Human albumin : overview of general indications
Albumin is the most abundant plasma protein in the human body and has a wide range of physiological effects that have formed the basis for its clinical use in several diseases and pathological states
Albumin is a multi-functional protein with both colloidal and pharmacological activity .
Its physiological functions are summarized in Box 1 .
One of the key roles for albumin is its ability to bind with an array of endogenous ligands , including metabolites , lipids , hormones , metal ions and high-affinity endothelial cell albumin receptors , to facilitate transport , sequestration and transcytosis . 1 Furthermore , this capacity to bind endogenous ligands explains some of its non-oncotic physiological roles . For instance , albumin can modulate hemostasis through binding with nitric oxide , which exhibits vasodilator properties and anti-aggregating effects on platelets . 2
Albumin also affects bioavailability , transport and pharmacokinetics of numerous drugs by binding to these drugs . 3 For example , albumin administration results in increased effects of loop diuretics by augmenting drug delivery to the renal tubule . 4
One of the cardinal features of inflammation is an increase is vascular permeability with a consequent higher amount of albumin in the interstitial space . Moreover , a reduction in serum albumin is a marker for increased mortality risk . 5 Albumin appears to contribute towards the maintenance of the normal permeability of capillaries to macromolecules and solutes through an anti-inflammatory effect be mediated by inhibits the adhesion of human neutrophils to endothelial cells . 6
Finally , albumin plays an important antioxidant physiological role . In sepsis , for example , both reactive oxygen species ( ROS ) and reactive nitrogen species ( RNS ) exert their detrimental effect , in part through endothelial damage , with a negative impact on vascular tone , increased cell adhesion and vascular permeability . 7 Albumin contains 6 methionine and 35 cysteine residues , which contain sulfhydryl ( or thiol ) moieties and can trap multiple ROS and RNS . 8
Clinical uses for albumin Given that hypoalbuminemia is a known prognostic factor for adverse outcomes , it is not surprising that administration of albumin solution has been shown to reduce morbidity . 9 , 10 An overview of the FDA-approved indications for albumin is shown in Table 1 .
Sepsis A 2014 meta-analysis of the effect of crystalloids or albumin on mortality in adults with severe sepsis revealed a trend towards reduced 90-mortality in those given albumin compared with crystalloids ( odds ratio , OR = 0.88 , 95 % CI 0.76 – 1.01 , p = 0.08 ). 11 Furthermore , in a more recent meta-analysis , it was concluded that for patients with sepsis / shock ,
TABLE 1
FDA approved indications for
28 , 29 human albumin
• Shock ( major hemorrhage , acute hemorrhagic pancreatitis / peritonitis )
• Burns
• Pre- and postoperative hypoalbuminemia
• Hypoalbuminemia with oncotic deficit
• Acute respiratory distress syndrome
• Acute liver failure
• Ascites
• Acute nephrosis
• Renal dialysis
• Cardiopulmonary bypass
crystalloids were less efficient than colloids at stabilizing resuscitation endpoints . 12 In support of the value of albumin in sepsis , a recent pilot study demonstrated beneficial effect of albumin infusion on skin endothelial function that could be independent of its oncotic properties . 13 Finally , a 2020 economic modelling study concluded that albumin-based fluid support was a likely costeffective strategy in those with septic shock . 14
Current international sepsis guidelines recommend : “ Using albumin in addition to crystalloids for initial resuscitation and subsequent intravascular volume replacement in patients with sepsis and septic shock when patients require substantial amounts of crystalloids .” 15
In terms of how and when albumin should be administered in relation to crystalloids in patients with sepsis , a study has revealed how use of albumin less than 24 hours after crystalloid infusion , significantly prolonged intensive care unit survival . 16
As a resuscitation fluid Conditions such as hemorrhage , major surgery , sepsis and burns may result in fluid loss and require treatment to replace that lost fluid with a volume expander . 17 Typically , intravenous ( IV ) fluid is used for volume replacement and can be achieved with either crystalloids or colloids . 17 Crystalloids are widely used , although a disadvantage is that they have a short duration of action so that the intravascular volume increase is transient with rapid transfer of fluid to the extravascular tissue with an attendant risk of peripheral edema . 18 In contrast , due to the presence of high molecular weight compounds in colloids , their high oncotic pressure is thought to ensure that the fluid persists in
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