Perioperative inflammatory response and protein S‐100β concentrations – relationship with post‐operative cognitive dysfunction in elderly patients

Background One major concern in about one third of elder patients after total hip‐replacement surgery is post‐operative cognitive dysfunction ( POCD ). Previous studies have suggested that cognitive impairment is accompanied with changes in serum S‐100β protein ( S‐100β ) and inflammatory markers. Thus, the aim of the current study was to investigate the value of serum S‐100β and interleukin( IL ) ‐1β , IL‐6 , tumour necrosis factor‐α ( TNF‐α ), and C‐reactive protein ( CRP ) in reflecting POCD after total hip‐replacement surgery. Methods Forty‐two elderly patients were enrolled, and 37 patients completed the follow‐up. Serum S‐100β protein and IL‐1β , IL‐6 , TNF‐α , and CRP were determined pre‐operatively, as well as 1 h and 6 h post‐operatively. Neuropsychological tests were performed pre‐operatively, as well as on day 1, 3, and 7 post‐operatively. Results Seventeen (45.9%, 17/37) patients developed POCD 1 day after surgery, and three (8.1%, 3/37) developed POCD 7 days after surgery. [Correction added after publication 7 February 2012: in the preceding sentence (54.1%, 17/37) was corrected to (45.9%, 17/37)]. Patients with POCD 1 day after surgery had significantly higher serum levels of IL‐6 at 6 h (135 ± 32 pg/ml vs. 91 ± 29 pg/ml, P < 0.05) and S‐100β at 1 h (1872 ± 385 pg/ml vs. 1289 ± 143 pg/ml, P < 0.05. No significant post‐operative change was detected in levels of TNF‐α , IL‐1 , or CRP . Conclusion The serum levels of pro‐inflammatory marker IL‐6 and S‐100β protein increased after total hip‐replacement in elderly patients, and such increase may serve as predicting parameters for the occurrence of POCD .