Changes in Intracranial Pressure and Compliance during Adenosine Triphosphate-induced Hypotension in Dogs

Abstract

Intracranial pressure (ICP) was measured during induced hypotension with increasing doses of adenosine triphosphate (1-5 mg X kg-1 X min-1 ATP) in dogs without (group I) and with (group II) intracranial hypertension. After administration of 1 mg X kg-1 X min-1 ATP, ICP increased significantly from 11 +/- 4 mm Hg to 14 +/- 5 mm Hg (mean +/- SEM) (P less than 0.05; group I) and from 27 +/- 2 mm Hg to 38 +/- 6 mm Hg (P less than 0.05; group II), while mean arterial pressure (MAP) decreased from 103 +/- 10 mm Hg to 86 +/- 6 mm Hg (P less than 0.05; group I) and from 110 +/- 11 mm Hg to 90 +/- 11 mm Hg (P less than 0.05; group II). In both groups a slow decrease of ICP after the initial increase occurred with further lowering of MAP, but ICP remained significantly above control values even with a dose of 5 mg X kg-1 X min-1 ATP (P less than 0.05). Ventricular volume-pressure response curves (VPR) before and during intravenous infusion of 3 mg X kg-1 X min-1 ATP were constructed to determine changes in intracranial compliance (ICC). In both groups I and II ATP decreased ICC. On the basis of these results it is recommended that in the presence of intracranial mass lesions ATP should not be given to induce arterial hypotension before the dura is opened.