Automatic external defibrillator with automatic selection between adult and pediatric defibrillation doses

Abstract

An AED and method of use are described that include two pads for placement on a patient, two electrodes respectively on the two pads, two angular motion sensors respectively associated with the two pads, a shock generation circuit that generates a dosage of a defibrillation shock, and a processor having a memory and a power source, the processor being configured to analyze angular motion signals from the two angular motion sensors to determine an orientation of the two pads relative to one another, analyze electrocardiogram (ECG) signals from the two electrodes to determine a shockable cardiac rhythm, and automatically select between an adult dosage and a pediatric dosage of a defibrillation shock delivered by the two electrodes based at least in part on the orientation of the two pads.

Description

[Technical field]

[0001] The present invention relates generally to an automated external defibrillator (AED) with automatic selection between adult and pediatric defibrillation dosages. [Background technology]

[0002] Existing AEDs are configured to deliver adult-dose and pediatric-dose defibrillation shocks having different energies using two electrodes on two defibrillation pads, respectively. Most AEDs have a visual guide for pad placement that relies on placing the electrodes in specific locations that differ for adult and pediatric patients.

[0003] Adult-dose defibrillation shocks are typically delivered using two pads placed on an adult patient in an anterior-anterior orientation, with one electrode being a sternal electrode and the other an apical electrode. Low-energy pediatric-dose defibrillation shocks are typically delivered using two pads placed on a child patient in an anterior-posterior orientation, with one electrode being a precordial electrode and the other a dorsal electrode.

[0004] Conventional AEDs have several shortcomings: Selection between adult and pediatric doses for child patients is not fully automated, instead requiring a caregiver to manually select the child dose and prevent malfunction with the adult dose, such as the use of a push button or key insert that manually sets the AED's operation in "child mode," or child-specific pads and / or leads that manually wire the AED to operate in "child mode."

[0005] One of the key requirements for an AED is a compact device form factor with a reduced pad footprint, which creates internal packaging space constraints that limit battery size, which in turn limits the cycle life and shelf life of conventional AEDs.

[0006] The configuration used in conventional AEDs to manually select between adult and pediatric defibrillation doses reduces the internal space available for packaging the battery, which in turn further limits the cycle life and shelf life of the compact AED.

[0007] One such configuration of a defibrillator that uses a motion sensor for electrode placement determination and dosage management is disclosed in EP 3679353.

[0008] However, some of the disadvantages of the method and apparatus of EP 3679353 include the following: Use of separate pads for infant and adult doses. · EP 3679353 does not use the TTI to distinguish between adults and infants / children (as separate pads are used). Determination of the relative orientation of the pads and spacing limitations for pad placement is highly prone to error due to variations in patient size, chest topography, and other factors such as the presence of implantable cardioverter defibrillators and pacemakers that require the electrodes to be moved from the standard positions. · Anthropometric models used to determine patient size vary significantly by population type and gender and therefore may not provide an accurate assessment of the patient. The device of EP 3679353 extends the time it takes to deliver a shock to the patient as a result of the requirement for interaction from the user (i.e. confirmation of a step to be taken to confirm pad position or additional steps to be taken).

[0009] With this background in mind, there is an unmet need for AEDs with improved configurations for selecting between adult and pediatric dose defibrillation shocks. In addition, there is an unmet need for AEDs capable of therapeutic use in non-hospital or medical settings where the user does not have the training or expertise in the use of AEDs.

[0010] It is an object of the present disclosure to provide an improved automatic dose adjustment system and an automatic external defibrillator having the same that addresses or ameliorates one or more shortcomings or limitations associated with the prior art, or at least provides the public with a useful choice. Summary of the Invention

[0011] In one aspect, the disclosure can provide an AED having a small form factor having a housing and all components located within or on the housing, the AED comprising two or more angular motion sensors that enable the AED to determine the relative orientation of the AED electrodes and automatically select between an adult dose and a pediatric dose defibrillation shock based on the orientation of the AED electrodes.

[0012] In one aspect, the present disclosure provides an AED, comprising: Two pads to be placed on the patient; Two electrodes on two pads each, two angular motion sensors associated with two pads respectively; a shock generation circuit for generating a dose of a defibrillation shock; a processor having a memory and a power supply, the processor comprising: analyzing the angular motion signals from the two angular motion sensors to determine an orientation of the two pads relative to one another; analyzing electrocardiogram (ECG) signals from the two electrodes to determine a shockable cardiac rhythm; An AED may be provided that is configured to automatically select between an adult-dose defibrillation shock and a pediatric-dose defibrillation shock delivered by the two electrodes based at least in part on the orientation of the two pads.

[0013] According to a further aspect, the present disclosure provides an AED comprising two pads for placement on a patient, each pad comprising: At least one electrode; an angular motion sensor; At least one pad is a shock generation circuit configured to generate a dose of a defibrillation shock; a processor having a memory and a power source; The processor analyzing the angular motion signals from each of the two angular motion sensors to determine an orientation of the two pads relative to one another; analyzing electrocardiogram (ECG) signals from the two electrodes to determine a shockable cardiac rhythm; An AED may be provided that is configured to automatically select between an adult-dose defibrillation shock and an infant-dose defibrillation shock delivered by the two electrodes based at least in part on the relative orientation of the two pads.

[0014] In another aspect, the present disclosure provides a method of using an AED, comprising: receiving angular motion signals from two angular motion sensors associated with two pads placed on the patient for delivering defibrillation shocks by two electrodes on the two pads, respectively; analyzing the angular motion signal to determine an orientation of the two pads relative to one another; and automatically selecting between an adult dose and a pediatric dose of a defibrillation shock delivered by the two electrodes based at least in part on an orientation of the two pads.

[0015] In another aspect, the present disclosure provides a method of using an AED, comprising: receiving an angular motion signal from each of at least two angular motion sensors, each sensor located on a pad placed on the patient, each pad including an electrode; analyzing the angular motion signal to determine an orientation of the two pads relative to one another; and automatically selecting between an adult-dose and an infant-dose defibrillation shock delivered by the two electrodes based at least in part on the relative orientation of the two pads.

[0016] The following configurations may be relevant to any of the above aspects.

[0017] In one configuration, each angular motion sensor may include one or more of an inertial measurement unit (IMU), a gyroscope sensor, and an accelerometer.

[0018] In one configuration, an infant dose defibrillation shock may have a lower energy than an adult dose defibrillation shock.

[0019] In one configuration, the processor may be configured to automatically select an adult dose defibrillation shock if the two pads are determined to have an anterior-anterior orientation, such that one of the two electrodes is a sternal electrode and the other is an apex electrode.

[0020] In one configuration, the processor may be configured to automatically select an infant-dose defibrillation shock if the two pads are determined to have an anterior-posterior orientation, such that one of the two electrodes is a precordial electrode and the other is a dorsal electrode.

[0021] In one configuration, the process may be further configured to provide a fail-safe indication of whether the patient is an adult or an infant.

[0022] In one configuration, transthoracic impedance (TTI) measurements may be obtained from the two electrodes, and the processor may be further configured to analyze the TTI measurements to provide a fail-safe indication of whether the patient is an adult or an infant.

[0023] In one configuration, the processor may be further configured to automatically select between an adult-dose and a pediatric-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and an analysis of the TTI measurements from the two electrodes.

[0024] In one configuration, each pad may include at least three angular motion sensors, and the processor may be further configured to analyze the angular motion signals from a majority of the angular motion sensors on each pad to provide a fail-safe indication of whether the patient is an adult or an infant.

[0025] In one configuration, the processor may be further configured to automatically select between an adult-dose and a pediatric-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and an analysis of the angular motion signals from a majority of the angular motion sensors on each pad.

[0026] In one configuration, the method may further include providing a fail-safe indication of whether the patient is an adult or an infant.

[0027] In one configuration, the method comprises: receiving transthoracic impedance (TTI) measurements from two electrodes; and Analyzing the TTI measurements from the two electrodes to provide a fail-safe indication of whether the patient is an adult or an infant.

[0028] In one configuration, the method may further include automatically selecting between an adult-dose defibrillation shock and an infant-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and an analysis of the TTI measurements from the two electrodes.

[0029] In one configuration, the method comprises: receiving angular motion signals from at least three angular motion sensors located on each pad; analyzing the angular motion signals received from a majority of the angular motion sensors on each pad to provide a fail-safe indication of whether the patient is an adult or an infant.

[0030] In one configuration, the method may further include automatically selecting between an adult-dose and a pediatric-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and an analysis of the angular motion signals from a majority of the angular motion sensors on each pad.

[0031] As used herein, the term "axis" refers to an axis of rotation about which a line or plane can be rotated to form a symmetrical shape. For example, a line rotated about an axis of rotation forms a surface, and a plane rotated about an axis of rotation forms a solid.

[0032] The term "comprising" as used in this specification and the claims means "consisting at least in part of." When interpreting each statement in this specification that contains the term "comprising," there may be other features present than the feature preceded by that term. The related terms "comprise" and "comprises" should be interpreted in the same manner.

[0033] As used herein, the term "and / or" means "and" or "or," or both.

[0034] As used herein, "(plural)" following a noun refers to the plural and / or the singular form of the noun.

[0035] For purposes of this specification, when method steps are listed in a sequence, the sequence does not necessarily imply that the steps are chronologically ordered in that sequence, unless there is another logical way to interpret the sequence.

[0036] The term "comprising" as used in this specification and the claims means "consisting at least in part of." When interpreting each statement in this specification that contains the term "comprising," there may be other features present than the feature preceded by that term. The related terms "comprise" and "comprises" should be interpreted in the same manner.

[0037] The invention may also be broadly described as consisting in any or all combinations of any two or more of the parts, elements or features, either individually or collectively, referred to or indicated in the specification of this application, and where a specific integer having known equivalents in the art to which the invention pertains is referred to herein, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0038] Numerous modifications of the structure and widely different embodiments and applications of the present invention will be suggested to those skilled in the art to which the present invention pertains without departing from the scope of the invention, which is defined in the appended claims. The disclosures and descriptions herein are purely illustrative and are not intended to be in any sense limiting.

[0039] Other aspects of the invention will become apparent from the following description, given by way of example only and referring to the accompanying drawings, in which: [Brief description of the drawings]

[0040] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a block diagram of an AED according to one embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of an AED for use in adults. [Figure 3A] FIG. 1 is a schematic diagram of an AED for use on children. [Figure 3B] FIG. 1 is a schematic diagram of an AED for use on children. [Figure 4A] 1A and 1B are schematic diagrams showing the relative orientation of the pads before and after snapping, respectively. [Figure 4B] 1A and 1B are schematic diagrams showing the relative orientation of the pads before and after snapping, respectively. [Diagram 5] FIG. 1 is a schematic diagram showing the orientation of the pads when the AED is used on a child. [Figure 6] FIG. 1 is a block diagram showing information flow when using an additional processor in an AED. [Figure 7] FIG. 7 is a block diagram showing the information flow when adding a hardware filter to use an additional processor as shown in FIG. 6. [Figure 8] FIG. 1 is a flow diagram showing the process flow from snap-through to shock when using an AED. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] 1, an AED 100 according to an embodiment of the present invention may generally include two defibrillation pads 110 that are placed on a patient. The two pads 110 may be connected by a lead 120. Two electrodes 130 may be provided on each of the two pads. That is, each pad 110 may include at least one electrode 130. Two or more angular motion sensors 140 may be associated with each of the two pads 110. That is, each pad 110 may include at least one angular motion sensor 140. The two angular motion sensors 140 may include an IMU, a gyroscope sensor, an accelerometer, or a combination thereof.

[0042] An electronics module 150 may be packaged inside one or both of the two pads 110. The electronics module 150 may include a shock generation circuit for generating a dose of defibrillation shock, a processor with memory, and a power source, such as a battery. Each of the shock generation circuit, processor, and power source may be located within one pad 110 or distributed across the two pads 110. A suitable compact AED 100 is described in further detail in applicant's International Publication No. WO 2018 / 232450, which is incorporated herein by reference in its entirety.

[0043] The processor may be configured to analyze the angular motion signals from the two angular motion sensors 140 to determine an orientation of the two pads 110 relative to one another. The processor may be further configured to automatically select between an adult-dose defibrillation shock and a pediatric-dose (also referred to as an infant-dose, where the patient weight is in the range of about 1.5 kg to about 9.5 kg) defibrillation shock delivered by the two electrodes 130 based at least in part on the orientation of the two pads 110. The pediatric-dose defibrillation shock may have a lower energy than the adult-dose defibrillation shock.

[0044] For example, as shown in FIG. 2, the processor may be configured to automatically select an adult dose defibrillation shock if it is determined that the two pads 110 have an anterior-anterior orientation, such that one of the two electrodes 130 is a sternal electrode 130a and the other is an apex electrode 130b.

[0045] Alternatively, as shown in Figures 3A and 3B, the processor can be configured to automatically select a pediatric dose of defibrillation shock if it is determined that the two pads 110 have an anterior-posterior orientation, such that one of the two electrodes 130 is a precordial electrode 130a (Figure 3A) and the other is a dorsal electrode 130b (Figure 3B).

[0046] The processor may also be configured to analyze the ECG signals from the two electrodes 130 to determine a shockable cardiac rhythm.

[0047] The AED 100 may be configured to provide or include a fail-safe indication of whether the patient is an adult or an infant.

[0048] If the processor establishes that the angular motion signals obtained from the at least two angular motion sensors 140 may not accurately determine the orientation of the two pads, or if there is no positive indication of the orientation of the pads, or if the patient is an adult or an infant, the AED may be configured to provide or include a fail-safe indication of whether the patient is an adult or an infant.

[0049] A TTI measurement may also be obtained from the two electrodes, and the processor may be further configured to analyze the TTI measurement. One of the fail-safe instructions provided in the AED may include determining the patient's age group (i.e., whether the patient is an infant or an adult) based on the TTI measurement.

[0050] The processor may further be configured to automatically select between an adult dose and a pediatric dose of a defibrillation shock delivered by the two electrodes 130 based on a combination of the orientation of the two pads 110 and an analysis of the TTI measurements from the two electrodes 130.

[0051] Note that the main factors of interest in determining whether a patient is an adult or an infant are related to pad size, body dimensions, age, and to a lesser extent hairiness, as other factors are consistent between the two groups. Body dimensions and age are often related in that people increase in size as they get older, but overall larger people will have a higher TTI than their smaller counterparts. Hairiness is the amount of hair on the chest that affects the ability of the electrode pads to fully contact the chest, increasing the possible range of adult TTI.

[0052] To determine the correct dosage of the defibrillation shock (i.e., pediatric or adult dosage), the processor may be configured to analyze both the orientation data received from the angular motion signals from the at least two angular motion sensors and the TTI measurement to determine whether the patient is an adult or an infant.

[0053] The processor may establish that the data received from both of the at least two angular motion sensors 140 and the TTI measurements are inconsistent as to whether the patient is an adult or an infant. The processor may be configured to switch the dosage to that of an adult patient, since although there are potential risks associated with delivering an adult dosage to an infant, defibrillation would still be effective and would achieve the desired result of arresting the arrhythmia. Conversely, if an adult received an infant dosage, they may not receive sufficient defibrillation energy and the shock would be ineffective.

[0054] TTI requires that a test pulse (current) be sent between the pads or a shock be delivered. Of particular importance to the usefulness of TTI as a determinant of patient age (adult vs. infant) is the effect of pad size on TTI measurement. In conventional defibrillators, there are typically separate pads for pediatric (i.e., infant) and adult patients, with the pediatric pads typically being smaller to account for the smaller body size. A reduction in pad size has been shown to increase TTI, with results showing similar or even higher TTI for infants / children compared to adults with conventional pads. This makes it nearly impossible for conventional defibrillators, especially those with different sized pads for adult and infant patients, to differentiate dosage based on TTI, as the two ranges overlap significantly.

[0055] The present disclosure may provide an AED that uses integrated pads, so pad size remains constant for all patients. Since TTI is known to increase with increasing body size, the TTI for adults vs. children vs. infants is expected to reflect this relationship. The claimed AED is configured to employ an additional safety feature in the form of a fail-safe means for its automatic dose selection that is not available in other defibrillators.

[0056] Furthermore, because the measure of TTI is highly variable and related to multiple factors, it would be difficult to accurately detect a patient's age or size with any meaningful granularity based on this measure alone. As a result, in this disclosure, the TTI measurement is treated as a threshold above which a person is considered an adult and below which a person is considered an infant.

[0057] With reference to Figures 4A and 4B, the determination of the orientation of the pads is disclosed. To some extent, the mathematics for determining the orientation can be simplified to a discrete range of values. Figures 4A and 4B disclose an AED 100 having at least two motion sensors embedded in each of the two pads. The coordinate system of each pad is labeled x, y, and z, respectively.

[0058] As will be appreciated by those skilled in the art, these coordinate systems are merely examples; i.e., the sensor can be placed in any orientation within the pad, provided the orientation is known. For example, if a situation requires the sensor to be placed in an orientation that is not directly aligned with the AED 100, a mathematical transformation is applied to address the ambiguity.

[0059] As a result, the AED 100 can provide an indication of the relative position of the pads in space based on the orientation of the coordinate system. The initial orientation of the pads is shown in FIG. 4A, and the orientation of the pads after snapping is shown in FIG. 4. The gray line in this figure indicates the gel at the bottom of the device. Both pads are connected by an electrical contact (e.g., a wire), as shown in black.

[0060] For an adult patient, the pads can be expected to be broadly aligned in the z direction. In both Figures 4A and 4B, the y direction is indicated by the labels x, y, and z, respectively. This is based on conventional axis orientation, but in some implementations this may be referred to as the z direction. Note that there may be some variation in the exact orientation of the axes as a result of body shape and pad position, but in practice the orientation will result in both z axes being positively aligned.

[0061] 5, for an infant patient, the pads may be positioned in an anterior-posterior direction, meaning that the two pads may have opposite orientations. Thus, the relative orientation of the two pads is positive / negative, whereas the adult positioning is positive / positive. It should be appreciated that there may still be some variation in the placement of infant pads, but this is much less susceptible to pad placement errors than adults, as there are less options for where to place the pads in an infant.

[0062] The methods for determining the orientation of a sensor may vary slightly between sensors. However, in most cases, the requirement may be to collect data and then process the collected data to obtain a resulting output. As a result, the range of data required may vary between each use case scenario.

[0063] The accelerometer may be configured to measure, for example, the acceleration due to gravity orienting itself. Since gravity always acts in the same direction, an AED 100 at rest (placed gel-side down on a surface and not moving) will have an acceleration of −9.8 ms in the z-direction. -2or -1g acceleration. If the device remains in place as its orientation changes (e.g., placed on its side), its acceleration will be recorded across multiple axes to produce a resulting acceleration vector of the same value. Based on the above values, and by knowing the initial orientation of the sensors in the device, the vertical orientation of the accelerometer can be determined from the gravity vector alone, and thus may not strictly require recording of data from the AED 100 snap event.

[0064] For gyroscope-based sensors, the orientation detection method may differ from the above. For example, for gyroscope-based sensors, the orientation determination is based on knowing where the sensor is initially placed and recording snap events to track the orientation change up to the pad placement. Since relative orientation is the main concern in this application, the error introduced by the snap can be accounted for by comparing the two pads.

[0065] 6, the determination of pad orientation and required shock in the AED 100 is shown. The AED may further include a dedicated motion analysis processor configured to receive data from the angular motion sensors in each pad and process the received data. The dedicated angular motion analysis processor may be configured to determine the orientation or motion of the pads relative to each other.

[0066] Some of the difficulties in accurately measuring sensor orientation include additional processing power, especially for sensor types that require recording from the snap event to placement. For example, data from such types of sensors must be stored for processing or processed live, which reduces storage requirements but can increase computing power.

[0067] Furthermore, in the case of infant placement, there may be additional steps involved in placing the pad on the rear side (turning the body over, removing clothing from back vs. front), which may increase the time the sensor needs to record in order to be able to track the orientation / position of the pad. This in turn may increase the computing power required. Furthermore, if the motion sensor provides a new verdict after each classification cycle (in the case of multiple shocks), this data may need to be collected continuously.

[0068] The flow of information through the AED to determine orientation and required shock can take two paths: In the first path, the data can be processed using a processor (also called the main processor).

[0069] In an alternative route, the data can be processed using a dedicated motion analysis processor to avoid any delay in sorting the data received from the angular motion sensors, as this is the most critical process for treatment and is time sensitive.

[0070] As shown in Figure 6, a dedicated angular motion processor receives and provides the relevant data to a main processor (referred to as processor) after determining the appropriate dosage. The processor may also send a signal back to the motion analysis processor to prompt a recalculation of the orientation after the pads have been adjusted. Once the processor has determined the dosage based on the orientation of the pads, the dosage information may be provided to a shock generation circuit to generate the appropriate shock required at each of the electrodes.

[0071] Further, it will be appreciated that data collected from a motion sensor is often noisy. The present disclosure may provide an AED configured to measure the noise from the sensor and remove the noise by applying signal processing techniques, such as digital or analog filters. In some cases, the filter may be a hardware filter. In other cases, the filter may be software-based.

[0072] FIG. 7 is a diagram in the form of a block diagram illustrating the information flow of FIG. 6 with the addition of a hardware filter configured to receive data from the motion sensor and process / remove noise before passing it to the motion processor.

[0073] Referring to FIG. 8, the process flow from snap-through to shock when using an AED is shown in the form of a flow chart. First, in step 801, a determination may be made as to whether the pads have been snapped apart from each other in their original position. If it is determined in step 802 that the pads can be snapped, the sensors are activated and actively recording data. In step 803, the pads may be placed on the patient. Step 804 is the classification stage, where the AED may determine the type of patient being treated and the defibrillation dose required by the patient. The classification step 804 may be divided into three simultaneous blocks: (i) TTI, (ii) motion sensor, and (iii) ECG analysis.

[0074] The TTI block (step 805) may measure and compare the TTI values ​​to determine if the pads are positioned on an adult or an infant, and may perform additional existing checks if the TTI indicates incorrect placement and prompt adjustments. The Motion Sensor block (step 806) may process the data received from the angular motion sensor to determine the relative orientation of the two pads. In a next step, the patient decision based on the pad orientation is compared to the patient decision based on the TTI values.

[0075] In step 807, the ECG block may be configured to determine whether a shockable rhythm is present. If a shockable rhythm is not detected, the device may prompt according to its normal protocol, including but not limited to initiating CPR. Conversely, if a shockable rhythm is detected, the shock generation circuitry may begin charging the pads for a shock.

[0076] While charging the pad, in step 810, the processor may select an appropriate dosage based on Table 1. As shown in Table 1, the device may be configured to prioritize an adult dosage over an infant dosage when measurements from the motion sensor and the TTI do not match each other.

[0077] [Table 1]

[0078] Additionally, the classification phase also includes a check in step 808 where if a shockable rhythm is not detected and the TTI or motion sensors indicate insufficient placement, the user may be instructed to adjust pad placement. A further check is also performed in step 809 where if it is determined during the classification phase that a shockable rhythm is not detected, this information may be relayed so that the user may administer an alternative therapeutic measure, such as CPR.

[0079] In use case scenarios where the determined orientation of the sensor may indicate an out-of-range value, the device may be configured to default to an adult shock.

[0080] The AED100 provides a fail-safe indication of whether the patient is an adult or a child. i) a potentiometer, or ii) an inductor, or iii) a plurality of gaze sensors; or iv) By placing a physical cable between the two pads, or v) any combination of two or more of (i) to (iv); and estimating a distance between the two pads based on data received from

[0081] The AED 100 may further include at least three angular motion sensors disposed on each of the pads. In these implementations, the AED may be configured to provide a fail-safe indication of whether the patient is an adult or an infant based on the data received from each sensor to allow for redundancy in the event of a sensor failure or calibration problem.

[0082] In the above implementation where at least three angular motion sensors are placed on each of the pads, the results from all three sensors may be calculated separately and a majority vote (i.e., two of the three sensors show orientation agreement) may be used to select the dose. In this scenario, it may be preferable for at least one sensor to be an IMU, since the outputs from the accelerometer and gyroscope can be combined for greater accuracy. Furthermore, in this implementation, due to the increased number of sensors, it may be possible to increase the threshold for the infant TTI value to allow for greater accuracy in selecting the dose.

[0083] Additionally, in implementations where multiple sensors are used, multiple sensors may malfunction or return incorrect results. This could be for a number of reasons, but under a majority voting system, two failed sensors on one pad could result in a number of different scenarios. In most cases, pad positioning will be indeterminate, resulting in the adult dose being the best treatment choice.

[0084] In an alternative scenario where two failed sensors could override the functioning sensors and return the opposite orientation of the pads, For infants, this may return a low-risk adult dose determination; For an adult, this may result in the motion sensor returning an infant determination (in this situation, if the TTI also returns an infant value, this may result in an infant dosage being given to the adult, which may not be valid).

[0085] The TTI tends to be increased under most factors that distinguish adults from young children, and therefore it is unlikely that the TTI will also fail to return an accurate reading.

[0086] An additional scenario could be defibrillation of a small child who may have a low enough TTI to register as an infant. In this case, an infant dose could be given to the child, but this is a low risk since many defibrillators deliver low dose shocks to children as well as infants. However, because of this, the TTI would not be able to be removed as a fail-safe measure.

[0087] Thus, in this device, the use of multiple sensors may produce more accurate readings and allow the TTI threshold to be increased due to greater confidence in the motion sensor results.

[0088] In the present disclosure, the sensor may be configured to measure the relative orientation of the pad and therefore may be placed in any known fixed position and orientation within the pad, however, it may be preferred to mount the sensor to the PCB itself as this may provide the most stable mounting point for the sensor.

[0089] The AED may have one sensor located on the controller side of the board (which has the battery and processor) and the other sensor located on the capacitor bank side. The device may also have an extra wire added to the cable connecting the two pads to transmit data to the controller side.

[0090] Each pad of the defibrillator is approximately 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or 200 cm 3and a useful range can be selected from any of these values ​​(e.g., about 100 to about 200, about 100 to about 180, about 100 to about 160, about 100 to about 150, about 110 to about 200, about 110 to about 190, about 110 to about 170, about 110 to about 150, about 120 to about 200, about 120 to about 180, about 120 to about 150, about 130 to about 200, about 130 to about 180, about 130 to about 150, about 140 to about 200, about 140 to about 180, about 140 to about 160, or about 140 to about 150 cm). 3 ).

[0091] Each pad of this defibrillator is approximately 50, 60, 70, 80, 90 or 100 cm 2 and a useful range can be selected from any of these values ​​(e.g., about 50 to about 100, about 50 to about 80, about 50 to about 70, about 50 to about 60, about 60 to about 100, about 60 to about 80, about 60 to about 70, or about 50 to about 60 cm). 2 ).

[0092] A compact AED configured for single-use defibrillation therapy and resuscitation of a patient is described. The device is configured to automatically select between an adult-dose defibrillation shock and an infant-dose defibrillation shock delivered by two electrodes based at least in part on the relative orientation of the two pads. The resulting device is user-friendly and requires minimal training or knowledge regarding its operational use. Thus, points of confusion for users unfamiliar with the device are eliminated.

[0093] For example, the volume of each pad is 153 cm 3 9.7 cm x 9.3 cm x 1.7 cm, with a surface area of ​​70.5 cm 2 , the total surface area may be approximately 8.2 cm by 8.6 cm.

[0094] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention provide an AED that is generally and specifically useful for automatically selecting between adult-dose and pediatric-dose defibrillation shocks.

[0095] Embodiments of the present invention advantageously omit the space-consuming manual fail-safe mechanism used in conventional AEDs to manually select between adult-dose and pediatric-dose defibrillation shocks. The elimination of the manual fail-safe mechanism may advantageously increase (or "buy back") the internal packaging space available for the battery, which in turn may increase the cycle and shelf life of the compact AED.

[0096] In other words, automatic selection between adult and pediatric dosages may facilitate optimal use of the internal packaging space in a compact AED for power delivery. For example, embodiments of the present invention may facilitate a compact AED with a target shelf life of at least one year or up to two years.

[0097] Although the embodiments have been described with reference to certain exemplary embodiments, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[0098] Many modifications will be apparent to those skilled in the art without departing from the scope of the invention as described herein with reference to the accompanying drawings.

Claims

1. 1. An automated external defibrillator (AED) comprising two pads for placement on a patient, each pad comprising: At least one electrode; an angular motion sensor; At least one pad comprises: a shock generation circuit configured to generate a dose of a defibrillation shock; a processor having a memory and a power source; The processor, analyzing the angular motion signals from each of the two angular motion sensors to determine an orientation of the two pads relative to one another; analyzing electrocardiogram (ECG) signals from the two electrodes to determine a shockable cardiac rhythm; the AED is configured to automatically select between an adult-dose and an infant-dose defibrillation shock delivered by the two electrodes based at least in part on the orientation of the two pads relative to one another.

2. 10. The AED of claim 1, wherein each angular motion sensor includes one or more of an inertial measurement unit (IMU), a gyroscope sensor, and an accelerometer.

3. 3. The AED of claim 1 or 2, wherein the infant dose defibrillation shock has a lower energy than the adult dose defibrillation shock.

4. 4. The AED of claim 1, wherein the processor is configured to automatically select the adult-dose defibrillation shock if the two pads are determined to have an anterior-anterior orientation such that one of the two electrodes is a sternal electrode and the other is an apex electrode.

5. 5. The AED of claim 1, wherein the processor is configured to automatically select the infant-dose defibrillation shock if the two pads are determined to have an anterior-posterior orientation such that one of the two electrodes is a precordial electrode and the other is a dorsal electrode.

6. The AED of any one of claims 1 to 5, wherein the processor is further configured to provide a fail-safe indication of whether the patient is an adult or an infant.

7. 7. The AED of any one of claims 1 to 6, wherein transthoracic impedance (TTI) measurements are obtained from the two electrodes, and the processor is further configured to analyze the TTI measurements to provide a fail-safe indication of whether the patient is an adult or an infant.

8. 8. The AED of claim 7, wherein the processor is further configured to automatically select between the adult-dose and the infant-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and the analysis of the TTI measurements from the two electrodes.

9. 9. The AED of any one of claims 1 to 8, wherein each pad comprises at least three angular motion sensors, and the processor is further configured to analyze angular motion signals from a majority of the angular motion sensors on each pad to provide a fail-safe indication of whether the patient is an adult or an infant.

10. 10. The AED of claim 9, wherein the processor is further configured to automatically select between the adult-dose and the infant-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and the analysis of the angular motion signals from the majority of the angular motion sensors on each pad.

11. 1. A method of using an automated external defibrillator, comprising: receiving an angular motion signal from each of at least two angular motion sensors, each sensor located on a pad placed on the patient, each pad including an electrode; analyzing the angular motion signals to determine an orientation of the two pads relative to one another; and automatically selecting between an adult dose and an infant dose defibrillation shock delivered by the two electrodes based at least in part on the relative orientations of the two pads.

12. The method of claim 11 , wherein each angular motion sensor includes one or more of an inertial measurement unit (IMU), a gyroscope sensor, and an accelerometer.

13. 13. The method of claim 11 or 12, wherein the infant dose defibrillation shock has a lower energy than the adult dose defibrillation shock.

14. 14. The method of claim 11, further comprising automatically selecting the adult dose of defibrillation shock if the two pads are determined to have an anterior-anterior orientation such that one of the two electrodes is a sternal electrode and the other is an apex electrode.

15. 15. The method of any one of claims 11-14, further comprising automatically selecting an infant-dose defibrillation shock if the two pads are determined to have an anterior-posterior orientation such that one of the two electrodes is a precordial electrode and the other is a dorsal electrode.

16. The method of any one of claims 11 to 15, further comprising providing a fail-safe indication of whether the patient is an adult or a child.

17. receiving transthoracic impedance (TTI) measurements from the two electrodes; 17. The method of any one of claims 11 to 16, further comprising analysing the TTI measurements from the two electrodes to provide a fail-safe indication of whether the patient is an adult or an infant.

18. 18. The method of claim 17, further comprising automatically selecting between the adult-dose and the infant-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and the analysis of the TTI measurements from the two electrodes.

19. receiving angular motion signals from at least three angular motion sensors located on each pad; 19. The method of any one of claims 11 to 18, further comprising analysing the angular motion signals received from a majority of the angular motion sensors on each pad to provide a fail-safe indication of whether the patient is an adult or an infant.

20. 20. The method of claim 19, further comprising automatically selecting between the adult-dose and the infant-dose defibrillation shock delivered by the two electrodes based on a combination of the relative orientation of the two pads and the analysis of the angular motion signals from the majority of the angular motion sensors on each pad.

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