A 78-year-old woman is evaluated for sudden-onset severe shortness of breath. She was admi… — USMLE Step 2 CK

A 78-year-old woman is evaluated for sudden-onset severe shortness of breath. She was admitted to the hospital two days ago for symptomatic anemia secondary to a bleeding duodenal ulcer, which was successfully treated with endoscopic clipping. Two hours ago, she completed a transfusion of two units of packed red blood cells. She has a medical history of hypertension and chronic kidney disease. Her temperature is $37.1^\circ \text{C}$ ( $98.8^\circ \text{F}$ ), blood pressure is $182/98\text{ mm Hg}$ , pulse is $112/\text{min}$ , and respiratory rate is $28/\text{min}$ . Pulse oximetry shows an oxygen saturation of $86\%$ on room air. Physical examination reveals elevated jugular venous pressure and a prominent $S_3$ gallop. Pulmonary auscultation reveals bilateral crackles extending to the mid-lung fields.

Relevant laboratory results are shown below:

Test	Result	Reference Range
Hemoglobin	$9.4\text{ g/dL}$	$12.0-16.0\text{ g/dL}$
Calcium, total	$9.0\text{ mg/dL}$	$8.4-10.2\text{ mg/dL}$
B-type natriuretic peptide (BNP)	$1250\text{ pg/mL}$	$<100\text{ pg/mL}$

Arterial blood gas analysis on room air shows:

Test	Result	Reference Range
pH	$7.48$	$7.35-7.45$
$\text{PaO}_2$	$54\text{ mm Hg}$	$75-105\text{ mm Hg}$
$\text{PaCO}_2$	$30\text{ mm Hg}$	$35-45\text{ mm Hg}$
$\text{HCO}_3^-$	$22\text{ mEq/L}$	$22-28\text{ mEq/L}$

A portable chest radiograph demonstrates bilateral perihilar alveolar opacities and an enlarged cardiac silhouette.

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

A
Administer intravenous sodium bicarbonate
B
Administer intravenous piperacillin-tazobactam
Administer intravenous furosemideAnswer
D
Administer inhaled albuterol and ipratropium
E
Administer intravenous calcium gluconate

Answer

Administer intravenous furosemide

The correct answer is to administer intravenous furosemide. This patient is experiencing transfusion-associated circulatory overload (TACO), a serious complication characterized by cardiogenic pulmonary edema resulting from the osmotic and volume loads of transfused blood products. It most commonly occurs in older adults or those with underlying cardiovascular or renal disease. The clinical presentation of TACO includes respiratory distress, hypoxia, hypertension, tachycardia, and signs of left heart failure such as an S3 gallop, elevated jugular venous pressure, and pulmonary crackles. The elevated B-type natriuretic peptide (BNP) and radiographic evidence of cardiomegaly confirm the cardiogenic nature of the edema. Management involves immediately stopping the transfusion (if still running), providing supplemental oxygen, and administering intravenous loop diuretics (e.g., furosemide) to reduce intravascular volume.

Step-by-Step Solution

Analyze the patient's vital signs and physical examination findings following a blood transfusion.

The patient developed acute hypoxia, hypertension, tachycardia, jugular venous distension, an S3 gallop, and bilateral pulmonary crackles.

These findings are classic for acute left-sided heart failure and volume overload, pointing toward transfusion-associated circulatory overload (TACO).

Interpret the laboratory and imaging data to differentiate between causes of post-transfusion respiratory distress.

The chest radiograph shows cardiomegaly and alveolar opacities. The BNP is significantly elevated. The ABG shows hypoxia with a reactive respiratory alkalosis.

Elevated BNP and cardiomegaly strongly differentiate TACO (cardiogenic edema) from transfusion-related acute lung injury (TRALI), which causes noncardiogenic pulmonary edema typically associated with hypotension and a normal BNP.

Determine the optimal medical management for the diagnosed condition.

The most appropriate next step is to administer an intravenous loop diuretic such as furosemide, alongside supplemental oxygen.

Diuresis rapidly reduces intravascular volume and hydrostatic pressure, thereby resolving the cardiogenic pulmonary edema.

Key Concept

Diagnosis and management of Transfusion-Associated Circulatory Overload (TACO)

Estimated Time:1m 30s

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