A 22-year-old man is brought to the emergency department by ambulance 15 minutes after sus… — USMLE Step 2 CK

A $22$ -year-old man is brought to the emergency department by ambulance $15$ minutes after sustaining a stab wound to the left side of his chest during an altercation. On arrival, the patient is agitated and diaphoretic. His temperature is $36.8^\circ\text{C}$ ( $98.2^\circ\text{F}$ ), blood pressure is $82/40 \text{ mmHg}$ , pulse is $132/\text{min}$ , and respiratory rate is $26/\text{min}$ . Pulse oximetry shows $94\%$ on room air. Primary survey reveals a $3 \text{ cm}$ linear laceration in the left $6^{\text{th}}$ intercostal space at the midaxillary line. The trachea is midline. Breath sounds are markedly diminished on the left side of the chest. The abdomen is slightly distended and diffusely tender to palpation. A left-sided tube thoracostomy is placed, draining $400 \text{ mL}$ of gross blood and a small amount of bubbling air. Five minutes after chest tube placement, breath sounds are equal bilaterally, and oxygen saturation improves to $99\%$ . However, his blood pressure remains $80/42 \text{ mmHg}$ and pulse is $135/\text{min}$ despite rapid intravenous infusion of $1 \text{ L}$ of warmed crystalloid solution. A bedside focused assessment with sonography for trauma (FAST) demonstrates a large anechoic fluid collection in the splenorenal recess, with no pericardial effusion identified. Which of the following is the most appropriate next step in management?

A
Computed tomography of the abdomen and pelvis with intravenous contrast
B
Urgent exploratory thoracotomy
Immediate exploratory laparotomyAnswer
D
Diagnostic peritoneal lavage
E
Local wound exploration of the chest wall

Answer

Immediate exploratory laparotomy

The correct answer is immediate exploratory laparotomy. This patient presents with a penetrating injury to the thoracoabdominal region. The diaphragm can rise as high as the

4^{\text{th}}

intercostal space during expiration; thus, any penetrating injury below the nipple line carries a high risk of involving the abdominal cavity. Despite adequately addressing his left-sided hemopneumothorax with a tube thoracostomy (indicated by improved oxygenation and equalized breath sounds), he remains in refractory hemorrhagic shock (persistent hypotension and tachycardia). The bedside FAST exam definitively localizes the source of the ongoing hemorrhage to the abdomen. The combination of penetrating trauma, hemodynamic instability, and a positive FAST exam is an absolute indication for immediate exploratory laparotomy to surgically control the bleeding.

Step-by-Step Solution

Identify the anatomic risk zone of the injury.

The

6^{\text{th}}

intercostal space is located below the nipple line (roughly the

4^{\text{th}}

intercostal space anteriorly). This is the thoracoabdominal region, meaning penetrating trauma here can violate the diaphragm and cause intra-abdominal injury.

To recognize the potential for dual-cavity involvement in lower chest wounds.

Assess the patient's hemodynamic status and response to initial interventions.

The patient presents in class III/IV hemorrhagic shock. Tube thoracostomy resolves the respiratory compromise, but the patient remains profoundly hypotensive and tachycardic despite initial fluid resuscitation.

To determine if the thoracic injury (hemopneumothorax) is the primary driver of the instability or if there is another source of hemorrhage.

Interpret the FAST exam.

The FAST reveals fluid in the splenorenal recess, confirming intra-abdominal bleeding, while ruling out pericardial tamponade.

To definitively locate the source of ongoing, life-threatening hemorrhage.

Select the definitive management step.

Immediate exploratory laparotomy is chosen.

A hemodynamically unstable trauma patient with a confirmed intra-abdominal source of hemorrhage requires emergent surgical exploration.

Key Concept

Hemodynamically unstable patients with penetrating thoracoabdominal trauma and a positive FAST exam require immediate exploratory laparotomy, even if concurrent thoracic injuries have been identified and treated.

Estimated Time:2m 0s

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