Physiologic effects from the introduction of blood and other substances into the subarachnoid space of dogs.

Abstract

S OLUTrONS of normal saline, injected under pressure into the subarachnoid space, escape into the orbital tissues, producing proptosis and subconjunctival edema, u When normal saline is injected at pressures in excess of 100 ram. Hg, drainage from the nostrils is often apparent . 11 Solutions of dextran, plasma protein and colloidal gold also pass readily from the subaraehnoid space, although more slowly than does normal saline. I f erythrocytes or carbon particles from India ink are injected within the subarachnoid space in advance of an injection of normal saline, the flow of saline out of the subarachnoid space is blocked, and hence the flow of saline into the subarachnoid space also is impeded. Openings tha t can be blocked by erythrocytes or carbon particles are present about the optic nerves 4 and about the olfactory nerves. 3 In addition, spaces tha t permit the passage of fluid and particles have been demonstrated about the spinal nerves, 12 and probably are present around other cranial nerves. The arachnoid villi, whose importance was emphasized by Weed, s,9 have been shown experimentally by Welch and Pollay TM to permit perfusion of liquids and particles into the venous system in the monkey. Arachnoid villi in other species probably function in the same way. Simmonds 7 recovered erythrocytes labeled with p32 in the systemic circulation after their injection into the subarachnoid space of rabbits. Adams and Prawirohardjo 1 recovered Cr zt labeled erythrocytes,