Proper preoperative sedation can reduce patients' anxiety, enhance patients' cooperation and reduce perioperative complications. The investigators would explore the sedative effects of dexmedetomidine (DEX) with the administration of oral, intravenous and nasal drops, and detect DEX blood concentration in 15 participants, respectively. Pharmacokinetic parameters are detected at 8 time points ( before DEX administration, 10 min, 20 min, 30 min, 45 min, 60min, 90min and 120 min after administration). 3 ml arterial blood was collected at each time point. The blood samples are detected by mass spectrometer. The aim of this study is to investigate appropriate administration time and route for DEX sedation.

Inclusion Criteria:

• 45 participants who undergo tympanoplasty would be enrolled after signment the informed consent.

Exclusion Criteria:

• The participants were excluded with any diseases about respiration, circulation, liver and kidney.