No abstract

Background: Clinicians in outpatient clinics and emergency departments desire an accurate quantitative Ddimer assay. The study objective was to evaluate the diagnostic performance characteristics of the latex turbidimetric D-dimer test in the diagnosis of pulmonary embolism (PE) in the emergency department population. Methods: We conducted a search of MEDLINE, EM-BASE, and bibliographies of previous systematic reviews with no language restriction. Experts in the field of PE research were contacted to identify unpublished studies. Prospective investigations involving predominately outpatient populations with suspected PE that used a turbidimetric D-dimer test were included. Two authors extracted data independently and assessed study quality based on the composition of the patient spectrum and the reference standard used. Consensus was reached by conference. The analysis was based on a summary ROC curve and combining sensitivity and specificity independently across studies using a random-effects model. Results: The search yielded 264 publications and 2 unpublished studies. Nine studies met the inclusion criteria and provided a sample of 1901 individuals. Eight of the nine studies were homogeneous in terms of both sensitivity and specificity. One study had similar sensitivity but higher specificity. Combining the studies yielded an overall sensitivity of 0.93 (95% confidence interval, 0.89 -0.96) and an overall specificity of 0.51 (95% confidence interval, 0.42-0.59).

Objective: To evaluate the utility of a modified calculation of the alveolar dead space fraction (Vd/Vt), combined with plasma D-dimers, to aid in the exclusion of acute pulmonary embolism (PE). Methods: A prospective comparison of screening modalities was performed in a metropolitan teaching ED. Ambulatory patients evaluated for PE underwent simultaneous end-tidal CO, and arterial blood gas determinations, as well as venous latex-agglutination D-dimer quantification. The modified Bohr equation was used to calculate Vd/Vt as an index of alveolar dead space. Acute PE was diagnosed or excluded using appropriate combinations of clinical suspicion, ventilation-perfusion lung scanning, lower-extremity venous Doppler ultrasonography, pulmonary angiography, and comprehensive follow-up. Results: Of 170 subjects studied, PE was confirmed (PE+) in 26 (15%) and excluded (PE-) in 144 (85%). In the PE+ group, Vd/Vt was 0.31 & 0.13 (mean 2 SD), and in the PE-group, Vd/Vt was 0.06 t-0.10 (p c 0.05, t-test). Regarding false-negative rates, Vd/Vt was normal (i.e., c0.2) in 3/26 PE+ patients and D-dimer concentrations were normal (~0 . 5 pg/L) in 4/26 patients in the PE+ group. The combination of a normal Vd/Vt and D-dimer concentration was 100% sensitive (95% CI = 88-100%) in excluding PE. Falsepositive testing (either test positive) occurred in 49/14 subjects (specificity 65%, 95% CI = 52-73%). The age-adjusted alveolar-arterial O2 gradient was 33 5 38 torr in the PE+ group vs 13 2 37 torr in the PEgroup (p = 0.1 1). Conclusions: In ambulatory patients, the finding of Vd/Vt ~0 . 2 and D-dimers c0.5 pg/L lowers the probability of acute PE.

For patients with positive MRI at the time of their initial neurologic event, both gadolinium-enhancing lesions and the Barkhof criteria are predictors for development of CDMS over a short interval. However, these results, based on a combined CDMS/MRI outcome, suggest that the majority of these patients are already in the earliest stages of MS, regardless of whether any further MRI criteria are met.

No abstract

The effect of introducing a structured approach to the diagnosis of pulmonary embolism in UK emergency departments has been complex. Unlike our US and Australasian counterparts, it can take several days to complete the pulmonary embolism investigative pathway, as delays for ventilation-perfusion and computed tomography (CT) scans are common. As in the US [1], a larger proportion of emergency department patients now undergo pulmonary embolism rule-out strategies. During pulmonary embolism exclusion patients can be admitted to hospital unnecessarily. Furthermore, patient care is passed from the emergency department to the admitting medical physician. On occasion, the admitting specialties disagree that exclusion of pulmonary embolism is necessary: for example, in the young well patient with isolated pleuritic chest pain. The PERC rule [2] provides a standardized approach to assessing such patients prior to commencing a rule-out strategy.The Manchester Investigation of Pulmonary Embolism Diagnosis study (MIOPED study) is a prospective cohort study which recruited 425 patients with pleuritic chest pain. Between February 2002 and May 2003 patients presenting to Manchester Royal Infirmary's emergency department with pleuritic chest pain were consented and recruited. Exclusion criteria included pneumothorax, electrocardiogram (ECG) changes of myocardial infarction, ischemia or pericarditis, pregnancy, trauma within 4 weeks, age under 18 and patients previously recruited to the study. Pulmonary embolism was excluded with combined normal IL D-dimer test and low clinical probability, a normal ventilation-perfusion scan or a low probability ventilationperfusion scan with low clinical probability, normal CT

No abstract

Objective: To assess the clinical outcome of patients suspected of pulmonary embolism (PE) following implementation of an emergency department (ED) diagnostic guideline. Methods: A prospective observational study of all patients suspected of PE who presented to the ED during a four-month study period. The authors' modification of the Charlotte criteria recommended D-dimer testing in those younger than 70 years of age with a low clinical suspicion of PE and no unexplained hypoxemia, unilateral leg swelling, recent surgery, hemoptysis, pregnancy, or prolonged duration of symptoms. The primary outcome was the identification of venous thromboembolism during a three-month follow-up period. The negative predictive value of the overall diagnostic strategy and the test characteristics of D-dimer were calculated. Results: A total of 1,207 consecutive patients were evaluated for suspected PE; 71 (5.8%) were diagnosed with venous thromboembolism. One missed case of PE was identified on follow-up, yielding a negative predictive value of 99.9% (95% confidence interval [CI] = 99.5% to 100%). The missed case was a patient who presented with pleuritic chest pain and shortness of breath; a chest radiograph revealed pneumothorax, and the physician decided not to pursue the positive D-dimer result. The patient returned six weeks later with PE. Subgroup analysis of patients having D-dimer performed (n = 677) yields a sensitivity of 0.93 (95% CI = 0.77 to 0.98) and a specificity of 0.74 (95% CI = 0.70 to 0.77). Conclusions: Implementation of a PE diagnostic guideline in a community ED setting is safe and has improved the specificity of the enzyme-linked immunosorbent assay D-dimer test when compared with previous studies. The evaluation of patients suspected of pulmonary embolism (PE) is complex, and numerous diagnostic strategies have been suggested. 1-7 Clinical guidelines or protocols may assist physicians with complicated diagnostic algorithms and improve care by decreasing inappropriate variance in practice style. 8,9 At the same time, algorithms that reduce patient care into a sequence of binary decisions often do injustice to the complexity of medicine. 10 The rationale for a PE rule-out protocol has been described; however, the safety and efficiency of a PE rule-out protocol awaits empiric confirmation. 11,12 Generally, simple innovations spread faster than complicated ones. 13 A prediction rule will be used if it makes clinical sense and is simple. 14 One of the aims of our PE diagnostic guideline was to simplify the complicated algorithms and decision rules that have been proposed. 1 The guideline focus was on pretest probability assessment and the appropriate use of D-dimer testing. 7,8,12 The implementation of a PE rule-out protocol or guideline requires the understanding and approval of physicians at the local level. The emergency physicians at our institution agreed to start with empiric clinical judgment to arrive at a pretest probability for PE and then apply a modification of the Charlotte criteria to assist in diag...