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 (SpO) and heart rate (HR) were recorded before wearing the N95 mask and at 1 and 2 h.