Intranasal nitroglycerin and intraocular pressure during general anesthesia

Abstract

Two separate studies of the effects of nitroglycerin (NTG) on intraocular pressure (IOP) were conducted. In study I, 12 healthy adults received 3 ml NTG solution (2 mg/3 ml) intranasally during steady-state anesthesia. This resulted in a significant decrease in IOP along with decreases in arterial blood pressure and central venous pressure. In study II, 30 patients, classified randomly into two equal groups, received either normal saline (3 ml) or NTG solution (2 mg/3 ml) intranasally, in a double-blind manner, 2 minutes before anesthetic induction with thiopental followed by succinylcholine (1.5 mg/kg). In patients given saline, IOP increased significantly above the preinduction levels after succinylcholine. Tracheal intubation increased it further. In the NTG group, increases in IOP after succinylcholine and after tracheal intubation were significantly less than in the control (saline) group. It is concluded that intranasal administration of NTG decreases IOP in anesthetized patients and, when employed as pretreatment, allows the use of succinylcholine to facilitate tracheal intubation without an increase in IOP above preinduction levels.