Abstract

Introduction: Middle ear surgeries like tympanoplasty involve utilization of microscope in a small area. Slightest bleeding at surgical area would look larger due to magnifying effect of microscope. Controlled hypotension is a method by which the arterial blood pressure is decreased in a way to limit intra-operative blood loss and to provide the best possible surgical field for operating. In the present study, an attempt was made to compare the efficacies of Nitroglycerine and Esmolol and the quality of surgical field during controlled hypotensive anaesthesia induced by either of the two drugs intravenously when performing elective Tympanoplasty under General Anaesthesia.

Methods: 60 patients having ASA I or ASA II undergoing tympanoplasty under general anaesthesia was randomly allocated to two groups of 30 patients each using computer generated sequence. Sequence concealment was done using opaque sealed envelope technique. Group E(n=30) received Esmolol 500 mcg/kg bolus over 30 seconds followed by continuous administration at a dose of 25-300mcg/kg/minute to maintain mean arterial pressure at 60-65 mmHg 10 minutes before surgery. Group N(n=30) received Nitroglycerine at a dose of 0.5-2mcg/kg/min to maintain mean arterial pressure at 60-65 mmHg 10 minutes before surgery. Parameters to be measured are heart rate, SBP, DBP and MAP every 5 minutes.

Results: There was increase in the Heart Rate in the Group N as compared to Group E. SBP, DBP and MAP decreased in Group N as compared to Group E. The surgical blood loss and duration of surgery was lower in the Group E. Both Nitroglycerine and Esmolol are useful for controlled hypotensive anaesthesia but Esmolol given in the dose of 25-300 mcg/kg/min (after a bolus of 500 mcg/kg) effectively reduced the surgical blood loss and duration. It also enhanced the operative visibility better. There was no clinically significant bradycardia or any other side effects or complications noted with Esmolol.

Conclusion: Esmolol is a safe and superior agent to Nitroglycerine for controlled hypotension in tympanoplasty as it minimizes surgical blood loss, enhances the operative field visibility and reduces overall duration of surgery at higher MAP compared to Nitroglycerine.