A 33-year-old morbidly obese man presents to the ED after being an unrestrained passenger in a high-speed motor vehicle accident. On evaluation, it is noted that he has distended neck veins, difficulty breathing, and hyperresonance to percussion on the right. Breath sounds are difficult to auscultate.
What is the MOST likely diagnosis and appropriate treatment for this patient?
A. Cardiac tamponade, pericardiocentesisCorrect Answer: C
The primary survey is designed to rapidly assess and treat any lifethreatening injuries. Major causes of death in trauma patients are airway obstruction, respiratory failure, shock from hemorrhage, and brain injuries. Specific injuries which are immediately life-threatening include:
The patient’s clinical signs and symptoms are most consistent with TPX which should be treated with immediate decompression. TPX results from the trapping of air within the pleural space which does not have a way to escape. Progressive build-up of pressure in the pleural space pushes the mediastinum to the opposite hemithorax and obstructs venous return to the heart. This leads to circulatory instability and may result in traumatic arrest.
Classic signs of a TPX include deviation of the trachea away from the side with the tension, absent breath sounds, hyperresonance to percussion, deviated trachea, and distended neck veins. However these classic signs may be absent and more commonly the patient is tachycardic and tachypneic, and may be hypoxic.
Treatment of TPX is decompression. This will allow the mediastinum and associated organs to return to their normal positions and relieve the pressure. Whether the initial decompression is with a chest tube versus a needle is dependent on the clinician’s skill set, available equipment, and the urgency of the need for decompression. Of note, a standard 14 gauge angiocatheter cannot penetrate the chest wall and reach the pleural space in up to one-third of trauma patients. A 10-gauge, 7.5 cm (3 inch) armored angiocatheter is able to penetrate the pleural space in most instances. If needle decompression is performed, it should be followed immediately by tube thoracostomy.
Cardiac tamponade is most commonly caused by penetrating injuries, such as gunshot or stab wounds, which cause blood to pool in the fixed, fibrous pericardial sac that leads to decreased venous return to the heart and resultant decreased cardiac output. Cardiac tamponade is a clinical diagnosis based on physical findings of muffled heart sounds, dilated neck veins, and hypotension which is known as “Beck triad.” Cardiac tamponade can lead to Kussmaul sign (increased venous pressure with inspiration) and can progress to pulseless electrical activity. Treatment varies on the patient’s clinical situation, ranging from pericardiocentesis to resuscitative thoracotomy. Differentiating between TPX and cardiac tamponade may be challenging as both can result in hemodynamic compromise or cardiac arrest. Asymmetric absence of breath sounds, hyperresonance to percussion, and tracheal deviation are signs of TPX that are not seen in cardiac tamponade. An ultrasound exam utilizing FAST protocol, if available, can be valuable in diagnosing and differentiating between these conditions.
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