A 74-year-old man is evaluated on the inpatient medical ward due to the sudden onset of se… — USMLE Step 2 CK

A 74-year-old man is evaluated on the inpatient medical ward due to the sudden onset of severe shortness of breath and a dry cough. He was admitted $2\text{ days}$ ago for symptomatic anemia secondary to newly diagnosed myelodysplastic syndrome. His past medical history is significant for ischemic cardiomyopathy with a left ventricular ejection fraction of $35\%$ , type 2 diabetes mellitus, and a 40-pack-year smoking history. The patient is currently $45\text{ minutes}$ into a transfusion of his second unit of packed red blood cells (PRBCs). His temperature is $37.0^\circ\text{C}$ ( $98.6^\circ\text{F}$ ), heart rate is $118/\text{min}$ , respiratory rate is $28/\text{min}$ , and blood pressure is $172/96\text{ mmHg}$ . Pulse oximetry shows an oxygen saturation of $85\%$ on room air. The patient is in acute respiratory distress and is using accessory muscles of respiration. Jugular venous pulsation is visible at $13\text{ cm H}_2\text{O}$ . Lung auscultation reveals bilateral crackles halfway up the posterior lung fields and scattered expiratory wheezes. Cardiac examination reveals a regular tachycardia with a prominent $S_3$ gallop. There is no skin rash or urticaria. Arterial blood gas on room air shows a pH of $7.28$ , $\text{PaCO}_2$ of $58\text{ mmHg}$ , and $\text{HCO}_3^-$ of $26\text{ mEq/L}$ . Which of the following is the most appropriate next step in the management of this patient?

Discontinue the transfusion and administer intravenous furosemideCevap
B
Discontinue the transfusion and administer nebulized albuterol with intravenous methylprednisolone
C
Discontinue the transfusion, obtain blood cultures, and administer intravenous piperacillin-tazobactam
D
Discontinue the transfusion and administer a continuous intravenous sodium bicarbonate infusion
E
Discontinue the transfusion and contact the blood donor directly to investigate for transmissible pathogens

Cevap

Discontinue the transfusion and administer intravenous furosemide

This patient is experiencing Transfusion-Associated Circulatory Overload (TACO), a highly morbid complication in elderly patients or those with underlying cardiopulmonary dysfunction (e.g., ischemic cardiomyopathy). The administration of blood products leads to an acute increase in intravascular volume that the impaired left ventricle cannot accommodate, manifesting rapidly as cardiogenic pulmonary edema. Key diagnostic features include respiratory distress during or within 6 hours of transfusion, significant hypertension, tachycardia, widened pulse pressure, and signs of left heart failure such as elevated jugular venous pressure, bilateral crackles, and an

S_3

gallop. The most appropriate immediate management is to halt the offending transfusion, provide supplemental oxygen or ventilatory support, and administer loop diuretics (e.g., intravenous furosemide) to reduce intravascular volume.

Adım Adım Çözüm

Analyze the patient's acute presentation during a blood transfusion.

The patient developed acute respiratory distress, hypoxemia, significant hypertension, tachycardia, elevated JVP, bilateral crackles, and an S3 gallop.

Identifying the timeline and the specific constellation of hemodynamic findings is crucial for differentiating transfusion reactions.

Review the patient's past medical history and risk factors.

The patient is elderly with ischemic cardiomyopathy and a reduced ejection fraction (35%).

Patients with underlying cardiopulmonary dysfunction are at the highest risk for Transfusion-Associated Circulatory Overload (TACO) due to their inability to handle rapid increases in intravascular volume.

Differentiate TACO from Transfusion-Related Acute Lung Injury (TRALI).

The presence of significant hypertension, elevated JVP, and an S3 gallop confirms cardiogenic pulmonary edema (TACO), whereas TRALI typically presents with hypotension and normal cardiac filling pressures.

While both present with respiratory distress during or shortly after transfusion, their pathophysiologic mechanisms and treatments are vastly different.

Determine the appropriate management.

The transfusion must be stopped immediately, and the volume overload must be reversed with intravenous loop diuretics (e.g., furosemide) and supplemental oxygen.

Loop diuretics rapidly reduce intravascular volume, alleviating the cardiogenic pulmonary edema and correcting the resulting hypoxemia and respiratory acidosis.

Anahtar Kavram

Transfusion-Associated Circulatory Overload (TACO)

Soru

Cevap

Adım Adım Çözüm

Anahtar Kavram

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