Apparatus for automatic delivery of chest compressions and ventilation to a patient. The apparatus includes a chest compressing device configured to deliver compression phases during which pressure is applied to compress the chest and decompression phases during which approximately zero pressure is applied to the chest a ventilator configured to deliver positive, negative, or approximately zero pressure to the airway; control circuitry and processor, wherein the circuitry and processor are configured to cause the chest compressing device to repeatedly deliver a set containing a plurality of systolic flow cycles, each systolic flow cycle including a systolic decompression phase and a systolic compression phase, and at least one diastolic flow cycle interspersed between sets of systolic flow cycles, each diastolic flow cycle including a diastolic decompression phase and a diastolic compression phase, wherein the diastolic decompression phase is substantially longer than the systolic decompression phase.

A method of processing a raw acceleration signal, measured by an accelerometer-based compression monitor, to produce an accurate and precise estimated actual depth of chest compressions. The raw acceleration signal is filtered during integration and then a moving average of past starting points estimates the actual current starting point. An estimated actual peak of the compression is then determined in a similar fashion. The estimated actual starting point is subtracted from the estimated actual peak to calculate the estimated actual depth of chest compressions. In addition, one or more reference sensors (such as an ECG noise sensor) may be used to help establish the starting points of compressions. The reference sensors may be used, either alone or in combination with other signal processing techniques, to enhance the accuracy and precision of the estimated actual depth of compressions.

Apparatus for automatic delivery of chest compressions and ventilation to a patient, the apparatus including: a chest compressing device configured to deliver compression phases during which pressure is applied to compress the chest and decompression phases during which approximately zero pressure is applied to the chest a ventilator configured to deliver positive, negative, or approximately zero pressure to the airway; control circuitry and processor, wherein the circuitry and processor are configured to cause the chest compressing device to repeatedly deliver a set containing a plurality of systolic flow cycles, each systolic flow cycle comprising a systolic decompression phase and a systolic compression phase, and at least one diastolic flow cycle interspersed between sets of systolic flow cycles, each diastolic flow cycle comprising a diastolic decompression phase and a diastolic compression phase, wherein the diastolic decompression phase is substantially longer than the systolic decompression phase.

Apparatus for automatic delivery of chest compressions and ventilation to a patient, the apparatus including: a chest compressing device configured to deliver compression phases during which pressure is applied to compress the chest and decompression phases during which approximately zero pressure is applied to the chest a ventilator configured to deliver positive, negative, or approximately zero pressure to the airway; control circuitry and processor, wherein the circuitry and processor are configured to cause the chest compressing device to repeatedly deliver a set containing a plurality of systolic flow cycles, each systolic flow cycle comprising a systolic decompression phase and a systolic compression phase, and at least one diastolic flow cycle interspersed between sets of systolic flow cycles, each diastolic flow cycle comprising a diastolic decompression phase and a diastolic compression phase, wherein the diastolic decompression phase is substantially longer than the systolic decompression phase.

A method of processing a raw acceleration signal, measured by an accelerometer-based compression monitor, to produce an accurate and precise estimated actual depth of chest compressions. The raw acceleration signal is filtered during integration and then a moving average of past starting points estimates the actual current starting point. An estimated actual peak of the compression is then determined in a similar fashion. The estimated actual starting point is subtracted from the estimated actual peak to calculate the estimated actual depth of chest compressions. In addition, one or more reference sensors (such as an ECG noise sensor) may be used to help establish the starting points of compressions. The reference sensors may be used, either alone or in combination with other signal processing techniques, to enhance the accuracy and precision of the estimated actual depth of compressions.