Comparative Study Between the Efficacy of Verapamil and Bisoprolol on Reduction of Bleeding During Endoscopic Sinus Surgery Under General Anaesthesia.

Intra-operative bleeding presents a larger obstacle to endoscopic visualization. Blood obscures the anatomy of the surgical field and dirties the endoscope lens causing greater difficulty with visualization. This situation increases the risk of complications, including brain injury, orbital or optic nerve injury, and catastrophic bleeding from major vessels (e.g., internal carotid artery) 1.

Endoscopic sinus surgery (ESS) is a minimally invasive technique used to restore sinus ventilation and function in patients with recurrent acute or chronic infective sinusitis in whom medical therapy has failed. The term ESS is used to draw attention to the potential for reestablishing natural mucociliary clearance mechanism, drainage and aeration of sinuses, whilst maintaining as much of the normal anatomy as possible. Over last few years this technique has become popular worldwide due to its minimally invasive nature and preservation of mucosa2.

Continued bleeding into the surgical field during ESS not only impairs endoscopic vision but can lead to complications3. Compared with conventional anesthesia, total intravenous anesthesia (TIVA) has been previously reported to result in reduced blood loss when used for FESS. However, few recent studies point out that TIVA may not significantly reduce blood loss 4-5.

Controlled hypotension has been used to reduce bleeding and the need for blood transfusions, and provide a satisfactory bloodless surgical field . Controlled hypotension is defined as a reduction of the systolic blood pressure to 80-90 mm Hg, a reduction of mean arterial pressure (MAP) to 50-65 mm Hg or a 30% reduction of baseline MAP 6. The physiological principle which underlies hypotensive anesthesia is a natural survival mechanism. When profuse bleeding occurs, the blood pressure drops. This drop leads to a reduction or cessation of the bleeding, blood pressure stabilization, and recovery. Accordingly, reducing the patient's blood pressure during surgery can potentially reduce

overall bleeding. Since bleeding in the surgical field is also reduced, the surgical field operating conditions are improved 7 .