Effect of Dexmedetomidine on Postoperative Plasma Neurofilament Light Chain in Elderly Patients Undergoing Thoracoscopic Surgery: A Prospective, Randomized Controlled Trial

Purpose: Dexmedetomidine exerts a neuroprotective effect, however, the mechanism underlying this effect remains unclear. This study aimed to explore whether dexmedetomidine can reduce the increase in neurofilament light chain (NfL) protein concentration to play a neuroprotective role during thoracoscopic surgery.<br /> Patients and Methods: Patients aged >= 60 years undergoing general anesthesia for thoracoscopic surgery were randomly assigned to receive dexmedetomidine (group D) or not receive dexmedetomidine (group C). Patients in group D received a loading dose of dexmedetomidine 0.5 mu g/kg before anesthesia induction and a continuous infusion at 0.5 mu g<middle dot>kg(- 1)<middle dot>h(- 1) until the end of the surgery. Dexmedetomidine was not administered in group C. The primary outcome was the NfL concentration on postoperative day 1. The concentrations of procalcitonin (PCT), serum amyloid A (SAA), and high-sensitivity C-reactive protein (hs-CRP) were detected preoperatively and on postoperative day 1. In addition, the numerical rating scale (NRS) and quality of recovery-40 (QoR-40) scores were evaluated.<br /> Results: A total of 38 patients in group D and 37 in group C were included in the analysis. No differences were observed between the groups in terms of the plasma concentration of NfL preoperatively and on postoperative day 1 (11.17 [8.86, 13.93] vs 13.15 [10.76, 15.56] pg/mL, P > 0.05; 16.70 [12.23, 21.15] vs 19.48 [15.25, 22.85] pg/mL, P > 0.05, respectively). However, the postoperative plasma NfL concentration was significantly higher than the preoperative value in both groups (both P < 0.001). The groups exhibited no differences in PCT, SAA, hs-CRP, NRS, and QoR-40 (all P > 0.05).<br /> Conclusion: Intraoperative administration of dexmedetomidine at a conventional dose does not appear to significantly reduce the increase in postoperative plasma NfL concentration in elderly patients undergoing thoracoscopic surgery. This finding suggests that the neuroprotective effect of dexmedetomidine at a conventional dose was not obvious during general anesthesia.