Efficacy of dexmedetomidine premedication on attenuation of intraocular pressure changes after succinylcholine and endotracheal intubation

Succinylcholine, is one of the most commonly used muscle relaxant for rapid sequence airway management. It increases the Intraocular pressure (IOP) which is deleterious in open globe injuries. We studied the effects of Inj. dexmedetomidine, a highly selective α2-adrenoceptor agonist, on IOP and hemodynamic responses to succinylcholine and tracheal intubation.

Sixty ASA I-II patients, scheduled for elective non-ophthalmic surgeries requiring general anesthesia were randomly premedicated by intravenous Inj. dexmedetomidine 0.4 μg/kg (Group-D) or saline (Group-S) (30 patients each group). Heart rate (HR), mean arterial pressure (MAP), and IOP (using Schiotz tonometer) were measured 10 minutes before and after the premedication, 30 seconds after succinylcholine and at 1, 5 and 10 minutes after intubation.

Ten minutes after Inj. dexmedetomidine administration, there was marked decrease in IOP. After intubation there was a rise in IOP, however it remained below baseline IOP (p=0.315) and remained low at 10th minute after intubation (p<0.001) which was statistically significant. In the control group, there was a significant rise in IOP following Inj. succinylcholine and intubation which remained above baseline IOP even at 10th minute after intubation. HR, Systolic and diastolic blood pressure, and MAP markedly increased at 1 minute following intubation in the control group whereas in dexmedetomidine group, they remained below baseline (p<0.001).

Intravenous dexmedetomidine at a dose of 0.4 μg/kg can be used for attenuation of rise in IOP associated with succinylcholine and tracheal intubation in patients with open globe injuries.