Dexmedetomidine Combined With Transcutaneous Vagus Nerve Stimulation (taVNS) Can Reduce the Incidence of PTSD in Trauma Patients After Surgery

Inclusion Criteria: 1. Aged 18-80, of either gender, requiring emergency surgery due to trauma (such as car accidents, falls, engineering accidents, etc.). 2. No confirmed PTSD before enrollment. 3. The American Society of Anesthesiologists (ASA) physical status classification is divided into grades I-III (Grade I: healthy body and normal organ function; Grade II: mild comorbidities with good functional compensation; Grade III: severe comorbidities with limited mobility but able to cope with daily activities). 4. Voluntarily sign the informed consent form and be able to cooperate with the 1-month postoperative follow-up assessment (including CAPS-5 interview, scale completion, etc.) Exclusion Criteria: 1. Patients with severe craniocerebral or spinal cord injury, compensatory phase of hemorrhagic shock, or severe cardiovascular and cerebrovascular issues such as second-degree or higher-degree atrioventricular block, and baseline heart rate \<50 beats per minute. 2. Hepatic and renal insufficiency (transaminase \> 2 times the upper limit of normal, creatinine \> 1.5 times the upper limit of normal), coagulation dysfunction (INR \> 1.5), or history of alcohol abuse or drug dependence within the past 6 months. 3. History of neuropsychiatric disorders (such as schizophrenia, bipolar disorder), previous PTSD history, or severe visual, auditory, or language impairments, making them unable to cooperate with scale assessments. 4. Allergic to dexmedetomidine, or with damaged/infected skin at the tVNS stimulation site (cavity of the ear concha), or implanted with a cardiac pacemaker (contraindication to tVNS). 5. Pregnant or lactating women, or those who plan to receive other PTSD interventions (such as psychotherapy, anti-anxiety medications) after surgery and may withdraw from follow-up midway.