Effects of Face Masks on Oxygen Saturation and Functional Measures in Patients with Connective Tissue Disorder Associated Interstitial Lung Disease

Face masks are a first line defense against the COVID-19 pandemic. Many patients with lung disease complain of worsening dyspnoea on wearing face masks. Concerns about face masks reducing oxygen saturation have been negated by controlled studies in healthy individuals. In this study we have attempted to estimate the effects of face masks in patients with connective tissue disease (CTD) associated ILD (CTD-ILD). Patients with an established CTD, having HRCT (High Resolution Computed Tomography) findings of ILD and FVC(Forced Vital Capacity) of less than 70% on PFT with MRC grades 1 to 3 dyspnoea, and not requiring oxygen to maintain saturation, were included in this cross over trial. Initial oxygen saturation (SpO2) was recorded and a standard 6-minutes walk test (6MWT) was carried out with and without a standard 3-layer surgical face mask. All 36 patients completed 6 minutes of walking both with and without masks. When patients were in masks, they covered lesser distance and developed drop in saturation significantly more than while not wearing them. Without masks, 14 persons had a decline in SpO2 of 3% or more while, with masks, 19 persons had the same [p=0.3; Fisher exact test]. Thus, the use of face masks reduced the functional capacity and oxygen saturation during mild activity in patients with CTD-ILD. Through this study, it should be brought to the attention of ILD patients, their care-givers that the functional capacity is reduced with masks. The patients should limit physical exertion while wearing masks.