Characterizing particulate generation during cardiopulmonary rehabilitation classes with patients wearing procedural masks.

Helgeson, Scott A; Taylor, Bryan J; Lim, Kaiser G; Lee, Augustine S; Niven, Alexander S; Patel, Neal M

BACKGROUND The clinical benefits of cardiopulmonary rehabilitation are extensive, including improvements in health-related quality-of-life, emotional condition, physical function, and overall mortality. The coronavirus 2019 pandemic continues to negatively impact center-based cardiopulmonary rehabilitation. There is justifiable concern that the exercise-related increase in pulmonary ventilation within the rehabilitation classes may lead to the generation of infectious respiratory particles. RESEARCH QUESTION Is cardiopulmonary rehabilitation while wearing a procedural mask a particle generating procedure? STUDY DESIGN AND METHODS Data were collected prospectively at a cardiopulmonary rehabilitation facility with all patients wearing a procedural mask. Small (0.3-4.9μm) and large (5-10μm) particle generation was quantified using a light scattering particle counter. Data was analyzed by time, exertion level, and number of participants. RESULTS A total of 24 distinct patients attended ≥2 of the cardiopulmonary rehabilitation classes tested. The majority of the patients were male (n=16; 67%) and were in rehabilitation because of cardiac disease. During the cardiopulmonary rehabilitation class, small and large micron-sized particles increased with increasing class size. In classes with ≥4 patients, there was a significant increase from ambient levels in both small (4 patients; p<0.01 and 5 patients; p<0.01) and large (4 patients; p<0.01 and 5 patients; p<0.01) particle count that peaked at about 35-40 minutes during each class. INTERPRETATION Using an airborne particle counter, we found significant exercise related increases in both small and large micron-sized particle generation during cardiopulmonary rehabilitation classes, with larger class sizes (i.e. more patients), despite wearing a procedural mask.