CPR chest compression monitor and method of use

• US 7,429,250 B2
• Filed: 07/11/2006
• Issued: 09/30/2008
• Est. Priority Date: 11/09/1998
• Status: Expired due to Fees

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Berger, Ronald D., Halperin, Henry R.
• Primary Examiner(s): Mathew; Fenn C
• Application Number:
  US11/456,841
• Publication Number:
  US 20060247560A1
• Time in Patent Office: 812 Days
• Field of Search: 601 41- 44, 601/104, 601/134, 733/790.1, 738/625.42, 733/790.3, 733/790.8, 600/587, 600/594, 434/262, 434/265
• US Class Current: 601/41
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/6825 Hand
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61B 5/721 using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61H 2201/5007 computer controlled
• CPC Class Codes: A61H 2201/5048 Audio interfaces, e.g. voice or music controlled
• CPC Class Codes: A61H 2201/5058 Sensors or detectors
• CPC Class Codes: A61H 2201/5064 Position sensors
• CPC Class Codes: A61H 2201/5071 Pressure sensors
• CPC Class Codes: A61H 2201/5084 Acceleration sensors
• CPC Class Codes: A61H 2230/04 Heartbeat characteristics, e.g. E.G.C., blood pressure modulation
• CPC Class Codes: A61H 2230/06 : Heartbeat rate
• CPC Class Codes: A61H 2230/855 : used as a control parameter for the apparatus
• CPC Class Codes: A61H 31/00 : Artificial respiration or heart stimulation, e.g. heart massage artificial respiration by treatment with gas or air, e.g. mouth-to-mouth respiration A61M16/00; applying electric currents by contact electrodes for stimulation, e.g. heart pace-makers A61N1/36 ; teaching or training models, demonstration models for medical purposes G09B23/288
• CPC Class Codes: A61H 31/005 : with feedback for the user
• CPC Class Codes: A61H 31/006 : Power driven
• CPC Class Codes: A61H 31/007 : Manual driven
• CPC Class Codes: A61M 16/00 : Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/10 : Preparation of respiratory gases or vapours
• CPC Class Codes: A61M 2230/06 : Heartbeat rate only
• CPC Class Codes: A61N 1/39044 : in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: G06F 2218/04 : Denoising
• CPC Class Codes: G09B 23/288 : for artificial respiration or heart massage

Abstract

Chest compressions are measured and prompted to facilitate the effective administration of CPR. A displacement detector produces a displacement indicative signal indicative of the displacement of the CPR recipient'"'"'s chest toward the recipient'"'"'s spine. A signaling mechanism provides chest compression indication signals directing a chest compression force being applied to the chest and a frequency of such compressions. An automated controller and an automated constricting device may be provided for applying CPR to the recipient in an automated fashion. The automated controller receives the chest compression indication signals from the signaling mechanism, and, in accordance with the chest compression indication signals, controls the force and frequency of constrictions. The system may be provided with a tilt compensator comprising a tilt sensor mechanism outputting a tilt compensation signal indicative of the extent of tilt of the device, and may be further provided with an adjuster for adjusting the distance value in accordance with the tilt compensation signal. An ECG signal processor may be provided which removes the CPR-induced artifact from a measured ECG signal_obtained during the administration of CPR.

Claims

1. A system for facilitating the administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a microprocessor being programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and compare the distance value to a desired range; and

said microprocessor being further programmed to output a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest;

wherein the distance value is determined solely from the acceleration signal; and

means for disposing the accelerometer in fixed relation to the recipient'"'"'s chest.

3. The system according to claim 1, further comprising:

a signaling mechanism operably connected to the processor, said microprocessor being further programmed to operate said signaling mechanism to indicate when the linear displacement signal is within a predetermined range.

5. The method according to claim 1, further comprising:

an automated constricting device and means for controlling said automated constricting device based on the signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

2. A method for facilitating the administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing an accelerometer and a means for disposing the accelerometer in fixed relation to a CPR recipient'"'"'s chest;

measuring, using the accelerometer, an acceleration signal of the compression monitor during chest compressions;

converting, using a microprocessor electrically connected to the accelerometer, the acceleration signal into a linear displacement signal indicative of the displacement of a CPR recipient'"'"'s chest caused by CPR, wherein the linear displacement signal is determined solely from the acceleration signal; and

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

4. The method according to claim 2, further comprising the steps of:

signaling, using a signaling mechanism operably connected to the processor, when the linear displacement signal is within a predetermined range.

6. The method according to claim 2, further comprising the steps of:

providing an automated constricting device and controlling said automated constricting device based on the signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

7. A method for facilitating the administration of cardiopulmonary resuscitation (CPR) on a patient by using a compression monitor to detect the depth of chest compressions while performing chest compressions and while the patient and the compression monitor are also subject to accelerations caused by forces other than those created by the administration of CPR, said method comprising the steps of:

providing a compression monitor comprising an accelerometer, a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR;

wherein the processor is programmed to account for the effects, on the chest compression displacement signal, of accelerations that are caused by forces other than those created by the administration of CPR, whereby the processor is capable of determining the chest compression displacement signal by processing only the acceleration signal;

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

8. The method according to claim 7, further comprising the steps of:

signaling, using a signaling mechanism operably connected to the processor, when the linear displacement signal is within a predetermined range.

9. The method according to claim 7, further comprising the steps of:

providing an automated constricting device and controlling said automated constricting device based on the signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

10. A system for facilitating the effective administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a housing for coupling the accelerometer to the chest; and

a microprocessor programmed to process the acceleration signal to determine the depth of chest compression and produce a compression signal indicative of the depth of compression of the patient'"'"'s chest, said microprocessor further programmed to calculate downward displacement of the chest using the acceleration signal without reference to a signal derived from a source which is not coupled to the chest.

12. The system of claim 10 further comprising:

a signaling mechanism, said signaling mechanism operable to produce a signal indicative of the displacement of the chest and operably connected to the microprocessor, wherein the microprocessor is further programmed to operate the signaling mechanism to indicate when the displacement value of the chest is within a desired range.

11. A system for facilitating the effective administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a housing for holding the accelerometer in fixed relationship to the chest as it moves in response to CPR compressions;

a microprocessor programmed to process the acceleration signal to determine the depth of chest compression and produce a compression signal indicative of the depth of compression of the patient'"'"'s chest, said microprocessor further programmed to calculate downward displacement of the chest using the acceleration signal, without reference to a signal derived from a source not held in fixed relationship to the chest.

13. The system of claim 11 further comprising:

a signaling mechanism, said signaling mechanism operable to produce a signal indicative of the displacement of the chest and operably connected to the microprocessor, wherein the microprocessor is further programmed to operate the signaling mechanism to indicate when the displacement value of the chest is within a desired range.

14. A method for facilitating the effective administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing a compression monitor comprising an accelerometer, said accelerometer housed in a module adapted to be coupled to the chest during chest compression, and a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

coupling the module to the chest during CPR compressions;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR, without reference to a signal derived from a source which is not coupled to the chest;

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

16. The method of claim 14 further comprising the step of measuring a force resulting from a CPR compression using a force transducer.

15. A method for facilitating the effective administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing a compression monitor comprising an accelerometer, said accelerometer housed in a module adapted to be held in fixed relationship to the chest during chest compression, and a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR, without reference to a signal derived from a source which is not held in fixed relationship to the chest;

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

17. The method of claim 15 further comprising the step of measuring a force resulting from a CPR compression using a force transducer.

18. A system for facilitating the effective administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a housing for holding the accelerometer in fixed relationship to the chest as it moves in response to CPR compressions;

a force transducer for producing a force signal indicative of a force resulting from a CPR compression; and

a microprocessor programmed to process the acceleration signal to determine the depth of chest compression and produce a compression signal indicative of the depth of compression of the patient'"'"'s chest, said microprocessor further programmed to determine the start of a compression without reference to a signal derived from a source other than the accelerometer or force transducer, and thereafter calculate downward displacement of the chest using the acceleration signal;

said microprocessor further programmed to output a compression signal.

21. The system of claim 18 further comprising:

a signaling mechanism, said signaling mechanism operable to produce a signal indicative of the displacement of the chest and operably connected to the microprocessor, wherein the microprocessor is further programmed to operate the signaling mechanism to indicate when the displacement value of the chest is within a desired range.

19. A system for facilitating the effective administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a housing for coupling the accelerometer to the chest;

a force transducer for producing a force signal indicative of a force resulting from a CPR compression; and

a microprocessor programmed to process the acceleration signal to determine the depth of chest compression and produce a compression signal indicative of the depth of compression of the patient'"'"'s chest, said microprocessor further programmed to determine the start of a compression without reference to a signal derived from a source which is not coupled to the chest, and thereafter calculate downward displacement of the chest using the acceleration signal.

22. The system of claim 19 further comprising:

a signaling mechanism, said signaling mechanism operable to produce a signal indicative of the displacement of the chest and operably connected to the microprocessor, wherein the microprocessor is further programmed to operate the signaling mechanism to indicate when the displacement value of the chest is within a desired range.

20. A system for facilitating the effective administration of cardiopulmonary resuscitation (CPR), said system comprising:

an accelerometer for producing an acceleration signal indicative of the displacement of a CPR recipient'"'"'s chest;

a housing for holding the accelerometer in fixed relationship to the chest as it moves in response to CPR compressions;

a force transducer for producing a force signal indicative of a force resulting from a CPR compression; and

a microprocessor programmed to process the acceleration signal to determine the depth of chest compression and produce a compression signal indicative of the depth of compression of the patient'"'"'s chest, said microprocessor further programmed to determine the start of a compression without reference to a signal derived from a source not held in fixed relationship to the chest and thereafter calculate downward displacement of the chest using the acceleration signal.

23. The system of claim 20 further comprising:

a signaling mechanism, said signaling mechanism operable to produce a signal indicative of the displacement of the chest and operably connected to the microprocessor, wherein the microprocessor is further programmed to operate the signaling mechanism to indicate when the displacement value of the chest is within a desired range.

24. A method for facilitating the effective administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing a compression monitor comprising an accelerometer, said accelerometer housed in a module adapted to be held in fixed relationship to the chest during chest compression, and a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

measuring a force resulting from a CPR compression and generating a force signal;

determining, using the processor, the start of a compression without reference to a signal derived from a source other than the accelerometer or force transducer

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR, without reference to a signal other than the acceleration signal or force signal; and

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

27. The method of claim 24 wherein the step of measuring a force resulting from a CPR compression further comprises measuring said using a force transducer.

25. A method for facilitating the effective administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing a compression monitor comprising an accelerometer, said accelerometer housed in a module adapted to be coupled to the chest during chest compression, and a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

coupling the module to the chest during CPR compressions;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

measuring a force resulting from a CPR compression;

determining the start of a compression without reference to a signal derived from a source which is not coupled to the chest;

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR, without reference to a signal derived from a source which is not coupled to the chest; and

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

28. The method of claim 25 wherein the step of measuring a force resulting from a CPR compression further comprises measuring said using a force transducer.

26. A method for facilitating the effective administration of cardiopulmonary resuscitation (CPR) using a compression monitor, said method comprising:

providing a compression monitor comprising an accelerometer, said accelerometer housed in a module adapted to be held in fixed relationship to the chest during chest compression, and a microprocessor operably connected to the accelerometer, said microprocessor programmed to convert the acceleration signal into a distance value indicative of the displacement of the CPR recipient'"'"'s chest caused by CPR and programmed to compare the distance value to a set range, and a signaling mechanism operably connected to the microprocessor, said signaling mechanism for indicating when the distance value is within the desired range;

measuring, using the accelerometer, an acceleration signal generated by the compression monitor during chest compressions;

measuring a force resulting from a CPR compression;

determining the start of a compression without reference to a signal derived from a source which is not held in fixed relationship to the chest;

converting, using the processor, the acceleration signal into a chest compression displacement signal corresponding to the distance the chest is compressed by the administration of CPR, without reference to a signal derived from a source which is not held in fixed relationship to the chest; and

providing a signal corresponding to the distance value indicative of the displacement of the CPR recipient'"'"'s chest.

29. The method of claim 26 wherein the step of measuring a force resulting from a CPR compression further comprises measuring said using a force transducer.