Alternatives to conventional invasive ventilation in viral acute respiratory distress syndrome: a systematic review

Abstract

Rationale: The COVID-19 pandemic caused a shortage of respiratory ventilators, making it essential to explore alternatives to Invasive Mechanical Ventilation (IMV) for patients with acute respiratory distress syndrome caused by respiratory viruses.

Objectives: This study aimed to assess the safety and effectiveness of alternative ventilation strategies compared to IMV in such patients. The primary outcome was mortality.

Methods: A systematic review following the Cochrane guidelines and PRISMA checklist was done, searching on Medline, Cochrane CENTRAL and Embase for indexed literature and regulatory agencies for gray literature. The studies included compared at least one ventilatory alternative, such as High-Flow Nasal Cannula (HFNC), Non-Invasive Mechanical Ventilation (NIMV), or Continuous Positive Airway Pressure (CPAP), to IMV. A weighted mortality Odds ratio (OR) was calculated, and meta-analysis performed if heterogeneity was low.

Measurements/Main Results: Forty-seven studies met the inclusion criteria, including 36 non-randomized, 2 trials, and 9 congress abstracts. From the 36 non-randomized and 9 abstracts, 13 were for NIMV, 7 for CPAP, 6 for HFNC, 5 evaluated multiple interventions simultaneously, and 13 did not correctly distinguish between interventions. OR weighted mortality for NIMV was 0.48 [0.36, 0.64], HFNC had an OR of 0.33 [0.18, 0.57], and CPAP had an OR of 0.53 [0.34, 0.84]. No meta-analysis was performed, and GRADE evaluation showed that the evidence was of very low certainty.

Conclusions: NIMV, HFNC, and CPAP reduce mortality in ARDS caused by respiratory viruses, but the high heterogeneity between studies and the lack of randomized controlled trials (RCTs) highlights the need for further research.