The Effect of BIPAP on Diaphragmatic Function

Official title

The Effects of Biphasic Positive Airway Pressure (BIPAP) Use on Diaphragm Functions in Patients With Chronic Obstructive Pulmonary Disease (COPD)

Overview

This research is designed to evaluate how long-term treatment with Bilevel Positive Airway Pressure (BiPAP) influences diaphragm function in patients with Chronic Obstructive Pulmonary Disease (COPD) who suffer from chronic hypercapnic respiratory failure. The diaphragm is the primary muscle of breathing, and its dysfunction is linked to unfavorable clinical outcomes such as higher mortality rates and frequent hospitalizations. In this prospective cohort study, COPD patients starting BiPAP therapy based on clinical indication will be monitored through repeated ultrasound assessments of diaphragm structure and function together with pulmonary function testing, respiratory muscle strength evaluation, dyspnea. The main outcome of interest is the change in diaphragm thickness in inspiration, thickness in expiration, diaphragm thickening fraction (DTF), diaphragm maximum contraction velocity and maximum relaxation velocity across a 6 weeks as a early time and 12 months for long time follow-up period. Secondary measures include hospital admissions, and one-year survival. The study is expected to generate valuable evidence about the link between non-invasive ventilation and diaphragm function, which may contribute to optimizing treatment strategies for COPD patients with advanced respiratory failure.

Detailed description

Chronic Obstructive Pulmonary Disease (COPD) is a progressive respiratory condition frequently complicated by chronic hypercapnic respiratory failure. In this population, long-term non-invasive ventilation with bilevel positive airway pressure (BiPAP) is widely prescribed to improve gas exchange, relieve symptoms, and reduce the risk of hospitalizations. However, its effects on diaphragm function, the main respiratory muscle, remain poorly understood. Diaphragm dysfunction in COPD has been associated with adverse outcomes including increased mortality, prolonged hospital stay, and higher readmission rates.

This prospective cohort study aims to evaluate the longitudinal impact of BiPAP treatment on diaphragm structure and function in patients with COPD and chronic hypercapnic respiratory failure. Eligible participants will be patients who are prescribed BiPAP therapy according to standard clinical indications. Diaphragm function will be assessed repeatedly using ultrasonography, which provides non-invasive and reliable measurements of diaphragm thickness at end-inspiration and end-expiration, thickening fraction (DTF), maximum contraction velocity, and maximum relaxation velocity. These measurements will be complemented by pulmonary function tests, respiratory muscle strength evaluations, and dyspnea assessment.

The primary outcome is the change in diaphragm ultrasound parameters (inspiratory thickness, expiratory thickness, thickening fraction, contraction velocity, and relaxation velocity) over the course of treatment. Early follow-up will occur at 6 weeks to assess short-term effects, while long-term follow-up at 12 months will provide insight into sustained adaptations to BiPAP therapy. Secondary outcomes include the frequency of hospital admissions and overall one-year survival.

By integrating functional, structural, and clinical outcomes, the study is expected to provide novel evidence on the role of non-invasive ventilation in modifying diaphragm performance. Findings may contribute to refining treatment strategies and optimizing long-term management of COPD patients with advanced respiratory failure.

Interventions

• Device BIPAP
  After BIPAP Prescribed By A Physician, Diaphragmatic Functions Will Be Evaluated With Ultrasound In The Early And Late Periods

Primary outcome measures

• One-Year Survival [Time frame: at baseline and after 12 months]
• Number of Hospital Admissions within 12 Months [Time frame: at baseline and after 12 months]
• Maximum Inspiratory Pressure (MIP) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year]
• Maximum Expiratory Pressure (MEP) [Time frame: At baseline, after 6 weeks of BiPAP usage, and after one year.]
• Forced Vital Capacity (FVC) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]
• Forced Expiratory Volume in 1 Second (FEV₁) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]
• FEV₁/FVC Ratio [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]
• Cough Strength (Peak Cough Flow, PCF) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]
• Diaphragm Thickness (B-mode Ultrasound) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]
• Diaphragm Excursion (M-mode Ultrasound) [Time frame: Baseline, after 6 weeks of BiPAP usage, and after one year.]

Secondary outcome measures (2)

• COPD Assessment Test (CAT) Score: [Time frame: at baseline and after 6 weeks of BIPAP usage and after one year]
• Dyspnea (mMRC Scale) [Time frame: at baseline and after 6 weeks of BIPAP usage and after one year]

Eligibility criteria

Inclusion criteria

• Being between 40-80 years of age,
• Having a diagnosis of stable COPD for at least 1 year,
• Being in a stable phase (no acute exacerbation within the last 4 weeks),
• Meeting the GOLD 2025 A-B-E classification according to symptoms and exacerbation history,
• Having been initiated on BiPAP therapy with a clinical indication,
• Being willing to participate in the study and providing informed consent.

Exclusion criteria

• Pregnancy,
• Diaphragmatic paralysis,
• Neuromuscular and neurological diseases,
• Decompensated heart failure,
• Chest deformity,
• Acute exacerbation within the last month,
• Pneumothorax,
• Body mass index greater than 35 kg/m²,
• Long-term corticosteroid use,
• Chemotherapy,
• Active malignancy,
• Inability to cooperate,
• Thoracoabdominal surgery within the last 3 months.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

Turkey (Türkiye) · 1 center

• Demiroglu Bilim University, Department of Physiotherapy and Rehabilitation — Istanbul

Identifiers

NCT: NCT07193017 · Effect of BIPAP on diaphragm

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗