Evaluation of the Pulmonary Function Test (PFT) in Patients Affected by Severe COVID-19 Pneumonia: 6 to 12 Weeks After Discharge

Abstract

The most lethal adverse effect of COVID-19 is acute respiratory distress syndrome, which can lead to rapid death. This symptom even causes concern for patients who have recovered and have been discharged. Therefore, it is obligatory to test and monitor variations in their lungs’ function after recovery. In this study, we evaluated the pulmonary function of 64 patients with severe COVID-19, six weeks to 3 months after discharge. Pulmonary function parameters were measured by spirometry and body box according to the criteria of the American Thoracic Society and under the supervision of an adult pulmonologist. According to the forced expiratory volume (FEV1)/forced vital capacity (FVC) ratio and total lung capacity (TLC) values, it was found that 3.1% of people had an obstructive pattern, 40.63% of patients had the restrictive pattern, and 6.25% of improved individuals showed a mixed pattern. Furthermore, the study of diffusion capacity of carbon monoxide (DLCO) index revealed that 13.3%, 25%, and 53% of cases had mild, moderate, and severe disorders of gas exchange, respectively. In addition, determining the maximum amount of inspiratory muscles (PI max) and expiratory muscles (PE max) disclosed that the rate of these two indicators in 62.5% and 71.88% of the subjects were less than 50%, respectively. In general, the results of the present study suggest that pulmonary function test and follow-up of patients' condition are not only recommended but seems to be essential after recovery due to the large percentage of patients with the restricted pattern a few weeks after recovery.

The Assessment of Functional Status Among COVID-19 Patients at Three Months Using Pulmonary Function Tests

“…Babadi et al's study on severe COVID-19 pneumonia patients found 3.1% with an obstructive pattern, 40.63% with a restrictive pattern, and 6.25% with a mixed pattern. These findings underscore the diverse pulmonary function outcomes in individuals recovering from severe COVID-19 [ 16 ].…”

“…The use of non-invasive and inexpensive procedures such as PFT, which includes FEV1, FVC, FEV1/FVC ratio, and the six-minute walk test, has proven valuable in identifying residual lung disease in individuals post lung infections, including COVID-19. Several studies, including those by Truffaut et al [ 14 ], Zhao et al [ 15 ], and Babadi et al [ 16 ], have demonstrated the persistent impact on lung function and other parameters in post-COVID-19 patients.…”