The function of the dialysis system is to eliminate toxic wastes products, to restore “internal milieu composition” and to correct extracellular fluid overload. When complete renal failure occurs, the use of an artificial kidney is required. An artificial kidney is a machine that provides a means for removing uremic toxins from the blood and adding deficient components to it (e.g., bicarbonate, calcium). This is done using the principle of dialysis. There are two types of dialysis treatment: peritoneal dialysis (PD) and hemodialysis (HD). The peritoneal dialysis (PD) uses the abdominal cavity and its largely perfused serous membrane as a “built-in dialyzer” by creating and renewing periodically an artificial ascites. PD is a simple and safe technique that does not imply an extracorporeal blood circuit and usually performed at home. The hemodialysis and its related techniques are a much more complex and risky procedure that requires an extracorporeal blood circuit. HD is usually performed in hemodialysis facilities (center, self-care) but may be alternatively performed at home after training.
Hemodialysis machines deliver a patient’s dialysis prescription by controlling blood and dialysate flows through the dialyzer. In addition, they incorporate monitoring and alarm systems that protect the patient against adverse events that may arise from equipment malfunction during the dialysis treatment. This chapter will focus on essential principles of hemodialysis, the major components of HD machines and their respective monitoring devices.