Correlation between olfactory and post-operative cognitive dysfunction of the elderly orthopedic surgery patients in the perianesthesia

Abstract

Objective To investigate the change of olfactory and cognitive function at the perianesthesia of elderly orthopedic surgery patients, and analyze the correlation between them. Methods Thirty elderly orthopedic surgery patients in the anesthesia group who were scheduled for orthopaedic surgery. They were also tested with the Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory assessment in the day before anesthesia, 3nd and 7th day post-anesthesia. The cognitive function of each case was assessed using a battery of neuropsychological tests including Mini-Mental State Examination(MMSE), Hopkins Verbal Learning Test-Revised (HVLT-R), Trail Making Test (TMT), Stroop Color Word Test (SCWT), Digit-Symbol Coding Test (DSCT) and Verbal Fluency Test(VFT). A total of 30 healthy volunteers were recruited under the same inclusion and exclusion criteria, as the control group. Neuropsychological tests were performed to the control group at the same time period as in patients group. Results Compared with the control group, the olfactory identification score was lower in the anesthesia group on 3rd and 7th post-anesthesia day respectively, the difference is statistically significant(P<0.05). On 3rd post-anesthesia day, the scores of MMSE, short-term retention, delayed retention were lower, the scores of the TMT, SCWT were higher(P<0.05). On 7th post-anesthesia day, the scores of short-term retention were lower and the TMT were higher(P<0.05). Linear correlation analysis showed that the different values of olfactory identification score were correlated positively with the different values of short-term retention and delayed retention on 3rd and 7th post-anesthesia day. Conclusions The olfactory dysfunction mainly presented with the decrease of the olfactory identification score of elderly orthopedic surgery patients in the peri-anesthesia. The cognitive dysfunction mainly presented with the decrease of short-term retention, delayed retention and the ability of concentrating. The olfactory dysfunction was positively correlated with the post-anesthesia cognitive dysfunction. Key words: Aged; Orthopedics surgery; Perianesthesia; Olfactory function; Post-operative cognitive dysfunction