Recreating the Feel of the Human Chest in a CPR Manikin via Programmable Pneumatic Damping

It is well known that the human chest exhibits a strong force displacement hysteresis during CPR, a stark contrast to the non hysteretic behavior of standard spring manikins. We hypothesize that individuals with experience performing CPR on humans would perceive a manikin with damping as more realistic and better for training. By analyzing data collected from chest compressions on real patients, we created a dynamic model that accounts for this hysteresis with a linear spring and a one-way variable damper, and we built a new high-fidelity manikin to enact the desired force displacement relationship. A linkage attached to the chest plate converts vertical compression motions to the horizontal displacement of a set of pneumatic dashpot pistons, sending a volume of air into and out of the manikin through a programmable valve. Position and pressure sensors allow a microcontroller to adjust the valve orifice so that the provided damping force closely follows the desired damping force throughout the compression cycle. Eight experienced CPR practitioners tested both the new manikin and an identical looking standard manikin; the manikin with damping received significantly higher ratings for haptic realism and perceived utility as a training tool

The Effect of Posture During CPR on Rescuer Muscular Fatigue Development and CPR Quality

The purpose of this study was to evaluate muscle fatigue and CPR quality over time, during four CPR positions. Twenty-one, CPR-certified participants performed six-minutes of CPR, on a training manikin, at four heights (KH, LH, FH, WH). EMG of sixteen muscles, kinematics of the manikin, and kinetic data at the hands were collected. The MPF identified that four, six, four, and nine muscles fatigued during KH, LH, FH, and WH, respectively. Furthermore, there was a linear decrease in CC force and CC depth over time, during all positions. The results indicated that rescuers should perform CPR below WH. Furthermore, as the TB produced the highest peak activation and fatigued within all CPR positions, it is recommended rescuers attempt to rest the TB during ventilations, if CPR is performed with two or more rescuers. Lastly, CPR feedback devices should be improved to detect full CC and display force vs. depth measurements