a. intermittently withdrawing and infusing the blood from and to a blood flow passage in the extracorporeal circuit via a single venous access to a mammalian patient;

b. applying an algorithm to maximize withdrawal rate;

c. detecting a withdrawal blood vessel occlusion;

d. stopping the withdrawal of blood if the occlusion occurs and relieving a vacuum caused by the occlusion by opening an shunt to a blood reservoir to allow blood in the reservoir to flow into the blood flow passage of the circuit:

e. if the occlusion does not open within a predetermined time period, reversing the withdrawal pump to create flow through the blood flow passage to the occluded vessel;

f. if the occlusion does not open within a second predetermined time period, infusing a volume of blood using the infusion pump;

g. resuming withdrawal until the blood reservoir is filled by a predefined volume of blood;

h. stopping the withdrawal;

i. starting infusion of the blood from the reservoir through blood treatment modules and a heat exchanger into the blood vessel;

j. applying an algorithm to maintain a predefined infusion pressure;

k. when controller detects that the reservoir is empty, infusion stops and step (b) is resumed.