Mechanical Versus Manual Ventilation During Cardiopulmonary Resuscitation: A Systematic Review and Meta-Analysis

BackgroundManual bag-valve ventilation during cardiopulmonary resuscitation (CPR) is prone to substantial variability in tidal volume and respiratory rate, frequently resulting in hyperventilation. The clinical effectiveness of mechanical ventilation as an alternative strategy remains uncertain. ObjectivesThis systematic review and meta-analysis compared mechanical versus manual ventilation during adult CPR to assess return of spontaneous circulation (ROSC), survival to hospital discharge, and neurological outcomes. MethodsWe searched PubMed, Embase, and Scopus (inception through October 2025) for randomized controlled trials and observational studies comparing mechanical and manual ventilation during adult CPR. We conducted separate meta-analyses for randomized trials and observational studies using random-effects models and assessed evidence certainty using GRADE methodology. Primary outcomes were ROSC, survival to discharge, and favorable neurological outcome (Cerebral Performance Category 1-2). ResultsEight studies (5,130 patients) met inclusion criteria. Mechanical ventilation was associated with higher ROSC (odds ratio [OR] 1.22; 95% confidence interval [CI] 1.07-1.38; p=0.002; I{superscript 2}=8%), survival to discharge (OR 1.39; 95% CI 1.08-1.77; p=0.009; I{superscript 2}=0%), and favorable neurological outcome (OR 1.61; 95% CI 1.04-2.48; p=0.03; I{superscript 2}=0%) compared with manual ventilation. In randomized trials (n=120), mechanical ventilation showed a trend toward improved ROSC (OR 1.49; 95% CI 0.73-3.07; p=0.27) but lacked statistical significance. Observational studies (n=7,081) demonstrated an association between mechanical ventilation and higher ROSC (OR 1.21; 95% CI 1.03-1.42; p=0.02; I{superscript 2}=34%). Post-ROSC arterial blood gases showed improved oxygenation (mean difference 13.01 mmHg higher pO2 ; p<0.0001) and lower pCO2 levels (mean difference 15.12 mmHg lower; p<0.00001) with mechanical ventilation. GRADE assessment indicated low-certainty evidence for clinical outcomes and moderate-certainty evidence for physiological outcomes. ConclusionsMechanical ventilation during CPR was associated with higher rates of ROSC, survival, and favourable neurological outcomes, along with more controlled post-ROSC physiological parameters. However, the certainty of evidence is low, driven largely by confounded observational data and limited randomized trial evidence. These findings are hypothesis-generating and should not be interpreted as causal. Confirmation in adequately powered randomized controlled trials is required before changes to practice or guidelines can be recommended. WHAT IS NEW?O_LIThis systematic review and meta-analysis, stratified by study design, synthesizes the available evidence comparing mechanical and manual ventilation during adult cardiopulmonary resuscitation across eight studies involving 5,130 patients. C_LIO_LIMechanical ventilation was associated with higher rates of return of spontaneous circulation, survival to hospital discharge, and favorable neurological outcome compared with manual ventilation; however, these associations are derived largely from observational data with low certainty of evidence. C_LIO_LIMechanical ventilation demonstrated more consistent post-resuscitation arterial blood gas parameters--higher oxygenation and lower carbon dioxide levels--suggesting physiologic benefits, although these findings also require confirmation in randomized trials. C_LI CLINICAL IMPLICATIONS?O_LIMechanical ventilation may offer a more standardized approach to delivering tidal volumes and respiratory rates during CPR, potentially mitigating the variability and risk of hyperventilation inherent to manual bag-valve ventilation. C_LIO_LIBecause the evidence supporting improved clinical outcomes is low certainty and primarily observational, the observed associations should not be interpreted as causal. These results are hypothesis-generating and highlight an important area for further investigation rather than indicating definitive clinical benefit. C_LIO_LIIf mechanical ventilation is used during CPR, implementation should prioritize protocolized ventilator settings (e.g., tidal volume 6-7 mL/kg and respiratory rate 10 breaths/min) and strict adherence to high-quality chest compressions. C_LIO_LIAdequately powered randomized controlled trials are needed to determine whether mechanical ventilation confers true clinical benefit and to inform future guideline recommendations. C_LI