Pulmonary Embolism (Haemodynamically Unstable)

Pathway

Images

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1		Hampton's Hump Image 1 (Plain Radiograph): There is a peripheral wedge shaped opacity representing pulmonary infarction and atelectasis secondary to a pulmonary embolus (arrow). This radiographic sign is referred to as Hampton's Hump.
2a		Bilateral Pulmonary Embolism Image 2a and 2b (Computed Tomography): Axial and reconstructed images of bilateral pulmonary arterial emboli (arrows)
2b
3		Bilateral Pulmonary Embolism Image 3 (Ventilation Perfusion Scan): The ventilation series demonstrates uniform distribution of tracer throughout both lung fields. The perfusion series demonstrates generalised reduced tracer uptake in the right lung with multiple segmental and subsegmental perfusion defects throughout both lung fields. These findings have a high probability for recent pulmonary embolism.

Teaching Points

Teaching Points

• Suspected PE in the setting of haemodynamic instability is immediately life threatening and requires urgent investigation and treatment
• CT pulmonary angiography (CTPA) is a highly sensitive and specific test which can directly demonstrate PE through filling defects within contrast filled pulmonary arteries down to the segmental level. Although CTPA involves ionising radiation, the urgency of the situation justifies its use as a first line investigation if it is immediately available and if the patient is stable following resuscitation
• ECG-synchronised CTPA provides better assessment of ventricular function
• Haemodynamic measurements should always be recorded during pulmonary angiography to estimate the severity of PE and assist in diagnosing alternative cardiopulmonary disorders
• If the patient remains unstable following resuscitation or if CTPA is not available, bedside transthoracic echocardiography (TTE) is the most useful test. It can demonstrate signs of acute pulmonary hypertension secondary to PE and also assess for cardiac causes of shock
• A negative bedside TTE cannot exclude PE
• Transoesophageal echocardiogram (TOE) may be considered in specific clinical scenarios. Presence of a mobile right heart thrombus often indicates bilateral central pulmonary emboli
• Treatment includes systemic thrombolysis or catheter directed thrombolysis. Alternatively, catheter thromboembolectomy or surgical embolectomy can be considered in patients with contraindications to thrombolysis

References

References

References are graded from Level I to V according to the Oxford Centre for Evidence-Based Medicine, Levels of Evidence. Download the document

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8. Stein PD, Woodard PK, Weg JG, Wakefield TW, Tapson VF, Sostman HD, et al. Diagnostic pathways in acute pulmonary embolism: recommendations of the PIOPED II Investigators. Radiology. 2007;242(1):15-21 (Guideline). View the reference
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10. Coche E, Verschuren F, Keyeux A, Goffette P, Goncette L, Hainaut P, et al. Diagnosis of acute pulmonary embolism in outpatients: comparison of thin-collimation multi-detector row spiral CT and planar ventilation-perfusion scintigraphy. Radiology. 2003;229(3):757-65 (Level III evidence). View the reference
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15. Meinel FG, Nance JW, Jr., Schoepf UJ, Hoffmann VS, Thierfelder KM, Costello P, et al. Predictive Value of Computed Tomography in Acute Pulmonary Embolism: Systematic Review and Meta-analysis. Am J Med. 2015;128(7):747-59.e2 (Level I evidence). View the reference
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