Patent Description:
In the field of medicine, doctors often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of devices have been developed for monitoring many such physiological characteristics. Such devices provide doctors and other healthcare personnel with the information they need to provide the best possible healthcare for their patients. As a result, such monitoring devices have become an indispensable part of modern medicine.

One technique for monitoring certain physiological characteristics of a patient uses attenuation of light to determine physiological characteristics of a patient. This is used in pulse oximetry, and the devices built based upon pulse oximetry techniques. Light attenuation is also used for regional or cerebral oximetry. Oximetry may be used to measure various blood characteristics, such as the oxygen saturation of hemoglobin in blood or tissue, the volume of individual blood pulsations supplying the tissue, and/or the rate of blood pulsations corresponding to each heartbeat of a patient. The signals can lead to further physiological measurements, such as respiration rate, glucose levels or blood pressure.

One issue in such sensors relates to manufacturing of such sensors, including with regard to ease of manufacture, reliability of the manufactured sensor, repeatability of manufacture for large numbers of manufactured sensors, as well as ease, reliability, repeatability, etc. for the re-manufacture of sensors.

Traditional pulse oximeters, for example, are fairly complex with regard to the required usage of multiple parts having multiple liners, folding operations, etc., during manufacture of the sensor. Specifically, traditional assembly requires that a person manually align multiple layers together, press the layers together (attempting to correctly maintain alignment, avoid bubbles and avoid missing portions). Such sensors can be costly to assemble and may suffer from reliability/repeatability of the build. Less reliable performance may result, for example when layers are not laminated together properly, causing the layers to delaminate (open up) or when layers are not precisely aligned together, for example if the holes for optics to pass light through are not centered well enough on the optics or other materials are out of place, causing pressure points on the patient. <CIT> describes a sensor wrap including a foldable applicator which substantially and removably secures sensor elements within the sensor wrap before application of the sensor wrap to a measurement site, wherein the sensor wrap may include disposable tape layers including an information element, a breakable conductor, or both.

What is needed in the art is a construction of a sensor that eases manufacture and/or remanufacture of the sensor, while increasing reliability and repeatability of such manufacture or remanufacture.

The techniques of this disclosure generally relate to medical devices that monitor physiological parameters of a patient, such as pulse oximeters.

The invention is defined by a single piece bandage for a monitoring system according to claim <NUM>. Embodiments are defined by dependent claims <NUM>-<NUM>.

Traditional pulse oximeters, for example, are fairly complex with regard to the required usage of multiple parts having multiple liners, folding operations, etc., during manufacture of the sensor. Such sensors can be costly to assemble and may suffer from reliability/repeatability of the build.

Accordingly, the present disclosure describes a bandage that is constructed as a single piece such that plural layers of the bandage are configured together to allow for a leaflet opening of the bandage to insert a pulse oximetry circuit therein. In exemplary embodiments, the leaflet is converted by a machine to cut the proper shapes, align the shapes together and laminate all layers together. In further exemplary embodiments, at least one removable internal liner or tab is included as part of the bandage to facilitate opening of the bandage via the leaflet.

Referring now to <FIG>, an embodiment of a patient monitoring system <NUM> that includes a patient monitor <NUM> and a sensor <NUM>, such as a pulse oximetry sensor, to monitor physiological parameters of a patient is shown. By way of example, the sensor <NUM> may be a NELLCOR™, or INVOS™ sensor available from Medtronic (Boulder, CO), or another type of oximetry sensor. Although the depicted embodiments relate to sensors for use on a patient's fingertip, toe, or earlobe, it should be understood that, in certain embodiments, the features of the sensor <NUM> as provided herein may be incorporated into sensors for use on other tissue locations, such as the forehead and/or temple, the heel, stomach, chest, back, or any other appropriate measurement site.

In the embodiment of <FIG>, the sensor <NUM> is a pulse oximetry sensor that includes one or more emitters <NUM> and one or more detectors <NUM>. For pulse oximetry applications, the emitter <NUM> transmits at least two wavelengths of light (e.g., red and/or infrared (IR)) into a tissue of the patient. For other applications, the emitter <NUM> may transmit <NUM>, <NUM>, or <NUM> or more wavelengths of light into the tissue of a patient. The detector <NUM> is a photodetector selected to receive light in the range of wavelengths emitted from the emitter <NUM>, after the light has passed through the tissue. Additionally, the emitter <NUM> and the detector <NUM> may operate in various modes (e.g., reflectance or transmission). In certain embodiments, the sensor <NUM> includes sensing components in addition to, or instead of, the emitter <NUM> and the detector <NUM>. For example, in one embodiment, the sensor <NUM> may include one or more actively powered electrodes (e.g., four electrodes) to obtain an electroencephalography signal.

The sensor <NUM> also includes a sensor body <NUM> to house or carry the components of the sensor <NUM>. The body <NUM> includes a backing, or liner, provided around the emitter <NUM> and the detector <NUM>, as well as an adhesive layer (not shown) on the patient side. The sensor <NUM> may be reusable (such as a durable plastic clip sensor), disposable (such as an adhesive sensor including a bandage/liner at least partially made from hydrophobic materials), or partially reusable and partially disposable.

In the embodiment shown, the sensor <NUM> is communicatively coupled to the patient monitor <NUM>. In certain embodiments, the sensor <NUM> may include a wireless module configured to establish a wireless communication <NUM> with the patient monitor <NUM> using any suitable wireless standard. For example, the sensor <NUM> may include a transceiver that enables wireless signals to be transmitted to and received from an external device (e.g., the patient monitor <NUM>, a charging device, etc.). The transceiver may establish wireless communication <NUM> with a transceiver of the patient monitor <NUM> using any suitable protocol. For example, the transceiver may be configured to transmit signals using one or more of the ZigBee standard, <NUM>. 4x standards WirelessHART standard, Bluetooth standard, IEEE <NUM>. 11x standards, or MiWi standard. Additionally, the transceiver may transmit a raw digitized detector signal, a processed digitized detector signal, and/or a calculated physiological parameter, as well as any data that may be stored in the sensor, such as data relating to wavelengths of the emitters <NUM>, or data relating to input specification for the emitters <NUM>, as discussed below. Additionally, or alternatively, the emitters <NUM> and detectors <NUM> of the sensor <NUM> may be coupled to the patient monitor <NUM> via a cable <NUM> through a plug <NUM> (e.g., a connector having one or more conductors) coupled to a sensor port <NUM> of the monitor. In certain embodiments, the sensor <NUM> is configured to operate in both a wireless mode and a wired mode. Accordingly, in certain embodiments, the cable <NUM> is removably attached to the sensor <NUM> such that the sensor <NUM> can be detached from the cable to increase the patient's range of motion while wearing the sensor <NUM>.

The patient monitor <NUM> is configured to calculate physiological parameters of the patient relating to the physiological signal received from the sensor <NUM>. For example, the patient monitor <NUM> may include a processor configured to calculate the patient's arterial blood oxygen saturation, tissue oxygen saturation, pulse rate, respiration rate, blood pressure, blood pressure characteristic measure, autoregulation status, brain activity, and/or any other suitable physiological characteristics. Additionally, the patient monitor <NUM> may include a monitor display <NUM> configured to display information regarding the physiological parameters, information about the system (e.g., instructions for disinfecting and/or charging the sensor <NUM>), and/or alarm indications. The patient monitor <NUM> may include various input components <NUM>, such as knobs, switches, keys and keypads, buttons, etc., to provide for operation and configuration of the patient monitor <NUM>. The patient monitor <NUM> may also display information related to alarms, monitor settings, and/or signal quality via one or more indicator lights and/or one or more speakers or audible indicators. The patient monitor <NUM> may also include an upgrade slot <NUM>, in which additional modules can be inserted so that the patient monitor <NUM> can measure and display additional physiological parameters.

Because the sensor <NUM> may be configured to operate in a wireless mode and, in certain embodiments, may not receive power from the patient monitor <NUM> while operating in the wireless mode, the sensor <NUM> may include a battery to provide power to the components of the sensor <NUM> (e.g., the emitter <NUM> and the detector <NUM>). In certain embodiments, the battery may be a rechargeable battery such as, for example, a lithium ion, lithium polymer, nickel-metal hydride, or nickel-cadmium battery. However, any suitable power source may be utilized, such as, one or more capacitors and/or an energy harvesting power supply (e.g., a motion generated energy harvesting device, thermoelectric generated energy harvesting device, or similar devices).

As noted above, in an embodiment, the patient monitor <NUM> is a pulse oximetry monitor and the sensor <NUM> is a pulse oximetry sensor. The sensor <NUM> may be placed at a site on a patient with pulsatile arterial flow, typically a fingertip, toe, forehead or earlobe, or in the case of a neonate, across a foot. Additional suitable sensor locations include, without limitation, the neck to monitor carotid artery pulsatile flow, the wrist to monitor radial artery pulsatile flow, the inside of a patient's thigh to monitor femoral artery pulsatile flow, the ankle to monitor tibial artery pulsatile flow, and around or in front of the ear. The patient monitoring system <NUM> may include sensors <NUM> at multiple locations. The emitter <NUM> emits light which passes through the blood perfused tissue, and the detector <NUM> photoelectrically senses the amount of light reflected or transmitted by the tissue. The patient monitoring system <NUM> measures the intensity of light that is received at the detector <NUM> as a function of time.

A signal representing light intensity versus time or a mathematical manipulation of this signal (e.g., a scaled version thereof, a log taken thereof, a scaled version of a log taken thereof, etc.) may be referred to as the photoplethysmograph (PPG) signal. In addition, the term "PPG signal," as used herein, may also refer to an absorption signal (i.e., representing the amount of light absorbed by the tissue) or any suitable mathematical manipulation thereof. The amount of light detected or absorbed may then be used to calculate any of a number of physiological parameters, including oxygen saturation (the saturation of oxygen in pulsatile blood, SpO2), an amount of a blood constituent (e.g., oxyhemoglobin), as well as a physiological rate (e.g., pulse rate or respiration rate) and when each individual pulse or breath occurs. For SpO2, red and infrared (IR) wavelengths may be used because it has been observed that highly oxygenated blood will absorb relatively less Red light and more IR light than blood with a lower oxygen saturation. By comparing the intensities of two wavelengths at different points in the pulse cycle, it is possible to estimate the blood oxygen saturation of hemoglobin in arterial blood, such as from empirical data that may be indexed by values of a ratio, a lookup table, and/or from curve fitting and/or other interpolative techniques.

Referring now to <FIG>, an embodiment of a patient monitoring sensor <NUM> in accordance with an embodiment is shown. As may be seen, the shape or profile of various components may vary. The sensor <NUM> includes a body <NUM> that includes a flexible circuit. The sensor <NUM> includes an LED <NUM> (in this case a surface mount LED) and a detector <NUM> disposed on the body <NUM> of the sensor <NUM>.

While any number of exemplary sensor designs are contemplated herein, in the illustrated exemplary embodiment, the body <NUM> includes a flap portion <NUM> that includes an aperture <NUM>. The flap portion <NUM> is configured to be folded at a hinge portion <NUM> such that the aperture <NUM> overlaps the detector <NUM> to allow light to pass through. In one embodiment, the flap portion <NUM> includes an adhesive <NUM> that is used to secure the flap portion <NUM> to the body <NUM> after the flap portion <NUM> is folded at the hinge portion <NUM>. The exemplary flap portion <NUM> increases the surface area to reduce the contact pressure from the detector on the skin.

The sensor <NUM> includes a plug <NUM> that is configured to be connected to a patient monitoring system, such as the one shown in <FIG>. The sensor <NUM> also includes a cable <NUM> that connects the plug <NUM> to the body <NUM> of the sensor <NUM>. The cable <NUM> includes a plurality of wires <NUM> that connect various parts of the plug <NUM> to terminals <NUM> disposed on the body <NUM>. The flexible circuit is disposed in the body <NUM> and connects the terminals <NUM> to the LED <NUM> and the detector <NUM>. In addition, one of the terminals <NUM> connect a ground wire to the flexible circuit.

In exemplary embodiments, the aperture <NUM> is configured to provide electrical shielding to the detector <NUM>. In exemplary embodiments, aperture <NUM> also limits the amount of light that is received by the detector <NUM> to prevent saturation of the detector. In exemplary embodiments, the configuration of the aperture <NUM>, i.e., a number, shape, and size of the openings that define the aperture <NUM> can vary. As illustrated, in one embodiment, the aperture <NUM> includes a single round opening. In other embodiments, the aperture <NUM> can include one or more openings that have various shapes and sizes. The configuration of the aperture <NUM> is selected to provide electrical shielding for the detector <NUM> and/or control the amount of light that is received by the detector <NUM>. In exemplary embodiments, the body <NUM> includes a visual indicator <NUM> that is used to assure proper alignment of the flap portion <NUM> when folded at the hinge portion <NUM>. Further, the shape of the material of the flap portion <NUM> around the aperture <NUM> can vary, while at the same time increasing the surface area around the detector to reduce the contact pressure from the detector on the skin.

Referring now to <FIG>, a patient monitoring sensor <NUM> in accordance with an embodiment is shown. In exemplary embodiments, a faraday cage <NUM> is formed around the detector <NUM> by folding the flap portion <NUM> over a portion of the body <NUM> of the sensor <NUM>.

As we have noted, regardless of sensor configuration particulars of the above-described exemplary embodiments, a bandage is constructed as a single piece such that plural layers of the bandage are configured together to allow for a leaflet opening of the bandage to insert a pulse oximetry circuit therein. In exemplary embodiments, at least one removable internal liner or tab is included as part of the bandage to facilitate opening of the bandage via the leaflet.

<FIG> illustrates an expanded perspective view generally at <NUM> of an exemplary layered body/bandage configuration for a pulse oximeter sensor. The configuration includes: an upper bandage <NUM>; an exemplary bottom tape/patient adhesive <NUM>; exemplary top internal liner <NUM> and bottom internal liner <NUM>, which in exemplary embodiments are discarded during sensor assembly, allowing the bandage to open like a leaflet to insert the flex circuit of <FIG> into the bandage; a top light blocking layer <NUM>, a metallized tape; a bottom light blocking layer <NUM>, for example a metallized tape with holes <NUM> configured to allow light to shine through; and a disc <NUM>, comprising for example a polyethylene material, configured to reduce pressure from the LED on the patient. In exemplary embodiments, bottom tape <NUM> comprises an adhesive layer with a release liner <NUM> on the patient facing side of tape <NUM>.

<FIG> illustrates a perspective view of exemplary assembly of the flex circuit <NUM> of <FIG> into the bandage <NUM>, with internal liners <NUM>, <NUM> removed to allow positioning of the flex circuit <NUM> into the bandage, between the light blocking layers <NUM>, <NUM>. As is shown, detector <NUM> is positioned over hole <NUM>. LED <NUM> is positioned over disc <NUM> (which is positioned over another hole <NUM> (not shown in <FIG>)). Rapid assembly is facilitated by removable liners <NUM>, <NUM>, as well as the upper bandage <NUM> and light blocking layer <NUM> acting as a foldable leaflet <NUM>, the exemplary bandage construction provided as a sub-assembly configured to provide high-volume, fast and repeatable production of sensor assemblies.

Exemplary materials for backing or other material includes plastics, such as polypropylene (PP), polyester (PES), polyethylene (PE), urethanes, silicone, or the like. Additionally, various layers of the device may be constructed of one or more hydrophobic materials. Bandage, backing and additional possible layers may comprise a variety of thicknesses.

In exemplary embodiments, disc <NUM> is a thin disc (e. g, <NUM> millimeter (mm)polyethylene, which is semi-transparent and is operative to maintain the light transmission from the LED through the PET) inserted in or integral to bandage between the LED and the patient-side of the sensor, e.g., to reduce contact pressure on the skin. Other thicknesses of materials are also contemplated, for example <NUM> - <NUM>; <NUM> - <NUM>, etc. In exemplary embodiments, a PET disc <NUM> is converted with an acrylic adhesive on one side and die cut into an <NUM> millimeter (mm) disc (though ranges of sizes are contemplated, e.g., <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, etc.) that is adhered to the bottom tape of the sensor. In exemplary embodiments, the bottom tape (<NUM> in <FIG>) has an adhesive facing toward the disc <NUM>, which adheres the disc in place.

In further exemplary embodiments, the LED (<NUM> in <FIG>) is soldered to the flex circuit (<NUM> in <FIG>), which is placed on top of the adhesive side of the disc <NUM> (see <FIG>). The adhesive of the disc <NUM> secures the disc in place relative to the LED <NUM>.

Regardless, according to example embodiments described herein, the leaflet <NUM> configuration provides a bandage as a single piece such that plural layers of the bandage are configured together to allow for the leaflet opening of the bandage to insert a pulse oximetry circuit therein. In exemplary embodiments, at least one removable internal liner or tab is included as part of the bandage to facilitate opening of the bandage via the leaflet.

<FIG> illustrates a, blown-up, perspective view of another exemplary bandage generally at <NUM>. The exemplary bandage <NUM> includes an upper bandage <NUM> and an upper metalized tape <NUM> (providing shielding for sensor components, such as light sources and detectors), inserted into the bandage <NUM> when the tape <NUM> and upper bandage <NUM> are folded backwards as a leaflet. As used herein, the term "leaflet" includes any folding back of the upper bandage <NUM> such that sensor components may be installed within the bandage, followed by subsequent replacement of the upper bandage over the sensor components. According to the invention, the leaflet also contains a shielding or reinforcing component in the form of the metalized tape <NUM>, that folds back with the upper bandage <NUM>.

In further exemplary embodiments, folding back of the upper bandage <NUM> is facilitated by at least one removable internal liner <NUM> (note the two removable liners <NUM> and <NUM> in the exemplary embodiment of <FIG>). In exemplary embodiments, removal of the liner also exposes adhesive used to secure sensor components in the interior of the bandage (between upper and lower bandage components). Tabs <NUM> on upper and lower liners <NUM>, <NUM> provide two protruding surfaces that touch each other but that are not adhered to one another. Thus, a user can start an opening in the bandage using those tabs (in conjunction with similar contours above and below those removable liners) to peel the bandage open (in this case, starting on the left side where the tabs <NUM> are).

Further exemplary embodiments may use other or additional tabs or liners to facilitate folding back of the leaflet, for example the tab <NUM> in <FIG> provided on the lower bandage/tape <NUM>. Such tab <NUM> can be configured to remove from or remain in a dead space within the single piece bandage. In one exemplary embodiment, a dead zone tab <NUM> can be a thin, polyethylene film, or the like, without adhesive on either side to facilitate opening of the leaflet.

Referring again the exemplary embodiment illustrated in <FIG>, a lower metalized tape <NUM> is also positioned on the lower bandage/tape <NUM>. In exemplary embodiments, the lower bandage/tape comprises a material having a patient-side adhesive <NUM>.

<FIG> illustrates an exploded, side schematic view of the exemplary bandage <NUM> of <FIG>. Upper and lower bandage portions are generally indicated by the indicated lines <NUM>, <NUM>, respectively. Leaflet portion <NUM> folds up and back from the lower bandage portion <NUM>, in the direction of arrow <NUM> by virtue of liner <NUM>, which opens up during the maneuver. An upper surface of liner <NUM> is adhered to bandage portion <NUM>; and a lower portion is adhered to bandage portion <NUM>. In exemplary embodiments, folding of the leaflet can be also facilitated by visual or fold lines <NUM> during manufacture or remanufacture. An optional tab <NUM>, e.g., in a dead- or keep out- zone tab can further assist in opening the bandage by covering a portion of the adhesive to liner interface in a specific location (e.g., at one end of the lower bandage) to make it easier for an assembler to open the leaflet.

As we have noted, exemplary embodiments provide a single-piece bandage for a sensor, wherein an upper part of the bandage folds away from a lower bandage part to permit installation of sensor components therein. In further exemplary embodiments, the leaflet folds away along with an upper shielding or reinforcing member. In exemplary embodiments, the upper bandage portion folds away as a leaflet facilitated by at least one removable liner or tab. In exemplary embodiments, a liner <NUM> comprises a folded material configured to make it easy for the liner to be grabbed and removed during assembly. After removal of, e.g., the internal liner and placement of the electronics, the leaflet can be reclosed, completing the sensor assembly.

Thus, in exemplary embodiments, a one-piece bandage is provided with plural or all layers pre-assembled for manufacture or re-manufacture of the sensor. Exemplary embodiments also facilitate ease of manufacture or re-manufacture and produce reliable and repeatable alignment and contact of the layers, for example by eliminating need to manually align and laminate layers together.

It should be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made, which may vary from one implementation to another.

Claim 1:
A single piece bandage (<NUM>, <NUM>, <NUM>) for a patient monitoring system (<NUM>), comprising:
an upper bandage portion (<NUM>);
a lower bandage portion (<NUM>);
an adhesive (<NUM>) configured to secure at least one of a pulse oximetry light emitting diode, LED, (<NUM>) or a detector (<NUM>) at an installation position between the upper bandage portion (<NUM>) and the lower bandage portion (<NUM>); and
a releasable liner provided between the upper and lower bandage portions (<NUM>, <NUM>) to facilitate folding back of the upper bandage portion (<NUM>) relative to the lower bandage portion (<NUM>), further wherein the upper bandage portion (<NUM>) is configured to fold back down over at least one of the LED (<NUM>) or detector (<NUM>) inserted between the lower bandage portion (<NUM>) and the upper bandage portion (<NUM>),
wherein the releasable liner (<NUM>) is configured so that removal of the releasable liner exposes the adhesive,
the upper and lower bandage portions (<NUM>, <NUM>) form a leaflet configured to open by the folding back of the upper bandage portion (<NUM>) to permit installation of the pulse oximetry LED (<NUM>) or detector (<NUM>) and subsequently to close by replacement of the upper bandage portion (<NUM>) over the pulse oximetry LED or detector (<NUM>) to complete manufacture or re-manufacture of a sensor,
characterized in that
the bandage further includes a shielding member (<NUM>) at the installation position, wherein the shielding member is upper metalized tape (<NUM>) positioned on the upper bandage portion (<NUM>) and lower metalized tape (<NUM>) positioned on the lower bandage portion (<NUM>).