Background and objective: The aim was to examine the course of intraocular pressure after relaxation with different doses of cisatracurium.
Methods: The investigation was carried out as a prospective, randomized double-blind study in a crossover design in 30 postoperative patients with stable haemodynamic and respiratory function (ASA I and II). To exclude any disrupting factors, patients remained intubated and continuously sedated. Twenty patients received an intubation dose (2 x ED95) of cisatracurium (0.1 mg kg(-1)) compared with atracurium (0.5 mg kg(-1)). In a second series, 10 patients were given an effective dose, ED95 (0.05 mg kg(-1)), and a repeat dose (0.02 mg kg(-1)) of cisatracurium. The intraocular pressure was determined before (T0) as well as 1 (T1), 5 (T5), 10 (T10), 15 (T15), 20 (T20) and 45 (T45) min after bolus administration.
Results: Intraocular pressure decreased after an intubation dose of either cisatracurium or atracurium, and reached a minimum after 10 min (6.7 +/- 2.2 and 7.9 +/- 2.1 mmHg, respectively). There was no significant difference between either muscle relaxant (P = 0.27). When lower doses of cisatracurium (0.05 and 0.02 mg kg(-1)) were applied, the intraocular pressure also decreased, albeit to a lesser extent and with a delayed onset (8.4 +/- 1.9 mmHg after 10 min, 9.9 +/- 3.4 mmHg after 15 min). There was no significant difference between dosages (p = 0.44).
Conclusions: Cisatracurium is a useful drug in patients when a decrease of intraocular pressure is wanted and where muscle relaxation is necessary and acceptable.