Drugs and cerebral autoregulation

Dg, McDowall

doi:10.1111/j.1365-2362.1982.tb00682.x

Cited by 10 publications

(6 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It is possible that, with focal ischaemia (present study) rather than global ischaemia, catecholaminemediated vasoconstriction may result in shunting (a "Robin Hood steal") of blood away from nonischaemic regions to the jeopardized areas (in which there is vasoparalysis). Both isoflurane and sodium nitroprusside are known cerebral vasodilators [16][17][18][19] and it follows that, in the presence of focal ischaemia, vasodilatation of normal vessels may result in the opposite phenomenon, with shunting ("steal") of blood away from ischaemic brain to adjacent normal tissue.…”

Section: Discussionmentioning

confidence: 99%

Influence of Hypotension and Hypotensive Technique on the Area of Profound Reduction in Cerebral Blood Flow During Focal Cerebral Ischaemia in the Rat

Cole

Drummond

Shapiro

et al. 1990

British Journal of Anaesthesia

View full text Add to dashboard Cite

We have studied the effect of induced hypotension on reduction in regional cerebral blood flow (CBF) during middle cerebral artery occlusion (MCAO). Rats were anaesthetized with 2% isoflurane. MCAO was performed during four conditions: normotension (mean arterial pressure (MAP) 107 (SD 15) mm Hg); hypovolaemic hypotension (blood withdrawn to reduce MAP to 43 (2) mm Hg); nitroprusside (SNP) hypotension (MAP reduced to 45 (3) mm Hg); isoflurane hypotension (MAP reduced to 44 (3) mm Hg with 3.5 (0.48)% isoflurane). Hypotension was established before MCAO and was maintained for 10 min, at which time the dimension of the brain areas with zero CBF was determined autoradiographically. All hypotensive regimens were associated with significantly larger areas of extreme CBF reduction. In a coronal section at the centre of the MCA distribution, the area with zero CBF (expressed as a percentage of the area of the entire coronal section) was: normotension 4.7 (4.5)%; hypovolaemic hypotension 10.1 (2.8)%; nitroprusside hypotension 13.5 (2.0)%; and isoflurane hypotension 11.8 (3.9)%. There were no differences between the three hypotensive regimens. The data indicate that, when focal cerebral ischaemia occurs during hypotension (MAP 45 mm Hg) induced by any of the three regimens evaluated, extreme CBF reduction occurs over larger areas than are observed during normotension. These data confirm the importance of arterial pressure as a determinant of collateral flow during focal cerebral ischaemia.

show abstract

Section: Discussionmentioning

confidence: 99%

Influence of Hypotension and Hypotensive Technique on the Area of Profound Reduction in Cerebral Blood Flow During Focal Cerebral Ischaemia in the Rat

Cole

Drummond

Shapiro

et al. 1990

British Journal of Anaesthesia

View full text Add to dashboard Cite

show abstract

“…The effects of anes thetics on cerebral hemodynamics and me tabolism are well known in humans as well as in animals [16], Among the various anes thetics, halothane, depending on the depth of anesthesia, only interferes with CBF autoreg ulation. On the other hand, barbiturates, which reduce cerebral metabolism, and have a protective action in cerebral ischemia, usually maintain a normal CBF autoregula tion [19].…”

Section: Discussionmentioning

confidence: 99%

Autoregulation of Cerebral Blood Flow in Young and Aged Spontaneously Hypertensive Rats (SHR)

Fujishima¹,

Sadoshima²,

Ogata³

et al. 1984

Gerontology

View full text Add to dashboard Cite

Autoregulation of cerebral blood flow (CBF) to the controlled hemorrhagic hypotension was studied in young adult spontaneously hypertensive rats (SHR, 3.4 months of age) and aged SHR (20.3 months). There were no differences in average values for mean arterial pressure and baseline CBF between two groups of rats. During hypotension, however, CBF was more reduced in aged SHR than in young SHR, indicating that the lower limit of cerebral autoregulation is shifted to a higher level in aged SHR. Such upward shift of the autoregulation is likely due to a long-lasting hypertension which may lead to the diminished vasodilatory response of the brain to hypotension.

show abstract

“…to improve autoregulation, this terminology should not be used to describe the effects of the vasodilators. 37 Hence, if blood pressure is first lowered with e.g. dihydralazine and global CBF maintained normal below the lower limit of autoregulation in a hypertensive rat, and then blood pressure is raised with angiotensin infusion, gross cerebral hyperemia will result as autoregulation is evidently lost.…”

mentioning

confidence: 99%