Sufentanil or clonidine for blunting the increase in intraocular pressure during rapid-sequence induction.

Background and objective: The aim was to determine if the intravenous administration of sufentanil or clonidine before the induction of anaesthesia could obtund the increase of intraocular pressure associated with rapid-sequence induction. Methods: Thirty-two ASA I-II patients with no history of eye illness scheduled for elective non-ophthalmic surgery were randomly assigned to receive either sufentanil 0.05 μg kg -1 i.v. (Group A, n = 15) or clonidine 2μg kg -1 i.v. (Group B, n = 17) prior to induction. General anaesthesia was induced with thiopental (5 mg kg -1 ) followed by succinylcholine 1 mg kg -1 to facilitate tracheal intubation. The general anaesthetic technique was standardized in both groups. Intraocular pressure was measured using the Schioetz tonometer just before the succinylcholine administration (t 0 ), just before tracheal intubation (t 1 ) and immediately after intubation (t 2 ). Mean arterial pressure and heart rate were recorded at the same time intervals. Results: Intraocular pressures were similar in both groups at t 0 , but the sufentanil group had significantly lower values compared with the clonidine group just before (t 1 ) and immediately after tracheal intubation (t 2 ). Conclusions: Sufentanil is effective in blunting the increase in intraocular pressure caused by rapid-sequence induction with succinylcholine, while clonidine did not seem to have any effect in intraocular pressures just before (t 1 ) and just after (t 2 ) intubation.