Finite Element Analysis of the Mechanism of Traumatic Aortic Rupture (TAR).

As many as 80% of patients with TAR die on the spot while out of those reaching a hospital, 30% would die within 24 hours. Thus, it is essential to better understand and prevent this injury. The exact mechanics of TAR are unknown. Although most researchers approve it as a common-sense deceleration injury, the exact detailed mechanism of TRA still remains unidentified. In this work, a deceleration mechanism of TAR was carried out using finite element analysis (FEA). The FE analysis aimed to predict internal kinematics of the aorta and assist to comprehend the mechanism of aorta injury. The model contains the heart, lungs, thoracic aorta vessel, and rib cage. High-resolution computerized tomography (HR CT scan) was used to provide pictures that were reconstructed by MIMICS software. ANSYS FE simulation was carried out to investigate the behavior of the aorta in the thoracic interior after deceleration occurred during a car crash. The finite element analysis indicated that maximum stress and strain applied to the aorta were from 5.4819e5 to 2.614e6 Pa and 0.21048 to 0.62676, respectively, in the Y-direction when the initial velocity increased from 10 to 25 m/s. Furthermore, in the X-direction when the velocity changed from 15 to 25 m/s, the stress and strain values increased from 5.17771e5 to 2.3128e6 and from 0.22445 to 0.618, respectively.

New-onset, postoperative tachyarrhythmias in critically ill surgical patients.

Tachyarrhythmias in critically ill surgical patients can have varying effects, from minimal consequence to lifetime sequelae. Atrial fibrillation can be common in the post-operative period, often a result of fluctuations in volume status and electrolyte derangements. While there is extensive literature regarding the critically ill medical or cardiac patient, there is less focusing on the critically ill surgical or trauma patient. More specifically, there is minimal regarding tachyarrhythmias in burn patients. The latter population tends to have frequent and wide variations in volume status given initial resuscitation and after major excisions, concomitant with acute blood loss anemia, which can contribute to cardiac disturbances. A literature review was conducted to investigate the incidence and consequences of tachyarrhythmias in critically ill surgical and trauma patients, with a focus on the burn population. While some similarities and conclusions can be drawn between these surgical populations, further inquiry into the unique burn patient is necessary.

Cardiac magnetic resonance imaging in suspected blunt cardiac injury: A prospective, pilot, cohort study.

INTRODUCTION: The aim of this study was to evaluate the incidence and severity of blunt cardiac injury (BCI) as determined by cardiac magnetic resonance imaging (CMR), and to compare this to currently used diagnostic methods in severely injured patients. MATERIALS AND METHODS: We conducted a prospective, pilot cohort study of 42 major trauma patients from July 2013 to Jan 2015. The cohort underwent CMR within 7 days, enrolling 21 patients with evidence of chest injury and an elevated Troponin I compared to 21 patients without chest injury who acted as controls. Major adverse cardiac events (MACE) including ventricular arrhythmia, unexplained hypotension requiring inotropes, or a requirement for cardiac surgery were recorded. RESULTS: 6/21 (28%) patients with chest injuries had abnormal CMR scans, while all 21 control patients had normal scans. CMR abnormalities included myocardial oedema, regional wall motion abnormalities, and myocardial haemorrhage. The left ventricle was the commonest site of injury (5/6), followed by the right ventricle (2/6) and tricuspid valve (1/6). MACE occurred in 5 patients. Sensitivity and specificity values for CMR at predicting MACE were 60% (15-95) and 81% (54-96), which compared favourably with other tests. CONCLUSION: In this pilot trial, CMR was found to give detailed anatomic information of myocardial injury in patients with suspected BCI, and may have a role in the diagnosis and management of patients with suspected BCI.

Imaging in blunt cardiac injury: Computed tomographic findings in cardiac contusion and associated injuries.

BACKGROUND: Blunt cardiac injury (BCI) may manifest as cardiac contusion or, more rarely, as pericardial or myocardial rupture. Computed tomography (CT) is performed in the vast majority of blunt trauma patients, but the imaging features of cardiac contusion are not well described. PURPOSE: To evaluate CT findings and associated injuries in patients with clinically diagnosed BCI. MATERIALS AND METHODS: We identified 42 patients with blunt cardiac injury from our institution's electronic medical record. Clinical parameters, echocardiography results, and laboratory tests were recorded. Two blinded reviewers analyzed chest CTs performed in these patients for myocardial hypoenhancement and associated injuries. RESULTS: CT findings of severe thoracic trauma are commonly present in patients with severe BCI; 82% of patients with ECG, cardiac enzyme, and echocardiographic evidence of BCI had abnormalities of the heart or pericardium on CT; 73% had anterior rib fractures, and 64% had pulmonary contusions. Sternal fractures were only seen in 36% of such patients. However, myocardial hypoenhancement on CT is poorly sensitive for those patients with cardiac contusion: 0% of right ventricular contusions and 22% of left ventricular contusions seen on echocardiography were identified on CT. CONCLUSION: CT signs of severe thoracic trauma are frequently present in patients with severe BCI and should be regarded as indirect evidence of potential BCI. Direct CT findings of myocardial contusion, i.e. myocardial hypoenhancement, are poorly sensitive and should not be used as a screening tool. However, some left ventricular contusions can be seen on CT, and these patients could undergo echocardiography or cardiac MRI to evaluate for wall motion abnormalities.