Pulmonary function of patients with 2019 novel coronavirus induced-pneumonia: a retrospective cohort study

The aim of this study was to investigate the pulmonary function of patients with 2019 novel coronavirus (COVID-19)-induced pneumonia.

A retrospective analysis of 137 patients with COVID-19-induced pneumonia who were discharged from the Enze Hospital, Taizhou Enze Medical Center (Group) from January 31 2020 to March 11 2020 was conducted. Follow-up occurred 2 weeks after hospital discharge, during which patients underwent a pulmonary function test.

Of the 137 patients who underwent a pulmonary function test 2 weeks after discharge, 51.8% were male, and the mean age was 47 years. Only 19.7% of the patients were identified as having severe COVID-19-induced pneumonia. The pulmonary function tests showed that for a small number of patients the forced expiratory volume in one second/forced vital capacity ratio (FEV1/FVC)/% values were <70%, and the mean forced inspiratory volume (IVC) and FVC values were 2.4±0.7 and 3.2±0.8 L, respectively. In severe cases, 88.9% of patients had an IVC <80% of the predicted value, and 55.6% of patients had an FVC <80% of the predicted value. The proportion of patients with maximum expiratory flow rate at 25%, 50% and 75% of the vital capacity (MEF25, MEF50, and MEF75) values <70% were 55.6%, 40.7%, and 25.9%, respectively. In the non-severe group, 79.1% of patients had an IVC <80% of the predicted value, and 16.4% of patients had an FVC <80% of the predicted value. The mean MEF25, MEF50, and MEF75 <70% values were 57.3%, 30%, and 13.6%, respectively.

Our results demonstrated that the pulmonary function of patients with COVID-19-induced pneumonia predominantly manifested as restrictive ventilation disorder and small airway obstruction, which was increased in critically ill patients.