Blood platelets and extracorporeal circulation; kinetic studies on dogs on cardiopulmonary bypass.

Platelet kinetics and functions were studied in dogs during extracorporeal circulation. A transient platelet sequestration in the liver occurs during the bypass. This reversible disappearance is accompanied by a loss of the ability of platelets to adhere or aggregate. The platelets which return to the circulation have normal functions and a normal life span. The irreversible damage is mainly due to the direct blood-gas interface. Impairment of lung function by platelet aggregates is discussed and the importance of an in vivo model to study the factors which affect the platelets, such as antiaggregating agents, is pointed out.