What is the management of blunt cardiac trauma?

Management of Blunt Cardiac Trauma

Immediate Hemodynamic Assessment

The first and most critical step is determining hemodynamic stability, as this dictates the entire diagnostic and therapeutic pathway. 1, 2

• Hemodynamically unstable patients (persistent systolic blood pressure <90 mm Hg or mean arterial pressure <65 mm Hg despite fluid resuscitation) require immediate FAST examination at bedside to exclude pericardial tamponade and tension pneumothorax/hemothorax 1, 2
• If FAST reveals pericardial tamponade or the patient is in extremis, proceed directly to resuscitative thoracotomy with pericardotomy—closed chest CPR is ineffective in these circumstances 3
• For unstable patients without immediate surgical indication, perform limited fluid resuscitation with crystalloid targeting systolic blood pressure 80-100 mm Hg until major bleeding is controlled 4
• Do not perform preoperative pericardiocentesis in blunt cardiac trauma—this is contraindicated and delays definitive surgical management 5

Diagnostic Algorithm for Stable Patients

In hemodynamically stable patients, obtain ECG and cardiac troponin levels immediately. 2

• Patients with normal ECG AND normal cardiac troponin can be safely discharged—they are low probability for significant blunt cardiac injury 2
• If either ECG or troponin is abnormal, proceed with further cardiac assessment 2
• CT chest with IV contrast is the imaging modality of choice for stable patients, providing comprehensive evaluation of cardiac chambers, pericardium, coronary arteries, and concomitant thoracic injuries 1, 2
• ECG-gated cardiac CT can detect cardiac chamber rupture, pericardial rupture, ventricular pseudoaneurysm, coronary artery dissection, and myocardial infarction that may be missed on echocardiography 1

Role of Echocardiography

Transthoracic echocardiography (TTE) should be performed in stable patients with signs of heart failure, abnormal heart sounds, or need to assess myocardial dysfunction. 1, 2, 4

• TTE is useful for diagnosing the cause of dysfunction, estimating volume resuscitation needs, identifying right ventricular dysfunction requiring arrhythmia monitoring, and detecting wall motion abnormalities 1, 2
• Transesophageal echocardiography (TOE) is superior to TTE for investigating persistent hemodynamic instability of unclear etiology, providing clearer visualization of valvular tears, septal ruptures, and wall motion abnormalities 1, 4
• TOE is contraindicated in patients with cervical spine fractures (present in 5-25% of trauma patients) 1
• Do not perform echocardiography for isolated sternal fractures if ECG and troponin are normal 4

Spectrum of Injuries and Specific Findings

Blunt cardiac injury ranges from clinically silent transient arrhythmias to deadly cardiac wall rupture. 1, 2

• The right ventricle is most commonly affected due to its anterior location, followed by left ventricle and right atrium 1
• Key CT findings requiring immediate intervention include:
  • High-attenuation pericardial effusion with distention of IVC, renal veins, SVC, and azygos veins (suggests tamponade) 1
  • Empty pericardial sac with "collar sign" (constriction of cardiac contour by pericardial tear) indicating heart herniation/strangulation—a high mortality complication 1
  • Contrast extravasation from cardiac chambers indicating active bleeding 1
  • Enhancement defects in myocardium suggesting traumatic myocardial infarction from coronary dissection 1

Surgical Intervention Timing

For patients requiring operative treatment, early recognition and expeditious thoracotomy within 1 hour is essential for survival. 5

• Patients with large cardiac ruptures typically die at the scene, but those with tears in low-pressure cavities who reach the hospital can achieve 70-80% survival with prompt surgery 3
• Overall mortality for operative blunt cardiac injury is approximately 33%, with death directly attributable to cardiac injury in the majority 5
• The main mechanism is motor vehicle collisions (49%), particularly steering wheel injuries 5

Critical Pitfalls to Avoid

• Never assume hypotension is solely from hemorrhage in isolated chest trauma—always exclude tamponade and tension pneumothorax first 1, 4
• Do not underestimate tissue damage in blast injuries—these cause more extensive injury than apparent on initial assessment 1, 4
• Do not clamp a bubbling chest tube as this may convert simple pneumothorax to tension pneumothorax 6
• Normal clinical signs and normal ECG do not exclude cardiac tamponade 3