Carbon Dioxide Rebreathing During Exercise Assisted by Non-invasive Ventilation

Evaluation of Carbon Dioxide Rebreathing During Exercise Assisted by Non-invasive Ventilation

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.

Study Overview

• Status: Completed
• Conditions: Pulmonary Disease, Chronic Obstructive
• Intervention / Treatment: Device: BiPAP® Vision® ventilator（"Ventilator", "Philips Respironics™ BiPAP® Vision®" ）

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.

• Study Type: Interventional
• Enrollment (Actual): 18
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China, 510120
      • State Key Laboratory of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• 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;
• 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.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: COPD patients; Oxygen was delivered to the face mask by a tube at a constant rate (5L/min) to keep the fingertip oxygen saturation at 90% or above. Ventilatory assistance was delivered using a BiPAP® Vision® ventilator (Respironics, Murrysville, Pennsylvania, USA) in BiPAP mode applied via a tightly fitting full face mask (Curative, Suzhou, China). A symptom-limited cycle exercise test was performed while assisted by non-invasive ventilation (NIV). All measurements were recorded at inspiratory pressure of 14 cmH2O, expiratory pressure of 4 cmH2O during rest and exercise. Breathing pattern, mean exhalation flow, mean plateau exhalation valve flow, the mean inspiratory fraction of CO2 (tidal FiCO2) reinsufflated from the circuit between the mask and the exhalation valve was measured for each breath.

Device: BiPAP® Vision® ventilator（"Ventilator", "Philips Respironics™ BiPAP® Vision®" ）; See details from arm descriptions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
mean exhalation valve flow	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	Time Frame
mean exhalation flow	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.
mean inspiratory fraction of CO2 for each tidal volume	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.
fraction of end-tidal carbon dioxide partial pressure	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.
inspiratory time	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 time	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.
respiratory rate	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.
inspiratory tidal volume	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 tidal volume	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: Principal Investigator: Rongchang Chen, MD, Guangzhou Institute of Respiratory Disease

Study record dates

Study Major Dates

• Study Start: January 1, 2016
• Primary Completion (Actual): May 1, 2016
• Study Completion (Actual): May 1, 2016

Study Registration Dates

• First Submitted: January 6, 2016
• First Submitted That Met QC Criteria: January 13, 2016
• First Posted (Estimate): January 14, 2016

Study Record Updates

• Last Update Posted (Estimate): July 18, 2016
• Last Update Submitted That Met QC Criteria: July 15, 2016
• Last Verified: July 1, 2016

More Information

Terms related to this study

• Keywords: exercise; COPD; noninvasive ventilation; CO2 rebreathing
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Lung Diseases, Obstructive; Pulmonary Disease, Chronic Obstructive
• Other Study ID Numbers: 2009CB522112