Project Description: 

Dialysis is the most ubiquitous treatment for kidney failure, a condition that affects over 750,000 people in the U.S.. Current home hemodialysis options lack the ability to adjust dialysate composition to fit patients’ needs, and the premixed dialysate itself must be stored in heavy containers that pose a difficulty to elderly patients. We proposed a subsystem for Outset Medical’s Tablo home hemodialysis machine that would allow the device to adjust patients’ prescription at any time and eliminate the need for heavy jugs of dialysate. Our solution takes small concentrate packs of each of the components of dialysate and combines them with water to create dialysate during treatment. To accomplish this, our subsystem utilizes three peristaltic pumps operating at different speeds to pump a variable amount of dialysate components into a single line to be mixed with water. The peristaltic pumps are controlled by an arduino connected to a circuit and power supply. The arduino takes prescription input from the user on the computer and translates it into the three flow rates for the components, and adjusts the speeds of the pumps accordingly. We successfully established that our device fulfilled our design inputs, which were based on existing standards and interviews with patients and doctors. We proved that our pumps functioned appropriately at the flow rates needed for a given prescription by running the pumps at varying speeds set by the user. We then established that the final mix contained the proper ratios of the components through pH testing. Our tests produced dialysate with pH values within 2.6% of the correct values. In the future we plan to further test our completed system and integrate it into the overall Tablo infrastructure. We hope this device will make home hemodialysis easier for patients and improve their quality of life.