Rate of anterior chamber aqueous formation, trabecular outflow facility, and intraocular compliance during desflurane or halothane anesthesia in dogs

Abstract

The present study examined the effects of desflurane on intraocular pressure (IOP), the rate of anterior chamber aqueous formation, trabecular outflow facility, and intraocular compliance. The effects of desflurane were compared to those of halothane because the effects of halothane on intraocular fluid dynamics are well known. Twenty-two dogs were anesthetized for surgical preparation. Pancuronium was given intravenously to produce neuromuscular blockade, and the lungs were mechanically ventilated through a tracheal tube. After surgical preparation, anesthesia was maintained in Group 1 (n = 12) with halothane (0.8% expired) and in Group 2 (n = 10) with desflurane (7.0% expired). In both groups a series of intraocular infusions was made via a 30-gauge needle in the anterior chamber and IOP, aqueous formation, outflow facility, and intraocular compliance were determined. In Group 1 (halothane) IOP was 9.4 +/- 2.8 mm Hg (mean +/- SD), aqueous formation was 1.45 +/- 0.45 microL/min, outflow facility was 0.091 +/- 0.054 microL.min-1.mm Hg-1, and compliance was 377 +/- 282 nL/mm Hg. In Group 2 (desflurane) IOP was 11.3 +/- 3.8 mm Hg, aqueous formation was 1.61 +/- 0.56 microL/min, outflow facility was 0.097 +/- 0.062 microL.min-1.mm Hg-1, and compliance was 432 +/- 238 nL/mm Hg. These values did not differ between groups. It is concluded that in dogs aqueous humor dynamics during desflurane anesthesia are similar to those during halothane anesthesia.