Comparative Study between Effects of Addition of Fentanyl versus Dexmedetomidine to Local Anesthetic Mixture for Peribulbar Block for Cataract Surgery

Background: regional anesthesia is currently more preferable than general anesthesia in ophthalmic surgery and include many types as; peribulbar (extraconal) and retrobulbar (intraconal) anesthesia. Peribulbar block is commonly used because there is reduced risk of globe perforation and optic nerve damage in different to retrobulbar block, but it needs sometimes block supplementations to improve the quality of the block such as clonidine and hyaluronidase. Also, fentanyl and dexmedetomidine was added in this study as an adjuvant to local anesthetics in peribulbar block for cataract surgery.
Objective: the aim of this study was to evaluate and compare the effect of adding fentanyl and dexmedetomidine as adjuvants to local anaesthetic mixture in peribulbar block as regards duration (anesthesia and akinesia), efficacy and pain relief.
Patients and Methods: in this study sixty patients of ASA I-III of both gender, aged 30-60 years arranged into three equal groups (group S, group F and group D) received peribulbar block for phacoemulsification with intraocular lens implantation operation. Group F and group D received fentanyl and dexmedetomidine respectivly with local anaethetics (LA) solution and showed statistically significant difference in onset and duration of globe akinesia respectively compared to group C which received local anaethetics (LA) solution only.
Results: the onset of globe analgesia was significant in group F and group D compared to Group S. Postoperative pain was assessed by using a 5-points verbal rating score and recorded data showed significant difference between the three groups with better postoperative pain control in group F and group D. There was no statistical significant difference between the two groups as regarding the hemodynamics (MBP, HR and SPO2) and the incidence of complications.
Conclusion: the current study concluded that adding fentanyl or Dexmedetomidine to local anaethetics (LA) in peribulbar block significantly reduced the time of onset of globe akinesia and analgesia and reduced the need for second injection. Also, it increased the duration of globe akinesia and analgesia with better postoperative pain control.