Abstract: Objective To investigate the effect of ultrasound-guided anterior serratus plane block combined with laryngeal mask on postoperative analgesia and stress response in thoracoscopic surgery with autonomous breathing.
Methods 60 patients with elective thoracoscopic lobectomy were selected.All patients were divided into two groups：Group C（SAPB group）and group N.Blood glucose，norepinephrine and adrenaline were measured before anesthesia induction（T1），10 minutes after operation（T2），30 minutes after operation（T3），and 10 minutes after operation（T4）.The consumption of general anesthesia drugs，visual analogue scores at rest，cumulative sufentanil consumption and the times of PCA compression times were recorded.The recovery time of anesthesia，the time of first exhaust，the time of defecation and the days of hospitalizationwere recorded.
Results The contents of blood glucose，noradrenaline and adrenaline in the two groups increased at T4 ，compared with T1、T2、T3，the difference was statistically significant（P<0.05）.Compared with group N，the contents of blood glucose，noradrenaline and adrenaline in group C were lower（P<0.05）.Compared with group N，intraoperative anesthetic drug dosage，VAS score 24 hours after operation，PCA dose of sufentanil and PCA compression frequency in group C were lower than those in the control group，and the differences were statistically significant（P<0.05）.The recovery time of anesthesia，the time of first exhaust，the time of defecation and the days of hospitalization in group C were all shortened（P<0.05）.
Conclusion The application of ultrasound-guided anterior serratus block in thoracoscopic surgery can effectively inhibit perioperative stress response，provide good postoperative analgesia for thoracoscopic surgery，reduce the use of postoperative analgesic drugs，shorten the time of anesthesia recovery and hospital stay，and promote the postoperative recovery of patients.

Key words: ultrasound guidance, anteriorserratus plane block, spontaneous respiration, stress response, postoperative analgesia