Patent Application
20060058848
This invention relates generally to devices for providing therapy to a patient in a cardiac emergency, and more specifically to portable, automated external defibrillators having a user interface for providing visual and aural instructions for performing emergency cardiopulmonary resuscitation and defibrillation therapy.
AEDs have become widely accepted as an emergency device to be used by those persons who are typically first to arrive at the scene of a cardiac medical emergency, including not only professional medical care providers such as medical technicians (EMTs), but also firefighters, police and the public (hereinafter collectively referred to as “first responders”). For a patient in ventricular fibrillation, a first responder equipped with an AED will have a greater likelihood of successfully treating the patient than those who arrive later at the scene.
An AED designed for first responder use would therefore improve the overall success rate of treating cardiac arrest patients.
Because the probability of surviving a cardiac arrest depends on the speed with which appropriate medical care is provided to the patient, the American Heart Association (AHA) promotes the following “Chain of Survival” guidelines:
(1) Early access to emergency medical service (EMS), such as by activating an emergency response system;
(2) Early CPR initiated by a rescuer to help the patient survive until more advanced care arrives;
(3) Early defibrillation; and
(4) Early application of advanced cardiac life support (ACLS), such as airway management, drugs, etc.
With the exception of item number 4, all of the above guidelines can be performed by a first responder with minimal or no training, if provided with sufficient instruction while at the scene.
Even if the first responder does have some basic training in device operation and cardiopulmonary resuscitation (CPR), he or she may forget this basic training during the stress of reacting to a cardiac arrest. With wider deployment of AEDs in homes and public venues, the minimally trained or even untrained use of defibrillation devices will increase.
Consequently, a defibrillator is needed which is capable of successfully directing precise instructions to a first responder with minimal or no training through a cardiorespiratory event, i.e., CPR as well as AED device operation, by use of visual and aural instructions, and also which is capable of adapting its operation to input received from the first responder.
In a first aspect of an embodiment of the invention includes a device capable of providing a user with instructions for administering CPR. This device includes a user input mechanism and a processing unit coupled to the user input mechanism which directs the device to follow one of a first and a second sequence of steps depending on the user's input.
In another aspect, the device further includes an output device coupled to the processing unit for communicating prompts to the user, and the user's input is an input in response to a prompt.
In another aspect, the prompt is a request for the user to input information on an aspect of the patient's condition.
In still another aspect, the processing unit commands the device to perform the first sequence if the user does not input a response to the prompt.
In still another aspect, the device further includes electrodes which sense the patient's ECG signal, and one of the first and second sequences includes a prompt for analysis of the patient's ECG.
In still another aspect, the device includes a display screen and the user input mechanism includes a hardware button with a soft key on the display screen.
In still another aspect, the prompt is a query of whether a given action has been performed.
In another embodiment of the invention, a defibrillator capable of providing a user with instructions for administering defibrillation therapy includes a user input mechanism; a defibrillation therapy delivery circuit; a processing unit coupled to the user input mechanism and the defibrillation therapy delivery circuit which directs the device to follow one of a first and a second sequence of steps depending on the user's input; and an output device coupled to the processing unit for communicating prompts to the user.
In another aspect, the user's input is in response to a prompt.
In another aspect, the prompt is a request for the user to input information on an aspect of the patient's condition.
In another aspect, the defibrillator further includes electrodes which sense the patient's ECG signal, and one of the first and second sequences includes a prompt for analysis of the patient's ECG.
In another aspect, the defibrillator includes a display screen and the user input mechanism includes a hardware button with a soft key on the display screen.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
Additional buttons 13, 15 are provided immediately adjacent the display 14 to enable the user to input responses or information as will be described in more detail below. These are hardware buttons are associated with soft keys 17, 19 which appear on the display 14 to indicate to the user that input function served by the associated button at a given point in time. Although two such soft-keyed buttons have been illustrated, it will be understood that any other number of soft-keyed buttons may be provided.
Now that the overall design of an AED capable of providing both visual and aural CPR and defibrillation instructions has been discussed, several key AED components will be discussed in more detail. However, since the components of both AED 10 and AED 10′ are essentially the same, the description of these components will be made with reference to AED 10 as depicted in
As shown in more detail in
During defibrillation operation, the microprocessor 24 analyzes an electrocardiogram (ECG) of a patient using an automatic heart rhythm detection algorithm also stored in memory 20 to identify whether the patient is experiencing a shockable heart rhythm, such as ventricular fibrillation. The detection algorithm executed by the microprocessor 24 in the embodiment of the present invention described herein is similar to that used in the LIFEPAK® 500 defibrillator provided by Medtronic Emergency Response Systems Inc. of Redmond, Wash. Other known heart rhythm detection algorithms may also be used without departing from the scope of the present invention, such as those algorithms designed to comply with standards promulgated by the Association for the Advancement of Medical Instruments (AAMI). The ECG signals analyzed by the detection algorithm are collected by the electrode 16 and passed through a monitor circuit 28 to an analog-to-digital converter 26. The analog-to-digital converter 26 then passes the digitized signals to microprocessor 24. If the microprocessor 24 detects a shockable rhythm, the microprocessor causes a charging circuit 30 to generate a current causing a storage capacitor (not shown) to charge in preparation for delivery of a defibrillation pulse. When the capacitor is fully charged, and delivery of the defibrillation pulse initiated, a discharge circuit 32 coupled to the microprocessor 24 and charge circuit 30 discharges the defibrillation pulse to the electrodes 16 for application of the defibrillation pulse to the patient.
In accordance with the illustrated embodiments of the present invention, the AED 10 will provide visual and aural instructions to the rescuer via the display 14 and the speaker 18, respectively, advising application of a defibrillation pulse, in which case the rescuer would press a shock button 11 to deliver the defibrillation pulse. However, in another embodiment of the present invention, the AED will automatically apply a defibrillation pulse to the patient if the patient is experiencing ventricular fibrillation, without the rescuer's intervention.
Although the above describes the application of defibrillation therapy to a patient by the AED 10, the AED in an embodiment of the present invention actually provides the rescuer with an intuitive user interface for administering visual and aural instructions necessary for operating the defibrillator to provide defibrillation therapy, as well as instructions for administering CPR. The visual instructions may include inter alia animated or graphic illustrations that flash, move or remain static, textual prompts, light emissions, etc, while the aural instructions may include, inter alia, verbal prompts audible tones, etc. On a macro level, the user interface can be considered to include the user interface program 22, the display 14 or any other visual output device, generator or mechanism, and the speaker 18 or any other aural output device, generator or mechanism. The user interface of the present invention may also include various user input devices or mechanisms, e.g., shock button 11, start button 12, hardware buttons 13, 15 associated with soft keys 17, 19 on the display 14, soft buttons on a touch-sensitive display, or voice recognition for allowing the rescuer to input information and/or commands. Since the visual and aural output devices, i.e., display 14 and speaker 18, have already been described, the user interface program 22 of the present invention will be described in more detail in connection with
The logic begins in
In addition to providing the visual and verbal instructions to check the patient's responsiveness, in the
Accordingly, in a decision block 106, the user interface program determines if the rescuer has elected to continue to the next instruction. In accordance with the present invention, the rescuer may continue to the next instruction, and hence, effect the sequence of instructions generated by the user interface program 22 by pressing the appropriate button 13 (or, in an embodiment without soft keyed buttons like that of
It will be appreciated by those of ordinary skill in the art that the user interface program 22 may provide the rescuer with the option of continuing to the next instruction by pressing the start button 12′ in the
Returning to decision blocks 106 and 108, if either is positive, the logic will proceed to a block 110 where an emergency notification sequence is initiated by the user interface program 22. As will be described in more detail below, the emergency notification sequence is a subroutine performed by the user interface program 22 to notify the appropriate emergency response system of the patient's collapse.
In one embodiment of the present invention, the rescuer is instructed by the user interface program 22 to notify the appropriate emergency response system. As will be described in more detail below, in other embodiments of the present invention, the AED 10 is programmed to notify the appropriate emergency response system directly. The rescuer initiated emergency notification sequence is depicted in more detail in
In the illustrated embodiment of the present invention, the AED 10 is programmed to notify the emergency response system itself, without human intervention. To do so, those of ordinary skill in the art will recognize that the AED 10 must be equipped with the necessary external interface to communicate with the remote emergency response system. For example, the AED 10 may communicate with the emergency response system via a wireless communication link in which case the external interface of the AED 10 may include an antenna and transceiver for transmitting and receiving radio signals. If communicating via a “wired” communication link, e.g., a “wired” network, a remote telephone/mode connection, a direct port-to-port connection, etc., the AED 10 will be equipped with the appropriate external interface including the necessary circuitry for connecting to the wired communication link and the necessary software for communicating via the appropriate network protocol. Examples of wireless communications capabilities in external defibrillators are discussed in U.S. patent application Publication No. 2004/0124979 and U.S. patent application Publication No. 2003/0212311, both of which are hereby incorporated by reference herein.
The device initiated emergency notification sequence performed by the user interface program 22 is shown in more detail in
Returning to the substance of
Once emergency notification has been completed, the logic proceeds from decision block 146 to a block 150 where a verbal instruction is issued via the speaker 18 confirming that “Emergency Notification Complete.” In addition, a textual instruction of similar nature is generated on the display 14 of the AED 10. The logic then ends in a block 154. If emergency notification has not been completed by the AED 10 and the emergency call interval has expired, then the rescuer initiated emergency notification sequence depicted in
It will be appreciated that the emergency response system notified by either the rescuer or the device may be the public emergency response system for local EMS such as police, fire, etc. or a private emergency response system such as a private security or alarm monitoring system. Consequently, the AED 10 is preprogrammed with the appropriate telephone number for the desired emergency response system. In the United States, the public emergency response system is usually notified by calling 911. However, in some remote areas of the U.S. and in many foreign countries different telephone numbers are assigned to the local, public emergency response system.
Finally, in yet other embodiments of the present invention, the rescuer or device initiated emergency notification sequence may take place separately from the AED 10. For example, if the AED 10 is deployed from a docking station, the docking station could execute the emergency notification sequence if it were equipped with the necessary hardware and software.
Returning to
Returning to block 114, the rescuer is instructed to assess the patient's condition once the patient has been placed in the appropriate position. The patient assessment sequence is shown in more detail in
Returning to decision block 164, if the rescuer does not indicate that the patient is breathing by pressing the “yes” button, and has not input any response, the logic will proceed to a decision block 170 where it determines if the time interval for the rescuer to take action has expired or if the rescuer has pressed the start button 12′ two times (in the
Upon expiration of the rescuer action interval or an indication from the rescuer that the patient is not breathing or the rescuer desires to continue to the next instruction, the logic proceeds to a decision block 172 where it determines if rescue breathing or CPR delivery was just performed. If not, then it is necessary for the AED 10 to instruct the user to deliver rescue breaths before continuing further. To determine whether rescue breathing or CPR delivery was just performed, the user interface program 22 determines whether it has previously instructed the user to deliver rescue breaths as part of the patient assessment sequence or if it has prompted the rescuer to deliver breaths as part of a CPR delivery sequence (described in more detail below) immediately prior to prompting the rescuer to check the patient's breathing. If the result of decision block 172 is positive, the logic proceeds to a block 174 where the AED 10 instructs the rescuer to deliver a predetermined or y number of rescue breaths to the patient where y, for example, is the number of rescue breaths currently recommended under a given standard protocol when a patient is not breathing and a pulse check has not yet been conducted. In accordance with the AHA HeartSaver CPR protocol for adult CPR delivery, this number is presently two. As for generation of the appropriate instruction, the microprocessor 24 of the AED 10 generates a visual instruction as shown in
It will be appreciated by those of ordinary skill in the art that following each verbal instruction to “blow,” there will be a pause of an appropriate length of time before issuing the next verbal “blow” instruction so as to provide the rescuer with sufficient time to perform the instruction. Under the AHA HeartSaver CPR protocol this pause is 1.5 to 2 seconds. Accordingly, the rescuer is guided to perform the instructed task at appropriate time intervals. Alternatively, rather than repeating the verbal instruction to blow, the speaker 18 may repeat an audible tone at predetermined time intervals to assist the rescuer in executing the blow instruction. Further, the corresponding visual instruction generated on the display 14 may be synchronized with the verbal instruction such that the visual instruction flashes at the same time as the verbal instructions are repeated.
Returning to blocks 172 and 174, after rescue breathing has been performed, the logic proceeds to a block 176 where the rescuer is instructed to check the patient's pulse. More specifically, the user interface program 22 causes the microprocessor 24 to generate a visual instruction to check the patient's pulse as shown in
Returning to decision block 178, if the rescuer does not indicate that a pulse has been detected by pressing the “yes” button the logic proceeds to a decision block 182 where if the rescuer has not input any response, it determines if the rescuer action interval has expired, or if the rescuer has pressed the “no” button to indicate that no pulse was detected, or has indicated a desire to continue to the next instruction. If the result of decision block 182 is negative, blocks 178 and 182 are repeated until either a pulse has been detected by the rescuer or until the rescuer action interval has expired or the rescuer has indicated no pulse is detected or a desire to proceed to the next instruction. In the latter case, if the rescuer action interval expires, or if the rescuer proceeds to the next instruction, it is assumed that a pulse has not been detected. Accordingly, the microprocessor 24 is instructed to return in a block 184 to the main user interface program 22 of
As discussed above with reference to
The prompts to the user would be phrased accordingly to instruct the user to push the appropriate response button. For example, the pulse check prompt may be given as “Does the patient have a pulse [or signs of circulation]? Push the ‘yes’ button if patient has a pulse [or signs of circulation]”, or “Does the patient have a pulse [or signs of circulation]? Push the ‘yes’ or ‘no’ button.” The user input mechanism may also be used to provide the rescuer with a mechanism for responding to any other prompts which ask for information on the patient or the patient's condition. The use of hardware buttons with soft keys, or soft buttons on a touch screen, are advantageous in that they allow for a variety of different labels or indications to be associated with a user input button at various times during an event.
Some users of an AED may have difficulty in determining whether or not a patient has a pulse. In another alternative embodiment, a pulse check prompt may be given in a form that accommodates these users and avoids putting them in a situation where they may be confused as to how to respond. For example, the pulse check prompt may be given as: “Press ‘yes’ if you can find a pulse.” The user may also be given the alternative of responding in a manner that indicates that he or she does not know or cannot answer the question. For example, if a prompt says: “Does the patient have a pulse”, “is the Patient breathing, or “did you witness the patient's collapse [or the arrest]?” soft buttons on a touch screen or soft keys with hardware buttons can be programmed to display “yes”, “no” and “I don't know”, or “unknown” or another indication of inability to respond yes or no to a given inquiry. A response that indicates the rescuer does not know if a pulse is present or if the patient is breathing may be treated as a negative response at block 182 in the logic illustrated in
The patient assessment may also include other queries by the device such as an initial query as to whether the rescuer had witnessed the patient's collapse or cardiac arrest, as shown in box 161 of
Referring again to
The logic implemented by the user interface program 22 to perform the electrode attachment sequence is shown in more detail in
Returning to decision block 244, if a proper connection between the patient, electrodes and AED 10 has not been established, the logic proceeds to a decision block 248 where it determines if a time interval allowed for connecting the electrodes 16 to the patient has expired. If not, decision blocks 244 and 248 are repeated until either a proper electrode connection has been established or the electrode connection interval expires. If the electrode connection interval expires without proper connection being established, the logic proceeds to a decision block 250 to determine if the electrode attachment sequence currently being performed was interrupt driven due to detachment of the electrodes from the patient during treatment or if the electrode attachment sequence is being implemented for the first time following deployment of the defibrillator and initial instructions to the rescuer to attach the electrodes. If interrupt driven, it is likely that the electrodes have become detached during CPR delivery or perhaps during the AED sequence. Accordingly, it is prudent for the rescuer to reassess the patient's condition and deliver CPR before attempting to reattach the electrodes. Accordingly, the logic proceeds from decision block 250 to a block 256 where the patient assessment sequence is initiated to instruct the rescuer to again assess the patient for breathing and pulse. Following patient assessment, the logic proceeds to a block 258 where a CPR delivery sequence of instructions described in more detail below is provided to the rescuer. Following patient assessment and CPR delivery, the logic of
Returning to decision block 250, if the current electrode attachment sequence was not interrupt driven, i.e., if the sequence was called from the main user interface program 22 in block 122, the logic proceeds from decision block 250 to a block 252 where the CPR delivery sequence is initiated. It will be appreciated that since the electrode attachment sequence was called in this instance for the first time after power-on, patient assessment has just been instructed. Therefore, CPR may be delivered without reassessing the patient. However, following CPR delivery, the patient assessment sequence is repeated in a block 254. The logic then returns to block 242 and the rescuer is instructed once again to attach the electrodes 16 to the patient. As is readily apparent from the above discussion, the electrode attachment sequence may continue indefinitely until proper connection of the electrodes 16 is established. Accordingly, the rescuer will be instructed repeatedly to assess the patient's condition and deliver CPR until emergency assistance arrives.
As noted above, once proper connection of the electrodes 16 has been established, the logic of the main user interface program 22 proceeds to a block 124 where an AED sequence is initiated which instructs the rescuer in proper operation of the defibrillator so as to provide defibrillation therapy to the patient, if necessary. The logic of the AED sequence is shown in more detail in
Following activation of the automatic rhythm detection algorithm in block 192, the AED 10 notifies the rescuer that analysis has begun and instructs the rescuer to stand clear. More specifically, a visual instruction to stand clear as shown in
Returning to decision block 196, in another embodiment of the present invention, the automatic rhythm detection algorithm is designed to automatically advise delivery of CPR preceding a shock. If so, the AED sequence will skip the determination of whether a sufficient number of cycles of CPR have been delivered and instead proceed directly to block 202 so processing may resume in the main user interface program 22 with delivery of CPR instructions in a block 126.
In another embodiment, if at box 161 the rescuer had input a response to the prompt for whether he had witnessed the patient's collapse, indicating that he did witness the patient going into cardiac arrest, then a shock would be delivered without prior application of CPR. In this case, the question in block 196, “should CPR precede shock” would be answered in the negative and the logic followed by the device would proceed to block 200.
Returning to decision block 198, if the appropriate number of CPR cycles has already been delivered, the logic proceeds to a decision block 200 and continues with the AED sequence so that defibrillation therapy may be delivered if necessary. In decision block 200, the logic decides whether a predetermined or n number of consecutive shocks have already been delivered to the patient. Again, in accordance with the current AHA guidelines the maximum number of consecutive shocks allowed is three. It will be understood that n may equal one. If a maximum number of shocks have been delivered consecutively without successful conversion of the patient's heart to a normal heart rhythm, defibrillation therapy will not continue. Rather, processing will return in a block 202 to the main user interface routine so that CPR delivery can be instructed to the user in a block 126. However, if the maximum number of consecutive shocks has not yet been reached, the logic will proceed in
On the other hand, if a shockable rhythm is detected in decision block 204, the logic proceeds to a block 205 in which the AED instructs the user verbally that “Shock Advised, Stand Clear.” In addition, the microprocessor 24 generates a corresponding visual instruction such as that shown in
Once the device is ready to shock, the logic proceeds to a block 212 on
If the shock delivery interval has expired before a defibrillation pulse is delivered to the patient, the logic proceeds to a decision block 220 where it determines if the rescuer or AED 10 has had a predetermined or k number of chances to shock the patient. In the embodiment of the present invention described herein, the rescuer is given three opportunities to shock the patient. If those three opportunities have not yet been provided, the logic returns to block 192 of
Returning now to
In this or other embodiments of the invention, some of the steps shown in
Once the rescuer has delivered the predetermined number of compressions in block 232, the logic proceeds to a block 234 where the rescuer is instructed to deliver q breaths to the patient, where y is a predetermined number of breaths preprogrammed into the user interface program 22. In the present example, q is the number of breaths required under the AHA CPR protocol for an adult, typically two. The visual instruction for delivery breaths generated by the microprocessor 24 on the display 14 of the AED 10 is shown in
Next, in a decision block 236, the logic determines if a predetermined or r number of CPR cycles has been delivered. In other words, the logic determines if blocks 232 and 234 been executed a predetermined number of times. In the embodiment of the present invention described herein, r is the number of CPR cycles recommended under the AHA CPR protocol for an adult. However, it will be appreciated that this number as well as any of the others mentioned above may vary depending on the protocol preprogrammed into the user interface program 22. If the recommended number of CPR cycles has not been delivered, blocks 232, 234 and 236 are repeated until the appropriate number of cycles has been delivered. At that point, processing returns in a block 238 to the routine from which the CPR delivery sequence was called, e.g., user interface program 22, electrode attachment sequence, etc. Those of ordinary skill in the art will appreciate that in other embodiments of the present invention, an alternative test for determining when CPR has been sufficiently performed can be implemented in decision block 236. For example, block 236 may determine whether CPR has been delivered for a predetermined time interval t. For example, under the AHA protocol for CPR for an adult, time t is one minute.
Returning to
While a number of embodiments of the present invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, although the user interface program 22 depicted in
In yet other embodiments of the present invention, the verbal instructions provided to the rescuer simultaneously and in synchronization with the visual instructions could be repeated periodically until the rescuer proceeds to the next instruction. Consequently, the rescuer would continually receive each verbal instruction until the next action is taken. In yet other embodiments, the rescuer could proceed to the next instruction by issuing a voice command to the AED 10 rather than by pressing a button. In such embodiments, the AED 10 would be required to have installed a voice recognition module and microphone as noted above. In yet other embodiments of the present invention, the user interface program 22 can prompt the user to input information regarding the patient that would assist the user interface program in providing more patient specific instructions to the rescuer. For example, the user interface program 22 could generate visual and/or verbal instructions to enter information via the start button 12′ Of
It will also be appreciated that the processes and protocols shown in the Figures and discussed above are illustrative and the processes and protocols followed by various embodiments of the invention may vary from what has been illustrated. Examples of other procedures and protocols that may be followed by a device according to an embodiment of the invention are discussed in U.S. pending patent application Ser. No. 11/044,871 filed on Mar. 31, 2005 and Ser. No. 11/095,305 filed on Mar. 31, 2005, Ser. No. 11/013,894 filed on Dec. 15, 2004 (all of which are owned by the same entity which owns the present application), all of which are incorporated herein by reference.
It will further be appreciated that the visual and aural instructions provided by the intuitive user interface of the present invention may vary from those noted above and illustrated. For example, more information and instruction may be provided to a layperson for clarity and to reduce anxiety. In addition, instructions may be provided with less medical jargon. Accordingly, an even more user friendly user interface is provided. Those of ordinary skill in the art will also recognize that as accepted CPR and defibrillation protocols change, e.g., by adding, deleting or reordering instructions, the AED 10 may be reprogrammed with a simple software upgrade to the user interface program 22 to achieve compliance. For example, the AED 10 may be reprogrammed to add visual and/or aural instructions to unobstruct the patient's airway. Finally, it will be appreciated that any defibrillation device, e.g., a manual defibrillator, a semi-automatic defibrillator or a fully automatic defibrillator, may be equipped with the user interface of the present invention.
This application is a continuation-in-part of U.S. patent application Ser. No. 10/754,338, filed on Jan. 9, 2004, which is a continuation of U.S. Pat. No. 6,697,671, which is a continuation of U.S. Pat. No. 6,334,070, which claims the benefit of U.S. provisional Application 60/109,168, filed on Nov. 20, 1998, all of which are hereby incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 60109168 | Nov 1998 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09972028 | Oct 2001 | US |
| Child | 10754338 | Jan 2004 | US |
| Parent | 09444037 | Nov 1999 | US |
| Child | 09972028 | Oct 2001 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10754338 | Jan 2004 | US |
| Child | 11262369 | Oct 2005 | US |
