Clinical Trial: The Gas Mask: the Effects on Respiration!

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Impact of Gas Masks on Index of Efforts and Breathing Pattern

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 an

Detailed Summary:

The principal way of penetration of CBRNE agents is the respiratory system. The current technology of a gas mask has been used to protect the respiratory system as far back as the First World War. That originated from Dr Cluny Macpherson's initiatives whom was a Canadian military physician.

The military gas mask is part of the respirator classification but owes its specific features. Conventionally, the military gas mask covers a large spectrum of protection aspects and matched with their specific canisters. Consequently, gas masks are usually studied separately from other respirators and Self-Contained Breathing Apparatus (SBCA).

The gas mask design and its components may lead to these respiratory load issues. At rest and effort, what would be the impacts for the work of breathing and gas exchange? In order to avoid hypoxemia and hyperoxia, what would be the optimal means to restore proper oxygenation? We hypothesised: i. on a heightened WOB and the respiratory demands related to wear of the gas mask; ii. An occurrence of hypoxemia will be manifesting during a continuous period at both at rest and effort.

Our goal was to measure the impact of the work of breathing and the gas exchange for a gas mask user. We also measured what was the optimal means for correcting the hypoxemia with a subject.

14 Male Human Subjects participated in a comparison and single-blind randomized experimental study. That was approved by the Ethical Review Committee. All male subjects were in averaged age of 38.9±5 year old and a FEV1 4.60±0.70 Liter. A written consent was obtained for all the subjects prior their acceptance. No rejection happened during the recruiting. The eligibility criteria were: i. No significant cardiac and respirator
Sponsor: Laval University

Current Primary Outcome: indexes of respiratory effort [ Time Frame: 10 minutes ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: Laval University

Dates:
Date Received: May 19, 2016
Date Started: June 2015
Date Completion:
Last Updated: September 27, 2016
Last Verified: September 2016