Computed Tomography Use for Adults With Head Injury: Describing Likely Avoidable Emergency Department Imaging Based on the Canadian CT Head Rule.

BACKGROUND: Millions of head computed tomography (CT) scans are ordered annually, but the extent of avoidable imaging is poorly defined. OBJECTIVES: The objective was to determine the prevalence of likely avoidable CT imaging among adults evaluated for head injury in 14 community emergency departments (EDs) in Southern California. METHODS: We conducted an electronic health record (EHR) database and chart review of adult ED trauma encounters receiving a head CT from 2008 to 2013. The primary outcome was discordance with the Canadian CT Head Rule (CCHR) high-risk criteria; the secondary outcome was use of a neurosurgical intervention in the discordant cohort. We queried systemwide EHRs to identify CCHR discordance using criteria identifiable in discrete data fields. Explicit chart review of a subset of discordant CTs provided estimates of misclassification bias and assessed the low-risk cases who actually received an intervention. RESULTS: Among 27,240 adult trauma head CTs, EHR data classified 11,432 (42.0%) discordant with CCHR recommendation. Subsequent chart review showed that the designation of discordance based on the EHR was inaccurate in 12.2% (95% confidence interval [CI] = 5.6% to 18.8%). Inter-rater reliability for attributing CCHR concordance was 95% (κ = 0.86). Thus, we estimate that 36.8% of trauma head CTs were truly likely avoidable (95% CI = 34.1% to 39.6%). Among the likely avoidable CT group identified by EHR, only 0.1% (n = 13) received a neurosurgical intervention. Chart review showed none of these were actually "missed" by the CCHR, as all 13 were misclassified. CONCLUSION: About one-third of head CTs currently performed on adults with head injury may be avoidable by applying the CCHR. Avoidance of CT in such patients is unlikely to miss any important injuries.

Risk stratifying emergency department patients with acute pulmonary embolism: Does the simplified Pulmonary Embolism Severity Index perform as well as the original?

INTRODUCTION: The Pulmonary Embolism Severity Index (PESI) is a validated prognostic score to estimate the 30-day mortality of emergency department (ED) patients with acute pulmonary embolism (PE). A simplified version (sPESI) was derived but has not been as well studied in the U.S. We sought to validate both indices in a community hospital setting in the U.S. and compare their performance in predicting 30-day all-cause mortality and classification of cases into low-risk and higher-risk categories. MATERIALS AND METHODS: This retrospective cohort study included adults with acute objectively confirmed PE from 1/2013 to 4/2015 across 21 community EDs. We evaluated the misclassification rate of the sPESI compared with the PESI. We assessed accuracy of both indices with regard to 30-day mortality. RESULTS: Among 3006 cases of acute PE, the 30-day all-cause mortality rate was 4.4%. The sPESI performed as well as the PESI in identifying low-risk patients: both had similar sensitivities, negative predictive values, and negative likelihood ratios. The sPESI, however, classified a smaller proportion of patients as low risk than the PESI (27.5% vs. 41.0%), but with similar low-risk mortality rates (<1%). Compared with the PESI, the sPESI overclassified 443 low-risk patients (14.7%) as higher risk, yet their 30-day mortality was 0.7%. The sPESI underclassified 100 higher-risk patients (3.3%) as low risk who also had a low mortality rate (1.0%). CONCLUSIONS: Both indices identified patients with PE who were at low risk for 30-day mortality. The sPESI, however, misclassified a significant number of low-mortality patients as higher risk, which could lead to unnecessary hospitalizations.

Value and limitations of chest pain history in the evaluation of patients with suspected acute coronary syndromes.

CONTEXT: The chest pain history, physical examination, determination of coronary artery disease (CAD) risk factors, and the initial electrocardiogram compose the information immediately available to clinicians to help determine the probability of acute myocardial infarction (AMI) or acute coronary syndrome (ACS) in patients with chest pain. However, conflicting data exist about the usefulness of the chest pain history and which components are most useful. OBJECTIVE: To identify the elements of the chest pain history that may be most helpful to the clinician in identifying ACS in patients presenting with chest pain. EVIDENCE ACQUISITION: MEDLINE and Ovid were searched from 1970 to September 2005 by using specific key words and Medical Subject Heading terms. Reference lists of these articles and current cardiology textbooks were also consulted. EVIDENCE SYNTHESIS: Certain chest pain characteristics decrease the likelihood of ACS or AMI, namely, pain that is stabbing, pleuritic, positional, or reproducible by palpation (likelihood ratios [LRs] 0.2-0.3). Conversely, chest pain that radiates to one shoulder or both shoulders or arms or is precipitated by exertion is associated with LRs (2.3-4.7) that increase the likelihood of ACS. The chest pain history itself has not proven to be a powerful enough predictive tool to obviate the need for at least some diagnostic testing. Combinations of elements of the chest pain history with other initially available information, such as a history of CAD, have identified certain groups that may be safe for discharge without further evaluation, but further study is needed before such a recommendation can be considered reasonable. CONCLUSION: Although certain elements of the chest pain history are associated with increased or decreased likelihoods of a diagnosis of ACS or AMI, none of them alone or in combination identify a group of patients that can be safely discharged without further diagnostic testing.

Hypoattenuation on CT angiographic source images predicts risk of intracerebral hemorrhage and outcome after intra-arterial reperfusion therapy.

BACKGROUND AND PURPOSE: Symptomatic hemorrhagic transformation (HT) is a significant complication of intravenous and catheter-based reperfusion. We hypothesized that the degree of vascular insufficiency, reflected as hypoattenuation on initial CT angiography (CTA) axial source images, is predictive of HT risk in stroke patients receiving intra-arterial reperfusion therapy. METHODS: We examined initial CTA source images and follow-up CT scans in 32 consecutive patients. Regions of interest were semiautomatically segmented and reviewed. Mean intensity was determined in the region of maximal hypoattenuation and in normal contralateral tissue, and the arithmetic difference (deltaHU) calculated. Receiver operator characteristic (ROC) curves and cross-validation were used to identify threshold deltaHU values. RESULTS: Thirteen patients had HT on follow-up CT (seven with parenchymal hematoma, six with hemorrhagic infarction). Patients with and those without HT did not differ in age, blood glucose level, lesion volume, or time to treatment or recanalization, though the former had a greater mean deltaHU (9.0 vs 6.3, P = .006). The ROC threshold at deltaHU > or = 8.1 was 69% sensitive and 90% specific for patients who developed HT (odds ratio = 19.1; 95% confidence interval: 2.9, 125; P = .002) and was predictive of poor clinical outcome (modified Rankin scale score > 2, P = .03). Neither HT in general nor parenchymal hematoma subtype was associated with poor outcome. CONCLUSION: The degree of hypoattenuation on initial CTA source images is a risk factor for HT and poor clinical outcome after intra-arterial reperfusion therapy. Prospective validation of this relationship in large populations may permit feasible real-time risk stratification.