Abstract 298: Evaluation of Physiological Feedback-Based CPR in a Swine Model of Cardiac Arrest
Introduction: Chest compressions (CC)s are given to cardiac arrest patients at a fixed depth and rate during cardiopulmonary resuscitation (CPR), regardless of patient chest size, patient age, or cardiac arrest etiology. Mechanical CC devices help automate CCs, but are still limited by their fixed rate and depth settings. We investigated the feasibility of a CC device to respond to physiologic signals during a cardiac arrest by changing CC rate and depth.
Methods: A custom-built chest compression device for CPR was built by linking a linear actuator with a SmartMotorTM and writing MATLAB® code to control the actuator. The device was tested in a swine model of cardiac arrest where 3 sixty-pound female swine were instrumented with Millar pressure catheters in the aorta, shocked into ventricular fibrillation, left untreated for 8 minutes, and then treated with our device. The physiologic signals we investigated were central arterial pressure (CAP) and quantitative electrocardiogram (QECG). Median slope (MS) of the ECG was used as the QECG measure. In each animal experiment, a specific algorithm was tailored to alter rate or depth based on either CAP or QECG. Two CAP and one QECG experiment were performed. Baseline levels of the physiologic signal were recorded and monitored after adjustments to CC rate and depth. Adjustments were only made when a pre-set physiologic “threshold” was not met and parameters were changed until the threshold was reached. After the physiologic threshold was met, CPR was stopped and a rescue shock attempted.
Results: In this early stage pilot study for the feasibility of feedback-based CPR, we observed that the device successfully responded to both CAP and QECG signals as CCs were adjusted independent of the user. In the two CAP experiments, baseline CAP increased about 10mmHg after adjustments were made and threshold reached. Similar observations were seen in the QECG experiment as MS increased by 50 units when using the threshold technique.
Conclusions: Our device is capable of delivering CCs with a broad range of rates and depths. Promising results were obtained in a swine model of cardiac arrest where rates and depths were adjusted in response to CAP and QECG feedback.
Author Disclosures: M. Sundermann: None. D. Salcido: None. A. Koller: None. J.J. Menegazzi: None.
- © 2014 by American Heart Association, Inc.