Emergency medical services bring a 61-year-old woman to the resuscitation bay immediately … — USMLE Step 2 CK

Emergency medical services bring a $61$ -year-old woman to the resuscitation bay immediately after she collapsed at home. She regained consciousness after a few minutes but currently complains of severe, abrupt-onset dyspnea and right-sided chest pain. Her surgical history is notable for an uncomplicated right total hip arthroplasty performed three weeks ago.

Vital signs are temperature $37.9^{\circ}$ C ( $100.2^{\circ}$ F), blood pressure $72/46$ mmHg, heart rate $134$ /min, and respiratory rate $28$ /min. Oxygen saturation is $85\%$ on ambient air. Physical examination shows elevated jugular venous pressure and a loud pulmonary component of the second heart sound ( $P_2$ ). The lungs are clear to auscultation bilaterally. The right calf exhibits mild asymmetric edema.

A rapid bedside echocardiogram reveals severe right ventricular dilation with marked hypokinesis of the free wall and normal apical contractility.

Arterial blood gas analysis on ambient air shows:

pH: $7.22$
$PaCO_2$ : $28$ mmHg
$PaO_2$ : $54$ mmHg
$HCO_3^-$ : $11$ mEq/L

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

Administer intravenous alteplaseAnswer
B
Transport the patient for computed tomography pulmonary angiography
C
Administer intravenous furosemide
D
Administer intravenous sodium bicarbonate
E
Obtain blood cultures and start broad-spectrum antibiotics

Answer

Administer intravenous alteplase

The correct next step is to administer intravenous alteplase. This patient presents with a massive pulmonary embolism (PE), defined by the presence of acute PE accompanied by hemodynamic instability (systolic blood pressure

< 90

mmHg). The classic triad of elevated jugular venous pressure, clear lungs, and hypotension points to obstructive shock. The bedside echocardiogram showing right ventricular free wall hypokinesis with apical sparing (McConnell's sign) provides sufficient diagnostic evidence in this unstable patient. For massive PE, systemic thrombolysis is the treatment of choice to quickly reduce the clot burden, lower pulmonary artery pressure, and restore right ventricular output. The mortality benefit of thrombolytics outweighs the risk of hemorrhage in this life-threatening scenario.

Step-by-Step Solution

Analyze the patient's hemodynamic status and clinical presentation.

The patient is in shock (blood pressure

72/46

mmHg) with severe hypoxia, recent surgery, and signs of right ventricular overload (elevated JVP, loud

P_2

Identifying hemodynamic instability dictates whether the patient can safely undergo definitive imaging or requires empiric bedside treatment.

Interpret the bedside echocardiogram and arterial blood gas findings.

Echocardiography shows classic McConnell's sign (RV free wall hypokinesis with apical sparing), strongly suggesting acute pulmonary embolism. ABG reveals severe metabolic acidosis with inadequate respiratory compensation (impending respiratory failure).

In unstable patients, bedside ultrasound provides critical diagnostic clues without the risk of transport.

Determine the optimal intervention for massive pulmonary embolism.

Systemic thrombolytic therapy (e.g., intravenous alteplase) is indicated to rapidly dissolve the clot and restore right ventricular output.

Standard anticoagulation (e.g., heparin) prevents further clot propagation but does not rapidly break down the existing obstruction causing the shock.

Key Concept

Management of massive pulmonary embolism involves rapid recognition via bedside echocardiography and prompt administration of systemic thrombolytics in hemodynamically unstable patients.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic