Development and evaluation of a mechanical chest compression device for standardized rodent cardiopulmonary resuscitation

Small animal models are indispensable in cardiopulmonary resuscitation (CPR) research. High-quality CPR, characterized by consistent chest compression rate, depth, and positioning is crucial for survival. However, achieving standardization in manual high-frequency chest compressions in small animal models remains technically challenging. This study evaluated the reproducibility of manual chest compressions and introduced a novel mechanical chest compression device (MCD) designed to improve consistency in rodent experiments. In an in vitro setup, manual compressions were performed by ten participants at target rates ranging from 100 to 260 bpm, guided by a metronome. Compressions performed on a fluid-filled polymer reservoir were analyzed for the compression rate, variability, and time within a ± 10% target range. A color indicator was used to assess the variability of the compression point. A small animal MCD was designed and tested under the same conditions. In vivo, 5 Sprague-Dawley rats underwent 5 min of electrically induced normothermic cardiac arrest followed by 8 min of external chest compressions using the MCD. Obtained data was compared to the in vitro results. A total of 21,650 manual and 20,098 mechanical compressions were analyzed. At 200 bpm, chest compressions using the MCD were significantly more precise (201 ± 1.2 bpm) than manual compressions (218 ± 21 bpm, p < 0.001) with a significant reduced compression point variability (1.7 ± 0.1 cm² vs. 10.8 ± 3.1 cm², p < 0.001). Manual compressions maintained target rate in 58.8% of time compared to 100% for the MCD. In vivo testing confirmed these findings with chest compressions remaining within the target range 100% of the time and showing minimal rate variability (1.8 ± 1.7 bpm). These results highlight the limitations of manual chest compressions and demonstrate the potential of the MCD to enhance standardization and reproducibility in rodent CPR research.