Comparative Study of Oral Clonidine Vs Oral Metoprolol for Induced Hypotensive Anaesthesia in Functional Endoscopic Sinus Surgery

Background: Over the last few years, considerable interest in endoscopic surgery of the paranasal sinuses has been expressed, which is a minimally invasive technique. Complications related to this technique often arises due to excessive bleeding during surgery. This study compares oral Clonidine (centrally acting a-2 agonist) and oral Metoprolol (cardioselective beta blocker) used as premedication in functional endoscopic sinus surgery to evaluate improvement in operative field. 

Method: This prospective, randomized, double blind study included 50 ASA Grade I and II patients, aged between 18-60 years, who were equally divided into two groups as Group I (received oral Metoprolol 50 mg) and  Group II (received oral Clonidine 3mcg/kg ) 90 min prior to surgery. Pulse Rate and blood pressure were recorded at different time intervals including before starting the drug, before pre medication, after intubation, every 5 minutes thereafter for 30 minutes, every 10 minutes thereafter till the end of surgery and after extubation. Assessment of surgical field was done by using Fromme et al scale adapted by Boezaart et al. 

Results: Metoprolol was more effective in controlling heart rate intra operatively than Clonidine, whereas Clonidine was more effective than Metoprolol in maintaining better surgical field that too in lower doses as compared to the one used in previous studies. Both the drugs were effective in preventing the haemodynamic response associated laryngoscopy, intubation and surgical stimulus.

Conclusion: Clonidine is more effective than Metoprolol in reducing intra operative bleeding and maintaining better surgical field even in low doses of 3 mcg/ kg.