Design of the circulation improving resuscitation care (CIRC) trial: A new state of the art design for out-of-hospital cardiac arrest research

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Purpose: Mechanical chest compression devices, such as the AutoPulse®, have been developed to overcome problems associated with manual CPR (M-CPR). Some animal and human studies have shown that AutoPulse CPR improves hemodynamic parameters over M-CPR. However, human studies conducted in the prehospital setting have generated conflicting results as to the AutoPulse's efficacy in improving survival. The Circulation Improving Resuscitation Care (CIRC) Trial was designed to evaluate the effectiveness of integrated AutoPulse-CPR (iA-CPR) in a randomized controlled trial that addresses methodological issues that may have influenced the results of previous studies. Methods: This paper describes the methodology of the CIRC trial. Results Unlike previous trials the CIRC trial studies iA-CPR where emphasis is placed on reducing “hands off” time, and subjects receive M-CPR until the device is applied. The trial has 6 unique features: (1) A standardized deployment strategy with training provided to all EMS providers and continuous monitoring of protocol compliance. (2) A simulation study conducted to document provider compliance with the trial protocol and quality of CPR before starting the statistical inclusion phase of the study. (3) Three distinct study phases (in-field training, run-in, and statistical inclusion) to minimize the Hawthorne effect and other biases. (4) Monitoring of the CPR process using transthoracic impedance data and/or accelerometer data. (5) Randomization at the patient level after the decision to resuscitate is made. (6) Group sequential double triangular test statistics with pre-planned interim analyses to ensure the study question is answered. Conclusion: In the design of the CIRC trial efforts have been made to employ a suitable methodology to test the effectiveness and safety of iA-CPR compared to M-CPR. This unique large multicenter study will contribute to the science of the treatment of out-of-hospital cardiac arrest as well as to the design of future trials.