Chronic Obstructive Pulmonary Disease
Conditions
Brief summary
Ventilated by a single-limb tubing with PEV caused CO2 rebreathing to COPD patients during exercise with the increasing ventilation. The aim of this study was to evaluate whether CO2 rebreathing could be avoided with the use of the dual-limb circuit, to provide a theoretical basis of more rational clinical application of NIV in the setting of increasing ventilation(eg, after exercise).
Detailed description
Exercise training is a key component of pulmonary rehabilitation. It has shown signifcant improvements in both exercise tolerance and quality of life in patients with COPD. The intensity of exercise training is of great importance to yield a true physiologic effect. However, in patients with severe COPD, exertional dyspnea and leg fatigue make it impossible for the patient to maintain intensity of training for enough time to achieve a physiologic training effect. NIV has been reported to be used as support for exercise to improve exercise tolerance and respiratory performances in patients with mild-to-severe COPD with inconsistent results. Evidence from previous studies have suggested that NIV with a single-limb circuit with Whisper Swivel II expiratory valve or Plateau exhalation valve assisted during exercise in patients with COPD caused CO2 rebreathing. CO2 rebreathing may have a negative impact on efficacy. Previous studies have proved that exercise tolerance was improved ventilated by NIV with a dual-limb circuit. In theory, NIV with a dual-limb circuit consists of one inhalation limb that introduces air into the patient's airways and one exhalation limb that leads exhaled gas outside of the airways, there is no risk of rebreathing. However, there was no report on whether there's no risk of rebreathing in COPD patients ventilated during exercise by a dual-limb circuit. Therefore, the aim of the study was to determine whether there was no CO2 rebreathing occurred assisted with NIV with dual-limb circuit in patients with stable severe COPD after exercise with exertional dyspnea.
Interventions
DEVICEdual-limb NIV
dual-limb NIV was served with servo i ventilator
Sponsors
Guangzhou Institute of Respiratory Disease
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
40 Years to 80 Years
Healthy volunteers
No
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; * patients with musculoskeletal or neurological disorders; * failure to comply with the research protocol.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| fractional concentration of inspired CO2 | 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. | FiCO2 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| inspiratory flow of the inhalation limb | 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. | Vti/Ti |
| expiratory flow of the exhalation limb | 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. | Vte/Te |
| breathing pattern | 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. | Ti、Te、Ti/Ttot、RR |
Countries
China
Outcome results
None listed