Ventilation Techniques and Risk for Transmission of Coronavirus Disease, Including COVID-19: A Living Systematic Review of Multiple Streams of Evidence

Abstract

Background: Mechanical ventilation is used to treat respiratory failure in coronavirus disease 2019 (COVID-19).

Purpose: To review multiple streams of evidence regarding the benefits and harms of ventilation techniques for coronavirus infections, including that causing COVID-19.

Data sources: 21 standard, World Health Organization-specific and COVID-19-specific databases, without language restrictions, until 1 May 2020.

Study selection: Studies of any design and language comparing different oxygenation approaches in patients with coronavirus infections, including severe acute respiratory syndrome (SARS) or Middle East respiratory syndrome (MERS), or with hypoxemic respiratory failure. Animal, mechanistic, laboratory, and preclinical evidence was gathered regarding aerosol dispersion of coronavirus. Studies evaluating risk for virus transmission to health care workers from aerosol-generating procedures (AGPs) were included.

Data extraction: Independent and duplicate screening, data abstraction, and risk-of-bias assessment (GRADE for certainty of evidence and AMSTAR 2 for included systematic reviews).

Data synthesis: 123 studies were eligible (45 on COVID-19, 70 on SARS, 8 on MERS), but only 5 studies (1 on COVID-19, 3 on SARS, 1 on MERS) adjusted for important confounders. A study in hospitalized patients with COVID-19 reported slightly higher mortality with noninvasive ventilation (NIV) than with invasive mechanical ventilation (IMV), but 2 opposing studies, 1 in patients with MERS and 1 in patients with SARS, suggest a reduction in mortality with NIV (very-low-certainty evidence). Two studies in patients with SARS report a reduction in mortality with NIV compared with no mechanical ventilation (low-certainty evidence). Two systematic reviews suggest a large reduction in mortality with NIV compared with conventional oxygen therapy. Other included studies suggest increased odds of transmission from AGPs.

Limitation: Direct studies in COVID-19 are limited and poorly reported.

Conclusion: Indirect and low-certainty evidence suggests that use of NIV, similar to IMV, probably reduces mortality but may increase the risk for transmission of COVID-19 to health care workers.

Primary funding source: World Health Organization. (PROSPERO: CRD42020178187).

Figure 1.

Mortality with NIV versus IMV. Three studies (21, 29, 31) comparing NIV with IMV suggested both an increase and a reduction in mortality. COVID-19 = coronavirus disease 2019; IMV = invasive mechanical ventilation; IV = inverse variance; MERS = Middle East respiratory syndrome; NIV = noninvasive ventilation; SARS = severe acute respiratory syndrome.

Figure 2.

Mortality with NIV compared with no MV. One RCT (32) suggests a reduction in mortality, but there were only 3 events in 60 patients in total, causing imprecision. The nonrandomized study by Xu and colleagues (12) showed a reduction in mortality. IV = inverse variance; MERS = Middle East respiratory syndrome; MV = mechanical ventilation; NIV = noninvasive ventilation; NRS = nonrandomized study; RCT = randomized controlled trial; SARS = severe acute respiratory syndrome.