Abstract: The wear on components in a dialysis machine is analyzed for the purpose of making repair and maintenance decisions. The actual performance of components is used to establish a test value. The test value is compared to a threshold value which represents the limits of normal performance of the component. Each instance where the test value exceeds the threshold value is counted and a maintenance count value is developed. The maintenance count value represents the number of abnormal performance events, and the maintenance count value is used to make maintenance and repair decisions. The test value developed for each component varies according to the type of component. The maintenance count values may be displayed for use by service personnel.

Abstract: Information is entered and validated by the operator of a dialysis machine by converting the entered information into a first form using a first conversion relationship such as ASCII. The information in the first form is next converted into a second form using a second conversion relationship, such as floating point numeric. Thereafter the information in the second form is converted back to the first form using the first conversion relationship. The information in the first form which resulted from the third conversion is displayed for acceptance for rejection by the operator. The multiple sequential conversions indicate the proper functionality of a safety system of the dialysis machine. Displaying the information resulting from sequential multiple conversions assures an opportunity for the operator to evaluate the entries for accuracy. Re-display of the previously entered information repeatedly presents the operator with an opportunity to recognize human-induced errors.

Abstract: A dialysis machine uses a single microcontroller to perform both safety system functions and control system functions. A single segmented memory records the safety system code and data separately and in isolation from the control system code and data. Access to the safety system software is limited to the operating system and safety system contexts. A protected mode of operation of an embedded processor allows recovery of a state vector upon failures of the operating system, the safety system and the control system. The operating system allows recovery of a state vector upon failure of the safety system and the operating system. A watchdog timer circuit places the dialysis machine in a safe patient state if a total failure of the microcontroller occurs.

Abstract: A graphical operator machine interface for a dialysis machine and a method of graphically programming the dialysis machine involves graphically accessing substantially all typical machine operating and dialysis treatment parameters employed in a typical dialysis treatment, and graphically entering selections with respect to each of the selected parameters. The selections of the individual parameters establish display screens which individually present the selected parameters. The selections of the individual parameters also allow the operator to establish values for those selected parameters. The parameters include those involved for setup of the machine for dialysis treatment, those monitored during treatment, the alarm limits established during the treatment, and parameters which allow the automatic initiation of machine functionality prior to the use of the machine for treatments.

Abstract: A technique for automatically cleaning, disinfecting and otherwise preparing a dialysis machine includes a method and apparatus for programming the dialysis machine to awaken from a reduced power mode at a predetermined time and perform one of several wake-up procedures (e.g., rinsing, dialysate preparation, or hot water or chemical disinfection). A wake-up time and a corresponding wake-up procedure is preferably programmed for each day of the week. If disinfection is programmed, the machine wakes up at the predetermined time to heat the water or mix the chemicals before pumping the cleaning/disinfecting liquid through the dialysis machine. The machine then rinses the cleaning/disinfecting liquid down a waste drain. If a chemical solution is utilized, the dialysis machine may be programmed to allow the chemical solution to dwell within the dialysis machine for a predetermined period before rinsing it down the drain.