An Instrument for Measuring Force Vector and Frequency of CPR Compressions

Cardio-Pulmonary Resuscitation (CPR) is a technique that allows a CPR certified person to keep alive someone whose heartbeat and/or breathing has stopped. Through compressions applied to the thorax of the individual in need of help, one can maintain the blood flow and air intake until further help (and equipment) arrives. Training for CPR is performed using manikins that mimic a human torso. In this paper, we design an instrument for measuring the force vector (magnitude and direction) and frequency of CPR compressions applied during CPR training sessions, to help a trainer objectively evaluate the performance of trainees. Excessive/insufficient force or frequency of compressions will harm, not help, the person in need. So it is important for a trainer to measure these parameters. Our instrument uses the standard CPR manikin plus a Nintendo Wii Fit balance board, and is therefore practical and affordable. Our experiments conducted with real subjects show that our system can measure these parameters with a standard uncertainty of 1.96 N, 0.79 degrees, and 0.26 Hz, respectively for force, direction and frequency.