Comparative anesthetic effects on aqueous humor dynamics in the cynomolgus monkey

Cynomolgus monkeys were anesthetized with either intravenous (IV) ketamine hydrochloride, IV ketamine and intramuscular (IM) diazepam, IM methohexital sodium and IM pentobarbital sodium, or endotracheal halothane. Intraocular pressure, aqueous humor flow rate (F), anterior chamber volume, corneal endothelial transfer coefficient (Ka), and anterior chamber elimination coefficient (Ke) were determined noninvasively, using applanation tonometry, keratometry, pachymetry, and fluorophotometry. Arterial blood gases (ABG), acid-base balance, and mean arterial pressure (MAP) were monitored. The IOP was highest with ketamine and lowest with pentobarbital. The F and Ke were about 30% lower with halothane than with the other regimens, while Ka was highest with ketamine. The ABG and MAP were within normal physiologic limits with the three noninhalation regimens; pH was within normal limits with all four regimens. The MAP was lowest and PO2 highest with halothane, while pH was highest with pentobarbital.