Effect of dexmedetomidine premedication on the intraocular pressure changes after succinylcholine and intubation

Background. Succinylcholine is still recommended for some situations in open globe injuries. However, the use of succinylcholine is associated with an increase in intraocular pressure (IOP). This may be deleterious in open globe injuries. No method has previously been shown to abolish completely this rise in the IOP. We investigated whether dexmedetomidine, an alpha-2 agonist, could attenuate this increase in the IOP after succinylcholine and intubation. Methods. Forty patients with no pre-existing eye disease undergoing general anaesthesia were randomly premedicated by i.v. dexmedetomidine 0.6 mu g kg(-1), or saline. Heart rate (HR), mean arterial pressure (MAP), and IOP (using Schioetz tonometer) were measured before, after the premedication, after thiopental, after succinylcholine, immediately after intubation, and then every 2 min for 6 min. Results. Succinylcholine and intubation increased IOP in both groups. However, in the dexmedetomidine group, the IOP rise was not different from the baseline value (P = 0.65) and was significantly lower than in the saline group (P = 0.003). After intubation, the MAP in the control group was higher than that in the dexmedetomidine group (P = 0.041) and exceeded the baseline value (P < 0.001). The HR also showed less fluctuation in the dexmedetomidine group than in the saline group. Conclusions. We conclude that dexmedetomidine could be a beneficial premedication in open globe injuries.