Background
Researches to find a better adjuvant in regional anesthesia are still continued until now.
Methods
Sixty patients of American Society of Anaesthesiologists (ASA) grade I–III, aged between 18 and 70 years, scheduled for phacoemulsification cataract surgery were randomly assigned to two equal groups. Group C (control group) received 2 ml of a mixture of 2% lidocaine and 0.5% bupivacaine and Group D (dexmedetomidine group) received 2 ml of a mixture of 2% lidocaine and 0.5% bupivacaine plus dexmedetomidine (0.5 μg/kg). Onset and duration of sensory and motor block was recorded. Pain during administration of anesthesia and during surgery was graded using the verbal analogue scale and recorded. Intraocular pressure, hemodynamic, and sedation parameters were recorded before and after surgery.
Results
Onset of both sensory and motor block was significantly decreased in group D ( < 0.001,  = 0.004 respectively), and duration of sensory and motor block was more prolonged in group D than in group C ( < 0.001,  = 0.961). Pain during administration of anesthesia was significantly lower in group I compared with group II, and more patients in group I compared with group II were pain free, without a significant difference between the two groups. Intraocular pressure was significantly decreased in group D ( < 0.001). More sedation score was observed in group D ( = 0.022). Heart rate and mean arterial blood pressure were insignificantly decreased in group D more than in group C.
Conclusion
Dexmedetomidine is a safe and effective adjuvant to subtenon block in phacoemulsification cataract surgery.