Patent Description:
Cardiac arrest and other cardiac health ailments are a major cause of death worldwide. Various resuscitation efforts aim to maintain the body's circulatory and respiratory systems during cardiac arrest in an attempt to save the life of the victim. The sooner these resuscitation efforts begin, the better the victim's chances of survival. These efforts are expensive and have a limited success rate, and cardiac arrest, among other conditions, continues to claim the lives of victims.

<CIT> discloses "a portable apparatus for electro-stimulation of the human body, said apparatus having a signal generator for generating electrical signals having waveforms suited for electro-stimulation of a part of the human body, a pair of electrodes for applying the electrical signals to the human body, a reservoir for containing conductive gel, a pump hydraulically connected to the reservoir for delivering the conductive gel, and an outer shell made of plastic material having a main body and a head that can be removed from a position of coupling to the main body". <CIT> discloses "a signal processing method and system that combines multiscale decomposition, such as wavelet, pre-processing together with a compression technique, such as an auto-associative artificial neural network, operating in the multiscale decomposition domain for signal denoising and extraction". <CIT> discloses "a signal processing method and system for the extraction of signals of unknown or unspecified form or features with severe noise corruption, such as MEG or EEG signals".

The present invention comprises an electrode system for deploying a conductive gel in an external medical device and a wearable medical device comprising the electrode system as defined in the claims.

The following paragraphs disclose examples that are not replicated in the claims but are useful for understanding the invention.

In accordance with an example there is provided an electrode system. The electrode system comprises a gel deployment receptacle configured to release a conductive gel onto a body of a subject and a fluid pressure source in fluid communication with the gel deployment receptacle.

In some examples, the electrode system is capable of delivering a defibrillation current. The electrode system may be disposed within a wearable defibrillator device. The conductive gel may be capable of conducting a defibrillation current.

In some examples, the fluid pump receives a fluid at a first pressure and outputs the fluid at a second pressure higher than the first pressure. The fluid pump may be an air pump. The second pressure may be between about 69kPa (<NUM> psig) and about <NUM> kPa (<NUM> psig).

In some examples, the gel chamber is defined on a first side of the shell. The plurality of apertures may include a plurality of shell apertures defined in a second side of the shell.

In some examples, the electrode system further comprises a gel conduit in fluid communication with the gel chamber and the plurality of shell apertures.

In some examples, the fluid inlet is in fluid communication with an internal volume of the gel chamber and an external surface of the bladder.

In some examples, the gel conduit is in fluid communication with the bladder.

In some examples, the electrode system further comprises a seal disposed at an opening in the bladder.

In some examples, the bladder is disposed proximate a first end of the shell and the gel conduit extends from the bladder in a direction toward a second end of the shell.

In some examples, the electrode system further comprises a seal disposed within the gel conduit.

In some examples, the electrode system further comprises a seal disposed between the bladder and the plurality of shell apertures.

In some examples, the plurality of shell apertures comprises at least one first shell aperture disposed at a first distance from the bladder and at least one second shell aperture disposed at a second distance from the bladder, the second distance being greater than the first distance. A cross-sectional area of the at least one second shell aperture may be greater than a cross-sectional area of the at least one first shell aperture.

In some examples, the plurality of shell apertures comprises a first pair of shell apertures, each of the first pair of shell apertures being disposed at the first distance from the bladder and having a same cross-sectional area.

In some examples, the plurality of shell apertures comprises a plurality of pairs of shell apertures disposed along a length of the gel conduit, each shell aperture of a respective pair of shell apertures disposed at a same distance from the bladder and having a same cross-sectional area, each respective pair of shell apertures being disposed at a different distance from the bladder than each other pair of shell apertures. A cross-sectional area of each shell aperture of the respective pairs of shell apertures may increase with an increased distance from the bladder.

In some examples, the gel conduit comprises a trunk and a plurality of pairs of branches extending from the trunk, each of the plurality of pairs of branches providing fluid communication between the trunk and one of the plurality of shell apertures. Each of the branches may have a cross-sectional area approximately equal to a cross-sectional area of the shell aperture with which the branch is in fluid communication. The trunk may comprise a cross-sectional area approximately equal to a sum of the cross-sectional areas of the plurality of branches.

In some examples, the seal is configured to rupture responsive to a pressure of a fluid received at the fluid inlet.

In some examples, the electrode system is configured to dispense the conductive gel, responsive to a pressure of a fluid received at the fluid inlet, through the gel conduit and through the plurality of shell apertures.

In some examples, cross-sectional areas of the plurality of shell apertures vary along a length of the gel conduit.

In some examples, cross-sectional areas of the plurality of shell apertures vary along a length of the gel conduit to cause a flow rate of the conductive gel through each of the plurality of shell apertures to be within about <NUM>% of another of the plurality of shell apertures. The plurality of shell apertures may be configured to distribute the conductive gel evenly over the second side of the shell. The plurality of shell apertures may be configured to distribute the conductive gel evenly over a conductive layer disposed on the second side of the shell.

In some examples, the fluid pump is disposed on the shell and in fluid communication with the fluid inlet.

In some examples, the electrode system further comprises a conductive layer disposed proximate to the second side of the shell.

In some examples, the electrode system further comprises a plurality of conductive layer apertures defined in the conductive layer, each respective conductive layer aperture circumscribing a respective shell aperture of the plurality of shell apertures.

In some examples, the electrode system further comprises a plurality of conductive layer apertures defined in the conductive layer, a cross-sectional area of each of the plurality of conductive layer apertures being greater than a corresponding cross-sectional area of each of the plurality of shell apertures.

In some examples, the electrode system is disposed in a garment including a monitor, the monitor in communication with at least one electrical component of the electrode system. The monitor may be in communication with the at least one electrical component of the electrode system by an inductive coupling system including a first coil disposed on the electrode system and a second coil disposed in the garment. The monitor may be in communication with the at least one electrical component of the electrode system by a capacitive coupling system including a first conductive plate or sheet disposed on the electrode system and a second conductive plate or sheet disposed in the garment. The monitor may be in communication with the at least one electrical component of the electrode system by an infrared signal communication system.

In some examples, the monitor is in communication with the at least one electrical component of the electrode system by conductive hook and loop fasteners. The conductive hook and loop fasteners may maintain the electrode system in a desired orientation relative to the garment.

In some examples, the monitor is in communication with the at least one electrical component of the electrode system by conductive snaps. The conductive snaps may maintain the electrode system in a desired orientation relative to the garment.

In some examples, the monitor is in communication with the at least one electrical component of the electrode system by one or more conductive magnets and associated conductive magnetic contacts. The one or more conductive magnets and associated conductive magnetic contacts may maintain the electrode system in a desired orientation relative to the garment.

In some examples, the electrode system further comprises a plurality of therapy electrodes each including a gel chamber and a fluid inlet in communication with the gel chamber and a common distribution node. The fluid pump is disposed on the common distribution node and in fluid communication with the fluid inlet of each of the plurality of therapy electrodes.

In some examples, the electrode system further comprises a plurality of therapy electrodes each including a gel chamber and a fluid inlet in communication with the gel chamber and a fluid pump disposed on each of the plurality of therapy electrodes and in fluid communication with the fluid inlet of the therapy electrode on which it is disposed.

In some examples, the electrode system further comprises a plurality of therapy electrodes including a first therapy electrode, a second therapy electrode, and a third therapy electrode, each of the plurality of therapy electrodes including a gel chamber and a fluid inlet in communication with the gel chamber, a first fluid pump source disposed on a first therapy electrode and in fluid communication with the fluid inlet of the first therapy electrode, and a second fluid pump disposed on the second therapy electrode and in fluid communication with the fluid inlet of the second therapy electrode and the fluid inlet of the third therapy electrode.

In some examples, the electrode system further comprises a plurality of therapy electrodes including a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, each of the plurality of therapy electrodes including a gel chamber and a fluid inlet in communication with the gel chamber, a first fluid pump disposed on the front therapy electrode and in fluid communication with the fluid inlet of the front therapy electrode, and a second fluid pump disposed on the rear therapy electrode and in fluid communication with the fluid inlet of the rear therapy electrode.

In some examples, the electrode system further comprises a plurality of therapy electrodes including a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, each of the plurality of therapy electrodes including a gel chamber and a fluid inlet in communication with the gel chamber, and a common distribution node. The fluid pump is disposed on the common distribution node and is in fluid communication with the fluid inlet of both the front therapy electrode and the rear therapy electrode.

In some examples, the electrode system further comprises a plurality of therapy electrodes including a first therapy electrode, a second therapy electrode, and a third therapy electrode, and a monitor configured to monitor a physiological parameter of a subject utilizing the therapy electrode system. The fluid pump is disposed on the monitor and is in fluid communication with each therapy electrode of the plurality of therapy electrodes through the common distribution node.

In some examples, the electrode system further comprises a plurality of therapy electrodes including a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, and a monitor configured to monitor a physiological parameter of a subject utilizing the therapy electrode system. The fluid pump is disposed on the monitor and is in fluid communication with the front therapy electrode and the rear therapy electrode through the common distribution node.

In accordance with another aspect disclosed herein there is provided an electrode system. The electrode system comprises a plurality of therapy electrodes. Each of the plurality of therapy electrodes includes a shell defining a gel chamber on a first side of the shell, a bladder disposed within the gel chamber and housing a conductive gel, a fluid inlet in fluid communication with an internal volume of the gel chamber and an external surface of the bladder, a plurality of shell apertures defined in a second side of the shell, and a gel conduit in fluid communication with the bladder and the plurality of shell apertures. The electrode system further comprises a common distribution node. Each of the plurality of therapy electrodes is at least one of fluidly connected to the common distribution node and electrically connected to the common distribution node.

In some examples, the electrode system further comprises a fluid pressure source disposed on the common distribution node, the fluid pressure source in fluid communication with the fluid inlet of each of the plurality of therapy electrodes.

In some examples, the electrode system further comprises a fluid pump disposed on each of the plurality of therapy electrodes and in fluid communication with the fluid inlet of the therapy electrode on which it is disposed.

In some examples, the plurality of therapy electrodes comprises three therapy electrodes including a first therapy electrode, a second therapy electrode, and a third therapy electrode, and the therapy electrode system further comprises a first fluid pump disposed on the first therapy electrode and in fluid communication with the fluid inlet of the first therapy electrode, and a second fluid pump disposed on the second therapy electrode and in fluid communication with the fluid inlet of the second therapy electrode and the fluid inlet of the third therapy electrode.

In some examples, the plurality of therapy electrodes comprises a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, and the therapy electrode system further comprises a first fluid pump disposed on the front therapy electrode and in fluid communication with the fluid inlet of the front therapy electrode, and a second fluid pump disposed on the rear therapy electrode and in fluid communication with the fluid inlet of the rear therapy electrode.

In some examples, the plurality of therapy electrodes comprises a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, and the therapy electrode system further comprises a fluid pressure source disposed on the common distribution node, the fluid pressure source in fluid communication with the fluid inlet of both the front therapy electrode and the rear therapy electrode.

In some examples, the plurality of therapy electrodes includes a first therapy electrode, a second therapy electrode, and a third therapy electrode, and the therapy electrode system further comprises a monitor configured to monitor a physiological parameter of a subject utilizing the therapy electrode system and a fluid pressure source disposed on the monitor and in fluid communication with the three therapy electrodes through the common distribution node.

In some examples, the plurality of therapy electrodes comprises a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration, and the therapy electrode system further comprises a monitor configured to monitor a physiological parameter of a subject utilizing the therapy electrode system and a fluid pressure source disposed on the monitor and in fluid communication with the front therapy electrode and the rear therapy electrode through the common distribution node.

In accordance with another aspect disclosed herein, there is provided a wearable monitoring device. The wearable monitoring device comprises a monitor configured to monitor a physiological parameter of a subject utilizing the wearable monitoring device, a gel chamber included in the monitor, a bladder disposed within the gel chamber and housing a conductive gel, a fluid pressure source in fluid communication with an internal volume of the gel chamber and an external surface of the bladder, and a plurality of therapy electrodes. Each of the plurality of therapy electrodes includes an electrode shell, a plurality of shell apertures defined in a side of the shell, and a gel conduit in fluid communication with the bladder and the plurality of shell apertures. The wearable monitoring device further comprises a common distribution node, each of the plurality of therapy electrodes being at least one of fluidly connected to the common distribution node and electrically connected to the common distribution node.

In some examples, the fluid pressure source is disposed in the monitor. The plurality of therapy electrodes may include a first therapy electrode, a second therapy electrode, and a third therapy electrode. The fluid pressure source may be in fluid communication with the three therapy electrodes through the common distribution node. The plurality of therapy electrodes may include a front therapy electrode having a first configuration and a rear therapy electrode having a second configuration different from the first configuration. The fluid pressure source may be in fluid communication with the fluid conduit of both the front therapy electrode and the rear therapy electrode.

We further disclose an electrode system. The electrode system comprises a shell defining a gel chamber housing a conductive gel, a fluid inlet in fluid communication with the gel chamber, and a plurality of apertures in fluid communication with the gel chamber.

Aspects and embodiments described herein are not limited in their application to the details of construction and the arrangement of components set forth in the description or illustrated in the drawings. Aspects and embodiments disclosed herein are capable of being practiced or of being carried out in various ways. The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein, is meant to encompass the items listed thereafter, equivalents thereof, and additional items, as well as alternate embodiments consisting of the items listed thereafter exclusively.

Various aspects and embodiments are directed to systems and methods for deploying a conductive gel in an external medical device. For example, such an external medical device can be an ambulatory monitoring and/or treatment device such as a wearable therapeutic device. The wearable therapeutic device can include monitoring electrodes, a therapy controller and a plurality of therapy electrodes configured to deliver electrical therapy, such as one or more defibrillation shocks or pacing pulses to a subject. For example, the external medical device may be a wearable therapeutic device such as the LifeVest® wearable cardioverter defibrillator available from ZOLL Medical Corporation of Chelmsford, Massachusetts. In other examples, the external medical device may be a stationary device that may be utilized, for example, in a hospital setting or an automated external defibrillator (AED).

The external medical device can be configured to house at least one receptacle including conductive gel. For example, the receptacle may be housed within at least one therapy electrode in the device. In an example, the receptacle may be removable or separable from the at least one therapy electrode for replacement by a patient or service personnel. Prior to delivering an electric shock, a gel deployment control unit can direct the at least one receptacle to release the conductive gel onto the plurality of therapy electrodes, lowering an impedance between the subject's skin and the therapy electrodes. In some examples described herein, the control unit can actuate a fluid pump that in turn can cause the at least one receptacle to release the conductive gel. After the conductive gel is deployed, the therapy controller can administer an electric shock or pacing pulse to the subject via the therapy electrodes and conductive gel. The therapy electrodes can be housed in or on a garment of the external medical device.

In one example, spent receptacles can be removed from the external medical device and replaced with fresh receptacles that contain at least one dose of conductive gel. For example, the spent receptacles can be replaced when the external medical device is returned to a service center for servicing and/or refurbishing.

<FIG> is a schematic diagram of an external medical device <NUM> in accordance with an embodiment. In one embodiment, external medical device <NUM> includes a garment <NUM>. Garment <NUM> may be similar to the garment disclosed in commonly owned <CIT>, or in commonly owned <CIT>.

In one embodiment garment <NUM> includes a belt <NUM>. Belt <NUM> may be worn about a subject's waist, at a higher location about the subject's chest, or at other locations between the subject's waist and shoulders. Components of external medical device <NUM> can be worn under, over, or partially under and partially over a subject's clothes.

The external medical device <NUM> includes the following elements: garment <NUM>, including belt <NUM>, therapy controller <NUM>, alarm module <NUM>, monitor <NUM>, gel deployment control unit <NUM>, first therapy electrode <NUM>, second therapy electrode <NUM>, receptacles <NUM> in or proximate each of the therapy electrodes <NUM>, <NUM>, one or more cardiac sensing electrodes <NUM>, which may each also include or be disposed proximate a receptacle <NUM> (as shown in dotted lines), shoulder strap <NUM>, and holster <NUM>. First therapy electrode <NUM> may include at least one front therapy electrode and second therapy electrode <NUM> may include at least one rear therapy electrode. In one embodiment, at least one of therapy controller <NUM>, alarm module <NUM>, monitor <NUM>, gel deployment control unit <NUM>, at least one front therapy electrode <NUM>, at least one rear therapy electrode <NUM>, receptacle <NUM>, at least one sensing electrode <NUM>, shoulder strap <NUM>, and/or holster <NUM> can be included in or attached to belt <NUM>. In an implementation, the at least one rear therapy electrode <NUM> can further include at least two rear therapy electrodes as shown in <FIG>. In some examples, at least one of alarm module <NUM> and monitor <NUM> can be fitted to open or closed pockets of belt <NUM> or garment <NUM> or otherwise attached to belt <NUM> or garment <NUM> via buttons, hook and loop fasteners, straps, snaps, magnets, or sleeves, or another attachment mechanism that forms part of belt <NUM> or garment <NUM>. These elements may also be integrated into belt <NUM> or garment <NUM>, and as such, may be a permanent part of belt <NUM> or garment <NUM>. In some examples, the alarm module <NUM> can be integrated into and a part of the monitor <NUM>. External medical device <NUM> may include the above mentioned elements, as well as additional elements.

<FIG> is an illustration of an embodiment of the external medical device <NUM> with the electrode components shown removed from the garment. As depicted in <FIG>, the therapy controller <NUM>, the alarm module <NUM>, and the monitor <NUM> can be integrated into a portable medical device control unit <NUM> that can be attached to the garment <NUM>.

Therapy controller <NUM> is included in garment <NUM>. Therapy controller <NUM> can be attached to shoulder strap <NUM>, or disposed in holster <NUM>. Holster <NUM> may attach to or be part of garment <NUM>, shoulder strap <NUM>, or belt <NUM>. In some implementations, therapy controller <NUM>, alarm module <NUM>, and monitor <NUM> are combined into a single medical device control unit <NUM> that may be attached to or carried in the garment <NUM>. Therapy controller <NUM> is electrically coupled to first therapy electrode <NUM> and second therapy electrode <NUM>. In some embodiments, therapy controller <NUM> is also electrically coupled to one or more sensing electrodes <NUM>. Each of electrodes <NUM>, <NUM> has an associated receptacle <NUM>. In one embodiment, therapy controller <NUM> may include the defibrillator described in commonly owned <CIT>.

Monitor <NUM> or control circuitry of therapy controller <NUM> monitors a subject's condition. For example, the one or more sensing electrodes <NUM> can sense electrical activity of the subject's heart signals. When an arrhythmic event is detected, alarm module <NUM> sounds a warning that the subject wearing external medical device <NUM> is in danger of, or is experiencing, a heart attack, cardiac arrest, or other form of cardiac distress. This warning may be audio, visual, haptic (e.g., vibrating alarm module <NUM>) or combinations thereof. The signals sensed by the one or more sensing electrodes <NUM> can be displayed as electrocardiograph signals on monitor <NUM>. This and other information can be stored in memory units associated with monitor <NUM> or therapy controller <NUM> for analysis by a doctor, rescuer, or health care provider.

Alarm module <NUM> may provide an alarm that indicates that the subject will receive a defibrillation shock from therapy controller <NUM> delivered by the first therapy electrode <NUM> and second therapy electrode <NUM> unless the subject wearing external medical device <NUM> takes some action to prevent therapy controller <NUM> from applying the shock. For example, alarm module <NUM> or monitor <NUM> may include a user interface having at least one button or touch screen. In this example, the subject can depress the at least one button to indicate that the subject is conscious. In this example, the defibrillation shock will not be applied while the subject depresses the at least one button for a sufficient amount of time, or if control logic of therapy controller <NUM> determines that the electrical heart activity of the subject (as detected by sensing electrode <NUM>) has returned to normal. Continuing with this example, if the subject loses consciousness, the subject will release the at least one button and therapy controller <NUM> will apply a defibrillation shock via the first therapy electrode <NUM> and second therapy electrode <NUM>.

First therapy electrode <NUM> includes at least one front therapy electrode positioned in garment <NUM> in front (e.g., anterior or about the chest) of the subject, and second therapy electrode <NUM> includes at least one therapy electrode positioned in garment <NUM> at the rear (e.g. posterior or about the back) of the subject. Other anterior, posterior, and lateral positioning with respect to the subject when the subject is wearing garment <NUM> is possible. For example, first therapy electrode <NUM> and second therapy electrode <NUM> may both be in an anterior position with respect to the subject. In one embodiment, multiple therapy electrodes are disposed in an anterior position. Multiple therapy electrodes may also be disposed in any position, e.g., anterior, posterior, or lateral.

In one embodiment, first therapy electrode <NUM> and second therapy electrode <NUM> may be permanent components of external medical device <NUM>. Electrodes <NUM> and <NUM> can be housed anywhere in garment <NUM>. For example, first therapy electrode <NUM> can be integral to garment <NUM> and disposed proximate to the subject's chest or abdomen when the subject is wearing external medical device <NUM>. Second therapy electrode <NUM> can be integral to garment <NUM> and disposed proximate to the subject's back when the subject is wearing external medical device <NUM>. In one embodiment, when a shock is applied, first therapy electrode <NUM>, second therapy electrode <NUM>, the subject's body, and therapy controller <NUM> form at least part of a current path for the shock. In some embodiments, for example, as illustrated in <FIG>, electrodes <NUM>, <NUM>, and <NUM> may be coupled to a common distribution node <NUM>, described in more detail below. An electrical connector <NUM> may electrically connect the common distribution node <NUM> to a monitor <NUM>.

An example receptacle <NUM> that can be used with embodiments of the external medical device <NUM> is shown in <FIG>. A person of ordinary skill in the art will appreciate that the example receptacle <NUM> shown in <FIG> is for illustration only and does not limit the claims. For example, receptacle <NUM> can include a shell <NUM> (see <FIG>) having an upper portion defining an upper surface <NUM> of the receptacle <NUM> and a lower portion defining a lower surface <NUM> of the receptacle <NUM>. In some embodiments, such as illustrated in <FIG>, the lower surface <NUM> can be at least partially covered with a conductive layer <NUM> to form a therapy electrode (e.g., for use as one of therapy electrodes <NUM>, <NUM>). The conductive layer <NUM> can be formed from, for example, a layer of metal adhered to the lower surface <NUM>. The layer of metal may include, for example, tin, silver, stainless steel, or other metals, metal oxides, or mixtures thereof. In some embodiments, the layer of metal may be replaced or supplemented with a nonmetallic conductive material, for example, a conductive polymer, carbon fiber, a material including conductive particles dispersed in it, or any other material that is electrically conductive and that may also be biocompatible and/or corrosion resistant.

In some examples, the receptacle <NUM> and conductive layer <NUM> can form a monitoring/sensing electrode for detecting a signal (e.g., a cardiac signal) from the patient. In some examples, the receptacle <NUM> can include one or more conductive layers and/or sensors for performing both monitoring/sensing a patient signal and providing a therapeutic treatment.

One or more electrical connectors (not shown) can electrically connect the conductive layer <NUM> to the therapy controller <NUM> to enable it to function as one of the therapy electrodes <NUM>, <NUM> of embodiments of the external medical device disclosed herein. In other embodiments, the receptacle <NUM> may not include conductive layer <NUM> and the receptacle <NUM> may be configured to dispense conductive gel onto or proximate to a therapy electrode that is formed separately from the receptacle <NUM>. In some embodiments, the receptacle <NUM> may be removably attached to the therapy electrode <NUM>, <NUM> (e.g., by being at least removably attached to the conductive layer <NUM>).

In one example, a gel chamber <NUM> can be defined in an upper portion of the shell of the receptacle <NUM> for containing the conductive gel (not shown). In use, when a defibrillation shock is to be applied to a subject wearing a wearable therapeutic device including the receptacle <NUM>, an external pressure can be applied to the conductive gel through the use of an external pressure source or a pressure source device. For example, the pressure can be applied to the internal volume of the gel chamber <NUM>. In some implementations, the pressure source can be a fluid pump (e.g., an air pump) as described in further detail below. For example, the fluid can be physically separated from the conductive gel by a membrane such that pressure applied by the fluid on one side of the membrane can cause the conductive gel that is disposed on the other side of the membrane to be deployed.

In some implementations, the conductive gel can be contained within a bladder <NUM> (see <FIG>) disposed within the gel chamber <NUM>. In some examples, the gel chamber <NUM> and/or the bladder <NUM> can include a mechanism for separating the gel from the rest of the delivery system (e.g., the gel conduit <NUM>) that can be configured to allow a flow of the gel from the gel chamber and/or bladder <NUM> once a pressure threshold is reached or exceeded as described below. For example, such a mechanism can include a seal <NUM>. The pressure can build up in the gel chamber <NUM> and can cause the seal <NUM> to rupture at, for example, about <NUM> kPa (<NUM> psig). In some examples, the seal can be configured to release the gel at any pressure value in a range of <NUM> - <NUM> kPa (<NUM>-<NUM> psig). A person of ordinary skill in the art will recognize that the range of values provided herein is for illustration only and, in some examples, values above or below this range may be used. For example, the pressure range can be increased to a range of <NUM>-<NUM> kPa (<NUM>-<NUM> psig) and still be in accordance with the concepts described herein. Further, while seal <NUM> is shown to be disposed at a location between gel chamber <NUM> and a gel conduit <NUM>, it should be understood that seal <NUM> can be placed anywhere within gel conduit <NUM> on or in the receptacle <NUM>, for example, defined in the top portion of the receptacle <NUM> as shown in <FIG>, and/or within the gel chamber <NUM> and/or on the bladder <NUM>.

When seal <NUM> ruptures, the conductive gel contained within bladder <NUM> flows through a main trunk <NUM> of the gel conduit <NUM>, through branches <NUM> of the gel conduit <NUM>, and through shell apertures <NUM> defined in the lower portion of the shell to provide a conductive path between a therapy electrode <NUM>, <NUM> and a body of a subject wearing the external medical device <NUM>. In some examples, the external pressure source can cause pressure to be applied for a predetermined duration to reach the threshold (e.g., <NUM>-<NUM> kPa (<NUM>-<NUM> psig)) necessary for causing the seal <NUM> to rupture and further ensuring that substantially all or at least a significant amount of the conductive gel is deployed. In some embodiments, the pressure can be applied until all conductive gel from the gel chamber <NUM> and/or bladder <NUM> is dispensed through the shell apertures <NUM>. For example, depending on a location of the pressure source, the pressure can be applied for approximately <NUM> seconds (generally in a range of <NUM>-<NUM> seconds) before the pressure source is turned off. In some examples, a sensing circuit (as described below) can detect if a desired impedance value is reached and cause the pressure source device to be turned off responsive to the desired impedance value having been reached.

In other embodiments, some conductive gel may remain, for example, within one or more portions of the gel conduit <NUM> after the receptacle <NUM> is activated to dispense the conductive gel.

In some embodiments, the bladder <NUM> is not included within the gel chamber <NUM> and the conductive gel may be disposed in direct contact with internal surfaces of the gel chamber <NUM>. As such, the fluid from the fluid pump may directly contact the conductive gel. In other embodiments, the gel chamber <NUM> need not be defined in the upper portion of the shell of the receptacle <NUM>. For example, the gel chamber <NUM> may straddle the upper and lower portions of the shell. In other embodiments, the gel chamber <NUM> need not even be defined on or in the shell of the receptacle <NUM>, but may be disposed separate from the receptacle <NUM>, for example, on a separate receptacle <NUM> or on or in another component of the external medical device <NUM>. In some examples, the bladder <NUM> may be only partially disposed within the gel chamber <NUM> (or even the receptacle <NUM>) and as such a portion of the bladder <NUM> may be disposed external to the gel chamber <NUM> (or receptacle <NUM>).

A source of the external pressure that is applied to bladder <NUM> within gel chamber <NUM> may be a gas cartridge as disclosed in commonly owned <CIT>. Alternatively, the source of pressure can be a fluid pump <NUM> (see <FIG>) which may be disposed to be either part of the therapy electrode <NUM>, <NUM>, or to be external to the receptacle <NUM>, for example, disposed on or in the monitor <NUM> or on another portion of the belt <NUM> or garment <NUM> as described further below. For example, the fluid pump can be implemented within or in the form of a removable cartridge. After the gel is deployed, the spent cartridge can be removed and replaced with a new cartridge.

In some embodiments, the fluid pump <NUM> is an air pump. The fluid pump <NUM> may receive or intake a fluid, for example, air, at a first pressure and output the fluid at a second pressure higher than the first pressure by, for example, between about <NUM> kPa gauge (about <NUM> psig) and about <NUM> kPa gauge (about <NUM> psig). In some embodiments, the fluid pump <NUM> may include a model KPM27H miniature air pump, or one of the other miniature air pumps available from Koge Electronics Co. The fluid pump <NUM> may have dimensions of about <NUM> in x <NUM> in x <NUM> in (<NUM> x <NUM> x <NUM>). The fluid pump <NUM> utilized in embodiments disclosed herein, however, is not limited to a KPM27H miniature air pump. Any fluid or air pressure pump capable of providing sufficient pressure to cause release of the conductive gel from a receptacle <NUM> may be utilized.

The fluid pump <NUM> provides pressurized fluid, for example, air to the internal volume of the gel chamber <NUM> and/or to an external surface of the bladder <NUM> within the gel chamber <NUM> through a fluid conduit or tube fluidly connecting an output of the fluid pump <NUM> with a fluid inlet <NUM> disposed on the receptacle <NUM>, for example, on the upper portion of the receptacle <NUM> as shown in <FIG>. In some embodiments an intermediate chamber or conduit may be provided between the fluid pump <NUM> and fluid inlet <NUM> and/or between the fluid inlet <NUM> and the gel chamber <NUM>. The fluid pump <NUM>, in some embodiments, provides a pressure of between about <NUM> kPa (<NUM> psig) and about <NUM> kPa (<NUM> psig) to the internal volume of the gel chamber <NUM> and/or external surface of the bladder <NUM>. As detailed above, this pressure range can be varied to be higher or lower than <NUM>-<NUM> psig. For instance, the range can be selected to be <NUM>-<NUM> kPa (<NUM>-<NUM> psig).

In some examples, the source of external pressure (the "fluid pressure source") can be in the form of a plunger mechanism disposed within a barrel (e.g., cylindrical or any other shape), such as in a syringe. In such cases, the conductive gel can be disposed within the barrel (or tube). When the plunger is actuated, e.g., by a mechanism activated in accordance with the principles described herein, the gel can be expelled from within the barrel or tube. For example, a seal can be placed over an orifice at an open end of the tube. When the plunger is actuated, the seal can be ruptured as described herein, and the conductive gel can be released. For example, a syringe pump can be activated to release conductive gel in accordance with the concepts described herein.

In some examples, a different fluid can be disposed within the barrel to serve as a working fluid in applying pressure directly or indirectly to the conductive gel. For example, the conductive gel can be disposed within a bladder (such as bladder <NUM>). The working fluid can be expelled via the orifice in the syringe such that the resultant pressure is applied directly to the conductive gel or, e.g., through a wall of the bladder <NUM>, if the gel is disposed within the bladder <NUM>.

For example, the syringe pump can be implemented within or in the form of a removable cartridge. After the gel is deployed, the spent cartridge can be removed and replaced with a new cartridge.

In some implementations, the external pressure source can be a peristaltic pump. For example, such a pump can include a rotary mechanism having rollers (or "lobes") for compressing or pinching closed a flexible, circular tube inside a circular pump casing. In some examples, apart from or in addition to a circular peristaltic pump, a linear peristaltic pump can be employed for a same or similar effect. In some examples, the fluid in the pump can be the conductive gel. In other examples, the fluid can be a working fluid which can be used to apply pressure directly or indirectly to the conductive gel in accordance with the principles described herein. For example, the peristaltic pump can be implemented within or in the form of a removable cartridge. After the gel is deployed, the spent cartridge can be removed and replaced with a new cartridge.

In some embodiments, the receptacle <NUM> includes a plurality of shell apertures <NUM>. For example, the apertures <NUM> can be sized and spatially distributed to cause the gel to be substantially evenly distributed over the area of contact of the therapy electrode with the patient's skin. An example of such sizing and spacing is shown below. It should be understood, however, that other patterns and/or distributions of shell apertures <NUM> can be used to similarly result in a substantially even distribution of the conductive gel.

For example, the receptacle <NUM> illustrated in <FIG> includes ten shell apertures <NUM>. More or fewer shell apertures <NUM> may be provided. As shown in <FIG> the shell apertures <NUM> may be arranged in pairs, specifically, five pairs of shell apertures <NUM>.

As shown, each shell aperture <NUM> in a pair of shell apertures <NUM> is disposed at a common distance from a first end <NUM>' and second end <NUM>'' of the receptacle and from the gel chamber <NUM> and/or bladder <NUM>. Each shell aperture <NUM> in a pair of shell apertures <NUM> has a common length and/or volume of gel conduit <NUM> between the shell aperture <NUM> and the gel chamber <NUM> and/or bladder <NUM>.

The shell apertures <NUM> are sized such that upon dispensing of the conductive gel from the receptacle <NUM>, a substantially same amount of conductive gel flows through each of the shell apertures <NUM>. For example, in some embodiments, the shell apertures <NUM> are sized such that upon dispensing of the conductive gel from the receptacle <NUM> a rate and/or an amount of gel dispensed through any shell aperture <NUM> is between about <NUM>% and <NUM>%, for example, within about <NUM>%, of a rate and/or amount of conductive gel dispensed through any other of the shell apertures <NUM>. To accomplish this, the shell apertures <NUM> may be configured to increase in cross-sectional area or diameter with increasing distance from the gel chamber <NUM> and/or bladder <NUM>. In some implementations, each shell aperture <NUM> in a pair of shell apertures <NUM> located at a same or similar distance from the gel chamber <NUM> and/or bladder <NUM> may have a same or similar cross-sectional area or diameter. For example, in some cases, each aperture in a pair of apertures <NUM> may have a cross-sectional area that is within about <NUM>% of a cross-sectional area of the other aperture in the pair of apertures <NUM>.

In a specific, non-limiting example, the shell apertures 1180A closest to the gel chamber <NUM> and/or bladder <NUM> have a diameter of about <NUM> inches (<NUM>) and the shell apertures 1180B furthest from the gel chamber <NUM> and/or bladder <NUM> have a diameter of about <NUM> inches (<NUM>). The branches <NUM> of the gel conduit <NUM> have similar or the same cross-sectional areas as the respective shell apertures <NUM> at which they terminate and thus, as shown in <FIG>, the cross-sectional area of the branches <NUM> increase with increasing distance from the gel chamber <NUM> and/or bladder <NUM>. The main trunk <NUM> of the gel conduit <NUM> has a cross-sectional area about equal to the sum of the cross-sectional areas of each of the branches <NUM>.

In embodiments of receptacles <NUM> including a conductive layer <NUM>, the conductive layer <NUM> includes a plurality of conductive layer apertures <NUM> corresponding to the shell apertures <NUM>. In some implementations, there may be a one-to-one correspondence between shell apertures <NUM> and conductive layer apertures <NUM>. For example, each conductive layer aperture <NUM> circumscribes a single shell aperture <NUM>. Each conductive layer apertures <NUM> has a diameter and/or cross-sectional area greater than that of the shell aperture <NUM> that it circumscribes so as not to interfere with the passage of conductive gel through the shell aperture <NUM>. In some embodiments, each conductive layer aperture <NUM> has a similar or same diameter and/or cross-sectional area as each other conductive layer aperture <NUM>.

In some implementations, the gel deployment apparatus can include a plurality of tubes (or a single main tube comprises a plurality of branch tubes) disposed on a flexible frame in a predetermined arrangement. For example, the one or more tubes can be arranged to carry conductive gel from a gel chamber (e.g., located in the monitor) and dispense the gel substantially evenly over a surface of the patient's skin that is in contact with a conductive surface of a therapy electrode. For example, the tubes can be configured to be distributed in the form of pairs of tubes branching out on either side of a central line of the frame (e.g., in a manner similar to the arrangement shown for <FIG>). For example, the plurality of tubes can comprise five or more pairs of tubes arranged to be distributed along a length of the frame. In some implementations, a cross-sectional area or a diameter of the tubes can vary in a similar manner as described above.

For example, tubes may be sized such that upon dispensing of the conductive gel, a substantially same amount of conductive gel flows through each of the tubes. For example, in some embodiments, the tubes may be sized such that upon dispensing of the conductive gel a rate and/or an amount of gel dispensed through any tube is between about <NUM>% and <NUM>%, for example, within about <NUM>%, of a rate and/or amount of conductive gel dispensed through any other tube. To accomplish this, tubes may be configured to increase in cross-sectional area or diameter with increasing distance from a gel chamber. In some implementations, each tube in a pair of tubes located at a same or similar distance from a gel chamber may have a same or similar cross-sectional area or diameter. For example, in some cases, each tube in a pair of tubes may have a cross-sectional area that is within about <NUM>% of a cross-sectional area of the other tube in the pair of tubes.

In some examples, the gel chamber in communication with the tubes (along with the tubes and the associated gel deployment circuitry) can be implemented within or in the form of a removable cartridge that is disposed within any of the monitor, distribution node, and/or one or more electrodes. In some implementations, only the gel chamber may be within the removable cartridge so that the associated gel deployment circuitry can be reused and not discarded. After the gel is deployed, the spent cartridge can be removed and replaced with a new cartridge.

In an embodiment, for example, as illustrated in <FIG>, a pressure source (e.g., fluid pump <NUM>) is incorporated on one or more of the therapy electrodes <NUM>, <NUM> themselves (rather than in, e.g., the distribution node or the monitor). It should be understood that any other pressure sources and/or mechanisms described above may be used (e.g., a syringe or a peristaltic pump).

Fluid pump <NUM> can be coupled to or mounted on a portion of the receptacle <NUM>, for example, on the upper surface <NUM> of the receptacle <NUM> or an extension thereof. The fluid pump <NUM> may be fluidly coupled by a fluid pressure conduit <NUM> to the fluid inlet <NUM> or directly to the internal volume of the gel chamber <NUM>. In some embodiments, the fluid pump <NUM> is removably coupled to the receptacle <NUM> so that the fluid pump <NUM> may be reused with a different receptacle <NUM> upon failure of a first receptacle <NUM> to which it is coupled and/or after activation of the first receptacle <NUM> if the first receptacle <NUM> is a single use receptacle <NUM>.

Receptacle <NUM> can include various sensors and/or electrical and/or electronic components for causing deployment of the conductive gel and detecting the event of gel deployment, a quantity of gel deployed, and/or a measure of a change in impedance caused by the gel deployment. For example, the receptacle <NUM> may include a gel deployment control unit <NUM> including an activator circuit <NUM>. Activator circuit <NUM> may receive an activation signal from, for example, therapy controller <NUM> or monitor <NUM> indicating that the receptacle <NUM> should release conductive gel. Responsive to receipt of the activation signal, activator circuit <NUM> may send current from, for example, a battery <NUM> located on the receptacle <NUM> or elsewhere on or in the external medical device <NUM>, to the pressure source <NUM> (e.g., the fluid pump) to pressurize the gel chamber <NUM> and/or bladder <NUM>, cause the seal <NUM> to rupture, and cause the release of conductive gel from receptacle <NUM>.

In some embodiments, receptacle <NUM> further includes a sensing circuit <NUM>. Sensing circuit <NUM> may include functionality to determine and provide an indication, for example, via monitor <NUM>, of whether the therapy electrode <NUM>, <NUM> is functional, properly connected, and/or properly aligned in garment <NUM>. For example, such a sensing circuit <NUM> can be one or more orientation circuits described in commonly owned <CIT>.

Sensing circuit <NUM> may additionally or alternatively be configured to communicate with a pressure sensor <NUM> disposed on receptacle <NUM> or external to receptacle <NUM> to make a determination as to whether portions of receptacle <NUM>, for example, gel conduit <NUM> and/or bladder <NUM> and/or gel chamber <NUM> are intact. Pressure sensor <NUM> may be configured to monitor the pressure in one or more portions of the receptacle <NUM>, for example, in the gel conduit <NUM> and/or bladder <NUM> and/or gel chamber <NUM> to monitor for faults. For example, the gel conduit <NUM> and/or bladder <NUM> and/or gel chamber <NUM> may be at least partially evacuated or pressurized. A rupture in the gel conduit <NUM> and/or bladder <NUM> and/or gel chamber <NUM> may result in a pressure change in the gel conduit <NUM> and/or bladder <NUM> and/or gel chamber <NUM> which may be sensed by the pressure sensor <NUM>. The pressure sensor <NUM> may provide an indication of the error condition to one or more other components of the wearable therapeutic device, for example, sensing circuit <NUM> and/or alarm module <NUM>, and/or monitor <NUM>. In some examples, the control unit <NUM> can determine if a receptacle <NUM> needs to be replaced, for example, if sensing circuit <NUM> receives a signal from pressure sensor <NUM> indicative of the conductive gel having been released or the gel conduit <NUM> or bladder <NUM> and/or gel chamber <NUM> having been ruptured.

In some embodiments, one or more functions of gel deployment control unit <NUM> may be alternatively be performed by a control unit <NUM> disposed external to receptacle <NUM> in a portion of the garment <NUM>, for example in monitor <NUM> or therapy controller <NUM>. For example, as illustrated in <FIG>, receptacle <NUM> may be free of electronic components but include a pressure source (e.g., fluid pump <NUM>).

Embodiments of the receptacle <NUM> may also include a connection port <NUM>. The connection port <NUM> provides for communication between electrical and/or electronic components of the receptacle <NUM>, for example, any one or more of the control unit <NUM>, sensing circuit <NUM>, activator circuit <NUM>, and pressure sensor <NUM> and components of the garment, for example, therapy controller <NUM>, alarm module <NUM> and/or monitor <NUM>. In some embodiments, power is provided through the connection port <NUM> from an external source, for example, a battery located in a portion of the garment <NUM> to power components of the receptacle <NUM> and/or charge the battery <NUM> as needed. The connection port <NUM> may include a winding of an induction coil that provides electromagnetic connection with components of the garment, for example, alarm module <NUM> and/or monitor <NUM> through a complementary winding of the induction coil disposed on or in the garment <NUM>.

In other embodiments, the connection port <NUM> may include one or more connectors, for example, one or more conductive snaps and/or conductive hook and loop fasteners and/or conductive magnets and conductive magnetic contacts having complimentary portions disposed on the receptacle <NUM> and the garment <NUM> to form an electromechanical and/or electrical connection between receptacle <NUM> and garment <NUM> and provide a communication pathway between one or more components of the receptacle <NUM> and one or more components of the garment <NUM>. The connector(s) may facilitate or further help ensure proper alignment of the receptacle <NUM> within the garment <NUM>. If the receptacle <NUM> is not properly aligned with the garment <NUM>, the connector(s) on the receptacle <NUM> will not be able to properly couple to the complementary connector(s) in the garment <NUM>, and an indicator of improper alignment may be provided, for example, via monitor <NUM>. In some embodiments, alternative or additional wired or wireless means, for example, one or more RF or infrared transmitters, receivers, or transceivers having complimentary components located in the garment <NUM> and in the receptacle <NUM> may be utilized to provide communication between one or more components of the receptacle <NUM> and one or more components of the garment <NUM>. In some embodiments, conductive plates, sheets, or films, for example, metallic plates, sheets, or films in the garment <NUM> and in the receptacle <NUM> may be utilized to provide communication via capacitive coupling between one or more components of the receptacle <NUM> and one or more components of the garment <NUM>.

In some embodiments, in addition to or as an alternative to receptacles <NUM>, external medical device <NUM> may include one or more receptacles <NUM> as disclosed in commonly owned <CIT> disposed proximate respective therapy electrodes.

In some embodiments, multiple receptacles <NUM> in embodiments of the disclosed external medical device <NUM> are coupled to one another and/or to a common distribution node by one or more signal lines and/or fluid pressure conduits and/or gel conduits. The common distribution node may be included in various portions of the garment <NUM>, for example, the monitor <NUM> or gel deployment control unit <NUM> or on one of the receptacles <NUM>, or may be a dedicated unit disposed, for example, on the belt <NUM> or other part of the garment <NUM>. The common distribution node may provide communication between the receptacles <NUM>, for example, one or more electrical or electronic components of the receptacles, and one or more components of the garment <NUM>, for example, alarm module <NUM> and/or monitor <NUM>. The signal lines can include electrical conductors electrically connected to any of the embodiments of the connection port <NUM> described above. The signal lines may be utilized to transfer communication signals between components of the external medical device and/or may be utilized to conduct current to receptacles <NUM> that are included in therapy electrodes <NUM>, <NUM> of the external medical device, for example, to deliver a defibrillation shock or pacing pulses to a subject. In embodiments where a receptacle <NUM> does not contain any electrical components and is not part of a therapy electrode, the receptacle <NUM> may not have any signal line connected to it. Features, for example, fluid pressure source(s) and/or electrical or electronic components (e.g., gel deployment control unit <NUM>, sensing circuit <NUM>, activator circuit <NUM> pressure sensor <NUM>, and/or battery <NUM>) may be shared among the multiple receptacles <NUM>.

For example, as illustrated in <FIG> a system includes two rear receptacles 1145R and one front receptacle 1145F coupled to a common distribution node <NUM> by signal lines <NUM>. Each receptacle 1145R, 1145F includes its own gel chamber <NUM> and pressure source, for example, fluid pumps <NUM>. It should be understood that in the example illustrated in <FIG> and those examples that follow the pressure source is not limited to a fluid pump <NUM>, but may be any fluid pressure source known in the art. Although illustrated as including embodiments of receptacle <NUM>, it should be appreciated that the embodiment illustrated in <FIG> as well as those illustrated in <FIG> may be implemented with one or more of receptacles <NUM> replaced with embodiments of receptacles <NUM> as disclosed in commonly owned <CIT>, including multiple doses of conductive gel. For example, as illustrated in <FIG>, the receptacles 1145R, 1145F of <FIG> may be substituted with receptacles 1146R, 1146F, respectively, which include multiple doses or reservoirs <NUM> of conductive gel. Receptacles 1146R, 1146F may be similar to embodiments of receptacles <NUM> as disclosed in commonly owned <CIT> and/or may include embodiments of gel capsules as disclosed in commonly owned <CIT>.

<FIG> illustrates a system in which each receptacle 1145R, 1145F includes its own gel chamber <NUM>, but share a common fluid pump <NUM>. The fluid pump is disposed on the common distribution node <NUM> and is in fluid communication with the gel chambers <NUM> on each receptacle 1145R, 1145F through fluid pressure conduits <NUM>. Signal lines <NUM> may also be provided, for communicating defibrillation and/or pacing pulses, as well as other electrical signals between components of the garment <NUM> and the receptacles 1145F, 1145R and/or between receptacles 1145F, 1145R and/or common distribution node <NUM>.

In the example shown in <FIG>, each receptacle 1145R, 1145F includes its own gel chamber <NUM>. The front receptacle 1145F includes its own fluid pump <NUM>. The rear receptacles 1145R share a common fluid pump <NUM> mounted on one of the rear receptacles 1145R. A fluid pressure conduit <NUM> allows for the fluid pump <NUM> to deliver pressurized air to the gel chamber <NUM> of the rear receptacle 1145R that it is not mounted on. Signal lines <NUM> provide communication between the common distribution node <NUM>, the front receptacle 1145F, and the rear receptacles 1145R.

<FIG> illustrates a system similar to <FIG>, but wherein there is no fluid pump <NUM> located on either of the rear receptacles 1145R. Rather, a single fluid pump <NUM> is provided on the front receptacle 1145F. The fluid pump <NUM> provided on the front receptacle 1145F controls release of conductive gel from each of the receptacles 1145F, 1145R. The rear receptacles 1145R may be considered "slave" receptacles controlled by front receptacle 1145F, which may be considered a "master" receptacle in the example of <FIG>. Signal lines <NUM> and fluid pressure conduits <NUM> provide electrical and fluid communication, respectfully, between the front receptacle 1145F and the rear receptacles 1145R by way of the common distribution node <NUM>.

It should be appreciated that instead of the fluid pressure conduits <NUM> and/or signal lines <NUM> being routed through the common distribution node <NUM>, the fluid pressure conduit(s) <NUM> and/or signal line(s) <NUM> from the front receptacle 1145F may be directly coupled to the fluid inlet or a signal input, respectively, of one or both of the rear receptacles 1145R.

In other embodiments, any one of the receptacles may be a "master" receptacle and the other receptacles may be "slave" receptacles. The front receptacle 1145F and two rear receptacles 1145R can be connected as a group, with one of the three of receptacles containing the fluid pump <NUM>. Two of the receptacles can be in a "slave" relationship to the receptacle containing the fluid pump <NUM> (the "master" receptacle). In some embodiments, each of the three receptacles can contain their own gel chambers <NUM>. As such, the fluid pump <NUM> can cause force fluid (e.g., air) through conduits that are in fluid connection with the gel chambers <NUM>.

In some examples, the "master" receptacle can include a gel chamber <NUM> in communication with apertures on all three receptacles. In this configuration, the gel deployment electronics as described herein can cause the fluid pump <NUM> to deploy the gel through the apertures on all three receptacles. For example, the gel chamber on the "master" receptacle can be fluidly connected through a gel conduit to the apertures of the "slave" receptacles. In this scenario, the gel can be directed from the gel chamber <NUM> on the "master" receptacle through the gel conduit and released from the apertures in each of the receptacles. In some implementations, after treatment, each of the "slave" receptacles can be user-replaceable (or replaceable during servicing), while the "master" receptacle may be retained.

In the example shown in <FIG>, the two rear receptacles 1145R shown in <FIG> have been combined into a single larger rear receptacle 1145R' with a single larger gel chamber <NUM> and the fluid pressure conduit <NUM> has been eliminated. The front receptacle 1145F includes its own gel chamber <NUM> and fluid pump <NUM>. Signal lines <NUM> provide communication between the common distribution node <NUM>, the front receptacle 1145F, and the rear receptacle 1145R'.

The example illustrated in <FIG> includes a single larger rear receptacle 1145R' and a front receptacle 1145F, each with its own gel chamber <NUM>. The receptacles 1145R' and 1145F share a common fluid pump <NUM> mounted on the common distribution node <NUM> and fluidly connected to the gel chambers <NUM> of the receptacles 1145R' and 1145F through fluid pressure conduits <NUM>. Signal lines <NUM> may also be provided for communicating defibrillation and/or pacing pulses, as well as other electrical signals, between components of the garment <NUM> and the receptacles 1145F, 1145R' and/or between receptacles 1145F, 1145R' and/or common distribution node <NUM>.

The example illustrated in <FIG> includes a single larger rear receptacle 1145R' and a front receptacle 1145F, each with its own gel chamber <NUM>. The receptacles 1145R' and 1145F share a common fluid pump <NUM> mounted on a separate component of the garment <NUM>, for example, the monitor <NUM>. The fluid pump <NUM> is fluidly connected to the gel chambers <NUM> of the receptacles 1145R' and 1145F through fluid pressure conduits <NUM> and through the common distribution node <NUM>. Signal lines <NUM> may also be provided, for communicating defibrillation and/or pacing pulses, as well as other electrical signals between components of the garment <NUM>, for example, monitor <NUM> and the receptacles 1145F, 1145R' and/or between receptacles 1145F, 1145R' and/or common distribution node <NUM>.

The example illustrated in <FIG> is similar to that illustrated in <FIG>, with the single larger rear receptacle 1145R' split into two smaller sized receptacles 1145R. A fluid pressure conduit <NUM> fluidly couples the receptacles 1145R so that pressurized air from the fluid pump <NUM> can reach the gel chambers <NUM> of both of the receptacles 1145R. Signal lines <NUM> may also be provided, for communicating defibrillation and/or pacing pulses, as well as other electrical signals between components of the garment <NUM>, for example, monitor <NUM> and the receptacles 1145F, 1145R and/or between receptacles 1145F, 1145R and/or common distribution node <NUM>.

In the example shown in <FIG>, none of the receptacles 1145F, 1145R includes its own fluid pump <NUM> or gel reservoir <NUM>. Rather, a common fluid pump <NUM> and large gel reservoir <NUM> are disposed on a separate component of the garment <NUM>, for example, the monitor <NUM>. Conductive gel is directed into each of the receptacles 1145F, 1145R from the common large gel reservoir <NUM> through gel conduits <NUM> and through the common distribution node <NUM>. Signal lines <NUM> may also be provided for communicating defibrillation and/or pacing pulses, as well as other electrical signals, between components of the garment <NUM>, for example, monitor <NUM> and the receptacles 1145F, 1145R and/or between receptacles 1145F, 1145R and/or common distribution node <NUM>.

The example shown in <FIG> is similar to that shown in <FIG>, with the two separate rear receptacles 1145R combined into a single large rear receptacle 1145R'. The fluid pressure conduit <NUM> between the two rear receptacles 1145R of <FIG> is eliminated. Signal lines <NUM> may be provided for communicating defibrillation and/or pacing pulses, as well as other electrical signals between components of the garment <NUM>, for example, monitor <NUM> and the receptacles 1145F, 1145R and/or between receptacles 1145F, 1145R and/or common distribution node <NUM>.

In one embodiment, at least one of first therapy electrode <NUM> and second therapy electrode <NUM> includes conductive thread. In one embodiment, at least one of first therapy electrode <NUM> and second therapy electrode <NUM> consists only of conductive thread. In one embodiment, at least one of first therapy electrode <NUM> and second therapy electrode <NUM> includes conductive thread as well as additional electrode components, such as a conductive element that may be stitched into garment <NUM> with the conductive thread. In such embodiments, a receptacle <NUM> that does not include a conductive layer may be associated with each therapy electrode <NUM>, <NUM> to dispense conductive gel between the electrodes <NUM>, <NUM> and the body of a subject prior to the delivery of electrical energy, for example, a defibrillation shock or pacing pulses, to the subject through the therapy electrodes.

In one embodiment, when the subject is defibrillated or paced, conductive gel released from receptacles <NUM> reduces impedance between first therapy electrode <NUM> and second therapy electrode <NUM> (or conductive thread, metallic surfaces, or combinations thereof that form a surface of electrodes <NUM>, <NUM>) and the subject's skin. The impedance reduction when conductive gel is released from receptacles <NUM> improves the efficiency of energy delivery from therapy controller <NUM> to the subject and reduces the chance of skin damage in the form of, for example, burning, reddening, or other types of irritation to the skin.

<FIG> depicts an example of conductive gel entering the area between a therapy electrode and the subject's skin. Conductive gel may also be similarly disposed between sensing electrode <NUM> and the subject's skin. In one embodiment, conductive gel enters the area between conductive surface <NUM> of electrode <NUM> or <NUM> and the subject's skin and forms a conduction path <NUM> from electrode <NUM> or <NUM> to the subject's skin. The conductive gel can cover conductive thread or mesh fabric <NUM> that is part of garment <NUM> and portions of which can be disposed between subject's skin and electrode <NUM> or <NUM>. In the embodiment shown in <FIG>, the therapy electrode <NUM>, <NUM> may be formed from a receptacle <NUM> and the conductive surface <NUM> may correspond to a conductive surface, for example, conductive surface <NUM> disposed on the receptacle <NUM>.

In one embodiment, after the conductive gel has been deployed to facilitate treatment, receptacles <NUM> can be replaced without replacing additional garment <NUM> components, for example, belt <NUM>. For example, belt <NUM> need not be replaced, and soiled areas of belt <NUM> can be cleaned. As a result the subject need not wait for a replacement belt <NUM>, and need not manually add conductive gel to electrodes <NUM>, <NUM> to maintain an appropriate electrical connection as a precaution in case additional treatment (e.g., shocks) become necessary while waiting for a replacement belt.

In one embodiment, permanently housing or integrating at least one of first therapy electrode <NUM> and second therapy electrode <NUM> in belt <NUM> (or elsewhere in external medical device <NUM>) ensures that they are properly inserted and configured to deliver a shock to the subject because the subject cannot, in this example, tamper with their location or configuration, or accidentally improperly insert them into belt <NUM> (e.g., backwards, not properly electrically coupled, or facing the wrong way). In one embodiment, at least one surface or a pad associated with at least one of first therapy electrode <NUM> and second therapy electrode <NUM> faces the subject's skin to make a sufficient low impedance current path between at least one of first therapy electrode <NUM> and second therapy electrode <NUM> and the subject's skin when the conductive gel is deployed. For example, first therapy electrode <NUM> or second therapy electrode <NUM> can be housed in a pocket of garment <NUM>, with a surface or side wall of garment <NUM> between the subject's skin and electrode <NUM> or electrode <NUM> having a metallic mesh pattern. The metallic mesh can include silver or other conductive metals to lower impedance between the subject's skin and the conductive surface of electrode <NUM> or electrode <NUM>.

In one embodiment, at least one of first therapy electrode <NUM> and second therapy electrode <NUM> are part of or integral to at least one of external medical device <NUM>, garment <NUM>, or belt <NUM>, with conductive gel reservoir <NUM> and a deployment mechanism configured in replaceable receptacle <NUM>.

<FIG> illustrates components of external medical device <NUM> according to one embodiment, with sensing electrodes <NUM> including at least one EKG (or ECG) electrocardiogram sensor, conductive thread <NUM> woven into belt <NUM> of garment <NUM>, and receptacle <NUM> disposed proximate to first therapy electrode <NUM> in belt <NUM>.

In one embodiment, control unit <NUM> instructs receptacle <NUM> to release the conductive gel included in conductive gel reservoir <NUM>. The released conductive gel reduces impedance between the subject's skin and first therapy electrode <NUM> and second therapy electrode <NUM>. Therapy controller <NUM> applies treatment (e.g., a shock) to the subject via first therapy electrode <NUM> and second therapy electrode <NUM>. During treatment, current follows a path between the subject's skin and first therapy electrode <NUM> and second therapy electrode <NUM> via the conductive gel. In one embodiment, after treatment, the subject removes and discards or recycles the spent receptacles <NUM>, washes any soiled areas of garment <NUM>, for example, portions of belt <NUM>, and installs replacement receptacles <NUM>. The subject or external medical device <NUM> may carry spare receptacles <NUM>. In one embodiment, the subject may wear a backup external medical device <NUM> during this changeover period.

In one embodiment external medical device <NUM> indicates to the subject whether or not receptacles <NUM> have been properly inserted. For example, audio, visual, or haptic signals, or combinations thereof, can be provided by alarm module <NUM> or monitor <NUM>. By incorporating at least one of first therapy electrode <NUM> and second therapy electrode <NUM> and associated wiring into external medical device <NUM>, garment <NUM> is more comfortable for the subject wearing it. There are fewer components to assemble and maintain, and to cause subject discomfort during use.

Receptacle <NUM> may also include a control unit <NUM> to control conductive fluid delivery and to communicate with therapy controller <NUM>, and a connection port <NUM>, for example, a winding of an induction coil (or other interface such as a connector) to interface with one or more components of the garment <NUM>, for example, alarm module <NUM> and/or monitor <NUM>.

In one embodiment, the conductive gel includes a gel, liquid, or other material that lowers impedance for energy transfer between electrodes <NUM>, <NUM>, and the subject. The conductive gel can remain on the subject's skin for a period of time, for example, several hours before it is removed, and the conductive gel remains functional as an impedance reducing material during this time period. The conductive gel in one embodiment also has sufficient shelf life to remain dormant for a period of time prior to use. In one embodiment, receptacle <NUM> indicates an expiration date of the conductive gel. Control unit <NUM> can determine the expiration date and, upon or prior to expiration, indicate via alarm module <NUM> or monitor <NUM> that receptacle <NUM> should be replaced.

In one embodiment, receptacle <NUM> can include control unit <NUM> to communicate with therapy controller <NUM> to release the conductive gel at the appropriate time. Information communicated between the receptacle <NUM> and therapy controller (via at least one control unit <NUM> located on receptacle <NUM>, therapy controller <NUM>, garment <NUM>, or combinations thereof) includes: the presence or absence of receptacle <NUM>; whether or not the conductive gel has been released from receptacle <NUM>; a fault condition that can occur if receptacle <NUM> has been commanded to release the conductive gel but the conductive gel has failed to release; the integrity of gas and/or fluid chambers associated with pressure sensor <NUM> that are configured to deliver pressure to conductive gel reservoir <NUM> to release the conductive gel; and the age of the conductive gel based, for example, on the date of manufacture of the conductive gel or of receptacle <NUM>.

In one embodiment, receptacles <NUM> are replaceable subunits of garment <NUM>. The subject can be supplied with spare receptacles <NUM> so that spent or consumed receptacles <NUM> can be quickly replaced in the event of their use during treatment, providing continuous or essentially continuous protection without having to replace belt <NUM>, electrodes <NUM> or <NUM>, or other wearable therapeutic device components. Receptacle <NUM> may also include control unit <NUM> to control conductive fluid delivery and to communicate with therapy controller <NUM>, and connection port <NUM> (for example, a winding of an induction coil or another form of connector as discussed above) to interface with garment <NUM>.

<FIG> illustrates an example of the connection between receptacle <NUM> and therapy controller <NUM> via interface <NUM>. <FIG>, as well as <FIG> and <FIG> described below, illustrate positioning sensing circuits <NUM> located external to receptacle <NUM>, for example, in a control unit <NUM> separate from the receptacle <NUM>, and on receptacle <NUM>. Some embodiments may have redundant sensing circuits <NUM> as illustrated or sensing circuits <NUM> configured to sense different parameters, while in other embodiments, only a single sensing circuit <NUM> is provided, for example, within the control unit <NUM>, if separate from the receptacle <NUM>, or in the receptacle <NUM> itself.

In one embodiment, pressure sensor <NUM> detects if gel conduit <NUM> been compromised. The gel conduit <NUM> may be purged such that its contents change color when exposed to air. In one embodiment, there can be a vacuum on the gel conduit <NUM>, and pressure sensor <NUM> detects when the gel conduit <NUM> has been compromised based on changes in its pressure. In one embodiment, therapy controller <NUM> detects when, or is informed by sensing circuit <NUM> that the conductive fluid has been released, when receptacle <NUM> has a fault condition, is missing, or improperly inserted, and when the conductive fluid is expired or approaching expiration. Therapy controller <NUM> may then indicate this status condition to the subject via its own monitor or interface, or via alarm module <NUM> or monitor <NUM>, so that the subject can take the appropriate action.

With reference to <FIG> and <FIG>, among others, a connection port <NUM> forming a connection between receptacle <NUM> and therapy controller <NUM> via garment <NUM> can incorporate an induction coil, a capacitive coupling, RF and/or IR link, other wireless connections, magnets, or can be a hardwire connection using a connector. The connection allows receptacle <NUM> to be removed and replaced, for example, after the conductive fluid has been released at the appropriate time during treatment.

Portions of gel deployment control unit <NUM> can be located entirely on receptacle <NUM>, entirely external to receptacle <NUM>, or both on receptacle <NUM> and external to receptacle <NUM> at other locations of external medical device <NUM>. For example, components of any of sensing circuit <NUM>, pressure sensor <NUM>, positioning sensor <NUM>, and activator circuit <NUM> can be part of receptacle <NUM>, external to receptacle <NUM>, or connected to receptacle <NUM> via a connection port <NUM>, for example, an induction coil.

<FIG> and <FIG> depict examples where a connection port <NUM> including an induction coil connects receptacle <NUM> with garment <NUM> and therapy controller <NUM>. In one embodiment, receptacle <NUM> electromagnetically couples with garment <NUM> via at least one induction coil. In one embodiment, a first winding of the induction coil is disposed on receptacle <NUM> and a second winding is disposed in garment <NUM>. When receptacle <NUM> is inserted into place in garment <NUM>, the first and second windings are brought into position to form an electromagnetic coupling between receptacle <NUM> and therapy controller <NUM> via garment <NUM> and its wiring. In one embodiment, the induction coil permits close proximity communication and power transfer between receptacle <NUM> and garment <NUM> (and garment <NUM>'s components) without a hardwired connection via a connector. The induction coil may be at least partially woven, sewn, or embroidered with conductive elements into garment <NUM> or components thereof such as therapy pads of electrodes <NUM>, <NUM>. In one embodiment, as illustrated in <FIG>, power for receptacle <NUM> is provided by capacitor <NUM>, with the induction coil transferring power to receptacle <NUM> from power supply <NUM> to charge capacitor <NUM>. In one embodiment, converter <NUM> converts AC power from power supply <NUM> to DC power that can be provided to any of sensing circuit <NUM>, pressure sensor <NUM>, activator circuit <NUM>, or positioning sensor <NUM>. Power for receptacle <NUM> can also be provided by battery <NUM> as illustrated in <FIG>.

In one embodiment, receptacles <NUM> are packaged as individual self contained units. For example, in a wearable therapeutic device including one first therapy electrode <NUM> and two second therapy electrodes <NUM>, three receptacles <NUM> (one for each of the three therapy electrodes) can be identical.

In one embodiment, receptacles <NUM> are packaged as individual self contained units. For example, with one first therapy electrode <NUM> and two second therapy electrodes <NUM>, three receptacles <NUM> (one for each of the three therapy electrodes) can be identical, as illustrated in <FIG>.

In one embodiment, garment <NUM> includes conductive thread <NUM> to form electrical connections between areas of garment <NUM> and between external medical device <NUM> components. First therapy electrode <NUM>, second therapy electrode <NUM>, and sensing electrode <NUM> can include conductive thread <NUM> or metallic surfaces sewn into garment <NUM>. Conductive thread <NUM> can also provide connections between any of electrodes <NUM>, <NUM>, and <NUM> and battery powered wearable therapy controller <NUM>. In one embodiment, sensing electrodes <NUM> pick up the subject's ECG (EKG) signals and provide those signals to therapy controller <NUM> and/or monitor <NUM>. Therapy electrodes <NUM>, <NUM> and the conductive fluid form part of a current path to transfer energy from therapy controller <NUM> to the subject.

In one embodiment, electrodes <NUM>, <NUM>, and/or <NUM> include conductive stitching <NUM> in various patterns to achieve proper EKG sensing and to administer therapy. In one embodiment, at least one of electrodes <NUM>, <NUM>, and <NUM> include only conductive stitching <NUM>. Garment <NUM> may include an elastic material. An example of this is illustrated in <FIG>, where connection snap <NUM> can electrically couple at least one of electrodes <NUM>, <NUM>, and <NUM> with other components of external medical device <NUM> such as garment <NUM>, receptacles <NUM> or therapy controller <NUM>. In one embodiment, at least one of electrodes <NUM>, <NUM>, and <NUM> includes conductive stitching <NUM> that holds a metal foil <NUM> or other conductive component in place in garment <NUM>. In this example, at least a portion of at least one of electrodes <NUM>, <NUM>, and <NUM> includes conductive thread <NUM> and metal foil <NUM>. An example of this is illustrated in <FIG>.

In one embodiment, conductive thread <NUM> is sewn into garment <NUM> (e.g., belt <NUM>) in a zigzag pattern that can stretch as part of garment <NUM>. This stretchable conductive thread stitching <NUM> connects therapy electrodes <NUM> and <NUM> with control unit <NUM> or other garment <NUM> components (e.g., therapy controller <NUM>, receptacle <NUM>, and sensing electrode <NUM>) in the absence of additional wires. Conductive thread (e.g., conductive wiring) <NUM> can face toward or away from the subject's skin. In one embodiment, conductive stitching <NUM> faces toward receptacle <NUM> and away from the subject's skin so as to not irritate the subject. When the conductive fluid releases, it contacts the conductive thread <NUM> and spreads through at least a portion of garment <NUM> and contacts the subject's skin. In one embodiment, an elastic tension member of garment <NUM> is positioned proximate to receptacle <NUM> to hold receptacle <NUM> in position proximate to one of electrodes <NUM> and <NUM>. When conductive stitching <NUM> faces toward the subject's skin, electrical contact between the electrodes <NUM> and/or <NUM> and the subject's skin can occur in the absence of conductive fluid.

<FIG> and <FIG> are schematic diagrams depicting an embodiment where garment <NUM> includes conductive pads <NUM> and magnets <NUM> to align garment <NUM> with receptacle <NUM> to facilitate electrical coupling between garment <NUM> and receptacle <NUM>. Conductive pads <NUM> may include conductive thread <NUM> or other textile materials woven into garment <NUM> to provide current from a current source to receptacles <NUM>. The current source can be housed within or remote from external medical device <NUM>. In one example, magnets <NUM> are disposed proximate to conductive pads <NUM>. Receptacle <NUM> can also include magnets <NUM>. Magnets <NUM> provide magnetic force (attractive or repulsive) between garment <NUM> and receptacle <NUM> to align conductive pads <NUM> with contact elements <NUM> of receptacle <NUM>. For example, attractive magnetic forces between magnets <NUM> on garment <NUM> and receptacle <NUM> can indicate alignment between conductive pads <NUM> and contact elements <NUM> of receptacle <NUM>, or repulsive magnetic forces can indicate improper alignment, facilitating the insertion of receptacle <NUM> into garment <NUM>. Receptacle <NUM> can include conductive contact elements <NUM> that align with conductive pads <NUM> when receptacle is properly positioned in garment <NUM>. Forces from magnets <NUM> align conductive contact elements <NUM> with conductive pads <NUM> to provide an electrical connection between components of garment <NUM> and receptacle <NUM>. Current may pass via this electrical connection, under control of control unit <NUM>, to release conductive fluid from receptacles <NUM>. In one embodiment, receptacle <NUM> is disposed in a pocket of garment <NUM>, and magnets <NUM> are disposed in garment <NUM> on opposite sides of receptacle <NUM> when disposed in the pocket. In one embodiment, magnets <NUM> are coated, for example in plastic, to protect from wear, damage (e.g., during washing), or high moisture conditions. In one embodiment, conductive pad <NUM> is at least part of electrode <NUM>, <NUM>, or <NUM>. In some embodiments, the magnets <NUM> and the conductive pads <NUM> on the garment may be combined into conductive magnetic elements. In some embodiments, the magnets <NUM> and conductive contact elements <NUM> on the receptacle <NUM> may be combined into conductive magnetic contact elements.

In one embodiment, garment <NUM> includes snaps to align garment <NUM> with receptacle <NUM> to facilitate electrical coupling between garment <NUM> and receptacle <NUM>. For example, snaps can fix garment <NUM> in position with contact elements <NUM> aligned with conductive pads <NUM>.

The foregoing is illustrative and not limiting, having been presented by way of example. In particular, although many of the examples presented herein involve specific combinations of or system elements, it is understood that those acts and those elements may be combined in other ways. Acts, elements and features discussed only in connection with one embodiment are not excluded from a similar role in other embodiments.

Note that in <FIG>, the enumerated items are shown as individual elements. In actual implementations of the systems and methods described herein, however, they may be inseparable components of other electronic devices such as a digital computer. Thus, actions described above may be implemented at least in part in software that may be embodied in an article of manufacture that includes a program storage medium. The program storage medium includes data signals embodied in one or more of a carrier wave, a computer disk (magnetic, or optical (e.g., CD or DVD, or both)), non-volatile memory, tape, a system memory, and a computer hard drive. The program storage medium can include at least non-transient mediums, and the signals can include at least non-transient signals.

From the foregoing, it is appreciated that the wearable therapeutic device provided herein affords a simple and effective way to automatically apply and immediately provide lifesaving care to a subject during a cardiac event without any human intervention.

Any references to embodiments or elements or acts of the systems and methods herein referred to in the singular may also embrace embodiments including a plurality of these elements, and any references in plural to any embodiment or element or act herein may also embrace embodiments including only a single element.

Any embodiment disclosed herein may be combined with any other embodiment, and references to "an embodiment," "some embodiments," "an alternate embodiment," "various embodiments," "one embodiment" or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment. Such terms as used herein are not necessarily all referring to the same embodiment. Any embodiment may be combined with any other embodiment in any manner consistent with the aspects and embodiments disclosed herein.

References to "or" should be construed as inclusive so that any terms described using "or" may indicate any of a single, more than one, and all of the described terms. Intervening embodiments, acts, or elements are not essential unless recited as such.

Where technical features in the drawings, detailed description or any aspect are followed by references signs, the reference signs have been included for the sole purpose of increasing the intelligibility of the drawings, detailed description, and aspects. Accordingly, neither the reference signs nor their absence have any limiting effect on the scope of any aspect elements.

Claim 1:
An electrode system for deploying a conductive gel in an external medical device, comprising:
a gel deployment receptacle (<NUM>) configured to release a conductive gel onto a body of a subject; and
a fluid pump (<NUM>) in fluid communication with the gel deployment receptacle;
a plurality of therapy electrodes (<NUM>, <NUM>) for delivering electric shocks disposed in a garment (<NUM>), wherein the gel deployment receptacle is associated with at least one of the plurality of therapy electrodes;
wherein the fluid pump (<NUM>) is configured to be removable after use such that the fluid pump is reusable with a different electrode system;
a control unit configured to direct the gel deployment receptacle to release the conductive gel onto the at least one of the plurality of therapy electrodes by actuation of the fluid pump that causes a working fluid to apply pressure directly or indirectly to the conductive gel such that the gel deployment receptacle releases the conductive gel prior to delivery of an electric shock.