title: Activation of the clotting system: heparin-coated versus non coated systems for extracorporeal circulation.
abstract: The purpose of this experimental study was to compare heparin-coated versus non-coated systems for extracorporeal membrane oxygenation (ECMO), to investigate the dynamic course of clotting activation in both groups.
  
  
  METHODS
  Eight pigs weighing 19.7 (+/- 1.3) kg, each underwent ECMO for 24 hours. Two groups were formed: in group 1, heparin-coated circuits were used with low dose heparinization (10 IU/kg/hr), whereas in group 2 non-coated circuits with high dose heparinization (60 IU/kg/hr) were used. Coagulation was monitored by measuring prothrombin time, partial thromboplastin time, fibrinogen, antithrombin III (AT III) and specific markers of clotting activation (thrombin-antithrombin III complexes (TAT) and D-dimer). Furthermore, platelet count, hematocrit, activated clotting time (ACT), and plasma heparin concentration were determined regularly
  
  
  RESULTS
  The dynamic course of the specific coagulation activation markers showed some differences: whereas TAT and D-dimer increased quickly in group 2, the increase in group 1 was delayed. Activation marker values tended to be lower in group 1 during the first six hours, after which no more differences between the groups were seen. After 24 hours of ECMO, TAT and D-dimer had nearly returned to baseline values. Platelets showed a continuous decrease throughout the experiment, which was very similar in both groups.
  
  
  CONCLUSIONS
  The heparin coated system showed a distinct delay in clotting activation during the first six hours of ECMO. After six hours there were no more differences between the groups.
authors.affiliation: ECMO Center Graz (Department of Neonatology), University of Graz, Austria. berndt.urlesberger@kfunigraz.ac.at
authors.forename: B
authors.initials: B
authors.lastname: Urlesberger
authors.forename: G
authors.initials: G
authors.lastname: Zobel
authors.forename: S
authors.initials: S
authors.lastname: Rödl
authors.forename: D
authors.initials: D
authors.lastname: Dacar
authors.forename: I
authors.initials: I
authors.lastname: Friehs
authors.forename: B
authors.initials: B
authors.lastname: Leschnik
authors.forename: W
authors.initials: W
authors.lastname: Muntean
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D000990:Antithrombin III / Q000032:analysis; D001672:Biocompatible Materials; D001777:Blood Coagulation / Q000187:drug effects*; D015199:Extracorporeal Membrane Oxygenation; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006400:Hematocrit; D006493:Heparin / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008567:Membranes, Artificial; D010314:Partial Thromboplastin Time; D010447:Peptide Hydrolases / Q000032:analysis; D010976:Platelet Count; D011517:Prothrombin Time; D013552:Swine
chemical_list: D000925:Anticoagulants; D001672:Biocompatible Materials; D008567:Membranes, Artificial; C046193:antithrombin III-protease complex; D000990:Antithrombin III; D005340:Fibrinogen; D006493:Heparin; D010447:Peptide Hydrolases