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NCT Number: NCT06390631

Effect of CPAP on Respiratory Load in COPD

Both intrinsic positive end expiratory pressure (PEEPi) and dynamic hyperinflation are considered as inspiratory loads which increase work of breathing in patients with COPD. The application of extrinsic positive end expiratory pressure (PEEPe) supplied by CPAP has been claimed to reduce inspiratory load based on change in esophageal pressure which could be significantly affected by change in lung volume and airflow. The investigator hypothesized that CPAP could increase respiratory load because it increases lung volume.

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Key information

Conditions

Chronic Obstructive Pulmonary Disease Chronic Disease Disease Attributes Lung Diseases Lung Diseases, Obstructive Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Disease, Chronic Obstructive Respiratory Tract Diseases

Age range

40 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Guangzhou Medical University

Guangzhou, Guangdong, China

About this study

Objective: To assess the effect of CPAP on respiratory load and lung volume in stable COPD. Methods: Patients with COPD were recruited to breath under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O). Diaphragm EMG, esophageal pressure (Pes) and transdiaphragmatic pressure (Pdi) were recorded using balloon esophageal electrode catheter (Yinghui, Guangzhou, China). End inspiratory lung volume (EILV) was measured directly from a pneumotachograph combined with a three way valve under the different CPAP levels. Sensation of breathing difficulty was also assessed. In an additional study, the effect of airflow on pressure was investigated by a physical mode.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Willing to participate after informed consent
  • Males and females, any race and aged 40-80 years
  • GOLD II-IV COPD (post-bronchodilator FEV1 < 80 % of the predicted normal, and a post-bronchodilator FEV1/FVC < 0.70)

Exclusion criteria

  • Patients recovering from acute exacerbation less than 4 weeks.
  • Patients with concomitant pulmonary disease (e.g. lung fibrosis, interstitial lung disorder).

Treatment and study plan

Continuous Positive Airway Pressure

Device

Patients with COPD were recruited to breath under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O).

Primary outcomes

  1. Diaphragm EMG

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of the electrical activity of the diaphragm (EMG-di)

  2. Lung volume

    Time frame: 1-3 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O)

    measurement of end inspiratory lung volume (EILV)

  3. Intrinsic positive end expiratory pressure (PEEPi)

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    PEEPi was calculated from the negative deflection in Pes from the onset of inspiratory effort to the point of zero flow during spontaneous breathing.

  4. Inspiratory pressure

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of esophageal pressure and transdiaphragmatic pressure by caculating tidal variations in Pes (∆Pes) and Pdi (∆Pdi) relatived to initiation of effort.

  5. Inspiratory work

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    the pressure-time product of the respiratory muscles (PTPes/min) and of the diaphragm (PTPdi/min) were calculated under the Pes and Pdi versus time curve and expressed per minute.

  6. Sensation of breathing effort

    Time frame: 5 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O)

    Using questionnaire to assess the sensation of breathing effort. Sensation of breath effort of CPAP use was divided into three types corresponding to -1, 0, 1 score respectively, 0 refers to the same sensation as the feeling of breathing at the atmosphere without CPAP; 1 refers to the more difficult sensation to breath at the CPAP condition than at the atmosphere.; -1 refers to the easier sensation to breath at the CPAP condition than at the atmosphere.

Secondary outcomes

  1. Respiratory rate (RR)

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of respiratory rate (RR)

  2. Tidal volume (Vt)

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of tidal volume

  3. Minute ventilation (VE)

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of minute ventilation

  4. Peak inspiratory flow rate

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of peak inspiratory flow rate

  5. Expiratory muscle EMG

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    assessment of the electrical activity of the internal oblique muscle (EMG-obl) and the rectus muscle (EMG-rec)

  6. Expiratory pressure

    Time frame: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.

    The change in Pga resulting from the contraction of the abdominal muscles during expiration was analyzed

Sponsors and collaborators

Lead sponsor

State Key Laboratory of Respiratory Disease

Other

Registry information

Official study title

Effect of CPAP on Respiratory Load and Lung Volume in Stable COPD

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Apr 30, 2024
Registry last updated
Jul 10, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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