The main cause of death in patients with the coronavirus disease (COVID-19) is hypoxemic respiratory failure and severe acute respiratory distress syndrome (ARDS). Symptomatic patients with rapidly falling oxygen saturation levels and dyspnoea are put on either invasive or non-invasive mechanical ventilation to manage respiratory failure.
This is a living systematic review, done to review the effects of ventilation techniques used in the treatment of coronavirus infections, including the one that causes COVID-19. 129 different studies of varying designs, done on COVID-19, SARS and MERS were chosen, of which only 11 studies adjusted for crucial confounders. This study compared the mortality rates associated with the different types of ventilation and the risk of transmission of the virus to healthcare workers from aerosol-generating procedures (AGPs).
It was found that patients with COVID-19 showed a comparatively higher mortality with non-invasive ventilation (NIV) than with invasive mechanical ventilation (IMV). But 2 studies, conducted on MERS and SARS patients respectively, revealed a low evidence-based reduction in mortality with NIV. Similarly, 2 studies done on SARS patients again reported a low evidence-based reduction in mortality with NIV as compared to no mechanical ventilation. 2 more systematic reviews reported a significant reduction in mortality with NIV compared to conventional oxygen therapy. 1 RCT comparing the use of HFNC with standard oxygen therapy revealed that the use of HFNC reduced the need for IMV in COVID-19 patients. Several other studies reported that the odds of healthcare workers contracting COVID-19 from AGPs was significantly high.
Newer evidence from 6 more studies also suggest that the use of NIV and IMV may reduce the mortality but also elevate the risk of transmission of COVID-19 to healthcare workers.