Noninvasive ventilation strategies for patients with severe or critical COVID-19: A rapid review of clinical outcomes

Objectives

To examine whether high flow nasal oxygen (HFNO), continuous positive airway pressure (CPAP), or noninvasive ventilation (NIV) strategies impact mortality, the need for invasive mechanical ventilation (IMV), or hospital and intensive care unit (ICU) length of stay compared to standard oxygen therapy (SOT) or each other in patients with severe or critical COVID-19 with acute hypoxemic respiratory failure.

Methods

A rapid review of randomized controlled trials (RCTs) identified through published systematic and rapid reviews supplemented with a search of bibliographic databases. RCTs were eligible if they compared HFNO, CPAP, or NIV to SOT or another ventilation strategy. Studies were screened, selected, and extracted by a single reviewer and checked by a second reviewer. We assessed risk of bias of included studies using the Cochrane ‘Risk of bias’ tool and used the grading of recommendations, assessment, development, and evaluation (GRADE) approach to judge the certainty of the evidence for mortality, need for IMV, and hospital and ICU length of stay. We sought RCT evidence for non-COVID-19 patients with acute hypoxemic respiratory failure and acute respiratory distress to inform additional comparisons and to supplement the available data for COVID-19.

Results

A total of 5 RCTs comparing ventilation strategies in patients with severe or critical COVID-19 were included. Patient and study characteristics were extracted and evidence and certainty of evidence assessments were completed for comparisons of HFNO and CPAP to standard oxygen therapy and NIV and CPAP to HFNO. An additional 22 RCTs of non-COVID-19 patients were also included and considered.

Results from meta-analysis suggest reductions in mortality and IMV with HFNO (RR mortality 0.87 (0.66-1.13), IMV 0.89 (0.77-1.03); low quality evidence) or CPAP (RR mortality 0.87 (0.64-1.18) low quality evidence, IMV 0.81 (0.67-0.98) moderate quality evidence) compared to SOT. Helmet NIV may reduce IMV (RR 0.69 (0.43-1.09)) and CPAP may reduce IMV (RR 0.69 (0.43-1.09)) and hospital (1.67 days fewer (5.43 fewer-2.09 more) or ICU length of stay (1.02 days fewer (3.97 fewer-1.93 more)) compared to HFNO (low quality evidence).

Conclusions

This rapid systematic review highlights the available evidence to support the use of noninvasive ventilation strategies including high flow nasal oxygen, noninvasive ventiltaion (e.g., BiPAP), or CPAP in hospitalized patients with severe or critical COVID-19 and acute hypoxemic respiratory failure who do not need emergent intubation. Findings based on moderate to very low certainty evidence suggest that noninvasive ventilation may be considered as an alternative to standard oxygen therapy to reduce hypoxemia and dyspnea. Additional high quality RCTs are warranted to reduce uncertainty and to fill in important knowledge gaps.