J.Jpn. Surg. Soc.. 61(3): 387-408, 1960

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THE IMPORTANCE OF ESTIMATION FOR REGIONAL CEREBRAL BLOOD FLOW (EXPERIMENTAL OBSERVATION CONCERNING THE HEMODYNAMICS OF THE GREAT VEIN OF GALEN)

Very little is known about different responses in the regional cerebral blood flow at the several portions of the brain. In the present work, blood flow change was continuously recorded in the vein of Galen comparing with in those of the superior sagittal sinus, by means of our modified drip method of Ingvar's (1956), which originally applied quantitatively for the brain blood flow studies. On the contrary to the great vein of Galen being supposed to collect the circulating blood of the brain stem, the superior sagittal sinus collect the circulating blood of the cerebral cortex, particularly a portion of the frontal and parietal lobes. The purpose of the present investigation was to determine the responses in the cerebral blood flow (CBF) of the brain stem and cerebral cortex simultanously under the several conditions such as hemorrhagic shock, induced hypotension or hypertension, asphyxia and administration of some drugs.
Experimental results were as follows:
1) Hemorrhagic shock
The cource throughout the hemorrhagic shock divided into the following four phases from the standpoint of CBF.
1st Phase : There was a slow decline in both CBF in the vein of Galen and of the superior sagittal sinus, which were parallel to the blood pressure falling until when it fell below 75 mmHg.
2nd Phase (compensatory phase) : In spite of the arterial pressure remained at the level of 60 mmHg, there was a marked increase in CBF, particularly in the vein of Galen which re-increased until it almost reached to the control level in the maximal value. Thereafter, CBF in the vein of Galen reduced rapidly, even though there was little change in blood pressure level.
3rd Phase: There was a slight transient increase in CBF, particularly in the superior sagittal sinus, which associated with the slight elevation of blood pressure.
4th Phase : CBF declined rapidly with a simultanous fall in the blood pressure, and then the CBF of the vein of Galen fall down to zero earlier than those of the superior sagittal sinus did.
These results suggested that there was an active decrease in cerebral vascular resistance in the 2nd Phase, particularly in the brain stem under low arterial pressure.
These mechanism of increasing blood flow were considerd to be partly due to the mechanical effect by the elevated blood pressure in the 3rd Phase, and partly due to the reflex vasomotor mechanism in the 2nd Phase.
2) Histamine or Acetylcholine shock
In the initial stage, CBF particularly in the vein of Galen rapidly reduced which was associated with the rapid fall of blood pressure. Thereafter, however, CBF increased more than the control level after returning to the control IeveI within a few minutes, and then CBF increment in the vein of Galen was much more than those in the superior sagittal sinus, even though the blood pressure remained at the lower level.
On the other hand, in the case of death due to the irrevereible shock, there was no response to increase in the 2nd stage. At that time CBF in the vein of Galen became to zero earlier than those in the superior asgittal sinus .
3) Induced hypotension by Hexamethonium Bromide
A reduce occurred in cerebral vascular resistance in spite of the falling blood pressure, as a result of which blood flow only slightly reduced, particularly in the vein of Galen. These results suggested that blood flow in the brain stem was maintained relatively constant, and it is of immediate interest in view of the use of induced hypotension in clinical practice.
4) Chlorpromazine
A fall occurred in cerebral vascular resistance, as a result of which blood flow was maintained relatively constant, even though the blood pressure was going to fall on. These findings also suggested the safety of the induced hibernation in clinical practice.
5) Banthine
Infusion of Banthine produced an initial decrease in CBF, followed by a slow return to control level, and then the blood flow in the vein of Galen was less than those of the superior sagittal sinus.
6) Noradrenaline, Neosynephrine
Infusion of Noradrenaline or Neosyphrine produced an initial rapid elevation of blood pressure, and then the blood flow increase in the vein of Galen was as much as in the superior sagittal sinus. These result were considered to be due to the mechanical effect by the raised systemic blood pressure, since there was an increase in cerebral blood flow despite the raised vascular resistance. Thereafter, however, the rise occurred in cerebral vascular resistance, as a results of which the blood flow decreased particularly in the vein of Galen.
7) Théraptique
A rapid rise occurred in blood pressure, as a result of which CBF rapidly increased, associated with a trasient hyperventilation, and then the CBF in the vein of Galen was much more than those in the superior sagittal sinus .
8) Asphyxia
In the acute asphyxia, on increase in CBF occurred in the initial stage, particularly in the vein of Galen, followed by a rapid decreased to zero in a fatal case. And then CBF in the vein of Galen was less than those in the superior sagittal sinus.
In the chronic asphyxia, a slight rise occurred in blood pressure, as a result of which the CBF slightly increased, particularly in the vein of Galen, and remained relatively constant throughout the course. The CBF increase in the brain stem suggested that a compensatory response worked to transport oxygen to the brain stem as much as possible in the initial stage.
9) Action of Nicotinic acid of Papaverine HCl on CBF
Intravenous administration of nicotinic acid induced an initial decrease in CBF, particularly in the vein of Galen, and was followed by the continuous marked increase, particularly in those of superior sagittal sinus.
Papaverine HCl given intravenously or intracarotidly rapidly induced a transient increase in CBF, particularly in the vein of Galen, associated with a marked decrease in cerebral vascular resistance, even though arterial pressure fell to 30 mmHg.
These evidence suggested that there was a considerable qualitative difference between nicotinic acid and papaverine HCl in the mode of response to cerebral vasculature, though these drugs likely let CBF increase.
(Author's abstract)

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