Serial changes in primary hemostasis after massive transfusion.

Primary hemostasis was studied in 22 injured patients in the operating room (OR) after a minimum of 10 transfusions, 6 and 15 hours after surgery, on postoperative days 2 and 4 and during convalescence (mean 25 days after surgery). The platelet count was low in the OR and continued to fall after surgery through the second postoperative day; it began to rise by day 4 and was above normal at convalescence. Most patients had prolonged bleeding time through day 4. Platelet aggregation with adenosine diphosphate and collagen was depressed in the OR and platelet aggregation remained depressed. The platelet-specific proteins, beta-thromboglobulin and platelet factor 4, were elevated in the OR and fell throughout the first 4 postoperative days. A secondary rise in these proteins occurred at convalescence. Despite severe alterations in both the number and function of platelets after massive transfusion for injury, no patient had clinical oozing. Therefore the routine administration of platelets in comparable patients without "medical bleeding" is unwarranted.