Liver Transplant I

Liver Transplants are complicated for many reasons. Not only is the liver an incredibly vascular organ, but it also filters blood returning from the abdominal organs through the splanchnic circulation. In patients with end-stage cirrhosis, the pressures in the splanchnic circulation is very high as the blood cannot be drained through the scarred liver. This portal hypertension greatly increases the bleeding risk. So how do you replace a liver when you have to detach all the vessels, which are under high pressure, and reattach them to a new liver? During this whole process, the surgeons have to clamp the vessels to work on them. Where do they clamp and how does that affect the body under anesthesia?

In the most standard version, the surgeons will clamp the inferior vena cava, which receives all the blood draining from the liver. However, doing so means that venous drainage from the lower extremities and abdomen ceases since the blood cannot get back to the heart. The patient may tolerate this temporarily, but as time goes on, that venous pooling starts accumulating evil humors, and when the clamps are released, the accumulated toxins flood the body. To ameliorate this, surgeons often do liver transplants with veno-veno bypass. They bypass blood from the femoral and hepatic vessels to the jugular or axillary vein where it can return to the heart by the superior vena cava. This tends to smooth the clinical course when the inferior vena cava clamps come off, but comes with its attendant risks.

When the surgery is this tricky, the anesthesia has to be delicate and careful. The liver transplant is a great example of how complex surgery affects what we do on the other side of the curtain. We have to plan for potential large bleeding if those portal vessels are injured, aid in the preparation for and management of veno-veno bypass, and prepare for arrhythmias, hypotension, hypothermia, and cardiovascular collapse when that all-important inferior vena cava clamp comes off.