The Gas Mask: the Effects on Respiration!

NCT02782936 | Completed

• 2 other identifiers: 211402015-2448
• Study Type: interventional
• Target: 15
• Locations: 1 country
• Sites: 1

Brief Summary

Background: The gas mask is used to protect military and non-military subjects exposed to respiratory hazards (CBRN agents). The aim of the study was to evaluate the impact of the gas mask on respiratory patterns and indexes of the respiratory effort. Methods: We are completing our study with 14 healthy subjects to evaluate breathing patterns, index of respiratory efforts and blood gases. Seven conditions have been tested in a randomized order: at rest, during effort (on a tread mill, standardized at 7 METs for all subjects) and during induced hypoxemia with and without a mask (C4, Airboss Defence, Bromont, Canada). Airway pressure, inspiratory and expiratory flows were measured. An esophageal catheter was introduced at the beginning of the study to measure esophageal pressure (Peso) and calculate indexes of respiratory effort (PTPeso, WOB). SpO2 was continuously measured and capillary blood bases were drawn at the end of each condition. Each condition lasted 10 minutes, data of the last 2 minutes at a steady state were considered for analyses. Results: The preliminary analyses based on 10 subjects are presented here. Comparing the wearing of the gas mask and without, most of the respiratory index increased in the tested conditions (at rest, during induced hypoxemia and during effort). At rest, in 8 out of 10 healthy subject the indexes of effort were higher with the gas mask, a statistical trend was observed with the WOB (0.22±0.13 vs. 0.28±0.10 J/cycle; p = 0.059), the PTPes (101±35 vs. 122±47 cmH2O\*s; p=0.21) and SwingPeso (4.4±2.0 vs. 5.3±2.0 cmH2O; p=0.13). During the effort, the respiratory index increased (WOB 4.0±2.6 vs. 5.6±3.2; p=0.10; PTPeso 406±211 vs. 606±65; p=0.04; SwingPeso 14.8±8.1 vs. 21.8±9.0; p=0.13). There was no difference for the breathing pattern and arterial blood gases data with and without mask. Data for induced hypoxemia are under analysis. We measured on bench the inspiratory and expiratory resistances of the tested gas mask (C4: inspiratory resistances = 3.2 cmH2O at 1 L/sec; expiratory resistances = 0.9 cmH2O at 1 L/sec). This may explain in part the increased work of breathing with masks. Conclusions: This study demonstrated an increase of the indexes of respiratory effort during an exercise with the gas mask. This study is the first to directly assess the indexes of efforts with esophageal pressure in this situation. Our results and method may be used as a reference for evaluating tolerance with different designs of gas masks.

Conditions

Work of Breathing

Keywords

Work of Breathing; Hypoxemia; Respiratory Acidosis; Respiratory effort

Outcome Measures

Primary Outcomes (1)

• indexes of respiratory effort

  In this study, we speculate the work of breathing is increasing with the use of a gas mask at rest, under hypoxemia condition and during physical effort.

  10 minutes

Study Arms (3)

Baseline

EXPERIMENTAL

Randomised baseline without and with gas mask.

Other: measurement of the work of breathing; Device: Gas mask

Induced Hypoxemia

EXPERIMENTAL

Randomised hypoxemia: i. without gas mask; ii. with gas mask; and iii. correction with FreeO2 and gas mask.

Other: measurement of the work of breathing; Device: Gas mask

Effort

EXPERIMENTAL

Randomised effort without and with gas mask

Other: measurement of the work of breathing; Device: Gas mask

Interventions

measurement of the work of breathing OTHER

We have been evaluating breathing patterns, index of respiratory efforts and blood gases in all randomized conditions. A gas mask has been used mask (C4, Airboss Defence, Bromont, Canada). Airway pressure, inspiratory and expiratory flows have been measured. An esophageal catheter has been introduced at the beginning of the study to measure esophageal pressure (Peso) and calculate indexes of respiratory effort (PTPeso, WOB). SpO2 has been continuously measured and capillary blood bases were drawn at the end of each condition. Each condition lasted 10 minutes, data of the last 2 minutes at a steady state has been considered for analyses.

Baseline; Effort; Induced Hypoxemia

Gas mask DEVICE

During the conditions that involved a gas mask, the measurement of the work of breathing is achieved with a oesophageal catheter and two disposable pneumotachs. While the oesophageal catheter has been fixed to the mandibular with an hypo-allergic tape, the two pneumotachs are hooked respectively on the canister and exhalation port of the gas mask. Investigators have induced the hypoxemia with a mixture nitreous and medical gas in a plastic bag that has been setted up to the canister. The FiO2 level has been kept to 14 percent.

Also known as: Canadian Gas Mask C-4 manufactured by Airboss Defence, Bromont, Québec, Canada.

Baseline; Effort; Induced Hypoxemia

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Having no significant cardiac and respiratory pathology
• Having no history of epilepsy
• Having no severe and chronic pathology that requires medication
• Not being pregnant
• Face size: medium

You may not qualify if:

• Refuse to participate in the study for one of the following reasons: i. wearing a oesophageal catheter; ii. wearing the gas mask; iii. giving blood sample; iv. claustrophobia.
• Oesophageal background wounds
• Facial anthropometrical issues.

Sponsors & Collaborators

• Laval University: lead
• Pierre-Alexandre Bouchard, RT.: collaborator
• Captain (Ret) Stephane Bourassa, RN.: collaborator

Study Sites (1)

Institut de recheche universitaire de cardiologie et pneumologie de Québec

Québec, Quebec, G1V4G5, Canada

Location

Related Publications (2)

• Bourassa S, Bouchard PA, Dauphin M, Lellouche F. Oxygen Conservation Methods With Automated Titration. Respir Care. 2020 Oct;65(10):1433-1442. doi: 10.4187/respcare.07240. Epub 2020 Feb 18.

  PMID: 32071135 DERIVED

• Bourassa S, Bouchard PA, Lellouche F. Impact of Gas Masks on Work of Breathing, Breathing Patterns, and Gas Exchange in Healthy Subjects. Respir Care. 2018 Nov;63(11):1350-1359. doi: 10.4187/respcare.06027. Epub 2018 Jul 31.

  PMID: 30065082 DERIVED

MeSH Terms

Conditions

Hypoxia; Acidosis, Respiratory

Interventions

Respiratory Protective Devices

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Respiratory Insufficiency; Respiration Disorders; Respiratory Tract Diseases; Acidosis; Acid-Base Imbalance; Metabolic Diseases; Nutritional and Metabolic Diseases

Intervention Hierarchy (Ancestors)

Personal Protective Equipment; Protective Devices; Equipment and Supplies; Manufactured Materials; Technology, Industry, and Agriculture

Study Officials

• Francois Lellouche, Doctorate

  Institut de Recherche Universitaire de Cardiologie et Pneumologie de Québec

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Physician

Study Record Dates

• First Submitted: May 19, 2016
• First Posted: May 26, 2016
• Study Start: June 1, 2015
• Primary Completion: July 1, 2016
• Study Completion: July 1, 2016
• Last Updated: September 29, 2016

Record last verified: 2016-09

Locations

CA (1)