Clinical PaperManual vs. integrated automatic load-distributing band CPR with equal survival after out of hospital cardiac arrest. The randomized CIRC trial☆,☆☆
Introduction
High-quality chest compressions (i.e., correct depth, rate, full release and high chest compression fraction) are emphasized by The International Liaison Committee on Resuscitation (ILCOR).1 Mechanical chest compression devices were developed to assist rescuers in giving consistent high-quality compressions.2, 3, 4 A mechanical chest compression device that uses a load distributing band (LDB) has been shown in animal and human studies to improve hemodynamic parameters over manual CPR (M-CPR).5, 6, 7, 8 Studies comparing LDB devices with M-CPR in the setting of out-of-hospital cardiac arrests (OHCA) have produced conflicting results.9, 10, 11, 12 Retrospective studies found improved outcomes,10, 11, 12 but one randomized controlled trial showed worse cerebral performance at hospital discharge in the LDB arm, and consequently the trial was terminated early.9
It is important to determine the role of mechanical CPR in prehospital resuscitation, as it could be a powerful adjunct in treating OHCA. It is unlikely that a CPR device will ever fully replace the need for manual compressions. However, if device compressions can be shown to be as safe and effective as manual compressions, then it could be used to assist providers when performing CPR. Therefore, there was a need for another randomized clinical trial comparing manual and integrated mechanical CPR, where a patient receives manual compressions while the mechanical device is deployed.
The randomized Circulation Improving Resuscitation Care (CIRC) Trial objective was to compare automated LDB-CPR integrated with manual CPR (iA-CPR) to high quality manual CPR (M-CPR), to determine equivalence, superiority, or inferiority in survival to hospital discharge after OHCA.
Section snippets
Methods
The CIRC methods and design including the statistical analysis plan have been previously published.13 CIRC was a randomized, controlled group sequential trial of adult OHCA of presumed cardiac origin conducted under exception from informed consent for emergency research and approved by the Institutional Review Boards (three US sites: Fox Valley Region, WI; Hillsborough County, FL; Houston, TX) or Ethics committee (two European sites: Vienna, Austria; Nijmegen, The Netherlands).13 Sites
Results
During the run-in phase data was collected for 621 patients. The first site began enrollment into the statistical inclusion phase on March 5, 2009. The equivalence stopping boundary was crossed at the 8th interim analysis and the last patient was enrolled on January 11, 2011. During the statistical inclusion phase, 9068 cardiac arrests occurred in the study communities, but 3987 did not meet the study inclusion criteria and 328 patients were missed for enrollment (Fig. 1). Post enrollment, 522
Discussion
The CIRC study demonstrated that iA-CPR is equivalent to high-quality M-CPR for survival to hospital discharge from OHCA of presumed cardiac origin. Neurologic outcome did not differ between strategies. There were slight differences between the unadjusted and adjusted OR for survival to hospital discharge. Adjustment for the interim analyses changed the OR from a small negative effect to a small positive effect. The reason for this is that the study was stopped when the iA-CPR arm had just
Authors’ contribution
LW oversaw development of the protocol and was responsible for the overall conduct of the trial. All authors contributed to protocol development. FS, RM, MB, PG, ML, DT, MW, DP, and CS oversaw data collection at each of the trial sites. JO oversaw the analysis of all electronic ECG files. AW, an academic statistician at Lancaster University, was responsible for the group sequential design and for conducting the primary and secondary statistical analyses. LW drafted the manuscript and all
Conflict of interest statement
UH is an employee of ZOLL which manufactures and sells the LDB device (AutoPulse). All other authors’ institutions received funding from ZOLL for their participation in the trial. The authors have no other relevant financial conflicts of interest to report.
Funding
This trial was funded by ZOLL Medical (the manufacturer of the study device), and all authors’ institutions received funding from ZOLL for their participation in the trial. ZOLL developed the CIRC trial protocol in consultation with the principal investigator, study investigators, staff at the data coordinating center, and the statistician (AW). Norwegian Center for Prehospital Emergency Care (NAKOS), Oslo University Hospital funded the PI during and after the study.
Acknowledgements
The authors would like to acknowledge the EMS providers who contributed to this study as well as other individuals who made this study possible. We would specifically like to thank the following people for their contributions to the project: CIRC management and operation: Trial manager Jeff Jensen, Trial coordinators Marcia Hefner, Colin Thomas; Central Data management: Brian Baker, Wave Engineering; Ronald Pirrallo MD, MHSA and Guy Gleisberg, BS, NR-EMT Medical College of Wisconsin. Fox Valley
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A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.03.005.
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Registration Name and Number: ClinicalTrials.gov Identifier: Circulation Improving Resuscitation Care (CIRC) NCT00597207.