Changes in canine intracranial pressure in response to infusions of sodium nitroprusside and trinitroglycerin
Morris, P.J.; Todd, M.; Philbin, D.
British Journal of Anaesthesia 54(9): 991-995
1982
ISSN/ISBN: 0007-0912 PMID: 6810909 Document Number: 186573
Intracranial pressure (ICP) was measured in 11 normocapnic dogs anesthetized with thiopentone and morphine and ventilated with O2-enriched air. The changes in ICP in response to infusions of either sodium nitroprusside (SNP) 10 .mu.g/kg per min (5 animals) or glyceryl trinitrate (TNG) 30 .mu.g/kg per min (6 animals) i.v. were recorded at a normal baseline ICP and, in the same animals, once the baseline ICP had been increased to 20 and 40 mm Hg. Modest decreases (10-20%) in mean arterial pressure (MAP) were noted during the infusions and the concomitant increases in ICP in every animal were significant at each value of ICP (P < 0.05). Acute pupillary dilatation was noted during SNP infusion, and further observations of pupillary changes occurring during infusion of both SNP and TNG at greater ICP (60 mm Hg) emphasize the existence of transtentorial pressure gradients and their aggravation by the use of these agents in the presence of a very high ICP.