QUANTIFICATION OF TRAUMATIC HEMOMEDIASTINUM USING TRANSESOPHAGEAL ECHOCARDIOGRAPHY - IMPACT ON PATIENT-MANAGEMENT

Study objectives: To determine whether the quantitative evaluation of hemomediastinum using transesophageal echocardiography (TEE) is predic tive of the presence of a traumatic disruption of the thoracic aorta ( TDA) or its branches in patients who have sustained severe blunt chest trauma. Design: Retrospective study. Setting: ICU of a tertiary refer ral teaching hospital. Patients: Forty-one patients sustaining severe blunt chest trauma (32 men, nine women; mean age, 43+/-16 years; mean Injury Severity Score, 39+/-22) who underwent a TEE study were divided into two groups, patients with (group TDA+, n=15) or without (group T DA-, n=26) major vascular injury diagnosed using an alternative method such as aortography, surgery, or necropsy. The control group included 41 age- and sex-matched patients with an unremarkable TEE study perfo rmed to rule out an intracardiac source of emboli. Interventions: The presence of hemomediastinum was quantitatively assessed by measuring t he distances between the esophageal scope and anteromedial aortic wall (distance 1), and between the posterolateral aortic wall and left vis ceral pleura (distance 2) at the level of the aortic isthmus. An obser ver who was unaware of both medical history and final diagnosis measur ed. the distances. Measurements and results: In group TDA+, TEE demons trated aortic injuries in 13 patients, revealed an isolated hemomedias tinum in one patient (ruptured intercostal arteries), and was unremark able in the remaining patient, who sustained a disrupted right subclav ian artery. No associated major vessel injuries mere diagnosed in the group TDA-(normaI aortograms). When compared to the control group, mea n distances were greater in patients with chest trauma (distance 1=5.5 +/-4.4 mm vs 2.7+/-0.8 mm, p=0.001; distance 2=3.8+/-5.0 mm vs 1.2+/-0 .3 mm, p=0.02). The corresponding distances were even greater in group TDA+ when compared with group TDA-(distance 1=8.6+/-5.9 mm vs 3.7+/-1 .5 mm, and distance 2=7.1+/-7.0 mm vs 2.0+/-1.7; for both differences, p<0.01). A threshold value of 5.5 mm for distance 1 or 6.6 mm for dis tance 2 had a sensitivity of 80%, a specificity of 92%, a positive and negative predictive value of 86% and 89%, respectively, for the diagn osis of underlying major vascular injury. Conclusions: TEE allows quan titative assessment of traumatic hemomediastinum. The presence of a la rge hemomediastinum requires further evaluation by aortography, even i f the thoracic aorta appears normaI during the TEE examination, in ord er to rule out an underlying major vascular injury which may be outsid e the field of view of the echocardiographer.