Increased airway hyperreactivity with the M40 protective mask in exercise-induced bronchospasm

Impact of wearing a surgical mask on respiratory function in view of a widespread use during COVID-19 outbreak. A case-series study

BACKGROUND

Because of the COVID-19 outbreak, the widespread use of Respiratory Protective Devices (RPD) is recommended to prevent the spread of infection. This recommendation involves not only healthcare workers but other category of workers and the general population as well, in public places, especially where social distancing is difficult to maintain. The use of facemasks should not cause physical impairment to individuals, especially for people suffering from lung and heart diseases.

OBJECTIVES

To evaluate the impact of RPDs on the respiratory function in healthy and asthmatic subjects, in order to identify the fitness for use mainly, but not only for, occupational purposes during COVID-19 outbreak.

METHODS

Ten individuals were included, three of which affected by asthma and three current smokers. A Respiratory Functional Test (RFT) was performed at three times: at the beginning of the work shift 1) without wearing and 2) wearing surgical masks, and 3) after 4 hours of usual working activities wearing the masks. Arterial Blood Gas (ABG) samples were also tested before the first test and the third test.

RESULTS

Observed RFTs and ABG parameters did not suffer significant variations, but for Maximal Voluntary Ventilation (P=0.002). Data on asthmatic subjects and smokers were comparable to healthy subjects.

DISCUSSION

Our results suggest that wearing a surgical mask does not produce significant respiratory impairment in healthy subjects nor in subjects with asthma. Four hours of continuing mask-wearing do not cause a reduction in breathing parameters. Fitness for use in subjects with more severe conditions has to be evaluated individually. Our adapted technique for RFTs could be adopted for the individual RPDs fitness evaluation.

Evaluation of fitness to utilize Self-Contained Breathing Apparatus (SCBA)

BACKGROUND

Breathing dry, cold air may cause bronchoconstriction in asthmatics working with self-contained breathing apparatus (SCBA). Air delivered by SCBA is cooler than ambient air. It is unclear whether a bronchial challenge test using mannitol (BCTM) can predict a fall in forced expiratory volume in one second (FEV(1)) during exercise with SCBA.

METHODS

A prospective study of army recruits assigned to work with SCBA was carried out. Participants completed self-administered questionnaires on respiratory symptoms, BCTM, and measurement of exhaled nitric oxide. A subgroup of participants with a positive BCTM (BTCM+) and with negative BCTM underwent exercise test on bicycle ergometer (ET) while using SCBA.

RESULTS

One hundred and six recruits participated in this study. One hundred and two underwent BCTM and 28 ET. Nineteen out of 97 participants had a positive BCTM and 6 out of 27 had a positive ET. Seventeen out of 19 participants with a positive BCTM had current respiratory symptoms such as wheeze, cough, chest tightness, or dyspnea. Sensitivity, specificity, positive predictive value, and negative predictive value for a positive ET under SCBA were 100%, 64%, 43%, and 100% for the BCTM, respectively. BCTM-positive participants with respiratory symptoms had more physician consultations during MBT compared to BCTM-negative participants.

CONCLUSION

Despite medical evaluation and exclusion of asthmatics by a physician during conscription, a high proportion of recruits assigned to work with SCBA smoke, have respiratory symptoms, and have a positive BCTM suggesting current asthma. BCTM has a high sensitivity to predict a significant fall in FEV(1) after exercise with SCBA and participants with a positive BCTM tend to use more health care resources during basic military training. Recruits should be counseled about smoking cessation prior and during basic military training.