Postoperative delirium is a geriatric syndrome that manifests as changes in cognition, attention, and levels of consciousness after surgery. It occurs in up to 50% of patients after major surgery and is associated with adverse outcomes, including increased hospital length of stay, higher cost of care, higher rates of institutionalization after discharge, and higher rates of readmission. Furthermore, it is associated with functional decline and cognitive impairments after surgery. As the age and medical complexity of our surgical population increases, practitioners need the skills to identify and prevent delirium in this high-risk population. Because delirium is a common and consequential postoperative complication, there has been an abundance of recent research focused on delirium, conducted by clinicians from a variety of specialties. There have also been several reviews and recommendation statements; however, these have not been based on robust evidence. The Sixth Perioperative Quality Initiative (POQI-6) consensus conference brought together a team of multidisciplinary experts to formally survey and evaluate the literature on postoperative delirium prevention and provide evidence-based recommendations using an iterative Delphi process and Grading of Recommendations Assessment, Development and Evaluation (GRADE) Criteria for evaluating biomedical literature.

Background Postoperative cognitive dysfunction (POCD) is a significant cause of morbidity after noncardiac surgery. Identified risk factors are largely limited to demographic characteristics. We hypothesized that POCD was associated with Apolipoprotein E4 (APOE4) genotype and plasma biomarkers of brain injury and inflammation. Methods 394 patients over age 55 undergoing major elective noncardiac surgery were enrolled in this prospective observational study. Apolipoprotein E genotyping was performed at baseline. Plasma was collected at baseline, end of surgery, 4.5, 24, and 48-h postoperatively. Six protein biomarkers were assayed (B-type natriuretic peptide, C-reactive protein, D-dimer, matrix metalloproteinase-9, neuron specific enolase, S-100B). Neurocognitive testing was conducted at baseline, 6 weeks, and 1 yr after surgery; scores were subjected to factor analysis. The association of APOE4 and biomarkers with POCD was tested using multivariable regression modeling. Results 350 patients (89%) completed 6-week neurocognitive testing. POCD occurred in 54.3% of participants at 6 weeks and 46.1% at 1 yr. There was no difference in POCD between patients with or without the APOE4 allele (56.6 vs. 52.6%; p = 0.58). The continuous cognitive change score (mean ± SD) was similar between groups (APOE4: 0.05 ± 0.27 vs. non-APOE4: 0.07 ± 0.28; p = 0.53). 291 subjects (74%) completed testing at 1 yr. POCD occurred in 45.9% of APOE4 subjects versus 46.3% of non-APOE4 subjects (p = 0.95). The cognitive score was again similar (APOE4: 0.08 ± 0.27 vs. non-APOE4: 0.05 ± 0.25; p = 0.39). Biomarker levels were not associated with APOE4 genotype or cognition at 6 weeks or 1 yr. Conclusion Cognitive decline after major noncardiac surgery is not associated with APOE4 genotype or plasma biomarker levels.

Background Postoperative delirium is associated with increased morbidity and mortality. Pre-existing cognitive impairment and depression have been frequently cited as important risk factors for this complication. This prospective cohort study was designed to determine if individuals who perform poorly on preoperative cognitive tests and/or exhibited depressive symptoms would be at high risk for the development of postoperative delirium. Methods One hundred nondemented patients, 50 years and older, scheduled for major, elective noncardiac surgery completed a preoperative test battery that included measures of global cognition, executive function and symptoms of depression. Known preoperative risk factors for delirium were collected and examined with the results of the preoperative test battery to determine the independent predictors of delirium. Results The overall incidence of delirium was 16% and was associated with increased hospital length of stay (p<0.05) and an increased incidence of postoperative complications (p<0.01). Delirious subjects did not differ from their non-delirious cohorts with regard to their preoperative global cognitive function, preexisting medical comorbidities, age, anesthetic management or history of alcohol use. Preoperative executive scores (p<0.001) and depression (p<0.001), as measured by the Trail Making B test and Geriatric Depression Scale Short Form, respectively, were found to be independent predictors of postoperative delirium. Conclusions Low preoperative executive scores and depressive symptoms independently predict postoperative delirium in older individuals. A rapid, simple test combination including tests of executive function and depression could improve physicians’ ability to recognize patients who might benefit from a perioperative intervention strategy to prevent postoperative delirium.