Generation of Aerosols by Noninvasive Respiratory Support Modalities: A Systematic Review and Meta-Analysis

Abstract

Importance: Infection control guidelines have historically classified high-flow nasal oxygen and noninvasive ventilation as aerosol-generating procedures that require specialized infection prevention and control measures.

Objective: To evaluate the current evidence that high-flow nasal oxygen and noninvasive ventilation are associated with pathogen-laden aerosols and aerosol generation.

Data sources: A systematic search of EMBASE and PubMed/MEDLINE up to March 15, 2023, and CINAHL and ClinicalTrials.gov up to August 1, 2023, was performed.

Study selection: Observational and (quasi-)experimental studies of patients or healthy volunteers supported with high-flow nasal oxygen or noninvasive ventilation were selected.

Data extraction and synthesis: Three reviewers were involved in independent study screening, assessment of risk of bias, and data extraction. Data from observational studies were pooled using a random-effects model at both sample and patient levels. Sensitivity analyses were performed to assess the influence of model choice.

Main outcomes and measures: The main outcomes were the detection of pathogens in air samples and the quantity of aerosol particles.

Results: Twenty-four studies were included, of which 12 involved measurements in patients and 15 in healthy volunteers. Five observational studies on SARS-CoV-2 detection in a total of 212 air samples during high-flow nasal oxygen in 152 patients with COVID-19 were pooled for meta-analysis. There was no association between high-flow nasal oxygen and pathogen-laden aerosols (odds ratios for positive samples, 0.73 [95% CI, 0.15-3.55] at the sample level and 0.80 [95% CI, 0.14-4.59] at the patient level). Two studies assessed SARS-CoV-2 detection during noninvasive ventilation (84 air samples from 72 patients). There was no association between noninvasive ventilation and pathogen-laden aerosols (odds ratios for positive samples, 0.38 [95% CI, 0.03-4.63] at the sample level and 0.43 [95% CI, 0.01-27.12] at the patient level). None of the studies in healthy volunteers reported clinically relevant increases in aerosol particle production by high-flow nasal oxygen or noninvasive ventilation.

Conclusions and relevance: This systematic review and meta-analysis found no association between high-flow nasal oxygen or noninvasive ventilation and increased airborne pathogen detection or aerosol generation. These findings argue against classifying high-flow nasal oxygen or noninvasive ventilation as aerosol-generating procedures or differentiating infection prevention and control practices for patients receiving these modalities.

Figure 1.. Random-Effects Meta-Analysis of High-Flow Nasal Oxygen (HFNO) on SARS-CoV-2 Detection in Air Samples From Patients With COVID-19

Forest plots showing the pooled odds ratios (ORs) and 95% CIs of observational studies assessing SARS-CoV-2 detection in air samples from patients with COVID-19 treated with either HFNO or control treatments (unsupported breathing, LFNO, or standard oxygen or nonrebreather mask). Patient-level data are from the study by Thuresson et al. Squares represent the relative weight of each study, and diamond size represents the summary effect size.

Figure 2.. Random-Effects Meta-Analysis of Noninvasive Ventilation (NIV) on SARS-CoV-2 Detection in Air Samples From Patients With COVID-19

Forest plots showing the pooled odds ratios (ORs) and 95% CIs of observational studies assessing SARS-CoV-2 detection in air samples from patients with COVID-19 treated with NIV or control treatments (unsupported breathing, CFNO, or standard oxygen or nonrebreather mask). Patient-level data are from Thuresson et al. Squares represent the relative weight of each study, and diamond size represents the summary effect size.