Abstract: Objective To investigate the effects of stele ganglion block (SGB) on postoperative nausea and vomiting (PONV) and acute stress disorder in elderly patients after thoracoscopic surgery under general anesthesia. 
Methods A total of 92 elderly patients undergoing elective thoracoscopic lung lesion resection in the Affiliated Hospital of Xuzhou Medical University were selected and divided into research group (n=46) and control group (n=46) by random number table method. Both groups received general anesthesia and the research group was given SGB under ultrasound guidance with 0.25% ropivacaine 4 mL. Postoperative indexes, postoperative pain, PONV, acute stress disorder, stress response and related proteins were compared between the two groups. 
Results The dosage of remifentanil (1 653.08±69.76) μg and propofol (417.34±45.06) mg in the study group were lower than those in the control group (1 725.14±75.62) μg and （487.09±51.23） mg (P＜0.05). The recovery time of the study group (15.18±2.38) min was shorter than that of the control group (19.37±3.45) min (P＜0.05). There was no statistically significant difference in the first exhaust time and first getting out of bed time between the two groups (P＞0.05). Interactions between two groups of visual analog scores (VAS): between groups, between time points, and between groups and time points. The difference was statistically significant (P＜0.05), and there was a significant difference in PONV grading between the two groups (P＜0.05). The incidence of PONV 24 hours after surgery in the study group (21.74%) was lower than that in the control group (54.35%) (P＜0.05). There was a statistically significant difference (P＜0.05) in the interaction between two groups of acute stress disorder scale (ASDS) scores, including between groups, time points, and between groups and time points. 24 hours after surgery, the levels of serum cortisol (CORT), norepinephrine (NE), phosphorylated tau-181 (p-tau-181), and β-amyloid 1-42 (β-amyloid 1-42, A β 1-42) in both groups increased (P＜0.05), while the study group was lower than the control group (P＜0.05). 
Conclusion SGB can reduce the amount of anesthesia in elderly patients undergoing thoracoscopic surgery, reduce the risk of PONV, and alleviate symptoms related to acute stress response. 

Key words: thoracoscopy, stellate ganglion, stress disoders, traumatic, acute