Clinically significant blunt cardiac trauma: role of serum troponin levels combined with electrocardiographic findings

Aim—The authors attempted to answer three questions. Firstly, which trauma patients are at risk of significant blunt cardiac trauma (BCT); secondly, what is the value of the electrocardiogram (ECG) and cardiac troponin I (cTnI) measurement in determining significant BCT; and finally, how long do patients at risk of significant BCT have to be monitored for?

Methods—Prospective study of all blunt trauma victims with any risk of BCT admitted to a level 1 trauma centre in the USA over a 10 month period. Patients were said to be at risk of BCT if they had: rib fractures; sternal fracture; pneumothorax; haemothorax; thoracic seat belt sign, or pulmonary contusion. They were managed in a standardised manner by the in house surgeons, and all were investigated with ECG (0 and 8 hours), cTnI (0 and 4 hours) and chest radiography. Patients were analysed according to the presence or absence of significant BCT. Significant BCT was defined as the presence after trauma of: cardiogenic shock requiring inotropes; arrhythmias requiring treatment; structural cardiac abnormalities, or unexplained hypotension requiring vasopressors.

Results—115 patients were enrolled, of whom 19 (16.5%) had significant BCT. Eighteen of these became evident within the first 24 hours (one had a haemopericardium detected at day six). ECG abnormalities were detected in 58 (50%), and cTnI was increased in 27 (24%). All ECG abnormalities and 22 of the 27 patients with increased cTnI were apparent on arrival, the other five patients having increased cTnI within four hours (all five had an abnormal initial ECG). The combination of both tests gave a positive predictive value of 62% (both tests abnormal), and a negative predictive value of 100% (both tests normal). Six risk factors were identified as being independently associated with significant BCT: abnormal ECG (adjusted relative risk (ARR) of 14.0); abnormal cTnI …