System for measuring and analyzing cardio-pulmonary-resuscitation (CPR) parameters for use with and by an external defibrillator (AED) or a training defibrillator

• US 6,351,671 B1
• Filed: 12/13/1999
• Issued: 02/26/2002
• Est. Priority Date: 12/11/1998
• Status: Expired due to Term

• Current Assignee: Laerdal Medical AS (Laerdal Medical Corporation)
• Original Assignee: Laerdal Medical AS (Laerdal Medical Corporation)
• Inventors: Eikeland, Harald, Myklebust, Helge, Eftestøl, Trygve
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Oropeza, Frances P.
• Application Number:
  US09/460,240
• Time in Patent Office: 806 Days
• Field of Search: 434/262, 434/265, 607/5, 607/6, 607/8, 607/142
• US Class Current: 607/5
• 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 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/28 for electrocardiography [ECG]
• CPC Class Codes: A61N 1/39044 in combination with cardiopulmonary resuscitation [CPR] therapy
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

A system for measuring and analyzing CPR parameters for use with and by an external defibrillator, where a pressure sensitive electrode is connected to a defibrillator, in addition to the standard electrodes of the defibrillator. The information from the pressure sensitive electrode, together with information derived from modulation of the impedance of the thorax, measured by the defibrillator, describes the quality of the CPR performed, and is used to generate voice messages that increase the quality and the effectiveness of the CPR. The defibrillator may in addition be equipped with a transmission device that sets up a radio connection with an emergency center. The emergency center is equipped with a display unit that shows the activities at the resuscitation site. In addition to the data transfer link, a speech connection is set up via a microphone and a speaker on the resuscitation site and a microphone and auditory unit at the emergency center, in order to allow an operator at the emergency center to intervene and direct the attempt at resuscitation during the critical phases following the electrical shocks. During training and practice, the defibrillator or the training defibrillator will receive information from sensors placed in the manikin regarding the CPR performance, and will then use this information to give instructions.

Claims

1. A system for measuring and analyzing CPR parameters for use with and by an external defibrillator or a training defibrillator (collectively hereinafter, “

defibrillator”

), the system comprising;

a plurality of sensors connected with the defibrillator, the sensors providing information regarding chest compressions and lung inflations;

a system processor communicating with the sensors, wherein the system processor compares the information regarding chest compressions and lung inflations with corresponding parameters that describe guidelines for recommended CPR; and

a sound output device connected with the system processor, the system processor driving the sound output device to generate voice messages in response to any deviation between the information regarding chest compressions and lung inflations detected by the sensors and the corresponding parameters that describe guidelines for recommended CPR.

2. A system according to claim 1, further comprising a transmission device that establishes a radio link to an emergency center when the defibrillator is activated in a normal mode, the transmission device effecting a data link that transmits the information regarding chest compressions and lung inflations detected by the sensors and a speech connection link via a microphone and a speaker, thereby permitting an operator at the emergency center to intervene and direct a resuscitation attempt during critical phases following electrical shocks delivered by the defibrillator.

3. A system according to claim 1, further comprising a manikin for operation of the defibrillator in a training mode, the manikin comprising manikin sensors that detect secondary information regarding chest compressions and lung inflations and a manikin sensor processor communicating with the manikin sensors, the manikin sensor processor communicating with the system processor to simulate a connection with an emergency center.

4. A system according to claim 1, wherein the plurality of sensors comprise a pressure sensitive electrode functioning as a force transducer for detecting chest compressions, a top portion of the pressure sensitive electrode being provided with printed electrode placement instructions.

5. A system according to claim 4, wherein the pressure sensitive electrode forms a signal reference for the defibrillator'"'"'s measurement of an ECG signal.

6. A system according to claim 1, wherein the plurality of sensors comprise an impedance measuring system, and wherein the defibrillator measures a modulation of a voltage generated between electrodes of the defibrillator, the modulation being caused by changes in impedance due to lung inflations and chest compressions.

7. A system according to claim 6, wherein the impedance measurement system communicates an impedance signal to the system processor for determining inflation occurrences, inflation time, occurrences of chest compressions and chest compression rate.

8. A system according to claim 6, wherein an alternating current with a frequency of between 0.1 and 100 kHz is used as an excitation signal.

9. A system according to claim 8, wherein the frequency of the alternating current is 30 kHz.

10. A system according to claim 1, wherein the system processor calculates an ECG signal median frequency and spectral flatness based on the information regarding chest compressions and lung inflations detected by the sensors and combines the ECG signal median frequency and spectral flatness into a vector value, the system processor comparing the vector value to a threshold value, wherein the system processor provides an instruction to proceed with CPR if the vector value is below the threshold and provides an instruction to proceed with defibrillation if the vector value is above the threshold.

11. A system for measuring and analyzing CPR parameters for use with and by an external defibrillator or a training defibrillator (collectively hereinafter, “

defibrillator”

), the system comprising;

a sound output device;

an impedance modulation sensor connected with the defibrillator, the impedance modulation sensor providing a signal reflecting chest compression, chest compression force, chest inflation and chest inflation time; and

a processor communicating with the impedance modulation sensor, the processor determining chest compression, chest compression force, chest inflation and chest inflation time based on the signal from the impedance modulation sensor and comparing with corresponding parameters that describe guidelines for recommended CPR, wherein the processor drives the sound output device to generate voice messages in response to any deviation between chest compression, chest compression force, chest inflation and chest inflation time and the corresponding parameters that describe guidelines for recommended CPR.

12. A method of measuring and analyzing CPR parameters for use with and by an external defibrillator or a training defibrillator (collectively hereinafter, “

defibrillator”

), the method comprising;

detecting an impedance modulation across electrodes of the defibrillator and providing a signal reflecting chest compression, chest compression force, chest inflation and chest inflation time;

determining chest compression, chest compression force, chest inflation and chest inflation time based on the signal;

comparing the chest compression, chest compression force, chest inflation and chest inflation time with corresponding parameters that describe guidelines for recommended CPR; and

generating voice messages in response to any deviation between chest compression, chest compression force, chest inflation and chest inflation time and the corresponding parameters that describe guidelines for recommended CPR.