Clinical trial NCT02655484: Carbon Dioxide Rebreathing During Exercise Assisted by Non-invasive Ventilation
Official title: Evaluation of Carbon Dioxide Rebreathing During Exercise Assisted by Non-invasive Ventilation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pulmonary Disease, Chronic Obstructive
Keywords: COPD
noninvasive ventilation
exercise
CO2 rebreathing
Lead sponsor: Guangzhou Institute of Respiratory Disease
Sponsor class: OTHER
First posted: 2016-01-14
Enrollment: 18
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP

Brief summary: The purpose of this study was to evaluate whether CO2 rebreathing occurs in healthy subjects or patients with COPD ventilated during exercise assisted by the single-limb circuit with a plateau exhalation valve at a given inspiratory positive airway pressure and a minimal level of expiratory positive airway pressure (EPAP) and whether there is a potential threshold for predicting CO2 rebreathing.

Detailed description: Non-invasive ventilation circuit consists of single-limb tubing for inspiration and expiration, including a plateau exhalation valve. As exhaled gases was vented out the plateau exhalation valve at a constant rate, during exercise, with the increase of exhalation flow, single-limb circuit with a plateau exhalation valve might cause carbon dioxide(CO2) rebreathing. Therefore, our aim in the present study was to evaluate whether CO2 rebreathing occurs in COPD patients ventilated during exercise assisted by the single-limb circuit with a plateau exhalation valve and estimate a potential threshold for predicting CO2 rebreathing.

Eligibility criteria: Inclusion Criteria:

* presented clinically stable (no exacerbation in the 4 weeks prior to study participation or with no change in medications);
* physician diagnosed COPD, forced expiratory volume in 1s (FEV1) \< 50% predicted;
* dyspnea as a main symptom that limited daily activities.

Exclusion Criteria:

* subjects with obvious pulmonary bullae demonstrated by chest CT scan or X-ray;
* examination or facial trauma/malformation, recent facial, upper airway or upper gastrointestinal tract surgery, that would preclude receiving NIV therapy;
* a history of coronary artery disease or cardiac arrhythmias or potential electrocardiographic alterations;
* a history of uncontrolled hypertension, or other respiratory diseases;
* oxygen saturation(SpO2) \< 88% at rest with a fraction of inspired oxygen (FiO2) ≥ 0.5;
* patients with musculoskeletal or neurological disorders;
* or failure to comply with the research protocol.

Primary outcomes:
measure: mean exhalation valve flow
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
Secondary outcomes:
measure: mean exhalation flow
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: mean inspiratory fraction of CO2 for each tidal volume
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: fraction of end-tidal carbon dioxide partial pressure
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: inspiratory time
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: expiratory time
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: respiratory rate
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: inspiratory tidal volume
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
measure: expiratory tidal volume
timeFrame: Measurements were collected continuously throughout a symptom-limited cycle exercise test （test lasts for about 8-12 min） while subjects breathed through the full face mask. Analyses were made breath by breath during the whole test process.
Other outcomes:
Locations:
city: Guangzhou
country: China
facility: State Key Laboratory of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University
state: Guangdong
Study officials:
affiliation: Guangzhou Institute of Respiratory Disease
name: Rongchang Chen, MD
role: PRINCIPAL_INVESTIGATOR
References: