Effect of hematocrit variations on cerebral blood flow and basilar artery diameter in vivo

Jan Paul Muizelaar, G. J. Bouma, J. E. Levasseur, H. A. Kontos

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Despite observations that pial arterioles constrict with decreased blood viscosity or hemodilution, several investigators have found an inverse relationship between cerebral blood flow (CBF) and hematocrit (Hct) under physiological conditions. To investigate whether this is due to a dilation of the more proximal large cerebral arteries, in vivo responses of CBF and basilar artery to hemodilution and hemoconcentration were studied in 21 anesthetized normal cats, using a closed clival window model. An inverse correlation between Hct and CBF was found, but CBF responses were smaller than previously reported data suggest. Varying Hct between 60 and 120% of baseline caused CBF to vary between 140 and 90%, approximately. Moderate hemodilution was associated with a significant decrease (-4.4%) in basilar artery diameter (P < 0.05), but other Hct manipulations had no consistent effect on basilar artery diameter. It is concluded that dilation of large cerebral arteries cannot account for the decreased cerebrovascular resistance following hemodilution but that a disproportionate reduction of in vivo viscosity must be responsible. Pial arteriolar constriction after hemodilution therefore probably reflects a normal autoregulatory adjustment of vasomotor tone to altered blood rheology, whereas changes in large artery caliber may serve to modulate microvascular pressure.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume262
Issue number4 31-4
StatePublished - 1992
Externally publishedYes

Fingerprint

Cerebrovascular Circulation
Hemodilution
Basilar Artery
Hematocrit
Cerebral Arteries
Dilatation
Blood Viscosity
Rheology
Arterioles
Constriction
Viscosity
Cats
Arteries
Research Personnel
Pressure

Keywords

  • cat
  • cerebral circulation
  • vascular resistance
  • viscosity

ASJC Scopus subject areas

  • Physiology

Cite this

Effect of hematocrit variations on cerebral blood flow and basilar artery diameter in vivo. / Muizelaar, Jan Paul; Bouma, G. J.; Levasseur, J. E.; Kontos, H. A.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 262, No. 4 31-4, 1992.

Research output: Contribution to journalArticle

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