ABSTRACT
Background: protective masks have emerged as a powerful mean to contain the COVID-19 pandemic. However, a general feeling that masks alter the normal dynamics of breathing may reduce the application of this protective device. Patients with heart failure (HF) experience dyspnea even during daily life activities (ADLs). Aim of the study is to evaluate cardiorespiratory parameters during ADLs, cardiopulmonary exercise test (CPET) and sleep to highlight any difference related to protective masks. Method(s): 9 healthy subjects (age 59+/-11, 2 female) and 10 HF patients (age 64+/-11, 2 female, ejection fraction <45%, stable conditions) underwent a set of cardiopulmonary tests twice, wearing a protective surgical mask and without it. We performed the following tests: standard spirometry;CPET;a set of tests recorded by a wearable ergospirometer (Cosmed K5), including ADLs (ADL1: getting dressed, ADL2: folding eight towels, ADL3: putting away 6 bottles, ADL4: making a bed, ADL5: sweeping the floor for 4 minutes, ADL6: climbing 1 flight of stairs carrying a load), six-minute walking test (6MWT) and two 4-minute treadmill exercises (TREAD2 and TREAD3 at a speed of 2 km/h and 3 km/h, respectively);home polysomnography (HPS). Result(s): Both healthy subjects and HF patients completed the protocol with no adverse events. Spirometry showed a reduction of forced expiratory volume in 1s (3.29+/-0.75 L vs 2.65+/-0.57 L as for healthy subjects, p= 0.002;2.45+/-0.6 L vs 1.97 +/-0.54 L as for HF patients, p= 0.002) and forced vital capacity (4.14+/-0.92 L vs 3.39+/-0.83 L as for healthy subjects, p= 0.004;2.93+/-0.76 L vs 2.59+/-0.73 L as for HF patients, p= 0.01) in both the groups from no mask to mask. As for the CPET, both healthy and HF patients showed: a trend of reduction of peak oxygen pulse (p<0.005 in healthy) and peak oxygen consumption (VO2);a decrease of tidal volume (Vt) at peak exercise (peak Vt: 2.283+/-0.449 L vs 1.864+/-0.359 L in healthy, p= 0.022;1.6+/-0.41 L vs 1.448+/-0.431 L in HF, p= 0.02), with no significative variations of resting and peak ventilation (VE). HF patients experienced a statistically significative decrease of VO2 at the anaerobic threshold (AT) (794+/-227 vs 682 +/-151 mL min-1, p=0.01). No significant differences in the other CPET parameters were observed. As for tests recorded by a wearable cart, task-related VO2 was significantly reduced from no mask to mask in ALDs and 6MWT in the healthy, whereas HF patients experienced a significative reduction in ADL1, ADL4, 6MWTand TREADs (probably more physically demanding tasks). Both healthy and HF subjects showed an increase in the basal and task-related ratio of VE vs carbon dioxide production (VE/VCO2) between the two protocol conditions. No difference in the main HPS parameters were observed from no mask to mask. Conclusion(s): Surgical masks slightly influences cardiorespiratory variables in healthy and HF patients at rest and during both mild and maximal physical activity. The physiological impact of the mask is far from being clinically relevant and no main differences between the groups were noted, except for an early AT in patients with HF. Since no main limitations were observed, the use of masks seems to be safe both in the general population and in HF patients. Moreover, it does not have a significant impact on sleep neither in healthy subjects nor in patients with HF, these ones particularly at risk of sleep apneas. These data should be confirmed in a larger group of patients.