Effects of lidocaine, succinylcholine, and tracheal intubation on intraocular pressure in children anesthetized with halothane-nitrous oxide.

Both succinylcholine and tracheal intubation may increase intraocular pressure (IOP) in lightly anesthetized individuals (1,2). Controversy exists concerning the relative contributions of succinylcholine or intubation itself to the increase in IOP (2,3). Because increased IOP might further damage the eye with a perforating injury (1,3), several drugs to prevent or attenuate intraocular hypertension caused by succinylcholine and intubation have been evaluated, with mixed results. Lidocaine pretreatment has been utilized in at least four studies (3-6), with moderate success reported in one (6); most patients were adults and all were given thiopental for induction of anesthesia. To our knowledge, there has been no pediatric study specifically assessing the efficacy of lidocaine pretreatment in diminishing the increase in IOP associated in adults with succinylcholine and subsequent intubation. Furthermore, there has been no such study in patients undergoing an inhalation induction. We studied children in whom anesthesia was induced with halothane and nitrous oxide (N20). In addition to evaluating lidocaine pretreatment in preventing a succinylcholine-induced increase in IOP, we determined the effects of either lidocaine alone or succinylcholine alone on IOP and separately measured the additional effects of intubation on IOP. Preextubation measurements were also made.