Method of determining depth of chest compressions during CPR

A method of estimating the actual depth of chest compressions during chest compressions, wherein the method comprises the steps of:

• providing an accelerometer capable of measuring the acceleration caused by chest compressions;
• performing compressions, wherein the accelerometer produces an acceleration signal corresponding to the acceleration of chest compressions;
• providing the acceleration signal to a first filter, said first filter producing a filtered acceleration signal;
• providing the filtered acceleration signal to a processor, said processor producing a velocity signal corresponding to the velocity of chest compressions upon integrating the filtered acceleration signal;
• providing the velocity signal to a second filter, said second filter producing a filtered velocity signal;
• providing the filtered velocity signal to the processor, said processor producing a chest depth signal corresponding to the depth of chest compressions upon integrating the filtered velocity signal;
• providing the chest depth signal to a baseline limiter, said baseline limiter producing a chest depth signal with a processed baseline component;
• providing the chest depth signal with a processed baseline component to a starting point detector, said starting point detector identifying the starting points of chest compressions, and further providing a starting point signal corresponding to the starting points of chest compressions to a means for combining signals;
• providing the chest depth signal with a processed baseline component to a peak limiter, said peak limiter producing a chest depth signal with a processed peak component;
• providing the chest depth signal with a processed peak component to a peak detector, said peak detector identifying the peaks of chest compressions corresponding to the maximum depths of compressions, and further providing a peak signal corresponding to the peaks of chest compressions to the means for combining signals;
• calculating the estimated actual depth of chest compressions by combining the starting point signal with the peak signal.

A method of estimating the actual depth of chest compressions during chest compressions, wherein the method comprises the steps of:

• providing a means for performing chest compressions on a patient;
• providing a sensor capable of measuring an ECG signal of the patient and providing an accelerometer capable of measuring the acceleration of chest compressions;
• performing chest compressions on the patient, wherein the accelerometer produces an acceleration signal corresponding to the acceleration of chest compressions;
• measuring the ECG signal of the patient, wherein the measured ECG signal comprises an actual component and a noise component, and wherein at least part of the noise component is caused by chest compressions;
• identifying the noise component of the ECG signal, wherein a starting point of a compression is identified by a change in the noise component of the ECG signal;
• calculating the estimated actual depth of compressions by double integrating the acceleration signal when the starting point of a compression has been identified.

A method of performing CPR on a patient, wherein the method comprises the steps of:

• providing an accelerometer capable of sensing accelerations caused by chest compressions;
• performing chest compressions, wherein the accelerometer measures an acceleration signal during chest compressions;
• double integrating the acceleration signal to produce a measured depth signal corresponding to the measured depth of chest compressions;
• calculating an autoregressive moving average of the measured compression depth signal;
• wherein the estimated actual depth of compressions comprises the autoregressive moving average of the measured compression depth signal;
• providing a means for ventilating the patient;
• and
• ventilating the patient during CPR.