Effect of fentanyl addition to local anaesthetic in peribulbar block

Forty patients ASA I, II undergoing vitrectomy due to vitreous hemorrhage not associated with retinal detachment were divided into two groups randomly, each of them with 20 patients. In Control group patients received local anaesthetic only, while Fentanyl group receive 20 mcg fentanyl added to local anaesthetic, the onset and duration of lid and globe akinesia were assessed at 1,3,5 and 10 min. Postoperative VAS was recorded each hour up to 6(th) hour. The results show statistically significant difference between the two groups in the onset of lid akinesia. Fentanyl group had faster onset of lid akinesia and had significantly longer duration of akinesia (196.5 +/- 14.24 min). There is statistically significant difference between the two groups in the onset of globe akinesia at 3, 5 min. Fentanyl group had faster onset than Control group and had longer duration of globe akinesia (294 +/- 17.89 min). Fentanyl group had prolonged duration of analgesia 3.25+/-0.67 hr as compared to 1.85+/-0.67 in Control group, P=0.00 postoperatively. There were statistically significant differences between the two groups as regard the mean VAS in 1,2,3,4 hours, Fentanyl group had lower median pain score than Control group. Addition of fentanyl to local anaesthetic mixtures fasters the onset and prolong the duration of akinesia and improve quality of postoperative pain in peribulbar block.