Mini-Cog to Predict Postoperative Delirium in Patients Who Underwent Transurethral Resection of Bladder Tumor While Awake

OBJECTIVE: In the postoperative management of transurethral resection of bladder tumor, attention should be paid to the appearance of delirium. Recently, the mini-cognitive assessment instrument (Mini-Cog) has been validated as a screening tool for cognitive impairment. We assessed whether positive preoperative cognitive impairment screening by Mini-Cog is associated with the occurrence of postoperative delirium. MATERIAL AND METHODS: In this study, consecutive patients who underwent transurethral resection of bladder tumor while awake and were cognitively screened preoperatively using the Mini-Cog test at our institution were retrospectively analyzed. The relationship between the Mini-Cog test and clinical variables was examined. Univariate and multivariate analyses were carried out to determine the risk factors for the occurrence of postoperative delirium. RESULTS: Of the 193 included patients, 37 (19%) patients had probable cognitive impairment (Mini-Cog scores < 3). There were significant differences in patients’ age (P < .001), Eastern Cooperative Oncology Group-physical status (P = .01), decline in instrumental activities of daily living from baseline (P = .03), preoperative diagnosis of dementia (P < .001), and use of benzodiazepine (P = .03) between the Mini-Cog score ≥ 3 group and the Mini-Cog score < 3 group. Multivariate analysis demonstrated that a Mini-Cog score < 3 (odds ratio = 6.8, P < .001) and instrumental activities of daily living decline (odds ratio = 3.0, P = .02) were independent risk factors for the occurrence of postoperative delirium. CONCLUSION: Screening of patients for cognitive function using the Mini-Cog test before transurethral resection of bladder tumor may allow for better identification of patients at risk of postoperative delirium.