Role of chest ultrasound in the diagnosis of pulmonary embolism: a cohort study

Background Pulmonary embolism (PE) is a common and usually fatal condition that is commonly misdiagnosed and consequently ignored. Lung ultrasonography is quickly becoming a valuable tool in the ER and ICU for assisting in emergency decisions. Methods One hundred fourteen patients with moderate/high probability of PE in the Critical Care Department meeting the inclusion/exclusion criteria were enrolled in the study. A detailed medical history and a full physical examination involving vital signs, transthoracic ultrasound, CT pulmonary angiography (CTPA), and echocardiography were done for the eligible participants. The goal of this study was to evaluate the diagnostic role of transthoracic ultrasound (TUS) in PE and to compare its specificity and sensitivity with CT pulmonary angiography. Multivariate logistic regression analysis was performed. Results Within the 75 patients with confirmed PE based on CTPA, 30 had LUS findings of confirmed PE (40%), and 45 had LUS findings not consistent with confirmed PE (60%). Within the 39 patients with no PE based on CTPA, all patients had LUS findings of non-confirmed PE (100%), and no patients had LUS findings of confirmed PE (0%). The diagnosis of pulmonary embolism based on confirmed LUS signs had sensitivity and specificity of 40% and 100% respectively with 100% positive predictive value and 46.4% negative predictive value. Conclusion Positive TUS findings with moderate/high suspicion for PE may prove a valuable tool in the diagnosis of PE at the bedside, especially in the emergency setting, but a negative TUS study cannot rule out PE with certainty.