Association between oxidative stress and postoperative delirium in joint replacement using diacron-reactive oxygen metabolites and biological antioxidant potential tests

Abstract Postoperative delirium (POD) is a significant complication of surgery that most severely affects older adults and patients with cognitive impairment. This study investigated the relationship between POD and oxidative stress, hypothesizing that increased oxidative stress, measured using diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP) tests, is associated with the incidence of POD. This prospective cohort study, involving female patients who underwent unilateral or bilateral joint replacement, was conducted at the Osaka University Graduate School of Medicine from June 2022 to July 2023. Blood samples were collected preoperatively and postoperatively to measure oxidative stress markers using the REDOXLIBRA system. The primary endpoint was the association between changes in oxidative stress markers and the occurrence of POD as diagnosed using the Confusion Assessment Method for the Intensive Care Unit and Richmond Agitation–Sedation Scale. Of the 144 patients screened, 60 were eligible, of which 5 developed POD (8.3%). Analysis of oxidative stress markers revealed no significant changes between preoperative and postoperative values of d-ROMs (mean increase + 6.3 ± 54.2 U CARR) and BAP (mean decrease − 37.4 ± 322.9 µM) tests, or BAP/d-ROMs ratio (mean decrease − 0.4 ± 1.7). Further, no significant differences were observed in oxidative stress markers between patients who underwent unilateral and bilateral procedures. However, patients with POD exhibited a significantly higher increase in d-ROMs than those without complications (p = 0.015), whereas changes in BAP and BAP/d-ROM ratios were not statistically significant. Although general oxidative stress markers do not significantly change postoperatively, increased d-ROM levels are associated with POD occurrence, indicating that oxidative stress could be a contributing factor to its development. This study underscores the need for further research into specific oxidative markers that may predict POD and guide the development of targeted interventions to prevent this debilitating condition. Trial registration Name of the registry Association Between Changes in Blood Oxidative Stress and Postoperative Delirium Following Joint Replacement Surgery: A Retrospective Study. Trial registration number 22021. Date of registration 6/29/2022. URL of trial registry record https://bvits.dmi.med.osaka-u.ac.jp/esct/Apply/project.aspx?PROJECT_ID=6987 .