Comparative evaluation of oral metaprolol vs oral clonidine as premedication in induced controlled hypotensive anaesthesia for patients undergoing functional endoscopic sinus surgery under general anaesthesia

Anaesthesia for Functional endoscopic sinus surgery is a challenging job. The surgeons’ operating field itself is very small and surrounded with mucus membranes. It is imperative for the surgeons to look at a clear surgical field in order to identify the diseased tissue properly. A small amount of blood within the field is enough to occlude the view through the endoscope making things difficult for the surgeon, and incomplete removal of the diseased tissue will cause the disease to reoccur. Anaesthesiologists have devised various techniques to prevent this bleeding, of which induced hypotension has stood the test of time. This surgery per se is not a major one by its standards and surgeons recently have been trying to accomplish FESS as a daycare surgery. A good premedication with an antihypertensive agent can help to minimize the amount of volatile agents and vasodilators used to induce hypotension, thereby ensuring much hemodynamic stability and speedy recovery from anaesthesia. Thus I have chosen to study and compare the effects of clonidine and metoprolol as oral premedicants for the same. This study proposes to analyze the anaesthetic challenge of keeping the operating field free of blood through pharmacological therapy. It compares how premedicating with either atenolol or clonidine affects the conduct of the fixed anaesthesia protocol evolved in our institute on patients undergoing FESS procedure under GA, and requiring a hypotensive technique to improve operating conditions.