Optimal Dose of Dexmedetomidine Retrobulbar Anesthesia during Phacoemulsification Cataract Surgery

The cataract surgery anesthesia should be to make the procedure as safe and as satisfactory as possible for all concerned. The recent progress in anesthesia and surgery now allow cataract extraction to be done with minimal physiological changes to the patient. We aimed in the study to compare between two different doses of dexmedetomidine combined with lidocaine and bupivacaine during retrobulbar anesthesia for cataract extraction by phacoemulsification.

This study was done on forty patients with cataract. The patients were enrolled in two groups: Group (A):Twenty patients were received 1.5 ml 2% lidocaine + 1.5 ml 0.5% bupivacaine + 0.25 μg/kg of dexmedetomidine and Group (B): Twenty patients were received 1.5 ml 2% lidocaine + 1.5 ml 0.5% bupivacaine + 0.5 μg/kg of dexmedetomidine.

The globe anesthesia duration, globe, and lid akinesia were significantly longer in the Group B than in the Group A (P < 0.05). Intraocular pressure decreased through the first 15 min after anesthesia in the two groups, and the changes were not significant between the two groups but highly significant in every group when compared to its baseline reading. As regards the conscious level in the two groups, there was a significant difference (P < 0.001). Group A is higher regarding score 2 and 3, and Group B higher in score 4.

We concluded that dexmedetomidine 0.25 μg/kg, when added to retrobulbar block for cataract surgery, will significantly increase the duration of retrobulbar block and improve both the surgeon and the patient satisfaction.