Impact of coronavirus disease 2019 on pulmonary function in early convalescence phase

Abstract

Objective: This study investigated the influence of Coronavirus Disease 2019 (COVID-19) on lung function in early convalescence phase. Methods: A retrospective study of COVID-19 patients at the Fifth Affiliated Hospital of Sun Yat-sen University were conducted, with serial assessments including lung volumes (TLC), spirometry (FVC, FEV1), lung diffusing capacity for carbon monoxide (DLCO),respiratory muscle strength, 6-min walking distance (6MWD) and high resolution CT being collected at 30 days after discharged.Results: Fifty-seven patients completed the serial assessments. There were 40 non-severe cases and 17 severe cases. Thirty-one patients (54.3%) had abnormal CT findings. Abnormalities were detected in the pulmonary function tests in 43 (75.4%) of the patients. Six (10.5%), 5(8.7%), 25(43.8%) 7(12.3%), and 30 (52.6%) patients had FVC, FEV1, FEV1/FVC ratio, TLC, and DLCO values less than 80% of predicted values, respectively. 28 (49.1%) and 13 (22.8%) patients had PImax and PEmax values less than 80% of the corresponding predicted values. Compared with non-severe cases, severe patients showed higher incidence of DLCO impairment (75.6%vs42.5%, p = 0.019), higher lung total severity score (TSS) and R20, and significantly lower percentage of predicted TLC and 6MWD. No significant correlation between TSS and pulmonary function parameters was found during follow-up visit. Conclusion: Impaired diffusing-capacity, lower respiratory muscle strength, and lung imaging abnormalities were detected in more than half of the COVID-19 patients in early convalescence phase. Compared with non-severe cases, severe patients had a higher incidence of DLCO impairment and encountered more TLC decrease and 6MWD decline.

Chest CT in COVID-19 pneumonia: what are the findings in mid-term follow-up?

“…It is worth mentioning that majority of the patients with residual disease had a mild disease in their follow-up CT, based on the CT severity score, even though their initial CT severity score was higher in comparison to patients with the resolved disease. Regarding the pattern of lung involvement, patients with residual disease had GGO or peripheral parenchymal bands or a combination of them in the primary sites of the infection, which may be representative of early fibrotic or interstitial lung disease [ 18 ]. Similar findings were observed in some prior studies on long-term follow-up of influenza A pneumonia [ 24 , 25 ]; however, patients in our study did not show evidences of bronchiectasis, pneumatocele, or bullous cyst formation.…”

“…For example, a study by Liu N. et al on the relationship between dynamic changes of chest CT follow-up in COVID-19 and clinical typing of the disease showed that the occurrence rate of ground-glass opacity, crazy paving pattern, pleural thickening, or adhesion is higher in severe and critical group [ 17 ]. Although some of these reports suggest that chest CT scan findings of patients are improving with proper care, there are still studies that demonstrate many abnormal imaging findings at the time of discharge, including evidence of fibrosis [ 13 , 18 ]. For example, a study by Huang et al on follow-up COVID-19 patients 30 days after discharge showed that more than half of the patients still had residual abnormalities on CT scans, and in cases with initial severe pulmonary involvement, fibrosis was observed at the site of involvement [ 18 ].…”

“…Although some of these reports suggest that chest CT scan findings of patients are improving with proper care, there are still studies that demonstrate many abnormal imaging findings at the time of discharge, including evidence of fibrosis [ 13 , 18 ]. For example, a study by Huang et al on follow-up COVID-19 patients 30 days after discharge showed that more than half of the patients still had residual abnormalities on CT scans, and in cases with initial severe pulmonary involvement, fibrosis was observed at the site of involvement [ 18 ].…”

Intranasal exposure of African green monkeys to SARS-CoV-2 results in acute phase pneumonia with shedding and lung injury still present in the early convalescence phase

“…Our ndings regarding lung injury in the three AGMs that were euthanized at 34 dpi during early convalescence are consistent with the limited human COVID-19 studies that have been reported so far. For example, a recent study of fty-seven COVID-19 patients in China was completed during the early convalescence phase, approximately 30 days after discharge [23]. The study included 40 non-severe cases and 17 severe cases.…”

Effect of respiratory rehabilitation training on elderly patients with COVID-19

“…[ 16 ] For COVID-19 patients, due to lung injuries, the lung functions will be weakened, and accordingly, the labor ability and exercise tolerance will also be impaired, thus seriously affecting the quality of life. [ 17 – 20 ] For COVID-19 patients who have been cured and discharged from hospitals, the rehabilitation treatment in the later stages is very important. [ 21 , 22 ]…”