Tasty Morsels of Critical Care 018 | Liver Transplant Part 1

11 Jan

Welcome back to the tasty morsels of critical care podcast.

Today we’re covering Oh’s Manual Chapter 103 looking at liver transplant.

There are two types of liver disease that might put you in line for a transplant

  • acute liver failure
  • chronic liver failure

I’ll confess before studying for my fellowships that I had a very poor understanding of the very important distinctions between acute and chronic liver failure. I can’t say I’m any expert on it now but it is a very important distinction to make.

As a result of the huge divergence between acute fulminant liver failure and chronic liver disease, you see transplant candidates presenting for transplant from the semi-stable out patient to the anhepatic wreck on a super urgent waiting list. Oh quotes that ~20% are in multi organ failure at the time of transplant. This is quite different from the other transplant populations who are generally temporized in some kind of stable ill health prior to being suitable for transplant.

As a result their ICU course can be fairly unpredictable and a touch dramatic at times.

To get listed, generally you have to have a >50% 5 year survival prediction at an MDT. And if you do get a liver, the 1 year survival is generally >90%. It can be difficult to predict the need for transplant in chronic liver failure but the MELD score is probably the best despite being originally designed to predict who would benefit from TIPS. Of note the MELD score should not be attempted manually given that its equation goes as follows

MELD = MELD(i) + 1.32 × (137 – Na) – [ 0.033 × MELD(i) × (137 – Na) ]

There are a variety of operative techniques surrounding the plumbing at transplant. The vascular supply and biliary tree need to be plugged in somewhere. Just pray your surgeon is a good artist in the op note. Split grafts can be common when a single donor liver is used for 2 recipients with some understandable complexity to the surgical technique when this is donw.

Of note don’t be surprised if they come back with some roux-en-y hepatojejunostomy as a means of attaching the graft biliary tree to the gut. This seems to be of modest relevance to the antimicrobial prophylaxis as connecting the upper GI tract more directly to the biliary tree might mean it is more likely to get bathed in fungi.

Expect them to return with a significant blood loss but do not expect any raised eyebrows till you get beyond the 5L point. They bleed. A lot.

As the graft gets reperfused lots of evil humours get washed out and around the recipient causing what can only be described as physiologic embarrassment of a great degree that can continue all the way into their ICU stay.

Their post op course will be determined by multiple factors, particularly the number of failing organs the recipient had prior to transplant. They may return extubated or they may return with all the machines and doo dahs turned up to 11. 

Like all transplants primary graft dysfunction is the initial worry and our best test for checking that the graft is working is probably a falling INR, but all the numbers should get better over time. Routine imaging of the biliary ducts and vessels is done within 24 hrs typically. Vascular thromboses are uncommon and Oh states that arterial thromboses are more common than venous ones though that has not been my own very limited personal experience. Biliary issues early are typically leaks. Either way problems with the ducts and dopplers tends to beget a 4 phase CT and often a return to theatre.

References

Oh’s Manual Chapter 103

Deranged Physiology

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