Extracorporeal circulation can induce hypotension by both blood-material contact and pump-induced platelet aggregation.
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.
Borgdorff
P
P
Laboratory for Physiology, Institute for Cardiovascular Research Vrije Universiteit (ICaR-VU), Amsterdam, The Netherlands. p.borgdorff.physiol@med.vu.nl
van den Bos
G
G
Tangelder
G J
GJ
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
D001672:Biocompatible Materials