A Comparative Evaluation of Dexmedetomidine versus Midazolam-fentanyl for Sedation in Vitreoretinal Surgery under Peribulbar Anaesthesia

Introduction: Midazolam fentanyl (MDZ: FEN) combination is frequently used for intravenous sedation in ophthalmic surgeries in adults. Dexmedetomidine (DEX), is also indicated for procedural sedation. However, it may cause deeper sedation and patient non-coperation at recommended doses. Aims and objectives: To evaluate the efficacy and safety of low dose of i. v. dexmedetomidine (DEX) (0.25 microgm/kg) versus i. v midazolam-fentanyl (MDZ: FEN) (0.5mg/25microgm) for vitreoretinal surgeries under peribular anesthesia in adults. Materials and methods: In a randomized, double-blind, interventional study, 60 patients (30 each group) aged 20-60 years, scheduled for vitreoretinal surgery under peribulbar block were divided equally to receive either iv MDZ: FEN (0.5mg/25microgm) or iv DEX (0.25 microgm/kg) dose over 10 mins. The vital parameters, ramsay sedation score (RSS), surgeon satisfaction score& effect on respiration were noted. Results: The ‘DEX’ group patients had stable haemodynamics, level 3 sedation and surgeon satisfaction score of 2–3 (good to excellent operating conditions) with no respiratory depression. The sedation score (RSS) of 3 was achieved at approx 5.3 minutes in MDZ: FEN group as compared to 11.5 minutes in DEX group (pless than 0.001). The intraoperative mean blood pressure was significant higher in MDZ: FEN group at 30 to 75 minutes (pless than0.001). The post-operative nausea/vomiting was seen in 20 percent patients in MDZ: FEN group (pless than0.023) and none in low dose DEX group which was statistically significant. Conclusion: Low dose inj. DEX (0.25microgm/kg) is an effective alternative to inj MDZ: FEN (0.5mg/25microgm) and provides better (level 3) sedation score and stable haemodynamics, surgeon satisfaction and no post‑operative nausea/vomitting. Hence both drugs are efficacious but low dose DEX is better than MDZ: FEN in the study.