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Difficulty: MediumGeneral Internal Medicine

An 81-year-old woman is urgently evaluated on the medical-surgical unit for acute respiratory distress. She was admitted two days prior for treatment of pyelonephritis and bacteremia, initially receiving 3.5 liters of crystalloid resuscitation along with empiric intravenous piperacillin-tazobactam and vancomycin. Her past medical history includes heart failure with preserved ejection fraction, severe chronic obstructive pulmonary disease (COPD), and hypertension. Today, her blood cultures from admission are finalized, showing growth of Escherichia coli that is susceptible to ceftriaxone but resistant to ampicillin. Currently, she appears anxious and is breathing rapidly. Vital signs are temperature 37.0°C (98.6°F), blood pressure 152/88 mm Hg, heart rate 106/min, and respiratory rate 26/min. Oxygen saturation is 89% on room air. Examination shows jugular venous distention to 12 cm H2O. Auscultation reveals dullness to percussion at the bases with crackles extending halfway up the lung fields. Trace wheezing is also noted. Bilateral lower extremities exhibit 2+ pitting edema.

Laboratory studies drawn an hour ago show:
Leukocyte count: 11,200/mm³
Thyroid-stimulating hormone (TSH): 7.2 mU/L (normal: 0.5–5.0 mU/L)
Free thyroxine (T4): 1.1 ng/dL (normal: 0.9–1.7 ng/dL)

Arterial blood gas (room air):
pH: 7.22
PaCO2: 42 mm Hg
PaO2: 58 mm Hg
HCO3−: 17 mEq/L

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

  1. A
    Continue intravenous piperacillin-tazobactam and vancomycin
  2. Administer intravenous furosemideAnswer
  3. C
    Administer intravenous sodium bicarbonate
  4. D
    Initiate oral levothyroxine
  5. E
    Administer nebulized albuterol and ipratropium

Answer

Administer intravenous furosemide
The correct answer is administering intravenous furosemide. This patient has developed acute decompensated heart failure (ADHF) secondary to aggressive intravenous fluid resuscitation for her initial pyelonephritis. This is evidenced by her elevated jugular venous pressure, bibasilar lung crackles, and peripheral edema. Furthermore, her arterial blood gas reveals a primary metabolic acidosis (likely from her recent sepsis or mild kidney injury) with a superimposed respiratory acidosis. Using Winter's formula, the expected PaCO2PaCO_2 is (1.5×17)+8=33.5±2(1.5 \times 17) + 8 = 33.5 \pm 2 mm Hg. Her actual PaCO2PaCO_2 is 42 mm Hg, indicating she is retaining CO2CO_2 and experiencing impending respiratory failure due to pulmonary congestion. Immediate diuresis with intravenous furosemide is required to reduce preload, alleviate pulmonary edema, and improve gas exchange.

Step-by-Step Solution

1
Synthesize the clinical presentation to identify the primary cause of the patient's acute respiratory distress.
The patient has elevated JVP, bibasilar crackles, and peripheral edema following 3.5 L of IV fluids, pointing to acute decompensated heart failure (ADHF) rather than a COPD exacerbation.
Aggressive fluid resuscitation for sepsis frequently unmasks or exacerbates underlying heart failure with preserved ejection fraction (HFpEF).
2
Analyze the arterial blood gas results using Winter's formula to determine the precise acid-base disturbance.
Expected PaCO2=(1.5×17)+8=33.5±2PaCO_2 = (1.5 \times 17) + 8 = 33.5 \pm 2 mm Hg. The actual PaCO2PaCO_2 is 42 mm Hg, confirming a mixed metabolic acidosis and primary respiratory acidosis.
Identifying the concurrent respiratory acidosis confirms the severity of her pulmonary congestion and impending respiratory failure, ruling out treatments like sodium bicarbonate.
3
Select the most appropriate initial management for ADHF while considering antimicrobial stewardship and thyroid lab interpretation.
Intravenous furosemide is the best next step to relieve pulmonary edema. Broad-spectrum antibiotics should be de-escalated, and the mild TSH elevation should be observed without starting levothyroxine.
Diuresis directly addresses the life-threatening respiratory failure, whereas the other options represent medical errors or fail to treat the primary acute issue.

Key Concept

Recognition and management of acute decompensated heart failure (ADHF) precipitated by volume resuscitation, interpretation of mixed acid-base disorders, and appropriate medication stewardship.

Alternative Method

Bedside point-of-care ultrasound (POCUS) of the lungs can be rapidly utilized to differentiate Acute Decompensated Heart Failure (indicated by the presence of diffuse bilateral B-lines) from a COPD exacerbation (predominantly A-lines without B-lines) before waiting for laboratory or radiographic results.
Estimated Time:1m 30s
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Topics

General Internal Medicine

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