Bottom line: Compared with warfarin therapy, apixaban is more effective and safer for stroke prevention in patients with atrial fibrillation.
Citation: Granger CB, Alexander JH, McMurray JJ, et al. Apixaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 2011;365:981-992.
Ultrasonography Is Useful in Diagnosis of Pneumothorax
Clinical question: Is transthoracic ultrasonography a useful tool to diagnose pneumothorax?
Background: CT is the diagnostic gold standard for pneumothorax, but it is associated with radiation exposure and requires patient transport. Chest radiograph is easy to perform but may be too insensitive for adequate diagnosis. Ultrasonography’s diagnostic performance for detecting pneumothorax needs further evaluation.
Study design: Systematic review and meta-analysis.
Setting: Critically ill, trauma, or post-biopsy patients were identified in each of the studies.
Synopsis: The meta-analysis of 20 eligible studies found a pooled sensitivity of ultrasound for the detection of pneumothorax of 0.88 (95% CI: 0.85 to 0.91) and specificity of 0.99 (0.98 to 0.99) compared with sensitivity of 0.52 (0.49 to 0.55) and specificity of 1.00 (1.00 to 1.00) for chest radiograph. Although the overall ROC curve was not significantly different between these modalities, the accuracy of ultrasonography was highly dependent on the skill of the operator.
Bottom line: When performed by a skilled operator, transthoracic ultrasonography is as specific, and more sensitive, than chest radiograph in diagnosing pneumothorax.
Citation: Ding W, Shen Y, Yang J, He X, Zhang M. Diagnosis of pneumothorax by radiography and ultrasonography: a meta-analysis. Chest. 2011;140:859-866.
Risk Prediction for Hospital Readmission Remains Challenging
Clinical question: Can readmission risk assessment be used to identify which patients would benefit most from care-transition interventions, or to risk-adjust readmission rates for hospital comparison?
Background: Multiple models to predict hospital readmission have been described and validated. Identifying patients at high risk for readmission could allow for customized care-transition interventions, or could be used to risk-adjust readmission rates to compare publicly reported rates by hospital.
Study design: Systematic review with qualitative synthesis of results.
Setting: Thirty studies (23 from the U.S.) tested 26 unique readmission models.
Synopsis: Each model had been tested in both a derivation and validation cohort. Fourteen models (nine from the U.S.), using retrospective administrative data to compare risk-adjusted rates between hospitals, had poor discriminative capacity (c statistic range: 0.55 to 0.65). Seven models could be used to identify high-risk patients early in the hospitalization (c statistic range: 0.56 to 0.72) and five could be used to identify high-risk patients at discharge (c statistic range: 0.68 to 0.83), but these also had poor to moderate discriminative capacity. Multiple variables were considered in each of the models; most incorporated medical comorbidities and prior use of healthcare services.
Bottom line: Current readmission risk prediction models do not perform adequately for comparative or clinical purposes.
Citation: Kansagara D, Englander H, Salanitro A, et. al. Risk prediction models for hospital readmission: a systematic review. JAMA. 2011;306:1688-1698.
Intravenous Fluids for Acute Pancreatitis: More May Be Less
Clinical question: What is the optimal volume of fluid administration for treatment of acute pancreatitis?
Background: Current guidelines for management of acute pancreatitis emphasize vigorous administration of intravenous fluids to reduce the risk of pancreatic necrosis and organ failure. This recommendation is based upon animal studies, and has not been subjected to clinical evaluation in humans.
Study design: Prospective observational cohort.
Setting: University-affiliated tertiary-care public hospital in Spain.
Synopsis: This study enrolled 247 patients admitted with acute pancreatitis to determine the association between the volume of fluid administered during the first 24 hours and the development of persistent organ failure, pancreatic fluid collection or necrosis, and mortality. The volume and rate of fluid administered were determined by the treating physician. Patients were classified into three groups: those receiving a volume <3.1 L, 3.1 to 4.1 L, or >4.1 L.