Evaluation of the pulmonary function of patients with severe coronavirus 2019 disease three months after diagnosis

There are few data regarding the repercussion in the pulmonary function of patients who had severe or critical COVID-19 pneumonia. The objective was to describe these patients' pulmonary function and establish an association with the severity of the disease (patients with severe or critical pneumonia), the presence of comorbidities, the tomographic involvement and the persistence of dyspnoea. Fifty-five patients were included, 40 (73%) male, media of age 54.9 (11.6) years old and body mass index (BMI) 33.1 (6.09) kg/ m2. Fifty (90%) had 1 comorbidity, obesity 67%, arterial hypertension 36%, and diabetes mellitus 35%. Twentyfive (45%) had critical pneumonia. Fifteen (27%) had a spirometric alteration that suggested restriction and 32 (58%) had gas exchange defect. The latter had forced volume capacity (FVC), forced expiratory volume in the first second (FEV1) and carbon monoxide diffusion capacity (DLCO) values significantly lower. Ninety percent presented some degree of involvement in the chest CT scan, ground glass-opacities the most frequent finding. A moderate negative correlation was found between the severity of the tomographic involvement and the DLCO levels. Thirty patients (55%) referred some degree of dyspnoea. Patients with this symptom had DLCO and KCO values below those who did not have dyspnoea: 70.5 vs. 85.1 p = 0.02 and 88 vs. 104 p = 0.02. The presence of abnormal gas exchange is the main characteristic of patients with pulmonary sequelae due to COVID-19. Our study does not show either predictor of evolution towards pulmonary sequelae or an association with the severity of the disease.