Patent attributes
Dialysis systems are disclosed comprising new fluid flow circuits. Systems may include blood and dialysate flow paths, where the dialysate flow path includes balancing, mixing, and/or directing circuits. Dialysis systems may include a safety system utilizing a field programmable gate array (FPGA) that monitors at least conductivity and temperature of dialysate in the flow circuit upstream of a dialyzer and enters a fail-safe state if the measured conductivity is outside of a range of values. The FPGA may be verified to be operating properly by exposing sensors in fluid paths to temperatures or conductivities that are outside pre-determined permissible ranges of values, and confirming that the FPGA safety system enters a fail-safe state in response to the temperatures or conductivities. The FPGA may be configured to monitor an amount of ultrafiltration fluid withdrawn from a patient during dialysis treatment and to enter a fail-safe state if a maximum amount is exceeded.
