What is flushed pulmonary edema?

Flushed Pulmonary Edema

Flushed pulmonary edema is a clinical presentation of acute pulmonary edema characterized by warm extremities, peripheral vasodilation, and normal or elevated blood pressure, typically seen in hypertensive heart failure with preserved left ventricular function. 1

Clinical Presentation and Pathophysiology

Flushed pulmonary edema represents one specific phenotype of acute pulmonary edema with distinct hemodynamic characteristics:

• Appearance: Patients present with warm, well-perfused extremities (hence "flushed")
• Blood pressure: Normal to elevated (often hypertensive)
• Cardiac function: Relatively preserved left ventricular systolic function
• Pathophysiology: Results from a combination of:
  • Increased systemic vascular resistance
  • Fluid redistribution rather than fluid accumulation
  • Acute increase in left ventricular filling pressures
  • Rapid fluid shift from intravascular compartment into pulmonary interstitium and alveoli 2

This contrasts with "cold" pulmonary edema, which presents with peripheral vasoconstriction, cool extremities, and is typically associated with cardiogenic shock and reduced cardiac output.

Clinical Classification

According to the European Society of Cardiology guidelines, flushed pulmonary edema falls under the category of "hypertensive heart failure" within the clinical classification of acute heart failure syndromes 3:

• Characterized by signs and symptoms of heart failure accompanied by high blood pressure
• Relatively preserved left ventricular systolic function
• Increased sympathetic tone with tachycardia and vasoconstriction
• Patients may be euvolemic or only mildly hypervolemic
• Present frequently with signs of pulmonary congestion without signs of systemic congestion 3

Diagnostic Features

Key diagnostic features include:

• Acute onset of respiratory distress
• Bilateral pulmonary rales/crackles
• Orthopnea and tachypnea
• Warm, well-perfused extremities
• Normal or elevated blood pressure
• Chest radiograph showing bilateral interstitial edema
• Relatively preserved left ventricular ejection fraction on echocardiography
• Elevated natriuretic peptide levels

Management Approach

The management of flushed pulmonary edema focuses on rapid reduction of preload and afterload:

1. Vasodilator therapy:

   • Nitrates are first-line treatment (nitroglycerin starting at 5-10 mcg/min, titrating by 10 mcg/min every 3-5 minutes) 1
   • For severe hypertension, sodium nitroprusside may be considered (initial dose 0.1 μg/kg/min) 1

2. Diuretic therapy:

   • IV furosemide 40 mg injected slowly (over 1-2 minutes)
   • If inadequate response within 1 hour, dose may be increased to 80 mg 4

3. Non-invasive ventilation:

   • CPAP or BiPAP should be initiated promptly for patients with respiratory distress
   • Reduces work of breathing and improves oxygenation
   • Significantly reduces need for endotracheal intubation 1

4. Oxygen therapy:

   • Supplemental oxygen for SpO₂ <90% or PaO₂ <60 mmHg
   • Avoid routine oxygen in non-hypoxemic patients 1

5. Treatment of underlying cause:

   • Identify and treat any precipitating factors (e.g., hypertensive crisis, acute coronary syndrome)

Prognosis

Patients with hypertensive heart failure and flushed pulmonary edema typically have better outcomes compared to those with cardiogenic shock:

• Lower in-hospital mortality
• Patients usually discharged alive and frequently asymptomatic 3
• However, risk of rehospitalization remains high (almost half of patients within 12 months) 3

Common Pitfalls and Caveats

1. Overreliance on diuretics: While diuretics are important, vasodilators are equally or more important in the acute management of flushed pulmonary edema 2

2. Excessive fluid administration: Should be strictly avoided as it may worsen symptoms 1

3. Medication contraindications: Concomitant use of phosphodiesterase inhibitors (sildenafil, tadalafil, vardenafil) within 24-48 hours is contraindicated due to risk of profound hypotension 1

4. Monitoring requirements: Close monitoring of blood pressure during vasodilator therapy and non-invasive ventilation is essential to prevent hypotension 1

5. Differential diagnosis: Important to distinguish from non-cardiogenic pulmonary edema (ARDS), which requires different management approaches 3

Understanding the distinct pathophysiology and clinical presentation of flushed pulmonary edema allows for targeted therapy that can rapidly improve symptoms and outcomes in this specific subset of acute heart failure patients.