Patent ID: 8532765

Claim:
A CPR therapy system comprising: a CPR coaching device operable to coach a rescuer in administering CPR to a patient, the CPR coaching device having a housing that includes an upper portion and a lower portion, the upper portion configured for placement of at least one of the rescuer's hands for delivery of chest compression force to the patient and the lower portion configured to be placed against the patient's chest, the CPR coaching device further including an accelerometer sensor responsive to the chest compression force which produces an acceleration signal, a force sensor responsive to the chest compression force which produces a force signal, and wherein the CPR therapy system further includes a processor responsive to the acceleration signal and the force signal, wherein the processor compares the two signals and reduces the effect of external motion not caused by the chest compression force on the CPR coaching device and the patient, wherein the processor is further responsive to the acceleration signal to doubly integrate the acceleration signal to produce a measure of chest compression depth, wherein the processor is operable to assess the reliability of the measure of chest compression depth, wherein the comparison further comprises correlation of the measure of chest compression depth and the force signal, wherein, when the correlation of the depth measure and the force signal is relatively low, the depth measure is assessed as being unreliable and a previously determined relationship between force and depth is utilized as a measure of chest compression depth.