Integrated cross-contamination sensor

Abstract

In some embodiments, a medical system comprises: a dialysis machine having at least one exterior surface to be disinfected at a given location; at least one disinfection sensor connected to the dialysis machine at the given location, the disinfection sensor comprising two or more electrodes in fluid contact with the exterior surface of the dialysis machine and a conductivity sensor component in electrical contact with the two or more electrodes, the conductivity sensor component being configured to transmit an electrical signal indicative of the conductivity of a liquid located on the exterior surface of the dialysis machine and in contact with the two or more electrodes; a processor configured to receive the electrical signal and thereby determine a disinfection status of the given location; and a user interface configured to indicate the disinfection status of the given location.

Description

Technical Field

[0001] The present invention relates to the detection of contamination. Background Art

[0002] Renal insufficiency or failure, particularly in end-stage renal disease, results in the body's inability to remove water and minerals, excrete harmful metabolites, maintain acid-base balance, and control electrolyte and mineral concentrations within the physiological range. Toxic uremic waste metabolites, including urea, creatinine, and uric acid, accumulate in body tissues and can lead to death if the kidneys' filtering function is not replaced.

[0003] Dialysis is commonly used to replace kidney function by removing these waste toxins and excess water. In one type of dialysis treatment (hemodialysis), toxins are filtered out of the patient's blood externally in a hemodialysis machine. Blood from the patient passes through a dialyzer, where it is separated from a large amount of externally supplied dialysis solution by a semipermeable membrane. Waste products and toxins are dialyzed from the blood through the semipermeable membrane into the dialysis solution, which is then discarded. Summary of the Invention

[0004] The present disclosure generally relates to dialysis systems and methods. The dialysis system includes an integrated system that can determine whether durable medical devices have been properly disinfected. Known infection control methods include properly disinfecting medical devices, particularly frequently touched surfaces, training and closely supervising all staff on infection control best practices, and conducting internal inspections to ensure adherence to best practices. Proper disinfection protocols are important for patient outcomes, as approximately 10% of patients with end-stage renal disease died from infections in 2012.

[0005] In some embodiments, a medical system comprises: a dialysis machine having at least one exterior surface to be disinfected at a given location; at least one disinfection sensor connected to the dialysis machine at the given location, the disinfection sensor comprising two or more electrodes in fluid contact with the exterior surface of the dialysis machine and a conductivity sensor component in electrical contact with the two or more electrodes, the conductivity sensor component configured to transmit an electrical signal indicative of the conductivity of a liquid located on the exterior surface of the dialysis machine and in contact with the two or more electrodes; a processor configured to receive the electrical signal and thereby determine a disinfection status of the given location; and a user interface configured to indicate the disinfection status of the given location.

[0006] Embodiments may include one or more of the following features. Determining the disinfection status of a given location includes determining whether the conductivity signal indicates that the liquid on the outer surface of the dialysis machine is a disinfecting fluid. Determining whether the conductivity signal indicates that the liquid on the outer surface of the dialysis machine is a disinfecting fluid includes comparing the conductivity signal with a conductivity signal stored in a memory connected to the processor. Determining the disinfection status of the given location includes determining a time interval during which the disinfecting fluid is present on the outer surface of the dialysis machine. Determining the disinfection status of the given location includes comparing the time interval to a threshold time interval. Determining the disinfection status of the given location includes identifying the disinfecting fluid present on the outer surface of the dialysis machine. The user interface is configured to alert a user that the dialysis machine needs cleaning. A memory for storing a disinfection log is also included. A cleanable channel located on the outer surface of the dialysis machine is also included for collecting a known amount of liquid.

[0007] In some embodiments, a method comprises: receiving, at a processor, a signal from a conductivity sensor indicating conductivity of a liquid on an external surface of a dialysis machine at a given location and in fluid contact with an electrode of the conductivity sensor; determining a disinfection status of the external surface at the given location; and displaying the disinfection status of the external surface at the given location on a user interface.

[0008] Embodiments may include one or more of the following features. Determining the disinfection status of a given location includes determining whether the conductivity signal indicates that the liquid on the outer surface of the dialysis machine is a disinfecting fluid. Determining whether the conductivity signal indicates that the liquid on the outer surface of the dialysis machine is a disinfecting fluid includes comparing the conductivity signal with a conductivity signal stored in a memory connected to the processor. Determining the disinfection status of the given location includes determining a time interval during which the disinfecting fluid is present on the outer surface of the dialysis machine. Determining the disinfection status of the given location includes comparing the time interval to a threshold time interval. Determining the disinfection status of the given location includes identifying the disinfecting fluid present on the outer surface of the dialysis machine. Alerting a user that the dialysis machine requires cleaning. Storing a disinfection log in the memory.

[0009] Dwell time refers to the amount of time a disinfectant must remain wet on a surface to meet the specific kill requirements for a particular pathogen.

[0010] Advantages of the systems and devices described herein include the use of relatively low-cost, ubiquitous sensors (eg, disinfection sensors, which may include moisture / humidity sensors, conductivity sensors, chemical sensors, etc.) to ensure proper hygiene.

[0011] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of a dialysis system including a dialysis machine.

[0013] Figure 2A -D shows the locations of surfaces on the dialysis machine monitor to be disinfected and their disinfection status as monitored by the disinfection sensors.

[0014] Figure 3A Shown is a portion of a disinfection sensor that can be attached to a surface to be disinfected.

[0015] Figure 3B A portion of the surface to be disinfected configured for mounting a sensor is shown.

[0016] Figure 3C A cross section of a portion of a disinfection sensor mounted at a surface to be disinfected is shown.

[0017] Figure 4 A view of the disinfection sensor from the outer surface is shown.

[0018] Figure 5 Another embodiment of a disinfection sensor is shown as seen from the exterior surface.

[0019] Figure 6 A cross-section of a portion of a second embodiment of a disinfection sensor mounted at a surface to be disinfected is shown.

[0020] Figure 7 A block diagram of an exemplary computer system is shown.

[0021] Figure 8 An integrated capacitive touch screen is shown.

[0022] Like reference numerals in the various drawings represent like elements. DETAILED DESCRIPTION

[0023] Disclosed is an integrated system that can determine whether durable medical devices, such as dialysis machines (e.g., hospital dialysis machines, home dialysis machines, etc.), have been properly disinfected. The system can detect and record disinfection that occurred, determine the disinfectant used, determine the dwell time the disinfectant soaked the machine, determine when disinfection occurred, determine which parts of the machine were disinfected, determine who disinfected the machine, and so on. This information allows the medical device to provide clear instructions, such as alerts, and require implementation of appropriate disinfection protocols. This information can be used to ensure that employees adhere to their training and can also be used to conduct audits of disinfection practices.

[0024] Figure 1A highly schematic dialysis system 100 (e.g., a hemodialysis system or a peritoneal dialysis system) is shown in which dialysis solution is moved from a dialysate module 120 to a dialysis machine 110 including a dialyzer 140 under the force of at least one pump 105. Once through the dialyzer 140, in some cases, the dialysate passes through a sorbent device 130 within the dialysate module 120, and the recycled dialysate solution exits the sorbent device 130 and is moved back to the dialysis machine 110. In some cases, there is no sorbent device 130, and spent dialysate produced in the dialysate module 120 and having passed through the dialyzer 140 is directed to a waste container or drain system 160. A controller 150 controls the functions of the dialysate module 120.

[0025] As the dialysis solution passes through the dialyzer 140 in the dialysis machine 110, toxins are transferred from the patient's blood into the dialysis solution, forming spent dialysis solution. This process can be repeated until the desired amount of toxins is removed from the patient's blood.

[0026] Figures 2A-2D Various portions of the dialysis machine 110 are shown that may include small, unobtrusive disinfection sensors 210. These disinfection sensors 210 are placed at areas or locations 212 where surface disinfection is desired. Multiple disinfection sensors 210 are used because there are multiple critical locations 212 that need to be kept disinfected, and the system 100 monitors the disinfection status of all of these locations 212 via indications from the disinfection sensors 210. The locations 212 having disinfection sensors 210 include frequently touched surfaces as well as other surfaces. For example, these locations 210 may include surfaces such as touch screens ( Figure 2A ) of the dialysis machine monitor, dialysis machine panel ( Figure 2B ) and the side of the dialysis machine ( Figure 2C and 2D ). Location 212 can be selected as a location that is particularly important to keep clean (e.g., due to typical subsequent contact by a patient) or a place that is likely to become dirty (e.g., due to frequent contact).

[0027] Figures 3A-3C Shown are the components of the disinfection sensor 210. These components include an attachable portion 220 of the sensor 210 that attaches to the surface to be disinfected at each location 212, and a portion of the surface itself at location 212 that is configured to snap into engagement with the attachable portion of the disinfection sensor 210.

[0028] refer to Figure 3AEach disinfection sensor 210 has an attachable portion 220 that includes a small circuit board 230 with connected conductive pins or electrodes 240. The electrodes 240 serve as the contact points for the disinfection sensor 210 with the disinfection fluid used to clean the location 212. Two electrodes 240 are shown, but there can be one, three, four, or more such electrodes 240.

[0029] The attachable portion 220 of the disinfection sensor 210 may include a humidity sensor component 232, a conductivity sensor component 234, or both humidity and conductivity sensor components (e.g., Figure 3A (as shown). Circuitry for a moisture sensor component 232 and a conductivity sensor component 234 is located on the circuit board 230. When the dialysis machine 110 is disinfected by wetting its surface with liquid at location 212 with the disinfection sensor 210, the disinfection sensor 210 detects that the dialysis machine 110 is wet and / or detects the conductivity of the fluid via electrodes 240 in contact with the moisture sensor component 232 and / or the conductivity sensor component 234. The moisture sensor component 232 and / or the conductivity sensor component 234 on the circuit board 230 are connected to a computer, such as the controller 150. In some embodiments, the conductivity detected by the conductivity sensor component 234 can be used to determine the type of disinfectant being used, e.g., hydrogen peroxide, isopropyl alcohol solution, sodium hypochlorite, quaternary ammonium salts, etc. Each of these and other disinfectants is used at different concentrations, e.g., 10% hydrogen peroxide or 15%.

[0030] One factor that can cause high conductivity is residual disinfectant that remains on a surface and then re-wets it. For example, if a surface is wiped with a 0.6% sodium hypochlorite solution and then left to stand, the water will evaporate and leave residual solids. The next time the surface is wiped with a 0.6% sodium hypochlorite solution, the residual solids will enter the solution and produce a higher concentration of sodium hypochlorite solution. The measured conductivity will use a threshold that accounts for this accumulation. In some cases, the controller 150 may include an adaptive algorithm that learns and accounts for this accumulation.

[0031] Figure 3B shows how the surface of the dialysis machine 110 at each location 212 may be configured to Figure 3A An example of an attachable portion 220 mating is shown including a circuit board 230 with connected electrodes 240. Each location 212 includes a through hole 250 and a boss 252. Almost any surface of the dialysis machine 110, particularly a plastic surface, can be adapted to receive the Figure 3A Attachable portion 220.

[0032] Figure 3CThe cross-section depicts how the attachable portion 220 is mounted at any given location 212. A hole 250 on the surface of the dialysis machine mates with the electrode 240 of the attachable portion 220, and a boss 252 on the surface of the dialysis machine receives a screw 254. The screw 254 (e.g., a self-tapping screw) attaches the circuit board 230 to the surface of the machine at location 212 such that the electrode 240 protrudes through the hole 250 and is visible from (and in fluid contact with) an outer surface 256 of the machine at location 212. The electrode 240 can be flush (e.g., flat) with the outer surface 256. In some cases, the electrode 240 can protrude beyond the outer surface 256 such that a portion of the side of the electrode 240 extends beyond the outer surface 256 by a distance (e.g., less than 1 mm) without contacting the outer surface 256. The result is that the sensor 210 is in contact with and visible from the outer surface 256, as shown in FIG. Figure 4 shown.

[0033] The disinfection sensor 210 can include a moisture sensor component 232 configured to detect moisture on the outer surface 256 at a given location 212. The moisture sensor component 232 detects the presence of a fluid (e.g., a disinfectant) at the location 212. The disinfection sensor 210 can record the time when the liquid is detected and the time when the liquid is no longer detected. These times allow the controller 150 to calculate the residence time that the surface is wetted, e.g., the time in contact with the disinfection fluid.

[0034] In some cases, the controller 150 may include a stored time period in memory for comparison with the calculated dwell time. The stored time period may be equal to a known or recommended time for a surface to remain wetted by the disinfecting fluid for the surface to be considered clean or disinfected. The controller 150 is thus configured to detect that the fluid on the surface is wetted from an initial point in time and remains wetted and has not dried sufficiently for the disinfecting fluid to become inactive.

[0035] In some cases, the channel can be positioned in the outer surface 256 so that the sterilizing fluid is trapped in the channel. This arrangement ensures that evaporation does not cause the sterilizing fluid to not appear to meet the time threshold.

[0036] In some embodiments, the disinfection sensor 210 includes a conductivity sensor component 234. When wetted by the disinfection fluid, the electrode 240 records the change in conductivity read by the conductivity sensor component 234. Certain measured conductivity values ​​can be correlated with the presence of the disinfection fluid on the outer surface 256. The disinfection sensor 210 can record the time when a change in conductivity, thereby detecting the disinfection fluid, is detected, and the time when the disinfection fluid is no longer detected. These times allow the controller 150 to calculate the residence time that the surface is in contact with the disinfection fluid.

[0037] In some cases, the controller 150 may include in memory a stored time period to compare with the calculated dwell time. The stored time period may be equal to a known or recommended time for a surface to remain wetted by the disinfecting fluid for the surface to be considered clean or disinfected.

[0038] In some embodiments, the controller 150 can correlate the conductivity value measured by the disinfection sensor 210 with the conductivity of known disinfection fluids. For example, the controller 150 can include a memory that stores a lookup table containing conductivity values ​​for a series of commonly used disinfectants (e.g., bleach). By comparing the measured conductivity value with the stored conductivity values, the controller 150 can determine which disinfection fluid was used.

[0039] The concentration of the disinfectant fluid changes as the applied fluid dries and evaporates from the outer surface 256. The controller 150 may include information correlating conductivity measurement ranges with known disinfectant fluids. In some cases, the disinfectant fluid used may be selected so that the required dwell time is short, for example, less than 3 minutes. In such cases, the conductivity measurement is not affected during the surface wetting period because not enough water evaporates to change the concentration of the disinfectant fluid.

[0040] In some cases, the channel can be positioned in the outer surface 256 so that the sterilizing fluid is trapped in the channel. This arrangement ensures that evaporation does not cause the sterilizing fluid to not appear to meet the time threshold.

[0041] There may be multiple locations 212 on the dialysis machine 110. Some locations 212 will be horizontal, while some locations will not, and cannot, utilize gravity to fill the surrounding channels and hold the fluid in place while the conductivity measurement is taken. In such cases, a single conductivity reading may be taken at a single horizontal location. The remaining sensors at the other locations 212 may simply be wetted, and the system may assume the same disinfectant and dwell time as at the horizontal representative locations.

[0042] Figure 4 A view of the disinfection sensor 210 is shown as seen from the outer surface 256. In this example, only the ends of the electrodes 240 are visible on the outer surface 256.

[0043] Figure 5 and 6An alternative configuration for mounting a disinfection sensor 270 is shown, viewed from the outer surface 256 and in cross-section. Disinfection sensor 270 is similar to disinfection sensor 210 described above, with like reference numerals representing like components. However, disinfection sensor 270 includes an additional fluid channel 260 at the location 212 to be disinfected in the outer surface 256 of machine 110. Channel 260 is a blind hole and is located in fluid communication with the end of electrode 240. Channel 260 is configured so that disinfection fluid applied to surface 256 will accumulate or be trapped in channel 260. This configuration ensures that sufficient disinfection fluid will be available to electrodes 240 so that they can detect the presence of disinfection fluid (via humidity or conductivity changes, or both). In some cases, channel 260 can ensure that the presence of disinfection fluid does not change its concentration over the residence time required for successful disinfection of outer surface 256. Although channel 260 is illustrated as a single linear channel, other configurations are possible. For example, the channel may intersect each electrode 240 of the disinfection sensor 210 individually, or have a different shape than shown (eg, circular).

[0044] The information collected by the disinfection sensor 210 can be used to determine and alert the user that the dialysis machine 110 has been disinfected. The controller 150 can determine whether the appropriate disinfectant was used, the appropriate dwell time was used, the machine was disinfected in all designated locations, the machine was disinfected at the correct intervals, and trained personnel disinfected the machine. Information stored in the machine can also be used for audit purposes.

[0045] The user interface can inform the user whether the machine is clean, as determined by the disinfection sensor 210 and the controller 150. The indication of the disinfection status of a particular location 212 can indicate, for example, "clean" or "not clean." If the appropriate disinfection fluid is detected within the appropriate dwell time and within a given time interval (e.g., every hour, between treatments, end of day), the particular location 212 can be indicated as "clean." The main display screen of the machine (e.g., Figure 2A The disinfection status can be displayed as part of the user information displayed. The disinfection status can be displayed in a variety of ways, such as a traffic light (red, yellow, green), a "not clean" light, or a message indicating that it is not disinfected.

[0046] In some embodiments, the disinfection status can be localized to each location 212. For example, a light, such as an LED light, can be integrated into each sensor 210 (e.g., on the circuit board 230). If the controller 150 has determined whether a particular disinfection location 212 is clean or dirty, the light can change state, for example, by turning on or off, or by changing color. In some cases, when the sensor 210 detects the presence of disinfection fluid (through a change in conductivity and / or through humidity), the light at the sensor location can change to indicate the start and end of disinfection. For example, the light change may be turning on or off, or changing color.

[0047] In some embodiments, the memory within the controller 150 may include recommended cleaning intervals for the machine. The machine may alert the user that the machine or machine components require cleaning. The recommended cleaning intervals may be different for different locations 212. The machine may record when disinfection occurred (between treatments, at the end of the day, at the beginning of the day, etc.). In some cases, the machine may record who performed the disinfection, for example, by requiring the user to enter a password, card reader, facial recognition, etc. If disinfection practices are audited, this information may also be stored and provided.

[0048] The machine may issue an indication such as an alarm and require implementation of an appropriate disinfection protocol, ensuring that employees are trained in cleaning protocols. In some cases, the controller 150 may prevent the use of the machine if it is determined that the machine is not clean.

[0049] Figure 7 A block diagram of an exemplary computer system 700 is shown. Figure 1 The controller described may be an example of the system 700 described herein. Thus, the system 700 may be Figure 1 The system 700 is a part of a dialysis machine and can be configured to help manage disinfection information. For example, the system 700 can determine information related to disinfection and be used to view alarms, logs, etc. related to such disinfection.

[0050] System 700 includes a processor 710, a memory 720, a storage device 730, and an input / output device 740. Each of components 710, 720, 730, and 740 can be interconnected, for example, using a system bus 750. Processor 710 is capable of processing instructions for execution within system 700. Processor 710 can be a single-threaded processor, a multi-threaded processor, or a quantum computer. Processor 710 is capable of processing instructions stored in memory 720 or on storage device 730. Processor 710 can perform operations such as causing the dialysis system to perform functions related to dialysis treatment and determining information related to disinfection.

[0051] The memory 720 stores information within the system 700. In some embodiments, the memory 720 is a computer-readable medium. The memory 720 can be, for example, a volatile memory unit or a non-volatile memory unit. In some embodiments, the memory 720 stores information related to treatments to be administered to a patient and information related to past and / or current sterilizations (e.g., a log).

[0052] Storage device 730 can provide mass storage for system 700. In some embodiments, storage device 730 is a non-transitory computer-readable medium. Storage device 730 may include, for example, a hard disk drive, an optical disk drive, a solid-state drive, a flash drive, a magnetic tape, or some other mass storage device. Storage device 730 may alternatively be a cloud storage device, for example, a logical storage device comprising multiple physical storage devices distributed across a network and accessed using the network. In some embodiments, information stored in memory 720 may also or alternatively be stored on storage device 730.

[0053] The input / output device 740 provides input / output operations for the system 700. In some embodiments, the input / output device 740 includes one or more of a network interface device (e.g., an Ethernet card), a serial communication device (e.g., an RS-23210 port), and / or a wireless interface device (e.g., a short-range wireless communication device, an 802.11 card, a 3G wireless modem, or a 4G wireless modem). In some embodiments, the input / output device 740 includes a driver configured to receive input data and send output data to other input / output devices, such as a keyboard, a printer, and a display device (e.g., a touch screen 106). In some embodiments, mobile computing devices, mobile communication devices, and other devices are used.

[0054] In some embodiments, system 700 is a microcontroller. A microcontroller is a device that contains multiple components of a computer system in a single electronic package. For example, a single electronic package may contain a processor 710, a memory 720, a storage device 730, and an input / output device 740.

[0055] Although already Figure 7An exemplary processing system is described in the specification, but embodiments of the subject matter and functional operations described above may be implemented in other types of digital electronic circuitry, including the structures disclosed in this specification and their structural equivalents, or in computer software, firmware, or hardware, or a combination of one or more thereof. Embodiments of the subject matter described in this specification may be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible program carrier (e.g., a computer-readable medium) for execution by a processing system or for controlling the operation of the processing system. A computer-readable medium may be a machine-readable storage device, a machine-readable storage carrier, a memory device, a composition of matter that implements a machine-readable propagated signal, or a combination of one or more thereof.

[0056] The term "computer system" may encompass all devices, apparatus, and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, a processing system may also include code that creates an execution environment for the computer program in question, for example, code constituting processor firmware, a solution stack, a database management system, an operating system, or a combination of one or more of these.

[0057] A computer program (also referred to as a program, software, software application, script, executable logic, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file containing other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or portions of code). A computer program can be deployed to execute on one computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communications network.

[0058] Computer-readable media suitable for storing computer program instructions and data include all forms of nonvolatile or volatile memory, media, and storage devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks or magnetic tapes; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated into, special purpose logic circuitry. The components of the system may be interconnected by any form or medium of digital data communication, such as a communication network. Examples of communication networks include local area networks ("LANs") and wide area networks ("WANs"), such as the Internet.

[0059] In some embodiments, the device may utilize a touch screen. Several touch screen technologies exist, one of which is capacitive. A capacitive touch screen panel has an insulator, such as glass, coated with a transparent conductor, such as indium tin oxide (ITO). Since the human body is also a conductor of electricity, touching the screen surface causes the screen's electrostatic field to be distorted. The electric field distortion caused by a person touching the screen surface can be measured as a change in capacitance. Various techniques can be used to determine the location of the touch. This location is then sent to controller 150 for processing.

[0060] Different disinfectant fluids are also electrical conductors. The conductivity of different disinfectants may have different conductivity levels, causing the distortion of the screen's electrostatic field to vary depending on the conductivity of the fluid placed on it. In addition, a small channel (e.g., channel 260) that collects the fluid can be placed near the capacitive touch screen so that a known amount of fluid can be collected therein. The channel must be easy to clean.

[0061] Figure 8 An example of an integrated capacitive touchscreen is a transparent shelf built into the door, with a pocket for the capacitive touchscreen. A circuit board and battery can be placed underneath, accessible through a small plastic door. The capacitive touchscreen and the plastic shelf have similar optical properties and can be bonded together using an optically clear adhesive with similar optical properties to the touchscreen and shelf. A capacitive keyboard can be integrated into the door, sensing the capacitance of the keyboard / touchscreen itself and determining whether the capacitive touch area of ​​the keyboard is wet.

[0062] Two electrodes 240 are shown, but one, three, four, or more electrodes 240 may be used. Using two, three, or four contacts to determine conductivity measurements depends on the cell constant. A consistent amount of fluid to be measured is a factor in determining the cell constant, as is the spacing between the electrodes. By molding a small, accurate, cleanable channel into the machine's plastic, a known amount of disinfectant can be filled into the channel, allowing for a repeatable cell constant and, therefore, accurate conductivity measurement. Once a known conductivity is determined, it can be compared to a table of disinfectants with known conductivity. For example, with two electrodes, the spacing between the centerlines of the electrodes is a highly accurate representation of the volume of fluid captured in the channel. The dimensions, material, surface finish, and other characteristics of the electrodes are known. Knowing these characteristics allows the cell constant to be determined. The channel can also be cleaned so that no residual fluid affects subsequent measurements.

[0063] When using a capacitor, the repeatability of the fluid being measured affects the conductivity measurement. The capacitor creates field lines, and if a repeatable path is created next to the capacitor, the interruption of the field lines will also be repeatable and therefore measurable.

[0064] If the specific conductivity is not important to the system's modality, the system only needs to determine whether the channel is wetted and how long it has been wetted. In such an embodiment, the accuracy of the channel is less of a factor in determining the measurement value.

[0065] A number of embodiments of the present invention have been described. However, it will be appreciated that various modifications can be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims

1. A medical system comprising: a dialysis machine having at least one exterior surface to be disinfected at a given location; At least one disinfection sensor connected to the dialysis machine at a given location, said disinfection sensor comprising: two or more electrodes in fluid contact with the outer surface of the dialysis machine, and a conductivity sensor component in electrical contact with the two or more electrodes, the conductivity sensor component being configured to transmit an electrical signal indicative of the conductivity of a fluid located on an exterior surface of the dialysis machine and in contact with the two or more electrodes; a processor configured to receive the electrical signal and thereby determine a disinfection status of a given location; and A user interface configured to indicate the disinfection status of a given location.

2. The medical system according to claim 1, wherein: Determining the disinfection status of a given location includes determining whether the conductivity signal indicates that the liquid on the exterior surface of the dialysis machine is a disinfecting fluid.

3. The medical system according to claim 2, wherein: Determining whether the conductivity signal indicates that the liquid on the exterior surface of the dialysis machine is a disinfecting fluid includes comparing the conductivity signal to a conductivity signal stored in a memory connected to the processor.

4. The medical system according to claim 2 or 3, wherein: Determining the disinfection status of a given location includes determining the time interval during which disinfection fluid is present on the exterior surface of the dialysis machine.

5. The medical system according to claim 4, wherein: Determining the disinfection status of a given location includes comparing the time interval to a threshold time interval.

6. The medical system according to claim 2 or 3, wherein: Determining the disinfection status of a given location includes identifying disinfection fluid present on an exterior surface of the dialysis machine.

7. The medical system according to any one of claims 1 to 3, wherein: The user interface is configured to alert the user that the dialysis machine requires cleaning.

8. The medical system according to any one of claims 1 to 3, wherein: The medical system also includes a memory for storing a disinfection log.

9. The medical system according to any one of claims 1 to 3, wherein: The medical system also includes a cleanable channel on an exterior surface of the dialysis machine that collects a known amount of fluid.

10. A method comprising: receiving, at a processor, a signal from a conductivity sensor indicative of conductivity of a liquid on an exterior surface of the dialysis machine at a given location and in fluid contact with an electrode of the conductivity sensor; determining a disinfection status of an exterior surface at a given location; and The disinfection status of the exterior surface at a given location is displayed on the user interface.

11. The method according to claim 10, wherein: Determining the disinfection status of a given location includes determining whether the conductivity signal indicates that the liquid on the exterior surface of the dialysis machine is a disinfecting fluid.

12. The method according to claim 11, wherein Determining whether the conductivity signal indicates that the liquid on the exterior surface of the dialysis machine is a disinfecting fluid includes comparing the conductivity signal to a conductivity signal stored in a memory connected to the processor.

13. The method according to claim 12, wherein: Determining the disinfection status of a given location includes determining the time interval during which disinfection fluid is present on the exterior surface of the dialysis machine.

14. The method according to claim 13, wherein Determining the disinfection status of a given location includes comparing the time interval to a threshold time interval.

15. The method according to any one of claims 12 to 14, wherein Determining the disinfection status of a given location includes identifying disinfection fluid present on an exterior surface of the dialysis machine.

16. The method according to any one of claims 10 to 14, wherein: The method includes alerting a user that the dialysis machine requires cleaning.

17. The method according to any one of claims 10 to 14, wherein The method includes storing a disinfection log in a memory.

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