The optimal chest compression rate (CCR) and chest compression depth (CCD) combination associated with a favorable neurologic outcome after out-of-hospital cardiac arrest (OHCA) was 105-109 compressions/min (cpm) and 4.5-5 cm depth, according to study results published in JAMA Cardiology.
In this cohort study, researchers used data from the National Institutes of Health clinical trials network database to select patients who had participated in the resuscitation outcomes consortium prehospital resuscitation impedance valve and early vs delayed analysis trial between June 2007 and November 2009 (N=3643). Eligible participants had intact sets of simultaneous CCR-CCD recordings during the first 5 minutes of emergency medical services (EMS)-performed cardiopulmonary resuscitation (CPR).
Survival probability was significantly higher when CPR was performed within 20% of 107 cpm and a depth of 4.7 cm (6% vs 4.3% outside of the range; odds ratio [OR] 1.44; 95% CI, 1.07-1.94; P =.02). This identified CCR-CCD combination was also significantly associated with higher probabilities of survival when the CPR device was compared with standard CPR (OR 1.9; 95% CI, 1.06-3.38; P =.03).
Investigators indicated that this study is limited by findings that may not be universally applicable and should be further validated and examined for modifications with changes in certain variables over time. In addition, the findings are not entirely representative of all circumstances, as they involved EMS systems with presumably seasoned 911 agencies and well-monitored OHCA cases.
According to researchers, even if the results simply reflect a subset of EMS personnel who are more focused and trained in resuscitative tasks, those factors should serve largely to better reinforce the reliability of the study’s findings. More than half of the patients were found to be in CCR-CCD grids beyond a calculated optimal target range of within 20%. The study cohort comprised patients who had simultaneous recordings of CCR and CCD performed; however, in many settings, simultaneous CPR is not the case. The quality of chest wall recoil was not available, and no information regarding the actual performance of assisted ventilation was provided.
The same peak combination of 107 cpm and 4.7 cm depth for CPR was found to be optimal regardless of age, sex, presenting cardiac rhythm, or use of an impedance threshold device.
Improved survival with impedance threshold device use seemed to be dependent on providing the optimal combination of CCR and CCD. According to researchers, these findings merit further validation and should be considered in future CPR investigations.
Duval S, Pepe PE, Aufderheide TP, et al. Optimal combination of compression rate and depth during cardiopulmonary resuscitation for functionally favorable survival [published online August 14, 2019]. JAMA Cardiol. doi:10.1001/jamacardio.2019.2717