Medium-term impact of COVID-19 on pulmonary function, functional capacity and quality of life

Abstract

BackgroundCoronavirus disease 2019 (COVID-19) has spread worldwide determining a dramatic impact on the healthcare system. Aim of this study is to evaluate mid-term clinical impact of COVID-19 on respiratory function.Methods379 patients were evaluated 4 months after SARS-COV-2 diagnosis. Patients were divided in two groups based on the presence of pneumonia during COVID. Clinical conditions, quality of life, symptomatology, 6-min walking test, pulmonary function test with spirometry and diffusing capacity of carbon monoxide were analysed. Data were compared to clinical evolution during COVID (development of acute respiratory distress syndrome [ARDS], needing of invasive mechanical ventilation [IMV], partial oxygen saturation/ fraction of inspired oxygen [SpO2/FiO2] ratio and pneumonia severity index [PSI]).ResultsAfter a median of 135 days, 260 (68.6%) of 379 patients referred almost one symptom. Patients who developed pneumonia during COVID-19 showed lower SpO2 at rest (p<0.001), SpO2 during 6-min walking test (p<0.001), total lung capacity (p<0.001), airway occlusion pressure after 0.1 s [P0.1] (p=0.02), P0.1/maximal inspiratory pressure [MIP] ratio (p=0.005) and higher Borg category-ratio scale (p=0.006) and modified Medical Research Council breathlessness scale (p=0.003), compared to patients without pneumonia. SpO2/FiO2 ratio and PSI during SARS-COV-2 pneumonia were directly associated with mid-term alteration of partial oxygen saturation at rest (p<0.001), SpO2 during 6-min walking test (p<0.001), residual volume (p<0.001), total lung capacity (respectively p<0.001 and p=0.003) and forced vital capacity (respectively p=0.004, p=0.03).ConclusionLung damage during COVID-19 correlates to the reduction of pulmonary function after 4 months from acute infection.

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

“…These different definitions can influence the capacity of DL CO to predict the functional sequelae of the different variables analysed. However, as we observed in this present work, and consistent with the results from the only published study that evaluated patients six months after infection with SARS-CoV-2 [33], these variables are usually associated with parameters related to the severity of the pneumonic episode (e.g., prognostic scales, value of analytical determinations indicative of greater inflammation) and intensity of the supportive therapy required during patient admission [1][2][3][4][5][6][7][8]. One study found that cardiorespiratory comorbidities and female sex predicted DL CO < 80%, but not DL CO < 60% [7].…”

“…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].…”

“…The scarcity of previous studies evaluating DL NO makes it difficult to contextualise this work within the existing academic literature. 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].…”

“…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].…”