What is the role of albumin in treating low cardiac output?

Role of Albumin in Treating Low Cardiac Output

Albumin administration can be beneficial in treating low cardiac output when hypovolemia is present, but it should not be used as first-line therapy for all cases of low cardiac output syndrome.

Pathophysiological Basis

• Low cardiac output can result from various causes including hypovolemia, myocardial dysfunction, or increased systemic vascular resistance 1
• Albumin has several physiological properties that may benefit patients with low cardiac output:
  • Increases intravascular volume through its oncotic effects 1
  • Possesses anti-inflammatory and antioxidant properties that may improve hemodynamics 1, 2
  • Can counteract decreased cardiac output associated with certain conditions like hepatorenal syndrome 1

Clinical Indications for Albumin in Low Cardiac Output

Hypovolemic States with Low Cardiac Output

• In preterm infants with low cardiac output without cardiac dysfunction, albumin administration (20 ml/kg of 10% solution) significantly increases cardiac output and improves mean arterial blood pressure in hypotensive infants 3
• In patients with cardiogenic pulmonary edema presenting with hypotension and reduced plasma volume, 5% albumin solution can significantly increase cardiac output, mean arterial pressure, and cardiac work 4

Sepsis-Induced Low Cardiac Output

• In sepsis with low cardiac output associated with elevated systemic vascular resistance, guidelines recommend more common use of inotropes and vasodilators rather than albumin as primary therapy 1
• For fluid resuscitation in septic shock, crystalloids or albumin can be used for initial boluses of up to 20 ml/kg over 5-10 minutes to reverse hypotension 1

Cirrhosis and Hepatorenal Syndrome

• In patients with cirrhosis, albumin combined with vasoconstrictors (terlipressin or noradrenaline) improves systemic hemodynamics by increasing cardiac output through its volume-expanding effects 1, 5
• Albumin is administered at 1 g/kg before initiating vasoconstrictor treatment, followed by 20-40 g/day in hepatorenal syndrome 5
• Cardiac output increases significantly after albumin infusion in cirrhotic patients regardless of baseline diastolic dysfunction 6

Monitoring and Precautions

• Nearly one-third of cirrhotic patients receiving standard albumin infusion develop volume overload, particularly those with higher BMI and lower severity of liver disease 6
• Careful monitoring is essential when administering albumin, particularly in patients at risk for volume overload 1
• Parameters to monitor include:
  • Mean arterial pressure (target ≥65 mmHg) 1
  • Central venous pressure (8-12 mmHg) 1
  • Cardiac output 1
  • Vena cava oxygen saturation (target ≥70%) 1

Alternative Approaches for Low Cardiac Output

Inotropic Support

• Dobutamine is the first-choice inotrope for patients with low cardiac output in the presence of adequate left ventricular filling pressure and adequate mean arterial pressure 1
• Dobutamine infusion (up to 20 μg/kg/min) is recommended when myocardial dysfunction is suggested by elevated cardiac filling pressures and low cardiac output, or ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure 1
• The combination of dobutamine and noradrenaline is recommended as first-line treatment for stimulating both α1 and β2 adrenergic receptors in septic shock with low cardiac output 1

Vasopressors

• Noradrenaline is recommended as the first-line vasopressor when adequate intravascular filling fails to achieve a mean arterial pressure >65 mmHg 1
• In patients with low cardiac output and normal blood pressure, phosphodiesterase III inhibitors may be considered 1

Clinical Decision Algorithm

1. Assess for hypovolemia as cause of low cardiac output:

   • If hypovolemia present: Consider albumin (20 ml/kg) especially if patient is hypotensive 3, 4
   • If euvolemic or hypervolemic: Albumin is not indicated 1

2. For low cardiac output with adequate filling pressures:

   • First-line: Dobutamine infusion (up to 20 μg/kg/min) 1
   • Monitor response using SvcO2, myocardial function indices, and lactate levels 1

3. For low cardiac output with hypotension despite adequate volume:

   • Combination of dobutamine and noradrenaline 1

4. For specific conditions:

   • In cirrhosis with hepatorenal syndrome: Albumin (1 g/kg initially, then 20-40 g/day) plus vasoconstrictors 1, 5
   • In sepsis: Focus on inotropes and vasodilators rather than albumin alone 1

Prognostic Considerations

• Low serum albumin levels are independently associated with increased mortality in patients with chronic heart failure 7
• Hypoalbuminemia has emerged as an independent prognosticator in many cardiovascular diseases, including coronary artery disease and heart failure 2
• A decrease in albumin on follow-up is an independent predictor of increased mortality in heart failure patients 7