ABSTRACT
When a foreign body is brought into contact with blood, it is confronted with two complex biological systems, coagulation and immunity. Although these protective mechanisms are essential in man, they create problems when a foreign body is intentionally brought into contact with blood for medical purposes. However, since the early 1950s, polymers have been widely used for a large range of medical applications, from long-term implants to shortterm dressings, in all fields of medicine and surgery. Examples of practical devices that implicate blood contact polymers are (1):
Extracorporal blood-circulating devices Catheters Blood bags and tubing used for blood transfusion Membranes, hollow fibers, and tubing used for dialysis
devices, plasmapheresis and plasma detoxification, and oxygenators
Cardiac valves and blood vessel replacement such as aortic bypasses
Drug delivery systems Plasma expanders and blood substitutes Contrast agents Embolization agents
The medical use of such devices has increased during the second half of the 20th century due to improvements in the quality of the devices and that of the polymers used
to produce them. These polymers are increasingly prescribed for use in cardiac surgery and in the treatment of renal and cardiovascular disease. Without the use of polymers, some of the major improvements made in the past decades, in medical and surgical practice, would have been impossible.
