Comparison of the Effects of Dexmedetomidine and Lidocaine on Stress Response and Postoperative Delirium of Older Patients Undergoing Thoracoscopic Surgery: A Randomized Controlled Trial

PURPOSE: We investigated the effects of intraoperative intravenous lidocaine or dexmedetomidine infusion on inflammatory factors and cognitive function in patients undergoing thoracoscopic surgery. PATIENTS AND METHODS: Patients aged >65 years undergoing elective thoracoscopic lobectomy or segmentectomy were randomly grouped as dexmedetomidine group (group D), lidocaine group (group L), and control group (group C). The plasma cortisol, interleukin-6, and tumor necrosis factor-α concentrations were measured before anesthesia (T0) and immediately (T1), 24 h (T2), and 48 h postoperatively (T3). Postoperative delirium (POD) was assessed by 3D-CAM on days 2 and 7. RESULTS: The cortisol concentrations decreased for all groups at T1 from T0 although they were significantly higher at T2. Group L had significantly lower interleukin-6 concentrations at T1 and T2 than the other groups (P<0.05). The interleukin-6 concentrations were significantly higher at T1, T2, and T3 than at T0 for all the groups, significantly lower for groups D and L than for group C at T1 and T2 (P<0.05), and significantly lower for group L than for group D at T2 (P<0.05). The tumor necrosis factor-α concentrations were significantly higher at T1, T2, and T3 than at T0 for all the groups and significantly lower for groups D and L than for group C at T1 and T2 (P<0.05), although they were not statistically significantly different for groups D and L. There were no statistically significant differences in the postoperative incidence of POD between the three groups on days 2 and day 7. CONCLUSION: Intraoperative continuous intravenous lidocaine or dexmedetomidine infusion reduced surgical stress and inflammatory responses. The inhibitory effect of lidocaine on surgical stress remained significant for up to 24 h postoperatively without affecting patient awakening. However, the administration of either drug failed to prevent postoperative POD.