Influence of different ventilation strategies during cardiopulmonary resuscitation on the return of spontaneous circulation in out-of-hospital cardiac arrest: a retrospective study from the German Resuscitation Registry

To evaluate the association of different intra-arrest ventilation strategies with return of spontaneous circulation (ROSC), hospital admission, and 24-hour survival among adult OHCA patients. This retrospective cross-sectional study analyzed data from the German Resuscitation Registry. Adult patients (≥18 years) with non-traumatic out-of-hospital cardiac arrest (OHCA) between March 2016 and March 2023 were included if they received CPR, endotracheal intubation before ROSC, and had a documented ventilation strategy. Four ventilation modes were compared: Intermittent Positive Pressure Ventilation (IPPV), Chest Compression Synchronized Ventilation (CCSV), biphasic positive airway pressure (BIPAP), and manual bag-valve ventilation (Manually). ROSC observed (ROSCobs) was compared with expected ROSC (ROSCexp) based on the ROSC after cardiac arrest score (RACA). Secondary outcomes were hospital admission status and 24-hour survival. Among 3,195 patients (IPPV: 1,865; CCSV: 194; BIPAP: 81; Manually: 1,055), ROSC occurred in 44% (IPPV), 40% (CCSV), 49% (BIPAP), and 39% (Manually). IPPV showed a significant positive deviation from ROSCexp (+2.7%, p=0.0005). No other strategy reached statistical significance. Patients ventilated with CCSV had a lower rate of admission with ROSC (24%) and higher rates of admission under ongoing CPR (34%). In the manual bag-valve ventilated group more patients died on scene (59%). Respirator controlled ventilation with IPPV modestly but significantly exceeded expected ROSC rates in patients with non-traumatic OHCA. CCSV, the mode designed specifically for ventilation during CPR, does not seem to be superior to manual bag-valve ventilation. Randomized controlled trials are needed to refine mechanical ventilation strategies in CPR.