Tortuosity-powered microfluidic device for assessment of thrombosis and antithrombotic therapy in whole blood.

Accurate assessment of blood thrombosis and antithrombotic therapy is essential for the management of patients in a variety of clinical conditions, including surgery and on extracorporeal life support. However, current monitoring devices do not measure the effects of hemodynamic forces that contribute significantly to coagulation, platelet function and fibrin formation. This limits the extent to which current assays can predict clotting status in patients. Here, we demonstrate that a biomimetic microfluidic device consisting stenosed and tortuous arteriolar vessels would analyze blood clotting under flow, while requiring a small blood volume. When the device is connected to an inline pressure sensor a clotting time analysis is applied, allowing for the accurate measurement of coagulation, platelets and fibrin content. Furthermore, this device detects a prolonged clotting time in clinical blood samples drawn from pediatric patients on extracorporeal membrane oxygenation receiving anticoagulant therapy. Thus, this tortuosity activated microfluidic device could lead to a more quantitative and rapid assessment of clotting disorders and their treatment.

Neonatal transfusion models to determine the impact of using fresh red blood cells on inventory and exposure.

BACKGROUND: Data on age of blood and its impact on donor exposure and inventory in the paediatric setting are lacking. The standard of practice of reserving a specific red blood cell (RBC) unit for neonates who may require repeat transfusions is unique to the paediatric setting. Requiring transfusion of fresher RBC units may increase the exposure of neonates to multiple units and negatively affect the supply of fresh RBC. We constructed a transfusion model based on a 6 months of retrospective neonatal transfusion data at our institution. MATERIALS AND METHODS: All neonates (≤4 months old) at Texas Children's Hospital who received a RBC transfusion from June to November 2011 were included and RBC transfusion data were compiled. The age of blood at the time of each RBC transfusion was recorded. These data were reviewed to calculate exposure and inventory impact if each transfusion had been restricted to RBC either ≤7 or ≤14 days old at transfusion. RESULTS: A total of 216 neonates received 938 RBC transfusions. Of these, 393 (42%) were fresh RBC (≤14 days old), even without a required age guideline. Requiring fresh (≤14 days) RBC for all transfusions in this period would have resulted in 70 additional fresh units and one or more additional exposures in 44 patients. Requiring fresher (≤7 days old) RBC would have resulted in an additional 147 units and. one or more additional exposures in 54 patients. DISCUSSION: The more conservative model of fresh (≤7 days old) RBC would greatly increase fresh RBC inventory requirements, and 25% of transfused neonates would require additional RBC exposure. Based on retrospective data and the two transfusion models, it can be concluded that requiring RBC ≤14 days old for neonatal transfusion would best balance the use of fresher RBC with the smallest increase in patient exposure (20%) and minimum impact on the RBC inventory.