Pulmonary Function and Radiologic Features in Survivors of Critical COVID-19

Abstract

Background More than 20% of hospitalized patients with coronavirus disease 2019 (COVID-19) develop acute respiratory distress syndrome (ARDS) requiring intensive care unit (ICU) admission. The long-term respiratory sequelae in ICU survivors remain unclear. Research question what are the major long-term pulmonary sequelae in critical COVID-19 survivors? Study Design and Methods Consecutive patients with COVID-19 requiring ICU admission were recruited and evaluated 3 months after hospitalization discharge. The follow-up comprised symptom and quality of life, anxiety and depression questionnaires, pulmonary function tests, exercise test (6-minute walking test (6MWT)) and chest computed tomography (CT). Results 125 ICU patients with ARDS secondary to COVID-19 were recruited between March and June 2020. At the 3-month follow-up, 62 patients were available for pulmonary evaluation. The most frequent symptoms were dyspnea (46.7%), and cough (34.4%). Eighty-two percent of patients showed a lung diffusing capacity of less than 80%. The median (IQR) distance in the 6MWT was 400 (362;440) meters. CT scans were abnormal in 70.2% of patients, showing reticular lesions in 49.1% and fibrotic patterns in 21.1%. Patients with more severe alterations on chest CT had worse pulmonary function and presented more degrees of desaturation in the 6MWT. Factors associated with the severity of lung damage on chest CT were age and length of invasive mechanical ventilation during the ICU stay. Interpretation Pulmonary structural abnormalities and functional impairment are highly prevalent in surviving ICU patients with ARDS secondary to COVID-19 3 months after hospital discharge. Pulmonary evaluation should be considered for all critical COVID-19 survivors 3 months post discharge.

On the Single and Multiple Associations of COVID-19 Post-acute Sequelae: 6-month Prospective Cohort Study

“…We found that the most common abnormal CT patterns were bilateral lung involvement, subpleural reticular, ground-glass opacity density with a peripheral location, which agrees with the previous results 8,10,25,32 . Our study revealed a signi cant robust positive single correlation between the abnormal CT ndings and male sex, age > 59 years, ex-smoker, and abnormal radiography, as well as multiple correlations, except for ex-smoker.…”

Alterations in Respiratory Function Test Three Months after Hospitalisation for COVID-19 Pneumonia: Value of Determining Nitric Oxide Diffusion

“…Furthermore, the few series that have been published regarding functional alterations detected three-to-four months after a COVID-19 pneumonic episode mainly examined the DL CO [1][2][3][4][5][6][7][8][9][10]. As shown in the table summarising these studies (Table 7), and despite the fact that there is little variation in the percentage over the reference value of DL CO , when the alteration was defined by a decrease under 80% in the theoretical percentage (51-57%), except for series that include only post-ICU patients [10]; however, when this was measured as a decrease below the LLN, DL CO alteration ranged from 17% in our work to 24% as reported by Lerum et al [1], and 34% in another study nine weeks after discharge [32]. In other studies, the relationship between predictor variables and lung involvement was enhanced by different linear correlation analyses without defining specific cut-off points for the definition of DL CO alteration [6,8].…”

“…To date, only a limited number of studies have been published that analysed the clinical and functional alterations of patients hospitalised for SARS-COV-2 pneumonia, 3-4 months after their hospital discharge [1][2][3][4][5][6][7][8][9][10]. In these cases of severe COVID-19 pneumonia, the most frequently described alterations are a decrease in forced vital capacity (FVC), carbon monoxide transfer capacity (DL CO ), total lung capacity, and reduction in the 6-min walk test (6MWT) [1][2][3][4][5][6][7][8][9][10]. However, the results described in these studies are not homogeneous.…”

“…Although the most frequently described alteration was a decrease in DL CO , the reported number of patients affected by this pathology varies between 15% and 80%. Moreover, some studies define DL CO according to the percentage of a reference value, while others define it in reference to the lower limit of normality (LLN) [1][2][3][4][5][6][7][8][9][10].…”

Extension of Collagen Deposition in COVID-19 Post Mortem Lung Samples and Computed Tomography Analysis Findings

“…Evidence at hospital discharge shows that nearly half of survivors of COVID-19 have impaired lung diffusing capacity for carbon monoxide, a quarter have reduced total lung capacity, and this is correlated with the severity of disease [ 20 ]. Furthermore, 55% to 80% of COVID-19 patients show impaired pulmonary function and radiologic abnormalities three months after ICU discharge, while 21% show fibrotic patterns at the computed tomography (CT) [ 17 , 21 , 22 ]. It is still unclear whether patients will show recovery over time or irreversible fibrosis will develop.…”