Critical Thresholds of ICP and Cerebral Perfusion Pressure (CPP) for Cerebral Blood Flow and Brain Functions — Noninvasive Study

1989 ◽  
pp. 858-863 ◽  
Author(s):  
M. Shigemori ◽  
T. Moriyama ◽  
H. Nakashima ◽  
T. Tokutomi ◽  
N. Nishio ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Critical Thresholds ◽  
Brain Functions

Effects of graded hypotension on cerebral blood flow, blood volume, and mean transit time in dogs

1992 ◽  
Vol 262 (6) ◽  
pp. H1908-H1914 ◽  
Author(s):  
M. Ferrari ◽  
D. A. Wilson ◽  
D. F. Hanley ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Blood Volume ◽  
Transit Time ◽  
Cerebral Perfusion ◽  
Pressure Range ◽  
Cerebral Blood Volume ◽  
Perfusion Pressure ◽  
Mean Transit Time

This study tested the hypothesis that cerebral blood flow (CBF) is maintained by vasodilation, which manifests itself as a progressive increase in mean transit time (MTT) and cerebral blood volume (CBV) when cerebral perfusion pressure is reduced. Cerebral perfusion pressure was decreased in 10 pentobarbital-anesthetized dogs by controlled hemorrhage. Microsphere-determined CBF was autoregulated in all tested cerebral regions over the 40- to 130-mmHg cerebral perfusion pressure range but decreased by 50% at approximately 30 mmHg. MTT and CBV progressively and proportionately increased in the right parietal cerebral cortex over the 40- to 130-mmHg cerebral perfusion pressure range. Total hemoglobin content (Hb1), measured in the same area by an optical method, increased in parallel with the increases in CBV computed as the (CBF.MTT) product. At 30 mmHg cerebral perfusion pressure, CBV and Hb were still increased and MTT was disproportionately lengthened (690% of control). We conclude that within the autoregulatory range, CBF constancy is maintained by both increased CBV and MTT. Outside the autoregulatory range, substantial prolongation of the MTT occurs. When CBV is maximal, further reductions in cerebral perfusion pressure produce disproportionate increases in MTT that signal the loss of cerebral vascular dilatory hemodynamic reserve.

CONTINUOUS COMPUTERIZED TRACKING DEFINES RELATIONSHIP BETWEEN CEREBRAL BLOOD FLOW, CEREBRAL PERFUSION PRESSURE AND TIME

1995 ◽  
Vol 23 (Supplement) ◽  
pp. A79
Author(s):  
George Chovanes ◽  
Michael Pasquale ◽  
Mark Cipolle ◽  
Rafael Richards ◽  
Michael Rhodes
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Cerebral Perfusion ◽  
Perfusion Pressure

CEREBRAL BLOOD FLOW IN TRAUMATIC CONTUSIONS IS PREDOMINANTLY REDUCEDAFTER AN INDUCED ACUTE ELEVATION OF CEREBRAL PERFUSION PRESSURE

Neurosurgery ◽  
2007 ◽  
Vol 60 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Arturo Chieregato ◽  
Alessandra Tanfani ◽  
Christian Compagnone ◽  
Rosario Pascarella ◽  
Luigi Targa ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Perfusion Pressure ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Acute Elevation

scholarly journals Carbon Dioxide Induced Changes in Cerebral Blood Flow and Flow Velocity: Role of Cerebrovascular Resistance and Effective Cerebral Perfusion Pressure

2015 ◽  
Vol 35 (9) ◽  
pp. 1470-1477 ◽  
Author(s):  
Frank Grüne ◽  
Stephan Kazmaier ◽  
Robert J Stolker ◽  
Gerhard H Visser ◽  
Andreas Weyland
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Cerebral Perfusion Pressure ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Cerebrovascular Resistance ◽  
Flow Pressure ◽  
Induced Changes ◽  
Zero Flow

In addition to cerebrovascular resistance (CVR) zero flow pressure (ZFP), effective cerebral perfusion pressure (CPPe) and the resistance area product (RAP) are supplemental determinants of cerebral blood flow (CBF). Until now, the interrelationship of PaCO2 -induced changes in CBF, CVR, CPPe, ZFP, and RAP is not fully understood. In a controlled crossover trial, we investigated 10 anesthetized patients aiming at PaCO2 levels of 30, 37, 43, and 50 mm Hg. Cerebral blood flow was measured with a modified Kety-Schmidt-technique. Zero flow pressure and RAP was estimated by linear regression analysis of pressure–flow velocity relationships of the middle cerebral artery. Effective cerebral perfusion pressure was calculated as the difference between mean arterial pressure and ZFP, CVR as the ratio CPPe/CBF. Statistical analysis was performed by one-way RM-ANOVA. When comparing hypocapnia with hypercapnia, CBF showed a significant exponential reduction by 55% and mean VMCA by 41%. Effective cerebral perfusion pressure linearly decreased by 17% while ZFP increased from 14 to 29 mm Hg. Cerebrovascular resistance increased by 96% and RAP by 39%; despite these concordant changes in mean CVR and Doppler-derived RAP correlation between these variables was weak ( r = 0.43). In conclusion, under general anesthesia hypocapnia-induced reduction in CBF is caused by both an increase in CVR and a decrease in CPPe, as a consequence of an increase in ZFP.

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