Impact of Gas Masks on Index of Efforts and Breathing Pattern
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 15
- 试验地点
- 2
- 主要终点
- indexes of respiratory effort
研究概览
简要总结
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.
详细描述
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 respiratory diseases known; ii. No epilepsy background; iii. No severe pathology requiring medication; iv. No pregnancy for woman; v. Face medium - size in relation of the gas mask. The exclusion criteria were: 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 was also done before starting the clinical trial.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Health Services Research
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- 未提供
排除标准
- 未提供
结局指标
主要结局
indexes of respiratory effort
时间窗: 10 minutes
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.
次要结局
未报告次要终点
研究者
François Lellouche
Physician
Laval University