Evaluation of CO2 Rebreathing During Exercise With the Increasing Ventilation Assisted by NIV With a Dual-limb Circuit

Evaluation of Carbon-dioxide Rebreathing During Exercise With the Increasing Ventilation Assisted by Noninvasive Ventilation With a Dual-limb Circuit

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).

Study Overview

• Status: Completed
• Conditions: Chronic Obstructive Pulmonary Disease
• Intervention / Treatment: Device: dual-limb NIV

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.

• Study Type: Interventional
• Enrollment (Actual): 8
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510000
      • The First Affiliated Hospital of Guangzhou Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: dual-limb NIV; A maximal cycle exercise test with the participants assisted by BiPAP (Servo i, Maquet, Siemens) receiving 10 cmH2O pressure support in addition to oxygen therapy. During the test, breathing pattern, inspiratory flow of the inhalation limb and expiratory flow of the exhalation limb, fractional concentration of inspired CO2 (FiCO2) of the inspiratory line was measured for each breath were recorded.

Device: dual-limb NIV; dual-limb NIV was served with servo i ventilator

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fractional concentration of inspired CO2	FiCO2	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 Outcome Measures

Outcome Measure	Measure Description	Time Frame
inspiratory flow of the inhalation limb	Vti/Ti	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.
expiratory flow of the exhalation limb	Vte/Te	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.
breathing pattern	Ti、Te、Ti/Ttot、RR	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.

Collaborators and Investigators

• Sponsor: Guangzhou Institute of Respiratory Disease
• Investigators: Study Director: Rongchang Chen, The First Affiliated Hospital of Guangzhou Medical University

Study record dates

Study Major Dates

• Study Start (Actual): June 23, 2018
• Primary Completion (Actual): February 3, 2019
• Study Completion (Actual): March 31, 2019

Study Registration Dates

• First Submitted: May 30, 2018
• First Submitted That Met QC Criteria: May 30, 2018
• First Posted (Actual): June 13, 2018

Study Record Updates

• Last Update Posted (Actual): July 30, 2019
• Last Update Submitted That Met QC Criteria: July 29, 2019
• Last Verified: June 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
• Other Study ID Numbers: GIRD201802

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No