title: Heparin monitoring and neutralization during cardiopulmonary bypass using a rapid plasma separator and a fluorometric assay.
abstract: Avoidance of over- or underheparinization during cardiopulmonary bypass (CPB) is crucial in preventing bleeding or clotting. Currently no completely satisfactory method is available for measuring heparin levels--a method that would be rapid, inexpensive, specific, and reproducible. We combined the use of two devices, a rapid plasma separator and a fluorometric heparin assay system, in an attempt to satisfy these requirements in 15 patients having CPB during cardiac surgical procedures. The first instrument separates plasma from whole blood using a pneumatic filtration principle, while the heparin assay system measures the effect of heparin on thrombin conversion of a synthetic fluorogenic substrate. Accurate plasma heparin levels can be generated in less than five minutes, and the assays are inexpensive and easy to perform. Performing heparin assays at critical intervals during CPB allowed desired heparin levels to be maintained and the protamine dose for heparin neutralization to be reduced to a minimum. In addition, studies for heparin rebound revealed negligible rebound up to six hours postoperatively despite the reduced doses of protamine. There were no hemorrhagic or clotting complications in the series.
mesh_terms: D002315:Cardiopulmonary Bypass; D005434:Flow Cytometry; D006493:Heparin / Q000008:administration & dosage / Q000097:blood*; D006801:Humans; D010314:Partial Thromboplastin Time; D010956:Plasmapheresis; D011479:Protamines / Q000008:administration & dosage
chemical_list: D011479:Protamines; D006493:Heparin