Assessing the impact of different types of masks on COPD patients: a randomised controlled trial.

Background: Wearing masks imposes an additional respiratory burden on COPD patients. This study aimed to investigate the impact of various mask types on physiological parameters and subjective feelings in COPD patients. Methods: This randomised, open-label, parallel-controlled trial randomly assigned 129 COPD patients from two Chinese hospitals to the N95 mask group, the surgical mask group and the no mask group, who were required to complete a 6-min rest (6MR) and a 6-min walking test (6MWT) while wearing their designated masks, and were assessed for blood pressure, oxygen saturation, pulse rate, Borg score, rating of perceived exertion (RPE) score, 6-min walk distance (6MWD) and subjective feeling score. Data were analysed using intention-to-treat analysis and per-protocol analysis. Results: No significant differences were observed in blood pressure, oxygen saturation, pulse rate or the 6MWD among the three groups following a 6MR or 6MWT. Wearing N95 masks and surgical masks during the 6MWT significantly elevated perceived dyspnoea (p<0.001) and exertion scores (p<0.001) in COPD patients. The differences in the two scores between the highest and lowest groups were 2 and 4 points, respectively. Conclusion: Wearing surgical masks or N95 masks for 6MR or 6MWT did not adversely affect physiological parameters in COPD patients. However, it significantly increased perceived dyspnoea and exertion.