Comparison of mechanical characteristics of the human and porcine chest during cardiopulmonary resuscitation

Abstract Background Most studies investigating cardiopulmonary resuscitation (CPR) interventions or functionality of mechanical CPR devices have been performed using porcine models. The purpose of this study was to identify differences between mechanical characteristics of the human and porcine chest during CPR. Material and methods CPR data of 90 cardiac arrest patients was compared to data of 14 porcine from two animal studies. Chest stiffness k and viscosity μ were calculated from acceleration and pressure data recorded using a Laerdal Heartstart 4000SP defibrillator during CPR. K and μ were calculated at chest compression depths of 15, 30 and 50mm for three different time periods. Results At a depth of 15mm porcine chest stiffness was comparable to human chest stiffness at the beginning of resuscitation (4.8 vs. 4.5N/mm) and clearly lower after 200 chest compressions (2.9 vs. 4.5N/mm) ( p p Conclusion In conclusion, human and porcine chest behave relatively similarly during CPR with respect to chest stiffness, but differences in chest viscosity at medium and deep chest compression depth should at least be kept in mind when extrapolating porcine results to humans.