Respiratory Function at 3 Months After Hospital Discharge in Critically Ill Patients With Covid-19

Background: Up to 20% of patients with COVID-19 get critically ill and require intensive care unit (ICU)admission. At hospital discharge, most patients still have physical and mental limitations, which affect their quality of life. Pulmonaryfunctional alterations in patients with COVID-19 vary from the absence of functional abnormalities to restrictive and diffusion impairments. We aimed to describe pulmonary function abnormalities as well as their impact on the 6-minute walk test (6 MWT) and SF-36 physical component summary (PCS) score in patients with COVID-19 at ≥ 3 months after hospital discharge. Methods: Weincluded 65 patients aged ≥ 18 years with severe COVID-19 confirmed throughreal-time reverse transcriptase-polymerase chain reaction andadmitted to the ICU between April 2020 and October 2021. Patients were evaluated at ≥ 3 months after hospital discharge using the 6 MWT, pulmonary function tests (PFTs), and the PCS score. Results: : Among the included patients, 27patients had abnormal PFT findings, 21 (32.3%) had forced vital capacity < 80%, 17 (26.1%) had forced expiratory volume in 1 s< 80%, and 4 (6.1%) had a maximal mid-expiratory flow< 65%. Compared with patients without abnormal PFT findings, patientswith abnormal PFT findings were older and had significantlyhigher ferritin levels. There were no significant between-group differences ininvasive and noninvasive respiratory support, mechanical ventilation duration, vasopressor use,and renal replacement therapy. However, compared with patients with normalPFT findings, patients with abnormal PFT findings showed asignificantly lower 6-MWT score [78% (0.0–92) vs.95% (75–100), p = 0.01] and worse PCS scores [39.4 (32.1–51.3) vs. 52.0 (47.4–57.3), p = 0.007]. There was an independent association between the PCS scores and PFT findings. Conclusions: : We found that a significant proportion of patients present pulmonary functional alterations ≥ 3 months after discharge from the hospital after treatment forsevere COVID-19; further, these alterations affectphysical functional capacity and quality of life. Trial registration: The trial protocol was approved by the Research Ethics Committee of the Hospital Sao Domingos (Number 5.403.663) in May 12, 2022 and registered in clinical trials. Gov(NCT05249842), February 22, 2022.