A comparative study of postoperative cognitive dysfunction in elderly patients undergoing hip surgery after general anaesthesia and combined spinal and epidural anaesthesia

Background Post-operative cognitive dysfunction (POCD) is the subtle cerebral complication temporally seen following surgery. Objectives: To compare the influence of general anesthesia (GA) and of combined spinal-epidural anesthesia (CSEA) upon the early post-operative neurocognitive outcome in elderly (60-70 years) subjects undergoing hip surgery. To measure the impacts of preoperatively hospital stay on POCD. Methods: Total 60, patients were recruited in a prospective, randomized, parallel-group study. They were enrolled and randomized to receive either GA (N= 30) or CSEA (N = 30). All of them were evaluated on the Mini Mental State Examination (MMSE) for their cognitive function and Clock Drawing Test (CDT) for visuospatial function prior to the surgery. The operated patients were re-evaluated 3 days after the surgery on same scales. The data collected were analyzed to assess statistical significance. Results: We observed no statistically significant difference in cognitive and visuospatial function in both the group pre-operatively, which were comparable with respect to age, sex. We found significant cognitive impairment in patients exposed with GA postoperatively 23.33% whereas in CSEA only 6.66%. Visuospatial function was also significantly affected by GA (26.66%) in comparison to CSEA (13.33%). Duration of preoperative hospital stay didn’t affect the neurocongitive functions postoperatively. Conclusions: We observed a positive difference in cognitive outcome with CSEA as compared to GA. Certain aspects of the cognition were affected to a greater extent like visuospatial functioning with exposure to GA undergoing hip surgery. Keywords: Postoperative Cognitive Dysfunction, Cognitive Impairment, Visuospatial Function, Mini Mental State Examination, Clock Drawing Test