The effects of atracurium on intraocular pressure during steady state anaesthesia and rapid sequence induction: a comparison with succinylcholine

The effects of atracurium 0.5 mg X kg-1 or succinylcholine 1.0 mg X kg-1 on intraocular pressure (IOP) were studied in ten patients during steady state nitrous oxide-oxygen-fentanyl anaesthesia. IOP was unchanged following atracurium but, one minute after succinylcholine, it had increased significantly (p less than 0.025) from 5.6 mmHg to 13.2 mmHg and remained significantly above control for 3 min. Twenty additional patients received either atracurium 0.75 mg X kg-1 or succinylcholine 1.0 mg X kg-1 as part of a rapid sequence induction, atracurium being administered prior to, and succinylcholine after, thiopentone. Intubating conditions were acceptable in all patients in both groups. Administration of thiopentone was associated with a significant (p less than 0.025) decrease in IOP. Although IOP increased in both groups as a result of laryngoscopy and intubation (from 8.0 mmHg to 12.1 mmHg in the atracurium Group and from 7.5 mmHg to 14.5 mmHg in the succinylcholine group) it did not exceed pre-induction IOP in the former. In the succinylcholine group, IOP after intubation exceeded pre-induction values for 2 min, although this increase was significant (p less than 0.05) only at the immediate post-intubation reading. It is concluded that atracurium in a dose of 0.75 mg X kg-1 is a suitable relaxant for use in rapid sequence induction.