Blood surface interactions in extravascular salvageable blood pools.

Anticoagulation largely prevents clotting and defibrination in extravascular blood pools. Systemic or local heparin may be more effective than local citrate phosphate dextrose in preventing coagulation in extravascular blood, if there is to be a lag period greater than 60 minutes between blood loss and collection. Nonanticoagulated extravascular blood in the thorax or peritoneal cavity is completely defibrinated within 20 minutes and is a potential risk in large autotransfusions. Blood in the thorax is better preserved than peritoneal blood after local or systemic heparinization.