For some reason, the college has decided to ask about this esoteric branch of transplant ICU on three separate occasions, with two identical questions:
It is difficult to determine exactly why this might have happened. One interpretation might be the fascinating physiology of the anhepatic patient, and the need to consider all the missing functions of the liver which one might need to support perioperatively. Assessment drives learning and preparing for the liver transplant SAQ would force the exam candidates to explore the topic of severe acute liver failure, an area which presumably would otherwise somehow go neglected. However, one might point out that the same could be achieved by asking a question about acute fulminant hepatitis due to the inadvertant ingestion of Amanita phalloides , or the much more common acute ischaemic hepatitis following cardac arrest, or a viral hepatitis, or something similar. Adult liver transplantation specifically is something performed at only five hospitals in Australia: RPAH in Sydney, The Austin in Victoria, Princess Alexandra in Brisbane, Flinders in Adelaide and Sir Charles Gardiner in WA. According to transplant.org 264 only liver transplants happened in Australia in 2015. As such, only a minority of the trainees will ever have any exposure to the process, as these units might only account for no more than 5% of the total training positions. Because of the pyramidal structure of the ICU medical hierarchy, the number of fully qualified specialists who would ever have to manage such a patient is even smaller. This makes the examiner's fascination with liver transplantation all the more puzzling, as being intimately familiar with it is clearly not something that discriminates a safe ICU specialist from an unsafe one. However, they keep asking these SAQs; and therefore the savvy CICM Part II candidate from a small regional centre still needs to become familiar with this topic in the event that it ever appears again in the written paper.
This is somewhat tricky. Usually, liver transplantation is accompanied by torrential blood loss. And as you keep filling the central compartment, it all leaks out again. Clearly, some sort of intelligent hemodynamic monitoring strategy is the key to success, with gradual incremental fluid and blood product replacement.
The stages of a liver transplant are traditionally called the "preanhepatic", "anhepatic" and "neohepatic" or "reperfusion" phases. Traditionally, the anhepatic phase of transplantation has been managed with an artifically low CVP (0-5mmHg). This prevents excessive blood loss from venous anastomotic sites as well as decreasing graft congestion. One good free article on this topic suggests that this is probably a bad idea on the grounds of increased renal morbidity, whereas another similar article supports this practice on the grounds of improved post-operative graft function. This is a fight among anaesthetists and one would be well advised to stay out of it. The pragmatic intensivist will merely want to know which war camp was in charge of anaesthetising their patient, to prepare for the ensuing renal failure.
Lastly, the "reperfusion" phase of the transplant is characterised by wild haemodynamic instability, as vasoactive products of anaerobic metabolism are flushed out of the donor liver by the first pulses of the recipient's blood. This could last all of 5 minutes, or it could last for many hours, well into their ICU stay. In this situation, one can manage things as if it were a SIRS response, using vasopressors.
The post-operative period is peppered by early complications, which are usually the only sort the intensivist will get to see. This has been well summarised in an excellent article from The Annals of Hepatology. I have added using Oh's Manual to form the table below:
Respiratory complications:
Circulatory complications:
Neurological complications:
Metabolic complications
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Renal complications
Graft-related complications
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There are several specific lung-related problems which occur following liver transplantation:
Two things could go wrong with the cardiovascular system:
These are managed without any transplant-specific strategies; vasopressor or vasodilator titration is no different.
The central nervous system gets hit as badly as every other organ system.
Metabolic and electrolyte abnormalities may develop, but to which extent is largely determined by graft health. These complications include:
Renal failure may complicate the recovery, as a result of
The graft itself could be the source of major problems:
Chapter 101 (pp. 1040) Liver transplantation by Anish Gupta, Simon Cottam and Julia Wendon
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