Total intravenous anaesthesia will be induced with 2mg/kg propofol and 0.3mg/kg esketamine, slow injection.

During the painless abortion surgery, if the MOAA/S scores > 1 or body movements occur, supplemental 0.25 mg/kg propofol (IV) will be administrated.

0.3mg/kg esketamine will be co-administrated in both arms

MAP level will be monitored and recorded at 4 time points, including the entry into the operation room (Time 0), in sedation when vaginal dilator is placed (Time 1), in sedation when curettage begins (Time 2), and postoperative awakening (Time 3).

HR will be monitored and recorded at 4 time points, including the entry into the operation room (Time 0), in sedation when vaginal dilator is placed (Time 1), in sedation when curettage begins (Time 2), and postoperative awakening (Time 3).

The adverse events will be monitored and recorded during the operation and post-operation. AE will include: respiratory depression (defined as SpO2< 95%), hypotension (defined as systolic arterial pressure < 80 mmHg, or decreased baseline systolic blood pressure > 20%), hypertension, bradycardia (defined as decrease in HR < 50/min), number of body movements, injection site pain and nausea and vomiting.

It will be assessed by Visual Analogue Scale (VAS) pain score. The VAS consists of a 10cm line, with two end points representing 0 ('no pain') and 10 ('pain as bad as it could possibly be').