Delirium following vascular surgery: increased incidence with preoperative beta-blocker administration

To determine if there is an association between perioperative administration of beta-blockers and postoperative delirium in patients undergoing vascular surgery.

After Institutional Review Board approval, data were retrospectively collected on patients who underwent vascular surgery in an academic hospital during the period January 2006 to January 2007. Patients with preoperative altered level of consciousness, carotid endarterectomy, or discharge within 24 h of surgery were excluded from the study. Identification of delirium was based on evaluation of the level of consciousness with the NEECHAM Confusion Scale and/or a chart-based instrument for delirium. Multivariable logistic regression analysis was used to identify independent perioperative predictors of postoperative delirium. Beta-blockers were tested for a potential effect.

The incidence of postoperative delirium was 128/582 (22%). Independent predictors included age (OR 1.04, 95% CI [1.02-1.07]), history of cerebrovascular accident/transient ischemic attack (OR 2.64, 95% CI [1.57-4.55]), and depression (OR 3.56, 95% CI [1.53-8.28]). Open aortic reconstruction was associated with an OR of 5.34, 95% CI (2.54-11.2) and amputation with an OR of 4.66, 95% CI (1.96-11.09). Preoperative beta-blocker administration increased the odds of postoperative delirium 2.06 times (95% CI [1.18-3.6]). Statin administration reduced the odds of delirium by 44% (95% CI [0.37-0.88]). The model was reliable (Hosmer-Lemeshow test, P = 0.72) and discriminative (area under the receiver operating characteristic [ROC] curve = 0.729).

Preoperative administration of beta-blockers is associated with an increased risk of postoperative delirium after vascular surgery. Conversely, preoperative statin administration is associated with a lower risk of postoperative delirium. A randomized prospective controlled trial is required to validate these findings.