CPR chest compression monitor and method of use

• US 7,074,199 B2
• Filed: 09/12/2001
• Issued: 07/11/2006
• Est. Priority Date: 11/09/1998
• Status: Expired due to Term

• Current Assignee: Johns Hopkins University
• Original Assignee: Revivant Corporation (Asahi Kasei Corporation)
• Inventors: Berger, Ronald D., Halperin, Henry R.
• Primary Examiner(s): Cronin, Stephen K.
• Assistant Examiner(s): Mathew, Fenn C.
• Application Number:
  US09/952,866
• Publication Number:
  US 20020055694A1
• Time in Patent Office: 1,763 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, 482/44, 482/51
• 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 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 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

a signaling mechanism, operably connected to the microprocessor, for indicating when the distance value is within the desired range;

wherein the distance value is determined solely from the acceleration signal.

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

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

converting, using a processor 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;

comparing, using the processor, the linear displacement signal to a set range; and

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

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

measuring, using a tilt sensor, an angular velocity signal of the compression monitor during the chest compressions;

converting, using the processor which is further electrically connected to the tilt sensor, the angular velocity signal into an angular displacement signal;

adjusting, using the processor, the linear displacement signal to an adjusted linear displacement signal to account for the angular displacement;

signaling, using the signaling mechanism, when the adjusted linear displacement signal is within the set range.

4. 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, wherein the displacement is determined solely from the acceleration signal;

a tilt compensator, operably connected to the accelerometer, comprising a tilt sensor mechanism for outputting a tilt compensation signal indicative of the extent of tilt of the accelerometer; and

a signaling mechanism, operably connected to the tilt compensation signal, for indicating when the tilt compensation signal is within the desired range.

5. A method for facilitating the effective 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;

comparing, using the processor, the chest compression displacement signal to a set range; and

signaling, using the signaling mechanism, when the chest compression displacement signal is within the set range.

6. The method of claim 5 comprising the further steps of:

measuring, using a tilt sensor operably connected to the processor, an angular acceleration signal of the compression monitor during chest compressions;

converting, using the processor, the angular acceleration signal into an angular displacement signal corresponding to the angular distance the chest of a patient is compressed;

wherein the processor accounts for the effects, on the angular displacement signal, of angular accelerations that are caused by forces other than those created by the administration of CPR;

adjusting, using the processor, the chest compression displacement signal to an adjusted chest compression displacement signal to account for the angular displacement;

signaling, using the signaling mechanism, when the adjusted chest compression displacement signal is within the set range.

7. The method of claim 6 comprising the further step of signaling, using the signaling mechanism, when the angular displacement signal is within a set range.