Thrombocytopenia is defined as a platelet count less than 150 × 103 cells/μl. Five to ten percent of patients will be thrombocytopenic preoperatively, and an unknown number will develop thrombocytopenia in the perioperative period. Perioperative thrombocytopenia is usually caused by hemodilution and consumption, but can also be the result of antiplatelet therapy, heparin, other medications, decreased production, increased sequestration, immune destruction, and laboratory artifact. Any degree of preoperative thrombocytopenia is associated with higher odds of transfusion, complications, long-term care, readmission, reoperation, and death in a dose-dependent fashion, and patients who require platelet transfusion also have a higher odds of red cell transfusion, reoperation, and death.
One in three of cases of platelet refractoriness is associated with alloimmunization against donor platelet antigens. The most common alloantibodies are against human leukocyte antigens A or B, and are usually seen in multiparous or multiply transfused patients. Platelet crossmatching, selecting donors with the same antigen phenotype as the patient, or selecting donors who lack the cognate antigens to the patient's antibodies can produce improved platelet increments. All these techniques require additional time and expertise, and advance consultation with transfusion medicine specialists is usually necessary.
Anesthesiology. 2021;134(3):471-479. © 2021 American Society of Anesthesiologists | Lippincott Williams & Wilkins