The Impact of Volume Overload on Obstructive Sleep Apnea in Patients With Congestive Heart Failure

May 19, 2026 updated by: Itshak Amsalem

The goal of this observational study is to learn how removing extra fluid from the body (diuresis) affects sleep apnea in adults hospitalized with heart failure.

The main questions it aims to answer are:

Does sleep apnea severity improve after fluid removal? Is the improvement in sleep apnea related to the amount of fluid removed? Do changes in neck size reflect changes in sleep apnea severity?

Participants admitted to the hospital with heart failure and fluid overload will take part in this study.

Participants will:

Use a wearable sleep monitoring device (WatchPAT) on the first night of hospitalization Use the device again after fluid removal, when the treating cardiologist determines that the patient is no longer fluid overloaded Have their neck circumference measured before and after fluid removal Have their weight and fluid balance recorded during hospitalization Have routine blood tests and clinical assessments as part of standard care

Researchers will compare each participant's results before and after fluid removal to see if sleep apnea improves and whether these changes are linked to fluid removal and changes in neck circumference.

Study Overview

Status

Recruiting

Conditions

Study Type

Observational

Enrollment (Estimated)

50

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Israel
      • Jerusalem, Israel
        • Recruiting
        • Shaare Zedek Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adults admitted with decompensated heart failure and clinical fluid overload, including both preserved and reduced ejection fraction. Participants will be recruited during hospitalization in a dedicated heart failure unit and followed prospectively with sleep monitoring and clinical assessments before and after achievement of clinical euvolemia.

Description

Inclusion Criteria:

  • Adults aged 18 years or older
  • Hospitalized with decompensated heart failure and clinical evidence of fluid overload
  • Diagnosis of heart failure (reduced or preserved ejection fraction)
  • Clinically indicated for diuretic therapy
  • Able to undergo sleep apnea assessment using the WatchPAT device
  • Able to provide informed consent

Exclusion Criteria:

  • Known central sleep apnea as the predominant sleep-disordered breathing type
  • Current treatment with continuous positive airway pressure (CPAP)
  • Acute respiratory failure requiring mechanical ventilation
  • Conditions preventing proper use of the WatchPAT device (e.g., severe hand or finger injury)
  • Hemodynamic instability precluding participation
  • Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Adults With Heart Failure Undergoing Diuresis
Adults hospitalized with heart failure and fluid overload who undergo standard diuretic therapy. Participants are evaluated using sleep monitoring (WatchPAT), neck circumference measurements, and clinical assessments before diuresis (on the first night of hospitalization) and after diuresis, when the treating cardiologist determines that the patient is no longer fluid overloaded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in apnea-hypopnea index (AHI)
Time Frame: From first night of hospitalization to achievement of clinical euvolemia (during hospitalization), up to 30-days.
Change in obstructive sleep apnea severity, measured by the apnea-hypopnea index (AHI) using the WatchPAT device, between the first night of hospitalization (pre-diuresis) and after diuresis, when the treating cardiologist determines that the participant is no longer fluid overloaded
From first night of hospitalization to achievement of clinical euvolemia (during hospitalization), up to 30-days.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in oxygen desaturation index (ODI)
Time Frame: From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Change in oxygen desaturation index (ODI) measured by the WatchPAT device between pre-diuresis and post-diuresis assessments
From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Change in respiratory disturbance index (RDI)
Time Frame: From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Change in respiratory disturbance index (RDI), defined as the number of respiratory disturbance events per hour of sleep, measured using the WatchPAT device, between the first night of hospitalization (pre-diuresis) and after diuresis, when the treating cardiologist determines that the participant is no longer fluid overloaded
From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Correlation between change in respiratory disturbance index (RDI) and body weight change
Time Frame: From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Correlation between the change in respiratory disturbance index (RDI), measured in events per hour using the WatchPAT device, and change in body weight measured in kilograms during hospitalization
From first night of hospitalization to achievement of clinical euvolemia, up to 30-days.
Correlation between change in apnea-hypopnea index (AHI) and body weight change
Time Frame: From first night of hospitalization to achievement of clinical euvolemia, up to 30 days
Correlation between the change in apnea-hypopnea index (AHI), defined as the number of apnea and hypopnea events per hour of sleep and measured using the WatchPAT device, and change in body weight measured in kilograms during hospitalization
From first night of hospitalization to achievement of clinical euvolemia, up to 30 days
Change in neck circumference
Time Frame: From admission to achievement of clinical euvolemia, up to 30 days
Change in neck circumference, measured in centimeters using a standardized measuring tape, between pre-diuresis (at admission) and post-diuresis assessment after the treating cardiologist determines that the participant is no longer fluid overloaded
From admission to achievement of clinical euvolemia, up to 30 days
Correlation coefficient between change in neck circumference and change in apnea-hypopnea index (AHI)
Time Frame: From admission to achievement of clinical euvolemia, up to 30 days
Correlation coefficient (unitless) describing the relationship between change in neck circumference (centimeters) and change in apnea-hypopnea index (AHI), measured in events per hour using the WatchPAT device
From admission to achievement of clinical euvolemia, up to 30 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Itshak Amsalem

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2026

Primary Completion (Estimated)

January 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

April 15, 2026

First Submitted That Met QC Criteria

May 19, 2026

First Posted (Actual)

May 22, 2026

Study Record Updates

Last Update Posted (Actual)

May 22, 2026

Last Update Submitted That Met QC Criteria

May 19, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 0350-24-SZMC

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data (IPD) sharing is currently undecided. Any future data sharing will depend on institutional policies, ethical approvals, and applicable data protection regulations. If shared, only de-identified data will be made available to qualified researchers upon reasonable request.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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