COMPARISON OF DEXMEDETOMIDINE 0.5MCG/KG IV OR 1MCG/KG IV WITH SALINE AS CONTROL FOR MONITORED ANAESTHESIA CARE IN POSTERIOR SEGMENT OPHTHALMIC SURGERY. A RANDOMIZED CONTROLLED TRIAL

Abstract

Background: Conscious sedation is often required during ophthalmic surgeries to ensure patient comfort and cooperation. Dexmedetomidine, an alpha-2 adrenergic agonist, has gained attention for its sedative and analgesic properties. This study investigates the effectiveness and safety of two doses of dexmedetomidine (0.5 µg/kg and 1 µg/kg) compared to a saline placebo in providing sedation for posterior segment ophthalmic surgeries.

Methodology: A double-blind, block-randomized controlled trial was conducted on 75 patients undergoing posterior segment ophthalmic surgeries under local anesthesia. Participants were randomly assigned into three groups (n=25 each) to receive either dexmedetomidine 0.5 μg/kg (Group DL), 1 μg/kg (Group DH), or placebo (Group C) infused over 10 minutes. Sedation, analgesic requirements, hemodynamic parameters, and recovery profiles were assessed. Data were analyzed using STATA 10.1, with ANOVA, Chi-square test, and Games-Howell post hoc analysis applied; p<0.05 was considered statistically significant.

Results: Baseline demographic and clinical characteristics were comparable across all groups with no significant differences. Intraoperatively, sedation scores were significantly higher in the DH and DL groups compared to the Control group during the first 60 minutes (p < 0.0001). Fewer patients in the DH and DL groups required rescue midazolam and fentanyl, and their mean dosages were significantly lower than in the Control group (p < 0.0001). Respiratory parameters remained stable and comparable across groups. Adverse events were mild and not statistically different between groups. Overall, DH and DL groups demonstrated superior sedation and analgesia profiles with minimal side effects.

Conclusion: Both 0.5 µg/kg and 1 µg/kg doses of dexmedetomidine were effective in providing conscious sedation during posterior segment ophthalmic surgeries, with no significant difference in efficacy. However, the 0.5 µg/kg dose was associated with fewer side effects, indicating a better safety profile. Therefore, a 0.5 µg/kg dose is recommended for monitored anesthesia care in these procedures.