Mr. Editor

SARS-CoV-2 is a beta-coronavirus of the same subgenus as SARS and MERS viruses, they share the same gene binding receptor, angiotensin converting enzyme (ACE2).¹The spectrum of disease severity is varied, with the mild form being the most frequent (81%), and severe disease present in 14% of cases, with critical presentation being present in 5%, with a mortality of 2.3%.²

The post-pneumonia respiratory sequela caused by beta-Coronaviruses is diffuse alveolar damage with fibrotic lesions; the pathophysiological mechanism is multifactorial, which involves activation of transforming growth factor beta (TGF-β)³, IL1, IL6, MCP1 and TNF-α secondary to epithelial injury and subsequent inflammation. In addition, exposure to high O2 concentrations and effects of barotrauma, caused by advanced oxygen/ventilatory support, activate the pro-fibrotic TGF-β pathway, resulting in aberrant repair characterized by exaggerated deposition of fibroblasts, myofibroblasts and collagen. Forty-seven percent and 25% of patients who survive moderate to severe COVID-19 pneumonia have decreased carbon monoxide diffusion and predicted total lung capacity, respectively.⁴

Respiratory rehabilitation is a tool used by the clinician to improve the physical and psychological condition and quality of life of people suffering from chronic respiratory disease. It is based on individualized management of the patient by applying muscle training, physiotherapy techniques, education, psychological and nutritional evaluation.⁵Respiratory rehabilitation applied in a timely and early manner reduces dyspnea, relieves anxiety and depression. In addition, it could reduce the occurrence of respiratory complications, improve pulmonary dysfunction and reduce the disability rate of hospitalized patients with a diagnosis of moderate to severe COVID-19 at the end of the acute phase.

For aerobic exercises, an extremity cycloergometer is used, with oxygen support to ensure an O₂saturation (SatO₂) greater than 95%, controlled according to the Borg scale and safety heart rate. In addition, it is suggested to use an incentive inspirometer, by flow or volume, considering that the pulmonary sequelae are of restrictive pattern. As for the initial and follow-up evaluation parameters, it is suggested to use the one-minute standing-sitting test or the desaturation test with walking.

Our pulmonology team of a referral hospital for COVID-19 management suggests starting the post-COVID-19 respiratory rehabilitation program as follows (Table 1).