Fentanyl is expected to suppress tracheal tube-induced cough during emergence from general anaesthesia through binding to its receptors in the brainstem. However, it has not been proven if fentanyl has a complication-free, dose-dependent effect on cough suppression during emergence from sevoflurane anaesthesia. The purpose of this study is to evaluate the relationship between fentanyl doses and cough suppression during emergence from sevoflurane anaesthesia.

Inclusion Criteria:

• the patients undergoing general anaesthesia for elective thyroidectomy due to thyroid neoplasm.
• ASA I-II.
• 20-59 years old.
• female only.

Exclusion Criteria:

• signs of difficult intubation.
• risks for perioperative pulmonary aspiration.
• history of chronic respiratory disease.
• recent upper respiratory track infection.
• previous and recent smoking history