Prophylactic Platelet Transfusions Before Percutaneous Procedures
A normal platelet count is much higher than what is required for successful thrombin generation and maintenance of endothelial integrity at rest. Based on large trials in hematological malignancies, the risk of clinically significant bleeding is modest and constant down to a platelet count of 10 × 103 cells/μl, and prophylactic platelet transfusions to prevent spontaneous bleeding are usually not necessary above a platelet count of 5 to 10 × 103 cells/μl.[9,35]
Data for prophylactic platelet transfusions before percutaneous procedures are sparse. One small trial and a few larger observational studies suggest that central lines placement by experienced providers is low-risk at platelet counts greater than or equal to 10 to 20 × 103 cells/μl.[12,36] For high-risk procedures such as liver biopsy, the Society of Interventional Radiology (Fairfax, Virginia) recommends a transfusion threshold of less than 50 × 103 cells/μl because observational studies found a slightly increased risk of bleeding below this level. The AABB (formerly the American Association of Blood Banks; Bethesda, Maryland) recommends platelet transfusion before lumbar puncture for patients with a platelet count less than 50 × 103 cells/μl, and the American Society of Clinical Oncology (Alexandria, Virginia) recommends a threshold of 50 × 103 cells/μl for lumbar puncture in newly diagnosed pediatric patients with leukemia and 20 × 103 cells/μl for stable pediatric patients.[38,39]
All society guidelines regarding platelet counts before percutaneous procedures are weak recommendations based on low-quality evidence. They are also conservative: a review of 5,223 consecutive lumbar punctures in 958 children at a pediatric cancer center, including 199 children with counts less than 20 × 103 cells/μl, found an increase in the proportion of traumatic punctures, but not one serious complication. A Danish cohort of 64,730 patients undergoing 83,711 lumbar punctures found that the hematoma rate was relatively constant around 0.2%, regardless of platelet count, although these results may be biased by patient selection. There is no good evidence that preprocedural platelet transfusion reduces the risks of severe complications, and providers frequently fail to verify the results before starting the procedure.
Anesthesiology. 2021;134(3):471-479. © 2021 American Society of Anesthesiologists | Lippincott Williams & Wilkins