During endoscopic sinus surgery (ESS), epinephrine local injection and controlled hypotension is essential in order to increase the visibility in the operative field and reduce the risk. This study is comparing of dexmedetomidine and remifentanil before epinephrine local injection for controlled hypotension during ESS.

During endoscopic sinus surgery (ESS), epinephrine local injection and controlled hypotension is essential in order to increase the visibility in the operative field and reduce the risk.

Epinephrine local injection and controlled hypotensive anesthesia is commonly used in several surgical interventions using different techniques. However, choosing the ideal agent is still a controversial topic.

In the current study, the effects and safety of remifentanil, which is an μ opioid receptor agonist and dexmedetomidine, an α-2 agonist; when used before epinephrine local injection for controlled hypotension in ESS, are compared.

After obtaining Institutional Review Board approval and written informed consent, 40 patients is enrolling in this study.

Participants is divided by two groups randomly as the Dexmedetomidine group and the Remifentanil group.

A correctly sized facemask and 100 % oxygen was used for pre-oxygenation. General anesthesia was induced with iv Propofol 1.5-2 mg kg-1. Endotracheal intubation was performed with the aid of iv Rocuronium 0.6 kg-1. Ventilation was controlled with 50% air in oxygen to maintain end-tidal carbon dioxide pressure at 30-36 mmHg. Desflurane was used for maintenance.

Before epinephrine injection, In group Remifentanil, Participants received 1 mcg kg-1 iv loading dose of remifentanil over a period of 60 seconds. Later, an infusion was started at the rate of 0.2-0.4 mcg kg-1 h-1. The infusion rate was adjusted according to the Participants response, to achieve a mean arterial pressure between 60 and 75 mmHg. In group Dexmedetomidine, patients received a 1 mcg kg-1 loading dosage of dexmedetomidine within 10 min and later, infusion was started at the rate of 0.4-0.8 mcg kg-1min-1. The infusions began before tracheal intubation in both groups. Standard dose epinephrine local infiltration was administered to the nasal passages by the surgeon.

Systolic Arterial Pressure,Diastolic Arterial Pressure,Mean arterial blood pressure, Heart Rate were recorded every 5min, from the beginning of anesthesia and every 1min, from the epinephrine local injection. Perioperative hypotension and bradycardia were defined as mean arterial blood pressure < 50 mmHg or 50 beat/min respectively. Ephedine was administered intravenously for the treatment of hypotension. Atropine 0.5 mg was administered intravenously for the treatment of bradycardia.

All infusions were stopped 5 min before the end of surgery. After surgery, the surgeon evaluated the dryness of the surgical area. Recovery time was recorded in the postoperative period. An investigators employing the Modified Observer's Assessment of Alertness/Sedation Scale assessed recovery.

Inclusion Criteria:

• American Society of Anesthesiologist[ASA] class 1-2
• scheduled Endoscopic sinus surgery
• written informed consent

Exclusion Criteria:

• allergy of opioids, neuromuscular blocking drugs or other medications used during general anesthesia
• known or suspected upper respiratory infection
• suspected difficult tracheal intubation
• Uncontrolled Hypertension
• known or suspected psychologic disorder
• known or suspected significant renal dysfunction
• known or suspected severe hepatic dysfunction
• known or suspected significant cardiovascular dysfunction