Residual respiratory impairment after COVID-19 pneumonia
Authors: Lombardi Francesco , Calabrese Angelo , Iovene Bruno , Pierandrei Chiara , Lerede Marialessia , Varone Francesco , Richeldi Luca , Sgalla Giacomo ,   the Gemelli Against COVID-19 Post-Acute Care Study Group, Landi Francesco , Gremese Elisa , Bernabei Roberto , Fantoni Massimo , Gasbarrini Antonio , Romano Settanni Carlo , Benvenuto Francesca , Bramato Giulia , Carfì Angelo , Ciciarello Francesca , Rita Lo Monaco Maria , Maria Martone Anna , Marzetti Emanuele , Napolitano Carmen , Pagano Francesco , Rocchi Sara , Rota Elisabetta , Salerno Andrea , Tosato Matteo , Tritto Marcello , Calvani Riccardo , Catalano Lucio , Picca Anna , Savera Giulia , Tamburrini Enrica , Borghetti Alberto , Di Gianbenedetto Simona , Murri Rita , Cingolani Antonella , Ventura Giulio , Taddei Eleonora , Moschese Davide , Ciccullo Arturo , Stella Leonardo , Addolorato Giovanni , Franceschi Francesco , Mingrone Gertrude , Assunta Zocco Maria , Sanguinetti Mauirizio , Cattani Paola , Marchetti Simona , Bizzarro Alessandro , Lauria Alessandra , Rizzo Stanislao , Cristina Savastano Maria , Gambini Gloria , Grazia Cozzupoli Maria , Culiersi Carola , Cesare Passali Giulio , Paludetti Gaetano , Galli Jacopo , Crudo Fabrizio , Di Cintio Giovanni , Longobardi Ylenia , Tricarico Laura , Santantonio Mariaconsiglia , Buonsenso Danilo , Valentini Piero , Pata Davide , Sinatti Davide , De Rose Cristina. , Richeldi Luca , Lombardi Francesco , Calabrese Aangelo , Sani Gabriele , Janiri Delfina , Giuseppin Giulia , Molinaro Marzia , Modica Marco , Natale Luigi , Rita Larici Anna , Marano Riccardo , Paglionico Annamaria , Petricca Luca , Gigante Laura , Natalello Gerlando , Laura. Fedele Anna , Maria Lizzio Marco , Santoliquido Angelo , Santoro Luca , Nesci Antonio , Popolla Valentina 
Published: July 2021

Abstract
Introduction
The novel coronavirus SARS-Cov-2 can infect the respiratory tract causing a spectrum of disease varying from mild to fatal pneumonia, and known as COVID-19. Ongoing clinical research is assessing the potential for long-term respiratory sequelae in these patients. We assessed the respiratory function in a cohort of patients after recovering from SARS-Cov-2 infection, stratified according to PaO2/FiO2 (p/F) values.

Method
Approximately one month after hospital discharge, 86 COVID-19 patients underwent physical examination, arterial blood gas (ABG) analysis, pulmonary function tests (PFTs), and six-minute walk test (6MWT). Patients were also asked to quantify the severity of dyspnoea and cough before, during, and after hospitalization using a visual analogic scale (VAS). Seventy-six subjects with ABG during hospitalization were stratified in three groups according to their worst p/F values: above 300 (n = 38), between 200 and 300 (n = 30) and below 200 (n = 20).

Results
On PFTs, lung volumes were overall preserved yet, mean percent predicted residual volume was slightly reduced (74.8 ± 18.1%). Percent predicted diffusing capacity for carbon monoxide (DLCO) was also mildly reduced (77.2 ± 16.5%). Patients reported residual breathlessness at the time of the visit (VAS 19.8, p < 0.001). Patients with p/F below 200 during hospitalization had lower percent predicted forced vital capacity (p = 0.005), lower percent predicted total lung capacity (p = 0.012), lower DLCO (p < 0.001) and shorter 6MWT distance (p = 0.004) than patients with higher p/F.

Conclusion
Approximately one month after hospital discharge, patients with COVID-19 can have residual respiratory impairment, including lower exercise tolerance. The extent of this impairment seems to correlate with the severity of respiratory failure during hospitalization.