Efficacy of different dexmedetomidine regimens in producing controlled hypotensive anesthesia during functional endoscopic sinus surgery

Background
The study was designed to assess the ability of dexmedetomidine in different regimens to produce controlled hypotensive anesthesia during functional endoscopic sinus surgery in adults and the need to add an additional hypotensive agent in the form of nitroglycerin to achieve the target MAP.
Methods
In this blinded randomized controlled trail, 45 Patients, aged from 18 to 50 years, ASA physical status I and II, underwent endoscopic sinus surgery were enrolled in the study. Before induction of GA, all patients received bolus dexmedetomidine 1 μ/kg iv more than 10 min. After induction, Patients were randomly allocated into three groups, group Dex-0.4, in which patients received dexmedetomidine infusion as 0.4 μg/kg/h, group Dex-0.8, in which patients received dexmedetomidine infusion as 0.8 μg/kg/h and group Dex-P, in which patients received saline infusion. The target MAP was 55–65 mmHg, if not achieved by the infused study drug, nitroglycerin infusion was added in a titrating manner started with 0.1 μg/kg/min and increased gradually till the target MAP is reached. The surgical field quality was assessed by using Fromme et al. bleeding score.
Results
The intraoperative MAP in group Dex-P and group Dex-0.8 was maintained within target range at all time intervals. In group Dex-0.4, the MAP showed fluctuation to fall below and increased above the target range at different time intervals. Unlike the other two groups, no nitroglycerin infusion was needed in group Dex-0.8. Fromme et al. bleeding score showed the lowest values in Dex-0.8 group and the highest values in group Dex-0.4. The differences between the three groups were statistically significant with ( < 0.05).
Conclusion
Dexmedetomidine as bolus 1 μg/kg iv followed by iv infusion of 0.8 μg/kg/h or dexmedetomidine as pre-induction bolus 1 μg/kg iv followed by nitroglycerine iv infusion significantly decreased the mean arterial blood pressure to target values and provide satisfactory field quality.