Paramedics bring a 68-year-old male patient to the emergency department for the acute onse… — USMLE Step 2 CK

Paramedics bring a 68-year-old male patient to the emergency department for the acute onset of severe breathlessness and right-sided chest discomfort that worsens with deep inspiration. The symptoms began abruptly 2 hours ago. His medical history is significant for metastatic pancreatic adenocarcinoma, for which he is currently receiving palliative chemotherapy. He has no other known medical conditions.

Temperature is $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), blood pressure is $82/50 \text{ mm Hg}$ , pulse is $128/\text{min}$ , and respirations are $30/\text{min}$ . Pulse oximetry shows an oxygen saturation of $85\%$ on room air. The patient appears diaphoretic and in severe respiratory distress. Jugular venous distension is present. Cardiac examination reveals tachycardia, a prominent right ventricular heave, and an accentuated pulmonic component of the second heart sound. The lungs are clear to auscultation bilaterally. The right calf is swollen, warm, and tender to palpation.

Arterial blood gas analysis on room air shows:
$pH$ : $7.54$
$PaCO_2$ : $26 \text{ mm Hg}$
$PaO_2$ : $54 \text{ mm Hg}$
$HCO_3^-$ : $22 \text{ mEq/L}$

An electrocardiogram demonstrates sinus tachycardia with a new right bundle branch block.

Which of the following is the most appropriate next step in the management of this patient?

Perform bedside transthoracic echocardiographyAnswer
B
Transport the patient for computed tomography pulmonary angiography
C
Administer intravenous furosemide and nitroglycerin
D
Initiate empiric therapy with piperacillin-tazobactam
E
Administer intravenous sodium bicarbonate

Answer

Perform bedside transthoracic echocardiography

The correct approach for a hemodynamically unstable patient with a high clinical probability of a massive pulmonary embolism (especially given the history of pancreatic cancer, a highly prothrombotic malignancy) is to perform a bedside transthoracic echocardiogram. This rapidly identifies signs of right ventricular strain (e.g., right ventricular dilation, septal bowing). In the setting of shock, echocardiographic evidence of right ventricular overload provides sufficient justification to initiate life-saving interventions such as thrombolytic therapy or surgical embolectomy, while safely avoiding the extreme risk of transporting a crashing patient to the CT scanner.

Step-by-Step Solution

Identify the primary clinical syndrome and underlying risk factors.

The sudden dyspnea, hypoxia, right ventricular strain, and unilateral calf swelling in a patient with pancreatic cancer indicates a massive pulmonary embolism (Trousseau syndrome).

Recognizing the oncologic emergency and the highly prothrombotic nature of the malignancy is required to prioritize management.

Assess the patient's hemodynamic stability.

The patient is in shock, characterized by a blood pressure of

82/50 \text{ mm Hg}

and tachycardia.

Hemodynamic status strictly dictates whether the patient can safely undergo transport for definitive imaging.

Determine the appropriate diagnostic modality.

Bedside echocardiography is chosen over CT pulmonary angiography.

Unstable patients cannot safely be moved to the CT scanner; bedside echo rapidly identifies right ventricular dysfunction to justify aggressive therapies like thrombolysis.

Key Concept

Management of hemodynamically unstable pulmonary embolism in oncology patients

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