Anesthesia and post-operative delirium in elderly patients undergoing hip fracture surgery

Background.– The prevalence of postoperative delirium (POD) in patients undergoing hip fracture surgery ranges from 15% to 53%. POD is associated with high mortality, cognitive deterioration, and nursing home placement. Among the potential risk factors for POD, anesthesia has been claimed as one of the most important. Here, we evaluate the association between type of anesthesia and POD in elderly patients undergoing hip fracture surgery. Methods.– Retrospective cohort study of 392 patients aged > 65 years admitted to the Orthogeriatric Unit, San Gerardo hospital (Monza, Italy) between 2007 and 2011. Delirium was assessed according to the DSM-IV-TR criteria. A multidimensional geriatric assessment was performed at hospital admission. Patients who did not undergo surgical intervention, those with delirium before surgery and those with incomplete data in the medical records were excluded from this study. A multivariate logistic regression model was used to analyze the association between anesthesia [general vs spinal vs peripheral neural block (PNB), PNB vs general + PNB] and POD, after adjusting for potential confounders, including age, gender, Charlson Comorbidity Index, ASA score, pre-fracture disability in Activities of Daily Living (Katz's ADL Index), and pre-fracture dementia. Results.– The mean (±SD) age was 83 ± 6. The incidence of POD was similar in patients with PNB (37%), with general + PNB (35%), with only general anesthesia (32%) and with spinal anesthesia (20%). After adjusting for covariates, pre-fracture dementia (odds ratio [OR], 5.19; 95% confidence interval: 1.62–3.09; P < 0.001) and pre-fracture disability (OR, 4.53; 95% CI: 1.08–4.01; P < 0.001) were the only variables predicting POD. Conclusion.– The type of anesthesia did not predict POD in elderly patients undergoing hip fracture surgery. Pre-fracture disability and pre-fracture dementia were the only two variables predicting this condition, indirectly suggesting that a multidimensional geriatric assessment can provide anesthesiologists with important information to identify patients at risk for POD.