Background: Cardiac trauma is associated with a high mortality rate, but a subset of the patients presents with normal vital signs in the emergency department. Identification of cardiac injuries in these patients can be a challenge. Many investigative modalities have been used to identify penetrating cardiac injury patients. Most of these tests are expensive, specialised and not easily accessible. However, the role of Troponins in penetrating cardiac injury has not been defined. We hypothesised that cardiac troponins have a negative predictive value in penetrating cardiac injuries in those who have normal haemodynamic status and do not have clinical or radiological features on cardiac injury.
Materials and Methods:We retrospectively reviewed all patients who presented to the Charlotte Maxeke Academic Hospital trauma unit over 22 months (01 January 2018 to 31 October 2020). Patients were identified using the hospital database. All patients with penetrating trauma to the cardiac zone above 18 years, who were haemodynamically normal and did not have obvious clinical or radiological features suggestive of cardiac injury, were included. The patient's demographics, mechanism of injury, injury severity score, vital signs, investigation findings, troponin levels, final diagnosis, type of operation, length of hospital stay, morbidities and mortalities were recorded. Those with no confirmed injuries were discharged home after minimal 24hr observation and repeat radiological examinations.Results: There was a total of 173 patients identified; 6 were females. The median age was 30 years. Most patients (160/173) had stab wounds. The median Injury Severity Score (ISS) was 12.8. Most patients sustained stab wounds on the left side of the chest (n=90), 52%. Initial ultrasound was positive for pericardial fluid in 10% of patients (n=18). The sensitivity of cardiac troponins was 85.7%, and the specificity was 69.2%. The negative and positive predictor values were 98% and 19.7%, respectively. The mean initial Troponins level was 50 ng/L. The mean repeat troponins were 450 ng/L in those patients with cardiac injuries. The Troponins were significantly different in those with cardiac injuries and those without cardiac injuries. Fourteen patients had a cardiac injury, the right ventricle (3.5%) was the most injured chamber, followed by the left ventricle (2.3%) and Right atrium (0.6%). Two patients sustained myocardial injuries without chamber penetration. The overall mortality rate was 0,6%(n=1). Fifty percent of the patients (n=87) were discharged home from the emergency department, 21.8% were admitted to the ward (n=38), and 15.5% (n=27) were admitted to the Trauma ICU. The average hospital stay was one day for patients with a stab to the precordium.
Conclusion:Troponins can be used to evaluate cardiac injuries in haemodynamically normal patients with penetrating chest trauma. Serum Troponins have an excellent negative predictor value (98%). More prospective data is needed to confirm our findings and then extend to clinical practice,...