Stable xenon does not increase intracranial pressure in primates with freeze-injury-induced intracranial hypertension.
Stable xenon (Xe)-enhanced computed tomography is a potentially valuable tool for high resolution, three-dimensional measurement of CBF in patients. However, reports that Xe causes cerebrovascular dilation and increases intracranial pressure (ICP) have tempered enthusiasm for its use. The effects of 5 min of 33% Xe inhalation on ICP (right and left hemispheres) were studied in eight fentanyl-anesthetized Rhesus monkeys after right-sided cortical freeze injury. ICP, CBF, and physiological variables were monitored for up to 6 h postinsult. The preinjury (control) right hemispheric ICP was 8 +/- 5 mm Hg (mean +/- SD) and left hemispheric ICP was 5 +/- 2 mm Hg. Postinjury observations were classified into low (less than 15 mm Hg) and high ICP (greater than or equal to 15 mm Hg) groups. Both right and left ICP values averaged 9 +/- 3 mm Hg in the low ICP group. In the high ICP group, the right ICP was 20 +/- 4 mm Hg and left ICP was 21 +/- 6 mm Hg. ICP was unchanged by Xe inhalation under control conditions as well as in both low and high ICP groups postinjury. Postinjury, the MABP decreased 10-15 mm Hg in the low ICP group and 10-17 mm Hg in the high ICP group 2-3 min after the start of Xe inhalation (p less than 0.05). These results show that 33% Xe inhalation does not increase ICP in fentanyl-anesthetized monkeys but could decrease MABP in stressed states, presumably because of the anesthetic effects of Xe.
Darby
J M
JM
Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh School of Medicine, Pennsylvania.
Nemoto
E M
EM
Yonas
H
H
Melick
J
J
D000758:Anesthesia; D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects; D005260:Female; D005283:Fentanyl; D005615:Freezing; D007427:Intracranial Pressure / Q000187:drug effects*; D008253:Macaca mulatta; D008297:Male; D011559:Pseudotumor Cerebri / Q000209:etiology / Q000503:physiopathology*; D014978:Xenon / Q000494:pharmacology*
D014978:Xenon; D005283:Fentanyl