Prospective analysis of the physiological changes caused by prolonged use of N95-type masks.

Introduction: The clinical and physiological effects of long-duration use of N95-type masks without ventilation valves, on health-care workers during the coronavirus disease-2019 (COVID-19) pandemic, were evaluated.

Methods: All volunteering personnel working in operating theater or intensive care unit, using nonventilated N95 type respiratory masks, minimum for a 2-h noninterrupted duration were observed. The partial oxygen saturation (SpO₂) and heart rate (HR) were recorded before wearing the N95 mask and at 1^st and 2^nd h. Volunteers were then questioned for any symptoms.

Results: A total of 210 measurements were completed in 42 (24 males and 18 females) eligible volunteers, each having 5 measurements, on different days. The median age was 32.7. Premask, 1^st h, and 2^nd h median values for SpO₂ were 99%, 97%, and 96%, respectively (P < 0.001). The median HR was 75 premask, 79 at 1^st h, and 84/min at 2^nd h (P < 0.001). A significant difference between all three consecutive measurements of HR was achieved. Statistical difference was only reached between premask and other SpO₂ measurements (1^st and 2^nd h). Complaints seen in the group were head ache (36%), shortness of breath (27%), palpitation (18%), and nausea feeling (2%). Two individuals took off their masks to breathe, on 87^th and 105^th min, respectively.

Conclusions: Long duration (>1 h) use of N95-type masks causes a significant reduction in SpO₂ measurements and increase in HR. Despite being an essential personal protective equipment in COVID-19 pandemic, it should be used with short intermittent time periods in health-care providers with known heart disease, pulmonary insufficiency, or psychiatric disorders.