The equipment detects a blockage or stenosis in a fistula connected to an external blood circuit for hemodialysis by determining the presence of absence of a pulse. Blood in the patients body circulates from the right side of the patients heart (101) through the lungs (102) to the left side of the heart (103) and from there to the aorta and a pressure sensor (10(MAP)) monitors the blood pressure. Blood from a peripheral artery (105) in the patients arm passes through an anastomosis (106) to a connection (107) to a vein, and there is a pressure sensor (20(CVP)) on the Vena Cava. Blood may be taken from this circuit (201) past a meter (40(PF(a))) and a further (44) a blood pump (200), another meter (45) and a dialysis machine. The blood passes through a venous drop chamber (244) and a line back to a connection (203) with the vein connection line and a pressure meter (42(PF(v))).
