A 45-year-old man is brought to the emergency department by emergency medical services aft… — USMLE Step 2 CK

A $45$ -year-old man is brought to the emergency department by emergency medical services after a high-speed motor vehicle collision. He was an unrestrained driver and was ejected from the vehicle. On arrival, he is agitated, pale, and diaphoretic. His blood pressure is $76/40 \text{ mm Hg}$ , heart rate is $138\text{/min}$ , and respiratory rate is $24\text{/min}$ . The airway is patent, and the trachea is midline. Breath sounds are present and equal bilaterally. Heart sounds are normal. The abdomen is distended and diffusely tender with mild rigidity. The pelvis is mechanically stable to anteroposterior and lateral compression. Intravenous access is established, and the mass transfusion protocol is initiated. Following the administration of $1 \text{ L}$ of warmed crystalloid and $1 \text{ unit}$ of uncrossmatched packed red blood cells, his blood pressure is $82/45 \text{ mm Hg}$ . A focused assessment with sonography for trauma (FAST) reveals a large amount of anechoic fluid in the hepatorenal and splenorenal recesses; there is no fluid in the pericardial sac. A portable anteroposterior chest radiograph demonstrates clear lung fields but a noticeably widened mediastinum with blurring of the aortic knob. Which of the following is the most appropriate next step in the management of this patient?

Exploratory laparotomyAnswer
B
Computed tomography angiography of the chest and abdomen
C
Transesophageal echocardiography
D
Left anterolateral thoracotomy
E
Diagnostic peritoneal lavage

Answer

Exploratory laparotomy

The correct answer is exploratory laparotomy. This patient presents with profound hemorrhagic shock following blunt trauma. The positive FAST scan confirms that the source of his hypovolemia is massive intra-abdominal bleeding. The widened mediastinum on his chest radiograph strongly suggests a blunt thoracic aortic injury (BTAI). This creates a clinical dilemma regarding competing priorities. However, Advanced Trauma Life Support (ATLS) principles dictate that the most active, life-threatening source of hemorrhage must be addressed first. Patients with BTAI who survive long enough to reach the emergency department almost always have a contained hematoma rather than a free rupture. The active bleeding causing this patient's shock is occurring in the abdomen. Therefore, immediate exploratory laparotomy is the mandatory next step to stop the exsanguination. Once the intra-abdominal bleeding is controlled and the patient is stabilized, the suspected aortic injury can be safely evaluated, either concurrently in the operating room via transesophageal echocardiography or postoperatively via computed tomography angiography.

Step-by-Step Solution

Identify the patient's hemodynamic status.

The patient is in severe, refractory hemorrhagic shock (blood pressure

76/40 \text{ mm Hg}

, minimal response to initial resuscitation).

Hemodynamic instability dictates that diagnostic testing must be minimized and therapeutic intervention expedited.

Analyze the results of the primary and secondary survey adjuncts.

FAST is positive for massive intra-abdominal fluid. The chest radiograph shows a widened mediastinum, raising high suspicion for a blunt thoracic aortic injury (BTAI).

Identifying all potential sources of hemorrhage is critical for surgical planning.

Prioritize interventions based on ATLS guidelines for competing life-threatening injuries.

The active, exsanguinating intra-abdominal hemorrhage (proven by FAST) is the immediate cause of shock. A contained aortic hematoma (BTAI) does not typically cause massive active shock unless it completely ruptures, which is rapidly fatal.

According to trauma protocols, controlling active exsanguination in the abdomen takes precedence over definitively diagnosing or treating a suspected, contained aortic injury.

Select the definitive management step.

Exploratory laparotomy must be performed immediately.

The patient requires immediate surgical control of the abdominal bleeding. The aorta can be evaluated intraoperatively (with transesophageal echocardiography) or postoperatively once the patient is stabilized.

Key Concept

In a hemodynamically unstable blunt trauma patient with multiple competing injuries, active exsanguination from an intra-abdominal source (positive FAST) takes immediate operative priority over the diagnostic workup of a suspected blunt thoracic aortic injury.

Estimated Time:1m 30s

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