MANY of the effects of subarachnoid blood deposits are well documented. These include meningeal irritation,1-3 vasospasm,4,5 an obstruction to the free flow of cerebrospinal fluid (CSF).6-10 In previous studies sustained CSF pressure elevations were measured from the surface of the brain after subarachnoid blood injections.11,12 This work is extended here, and attempts are made to characterize a type of intracranial hypertension and to identify the mechanism. Two groups of experiments are presented: (1) analyses of CSF pressure rises after intracisternal infusions of blood fractions and inert particles and (2) assessments of subarachnoid blockade and other effects.
Method
Animal Preparation.
—The CSF pressures were recorded from the surface of the brain over prolonged periods. For this, adult mongrel dogs (6-15 kg [13.2-33 lb]) were anesthetized with sodium pentobarbital and paralyzed with gallamine triethiodide. The initial doses were 30 and 2 mg/kg; the maintenance dosages were 5