Isovolemic hemodilution with purified and polymerized bovine hemoglobin in a rabbit model of focal cerebral ischemia.
Isovolemic hemodilution with polymerized bovine hemoglobin (PoBH) was tested as a means of preventing infarction in a rabbit model of focal cerebral ischemia. The animals were divided into one control group and one hemodilution group. All animals underwent two hours of ischemia, caused by clipping the left internal carotid artery, the anterior cerebral artery, and the middle cerebral artery, followed by 4 hours of reperfusion. In the control group, the hematocrit was not manipulated (mean +/- SE: 33.8 +/- 1.3%), while in the hemodilution group, the Hct was reduced to 12.5 +/- 1.9% by exchange of blood with PoBH, before clipping the cerebral vessels. Staining with 2,3,5- triphenyltetrazolium chloride (TTC) was used to evaluate the infarct size. The infarct volume was 427 +/- 52 mm3 in the control animal, and 1026 +/- 311 mm3 (p < 0.01 when compared with the control group) in the animal hemodiluted with PoBH. PoBH hemodilution was found to be associated with vasoconstriction. This pathological vasoconstriction probably counteracted any beneficial effects from the lowered viscosity and explains our negative results. Vasoconstriction has to be overcome before hemodilution can have its beneficial effect in reducing the cerebral ischemia.
Chu
D
D
Department of Neurosurgery, Taipei Municipal Jen-Ai Hospital, Taiwan, ROC.
Ogilvy
C S
CS
D000818:Animals; D001809:Blood Viscosity; D002545:Brain Ischemia / Q000097:blood / Q000517:prevention & control*; D002417:Cattle; D002544:Cerebral Infarction / Q000473:pathology; D005340:Fibrinogen / Q000032:analysis; D006400:Hematocrit; D006438:Hemodilution / Q000379:methods*; D006454:Hemoglobins / Q000627:therapeutic use*; D011817:Rabbits
D006454:Hemoglobins; D005340:Fibrinogen