Chest Injuries—Cardiac Injury

Blunt cardiac injury is a rare and poorly understood phenomenon that must be excluded in any patient who has sustained a frontal impact to the chest. Bruising or edema of the myocardium is functionally indistinguishable from myocardial ischemia and may be causally related because the pathophysiology of cardiac contusion may involve forcible dislodgment of unstable atherosclerotic plaques. If the patient is hemodynamically stable and the electrocardiogram does not demonstrate conduction disturbances or tachyarrhythmias, blunt cardiac injury can be safely excluded.^[209] If either a new tachyarrhythmia or conduction disturbance subsequently develops or the patient has unexplained hypotension, other causes (hypovolemia, renal failure) should be ruled out first. If the workup is negative, transthoracic echocardiography (TTE) should be performed. Right ventricular dysfunction resulting in hypotension may be overlooked while more common etiologies of hypotension in a trauma patient are being evaluated. TEE is superior to TTE in obese patients or those with injuries to the chest wall that make it difficult to obtain adequate acoustic windows, but it will generally require intubation and deep sedation to accomplish. Once diagnosed, blunt cardiac injury should be managed as ischemic cardiac injury, with completion of resuscitation and then careful control of fluid volume, administration of coronary vasodilators, and monitoring and symptomatic treatment of rhythm disturbances. Cardiology consultation is appropriate if the patient might benefit from coronary angiography followed by angioplasty or stenting of stenotic vessels.

Penetrating cardiac trauma and blunt trauma causing rupture of one or more chambers (usually the atria) will infrequently be seen in trauma centers because of high prehospital mortality. Patients who do not die immediately of free exsanguination into the thoracic cavity will have pericardial tamponade and can be extremely unstable in the first minutes after admission. This condition is diagnosed by clinical suspicion, by FAST, and by direct inspection of a patient who has lost vital signs and has thus undergone ED thoracotomy. Relief of the tamponade and clamp or suture control of the cardiac injury may allow restoration of spontaneous circulation if accomplished swiftly enough, with subsequent transition to the OR for definitive hemostasis and chest closure.