Comparison of three different loading doses of dexmedetomidine for controlled hypotension during functional endoscopic sinus surgery under general anaesthesia- A randomised controlled study

Background and Aim: Deliberate hypotension to provide bloodless surgical field gives better visibility of the operative field, with reduced risk of injury to adjoining structures. This present study was conducted to compare three loading doses of dexmedetomidine for controlled hypotension in FESS surgery under GA.Methods: Sixty patients aged between 18-60 years of either sex belonging to American Society of Anesthesiology I and II scheduled for FESS were randomly allocated to one of the three groups. Patients in group I, II and III received dexmedetomidine loading infusion at a rate of 1 μg kg-1, 0.8 μg kg-1 and 0.6 μg kg-1 respectively over 10 minutes followed by continuous infusion of 0.5 μg kg-1 h-1. The primary goal was to provide a MAP in a range of 60 - 70 mmHg before the start of surgery. Results:It was found that Mean HR as well as MAP was significantly lower in group I as compared to group II and III at multiple points. Also, time to achieve MAP was significantly lower in group I. (p < 0.001). surgical field visibility and surgeon satisfaction was better in group I.Conclusion: We concluded that using IV dexmedetomidine as an adjunct to other anesthetics is an acceptable approach to provide controlled hypotension. Administration of a loading dose of 1 µg kg-1 and 0.8 µg kg-1 compared to 0.6 µg kg-1, provides better surgical field conditions in terms of bleeding and visibility.