EFFECT OF ADDING FENTANYL AND/OR CLONIDINE TO LOCAL ANESTHETIC ON PROLONGATION OF THE PERIBULBAR BLOCK IN CATARACT SURGERY

Peribulbar block became more popular than retrobulbar block in intraocular surgeries because it is more simple and safer. This study was done to explore addition of some drugs to LA may prolong the duration of peribulbar block with the possibility of performing relatively lengthy operations through single injection. Patients and methods: 120 patients were enrolled in this study, they were classified randomly into four groups (group C=received 30mcg clonidine, group F=received 20mcg fentanyl, group F+C=received 15mcg clonidine and 10mcg fentanyl, and group S=received 2 ml saline in addition to the LA mixture into the peribulbar block. Results: As regards the movement score at 5 and 10 min after injection, group F+C had the lowest significant scores while group S had the highest significant scores, no significant differences between group C and group F. Group F+C recorded the lowest movement score at 2 and 3 hours after injection, group C is significantly lower than group F and group S but only at 2 hours. Conclusion: The addition of clonidine alone to local anesthetic solution in peribulbar block prolonged the duration of block for up to 2 hours only. The addition of fentanyl alone to local anesthetic solution could not prolong the duration of the block, while the addition of both clonidine and fentanyl to local anesthetic solution prolonged the duration of the block for up to 3 hours. So this offered the most satisfactory block for surgical conditions up to 3h duration after the end of peribulbar injection.