Article: Ghanem MK, Makhlouf HA, Hasan AA, Alkarn AA. Acute pulmonary thromboembolism in emergency room: gray-scale versus color doppler ultrasound evaluation. Clin Respir J. 2018 Feb;12(2):474-482. doi: 10.1111/crj.12547. Epub 2016 Sep 27. PMID: 27608416.

Overview: Acute pulmonary thromboembolism (PE) is frequently underdiagnosed and consequently undertreated. The gold standard for detection of PE is via Computed tomography pulmonary angiography (CTPA). This study, however, is expensive and can sometimes be difficult to obtain in a timely matter. Transthoracic ultrasonography (TUS) is an emerging noninvasive diagnostic technique that may have an important role in diagnosing PE.

Study: 60 Consecutive patients in a tertiary hospital with high suspicion for PE were enrolled in this prospective analytic cross-sectional study. Sonographic examination of the lung and pleura was done by applying the scanner in the intercostal areas where the patient localized pain, followed by evaluation of remaining intercostal spaces in 6 vertical lines. Diagnosis of PE was considered if at least one of more typical pleural-based/subpleural hypoechoic lesions with or without pleural effusion were reported by TUS. Color Doppler was then used to detect infarcted areas showing consolidation with little perfusion. CTPA was then done to assess for the presence of PE

Results: 40 out of 60 patients were found to have PE via CTPA. Of these 40 patients, 33 were found to have PE via TUS. TUS demonstrated a total of 66 lesions with 64 of them showing areas of consolidation with little perfusion. The presence of pleuritic chest pain and hemoptysis were significantly higher in the presence of positive TUS. Of the 7 PE that were missed on TUS, 5 of them were centrally located. The sensitivity, specificity, PPV, NPV and accuracy of gray-scale TUS in patients with clinically suspected PE were 82%,90%,94%,72% and 85% respectively. Color Doppler increased specificity, PPV, and the accuracy of TUS to 95%, 97%, and 87% respectively.

Takeaway: TUS is a reliable diagnostic bedside test for PTE in critically ill and immobile patients. Adding color Doppler to gray-scale TUS will increase the specificity and accuracy of TUS, especially in the diagnosis of peripheral pulmonary infarctions. Patient presenting with pleuritic chest pain or hemoptysis were more likely to have positive TUS findings consistent with PE. TUS is more likely to miss a PE that is centrally located, therefore the implementation of TUS and echocardiography as a two beside test may increase the sensitivity of TUS in the ED.

Post by: Daniel Klein, MS4