The impact of two different doses of Dexmedetomidine to Local Anesthetic Mixture on the quality of single injection Peribulbar Block in Vitreoretinal operations

Objective: To evaluate the impact of adding two different doses of dexmedetomidine to local anesthetic mixture on the quality of single injection peribulbar block in vitreoretinal operations Design: A prospective, double-blinded and randomized study. Setting: carried out in operating room of our university hospital. Patients: The study included 120 patients with viteroretinal diseases who were scheduled for vitreoretinal operations during the period from April 2016 to March 2017. Interventions: 120 patients were randomly allocated to three groups of 40 patients each. Group I (the control group) received 5-7 ml mixture of lidocaine 2% and Levobupivacaine 0.5% with 120 IU of hyaluronidase, group II received5- 7 ml mixture of lidocaine 2% and Levobupivacaine 0.5% with 120 IU of hyaluronidase +15 µgdexmedetomidine, and group III received5- 7 ml mixture of lidocaine 2% and Levobupivacaine 0.5% with 120 IU of hyaluronidase + 30 µg dexmedetomidine Measurements: The primary outcome was to evaluate the impact of adding two different doses of dexmedetomidine on the onset of globe anesthesia and akinesia. Secondary outcomes were the duration of globe anesthesia and akinesia, overall patient satisfaction and surgeon satisfaction. Results: The onset of globe anesthesia was significantly shorter in group II and III in comparison with group I. Adding dexmedetomidine to the local anesthetic mixture prolonged the duration of globe analgesia, and this difference was statistically significant in group II and III in comparison with the group I. Conclusion: Adding dexmedetomidine to a mixture of lidocaine 2% and levobupivacaine/hyaluronidase mixture in single injection peribulbar block shortened sensory and motor block onset, extended the analgesia period and the motor block duration with high patient and surgeon satisfaction