A 35-year-old previously healthy man is brought to the emergency department after being involved in a motor vehicle collision. He was an unrestrained driver and hit his chest against the steering wheel during the collision. When the paramedics reached him, he reported chest discomfort but was hemodynamically stable. Shortly after arrival at the emergency department, the patient experiences worsening respiratory distress and becomes hypotensive. On physical examination, the patient appears anxious and is tachycardic and tachypneic. The trachea is midline; the jugular veins are distended. The anterior chest wall is bruised and tender to palpation. Vesicular breath sounds are present bilaterally. The abdomen is soft and nontender. Which of the following is the most likely cause of this patient's clinical deterioration?

Question

A 35-year-old previously healthy man is brought to the emergency department after being involved in a motor vehicle collision.  He was an unrestrained driver and hit his chest against the steering wheel during the collision.  When the paramedics reached him, he reported chest discomfort but was hemodynamically stable.  Shortly after arrival at the emergency department, the patient experiences worsening respiratory distress and becomes hypotensive.  On physical examination, the patient appears anxious and is tachycardic and tachypneic.  The trachea is midline; the jugular veins are distended.  The anterior chest wall is bruised and tender to palpation.  Vesicular breath sounds are present bilaterally.  The abdomen is soft and nontender.  Which of the following is the most likely cause of this patient's clinical deterioration?

Quizplus · Accepted Answer

11ec160b_38c5_2bf4_9249_bbe5c34d3900_MD0001_00 This patient experienced significant blunt chest trauma when his chest struck the steering wheel, evidenced by anterior chest wall bruising and tenderness on examination. Such trauma can lead to several life-threatening cardiopulmonary injuries; this patient with progressive hypotension, tachycardia, and jugular venous distension most likely has acute cardiac tamponade. Blunt cardiac injury can cause rapid accumulation of blood within the pericardium. Because the pericardium is relatively noncompliant and does not have time to adapt, even a small amount of pericardial fluid (eg, 100-200 mL) can dramatically increase intrapericardial pressure and lead to tamponade. The increased pericardial pressure compresses the relatively low-pressure, right-sided heart chambers and restricts diastolic filling of the right side of the heart. This elevates right atrial pressure, which is transmitted backward to the vena cava, the central venous system, and the jugular veins (causing distension). With decreased right-sided filling, less blood is pumped through the pulmonary circulation to the left atrium and left ventricle, resulting in decreased cardiac output. This results in systemic hypotension, despite compensatory tachycardia. Impaired peripheral perfusion leads to unmet oxygen demand in the tissues with resulting dyspnea, increased respiratory drive, and tachypnea. (Choice A) Blunt deceleration during chest trauma can cause tearing of the aorta (ie, aortic rupture). However, aortic rupture usually causes massive internal hemorrhage with rapidly developing hypovolemic shock (eg, flat jugular veins). Most affected patients do not survive transport to the hospital. (Choice C) Diaphragmatic rupture can occur with blunt trauma, typically from a sudden increase in intraabdominal pressure. It may result in intrathoracic herniation of abdominal organs and respiratory symptoms (eg, dyspnea, tachypnea), but it often causes abdominal tenderness and does not typically cause significant bleeding or hypotension. (Choice D) Blunt chest trauma could cause a massive hemothorax with hypotension and tachycardia (ie, hypovolemic shock) as well as tachypnea due to the mass effect on the lung. However, flat jugular veins and absent basilar breath sounds are expected. (Choice E) Tension pneumothorax can result from blunt chest trauma that injures the visceral pleura or tracheobronchial tree. It can cause tachypnea and obstructive shock (eg, hypotension, tachycardia, jugular venous distension); however, unilaterally absent breath sounds are expected, and tracheal deviation is often present. Educational objective: Blunt chest trauma can lead to several life-threatening cardiopulmonary injuries. Progressive hypotension with tachycardia, jugular venous distension, and bilateral vesicular breath sounds suggests acute cardiac tamponade.

A 35-Year-Old Previously Healthy Man Is Brought to the Emergency