Trabecular outflow facility and formation rate of aqueous humor during anesthesia with sevoflurane-nitrous oxide or sevoflurane-remifentanil in rabbits.
In the present study, we examined the effect of sevoflurane and remifentanil on intraocular pressure (IOP) and fluid dynamics. Twenty-eight rabbits were anesthetized with halothane, and IOP was measured via a 25-gauge needle in the anterior chamber. Rabbits were then assigned to one of four groups, and halothane was replaced with sevoflurane 1% (n = 7), 2% (n = 7), 3% (n = 7), or 1% + remifentanil 0.65 microg kg(-1) x min(-1) i.v. (n = 7). In all groups, a series of intraocular infusions was made into the anterior chamber, and IOP, trabecular outflow facility, the rate of aqueous humor formation, and intraocular compliance were determined. With sevoflurane only, intraocular compliance decreased (55 +/- 14, 39 +/- 22, 31 +/- 17 nL/mm Hg; P < 0.05) as the concentration of sevoflurane increased. With sevoflurane 1% + remifentanil, intraocular compliance was significantly increased (100.1 +/- 30.5 nL/mm Hg; P < 0.05) compared with sevoflurane 1%, 2%, or 3%. Trabecular outflow facility, rate of aqueous humor formation, and IOP did not differ among groups, and IOP was similar to values obtained during halothane anesthesia.


CONCLUSIONS
The dose-related effects of sevoflurane on intraocular compliance did not produce significant intraocular pressure differences. Adding remifentanil to sevoflurane increased intraocular compliance. Sevoflurane or sevoflurane + remifentanil causes a decrease in intraocular pressure compared with the average of previously reported values in awake rabbits, and the magnitude of the decrease is similar to that previously reported in rabbits anesthetized with ethyl urethane, pentobarbital, or halothane alone or in combination with propofol, cocaine, or lidocaine.
Artru
A A
AA
Department of Anesthesiology, University of Washington School of Medicine, Seattle 98195-6540, USA. artruaa@u.washington.edu
Momota
Y
Y
D000758:Anesthesia; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006221:Halothane; D007429:Intraocular Pressure / Q000187:drug effects; D008738:Methyl Ethers; D009609:Nitrous Oxide; D010880:Piperidines; D011817:Rabbits; D000077208:Remifentanil; D000077149:Sevoflurane; D014129:Trabecular Meshwork / Q000187:drug effects* / Q000502:physiology
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D009609:Nitrous Oxide; D000077208:Remifentanil; D006221:Halothane