Colloid Solution

Aka: Colloid Solution, Colloid Fluid Replacement, Albumin 5%, 5% Albumin, Albumin 25%, 25% Albumin, Hetastarch, Hydroxyethyl Starch, Dextran

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II. Definitions

  1. Colloid Solution
    1. Solution with incompletely dissolving particles, which create an osmotic force and attract water

III. Background

  1. Normal fluid state (maintained capillary plasma volume)
    1. Normal capillary hydrostatic pressure varies between 10 mmHg (near arteries) and 30 mmHg (near veins)
    2. Normal capillary osmotic pressure is 28 mmHg (primarily due to albumin), favoring fluid shift into capillaries
  2. Abnormal fluid states with capillary fluid loss and Interstitial Edema (e.g. Hypoalbuminemia)
    1. Fluid Shifts to interstitial space as capillary pressure exceeds capillary osmotic pressure
  3. Fluid effects
    1. Crystalloid infusions further decrease capillary osmotic pressure, increasing interstitial fluid
      1. For every liter of isotonic crystalloid infused, only 275 ml remains intravascularly
    2. Colloid fluid infusion related increased osmotic pressure either maintains capillary volume or increases it
      1. For every liter of colloid infused, only 700 ml remains intravascularly (~3 fold more than crystalloid)

IV. Preparations: Albumins

  1. Background
    1. Heat sterilized human Serum Albumin
    2. Albumin is preferred over other Colloid Solutions
  2. Albumin 5%
    1. Dose: 250 ml aliquot (expands plasma volume ~250 ml/aliquot)
    2. Osmotic pressure 20 mmHg
    3. Expands plasma volume 0.7 to 1.3 times the volume infused (maintained for up to 12 hours)
    4. May be beneficial in Fluid Replacement (e.g. Sepsis)
    5. Avoid in Traumatic Brain Injury
  3. Albumin 25%
    1. Dose: 50-100 ml aliquot (expands plasma volume 4 fold, with fluid pulled from intersitium)
    2. Osmotic pressure 70 mmHg (hyperoncotic)
    3. Limit to hypoalbuminemic states (NOT Hypovolemic Shock) due to Fluid Shifts out of interstitium
      1. Increased risk of Renal Failure and death in Hypovolemia
      2. Schortgen (2008) Intensive Care Med 34:2157-68 +PMID:18685828 [PubMed]

V. Preparations: Hydroxyethyl Starch (HES)

  1. Background
    1. Synthetic polysacharide chains resistant to enzymatic degradation
  2. Precautions
    1. Increased risk of Bleeding Diathesis (Factor 7 and vWF inhibition)
    2. Increased Nephrotoxicity Risk
  3. Hetastarch (5%)
    1. Osmotic pressure 30 mmHg
    2. Expands plasma volume 1.0 to 1.3 times the volume infused (maintained for up to 24 hours)

VI. Preparations: Dextran

  1. Background
    1. Glucose polymers produced by Leuconostoc Bacteria
  2. Precautions
    1. Increased risk of Bleeding Diathesis (Factor 7 and vWF inhibition), esp. at doses >20 ml/kg
    2. Increased Nephrotoxicity Risk
    3. Risk of Adverse Drug Reactions
      1. High rates of Anaphylaxis with older preparations (now rare)
  3. Dextran-40 10%
    1. Osmotic pressure 40 mmHg (hyperoncotic)
    2. Expands plasma volume 1.0 to 1.5 times the volume infused (maintained for up to 6 hours)
  4. Dextran-70 6%
    1. Osmotic pressure 40 mmHg (hyperoncotic)
    2. Expands plasma volume 1.0 to 1.5 times the volume infused (maintained for up to 12 hours)

VII. Precautions

  1. Do NOT use hyperoncotic Colloid Solutions in hypovolemic states
    1. Increased risk of Renal Failure and death as Fluid Shifts from the interstitium

VIII. Contraindications

  1. Traumatic Brain Injury
    1. Colloid Solutions are associated with increased mortality compared with crystalloid
    2. (2007) N Engl J Med 357:874-84 +PMID:17761591 [PubMed]

IX. Advantages

  1. Most colloid infused remains in the intravascular space for hours

X. Disadvantages

  1. Risk of sensitivity reactions
  2. Original studies in 1998 showed increased mortality with Colloid Solutions
    1. However, more recent studies have reestablished the safety of Colloid Solutions (e.g. 5% Albumin)
    2. (2004) N Engl J Med 350:2247-56 [PubMed]

XI. References

  1. Loflin (2015) Crit Dec Emerg Med 29(9): 11-18
  2. Marino (2014) ICU Book, p. 227-37

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