Blood treatment systems and methods

Abstract

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 The FPGA may be configured to monitor an amount of ultrafiltration fluid withdrawn from a patient during dialysis treatment and to enter a fail-safe state if a maximum amount is exceeded.