Effects of Different Doses of Dexmedetomidine on Intraocular Pressure after Suxamethonium in Non-ocular Surgeries: A Randomised Controlled Trial

Abstract

Introduction: Succinylcholine causes a rise in Intraocular Pressure (IOP) and is deleterious in patients with open globe injuries. Dexmedetomidine, by its virtue of central sympatholytic action can help prevent this rise in IOP. Aim: To find out the optimal dose of Dexmedetomidine in preventing the rise of IOP after administration of Suxamethonium. Materials and Methods: One hundred American Society of Anesthesiologists (ASA) I or II patients posted for non-ophthalmic surgery were included in this randomised, prospective, double blind study. Patients were randomly allocated to four groups. Group A (n=25) received Dexmedetomidine 0.6 μg/kg, Group B (n=25) received Dexmedetomidine 0.8 μg/kg, Group C (n=25) received Dexmedetomidine 1 μg/kg, Group D (n=25) received Normal Saline (NS) over a period of 10 minutes and IOP was measured at different points in time. Results: Premedication with Dexmedetomidine at doses of 0.6 μg/kg, 0.8 μg/kg and 1 μg/kg intravenous (IV) were equally effective in attenuation of the rise in IOP associated with Succinylcholine administration. The IOP recorded was 15.53±1.10 mm of Hg in Group A, 14.49±0.94 mm of Hg in Group B, 14.72±1.03 mm of Hg in Group C as compared to 20.12±1.40 mm of Hg in the control group (Group D) after 60 seconds of injecting Suxamethonium. It also significantly obtunded the sympathetic response to laryngoscopy and intubation. However, the incidence of side effects increased with incremental doses. Conclusion: Dexmedetomidine 0.6 μg/kg IV premedication is the optimum dose to be used for attenuating the rise in IOP associated with Succinylcholine administration in situations where rise of IOP may be detrimental.