title: Extracorporeal circulation can induce hypotension by both blood-material contact and pump-induced platelet aggregation.
abstract: OBJECTIVE
  Use of extracorporeal systems in cardiopulmonary bypass and dialysis induces vascular reactions, which can lead to hypotension and lung edema.
  
  
  METHODS
  To study the contribution of blood-material contact and use of a roller pump, as well as prevention of their adverse effects, we perfused a rat hind leg with a tube connecting a carotid and a femoral artery.
  
  
  RESULTS
  Autoperfusion of an uncoated tube caused a fall of aortic pressure and femoral resistance to 66% +/- 16% and 76% +/- 15%, respectively, of their initial values within 2 hours, whereas in control animals without a shunt, these variables hardly changed (to 94% +/- 2.8% and 99% +/- 2.8%, respectively). Lung water content became significantly higher than that found in control animals (79.4% +/- 1.50% versus 77. 0% +/- 1.67%). If we coated the tube with albumin, these changes were largely prevented. When the coated tube was placed in a roller pump, aortic pressure and femoral resistance immediately fell to 79% +/- 17.2% and 63% +/- 13.5%, respectively, whereas lung water content did not increase. The vasodilation was caused by platelet aggregation and could be prevented with aurintricarboxylic acid, which inhibits shear-induced platelet aggregation by blocking the binding of von Willebrand factor to platelet glycoprotein Ib receptors.
  
  
  CONCLUSIONS
  Extracorporeal circulation may induce hypotension and lung edema by means of blood-material contact. Hypotension can be prevented by coating the system with albumin but can still result from pump-induced platelet aggregation.
authors.affiliation: Laboratory for Physiology, Institute for Cardiovascular Research Vrije Universiteit (ICaR-VU), Amsterdam, The Netherlands. p.borgdorff.physiol@med.vu.nl
authors.forename: P
authors.initials: P
authors.lastname: Borgdorff
authors.forename: G
authors.initials: G
authors.lastname: van den Bos
authors.forename: G J
authors.initials: GJ
authors.lastname: Tangelder
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D001769:Blood; D004487:Edema / Q000209:etiology; D005112:Extracorporeal Circulation / Q000009:adverse effects*; D007022:Hypotension / Q000209:etiology*; D007260:Infusion Pumps; D008297:Male; D010974:Platelet Aggregation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001672:Biocompatible Materials