pleth Variability Index (PVI) via a non-invasive sensor attached to the finger or toe | Device | Mechanically Ventilated Surgical Patients (Paired-Comparison) |
| Anesthesia monitoring system for respiratory rateAlso: GE Carestation 750An anesthesia delivery and monitoring system used to provide the reference Respiratory Rate (RR) measurement based on end-tidal CO2 (EtCO2) waveforms during general anesthesia | Device | Mechanically Ventilated Surgical Patients (Paired-Comparison) |
Primary outcome
Comparison of Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) between AVI and PPV for Predicting Fluid Responsiveness (Non-inferiority)
Time frame: Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge
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.
4 secondary outcomes
Concordance of Respiratory Rate (RR) between ResQ and Carestation 750
Time frame: 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
Time frame: 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
Time frame: 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)
Time frame: Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jul 2026.
- Individual participant dataSharing planned: Undecided. A decision on whether to share Individual Participant Data (IPD) has not yet been made. The sponsor and investigators are currently evaluating the data sharing policy, and this record will be updated once a formal decision is reached.
Related trials for Fluid Responsiveness Predictability
Recruiting
A Study Comparing Carotid Doppler Ultrasound and Echocardiography to Assess Fluid Responsiveness in Septic Patients on Ventilator
Fluid Responsiveness Predictability in Sepsis
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Hye-Mee Kwon, MD, PhD principal investigator
Asan Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Fluid Responsiveness Predictability and Hemodynamic Monitoring, run by Signal House Co., Ltd. at 1 site in South Korea.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in South Korea. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Comparison of Area Under the Receiver Operating Characteristic (ROC) Curve (AUC) between AVI and PPV for Predicting Fluid Responsiveness (Non-inferiority) (time frame: Baseline (assessed continuously for 3 minutes before fluid challenge) and 3 minutes after a 500 mL fluid challenge). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jul 2026.