Figure 51-15 Plot of blood coagulation profile changes before, during, and after cardiopulmonary bypass (CPB) in 25 children. Clotting times and coagulant factors are shown as percent change from control. Stage I, baseline, before CPB; stage II, post-CPB, before protamine reversal of heparin; stage III, after protamine; stage IV, just prior to leaving the operating room; stage V, after 3 hours in the intensive care unit (ICU). PTT, partial thromboplastin time; PT, prothrombin time.