Diagnosis: Use of Clinical Probability Algorithms
Section snippets
Initial assessment
The initial assessment of a patient with a clinical picture suggestive of PE requires a careful medical history, physical examination, and in many cases a chest radiograph and electrocardiogram. The medical history should evaluate for risk factors and clinical symptoms of PE. A recent registry has shown that a constellation of 2 symptoms and 1 sign is typical in patients presenting with confirmed PE: chest pain, shortness of breath (SOB), and massive PE defined as shock or syncope.12 The
Clinical probability of PE
Once the assessment is complete, clinicians should assign a pretest probability of PE to decide on the correct test to rule in or rule out PE. Bayes33 theorem states that posttest odds equal the likelihood ratio of the test result multiplied by the pretest odds. The concept is that with a reasonably sensitive and specific test, the lower the pretest probability the more likely will a positive test result be falsely positive and with a high pretest probability the more likely will a negative
Clinical prediction rules
To the authors’ knowledge, several clinical prediction rules have been reported in the literature but only 4 have been validated prospectively. There are multiple differences between these rules, such as the ease of use, the requirements for complementary tests (chest radiography and measurement of blood gases and D dimer), the number of variables included, and the scoring systems used. All rules have limitations.
This review focuses on 4 of the rules that have been widely studied: the Geneva,
Combining clinical prediction rules with diagnostic tests
A negative D-dimer test result combined with a low- or intermediate-probability clinical assessment by clinical prediction rules excludes PE, if the D-dimer level is measured with an assay proved to have a sensitivity greater than 85%.32, 47, 57, 58, 59 When the Wills rule is used, the 3-month risk of VTE is 0% to 0.5% in untreated patients with a negative D-dimer test result and an unlikely46 or a low or intermediate clinical probability37 Similar results have been reported with the Geneva
Summary
An effective and safe approach to the diagnosis of PE requires a clinical probability assessment and the correct diagnostic technique. Clinical probability assessment relies on medical history, careful physical examination, good-quality chest radiographs, and occasionally electrocardiograms. Physicians who are trained or experienced in the diagnosis of PE can decide the clinical probability based on their judgment. Some investigators advocate the use of a gestalt approach rather than the use of
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ACR Appropriateness Criteria® Suspected Pulmonary Embolism: 2022 Update
2022, Journal of the American College of RadiologyCitation Excerpt :This is in keeping with the fact that no advanced imaging is supported for patients included in this clinical scenario [8,12-16]. The literature does not support the use of CT chest with IV contrast for the evaluation of suspected PE for patients with low to intermediate probability and negative D-dimer [8,12-16]. The use of CT for alternate diagnoses is beyond the scope of this document.
ACR Appropriateness Criteria<sup>®</sup> Acute Chest Pain—Suspected Pulmonary Embolism
2017, Journal of the American College of RadiologyCitation Excerpt :It is also of limited value in patients determined to be at high risk of PE by validated clinical criteria. In all other settings, a negative D-dimer test effectively excludes PE or DVT [3-7]. The posterior anterior and lateral chest radiograph is an important initial study in the evaluation of suspected PE.
Ensuring diagnostic accuracy in pediatric emergency medicine
2011, Clinical Pediatric Emergency MedicineCitation Excerpt :It does not, however, address how clinical gestalt may lead to practice variation and outcome differences related to time management and resource utilization. Gandara and Wells25 suggest caution in comparing CPRs and clinical gestalt as CPRs can often be assessed using hard measurements, whereas gestalt is often difficult to assess and teach. In addition, clinicians basing decisions solely on clinical gestalt may lean toward moderate risk stratification and thus have higher investigation rates.
Diagnosis of deep venous thrombosis and pulmonary embolism
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