- Complications Of Blood Administration

Coagulopathy:

There's a handful of reasons that a blood transfusion can cause clotting problems.  The foremost is that when blood is not super-fresh (< 24 hours old) it no longer contains any functioning platelets or clotting factors.  As if this alone was not bad enough, when the banked blood is mixed into the patients blood, the patient's own numbers of useable platelets and clotting factors becomes diluted, and therefore are less effective.  Next, the citrate that is used to prevent blood from coagulating binds to circulating calcium and can lead to hypocalcemia.  ...Low calcium can cause bleeding.  Also, cold blood transfusions can lead to hypothermia, which prolongs clotting time and facilitates bleeding.  Finally, as the patient's own body recognizes the depletion and dilution of its own clotting factors, intrinsic mechanisms of production increases.  This can in some cases lead to DIC.