Protective face masks add significant dead space

Abstract

Lately, protective face masks have become part of everyday life and many patients and healthcare workers complain of reduced well-being and performance due to the permanent wearing of such masks. Reportedly, the main symptoms are headaches and difficult breathing, especially in combination with stress and physical exertion [1–3]. It is suspected that protective masks impede oxygen supply to the lungs and increase carbon dioxide rebreathing [4]. Theoretical estimations suggest that indeed the dead space increases for mask wearers [5] and this would translate into increased arterial CO2 levels with concomitant increase in work of breathing through control-of-breathing mechanisms. Added flow resistance of protective face masks, as well as comfort and general physiological effects, have been described in the literature [6–8]. However, the effect on gas exchange is poorly investigated, basically because standard procedures involve using a mouthpiece and a nose clip, or a dedicated face mask (European Respiratory Society recommendation [9]), which is obviously not possible in subjects wearing a protective face mask. To investigate this question, the use of a lung simulator seemed to be an obvious approach. Protective face masks significantly increase dead space ventilation. Rebreathing of carbon dioxide through the added dead space may create discomfort and perceived increase of work of breathing. https://bit.ly/32QRme3