A 72-year-old man is evaluated in the hospital for acute-onset shortness of breath. He is … — USMLE Step 2 CK

A 72-year-old man is evaluated in the hospital for acute-onset shortness of breath. He is currently on postoperative day 3 following an open partial colectomy for colon cancer. He has a history of hypertension, type 2 diabetes mellitus, and chronic kidney disease. Two hours ago, routine laboratory studies were obtained:

Test	Result
Hemoglobin	$6.8 \text{ g/dL}$
Leukocytes	$8,500/\mu\text{L}$
Platelets	$210,000/\mu\text{L}$
Sodium	$138 \text{ mEq/L}$
Potassium	$4.2 \text{ mEq/L}$
Blood urea nitrogen	$35 \text{ mg/dL}$
Creatinine	$1.8 \text{ mg/dL}$

Due to the symptomatic anemia, a transfusion of packed red blood cells was initiated. Forty-five minutes into the transfusion, the patient develops severe dyspnea and a nonproductive cough.

His temperature is $38.1^\circ\text{C} (100.6^\circ\text{F})$ , blood pressure is $178/96 \text{ mmHg}$ , pulse is $115/\text{min}$ , and respirations are $28/\text{min}$ . Pulse oximetry is $87\%$ on room air.

Physical examination reveals a patient in acute respiratory distress. The jugular veins are distended to the angle of the mandible while sitting at 45 degrees. Cardiac auscultation reveals a regular tachycardia with a prominent $S_{3}$ gallop. Pulmonary auscultation reveals bilateral basilar crackles.

An arterial blood gas on room air shows:
pH: $7.49$
pCO2: $30 \text{ mmHg}$
pO2: $56 \text{ mmHg}$
HCO3: $23 \text{ mEq/L}$

The blood transfusion is immediately stopped, and supplemental oxygen is provided. Which of the following is the most appropriate next step in management?

A
Administer nebulized albuterol and ipratropium
B
Administer broad-spectrum intravenous antibiotics
C
Obtain a urinalysis and urine culture
Administer intravenous furosemideCevap
E
Administer intravenous sodium bicarbonate

Cevap

The most appropriate next step in management is to administer intravenous furosemide to treat Transfusion-Associated Circulatory Overload (TACO).

This patient is experiencing Transfusion-Associated Circulatory Overload (TACO). Risk factors for TACO include advanced age, underlying cardiovascular disease, and chronic kidney disease (which this patient has). The rapid administration of blood products leads to an acute expansion of the intravascular space, causing cardiogenic pulmonary edema. The classic clinical presentation includes acute dyspnea, hypoxemia, hypertension, tachycardia, jugular venous distention, and an

S_{3}

gallop. The arterial blood gas shows an uncompensated respiratory alkalosis due to hypoxia-driven tachypnea, rather than an underlying metabolic derangement. Management of TACO requires immediately halting the transfusion, providing respiratory support (such as supplemental oxygen or positive pressure ventilation), and administering intravenous loop diuretics (e.g., furosemide) to rapidly decrease the volume overload.

Adım Adım Çözüm

Analyze the patient's acute presentation during the packed red blood cell transfusion.

The patient developed severe dyspnea, hypoxemia, hypertension, jugular venous distention, and an

S_{3}

gallop.

Identifying the timing of symptom onset and the hemodynamic profile is crucial for differentiating between types of acute transfusion reactions.

Differentiate between the primary causes of acute respiratory distress following a transfusion.

The combination of acute pulmonary edema, hypertension, and prominent signs of cardiac volume overload (JVD,

S_{3}

gallop) strongly points to Transfusion-Associated Circulatory Overload (TACO).

TACO is a hydrostatic pulmonary edema caused by rapid intravascular volume expansion, whereas TRALI involves immune-mediated increased pulmonary capillary permeability typically presenting with normal or low blood pressure and no signs of fluid overload.

Determine the most appropriate immediate management for TACO based on the diagnosis.

In addition to stopping the transfusion and providing respiratory support, administering intravenous diuretics is required.

Loop diuretics, such as furosemide, promote renal fluid excretion and provide venodilation, rapidly decreasing the excessive intravascular volume and relieving cardiogenic pulmonary edema.

Anahtar Kavram

Transfusion-Associated Circulatory Overload (TACO) presents with signs of cardiogenic volume overload (hypertension, JVD,

S_{3}

gallop, pulmonary crackles) and is managed by halting the transfusion, providing oxygen, and administering intravenous diuretics.

Soru

Cevap

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