What is the role of albumin in managing a patient with a low cardiac index post heart surgery?

Albumin for Low Cardiac Index Post Heart Surgery

Albumin is not recommended for routine use in managing low cardiac index after heart surgery as it does not improve mortality, renal function, or cardiac index compared to crystalloids, and may increase risks of bleeding, resternotomy, and infection. 1

Evidence Against Routine Albumin Use

• A systematic review and meta-analysis of 43 randomized studies (N=3,862) found that albumin infusion did not result in lower mortality rates compared to other fluids in cardiac surgery patients (risk difference 0.00; 95% CI -0.01 to 0.01) 1
• No differences were found in cardiac index (MD 0.07 L/min/m²; 95% CI -0.10 to 0.25 L/min/m²) when comparing albumin to alternative solutions 1
• The Albumin in Cardiac Surgery (ALBICS) trial of 1,386 patients showed that albumin significantly increased the risk of major bleeding, resternotomy, and infection compared to Ringer's acetate 1
• International guidelines strongly recommend against routine use of albumin for priming the cardiopulmonary bypass circuit (Strong recommendation, moderate quality evidence) 1

Potential Benefits of Albumin

• Albumin may reduce the risk of myocardial injury in some cardiac surgery patients, though this benefit is outweighed by other risks 1
• Albumin use results in a lower fluid balance compared to alternative solutions (MD -0.55 L; 95% CI -1.06 to -0.40 L) 1, 2
• A small study of 100 post-cardiac surgery patients found that 20% albumin was associated with less positive fluid balance and decreased median overall dose of norepinephrine compared to crystalloid 3

Hemodynamic Effects of Albumin

• In post-cardiac surgery patients, mean arterial pressure (MAP) response to 20% albumin fluid bolus therapy occurs in approximately 55% of patients but dissipates within minutes 4
• Cardiac index (CI) response to albumin is not congruous with MAP response, with CI response occurring in only 25% of patients initially, increasing to almost 50% over 30 minutes 4
• The FDA label indicates that albumin is hyperoncotic and expands plasma volume by three to four times the volume administered, but this does not translate to improved cardiac index in cardiac surgery patients 5, 1

Prognostic Value of Albumin Levels

• Low postoperative serum albumin levels after cardiac surgery are associated with increased in-hospital mortality (OR: 0.84; 95% CI: 0.80-0.84) and reduced long-term survival 6
• Preoperative measurement of albumin is recommended for risk stratification before cardiac surgery (class IIa, level C-LD) 1
• However, while low albumin levels have prognostic value, this does not necessarily mean that albumin administration improves outcomes 7, 6

Alternative Approaches for Low Cardiac Index

• For low cardiac output with adequate filling pressures, dobutamine infusion (up to 20 μg/kg/min) is recommended as first-line treatment 8
• For low cardiac output with hypotension despite adequate volume, a combination of dobutamine and norepinephrine is recommended 8
• Careful monitoring of parameters including mean arterial pressure, central venous pressure, cardiac output, and vena cava oxygen saturation is essential when managing low cardiac index 8

Clinical Decision Algorithm

1. Assess volume status first - ensure adequate preload before considering inotropes 8
2. If low cardiac index persists despite adequate volume:
   • First-line: Dobutamine infusion (up to 20 μg/kg/min) 8
   • For concurrent hypotension: Add norepinephrine 8
3. For fluid resuscitation, prefer balanced crystalloid solutions over albumin 1, 9
4. Monitor for fluid overload and adjust therapy based on hemodynamic response 8, 4

Pitfalls and Caveats

• Despite common use of albumin in cardiac surgery, there is little evidence supporting its use to improve patient outcomes 1
• Albumin is more expensive than crystalloids without providing clear clinical benefits 2
• In surveys, while many practitioners use albumin to minimize positive fluid balance, over 90% felt it did not reduce mortality, renal injury, or coagulopathy 1
• The FDA label lists cardiopulmonary bypass as an indication for albumin, but current evidence and guidelines do not support this practice 5, 1