1. In this cluster randomization with crossover trial, continuous chest compressions with asynchronous positive pressure ventilation (PPV) during CPR was not associated with a significantly higher rate of survival to hospital discharge or favorable neurologic function compared to a strategy of chest compressions interrupted for ventilations.
2. The continuous chest compression group had significantly lower rates of hospital transfer and admission, in addition to shorter hospital-free survival compared to the interrupted chest compression groups.
Evidence Rating Level: 1 (Excellent)
Study Rundown: While standard CPR uses chest compressions interrupted for periodic ventilations, these interruptions can reduce blood flow and, in turn, potentially decrease the effectiveness of CPR. Prior observational studies suggested continuous chest compressions for out-of-hospital cardiac arrests were associated with better survival and improved neurologic function. In this cluster randomized control trial with crossover, continuous chest compressions were tested against interrupted chest compressions (30:2 ratio) for ventilations with respect to survival and neurologic function. EMS providers were randomized to each of the groups in cluster format, with cross over to the other group occurring twice per year. Results indicated no significant difference in survival or neurologic function in patients with out-of-hospital cardiac arrest. Limitations of this trial were significant for difference in EMS practice outside of a clinical trial, patients’ imbalances and quality of post-resuscitative care between the groups, and no measurement of oxygenation or minutes of ventilation delivered. Given the lack of difference in strategy, clinical implications continue to be the focus on emergency responders performing good quality CPR as an important component of positive outcomes.
Click to read the study in NEJM
Relevant Reading: Quality of cardiopulmonary resuscitation during out of hospital cardiac arrest.
In-Depth [randomized controlled trial]: This cluster-randomized trial aimed to compare outcomes of survival and neurologic function after continuous chest compressions with PPV versus interrupted chest compressions during CPR. A total of 114 EMS agencies were included and cluster randomized to one of the two treatment arms. Cross-over between the clusters occurred twice per year. The primary outcome was the rate of survival to hospital discharge, while secondary outcomes included using the modified Rankin scale to measure neurologic outcome (scored 0-6, with £3 indicating favorable function).
Of the 23,711 total patients included in the primary analysis, 1129/12,612 (9%) with available data survived until discharge in the intervention group compared to 1072/11,035 (9.7%) with available date in the control group (- 0.7%; 95% [CI], -1.5 to 0.1; p=0.07). 7% of patients in the intervention group demonstrated favorable neurologic function at discharge compared to 7.7% in the control group (-0.6%; 95% [CI], -1.4 to 0.1, p=0.09). Compared to the control group, patients in the intervention group were significantly: less likely to be transported to hospital (-2%; 95% [CI], -3.6 to 0.5; p=0.01); less likely to be admitted to the hospital (-1.3%; 95% [CI], -2.4 to -0.2; p=0.030; likely to have shorter hospital-free survival (mean difference -0.2 days; 95% [CI], -0.3 to -0.1; p=0.004)
Image: PD
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