Dexmedetomidine microneedle patch for preoperative sedation in young children

Inclusion Criteria:

* Aged 2 years to 6 years (inclusive ), any genders;
* Body weight meeting the criteria:
* Scheduled to undergo general anesthesia for surgery/procedure
* American Society of Anesthesiologists（ASA） I\~II
* Provide written informed consent from the legal guardian

Exclusion Criteria:

* Allergy to any component of the Dexmedetomidine Hydrochloride Microneedle Patch, history of allergy to other sedative drugs, or known allergy to α2-adrenergic receptor-related products or excipients;
* Having received other sedative-hypnotic or analgesic drugs prior to randomization, where the time since last dose is less than 7 half-lives;
* History of bronchial asthma, chronic respiratory diseases, or other severe respiratory system diseases;
* History of neurological diseases such as ischemic encephalopathy encephalopathy, craniocerebral injury, etc., which in the investigator's judgment may affect the evaluation of the investigational product;
* History of thoracic, cardiac, or brain surgery;
* Presence of large areas of skin damage or skin conditions unsuitable for topical patch application on the inner aspects of both forearms or the outer aspects of both thighs;
* Abnormal liver/kidney function test values (ALT or AST \>1.5 times the upper limit of normal \[ULN\], or bilirubin \>1.5 × ULN, or serum creatinine \>1.5 × ULN);
* Severe cardiovascular diseases (e.g., fulminant myocarditis, high-grade or third-degree atrioventricular block, sick sinus syndrome, severe arrhythmia, cardiomyopathy, severe pulmonary hypertension, pulmonary atresia, heart failure);
* Anemia requiring treatment, as judged by the investigator (hemoglobin \<80 g/L);
* Use of highly selective α2 agonists or antagonists prior to randomization, where the time since last dose is less than 7 half-lives;
* Participation in another clinical trial (meaning having received an investigational drug or device) within 3 months prior to screening;
* Presence of severe psychiatric illness at screening leading to inability or unwillingness to cooperate;
* Other situations deemed by the investigator as unsuitable for inclusion.