Patent Description:
This disclosure relates to systems and devices for sensing wetness, in particular, to systems and devices for sensing wetness during a dialysis treatment.

During dialysis treatment, arterial and venous access needles are typically inserted into a patient such that blood can be drawn from the patient through the arterial access needle, flown through a dialyzer to filter the blood, and then returned to the patient through the venous access needle. In some cases, the venous access needle may become dislodged. In the case that such an event goes unnoticed, an arterial access needle can continue to draw blood from the patient while the dislodged venous access needle does not return blood to the patient.

<CIT> describes a system of monitoring blood leaks during hemodialysis therapy includes a wetness sensing device and a hemodialysis machine. The wetness sensing device is configured to transmit information wirelessly, the information being indicative of an absence of a liquid or a presence of a liquid. The hemodialysis machine includes, or is coupled to, a wireless receiver having two or more antennas. Signals received at the two or more antennas are decoded at the wireless receiver. If decoded signals indicate a detected wetness, the hemodialysis machine is caused to halt blood flow in and out of the machine and generate an alarm.

<CIT> describes an apparatus for detecting dislodgement of a needle inserted into a patient.

<CIT> describes a needle dislodgement and blood leakage detection device.

<CIT> describes a wetness detector system that detects the presence of wetness due to a liquid leak in a system.

<CIT> describes a wetness sensor that utilizes passive resonant circuits.

In one aspect, a medical wetness sensing device includes a base adapted to be disposed on a wearer of the medical wetness sensing device. The base includes a first electrical conductor and a second electrical conductor electrically insulated from the first electrical conductor. The first electrical conductor includes a hinge portion enabling a first portion of the first electrical conductor to deflect, at the hinge portion, relative to a second portion of the first electrical conductor. The medical wetness sensing device includes a controller electrically connected to the first electrical conductor and the second electrical conductor. The controller is configured to detect a presence or an absence of a medical fluid electrically connecting the first and second electrical conductors.

In another aspect, a dialysis system is provided in accordance with appended claim <NUM>.

In an unclaimed method, an access site on skin of a patient is punctured using a needle to access a corporeal blood circuit of the patient, and a medical wetness sensing device is deformed at a hinge portion of the medical wetness sensing device to place the medical wetness sensing device on a region of the patient surrounding the access site.

Implementations can include one or more of the features described below and herein elsewhere.

In some implementations, the first electrical conductor is interlocked with the second electrical conductor.

In some implementations, the first electrical conductor includes multiple longitudinal segments interconnected by multiple lateral segments.

In some implementations, the second electrical conductor includes a hinge portion enabling a first portion of the second electrical conductor to deflect, at the hinge portion relative to a second portion of the second electrical conductor. The hinge portion of the first electrical conductor and the hinge portion of the second electrical conductor can be collinear.

In some implementations, the first and second electrical conductors include a rigid polymeric material.

In some implementations, the rigid polymeric material has an elastic modulus between <NUM> and <NUM> GPa.

In some implementations, the hinge portion comprises a living hinge.

In some implementations, the hinge portion of the first electrical conductor has a thickness at most one-half of a maximum thickness of the first electrical conductor.

In some implementations, the first electrical conductor is formed from a polymer loaded with conductive materials.

In some implementations, the medical wetness sensing device includes a first half and a second half. The first half and the second half are defined by a longitudinal axis of the medical wetness sensing device. The first portion of the first electrical conductor can extend through the first half and the second half. The second portion of the first electrical conductor can extend through only the first half.

In some implementations, the hinge portion is a first hinge portion. The first electrical conductor can further include a second hinge portion enabling the second portion of the first electrical conductor to deflect, at the second hinge portion, relative to a third portion of the first electrical conductor.

In some implementations, the first electrical conductor includes bosses. The second electrical conductor can include bosses. The medical wetness sensing device can include a housing coupled to the bosses of the first electrical conductor and the second electrical conductor to separate the first electrical conductor from the second electrical conductor.

In some implementations, the first electrical conductor includes bosses having end portions. The second electrical conductor can include bosses having end portions. The end portions of the bosses of the first electrical conductor and the end portions of the bosses of the second electrical conductor can define a surface of the base to be disposed on the wearer.

In some implementations, the base includes a cover covering at least a portion of the first electrical conductor and at least a portion of the second electrical conductor. In some cases, the medical wetness sensing device further includes a housing within which the controller is contained. The housing can engage the cover to form a fluid tight seal that inhibits entry of fluid into an interior of the housing. In some cases, the cover defines multiple portions of the first electrical conductor that are exposed on a surface of the base to be disposed on the wearer and multiple portions of the second electrical conductor that are exposed on the surface. The controller can be configured to detect the presence of the medical fluid when at least one of the multiple portions of the first electrical conductor and at least one of the multiple portions are electrically connected by the medical fluid. In some cases, the cover includes an elastomeric material.

In some implementations, the medical wetness sensing device further includes a wireless transmitter.

In some implementations, the first portion of the first electrical conductor is positioned at a central portion of the medical wetness sensing device. The second portion of the first electrical conductor can extend radially outward from the central portion. In some cases, the second electrical conductor includes a portion overlying the first portion of the first electrical conductor and positioned at the central portion of the medical wetness sensing device. The medical wetness sensing device can include an insulator positioned between the first portion of the first electrical conductor and the portion of the second electrical conductor to electrically insulate the first electrical conductor from the second electrical conductor. In some cases, the first electrical conductor includes at least three portions extending radially outward from the central portion. In some cases, the first electrical conductor includes at least four portions extending radially outward from the central portion. In some cases, the first electrical conductor includes at least four portions extending radially outward from the central portion. In some cases, the central portion contains the controller. In some cases, the second electrical conductor includes a hinge portion enabling a first portion of the second electrical conductor to deflect, at the hinge portion, relative to a second portion of the second electrical conductor. The hinge portion of the first electrical conductor can be positioned along a first arc of a circle encompassing the central portion, and the hinge portion of the second electrical conductor is positioned along a second arc of the circle.

In some implementations, the dialysis machine is a hemodialysis machine.

In some implementations, the hinge portion includes a living hinge.

In some implementations, the medical wetness sensing device includes a base adapted to be worn on skin of a wearer of the medical wetness sensing device and adapted to contact medical fluid external to the medical wetness sensing device. The base can include a first electrical conductor including a hinge portion. The hinge portion can enable a first portion of the first electrical conductor to deflect, at the hinge portion, relative to a second portion of the first electrical conductor. The base can include a second electrical conductor electrically insulated from the first electrical conductor. The medical wetness sensing device can include a controller electrically connected to the first electrical conductor and the second electrical conductor. The controller can be configured to detect a presence or an absence of the medical fluid electrically connecting the first and second electrical conductors.

In some implementations, the method further includes securing the medical wetness sensing device to the skin with cloth wrapped around an arm of the patient.

In some implementations, the method further includes initiating a hemodialysis treatment using a dialysis machine configured to receive a signal from the medical wetness sensing device. The signal can indicate an absence or presence of a medical fluid on an inner surface of the medical wetness sensing device.

Advantages of the foregoing may include, but are not limited to, one or more of those described below and herein elsewhere.

In some implementations, the flexibility of the wetness sensing device allows the wetness sensing device to conform to underlying geometries of the skin of the patient, the venous needle, and the blood lines, without applying excessive pressure that can cause discomfort for the patient. As a result, the wetness sensing device can contact any blood that leaks from the venous access site, enabling the wetness sensing device to generate signals in response to contact the blood.

The hinge portion of the electrical conductors of the wetness sensing device can reduce the number of components required to enable deflection of the base of the wetness sensing device. In some cases, the hinge portion can be an integral to the electrical conductor such that a separate hinge mechanism or separate deflection mechanism is not necessary to enable deflection of the electrical conductor. The hinge portion can be formed directly into the material forming the electrical conductors. The hinge portion can both enable deflection and enable conduction of electricity.

Because the wetness sensing device can wirelessly communicate a signal indicative of detection of contact between the wetness sensing device and a medical fluid, the wetness sensing device can be a standalone device that is not connected to external systems through wired connections. A patient wearing the wetness sensing device can thus be more easily moved around a treatment environment without disturbing electrical cables and connections between, for example, a dialysis machine and the wetness sensing device.

Access to a circulatory system of the patient may require puncturing the skin of a patient using a needle, a catheter, or other devices to form an access. Procedures that can require access to the circulatory system can include dialysis, blood filtration, hemofiltration, blood donation, blood detoxification, apheresis, cardiac catheterizations, among other blood treatment procedures. During a dialysis treatment using a dialysis machine, the needle can place the circulatory system in fluid communication with an extracorporeal system. Blood circulates through the extracorporeal system and undergoes filtering within the extracorporeal system.

In some cases, blood from the patient can leak through the access site onto the skin of the patient. The needle can, for example, dislodge from the access site during treatment due to movement of the patient or inadvertent contact with the needle, which can lead to patient blood loss.

A wetness sensing device placed over the needle and the access site can detect the blood leaking from the access site. Upon detection of a leak, the dialysis machine can alert the patient or an operator of the dialysis machine to resolve the leak, stop the treatment, or otherwise change the course of treatment in response to the leak. The wetness sensing device can be flexible and therefore conformable to the skin of the patient so that the wetness sensing device can be disposed on contours of the patient's body while maintaining close contact with the skin. Blood leakages from the access site can accordingly be quickly and reliably detected.

<FIG> illustrates a medical wetness sensing device <NUM> in use on a patient <NUM> undergoing an extracorporeal treatment (e.g., a dialysis treatment) in which blood from the patient <NUM> is circulated from the circulatory system of the patient through an extracorporeal system (e.g., a dialysis system) <NUM>. An arterial line <NUM> moves the blood from the patient <NUM> to the extracorporeal system <NUM>. The extracorporeal system <NUM> then returns the blood through a venous line <NUM> that moves the blood back to the circulatory system of the patient <NUM>.

An arterial needle <NUM> inserted into an arterial access site <NUM> of the patient <NUM> places the circulatory system of the patient <NUM> in fluid communication with the arterial line <NUM> and thus the extracorporeal system <NUM>. Similarly, a venous needle <NUM> inserted into a venous access site <NUM> places the circulatory system of the patient in fluid communication with the venous line <NUM> and thus the extracorporeal system <NUM>. The arterial needle <NUM> and the venous needle <NUM> are typically inserted into a forearm of the patient <NUM>, but other access sites can be used.

As shown in <FIG>, the wetness sensing device <NUM> is flexible, thereby allowing the wetness sensing device <NUM> to conform to the skin and to the venous needle <NUM>. In particular, an inner surface of the wetness sensing device <NUM> (e.g., a surface of the wetness sensing device <NUM> facing the venous access site <NUM>) conforms to the skin. Because of the flexibility of the wetness sensing device <NUM>, the geometry of the inner surface can closely match the geometry of the venous access site.

During use, the wetness sensing device <NUM> is disposed on the patient with gauze <NUM> positioned between the wetness sensing device <NUM> and the skin of the patient <NUM>. The wetness sensing device <NUM> is positioned over the venous needle <NUM>, and a cloth <NUM> is wrapped around the wetness sensing device <NUM> to the fix wetness sensing device <NUM> in place.

The wetness sensing device <NUM>, in response to detecting leakage of blood, can transmit wireless signals to alert external systems of the leak. The wetness sensing device <NUM> includes a wireless transceiver <NUM> (shown in <FIG>) that can communicate with a wireless transceiver <NUM> of the extracorporeal system <NUM>. The wetness sensing device <NUM> further includes a power source <NUM> to supply power to the wireless transceiver <NUM> such that the wetness sensing device <NUM> does not require a wired power connection to an external power source.

The wetness sensing device <NUM> can detect absence or presence of a liquid (e.g., blood) on the inner surface of the wetness sensing device <NUM>. Based on the detection, the operator or the extracorporeal system <NUM> can, for example, change a course of treatment to reduce risk to the patient <NUM>. The wetness sensing device <NUM> can generate an electrical signal indicating the absence or the presence of blood. The wireless transceiver <NUM> of the wetness sensing device <NUM> can receive the electrical signal and generate a wireless signal based on the electrical signal. The wireless transceiver <NUM> can transmit the wireless signals using a wireless communications technology, such as, Near Field Communication, Bluetooth, or WiFi. The wireless transceiver <NUM> can receive the wireless signal from the wireless transceiver <NUM> of the wetness sensing device. Based on the wireless signal, the wireless transceiver <NUM> can generate electrical signals that the extracorporeal system <NUM> can use to change the course of treatment.

If the wetness sensing device <NUM> does not detect blood, the wetness sensing device <NUM> can generate an electrical signal indicating the absence of blood. The extracorporeal system <NUM> receives the wireless signal indicating the absence of blood and, in response, can continue with treatment uninterrupted. In some cases, the wetness sensing device <NUM> can operate in an idle state in which it does not generate the electrical signal in the absence of blood.

In the event that a blood leak occurs due to, for example, dislodgement or disconnection of the venous needle <NUM>, the wetness sensing device <NUM> can generate a wireless signal indicating the presence of blood. In response to the wireless signal indicating the presence of blood, the extracorporeal system <NUM> can stop the treatment, reduce a pump speed of a pump of the extracorporeal system <NUM>, or otherwise change the treatment parameters to prevent additional blood leakage. Alternatively or additionally, the extracorporeal system <NUM> can display an error message or issue an alarm indicating to the operator that the blood leak has occurred. The operator can then resolve the blood leak by changing the treatment parameters or by adjusting components such as, for example, the venous needle <NUM> and the cloth <NUM>.

A flexible wetness sensing device (e.g., the wetness sensing device <NUM>) that can detect blood leaks from a patient (e.g., the patient <NUM>) can be implemented in a number of ways described herein. <FIG> depict a first example, and <FIG> depict a second example. In both of these examples, two electrical conductors are shown. For illustration purposes, exposed surfaces of a first of the electrical conductors are depicted as shaded surfaces and exposed surfaces of a second of the electrical conductors depicted as non-shaded surfaces. The examples set forth herein are merely examples and do not limit the scope of this disclosure.

Referring to <FIG>, a medical wetness sensing device <NUM> (e.g., the wetness sensing device <NUM>) includes a base <NUM> and a housing <NUM>. The base <NUM> is attached to the housing <NUM> and is adapted to be disposed on the wearer of the medical wetness sensing device <NUM>, e.g., to be secured to the wearer over gauze that has been applied to the skin of the wearer. The base <NUM> is deflectable, deformable, or both such that it can be placed around contours of the wearer's body. In some examples, the housing <NUM> does not readily deflect and is relatively more rigid than the base <NUM>.

Referring to <FIG>, the base <NUM> has an elongate shape that extends outwardly from the housing <NUM> along a longitudinal axis X1 of the wetness sensing device <NUM> in two directions. The base <NUM> has, for example, an oval shape, a rectangular shape, or other elongate shape having a longitudinal axis perpendicular to a longitudinal axis of the housing <NUM>. The longitudinal axis of the base <NUM> is aligned with the longitudinal axis X1 of the wetness sensing device <NUM>, and the longitudinal axis of the housing <NUM> is aligned with a transverse axis X2 of the wetness sensing device <NUM>. The housing <NUM> can have an oval shape, rectangular shape, or other elongate shape. In some examples, the housing <NUM> has a circular shape and is axisymmetric about a central axis X3 (shown in <FIG>). Because the longitudinal axis of the base <NUM> is transverse to the longitudinal axis of the housing <NUM>, lateral portions 205a, 205b of the base <NUM> cantilever from the housing <NUM> a greater distance, thus enabling greater deflection of the base <NUM>. Such a configuration of the housing <NUM> and the base <NUM> can enable greater unidirectional or bidirectional bending of the base <NUM> about the longitudinal axis X2 of the housing <NUM>. For example, the base <NUM> can bend upward toward the housing <NUM> and/or downward away from the housing <NUM>.

The base <NUM> includes a first electrical conductor <NUM>, a second electrical conductor <NUM>, and a cover <NUM>. <FIG> shows a bottom view of the first and second electrical conductors <NUM>, <NUM> isolated from other components of the wetness sensing device <NUM>. The first and the second electrical conductors <NUM>, <NUM> are electrically conductive but are electrically isolated from one another. For example, the first and second electrical conductors <NUM>, <NUM> can be insulated from one another. As described herein, the first and second electrical conductors <NUM>, <NUM> are formed of a rigid material and are deflectable about hinge portions.

In some examples, the first and second electrical conductors <NUM>, <NUM> are formed of a polymer loaded with conductive materials. The conductive materials increase electrical conductivity of the polymer so that electrical signals can be transmitted through the electrical conductors <NUM>, <NUM>. In some examples, the first and second electrical conductors <NUM>, <NUM> are composited with black carbon, graphene flakes, carbon nanotubes, silver, nickel, silver-coated fibers, metal fibers, metal mesh, or other conductive materials that allow the first and electrical conductors <NUM>, <NUM> to be conductive.

Both the first and second electrical conductors <NUM>, <NUM> extend along a length L1 (shown in <FIG>) of the wetness sensing device <NUM>, e.g., along an entirety of the length L1. The first and second electrical conductors <NUM>, <NUM> extend along a portion of a width W1 of the wetness sensing device <NUM>. The conductors <NUM>, <NUM> can have a maximum width between <NUM>% and <NUM>% of the width W1 of the wetness sensing device <NUM>, e.g., between <NUM>% and <NUM>%, <NUM>% and <NUM>%, <NUM>% and <NUM>%, etc., of the width W1.

Referring to <FIG> depicting a bottom view of the first electrical conductor <NUM>, the first electrical conductor <NUM> has a perimeter defined by an outer perimeter <NUM> of the wetness sensing device <NUM> (shown in <FIG>) and a series of alternating longitudinal segments <NUM> and transverse segments <NUM>. In particular, the longitudinal segments <NUM> are interconnected by the transverse segments <NUM>. The longitudinal segments <NUM> extend along axes parallel to the longitudinal axis X1 of the wetness sensing device <NUM>, and the transverse segments <NUM> extend along axes transverse to the longitudinal axis X1 of the wetness sensing device <NUM>. While ten longitudinal segments <NUM> and nine transverse segments <NUM> are shown in <FIG>, in some implementations, the first electrical conductor <NUM> includes fewer or more longitudinal segments, e.g., <NUM> or less, <NUM> or more, etc., and/or fewer or more transverse segments, e.g., <NUM> or less, <NUM> or more, etc..

Referring to <FIG> depicting a side view of the first electrical conductor <NUM>, the lateral portions 217a, 217b of the first electrical conductor <NUM> include hinge portions 218a-218f (collectively referred to as hinge portions <NUM>). The hinge portions <NUM> are electrically conductive portions of the electrical conductors <NUM>, <NUM>. In addition, the hinge portions <NUM> enable deflection of the lateral portions 217a, 217b relative to a central portion <NUM> of the first electrical conductor <NUM> as well as deflection within the lateral portions 217a, 217b. The lateral portions 217a, 217b are part of the lateral portions 205a, 205b (described with respect to <FIG>) of the wetness sensing device <NUM>, and the central portion <NUM> of the first electrical conductor <NUM> is positioned within a region beneath the housing <NUM> of the wetness sensing device <NUM>. The hinge portions 218a-218f each extend transversely along the first electrical conductor <NUM>, e.g., across an entire width of the first electrical conductor <NUM>, to enable deflection about the transverse axis X2 of the wetness sensing device <NUM>.

Hinge portions 218a, 218b connect the lateral portions 217a, 217b, respectively to the central portion <NUM>. The lateral portion 217a is deflectable, at the hinge portion 218a, relative to the central portion <NUM> of the first electrical conductor <NUM>. The lateral portion 217b is deflectable, at the hinge portion 218b, relative to the central portion <NUM> of the first electrical conductor <NUM>. For example, the lateral portions 217a, 217b are deflectable, in their entireties, about the hinge portions 218a, 218b. The lateral portions 217a, 217b are deflectable about the transverse axis X2 of the wetness sensing device <NUM>, e.g., away from the housing <NUM> or toward the housing <NUM>.

Hinge portions 218c-218f enable relative deflection of sections <NUM> of the lateral portions 217a, 217b. The sections <NUM> are connected to one another by the hinge portions 218c-218f, and adjacent sections <NUM> are deflectable relative to one another at the hinge portions 218c-218f. The sections <NUM> are deflectable at the hinge portions 218a-218f about the transverse axis X2 of the wetness sensing device <NUM>, e.g., away from the housing <NUM> or toward the housing <NUM>.

In the illustrated example, the hinge portions <NUM> include living hinges. The living hinges correspond to portions of the first electrical conductor <NUM> thinner than other portions of the first electrical conductor <NUM> surrounding the living hinges. The first electrical conductor <NUM> can be formed from a rigid material such that the thinner portions corresponding to the living hinges have reduced stiffness and thus enable deflection of the first electrical conductor <NUM>. The first electrical conductor <NUM> is monolithic such that the central portion <NUM> and the lateral portions 217a, 217b are formed from the same material. In this regard, the hinge portions <NUM> are formed from this same material. The material can be, for example, a rigid polymeric material, such as polycarbonate, polypropylene, polyethylene, etc. The elastic modulus of the material can be, for example, between <NUM> and <NUM> GPa, e.g., between <NUM> and <NUM> GPa, <NUM> and <NUM> GPa, <NUM> GPa, and <NUM> GPa, <NUM> GPa and <NUM> GPa, etc..

To enable deflection at the hinge portions <NUM>, the hinge portions <NUM> have a stiffness less than a stiffness of portions surroundings the hinge portions <NUM>, e.g., less than the sections <NUM> and the central portion <NUM>. The hinge portions <NUM>, for example, have a thickness T1 that is less than a thickness T2 of the rest of the first electrical conductor <NUM>, e.g., the sections <NUM> and the central portion <NUM>. The hinge portions <NUM> are flexible portions of the first electrical conductor that enable deflection, and the sections <NUM> and the central portion <NUM> are rigid portions that deflect, e.g., in their entireties, relative to the hinge portions <NUM>. The thickness T1 is, for example, <NUM>% to <NUM>% of the thickness T2, e.g., between <NUM>% and <NUM>%, <NUM>% and <NUM>%, <NUM>% and <NUM>%, <NUM>% and <NUM>%, at most <NUM>%, at most <NUM>%, at most <NUM>%, etc., of the thickness of T2. The relatively lower thickness T1 of the hinge portions <NUM> reduces the stiffness of the hinge portions <NUM>. In some implementations, the thickness T1 is between, for example, <NUM> to <NUM>, e.g., between <NUM> and <NUM>, <NUM> and <NUM>, <NUM> and <NUM>, <NUM> and <NUM>, etc. In some implementations, the thickness T2 corresponds to a maximum thickness of the first electrical conductor <NUM>.

As shown in <FIG>, the longitudinal axis X1 defines a first half 221a of the wetness sensing device <NUM> and a second half 221b of the wetness sensing device <NUM>. The first electrical conductor <NUM> is positioned on the first half 221a with each of the sections <NUM>, the hinge portions <NUM>, and the central portion <NUM> extending through the first half 221a. At least some of the portions of the first electrical conductor <NUM> extend through the second half 221b. As shown in <FIG>, the central portion <NUM> includes sections extending through both the first half 221a and the second half 221b. The central portion <NUM> further includes sections extending through only the first half 221a. In each of the lateral portions 217a, 217b, one or more of the sections <NUM> of the lateral portions 217a, 217b extend through both the first half 221a and the second half 221b, and one or more of the sections <NUM> extend through only the first half 221a.

Referring back to <FIG>, the first electrical conductor <NUM> is interlocked with the second electrical conductor <NUM>. The first and second electrical conductors <NUM>, <NUM> overlap one another along the longitudinal axis X1 of the wetness sensing device <NUM>. While specific configurations of the first electrical conductor <NUM> are described with respect to <FIG> and <FIG>, example configurations of the second electrical conductor <NUM> are similar. For example, the second electrical conductor <NUM> can include transverse segments and longitudinal segments to match the transverse segments <NUM> and the longitudinal segments <NUM> of the first electrical conductor <NUM>.

The second electrical conductor <NUM> includes hinge portions 222a-222f and is deflectable in a manner similar to the first electrical conductor <NUM>. In this regard, the hinge portions 222a-222f extend parallel to the transverse axis X2. The hinge portions 222a-222f can be, for example, collinear with the hinge portions 218a-218f, respectively. The hinge portions 222a-222f and the hinge portions 218a-218f are all parallel to one another. The first and second electrical conductor <NUM>, <NUM> are therefore both deflectable about the transverse axis X2, enabling the wetness sensing device <NUM> to be easily wrapped around contours when worn on the patient's body.

Rather than being positioned on the first half 221a, the second electrical conductor <NUM> is positioned on the second half 221b, with each of its sections, hinge portions, and central portion extending through the second half 221b. In addition, at least some of the portions of the second electrical conductor <NUM> extend through the first half 221a. As described herein, because at least some portions of both of the first and second electrical conductors <NUM>, <NUM> extend through both halves 221a, 221b of the wetness sensing device <NUM>, the first and second electrical conductors <NUM>, <NUM> are both more easily exposed to medical fluid present along an inner surface <NUM> of the base <NUM> (shown in <FIG>) and thus can more easily detect the medical fluid. The inner surface <NUM> includes a surface applied to or over skin of the wearer of the wetness sensing device <NUM>.

Referring to <FIG> and <FIG>, the first electrical conductor <NUM> includes bosses 224a, 224b extending in directions parallel to a central axis X3 (shown in <FIG>). The second electrical conductor <NUM> also includes bosses 226a, 226b extending in directions parallel to the central axis X3. The bosses 224a and 226a extend along axes parallel to the central axis X3 toward the housing <NUM> of the wetness sensing device <NUM> and away from the skin of the patient when the wetness sensing device <NUM> is disposed on the patient. The bosses 224b, 226b extend along axes parallel to the central axis X3 away from the housing <NUM> of the wetness sensing device <NUM> and toward the skin of the patient when the wetness sensing device <NUM> is disposed on the patient.

Referring to <FIG>, which shows the electrical conductors <NUM>, <NUM> and the housing <NUM> isolated from the cover <NUM>, the bosses 224a, 226a are directly engaged with a lower housing portion <NUM> of the housing <NUM>. The lower housing portion <NUM> includes openings <NUM> to engage with the bosses 224a of the first electrical conductor <NUM> and the bosses 226a of the second electrical conductor <NUM>. For example, the bosses 224a, 226a extend through the openings <NUM> to engage the lower housing portion <NUM>. Engagement between the bosses 224a, 226a and the lower housing portion <NUM> inhibits relative translation of the electrical conductors <NUM>, <NUM> and the housing <NUM>, e.g., along the transverse axis X2 and along the longitudinal axis X1. In addition, because the lower housing portion <NUM> is engaged with at least two bosses 224a of the first electrical conductor <NUM> and with at least two bosses 226a of the second electrical conductor <NUM>, rotation of the first and second electrical conductors <NUM>, <NUM> about the central axis X3 is inhibited.

When engaged to the bosses 224a, 226a, the lower housing portion <NUM> locks positions of the first electrical conductor <NUM> and the second electrical conductor <NUM> such that the conductors <NUM>, <NUM> are separated from one another. For example, the conductors <NUM>, <NUM> are locked in positions in which they do not directly contact one another. The cover <NUM> is positioned between the first electrical conductor <NUM> and the second electrical conductor <NUM>, thereby separating and electrically insulating the first electrical conductor <NUM> from the second electrical conductor <NUM>.

Referring to <FIG>, a separation <NUM> between the first electrical conductor <NUM> and the second electrical conductor <NUM> is defined by, for example, the engagement between the lower housing portion <NUM> and the bosses 224a, 226a. The separation <NUM> extends along the longitudinal segments and the transverse segments of the electrical conductors <NUM>, <NUM>. The separation <NUM> can have a width between, for example, <NUM> millimeters and <NUM> millimeters, e.g., between <NUM> millimeters and <NUM> millimeter, <NUM> millimeter and <NUM> millimeters, or <NUM> millimeters and <NUM> millimeters, etc. The separation <NUM> ensures electrical discontinuity between the first electrical conductor <NUM> and the second electrical conductor <NUM> such that electrical continuity between the electrical conductors <NUM>, <NUM> can serve as an indicator of a presence of a conductive medium, e.g., a medical fluid, electrically connecting the first and second electrical conductors <NUM>, <NUM>.

Referring back to <FIG>, the bosses 224b, 226b have end portions 230b, 232b defining the inner surface <NUM> of the base <NUM>. As described herein, the inner surface <NUM> is adapted to be disposed on the wearer of the wetness sensing device <NUM>. In some implementations, referring to <FIG>, the bosses 224a, 226a also have end portions 230a, 232a defining an outer surface <NUM> of the base <NUM>. The inner surface <NUM> is a surface of the wetness sensing device <NUM> that faces skin of a wearer of the wetness sensing device <NUM> and that is placed and pressed against the wearer or against gauze applied to the wearer. The inner surface <NUM> of the wetness sensing device <NUM> contacts the wearer, the gauze, or both. When the inner surface <NUM> is placed against the wearer, the base <NUM> of the wetness sensing device <NUM> deflects to conform to the skin and the venous needle, thus enabling the inner surface <NUM> to be easily in contact with medical fluid leaking from the venous needle.

The other portions of the inner surface <NUM> of the base <NUM> are defined by the cover <NUM>. The cover <NUM> can be formed from a material that is more flexible than the material forming the first and second electrical conductors <NUM>, <NUM>. The cover <NUM> can be formed from, for example, a flexible elastomeric material such as rubber, silicone, ethylene propylene diene monomer (EPDM) rubber, fluorocarbon rubber, silicone rubber, fluorosilicone rubber, polyether block amides, Chloropene rubber, Butyl rubber, among other elastomeric materials, etc. The cover <NUM> can have a low modulus of elasticity of, for example, <NUM> MPa to <NUM> MPa, e.g., <NUM> MPa to <NUM> MPa, <NUM> MPa to <NUM> MPa, or <NUM> MPa to <NUM> MPa, etc. The cover <NUM> can withstand large strains of between at least, for example, <NUM>% and <NUM>% (e.g., between at least <NUM>% to <NUM>%, <NUM>% to <NUM>%) without resulting in damage to the cover <NUM>.

The cover <NUM> extends across both top and bottom portions of the electrical conductors <NUM>, <NUM>. The first and second electrical conductors <NUM>, <NUM> are exposed along the inner surface <NUM> of the wetness sensing device <NUM>. For example, the end portions 230b, 232b of the bosses 224b, 226b extend through the cover <NUM> such that the end portions 230b, 232b are exposed on the inner surface <NUM> of the base <NUM>. The end portions 230b, 232b are exposed in this way to medical fluid that may contact the inner surface <NUM> during a treatment. In some implementations, the end portions 230a, 232a extend through the cover <NUM> such that the end portions 230a, 232a are exposed to medical fluid that may contact the outer surface <NUM> during a treatment. Blood that leaks from the wearer contacts the inner surface <NUM> and thus contacts the first and second electrical conductors <NUM>, <NUM> and the cover <NUM>. In some cases, the leaked blood is absorbed by the gauze and in turn contacts the inner surface <NUM>. Because at least some of the sections of the first electrical conductor <NUM> extend through the second half 221b and at least some of the sections of the second electrical conductor <NUM> extend through the first half 221a, the blood present on the inner surface <NUM> can be more likely to contact both the first and second electrical conductor <NUM>, <NUM>. In this regard, the presence of the blood can be more easily detected.

The housing <NUM> contains electronic components to facilitate detection of medical fluid contact with the electrical conductors <NUM>, <NUM> of the wetness sensing device <NUM>. Referring back to <FIG>, an upper housing portion <NUM> of the housing <NUM> engages the cover <NUM> to form a fluid tight seal that inhibits entry of fluid into an interior of the housing <NUM>. The upper housing portion <NUM> compresses the cover <NUM> to form the fluid tight seal.

In some examples, to manufacture the wetness sensing device <NUM>, the lower housing portion <NUM> is engaged to the first and second electrical conductors <NUM>, <NUM>, as shown in <FIG>. The cover <NUM> is then molded to the conductors <NUM>, <NUM> and to the lower housing portion <NUM> in an overmolding operation. The electrical components are then placed in the lower housing portion <NUM>. The upper housing portion <NUM> is then positioned on the lower housing portion <NUM> and locked to the lower housing portion <NUM>. The upper housing portion <NUM> is pushed against the cover <NUM> when it is positioned on the lower housing portion <NUM> to form the fluid tight seal separating the interior of the housing <NUM> from an external environment. This can prevent medical fluid from infiltrating into the interior of the housing <NUM> and damaging electrical components contained within the housing <NUM>.

As shown in <FIG>, control circuitry <NUM> is contained within the housing <NUM>. The control circuitry <NUM> can include appropriate electrical components to control operations of the control circuitry <NUM> described herein. The control circuitry <NUM> can include a microcontroller to process, generate, transmit, and receive electrical signals. The control circuitry <NUM> is electrically connected to the first electrical conductor <NUM> and the second electrical conductor <NUM>. Referring to <FIG>, the lower housing portion <NUM> includes openings <NUM> to provide access for wired electrical connections between the first electrical conductor <NUM> and the control circuitry <NUM> and wired electrical connections between the second electrical conductor <NUM> and the control circuitry <NUM>.

The control circuitry <NUM> can detect electrical continuity between the first and second electrical conductors <NUM>, <NUM> by transmitting electrical test signals through the first and second electrical conductors <NUM>, <NUM>. For example, the control circuitry <NUM> can transmit the test signals through one of the first and second electrical conductors <NUM>, <NUM> and determine whether the test signals propagate through the other electrical conductor.

The control circuit <NUM> is configured to detect a presence or an absence of a medical fluid electrically connecting the first and second electrical conductors <NUM>, <NUM>. In the absence of medical fluid, such as blood, the control circuitry <NUM> can detect that the first and second electrical conductors <NUM>, <NUM> do not form a closed electrical loop. In the presence of medical fluid, the control circuitry <NUM> can detect that the first and second electrical conductors <NUM>, <NUM> form a closed electrical loop (e.g., are electrically continuous). In particular, the medical fluid can contact both the end portions 230a, 230b of the first electrical conductor <NUM> and the end portions 232a, 232b of the second electrical conductor to form the closed electrical loop. In the presence of the medical fluid, the electrical test signal transmitted through the first and second electrical conductors <NUM>, <NUM> indicate electrical continuity between the first electrical conductor <NUM> and the second electrical conductor <NUM>.

The control circuitry <NUM> can determine that an electrical resistance below a predetermined threshold indicates that the first and second electrical conductors <NUM>, <NUM> form the closed electrical loop or are electrically continuous. Electrical resistances below a threshold between, for example, <NUM> Kohms and <NUM> Mohm can indicate electrical continuity between the first and second electrical conductors that could occur in the presence of medical fluid.

In response to detecting electrical continuity through the first and second electrical conductors <NUM>, <NUM>, the control circuitry <NUM> can generate an electrical signal indicating the presence of medical fluid along the inner surface <NUM> of the base <NUM>. Similarly, in response to detecting electrical isolation between the first and second electrical conductors <NUM>, <NUM> (e.g., the first and second electrical conductors <NUM>, <NUM> are not electrically connected), the control circuitry <NUM> can generate an electrical signal indicating the absence of medical fluid along the inner surface <NUM>. In some cases, in response to detecting the electrical isolation, the control circuitry <NUM> can simply not transmit an electrical signal. The first and second electrical conductors <NUM>, <NUM> are thus configured to cause the control circuitry <NUM> to generate a signal indicating the absence or presence of medical fluid on the inner surface <NUM>.

The control circuitry <NUM> can include a wireless transceiver, which can, based on the electrical signal, generate a wireless signal indicating the absence of medical fluid or the presence of medical fluid. The wireless signal can be transmitted to a wireless transceiver of an extracorporeal system, a dialysis machine, or other treatment device (e.g., the wireless transceiver <NUM> of <FIG>). The wireless transceiver can transmit the wireless signal until the wireless transceiver receives a wireless stop signal including instructions to stop transmitting the wireless signal. For example, the treatment device can transmit a wireless stop signal to the wireless transceiver after the medical fluid leak causing the presence of the medical fluid has been resolved.

The control circuitry <NUM> receives power from a power source <NUM> to execute various electrical operations. The control circuitry <NUM> can use the power to transmit the test signals to detect an absence or presence of electrical continuity that can be caused by the absence or presence of medical fluid on the inner surface <NUM> of the base <NUM>. In some implementations, the power source <NUM> is removably housed in the housing <NUM>. The upper housing portion <NUM> is removable from the lower housing portion <NUM> so that the power source <NUM> can be removed and inserted. As a result, the power source <NUM> can be replaceable in an event that the power source <NUM> does not have sufficient power to energize the control circuitry <NUM>.

While in the absence of medical fluid, the wetness sensing device <NUM> can operate in an idle state in which the control circuitry <NUM> transmits the electrical test signals without generating the electrical signal and the wireless signal. The idle state has a reduced power requirement, as the control circuitry <NUM> does not operate the wireless transceiver during the idle state.

<FIG> describe a wetness sensing device <NUM> in accordance with additional implementations. Referring to <FIG>, the wetness sensing device <NUM> differs from the wetness sensing device <NUM> in that the wetness sensing device <NUM> has a base <NUM> that extends radially outward from a housing <NUM> of the wetness sensing device <NUM>. The base <NUM> extends in directions along both a longitudinal axis Y1 and a transverse axis Y2 of the wetness sensing device <NUM>. Because the base <NUM> extends in both directions, the base <NUM> is deflectable about both the longitudinal axis Y1 and the transverse axis Y2, thus providing greater degrees of freedom of bending what is provided by the base <NUM> of the wetness sensing device <NUM>. Whereas the longitudinal axis X1 of the wetness sensing device <NUM> is typically aligned with curvature of the patient's body so that the base <NUM> can be wrapped around the patient's body, the base <NUM> can be placed on the patient's body in any orientation of the longitudinal axis Y1 and the transverse axis Y2. The base <NUM> can have, for example, a shape that is axisymmetric about a central axis Y3 of the wetness sensing device <NUM>. The base <NUM> can be, for example, circular, with a center of the circle defining the base <NUM> coinciding with the central axis Y3 of the wetness sensing device <NUM>.

Referring to <FIG>, similar to the wetness sensing device <NUM>, the wetness sensing device <NUM> includes a first electrical conductor <NUM> and a second electrical conductor <NUM>. Referring to <FIG> and <FIG>, the first electrical conductor <NUM> includes a central portion <NUM> and radially extending portions 317a-317d (collectively referred to as radially extending portions <NUM>). The central portion <NUM> is, for example, cross-shaped and has a lobe 323a-323d attached to each of the radially extending portions 317a-317d.

Each of the radially extending portions 317a-317d extends radially outward from the central portion <NUM>. The radially extending portions 317a-317d can be, for example, sectors of a circle defining an outer perimeter <NUM> (shown in <FIG>) of the wetness sensing device <NUM>. A subtended angle of each sector can be, for example, between <NUM> and <NUM> degrees, e.g., between <NUM> and <NUM> degrees, between <NUM> degrees and <NUM> degrees, between <NUM> degrees and <NUM> degrees, etc..

While the following description is presented in reference to the radially extending portion 317a, the radially extending portions 317b-317d include features that are similar to or identical to the features of the radially extending portion 317a. In some examples, the first electrical conductor <NUM> is axisymmetric about the central axis Y3 such that the radially extending portions 317a-317d are identical to one another.

Hinge portions 318a-318c (collectively referred to as hinge portions <NUM>) of the radially extending portion 317a enable deflection of the radially extending portions 317a relative to the central portion <NUM> of the first electrical conductor <NUM> as well as deflection within the radially extending portion 317a. The hinge portion 318a connects the radially extending portion 317a to the central portion and enables the radially extending portion 317a to deflect, e.g., in its entirety, relative to the central portion <NUM>. The hinge portions 318b, 318c enable relative deflection of sections <NUM> of the radially extending portion 317a relative to adjacent sections <NUM>.

Rather than extending linearly as the hinge portions <NUM> of the wetness sensing device <NUM> do, the hinge portions <NUM> extend along circles 351a-351c (shown in <FIG>) that circumscribe the central portion <NUM>, e.g., having centers aligned with the central axis Y3. The circle 351a, for example, can define the extent of the central portion <NUM> of the first electrical conductor <NUM> and the extent of a central portion <NUM> of the second electrical conductor <NUM>. The hinge portions <NUM> extend along different arcs of these circles 351a-351c. The arcs for the hinge portions <NUM> have, in some cases, angles of curvature identical to the subtend angle of the sector defined by the radially extending portion 317a. In this regard, the hinge portions <NUM> further from the central axis Y3 have greater lengths than the hinge portions <NUM> close to the central axis Y3.

Similar to the hinge portions <NUM> described with respect to the wetness sensing device <NUM>, as shown in <FIG>, the hinge portions <NUM> can include, for example, living hinges. The first electrical conductor <NUM> can be formed from a monolithic material that forms the central portion <NUM> and the radially extending portions 317a-317d. The material is similar to the material described for the hinge portions <NUM> of the wetness sensing device <NUM>. The relative thicknesses of the hinge portions <NUM> and the sections <NUM> are similar to the relative thicknesses of the hinge portions <NUM> and the sections <NUM>.

Similar to the bosses 224a, 224b of the first electrical conductor, referring to <FIG>, <FIG>, and 10C, bosses 324a, 324b of the first electrical conductor <NUM> extend in directions parallel to the central axis Y3. The bosses 324a, 324b are only positioned within the radially extending portions 317a-317d and not the central portion <NUM>. However, in some implementations, the central portion <NUM> includes bosses extending along the central axis Y3. Because the size of the sections <NUM> further from the central axis Y3 are larger than the size of the sections <NUM> close to the central axis Y3, the sections <NUM> further from the central axis Y3 have a greater number of bosses 324a, 324b than the sections <NUM> closer to the central axis Y3.

The second electrical conductor <NUM> is similar to the first electrical conductor <NUM> except that the central portion <NUM> of the second electrical conductor <NUM> includes bosses 326b within the central portion <NUM>. The second electrical conductor <NUM> also includes other features, as described herein, that enables engagement between the first and second electrical conductors <NUM>, <NUM>. As shown in <FIG>, hinge portions 322a-322c (collectively referred to as hinge portions <NUM>) of the second electrical conductor <NUM> are positioned along the circles 351a-351c but along different arcs along the circles 351a-351c.

Rather than being interlocked with one another in the manner described with respect to the first and second electrical conductors <NUM>, <NUM>, as shown in <FIG>, the first and second electrical conductors <NUM>, <NUM> are both positioned at a central portion of the medical wetness sensing device <NUM>, e.g., proximate the central axis X3 of the wetness sensing device <NUM>. The central portion <NUM> of the second electrical conductor <NUM> overlies the central portion <NUM> of the first electrical conductor <NUM>.

Referring to <FIG>, an insulator <NUM> is positioned between the central portion <NUM> of the second electrical conductor <NUM> and the central portion <NUM> of the first electrical conductor <NUM> (shown in <FIG>). The insulator <NUM> is a spacer that electrically isolates the electrical conductors <NUM>, <NUM> from one another and inhibits electrical contact between the central portions <NUM>, <NUM> of the electrical conductors <NUM>, <NUM>.

Referring back to <FIG>, the bosses 324b, 326b have end portions 330b, 332b defining an inner surface <NUM> of the base <NUM>. Similar to the inner surface <NUM>, the inner surface <NUM> is adapted to be disposed on the wearer of the wetness sensing device <NUM>. As shown in <FIG>, the bosses 324a, 324b, 326a, 326b are similar to the bosses 224a, 224b, 226a, 226b in that they have exposed end portions 330b, 332b on the inner surface <NUM> of the base <NUM> and outer surface <NUM> of the base <NUM>. The inner surface <NUM> is placed and pressed against the wearer or against gauze over skin of the wearer, the base <NUM> of the wetness sensing device <NUM> deflects to conform to the skin and the venous needle and, despite uneven and sharp geometries that the combination of the wearer's skin and the venous needle generate, to remain secured to the wearer.

The other portions of the inner surface <NUM> and the outer surface <NUM> of the base <NUM> are defined by the cover <NUM>, e.g., formed in a manner similar to the cover <NUM>. The cover <NUM> extends across both top and bottom portions of the electrical conductors <NUM>, <NUM>. The first and second electrical conductors <NUM>, <NUM> are exposed along the inner surface <NUM> of the wetness sensing device <NUM>. In particular, the end portions of the bosses 324b, 326b extend through the cover <NUM> such that the bosses 324b, 326b are exposed on the inner surface <NUM> of the base <NUM> and thus may contact medical fluid during a treatment. In addition, the cross-shaped central portion <NUM> of the first electrical conductor <NUM> is exposed along the inner surface <NUM>, while the bosses 326b of the central portion <NUM> of the second electrical conductor <NUM> are exposed along the inner surface <NUM>.

The housing <NUM> is similar to the housing <NUM> and thus contains electronic components to facilitate detection of medical fluid contact with the electrical conductors <NUM>, <NUM> of the wetness sensing device <NUM>. The housing <NUM> thus contains control circuitry and engages the cover <NUM> to form the fluid tight seal to inhibit fluid from leaking into the housing <NUM>.

In some implementations, as shown in <FIG>, a lower housing portion <NUM> of the housing <NUM> is directly fastened to the first electrical conductor <NUM>. Fasteners <NUM> are positioned to secure the lower housing portion <NUM> to the first electrical conductor <NUM>. Other fasteners may be present to secure the lower housing portion <NUM> to the second electrical conductor <NUM>. The fasteners <NUM> and the other fasteners can inhibit relative rotation and translation of between the first and second electrical conductors <NUM> and the housing <NUM>. The second electrical conductor <NUM> is positioned between the first electrical conductor <NUM> and the lower housing portion <NUM>. The lower housing portion <NUM> includes an alignment boss <NUM> that extends through a corresponding opening in the second electrical conduct <NUM> and engages with a corresponding bore (not shown) on the first electrical conductor <NUM>. The alignment boss <NUM>, when engaged with the first and second electrical conductors <NUM>, <NUM>, aligns the electrical conductors <NUM>, <NUM> with the central axis Y3 of the wetness sensing device <NUM>.

While the electrical conductors <NUM>, <NUM> are described and shown as including four radially extending portions are shown, in some implementations, an electrical conductor includes fewer or more radially extending portions, e.g., at least three radially extending portions, at least four radially extending portions, etc..

The wetness sensing devices described herein (e.g., the wetness sensing device <NUM>, the wetness sensing device <NUM>) can be used with dialysis systems. As shown in <FIG>, for example, a dialysis system <NUM> includes a dialysis machine <NUM> connected to the patient <NUM>.

The arterial needle <NUM> inserted into the arterial access site <NUM> on the patient <NUM> connects the circulatory system of the patient <NUM> to the dialysis machine <NUM> to allow blood from the patient <NUM> to flow through an arterial line <NUM> to a dialyzer <NUM> of the dialysis machine <NUM>. Dialysis solution (e.g., dialysate, salt solution) flows alongside the blood flowing through the dialyzer <NUM> to filter the blood. The venous needle <NUM> inserted into the venous access site <NUM> connects the dialyzer <NUM> to the circulatory system of the patient <NUM> to allow filtered blood to flow from the dialyzer <NUM> through a venous line set <NUM>. The venous line set <NUM> includes a venous line <NUM> to conduct the filtered blood toward the patient and a drip chamber <NUM> to remove, for example, air, debris, clots, and other particulate matter from the filtered blood. A peristaltic pump <NUM> compresses portions of the arterial line <NUM> to generate a flow of the filtered blood through the arterial line <NUM> and the venous line set <NUM> so that blood can be circulated throughout the dialysis system <NUM>.

The wetness sensing device <NUM> (which can be any of the wetness sensing devices described herein, e.g., the wetness sensing device <NUM> or the wetness sensing device <NUM>) applied on the patient <NUM> in the vicinity of the venous access site <NUM> on top of the venous needle <NUM> detects blood leaks from the venous access site <NUM>. In an absence of liquid (e.g., blood) contacting an inner surface of the wetness sensing device <NUM>, the wetness sensing device <NUM> can operate in an idle state. In the idle state, a power source (e.g., the power source <NUM>, the power source <NUM>) can supply power to a circuit (e.g., the control circuitry <NUM>) of the wetness sensing device <NUM> to generate electrical test signals that can detect a presence of blood. The electrical test signals may not indicate the presence of blood, and the wetness sensing device <NUM> can continue to periodically generate the electrical test signals to detect absence/presence of the blood.

When the electrical test signals indicate the presence of blood, the wetness sensing device <NUM> can communicate with the dialysis machine <NUM> to indicate to the dialysis machine <NUM> that a blood leak has occurred. The wetness sensing device <NUM> can include a wireless transceiver (e.g., the wireless transceiver of the control circuitry <NUM>) that can transmit a wireless signal that a wireless transceiver <NUM> of the dialysis machine <NUM> can receive. The wireless signal can indicate that the wetness sensing device <NUM> has detected a presence of blood due to, e.g., blood leaking around the venous access site <NUM> from the venous needle <NUM>. The wireless transceiver <NUM> can generate electrical signals in response to receiving the wireless signal.

A controller <NUM> of the dialysis machine <NUM> can receive and transmit electrical signals operable to and from systems of the dialysis machine <NUM>. For example, the controller <NUM> can receive electrical signals from the wireless transceiver <NUM>. The electrical signals can indicate that the wetness sensing device <NUM> has detected the presence of blood. Based on the electrical signals, the controller <NUM> can modify operations of components of the dialysis machine <NUM>, such as a pump speed of the peristaltic pump <NUM>, a display <NUM> of the dialysis machine <NUM>, and other electrical and electromechanical systems.

A method of using a wetness sensing device (e.g., the wetness sensing device <NUM>, the wetness sensing device <NUM>, or other wetness sensing device described herein) during a dialysis treatment of a patient is described herein.

An operator (e.g., a patient, a physician, a nurse, a medical practitioner) punctures an access site on skin of the patient to access a corporeal blood circuit of the patient. Before initiating the dialysis treatment, now also referring to <FIG>, <FIG>, and <FIG>, the operator can disinfect and clean skin of the patient <NUM> and then insert the arterial needle <NUM> into the arterial access site <NUM> and the venous needle <NUM> into the venous access site <NUM>. The operator can thus use the arterial needle <NUM> and the venous needle <NUM> to puncture the respective access sites <NUM>, <NUM> on the skin of the patient to access the circulatory system of the patient <NUM>. The arterial needle <NUM> and the venous needle <NUM>, when inserted, place the circulatory system of the patient <NUM> in fluid communication with the dialysis machine <NUM>.

As shown in <FIG> and <FIG>, after inserting the arterial needle <NUM> and the venous needle <NUM>, the operator places the wetness sensing device <NUM> over the skin of the patient <NUM> in the vicinity of the venous access site <NUM>. In some cases, the gauze <NUM>, as shown in <FIG>, is placed over the needle, and then the wetness sensing device <NUM> is placed over the gauze <NUM>. The operator can, for example, firmly place the inner surface of the wetness sensing device <NUM> against the gauze <NUM> and against the venous access site <NUM> such that the inner surface of the wetness sensing device <NUM> conforms to the venous access site <NUM>. In the event of a blood leak from the patient <NUM>, the gauze <NUM> absorbs the blood, the wetness sensing device <NUM> detects the blood through the gauze <NUM>. The flexibility of the wetness sensing device <NUM> allows the inner surface of the wetness sensing device <NUM> to conform to the gauze <NUM>, which in turn conforms to the skin. The inner surface of the wetness sensing device <NUM> is able to maintain contact with the gauze <NUM> and thus easily detect any blood that leaks onto the gauze <NUM>. The wetness sensing device <NUM> can detect blood that leaks from the venous access site <NUM> in the event of, for example, dislodgement of the venous needle <NUM>.

As shown in <FIG> in which the wetness sensing device <NUM> corresponds to the wetness sensing device <NUM>, the wetness sensing device <NUM> is disposed on the patient <NUM> such that the base <NUM> of the wetness sensing device <NUM> bends along the contours of the patient <NUM>. Similarly, as shown in <FIG> in which the wetness sensing device <NUM> corresponds to the wetness sensing device <NUM>, the wetness sensing device <NUM> is disposed on the patient such that the base <NUM> of the wetness sensing device <NUM> bends along the contours of the patient <NUM>. The hinge portions of the wetness sensing devices <NUM>, <NUM> described herein enable the bending of the bases.

Referring back to <FIG>, <FIG>, and <FIG>, to secure the wetness sensing device <NUM> to the skin surrounding the venous access site <NUM>, the operator can apply the cloth <NUM> around the gauze <NUM> and the wetness sensing device <NUM> to secure the wetness sensing device <NUM> against the skin or the gauze <NUM>. The operator can wrap the cloth <NUM> around an arm of the patient <NUM> such that the inner surface of the wetness sensing device <NUM> is pressed against the venous access site <NUM>, the skin of the patient <NUM>, and the venous needle <NUM>. The wetness sensing device <NUM> can seal the inner surface of the wetness sensing device <NUM> from an outside environment such that blood leaking from the venous access site <NUM> remains sealed between the inner surface and the skin of the patient <NUM>. As described herein, during use of the wetness sensing device <NUM>, the flexibility of the wetness sensing device <NUM> can enable the wetness sensing device <NUM> to conform to the skin and the venous needle <NUM>, thus improving the reliability of the wetness sensing device <NUM> to detect blood leaks.

The operator can initiate the dialysis treatment on the dialysis machine <NUM>. Before initiating the dialysis treatment, the operator can further set various dialysis treatment parameters of the dialysis machine <NUM>. When the operator initiates the dialysis treatment, the peristaltic pump <NUM> of the dialysis machine <NUM> circulates the blood from the patient <NUM> through the dialyzer <NUM> to clean and filter the blood. Blood can travel along the venous line set <NUM> from the patient <NUM> through the arterial needle <NUM> to the dialyzer <NUM>. After the dialyzer <NUM> filters the blood, filtered blood can exit the dialyzer <NUM> and travels along the venous line set <NUM> through the venous needle <NUM> back to the patient <NUM>. Within the dialyzer <NUM>, alongside the flowing blood, a dialysis solution that can include salts, buffers, and/or acids can remove toxins from the blood.

During treatment, if a blood leak occurs around the venous access site <NUM>, the blood can cause the wetness sensing device <NUM> to generate a wireless signal in response to the presence of the blood, as described herein. The blood can contact an inner surface of the wetness sensing device <NUM> and then generate an electrically conductive path that would otherwise not be present in the absence of the blood. The wireless transceiver <NUM> of the dialysis machine <NUM> can receive the wireless signal and transmit a corresponding electrical signal to the controller <NUM> of the dialysis machine <NUM>. In response to the electrical signal, the controller <NUM> can control various operations of the dialysis machine <NUM>. For example, the controller <NUM> can adjust the pump speed of the peristaltic pump <NUM>, turn off the peristaltic pump <NUM>, activate an audible alarm through a speaker, and/or display an error message on the display <NUM> of the dialysis machine.

In response to changes in operation of the dialysis machine <NUM> (e.g., by triggering the alarm, by issuing an error message, or altering an operation of the peristaltic pump <NUM>), the operator can modify the course of treatment to resolve the blood leak. The operator can replace a component of the dialysis machine <NUM>, such as, for example, the venous needle <NUM>, the wetness sensing device <NUM>, or the venous line set <NUM>. In some cases, dislodgement of the venous needle <NUM> may have caused the blood leak, and the operator can simply adjust how the venous needle <NUM> is inserted into the patient <NUM> (e.g., a depth of penetration of the venous needle <NUM>, an angle of penetration of the venous needle <NUM>).

In the absence of blood, the control circuitry <NUM> may operate the wetness sensing device <NUM> in an idle state in which the controller monitors the wetness sensing device <NUM> to determine if the wetness sensing device <NUM> is detecting a presence/absence of blood. For example, the controller can periodically transmit electrical test signals that determine whether a closed electrical loop has been formed between different electrical conductors of the wetness sensing device <NUM>, as described herein.

After completion of the dialysis treatment, the operator can remove and dispose of the wetness sensing device <NUM>. The operator can then disconnect the arterial needle <NUM> and the venous needle <NUM> from the patient <NUM> and dispose of the venous line set <NUM>.

The examples described herein can be implemented in a variety of ways without departing from the scope of the specification.

The examples of using wetness sensing devices described with respect to <FIG> and <FIG> are directed to a dialysis treatment, though, in other implementations, the wetness sensing devices can be used for other appropriate medical treatments. As described herein, the wetness sensing devices can be used for medical procedures requiring access to the circulatory of the patient, such as cardiopulmonary bypass procedures, apheresis procedures, etc..

While the hinge portions <NUM>, <NUM>, <NUM>, <NUM> are described as being integral to the electrical conductors, in some implementations, the hinge portions <NUM>, <NUM>, <NUM>, <NUM> each include a movable joint mechanism connecting adjacent sections of the electrical conductors. In some implementations, the movable joint mechanism includes a living hinge as described herein or rigid hinges enabling relative rotation of the adjacent sections of the electrical conductors. For example, rather than deforming to enable relative rotation of adjacent sections, the hinge portions <NUM>, <NUM> include a bearing about which adjacent sections pivot.

The wetness sensing devices can additionally be used to detect liquids other than blood. These liquids can be removed or introduced to a patient. For example, the wetness sensing devices can be used to detect peritoneal dialysis fluid during a peritoneal dialysis treatment. The wetness sensing devices alternatively can be used to detect hemodialysis fluid during a hemodialysis treatment. In another example, the wetness sensing devices can be used during a diabetes treatment and can detect presence of insulin. The wetness sensing devices can be used during intravenous fluid delivery to detect water, saline, or other solutions. The wetness sensing devices can be use during drug delivery and other appropriate treatments in which liquid is transferred to and from the patient.

The wetness sensing devices (e.g., the wetness sensing device <NUM>) have been described to be placed above the venous access site (e.g., the venous access site <NUM>). Additionally or alternatively, the wetness sensing devices can be placed on top an arterial access site to detect blood leaking as the blood travels away from the patient.

The control circuitry <NUM> determines whether continuity exists between separated electrical conductors <NUM>, <NUM>, <NUM>, <NUM> to detect presence of liquid on the inner surface of the wetness sensing device <NUM>, <NUM>. Electricity continuity has been described to be indicated by a resistance below a threshold resistance for the electrical path that the electrical test signal takes along the electrical conductors <NUM>, <NUM>, <NUM>, <NUM>. The threshold resistance can vary depending on the conductivities of the cover or other insulative portions of the wetness sensing device. In addition, the threshold resistance can vary depending on the conductivities of the electrical conductors of various implementations of wetness sensing devices described herein.

In some examples, electrical systems of a wetness sensing device may detect changes in appropriate characteristics that can change in presence of liquid such as blood. The electrical systems may interpret a change in capacitance, current, voltage, or other appropriate electrical parameter as indicative of presence of liquid.

Patterns of exposed portions of the electrical conductors <NUM>, <NUM>, <NUM>, <NUM> along the inner surfaces of the wetness sensing devices <NUM>, <NUM> can be modified. The appropriate pattern to utilize may be determined based upon manufacturing characteristics such as cost and feasibility. In some cases, the wetness sensing devices include partitions that include separated sections that each independently detect liquid. The overall conductive pattern may comprise multiple sections each including electrical conductors. The sections, in the presence and absence of blood alike, do not include an electrically continuous path between the sections. The sections and patterns may be arranged in any manner known in the art. For example, the inner surfaces of wetness sensing devices can be divided into quadrants, which can allow the wetness sensing devices to further determine a location, among four quadrants of the inner surface, where blood is detected.

The wetness sensing devices and the dialysis machine include wireless transceivers. In some cases, the wetness sensing devices can include wireless transmitters and the dialysis machine can include a wireless receiver. When the wetness sensing devices transmit wireless signals over the wireless transmitters, the microcontroller of the wetness sensing devices can disable transmission of the wireless signals after a predetermined period of time, such as, for example, <NUM> to <NUM> minutes.

Software implementations of aspects of the system described herein may include executable code that is stored in a computer-readable medium and executed by one or more processors. The computer-readable medium may include volatile memory and/or non-volatile memory, and may include, for example, a computer hard drive, ROM, RAM, flash memory, portable computer storage media such as a CD-ROM, a DVD-ROM, a flash drive and/or other drive with, for example, a universal serial bus (USB) interface, and/or any other appropriate tangible or non-transitory computer-readable medium or computer memory on which executable code may be stored and executed by a processor. The system described herein may be used in connection with any appropriate operating system.

Claim 1:
A medical wetness sensing device (<NUM>, <NUM>), comprising:
a base (<NUM>, <NUM>) adapted to be disposed on a wearer of the medical wetness sensing device, wherein the base comprises
a first electrical conductor (<NUM>, <NUM>, <NUM>, <NUM>) comprising a hinge portion (<NUM>, <NUM>) enabling a first portion of the first electrical conductor to deflect, at the hinge portion, relative to a second portion of the first electrical conductor, and
a second electrical conductor (<NUM>, <NUM>, <NUM>, <NUM>) electrically insulated from the first electrical conductor; and
a controller (<NUM>) electrically connected to the first electrical conductor and the second electrical conductor, the controller configured to detect a presence or an absence of a medical fluid electrically connecting the first and second electrical conductors.