CPR chest compression system with tonometric input and feedback

Patent metadata

Field	Value
Publication number	US-10596064-B2
Application number	US-201514659612-A
Country	US
Kind code	B2
Filing date	Mar 16, 2015
Priority date	Mar 18, 2014
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A CPR chest compression system which uses tonometric data as feedback for control of chest compression device.

First claim

We claim:

1. A system for providing CPR (cardiopulmonary resuscitation) compressions on a cardiac arrest victim, said system comprising:
a chest compressor comprising a motor within a housing, the chest compressor configured to repetitively compress the chest of the cardiac arrest victim and generate compression-induced pulse pressure waves;
a tonometric sensor operable to detect the compression-induced pulse waves and produce pulse wave signals corresponding to each of the compression-induced pulse pressure waves;
at least one processor configured to:
control the chest compressor to generate a plurality of test chest compression sets comprised of chest compression parameters, wherein each test compression set includes at least one modified chest compression parameter, wherein the at least one modified chest compression parameter affects one or more waveform features of the compression induced pulse waves, the one or more waveform features including: a pseudo-reflective notch, and at least one of: a systolic pressure time integral (SPTI) value, a diastolic pressure time integral (DPTI) value, and a shelf;
receive the pulse wave signals and determine a one or more waveform for each of the pulse wave signals, and further identify the one or more waveform features of the pulse pressure waveforms;
identify which of the test compression sets resulted in the received pulse pressure waveforms having the one or more waveform features comprising the pseudo-reflective notch,
determine which of the identified test compression sets resulted in improved compression-induced blood flow based on at least one of: the SPTI value, DPTI value, and the shelf; and
operate the chest compressor according to the determined test compression sets that resulted in the improved compression-induced blood flow.

2. The system of claim 1 , wherein the tonometric sensor is adapted to be placed on a peripheral location of the cardiac arrest victim to:
detect the compression-induced pulse waves at a peripheral artery of the cardiac arrest victim,
produce a peripheral pulse wave signal corresponding to the compression-induced pulse waves detected at the peripheral location, and
wherein the at least one processor is configured to determine the pulse pressure waveform from the peripheral pulse wave signal.

3. The system of claim 2 , wherein the pulse pressure waveform determined from the peripheral pulse wave signal is an estimated aortic pulse pressure waveform obtained by applying a transfer function to the peripheral pulse wave signal.

4. The system of claim 1 , wherein at least one of the one or more waveform features includes a pressure time integral of the pulse pressure waveform.

5. The system of claim 4 , wherein the pressure time integral is a CPR total pressure time integral (TPTI) associated with an entire compression cycle of the chest compressor.

6. The system of claim 1 , wherein the chest compression parameters include at least one of: compression depth, a compression rate (cpm), a compression rise time, a compression hold time, and a release velocity.

7. The system of claim 1 , wherein the tonometric sensor comprises an array of pressure sensors disposed on a flexible substrate, where said flexible substrate is adapted for secure placement over a peripheral artery of the cardiac arrest victim, and the at least one processor is operable to receive signals from the array of pressure sensors and analyze those signals to determine a pulse pressure waveform of the peripheral artery.

8. The system of claim 1 , wherein at least one of the one or more waveform features includes a rising edge of a peak pressure of the pulse pressure waveform.

9. The system of claim 1 , wherein the at least one processor is further configured to determine which of the test compression sets resulted in a largest SPTI value, which is indicative of the improved compression-induced blood flow.

10. The system of claim 1 , wherein the at least one processor is further configured to determine which of the test compression sets resulted in a largest DPTI value, which is indicative of the improved compression-induced blood flow.

11. The system of claim 1 , wherein the at least one processor is further configured to determine which of the test compression sets resulted in a largest peak pressure value, which is indicative of the improved compression-induced blood flow.

12. The system of claim 1 , wherein the at least one processor is further configured to determine which of the identified test compression sets resulted in an appearance of the shelf following the pseudo-reflective notch, which is indicative of the improved compression-induced blood flow.

13. The system of claim 1 , wherein the one or more waveform features comprises an augmentation index, which is a calculated difference between two peaks.

14. The system of claim 13 , wherein the at least one processor is further configured to determine which of the identified test compression sets resulted in a largest augmentation index, which is indicative of the optimum compression-induced blood flow.

15. A method for providing CPR compressions on a cardiac arrest victim, said method comprising the steps of:
performing chest compressions on the cardiac arrest victim with a chest compressor to generate compression-induced pulse pressure waves, the chest compressor comprising a motor within a housing;
wherein performing the chest compressions includes performing a plurality of test chest compressions sets comprised of chest compression parameters, wherein each test compression set implements at least one modified chest compression parameter, the at least one modified chest compression parameters affecting one or more waveform features of the compression induced pulse waves, the one or more waveform features including: a pseudo-reflective notch, and at least one of: a systolic pressure time integral (SPTI) value, a diastolic pressure time integral (DPTI) value, and a shelf;

obtaining the compression-induced pulse pressure waveforms and generating pulse wave signals corresponding to each of the obtained compression-induced pulse waves;
identifying at least one feature of the compression-induced pulse pressure waveforms;
identifying which of the test compression sets resulted in received pulse pressure waveforms having the one or more waveform features comprising the pseudo-reflective notch;
determining which of the identified test compression sets resulted in improved compression-induced blood flow based on at least one of: the SPTI value, DPTI value, and the shelf; and
performing chest compressions according to the determined test compression sets that resulted in the improved compression induced blood flow.

16. The method of claim 15 , wherein the pulse pressure waveform is an estimated aortic pulse pressure waveform derived from a measured peripheral pulse pressure waveform.

17. The method of claim 15 , further comprising repeating the steps of re-identifying which of the test compression sets resulted in received pulse pressure waveforms having the pseudo-reflective inflection point and re-determining which of the identified test compression sets resulted in the improved compression-induced blood flow based on at least one of: the SPTI value, DPTI value, and the shelf; and
thereafter performing chest compressions according to the re-determined test compression sets that resulted in the chest compression parameters determined to have the improved compression induced blood flow.

18. The method of claim 15 , wherein the chest compression parameters in

Assignees

• Zoll Medical Corp

Inventors

• Kaufman Christopher L
• Freeman Gary A

Classifications

• A61H2201/1215

  Rotary drive · CPC title

• A61H2201/5046

  Touch screens · CPC title

• A61H2230/045

  used as a control parameter for the apparatus · CPC title

• A61H2201/5007

  computer controlled · CPC title

• A61H31/006

  Power driven · CPC title