Cerebrospinal Pressure,Hydrocephalus and Blood Pressure in the Cat Following Intracisternal Injection of Colloidal Kaolin

Abstract

Certain animals develop an increased intracranial pressure associated with vascular hypertension following the intracisternal injection of colloidal kaolin. This syndrome was first described in the dog by Heller 1 and his associates, and recently confirmed by Jeffers, Lindauer and Lukens. 2 A similar response in the white rat has been described by Griffith, Jeffers, and Lindauer, 3 , 4 and Griffith and Roberts. 5 They found that the cerebrospinal pressure, normally less that 100 mm of water, was increased to about 260 mm, while the blood pressure, normally below 140 mm of mercury, ranged between 150 and 300 mm. At necropsy internal hydrocephalus was found in rats that had survived a month or more. The present report deals with similar studies in cats.

The method for measuring blood pressure was that described by Griffith and Collins 6 for man and by Griffith 7 for the rat. It consists in encircling the upper part of a limb with a blood pressure cuff constructed of appropriate size, while blood flow is observed through the microscope in a more distal cutaneous area of this same limb. This area usually has to be prepared in advance by shaving. When the pressure in the cuff exceeds systolic pressure the flow in the capillaries stops, to start again when the pressure in the cuff is lowered below systolic pressure. Thus systolic pressure alone is measured.

Blood pressure measurements were made on about 24 normal cats. Ether anesthesia was used throughout. Cisternal puncture was successfully performed on 15 cats. In approximately half of these the pressure of cerebrospinal fluid was measured directly by permitting the fluid to pass into a graduated capillary tube, so narrow that the loss of fluid was only 0.2 cc per 100 mm rise. Then 0.5 cc of cerebrospinal fluid was withdrawn, and a kaolin suspension slightly less in volume was injected. The kaolin suspension consisted of 25% by volume of kaolin boiled up in distilled water and permitted to cool before injecting.