Post-COVID Pulmonary Function Test Evaluation

Since the lung is the most affected organ by COVID-19 disease, we aimed to evaluate the pulmonary function test, presence of hypoxemia, and Post-COVID-19 Functional Status Scale in 3- to 6-month post-COVID period.

Post-COVID-19 Functional Status Scale, pulse oxygen saturation, and pulmonary function test were evaluated in 67 outpatients/inpatients after 3-6 months following COVID-19 (positive reverse transcription-polymerase chain reaction on nasopharyngeal swab) disease. Pre-COVID pulmonary function test parameters were available in 33 patients, and these were compared with post-COVID pulmonary function test parameters.

We found 20.9% (14 patients) restrictive and 11.9% (8 patients) obstructive patterns in pulmonary function test. Of those with forced vital capacity < 80%, 53.3% were patients without known lung diseases. When pulmonary function test values before and after COVID-19 were compared, only a loss of 130 mL in forced expiratory volume in 1 second was determined (P = .005). About 65.4% of the patients with dyspnea were in the group without a lung disease (P = .002) and 66.7% of patients with forced expiratory volume in 1 second and forced vital capacity of .05). Smoking, hospitalization, oxygen support, and the severity of computed tomography involvement did not impact pulmonary function test.

In post-COVID patients, the major disorder in the respiratory function test was determined as a restriction. However, advanced tests such as lung volumes and carbon monoxide diffusing capacity (DLCO) measurement and high-resolution lung tomography are needed to differentiate in terms of physical functional limitation or parenchymal fibrosis.