Postoperative cognitive dysfunction and the possible underlying neurodegenerative effect of anaesthesia

Introduction: There is alarming evidence about the involvement of general anaesthesia in the development of postoperative cognitive dysfunction. Aim: To clarify the impact of general anaesthesia on cognitive function and to study the possible effect of general anaesthesia on serum S100B, the marker of neuronal degeneration. Methods: This is a prospective randomised controlled study carried out on 50 patients undergoing elective laparoscopic cholecystectomy under conventional general anaesthesia. Cognitive assessment for selected patients was done preoperative and 1 week postoperative using Paired Associate Learning test (PALT) for assessment of verbal memory and Benton Visual Retention test (BVRT) for assessment of visual memory. Quantitative determination of serum S100B was done for all patients in the basal sample and postoperative sample by applying an enzyme- linked immunoabsorbent assay technique on am automated ELISA platform. Results: Regarding cognitive tests, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (p-value = .012). There was also a statistically significant difference between the mean value of preoperative BVRT and postoperative BVRT (p-value = .011). Regarding S100B, there was a statistically significant difference between preoperative and postoperative serum level (p-value = .002). There was also a statistically significant negative correlation between postoperative S100B serum level and the postoperative scores of both PALT and BVRT. Conclusion: General anaesthesia is incriminated in the development of postoperative verbal and visual memory impairment and in the postoperative increase in serum S100B, the markers of neuronal degeneration.