Association of Mechanical Cardiopulmonary Resuscitation Device Use With Cardiac Arrest Outcomes
Authors: David G. Buckler, Rita V. Burke, Maryam Y. Naim, Andrew MacPherson, Richard N. Bradley, Benjamin S. Abella, Joseph W. Rossano
Journal: Circulation (2016)

T he use of mechanical cardiopulmonary resuscitation devices (mCPR) to deliver CPR has become more widespread, although a survival advantage has not been demonstrated in randomized, controlled trials. 1-3Little is known about real-world use of mCPR or the association with outcomes.CARES (Cardiac Arrest Registry to Enhance Survival), a US national registry of outof-hospital cardiac arrest, 4 was analyzed for adults with nontraumatic out-of-hospital cardiac arrest from January 2013 to December 2015.Patients treated with mCPR were compared with patients receiving manual CPR only.Time of arrest, time of first CPR, and timing of interventions were not reliably reported.However, patients had information about when return of spontaneous circulation (ROSC) occurred before or after advanced life support (ALS) measures.As part of a subgroup analysis, patients with ROSC before ALS were excluded because of the decreased likelihood of these patients receiving mCPR.The primary outcome of interest was neurologically favorable survival at hospital discharge, defined as a Cerebral Performance Category of 1 or 2. This project was deemed exempt from review by the Children's Hospital of Philadelphia and University of Pennsylvania Institutional Review boards.Statistical analyses included the Student t test and χ 2 test as appropriate.A multivariable logistic regression model was created with the use of stepwise addition to control for Utstein-style arrest characteristics, including age, arrest location, bystander CPR and automated external defibrillator use, witnessed arrest status, initial rhythm, postarrest targeted temperature management, successful advanced airway placement, and impedance threshold device use.Separate analyses were performed for the cohort who did not have ROSC before ALS treatment.Statistical significance was defined as a 2-sided value of P<0.05, and analyses were performed with SAS/STAT version 9.4 (SAS Institute Inc, Cary, NC).During the study period, 80 861 subjects were included in the analysis (Figure).The median age was 62 years (interquartile range, 52-75 years), and 35.1% received bystander CPR.Compared with patients receiving manual CPR, those receiving mCPR were more likely to have an unwitnessed arrest (57.3% versus 55.7%), an automated external defibrillator placed (33.3% versus 28.3%), an advanced airway placed (87.4% versus 79.0%), and an impedance threshold device used (41.8% versus 13.4%) and to undergo prehospital targeted temperature management (16.6%versus 12.2%; P<0.05 for all).From 2013 to 2015, use of mCPR increased from 20.6% to 23.4% (P<0.0001), and mCPR was used at least once by 41.9% (244 of 582) of emergency medical services agencies.For all agencies that used a mechanical device, median mCPR use was 43.9% (interquartile range, 11.9%-59.9%).However, agency use varied greatly, with 21.7% of agencies using mCPR in >75% of arrests and 37.7% using mCPR in <25% of arrests.Survival to hospital discharge and neurologically favorable survival were greater in patients not receiving mCPR (11.3% versus 7.0%, P<0.0001 for overall survival; 9.5% versus 5.6%, P<0.0001 for neurologically favorable survival).