This patent application is assigned to
The following quote was obtained by the news editors from the background information supplied by the inventors: "Resuscitation can generally include clearing a patient's airway, assisting the patient's breathing, chest compressions, and defibrillation.
"Defibrillation (sometimes known as step D) can be performed with the use of an automatic external defibrillator (AED). Most automatic external defibrillators are actually semi-automatic external defibrillators (SAED), which require a clinician to press a start button, after which the defibrillator analyzes the patient's condition and provides a shock to the patient if the electrical rhythm is shockable and waits for user intervention before any subsequent shock. Fully automatic external defibrillators, on the other hand, do not wait for user intervention before applying subsequent shocks. As used below, automatic external defibrillators (AED) include semi-automatic external defibrillators (SAED).
"Both types of defibrillators typically provide an oral stand clear warning before the application of each shock, and then the clinician is expected to stand clear of the patient and may be required to press a button indicating that the clinician is standing clear of the patient. The controls for automatic external defibrillators are typically located on a resuscitation control box.
"AEDs are used typically by trained providers such as physicians, nurses, fire department personnel, and police officers. There might be one or two people at a given facility that has an AED who have been designated for defibrillation resuscitation before an ambulance service arrives. The availability of on-site AEDs along with rescuers trained to operate them is important because if the patient experiences a delay of more than 4 minutes before receiving a defibrillation shock the patient's chance of survival can drop dramatically. Many large cities and rural areas have low survival rates for defibrillation because the ambulance response time is slow, although many suburbs have higher survival rates because of the faster ambulance response time due to lack of traffic and availability of hospitals and advanced life support.
"Trained lay providers are a new group of AED operators, but they rarely have opportunities to defibrillate. For example, spouses of heart attack victims may become lay providers, but these lay providers can be easily intimidated by an AED during a medical emergency. Consequently, such lay providers can be reluctant to purchase AEDs, or might tend to wait for an ambulance to arrive rather than use an available AED, out of concern that the lay provider might do something wrong.
"There are many different kinds of heart rhythms, some of which are considered shockable and some of them are not. For example, a normal rhythm is considered non-shockable, and there are also many abnormal non-shockable rhythms. There are also some abnormal non-viable non-shockable, which means that the patient cannot remain alive with the rhythm, but yet applying shocks will not help convert the rhythm.
"As an example of a non-shockable rhythm, if a patient experiences asystole, the heart will not be beating and application of shocks will be ineffective. Pacing is recommended for asystole, and there are other things that an advanced life support team can do to assist such patient, such as the use of drugs. The job of the first responder is simply to keep the patient alive, through the use of CPR and possibly defibrillation, until an advanced life support team arrives. Bradycardias, during which the heart beats too slowly, are non-shockable and also possibly non-viable. If the patient is unconscious during bradycardia, it can be helpful to perform chest compressions until pacing becomes available. Electro-mechanical dissociation (EMD), in which there is electrical activity in the heart but it is not making the heart muscle contract, is non-shockable and non-viable, and would require CPR as a first response. Idio-ventricular rhythms, in which the normal electrical activity occurs in the ventricles but not the atria, can also be non-shockable and non-viable (usually, abnormal electrical patterns begin in the atria). Idio-ventricular rhythms typically result in slow heart rhythms of 30 or 40 beats per minute, often causing the patient to lose consciousness. The slow heart rhythm occurs because the ventricles ordinarily respond to the activity of the atria, but when the atria stop their electrical activity, a slower, backup rhythm occurs in the ventricles.
"The primary examples of shockable rhythms, for which a first responder should perform defibrillation, include ventricular fibrillation, ventricular tachycardia, and ventricular flutter.
"After using a defibrillator to apply one or more shocks to a patient who has a shockable electrical rhythm, the patient may nevertheless remain unconscious, in a shockable or non-shockable rhythm. The rescuer may then resort to chest compressions. As long as the patient remains unconscious, the rescuer can alternate between use of the defibrillator (for analyzing the electrical rhythm and possibly applying a shock) and performing cardio-pulmonary resuscitation (CPR).
"CPR generally involves a repeating pattern of five or fifteen chest compressions followed by a pause. CPR is generally ineffective against abnormal rhythms, but it does keep some level of blood flow going to the patient's vital organs until an advanced life support team arrives. It is difficult to perform CPR over an extended period of time. Certain studies have shown that over a course of minutes, rescuers tend to perform chest compressions with less-than-sufficient strength to cause an adequate supply of blood to flow to the brain. CPR prompting devices can assist a rescuer by prompting each chest compression and breath.
"PCT Patent Publication No. WO 99/24114, filed by
In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "In a first aspect, the invention features a resuscitation system for use by a rescuer for resuscitating a patient, comprising at least two high-voltage defibrillation electrodes, a first electrical unit comprising circuitry for providing resuscitation prompts to the rescuer, a second electrical unit separate from the first unit and comprising circuitry for providing defibrillation pulses to the electrodes, and circuitry for providing at least one electrical connection between the first and second units.
"Preferred implementations of this aspect of the invention may incorporate one or more of the following. The two electrodes and the first unit may be built into a defibrillation electrode pad assembly. The defibrillation electrodes may be detachable from the defibrillation electrode pad assembly. The first unit may be separate from the two electrodes, and may be connected to the two electrodes by one or more cables. The first unit may be capable of functioning and providing the resuscitation prompts without being electrically connected to the second unit. The first unit may comprise a source of electrical power and a processor. The first unit may have circuitry for monitoring at least one physiological parameter of the patient. The parameter may be an ECG signal. The resuscitation prompts may comprise CPR prompts. The circuitry for providing at least one electrical connection between the first and second units may comprise at least one cable. The circuitry for providing at least one electrical connection between the first and second units may comprise at least one wireless connection. The second unit may be connected directly to the defibrillation electrodes by one or more cables that carry the defibrillation pulses to the electrodes. The circuitry for providing at least one electrical connection between the first and second units may comprise at least one cable for delivering the defibrillation pulses to the first unit, from where they are delivered to the electrodes. The ECG signal may be detected using the defibrillation electrodes. The first unit may comprise a speaker for providing the resuscitation prompts. The resuscitation prompts may comprise spoken and visual prompts. The first unit may comprise a microphone and circuitry for storing sounds recorded during use of the unit. The defibrillation electrodes may be built into an electrode pad assembly and a handle for providing an upward lifting force on the assembly may be provided. The handle may comprise a flexible sheet material. The handle may comprise a substantially rigid material.
"In a second aspect, the invention features a resuscitation system for resuscitating a patient, comprising at least two electrical therapy electrodes adapted to be worn by the patient for extended periods of time, circuitry for monitoring the ECG of the patient, an activity sensor adapted to be worn by the patient and capable of providing an output from which the patient's current activity can be estimated, and at least one processor configured for estimating the patient's current activity by analyzing the output of the activity sensor, analyzing the ECG of the patient, and determining whether electrical therapy should be delivered to the electrodes.
"Preferred implementations of this aspect of the invention may incorporate one or more of the following. The processor may be configured for estimating whether the patient is moving. The activity sensor may comprise an accelerometer, and the processor may be configured for integrating the output of the accelerometer to provide an estimate of velocity and/or displacement. The processor may be configured to process the output of the activity sensor and use the result of the processing to modify at least one threshold in a technique used for determining a physiological status of patient. The physiological status may comprise determining a risk of impending heart attack or cardiac arrest. The resuscitation system may include a speaker for issuing spoken prompts to the patient, and the processor may decide on the nature of the spoken prompt based on the estimated current activity of the patient. The patient's current activity may comprise estimating the orientation of the patient. Estimating the orientation of the patient may comprise determining whether the patient lying on his back. The electrodes may be defibrillation electrodes and the electrical therapy may comprise a defibrillation pulse. The invention may further comprise an activity sensor adapted to be worn by the patient and capable of providing an output from which the patient's current activity can be estimated, and at least one processor configured for estimating the patient's current activity by analyzing the output of the activity sensor. The at least one processor may be located in the first unit. At least some of the resuscitation prompts delivered by the first unit may be dependent on the estimated current activity of the patient. The current activity may comprise whether the patient is lying on his back, and at least one resuscitation prompt issued when the patient is not on his back may be an instruction to roll the patient on their back prior to beginning CPR.
"In a third aspect, the invention features a resuscitation system for resuscitating a patient, comprising at least two electrical therapy electrodes adapted to be worn by the patient for extended periods of time, circuitry for monitoring the ECG of the patient, an activity sensor adapted to be worn by the patient and capable of providing an output from which the patient's current activity can be estimated, and at least one processor configured for estimating the patient's current activity by analyzing the output of the activity sensor, analyzing the ECG of the patient, and determining whether the patient has an elevated probability of cardiac arrest.
"Preferred implementations of this aspect of the invention may incorporate one or more of the following. The processor may be configured for determining whether the patient's current activity includes increased physical activity. The processor may be configured for determining an activity level parameter representative of the patient's activity level. The decision of an elevated probability of cardiac arrest may be based on the activity level parameter and a parameter may be derived from the patient's ECG. The decision of an elevated probability of cardiac arrest may be based on the activity level parameter and a measurement of blood pressure. The invention may further comprise the capability of delivering at least one test pulse through the electrodes at a time based, at least in part, on an estimate of the patient's current activity, wherein the test pulse is of a type configured to produce a ventricular premature beat (VPB). The time based on an estimate of the patient's current activity may be shortly after waking in the morning. Prior to delivering the test pulse, the system may issue a prompt to the patient requesting administration of the test pulse and the system may wait for the patient to indicate his consent to administration of the test pulse.
"Among the many advantages of the invention (some of which may be achieved only in some of its various aspects and implementations) are that the invention may permit wider distribution and availability of the first unit, which provides resuscitation prompting, than of the second unit, which provides defibrillation therapy. The first unit's relatively lower cost may make it possible for the first unit to be more widely distributed than the second unit. Wider distribution of the first unit may mean more successful rescues, as a patient can be stabilized and prepared for defibrillation using the first unit.
"The unit may be worn on a continuous basis by a person at higher risk of a heart attack such as someone who has recently undergone bypass surgery or one who has experienced a myocardial infarction. The early warning of a heightened risk of an impending cardiac arrest provided by the device will allow the wearer of the device to phone a physician or emergency service in advance of the actual cardiac arrest, thus reducing fatality rates of cardiac arrest by early prevention and treatment of the underlying physiological abnormalities rather than treating the consequences of the arrest. The activity sensor provides a means of determining whether or not the wearer of the device is awake or not, thereby providing an accurate way of providing voice prompts and physiological tests in synchrony with the wearer's daily schedule in a non-interfering manner. When used in conjunction with a communication link to medical providers such as an EMS system, the activity sensor also provides a means of determining the state of the victim, whether the victim is vertical or horizontal, and moving, thus potentially lowering false alarm rates and accuracy of diagnosis.
"The activity sensor may also be used to adjust the thresholds used for various alarms and heart attack risk detection methods. The wearer can activate a keying input on the device indicating chest pain, and in conjunction with the additional ECG, and activity sensor data, the device can more reliably calculate relative risk of impending heart attack or cardiac arrest and with a communication means, potentially contact emergency services directly without intervention of the wearer.
"Other features and advantages of the invention will be found in the detailed description, drawings, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
"FIG. 1 is a drawing of a defibrillation electrode pad according to the invention, positioned over the chest of a patient.
"FIG. 2 is a view of the front display panel of a resuscitation control box according to the invention that houses electronic circuitry and provides audible and visual prompting.
"FIG. 3 is a cross-sectional drawing of the defibrillation electrode pad of FIG. 1 taken along line 3-3.
"FIG. 4 is a cross-sectional drawing of the defibrillation pad of FIG. 1 taken along line 4-4.
"FIG. 5 is a circuit diagram illustrating the circuit interconnections between the defibrillation electrode pad of FIG. 1 and the resuscitation control box of FIG. 2.
"FIGS. 6A and 6B are a flowchart illustrating the initial routine of a resuscitation system according to the invention.
"FIGS. 7A, 7B, and 7C are a flowchart illustrating the 'circulation help' routine of the resuscitation system.
"FIG. 8 is a flowchart illustrating the 'breathing help' routine of the resuscitation system.
"FIGS. 9A and 9B are a flowchart illustrating the 'airway help' routine of the resuscitation system.
"FIG. 10 is a block diagram of the electronic circuitry of an alternative implementation.
"FIG. 11 is a drawing of the defibrillation electrode assembly of another alternative.
"FIGS. 12A-12C are diagrammatic views of three possible implementations of first and second units.
"FIGS. 13A and 13B are drawings of two alternative implementations of the electrode pad assembly in which a handle is provided for the rescuer."
URL and more information on this patent application, see: Freeman, Gary A.; Totman, Mark. Integrated Resuscitation. Filed
Keywords for this news article include: Therapy, Cardiology, Heart Attack, Cardio Device, Resuscitation, Cardiac Arrest, Medical Devices, Emergency Treatment,
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