Studies on Intracranial Pressure

Abstract

1. The results of this work form a confirmation of the earlier work of Cushing in all details investigated. 2. The increase of blood pressure that results from an increase of the intracranial pressure above the blood pressure is due in the dog to a vaso-constriction of the vessels of the intestine, the kidney and the limbs. Preceding this constriction there is dilatation. 3. The anastomotic connection between the internal carotid artery within the skull and the ophthalmic branch of the internal maxillary is of a size in the dog approximately equal to the internal carotid outside of the skull. The anatomical relations are such as to indicate that the internal maxillary artery in this animal is a cerebral artery equal in importance to the internal carotid. The anastomotic connection because of its position within the cranial cavity is unaffected except by extreme grades of intracranial compression. 4. The ordinary method of artificial perfusion of the dog's brain as used in physiological investigation appears from this work to be of no value, since there is at least one important path open besides that through the vessels of the brain. 5. The increase of the intracranial pressure above the blood pressure leads to a complete anæmia, superficial and deep, of the blood vessels of the brain. If the intracranial pressure is not greatly increased above the blood pressure, the circle of Willis and some of the larger arterial connections at the base of the brain are more or less well injected. An intracranial pressure somewhat below blood pressure leads apparently to a certain degree of anæmia directly beneath the point of entrance of the intracranial fluid; the condition of the rest of the brain as regards blood supply is normal.

Vascular responses to acute intracranial hypertension

“…Similar views have been expressed by Janeway (1904), Eyster, Burrows, and Essick (1909), Howe (1927), Munro (1927) and others. The level of CSFP which stimulates a rise of the BP has been described variously by the different authors.…”

“…The level of CSFP which stimulates a rise of the BP has been described variously by the different authors. The BP may be affected when the CSFP reaches the level of (a) the diastolic BP (Cannon, 1901;Eyster, 1906;Eyster et al, 1909;Howe, 1927;Munro, 1927;Weed, 1929;Wolff and Forbes, 1929;Wilson, 1932;Fremont-Smith and Merritt, 1933;Masserman, 1934; and others), (b) the systolic BP (Cushing, 1901;Wright, 1938;Weinstein, Langfitt, and Kassell, 1964; and others), or (c) the mean BP (Eyster et al, 1909;Howe, 1927;Munro, 1927;Browder and Meyers, 1938; and others). On raising the CSFP to about 40 mm Hg experimentally, no response in the BP was detected by Weed and Flexner (1933), Bedford (1942), and Hedges (1963).…”

“…Primary vasoconstriction ofneurogenic origin from the medullary centres (Cushing, 1901;Eyster et al, 1909;Grimson, Wilson, and Phemister, 1937;Forster, 1943;Brown, 1956;Langfitt, Weinstein, and Kassell, 1965;and others), and probably from the midbrain (Langfitt, Kassell, and Weinstein, 1965) 596 Vascular responses to acute intracranial hypertension which, in turn, is due to local ischaemia. Anrep and Starling (1925) and Tsubura (1924) considered the stimulating factors to be the anoxia and fall in the BP of the medullary centres.…”

Surgical Reduction of Tumour Bulk in Management of Abdominal Burkitt's Lymphoma

“…pressure and mean systemic arterial pressure in patients with cerebral tumours (Kety et al, 1948). Raised intracranial pressure can produce disturbances in vasomotor and respiratory function due to ischaemia of the medullary centres (Cushing, 1902;Eyster et al, 1909) with stimulaition of the sympathoadrenal pathway. The resulting hypertension, due 'to catecholamine and perhaps renin release, can be blocked in dogs by spinal cord section or autonomic ganglion blockade by tetraethylammonium chloride (Dickinson and McCubbin, 1963).…”

Noninvasive assessment of intracranial pressure using subharmonic-aided pressure estimation: An experimental study in canines

“…When the ICP is continuously increased, the average arterial pressure will increase reactively, and relatively stable intracranial perfusion will be maintained. However, the reactive changes in arterial pressure lag behind these changes, and the increasing trend decreased with increasing ICP 24 …”