Effects of non-invasive mechanical ventilation with two pressures in the treatment of adults with Covid-19 who developed subcutaneous emphysema: a narrative review

Abstract

Objective: To discuss possible relationships between non-invasive mechanical ventilation (NIV) for patients with Covid-19 and subcutaneous emphysema. Bibliographic review: Among the intervention measures used and recommended for Covid-19 is non-invasive positive pressure. The literature indicates an improvement in the clinical outcome with the use of non-invasive positive pressure, however the presence of subcutaneous emphysema was a reality for some patients undergoing the non-invasive ventilation procedure. This association between non-invasive ventilation and the development of subcutaneous emphysema was intensified for patients with Covid-19. Final considerations: Subcutaneous emphysema can be caused both by the increase in intrathoracic pressure promoted by the use of NIV, and by the fragility of the lung parenchyma and inflammatory mechanisms caused by the disease. Some authors have suggested that the mechanism of subcutaneous emphysema formation may be caused by Covid-19, which generates alveolar damage so intense that it makes the alveolar wall prone to rupture and that it can be potentiated by any factor that increases intra-alveolar pressure, the possible causative mechanisms being: cough, inspiratory effort and use of NIV.