Objective To investigate the changes in hemodynamics and depth of anesthesia under monitored anesthesia care（MAC） in patients undergoing percutaneous dilatational tracheostomy（PDT）. Methods Forty-six patients with oral cancer were divided into two groups with 23 cases each: Local anesthesia group（group L） and MAC group（group M）. Local and intratracheal surface anesthesia were performed with 2% lidocaine in group L. Midazolam, propofol and fentanyl were added to group M after local and intratracheal surface anesthesia, then PDT was carried out. During the induction, observer’s assessment of alertness/sedation（OAA/S） scale was used to assess the depth of sedation. Mean arterial blood pressure（MAP）, heart rate（HR）, state entropy（SE） and response entropy（RE）were recorded before anesthesia（basal value, T1）, after local anesthesia（T2）, after intravenous administration/before incision（T3）, during incision（T4）, during dilating with stretching pliers（T5） and endotracheal intubation（T6）. A postoperative follow-up was taken in group M. Results MAP and HR increased significantly at T4-T6 in group L and decreased at T3（P
