Zhongguo quanke yixue (Aug 2023)
Cardiopulmonary Physiology Effects of Wearing a Surgical Mask Versus an N95 Respirator in Patients with COPD during Walking: a Randomized Crossover Controlled Trial
Abstract
Background During the COVID-19 pandemic, wearing masks and maintaining social distancing have become common personal protective measures. However, there is little research on alterations in cardiopulmonary function of patients with chronic obstructive pulmonary disease (COPD) after wearing different masks. Objective To study the effect of wearing a surgical mask versus an N95 respirator on cardiopulmonary function in patients with COPD. Methods Thirty patients diagnosed with COPD in General Hospital of Xinjiang Military Region were recruited from 30th June to 10th August, 2022, and randomly assigned to either an N95 respirator group (n=15) or a surgical mask group (n=15) . Both groups underwent two bouts of walking on a treadmill at a speed of 4 km/h for 20 min with an interval of 24 h (washout period) , with the difference that N95 respirator group wore an N95 respirator in the first bout and a surgical mask in the second bout, and surgical mask group did the opposite. Arterial blood gas analysis was performed, and heart rate, blood pressure and respiratory rate were measured immediately after each bout of walking, and the overall pre- and post-experiment alterations of these indicators were calculated. The lowest percutaneous arterial oxygen saturation (SpO2) and the maximum respiration rate during the experiment were monitored, and adverse events were recorded as well. Results All the participants completed the experiment. Compared with the surgical mask group, N95 respirator group had increased difference between pre- and post-experiment arterial pH〔0.013 (0.020) vs -0.004 (0.010) , P=0.001〕, arterial partial pressure of carbon dioxide (PaCO2) 〔1.2 (1.2) mmHg vs 0.5 (1.6) mmHg, P=0.001〕 or arterial partial pressure of oxygen (PaO2) 〔12.5 (10.5) mmHg vs 5.0 (13.2) mmHg, P=0.002〕. In the experiment, dyspnea occurred in 25 cases (83.3%) wearing an N95 respirator, and 16 cases (53.3%) wearing a surgical mask. Compared with wearing a surgical mask, the relative risk of dyspnea in COPD patients wearing an N95 respirator during the experiment was 1.563〔95%CI (1.078, 2.264) , P=0.012〕. Conclusion COPD patients wearing an N95 respirator during walking are more likely to have alterations in arterial pH, PaCO2 and PaO2 levels, which affect the gas exchange and may cause dyspnea.
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