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

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.

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 microg kg(-1) i.v. (Group A, n = 15) or clonidine 2 microg 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 (t0), just before tracheal intubation (t1) and immediately after intubation (t2). Mean arterial pressure and heart rate were recorded at the same time intervals.

Intraocular pressures were similar in both groups at t0, but the sufentanil group had significantly lower values compared with the clonidine group just before (t1) and immediately after tracheal intubation (t2).

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 (t1) and just after (t2) intubation.