Hypothermia-induced platelet aggregation in human blood in an in vitro model: the dominant role of blood-material interactions.
Hypothermia-induced platelet aggregation (HIPA) with or without neutrophil involvement may cause neurologic dysfunction during hypothermic surgery. We report the use of a previously developed model to study the contributions of several surfaces, surface area, shear rate, and blood-material exposure time to HIPA. Heparinized (1.5 u/mL) human blood was quenched to 24 degrees C and passed (0.5 mL/min) through a 75-cm long 1/32" ID tubing of polyvinylchloride (PVC), polyethylene (PE), polyurethane (PU), Teflon-FEP, or heparin (Duraflo)-coated PVC. The number of aggregates was measured by a light-scattering method, and the concentration of occlusive aggregates was assessed using constant-pressure filtration (50 mmHg). No differences were seen among PVC, PE, PU, or Teflon-FEP. The heparin-coated PVC tubing produced fewer occlusive aggregates, and heparin leaching from the coating was not the cause of the decrease in occlusive aggregates. Increasing surface area increased the number of aggregates, and increasing shear rates decreased the occlusiveness of those aggregates.
Hall
Matthew W
MW
Department of Chemical Engineering, 350 CB, Brigham Young University, Provo, Utah 84602, USA.
Solen
Kenneth A
KA
D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology / Q000592:standards*; D001769:Blood / Q000187:drug effects / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D008954:Models, Biological; D010974:Platelet Aggregation / Q000187:drug effects*; D011108:Polymers / Q000494:pharmacology; D013314:Stress, Mechanical; D013997:Time Factors
D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D011108:Polymers; D006493:Heparin