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.

最近，防护口罩已成为日常生活的一部分，许多患者和医护人员抱怨由于长期佩戴此类口罩而导致健康和工作表现下降。据报道，主要症状是头痛和呼吸困难，尤其是伴有压力和体力消耗 [1-3]。有人怀疑防护面罩会阻碍肺部的氧气供应并增加二氧化碳的再呼吸 [4]。理论估计表明，面罩佩戴者的死腔确实增加 [5]，这将转化为增加的动脉 CO ₂通过控制呼吸机制，伴随着呼吸功的增加。防护面罩增加的流动阻力以及舒适度和一般生理效应已在文献 [6-8] 中有所描述。然而，对气体交换的影响却鲜有研究，主要是因为标准程序涉及使用咬嘴和鼻夹，或专用面罩（欧洲呼吸学会建议 [9]），这在佩戴防护面罩的受试者中显然是不可能的面具。为了研究这个问题，使用肺模拟器似乎是一种显而易见的方法。