Gas Mask and Chronic Obstructive Pulmonary Disease (COPD): New Understanding on the Respiratory Index Impact?
Gas Mask and Chronic Obstructive Pulmonary Disease (COPD): New Understanding on the Respiratory Index Impact?
Background: The gas mask is used to protect the aiways against respiratory hazards (CBRN
 agents). Within the CBRNE committee, speculations are that unprotected lungs would look like
 to those of COPD patients in post-exposure of some CBRNE 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 9 COPD patients to evaluate breathing
 patterns, index of respiratory efforts and blood gases. Three conditions have been tested in
 a randomized order: 1x baseline and 2x different canisters, with and without a mask (C4,
 Airboss Defence, Bromont, Canada). Airway pressure, inspiratory and expiratory flows have
 been measured. An esophageal catheter is introduced at the beginning of the study to measure
 esophageal pressure (Peso) and calculate indexes of respiratory effort (PTPeso, WOB). SpO2 is
 continuously measured and capillary blood bases are drawn at the end of each condition. Each
 condition lasts 10 minutes, data of the last 2 minutes at a steady state are considered for
 analyses. Results. We are compiling data and processing them for analysis.
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). While few
 studies have been about the gas mask technology, no-study addresses it in regards of the
 impact from a bad airway protection and consequences on the respiratory system.

 The gas mask design and its components may lead to these respiratory load issues. At rest and
 from different resistances, 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 on a: i. 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. Our goal is to measure the impact of the work of breathing and
 the gas exchange for a gas mask user and also a COPD patient. We also measure what was the
 optimal means for correcting the hypoxemia with a subject.

 9 COPD patients have been participating in a comparison and single-blind randomized
 experimental study. That was approved by the Ethical Review Committee. A written consent is
 obtained for all the subjects prior their acceptance. No rejection has happened during the
 recruiting so far. The eligibility criteria are: i. COPD diagnosis from mild-to-severe FEV
 30-80%). The exclusion criteria are: i. Refusals relate to wear the oesophageal catheter and
 for capillary punctures; ii. Claustrophobia; iii. Oesophageal wounds backgrounds; iv. No
 coronary background and stroke history; v. No face morphology incompatibility with the mask.
 Spirometry and usual health screening is also done before starting the clinical trial.

 Design comprises three 10-minute testing conditions split in two parts. All has been at rest
 and sitting on a chair: i. Baseline without gas mask; ii. Gas mask and Canister A; iii. Gas
 Mask and Canister B. Between the condition a 5-minute wash-out takes place.

 Three five-minute periods is followed to record blood pressure and pulse during the
 conditions. SpO2 is continuously measured with Free O2. Capillary punctures are done at the
 end of each condition. Comfort was also assessed.

 Our main measurements are the WOB performed with a continuous recording of Peso pressure and
 respiratory volumes. Software Acknowledge, version 3.9 serves as acquisition data system and
 analysis are achieved with a 4.2 version and a free-trial WOB calculus system, named RESPMAT.
 That is obtained from Maynaud and al.(2014). As power source, we use a BIOPAC (MP100, Santa
 Barbara, Californie, USA, 200 Hertz), four differential sensors (Validyne : 1x MP45±100
 cmH2O; 2x MP100±5 cmH2O; 1x MP100±100 cmH2O) and four Carrier D-Modulators (Validyne,
 CT-15,120 Volt, 60 Hertz, 5Watts, Model CD15-A-2-A-1).

 Single esophageal catheter (Type Cooper, French caliber #5) and disposable pneumotachs are
 used. Lidocain spray and K-Y gel are applied during the insertion of the catheter. Its
 placement is done at 37.6±5.7 cm across the subject and a Mueller test is performed for each
 subject. In regard of spontaneous breathing, an Hudson mask is used while a C-4 Gas Mask with
 a canister was employed (Manufacturer: Airboss Defence, Bromont, Canada). Canister A and B
 were respectively a C7A1 and ADB81 trademark. Prototyped Free O2 System is employed for the
 correction of the hypoxemia.
Inclusion Criteria:

 • COPD Diagnosis: mild-to-moderate, with FEV1 30-80% and requiring no long-term
 oxygenotherapy.

 Exclusion Criteria:

 -  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.