Effect of dexmedetomidine on convalescence quality after general anesthesia and postoperative delirium, and on cognitive function in elderly patients undergoing lower limb surgery

Purpose: To investigate the effect of different doses of dexmedetomidine on the quality of postoperative recovery, incidence of postoperative delirium, and cognitive function in elderly patients undergoing lower limb surgery. Methods: A total of 112 patients who received treatment in the Department of Anesthesiology, Affiliated Hospital of Inner Mongolia Medical University, Hothot, China from January 2021 to January 2023 were divided into 3 groups, consisting of low-dose group (35 patients received 0.2 mg/kg), medium-dose group (39 patients received 0.4 mg/kg), and high-dose group (38 patients received 0.6 mg/kg). Parameters including, convalescence quality of general anesthesia, incidence of postoperative delirium, adverse reactions, Mini- mental State Examination (MMSE) scores, sedation effect (Ramsay), analgesia effect (visual analogue scale (VAS)), and stress indices, viz, norepinephrine (NE), epinephrine (E), and cortisol (COR) levels), were evaluated and compared. Results: There was no significant difference in tracheal extubation time, recovery time of spontaneous breathing, calling eye-opening time, or full awakening time among the three groups (p > 0.05). However, MMSE score was significantly higher in low-dose group on days 1 and 3 after surgery (p < 0.05) and VAS scores were significantly higher in low-dose group at 12 and 24 h after recovery compared to other groups (p < 0.05). Ramsay score was significantly higher in high-dose group (p < 0.05). Levels of NE, E, and COR were significantly lower in medium-dose group compared to other groups (p < 0.05). Incidence of adverse reactions were significantly lower in low and medium-dose groups compared to high- dose group (p < 0.05). Conclusion: Medium-dose dexmedetomidine demonstrates favorable sedative and analgesic effects with minimal impact on cognitive function and stress response in elderly patients undergoing lower limb surgery. Furthermore, it does not affect quality of postoperative recovery nor incidence of postoperative delirium. More large-scale, randomized controlled studies are needed to confirm these results.