Effect of CPAP on Respiratory Load in COPD

Not Applicable

Completed

• Conditions: Chronic Obstructive Pulmonary Disease
• Interventions: Device: Continuous Positive Airway Pressure

• Registration Number: NCT06390631
• Lead Sponsor: State Key Laboratory of Respiratory Disease

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Study First Submitted: 2024-04-25
• Study First Submitted QC: 2024-04-25
• Study First Posted: 2024-04-30
• Study Start: 2024-05-01
• Status Verified: 2024-07
• Primary Completion: 2024-07-01
• Last Update Submitted: 2024-07-08
• Study Completion: 2024-07-09
• Last Update Posted: 2024-07-10

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 19

Inclusion Criteria

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

Exclusion Criteria

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
CPAP treatment	Continuous Positive Airway Pressure	CPAP treatment in COPD patients

Primary Outcome Measures

Name	Time	Method
Inspiratory work	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.
Diaphragm EMG	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)
Sensation of breathing effort	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.
Lung volume	1-3 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O)	measurement of end inspiratory lung volume (EILV)
Inspiratory pressure	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.
Intrinsic positive end expiratory pressure (PEEPi)	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.

Secondary Outcome Measures

Name	Time	Method
Respiratory rate (RR)	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)
Tidal volume (Vt)	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
Peak inspiratory flow rate	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
Expiratory pressure	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
Minute ventilation (VE)	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
Expiratory muscle EMG	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)

Trial Locations

Locations (1)

Guangzhou Medical University; 🇨🇳 Guangzhou, Guangdong, China