Emergency Evaluation for Pulmonary Embolism, Part 2: Diagnostic Approach.

BACKGROUND In part 1 of this two-part review, we discussed which risk factors, historical features, and physical findings increase risk for pulmonary embolism (PE) in symptomatic emergency department (ED) patients. OBJECTIVES Use published evidence to describe criteria that a reasonable and prudent clinician can use to initiate and guide the process of excluding and diagnosing PE. DISCUSSION The careful and diligent emergency physician can use clinical criteria to safely obviate a formal evaluation of PE, including the use of gestalt reasoning and the pulmonary embolism rule-out criteria (PERC rule, Table 2, part 1). We present published clinical and radiographic features of patients with PE who eluded diagnosis in the ED. D-dimer can be used to exclude PE in many patients, and employing age-based adjustments to the threshold to define an abnormal value can further reduce patient exposure to pulmonary vascular imaging. Moreover, we discuss benefits, limitations, and potential harms of computed tomographic pulmonary vascular imaging relevant to patients and the practice of emergency care. We present algorithms to guide exclusion and diagnosis of PE in patients with suspected PE, including those who are pregnant. CONCLUSIONS Reasonable and prudent emergency clinicians can exclude PE in symptomatic ED patients on clinical grounds alone in many patients, and many more can have PE ruled out by use of the D-dimer.