Characteristic Electroencephalogram of General Anesthesia

Exclusion Criteria

• •Skin infection at the site of nerve block puncture; history of smoking and alcohol abuse, history of brain surgery, history of cerebral infarction, mental and neurological disorders (MMSE \< 18, 3D-CAM positive), history of taking any psychotropic or opioid drugs within 2 weeks, hearing impairment, cardiovascular disease, expected difficulty in airway management or sleep apnea syndrome, drug (including those with a history of allergic reaction to the test drug or contraindications for use) or food allergies, pregnant or lactating patients, patients or family members who refuse to participate, and those who refuse to undergo nerve block.