Effects of propranolol pretreatment on cerebral blood flow, oxygen uptake and catecholamines during metabolic acidosis following E. coli endotoxin in dogs

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

PURPOSE

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

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Beta-Blocker Use is Associated With Improved Outcomes in Adult Trauma Patients

BACKGROUND

Beta-adrenoreceptor blocker (beta-blocker) therapy may improve outcomes in surgical patients by decreasing cardiac oxygen consumption and hypermetabolism. Because beta-blockers can lower the systemic blood pressure and cerebral perfusion pressure, there is concern regarding their use in patients with head injury. However, beta-blockers may protect beta-receptor rich brain cells by attenuating cerebral oxygen consumption and metabolism. We hypothesized that beta-blockers are safe in trauma patients, even if they have suffered a significant head injury.

METHODS

Using pharmacy and trauma registry data of a Level I trauma center, we identified a cohort of trauma patients who received beta-blockers during their hospital stay (beta-cohort). Trauma admissions who did not receive beta-blockers were in the control cohort. beta-blocker status, in combination with other variables associated with mortality, were placed in a stepwise multivariate logistic regression to identify independent predictors of fatal outcome.

RESULTS

In all, 303 (7%) of 4,117 trauma patients received beta-blockers. In the beta-cohort, 45% of patients were on beta-blockers preinjury. The most common reason to initiate beta-blocker therapy was blood pressure (60%) and heart rate (20%) control. The overall mortality rate was 5.6% and head injury was considered to be the major cause of death. After adjusting for age, Injury Severity Scale score, blood pressure, Glasgow Coma Scale score, respiratory status, and mechanism of injury, the odds ratio for fatal outcome was 0.3 (p < 0.001) for beta-cohort as compared with control. Decreased risk of fatal outcome was more pronounced in patients with a significant head injury.

CONCLUSIONS

beta-blocker therapy is safe and may be beneficial in selected trauma patients with or without head injury. Further studies looking at beta-blocker therapy in trauma patients and their effect on cerebral metabolism are warranted.