Albumin…should we dig it, or ditch it?

Intro

I am always asked by vigilant ITU trainees of all grades, ‘should we give some albumin here; what do you think?’. In answer, my response is normally…no, it has no mortality benefit at all. But am I being harsh?

Physiology for dummies!

So albumin:

• Maintains the oncotic pressure (+ plasma volume) in blood vessels
• Transports drug molecules, bilirubin, steroid hormones in bloodstream
• Has a Half life approx. 20 days
• NORMAL plasma albumin range = 35-50g/L

HYPERalbuminaemia is caused, in the main by severe dehydration.

HYPOalbuminaemia however is caused by:

• Low synthesis of albumin in liver
• High break down of albumin (surgical and stress catabolism)
• High losses of albumin
• Malnutrition
• Chronically reduced liver function e.g. cirrhosis
• Redistribution of albumin – increase vessel permeability, leaking plasma proteins (sepsis)
• Burns
• Inflammatory response
• Haemorrhage -> hypovolaemia
• Increased urinary excretion e.g. nephrotic syndrome

 

Human albumin solutions are used for a range of medical and surgical problems, in burns and to volume replace in controversial situations. We have all seen it being splashed about on the gastro wards, particularly in patients with liver failure of varying degrees (perhaps more evidence based). However, Albumin sits in a controversial seat when it comes to treatment of shock and other conditions where restoration of blood volume is urgent.

In chronic illness, serum albumin concentration is inversely related to mortality risk. Each 2.5 g/L decrement in serum albumin concentration, risk of death increases by between 24% and 56% (Goldwasser 1997). Perhaps albumin in higher circulating quantities is protective – but natural self-synthesised stuff! Makes sense, it buffers changes in plasma pH (reducing metabolic acidosis) and it may reduce nitric oxide’s vasodilatory effect (maintaining organ perfusion). paper created a wash of excitement that this may be the solution to resuscitation in illness.

Human albumin solutions are expensive:

• Twice as expensive as HES
• 30 times more expensive than crystalloid solutions such as sodium chloride or CSL.

So it should only really be used where there is an absolute clinical indication!?

So…does it benefit patients at all? 

To assess the effectiveness and safety of human albumin solutions in the management of critically ill patients, particularly those with hypovolaemia from injury or surgery, burns and hypoproteinaemia, a systematic review of randomised controlled trials was conducted by the Cochrane team here

38 trials meeting the inclusion criteria and reporting death as an outcome. There were 1,958 deaths among 10,842 trial participants.

• For Hypovolaemia the relative risk of death following albumin administration was 1.02 (95% confidence interval (CI) 0.92 to 1.13). A lot here consisted of SAFE trial participants (75.2% of the information)
• For burns, the relative risk was 2.93 (95% CI 1.28 to 6.72)
• For hypoalbuminaemia, the relative risk was 1.26 (95% CI 0.84 to 1.88).
• The pooled relative risk of death with albumin administration was 1.05 (95% CI 0.95 to 1.16).

Most trials were small and many were poorly concealed, the results must therefore be interpreted with caution. The SAFE trial was a bit of a breath of fresh air from this angle however, randomising a huge 6997 randomised participants with good concealment. The SAFE trial provided no evidence that albumin reduced mortality in patients with hypovolaemia, although the possibility of a modest benefit or harm could not be excluded.

 

Summary

The bottom line is, as per SAFE; ‘consider human albumin (4-5% solution) for IV fluid resuscitation ONLY in patients with SEVERE SEPSIS’.

There is a lack of evidence to suggest that administering human albumin to critically ill patients will reduce their mortality rates, compared to administering other IV fluid  resuscitation fluids such as saline.

Considering a cost-benefit analysis, human albumin is more expensive to administer and has no apparent benefit to mortality compared to saline. So….I won’t use it really I guess, I can’t see how we can justify it.