Does laparoscopic colorectal surgery result in short and long term post-operative cognitive decline (POCD)?

Abstract Postoperative cognitive decline (POCD) is defined as a new cognitive impairment arising after surgical intervention. There is some concern that prolonged Trendelenburg positioning during laparoscopic colorectal surgery may cause POCD. Patients with POCD may experience prolonged hospitalisation and take longer returning to their normal level of functioning. Cognitive function can be assessed using validated tests including: N Back, Stroop; and Lexical Decision Making Task. Aim To assess percentage of short and long-term POCD following laparoscopic colorectal surgery. Assess the effect of time spent in Trendelenburg position on developing POCD. Methods Patients undergoing laparoscopic colorectal surgery were recruited. Cognitive tests including: 1, 2 and 3 back, lexical decision making task and stroop task were carried out pre-operatively and repeated Day 1, and minimum 3 months post-operatively. For assessment of POCD Day 1, the baseline was subtracted from Day 1 results for each test. This result was then divided by the standard deviation of the control group to give a Z score. A large positive Z score (>1.96) showed a deterioration in cognitive function from baseline for accuracy, and a large negative Z score (> -1.96) for response time. An individual Z score of 1.96 or more was defined as cognitive dysfunction. Results Forty-six patients were recruited (26 males, 24 female), mean age 66 years (SD± 5.18). Of which 55% had POCD on Day 1; and 37 patients completed long-term follow up of which 32% had POCD. Conclusion Our study does show a significant number of patients develop both long and short term POCD following laparoscopic colorectal surgery.