Comparative study of nitroglycerin and esmolol for controlled hypotension in fess

Background: Functional Endoscopic Sinus Surgery (FESS) is a minimally invasive procedure for diseases of the nose and paranasal sinuses like chronic sinusitis and polypus rhinosinusitis. Intraoperative bleeding causing poor visibility of surgical field is a major concern during FESS and this may result in many complications. Controlled hypotension is a technique wherein arterial blood pressure is lowered in a deliberate but controlled manner to minimise blood loss and enhance operative field visibility. Aim: To compare the hypotensive efficacies of Nitroglycerin (NTG) and Esmolol (ESM) in terms of changes in heart rate (HR), systolic blood pressure, diastolic blood pressure, mean arterial pressure (MAP), duration of surgery and operative field visibilty assessment by surgeon using Average category scale (ACS) or Fromme scale, in patients undergoing FESS under General Anesthesia (GA). Methods: 80 ASA grade I and II patients aged between 18-60 years undergoing FESS under GA were divided into 2 groups of 40 each to receive either Inj. Esmolol 500 µg/kg over 30 seconds followed by infusion at 100-300 µg/kg/min or Inj. NTG at 5-10 µg/kg/min. All patients were premedicated with oral Alprazolam and Ranitidine on the previous night. In the operation theatre, all patients were premedicated with i.v. Glycopyrrolate, i.v. Midazolam and i.v. Fentanyl, and then induced with i.v. Propofol. Laryngoscopy and intubation was facilitated by i.v. Succinyl choline. Anaesthesia was maintained with Isoflurane vapour in balanced nitrous oxide/oxygen mixture and i.v Vecuronium for muscle relaxation. Heart rate, Systolic, Diastolic and Mean arterial blood pressure were assessed at 5, 10, 15 minutes and every 15 minutes from the start of infusion till completion of surgery. Visibility of the surgical field was rated by the surgeon using ACS with 0 being the driest and 5 making surgery impossible. Results: Intraoperative Heart rate was less in Esmolol group compared to NTG group. Both drugs produced desired hypotension but ideal operative conditions were achieved at a higher MAP of 80.5 ± 2.5 mm Hg in ESM group, while same operating conditions were achieved at lower MAP of 70.8 ± 1.2 mm Hg in NTG group. ACS scores were significantly low in ESM group compared to NTG group (p < 0.001). Mean duration of surgery was less in ESM group than NTG group (p < 0.001). Conclusion: Both drugs are safe and effective in providing optimal operating conditions but Esmolol is a superior agent to NTG for controlled hypotension in FESS under GA, as it minimizes surgical blood loss, enhances operative field visibility and reduces duration of surgery with minimal reduction in MAP. Absence of reflex tachycardia was the added advantage of ESM over NTG.