Abstract
Rationale Post-COVID19 survivors frequently have dyspnea that can lead to exercise intolerance and lower quality of life. Despite recent advances, the pathophysiological mechanisms of exercise intolerance in the post-COVID19 patients remain incompletely characterized.
Objectives To clarify the mechanisms of exercise intolerance in post-COVID19 survivors after hospitalization.
Methods Prospective study evaluated consecutive patients previously hospitalized due to moderate-to-severe/critical COVID19. Within 90±10 days (mean±sd) of COVID19 acute symptoms onset, patients underwent a comprehensive cardiopulmonary assessment, including a cardiopulmonary exercise testing with earlobe arterialized capillary blood gas analysis.
Measurements and Main Results Eighty-seven patients were evaluated, their mean±sd peak oxygen consumption were 19.5±5.0 ml kg−1·min−1, and the tertiles were: ≤17.0, 17.1–22.2 and ≥22.3 ml kg−1·min−1. Hospitalization severity was similar among the three groups; however, at the follow-up visit, they reported a greater sensation of dyspnea, along with indices of impaired pulmonary function, and abnormal ventilatory, gas-exchange and metabolic responses during exercise compared to patients with peak oxygen consumption >17 ml kg−1·min−1. By multivariate logistic regression analysis (ROC curve analysis) adjusted for age, sex and pulmonary embolism, a peak dead space fraction of tidal volume ≥29 and a resting forced vital capacity ≤80%predicted were independent predictors of reduced peak oxygen consumption.
Conclusions Exercise intolerance in the post-COVID19 survivors was related to a high dead space fraction of tidal volume at peak exercise and a decreased resting forced vital capacity, suggesting that both pulmonary microcirculation injury and ventilatory impairment could influence aerobic capacity in this patient population.
Footnotes
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Conflict of interest: Mariana L Lafetá has nothing to disclose.
Conflict of interest: Vitor C Souza has nothing to disclose.
Conflict of interest: Thaís C F Menezes has nothing to disclose.
Conflict of interest: Carlos G Y Verrastro has nothing to disclose.
Conflict of interest: Frederico J Mancuso has nothing to disclose.
Conflict of interest: André Luis p Albuquerque has nothing to disclose.
Conflict of interest: Suzana E Tanni reports be President of Sao Paulo Thoracic Society, outside the submitted work.
Conflict of interest: Meyer Izbicki has nothing to disclose.
Conflict of interest: Júlio p Carlstron has nothing to disclose.
Conflict of interest: Luiz Eduardo Nery has nothing to disclose.
Conflict of interest: Rudolf K F Oliveira report grants from National Council for Scientific and Technological Development (CNPq, Brazil, grant 313284/2021-0) and personal fees from Janssen Brazil, outside the submitted work.
Conflict of interest: Priscila A Sperandio has nothing to disclose.
Conflict of interest: Eloara V M Ferreira reports speaker fees from Janssen, and personal fees from Aché, Aztrazeneca, Bayer, Boeringer, GSK, Novo Nordisk, Jassen-Cilag J&J, Zambon, outside the submitted work.
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