Is it necessary to switch to a plasma volume expander, such as albumin, after administering 1500 mL of crystalloid (intravenous) fluid?

Switching to Plasma Volume Expanders After 1500 mL Crystalloid

Switching to a plasma volume expander after 1500 mL of crystalloid is not routinely necessary in most clinical scenarios; crystalloids remain the first-line fluid for volume resuscitation, and the decision to add colloids should be based on specific clinical indications (sepsis with inadequate response, large-volume paracentesis >5L, or specific liver-related conditions) rather than an arbitrary volume threshold. 1, 2

General Principles of Fluid Resuscitation

Crystalloids as First-Line Therapy

• Isotonic crystalloids (preferably balanced solutions like lactated Ringer's or Plasma-Lyte) should be used as the initial resuscitation fluid in most patients at risk for or with acute kidney injury, shock, or hypovolemia. 1, 2
• Balanced crystalloids are preferred over normal saline to reduce the risk of hyperchloremic metabolic acidosis. 3, 2
• In sepsis, at least 30 mL/kg of crystalloid should be administered within the first 3 hours. 3, 2

When Crystalloids May Be Insufficient

The evidence shows that crystalloids are less efficient than colloids at achieving certain hemodynamic endpoints, but this does not automatically justify switching at a specific volume threshold. 4

• Central venous pressure and mean arterial pressure may be lower with crystalloids compared to albumin or other colloids. 4
• Crystalloid volumes required are typically 1.4 to 4 times higher than colloid volumes to achieve similar hemodynamic effects. 5, 6
• However, mortality outcomes favor crystalloids over hydroxyethyl starch (HES), with significantly lower all-cause and 90-day mortality. 4

Specific Clinical Scenarios Where Plasma Expanders May Be Indicated

Sepsis and Septic Shock

• Albumin may be considered when substantial amounts of crystalloids are required and the patient remains hemodynamically unstable (weak recommendation, low quality evidence). 3
• The decision should be based on inadequate hemodynamic response (persistent hypotension, poor tissue perfusion) rather than volume alone. 2
• Albumin is not recommended as first-line treatment and shows no definitive mortality benefit over crystalloids in sepsis. 1

Liver Disease and Paracentesis

• For large-volume paracentesis (>5 liters), albumin at 8 g/L of ascites removed is recommended to prevent post-paracentesis circulatory dysfunction. 5, 1
• For paracentesis <5 liters, plasma expansion is not necessary unless acute-on-chronic liver failure (ACLF) is present. 5
• Albumin is indicated for spontaneous bacterial peritonitis to prevent renal failure and reduce mortality. 1

Hypovolemic Shock

• If the patient is dehydrated, additional crystalloids must be given, or alternatively, 5% albumin should be used rather than 25% albumin. 7
• 25% albumin (hyperoncotic) may offer therapeutic advantages in oncotic deficits or long-standing shock where treatment has been delayed, but should be accompanied by appropriate crystalloids. 7

Critical Pitfalls to Avoid

Volume Thresholds Are Not Evidence-Based

• There is no evidence supporting a specific crystalloid volume (such as 1500 mL) as a trigger to switch to colloids. The decision should be based on clinical response, not arbitrary volume limits. 1, 2
• Continue fluid administration as long as hemodynamic parameters improve, using dynamic measures (pulse pressure variation, stroke volume variation) or static variables (blood pressure, heart rate, urine output). 2

Colloid-Related Risks

• Hydroxyethyl starches should be avoided due to increased risk of acute kidney injury and mortality, particularly in patients with pre-existing kidney disease or sepsis. 5, 3
• Albumin has been associated with harm in patients with traumatic brain injury and should be avoided in that setting. 1
• Albumin administration may cause pulmonary edema in some critically ill patients. 1

Cost and Availability Considerations

• Albumin is significantly more expensive than crystalloids (approximately 140 Euro per liter vs. 1.5 Euro for isotonic saline). 5
• Given similar efficacy for most indications, crystalloids should be preferred unless specific clinical scenarios justify colloid use. 5, 1

Practical Algorithm for Decision-Making

1. Start with balanced crystalloids (lactated Ringer's or Plasma-Lyte) for initial resuscitation. 3, 2

2. Assess hemodynamic response after each fluid bolus (250-500 mL increments after initial 30 mL/kg in sepsis). 3

3. Consider albumin only if:

   • Large-volume paracentesis >5L is performed (8 g/L ascites removed) 5, 1
   • Spontaneous bacterial peritonitis is present 1
   • Hepatorenal syndrome with appropriate volume status 1
   • Persistent hemodynamic instability despite adequate crystalloid resuscitation in sepsis (weak indication) 3

4. Monitor for fluid overload, especially in patients with chronic kidney disease who have limited ability to excrete excess fluid. 3

5. Initiate vasopressors (norepinephrine) if hypotension persists despite adequate fluid resuscitation, rather than automatically switching to colloids. 2