Postoperative cognitive dysfunction: effects of previous pathology (684.7)

Abstract

Surgery patients may experience postoperative cognitive dysfunction (POCD), potentially depending on age and pre‐operative health status. The study objective was to research the effect of prior infection on POCD in aged rats.Cognitive function after abdominal surgery was compared between healthy aged (AH, 18 months) and aged rats that had recovered from an active mycoplasma infection (AI). Healthy young rats (YH, 3 months) and un‐operated rats served as control. Cognition was assessed 10 ‐ 14 days post‐surgery in the novel object ( NO) and location (NL) test and the Morris water maze (MWM).Cognitive performance of AH was comparable to YH. In these groups surgery only led to a decline in spatial memory. AI showed impaired spatial learning and memory and impaired cognitive flexibility compared to YH, which was further impaired following surgery. Additionally, surgery led to impaired object recognition in AI. Velocity in the MWM did not differ significantly between groups.Age in itself did not lead to cognitive impairment. In healthy young and aged rats abdominal surgery only impaired spatial, hippocampal dependent, cognition. Prior infection however caused cognitive impairment and more generalized and severe POCD in aged rats, indicating that patients with a history of infection may be more prone to develop POCD. Analysis of (neuro)inflammatory markers may provide insight in the influence of prior infection on POCD.