Perioperative Risk Factors for Postoperative Delirium in Non-dementia Older Patients after Non-cardiac Surgery and Anesthesia: A Prospective Study

Abstract

Background: To investigate the incidence and perioperative risk factors for postoperative delirium (POD) in non-dementia older patients who underwent anesthesia for non-cardiac surgery.

Methods: This prospective cohort study was conducted on 195 non-dementia older patients, aged 60 years or older, who were hospitalized after non-cardiac surgery and anesthesia. The Confusion Assessment Method for the Intensive Care Unit was used to evaluate the occurrence of POD. Incidence of POD was reported. We conducted univariate and multivariate logistic regression to identify the risk factors associated with POD.

Results: A total of 195 patients were enrolled; 172 completed the study. POD occurred in seven patients within three days after anesthesia, which is a 4.1% incidence of POD. Multivariate logistic analysis showed arrhythmia, coagulopathy, urinary comorbidity, minimum intraoperative heart rate, and minimum post-anesthesia care unit (PACU) pain score as independent risk factors for POD. A minimum PACU pain score >1 is the optimum cutoff pain score for developing POD, with a sensitivity of 85.7% and a specificity of 69.1%. The postoperative complication rate and in-hospital mortality were significantly higher for patients with POD compared to those without POD.

Conclusion: The incidence of POD in the study population is 4.1%. Arrhythmia, coagulopathy, urinary comorbidity, minimum intraoperative heart rate, and minimum PACU pain score were independent risk factors for POD. The minimum PACU pain score is the strongest independent risk factor of POD. POD is associated with increased postoperative complications and in-hospital mortality rates in non-dementia older patients.

Keywords: Anesthesia; Older adults; Postoperative delirium; Risk factors.

Fig. 1.

Flow diagram of patient enrollment.

Fig. 2.

Receiver operating characteristic curve of delirium patients’ minimum PACU pain score classification. PACU, post-anesthesia care unit; AUC, area under the curve; CI, confidence interval.