Cough suppression during emergence and tracheal extubation from general anaesthesia has become an important issue as part of patient safety. Cough arised from the mechanical irritation of endotracheal tube and cuff could be accompanied by various adverse effects such as laryngospasm, hypertension, tachycardia, arrhythmia and increase of intracranial, intraocular, or intra-abdominal pressure.

Several cough-preventing strategies have been proposed for smooth emergence, such as opioids, dexmedetomidine or lidocaine. Maintenance of remifentanil infusion during emergence has been reported to be an effective method in reducing cough and cardiovascular change without delay of recovery. In previous studies, the effetive effect-site concentraions for 95% of adults (EC95) for preventing cough are a little different depending on anaestheic agent, type of surgery and sex, ranged from 2.14 to 2.94 ng/ml. However, since most of these studies are for sing lumen endotracheal tube, similar preventing effect would not be expected for double lumen tube (DLT) because of its large diameter and long length. Another problem is higher concentration of remifentanil more than 2.5 ng/ml could not guarantee the safety after extubation. The efficacy of a single IV bolus of lidocaine for the prevention of cough has been the subject of numerous trials.

Therefore, combined use of lidocaine and remifentanil could effectively prevent emergence cough for DLT without the risk of high concentration of remifentanil.

Inclusion Criteria:

• Patients needs for double lumen tube intubation for one lung ventilation during surgery with ASA (American society of Anesthesiologists) class I or II

Exclusion Criteria:

• Gastroesophageal reflux disease
• Obese patients (BMI > 30)
• Recent upper respiratory infection history (within 3 weeks)
• Asthma history
• Anticipating difficult airway