The relationship between postoperative delirium and plasma amyloid beta oligomer.

Postoperative delirium (POD) is a frequent complication in older people undergoing general anesthesia surgery. We investigated the potential link between Alzheimer's disease and POD by comparing plasma amyloid-beta oligomer levels (measured using the multimer detection system, MDS-OAβ) in patients who developed POD after general anesthesia surgery with those who did not. A total of 104 eligible participants were screened daily for delirium for three days postoperatively. After propensity score matching based on the ApoE4 allele, the final analysis included 31 patients with POD and 31 without POD. In the ICU, patients with delirium underwent immediate assessment with the Korean version of the Delirium Rating Scale-98 (K-DRS-98) and plasma MDS-OAβ levels. The control group (those without POD) received the same tests on the third postoperative day. Patients with POD had significantly higher MDS-OAβ values compared to those without POD. Within the POD group, MDS-OAβ values positively correlated with K-DRS-98 scores (both severity and total scores). These findings suggest an association between POD in older people undergoing general anesthesia surgery and elevated plasma amyloid oligomer levels. To definitively establish causality, further prospective studies are necessary.