Effects of SARS-CoV-2 Infection on Pulmonary Function Tests and Exercise Tolerance

Abstract

<b>Introduction:</b> Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has showed to cause long-term pulmonary sequelae. <b>Objects:</b> The aim of this study was to evaluate the consequences on pulmonary function of the SARS-CoV-2 infection related to the severity of the disease and exercise tolerance. <b>Methods:</b> a retrospective cohort study was performed at the “Policlinico Tor Vergata” Academic hospital (Rome, Italy) where 75 patients evaluated in the post-COVID outpatient clinics at the Respiratory units were included in the study. Complete pulmonary function tests, 6-minute walk tests and persistence of symptoms were evaluated. <b>Results:</b> among the 75 subjects, 23 were mild, 16 moderate, 26 severe and 10 very severe based on the WHO classification. Very severe patients had a lower FVC (100±10%pr) compared to the others groups (116±16%pr, 116±13%pr, 122±20%pr from mild to severe; p&lt;0,05) and a lower TLC (94±13%pr) compared to the others (102±10%pr, 108±15%pr, 108±12%pr from mild to severe; p&lt;0,05). DL’co and DL’co/VA were similar among groups. At the 6MWT, distance, basal and nadir SpO2 were similar among groups, but all groups presented a significant decrease of SpO2 from basal to the nadir (Basal SpO2: 97,0±1,0% vs Nadir SpO2: 93,6±2,7%, p.&lt;0,01). A positive correlation was found between desaturation and delta SpO2 (basal – nadir) (R: 0.29, p&lt;0,05) and the Distance Desaturation Product (R: 0.39, p&lt;0,01). <b>Conclusions:</b> These results showed that, although the PFTs are within the normal range, there is a restrictive spirometric pattern in very severe subjects. Moreover, the only persistent pathological sequalae of SARS-CoV-2 infection were a mild desaturation at 6MWT, despite the severity.