Ventilation parameters during adult cardiopulmonary resuscitation: a systematic review

Background: Effective ventilation during cardiopulmonary resuscitation (CPR) is challenging, with limited evidence to guide optimal rates, volumes, and other parameters. This systematic review, part of the continuous evidence evaluation process for the International Liaison Committee on Resuscitation, examined whether specific tidal volumes, respiratory rates, inspiratory times, or positive end-expiratory pressure (PEEP) improve outcomes. Methods: Studies of adults in any setting (in-hospital or out-of-hospital cardiac arrest) receiving ventilation were included if they compared specific tidal volumes, respiratory rates, inspiratory times, or PEEP. MEDLINE, EMBASE, and CENTRAL were searched from inception to November 10, 2025. Risk of bias was assessed using RoB 2.0 and ROBINS-I; certainty of evidence was evaluated with GRADE. Registered in PROSPERO (CRD420251070065). Results: Of 3021 records, 11 studies (3 randomized trials, 8 observational) met eligibility criteria. Certainty of evidence was very low, limited by bias, inconsistency, indirectness, and imprecision. Due to heterogeneity, results were reported narratively using Synthesis Without Meta-Analysis (SWiM) guidelines. Ventilation rates showed mixed associations with neurological, survival, and return of spontaneous circulation (ROSC) outcomes; some studies indicated harm with lower ventilation rates. Most found no differences between higher and lower tidal volumes, although very low tidal volumes were associated with worse outcomes in some studies. When impedance-detected ventilations occurred in ≥50% of chest compression pauses during 30:2 CPR, survival and ROSC were higher. Conclusion: Evidence on optimal ventilation during CPR is inconsistent and of very low certainty. Very low ventilation rates and tidal volumes may be harmful. Future research should use robust designs to define evidence-based ventilation targets.