General Medical Information

Platelet Abnormalities

David M. Barrs

Thrombocytopenia is defined as a platelet count of less than 140,000/µL. Counts less than 50,000/µL may be associated with bleeding problems during surgery. In the urgent situation, platelet transfusions should be performed to raise the platelet count to over 50,000/µL. Each unit of platelets will raise the platelet count 5,000 to 10,000/µL, and the platelet half-life is usually 2 to 3 days unless there is increased destruction. Ideally, the platelet count should be maintained above 50,000/µL for 3 to 4 days postoperatively. Thrombocytopenia developing in the postoperative period is unusual unless massive transfusion has been necessary, but sepsis, disseminated intravascular coagulation (DIC), and drug-induced thrombocytopenia must be considered.

Qualitative platelet disorders with abnormalities in platelet function may exist even with a normal platelet count. If a patient has a history of uremia, liver disease, or abnormal bleeding from previous surgery or if there is a recent history of ingestion of aspirin, nonsteroidal antiinflammatory drugs (NSAIDs), or other medicine that may affect platelet function, a bleeding-time test should be performed. Bleeding times longer than 10 minutes are considered abnormal, and the urgency of surgery must be considered. With minor elevations and in surgical sites where bleeding is easily controlled, surgery may proceed if platelets are available. If the bleeding time is longer than 20 minutes, elective surgery should be canceled. Platelet transfusions or administration of desmopressin acetate should be performed if emergency surgery is necessary.