Abstract / Summary
Abstract Objective To observe the effect of transcutaneous auricular vagus nerve stimulation (TAVNS) on postoperative delirium (POD) in elderly patients undergoing colorectal cancer surgery, and to explore its possible anti‑inflammatory and neuroprotective mechanisms. Methods A total of 180 elderly patients (age ≥ 65 years, ASA grade I–II) scheduled for elective laparoscopic radical resection of colorectal cancer were enrolled and randomly divided into a TAVNS group, a sham stimulation group, and a blank control group, with 60 cases in each group. The TAVNS group received daily electrical stimulation of the auricular concha region (30 min, 1 mA, 20–30 Hz) from 1 day before surgery to 3 days after surgery. The sham group received stimulation with the same parameters but at non‑vagus areas of the auricle, while the blank control group received no intervention. The incidence of POD was assessed using the 3‑Minute Diagnostic Interview for CAM‑Defined Delirium (3D‑CAM) at 1 day before surgery and at 1, 3, and 7 days after surgery. Serum levels of neuron‑specific enolase (NSE), S100β protein, tumor necrosis factor‑α (TNF‑α), and interleukin‑6 (IL‑6) were measured before surgery, at the end of surgery, and at 1 and 3 days postoperatively. Results A total of 174 patients (58 per group) completed the study. The incidence of POD in the TAVNS group at 1, 3, and 7 days postoperatively was significantly lower than that in the sham and blank control groups (P < 0.05), with no significant difference between the latter two groups (P > 0.05). Serum levels of NSE, S100β, TNF‑α, and IL‑6 in the TAVNS group at 1 and 3 days postoperatively were also significantly lower than those in the other two groups (P < 0.05), while no statistically significant differences were found between the sham and blank control groups for any of these markers (P > 0.05). Conclusion Transcutaneous auricular vagus nerve stimulation can effectively reduce the incidence of postoperative delirium in elderly patients undergoing colorectal cancer surgery. Its effect may be related to the inhibition of central nervous system injury markers (NSE and S100β) and inflammatory cytokines (TNF‑α and IL‑6).