Background and Goal of Study: We studied the effects of dexmedetomidine, a new α- agonist, on intra-ocular pressure (IOP), haemodynamic parameters, sedation and anxiolysis in day-case cataract surgery under periocular anaesthesia.
Materials and Method: After ethic committee's approval and informed consent, 44 ASA physical status I-III patients scheduled for elective day-case cataract surgery were randomly assigned into two equal group (n = 22). In group I, sedation induction was done with dexmedetomidine 1 μg/kg/h. iv (infused in 10mins) and infusion was started as 0.2 μg/kg/h, whereas in group II, placebo group, was done an equal dose of saline. Infusion rates were adjusted according to sedation scale in group I.
Intraoperative heart rate (HR), systolic (SBP) diastolic (DBP) and mean (MBP) blood pressure, peripheric oxygen saturation (SpO2), visual rating scale (VAS) and sedation scale (Ramsay sedation scale) were recorded every 5 min before and during surgery and at 15 min intervals thereafter. IOP was measured before infusion and surgery and immediately after surgery.
At the end of operation Aldrete scores were evaluated.
Results and Discussion: In general, dexmedetomidine was well tolerated and no serious side or adverse effects were observed in the present study. The groups did not significantly with regard to age, weight, height, sex or duration of the operation (p > 0.05).
HR and MBP values were significantly reduced with dexmedetomidine in group I (p < 0.05). IOP was significantly reduced in the dexmedetomidine group. IOP was decreased at most by 28% with the dose of 0.2 μg/kg/h when measured after operation. Aldrete scores at 20 min was lower in group I than placebo group (p < 0.05). Postoperative VAS values were found to be significantly lower in group I (p < 0.05).
Conclusion: Our results suggest that dexmedetomidine 0.2 μg/kg/h produce sedation and a reduction of IOP with minimal haemodynamic changes in cataract surgery under periocular anaesthesia.
1 Virkkila M. Anaesthesia, 1993, 482-7.