Liver Transplantation

Cold ischemic time for a donor liver

12-18 hrs

Surgical interruption of venous flow may decrease venous return to heart by___, reducing__ and causing____ SVR Results in?

50% CO increased subdiaphragmatic vessel engorgement, portal hypertension, and bowel congestion

Living donor liver transplantation (LDLT)

A living-donor liver transplant is a surgical procedure in which a portion of the liver from a healthy living person is removed and placed into someone whose liver is no longer working properly. The donor's remaining liver regrows and returns to its normal size, volume and capacity within a couple of months after the surgery. At the same time, the transplanted liver portion grows and restores normal liver function in the recipient.

What is a lymphocele

Defined as a collection of lymph in a cavity that is not lined by epithelium

Split Donation (Partial Graft)? example?

Is when a liver from a deceased adult donor is divided between two recipients The right lobe can be transplanted into most adults, and the left lobe can be transplanted into a child, since it is approximately the same size as a liver in a baby or a small child

Circuit similar to liver bypass circuit?

Left heart bypass

There are two very different surgical approaches to liver transplantation:

Orthotopic Approach Heterotopic Approach

What don't we need in the liver bypass circuit?

Oxygenator

Which vessels connect the capillary beds

Portal vessels

flows for establishing V-V bypass? anticoagulation? most frequent reason for decreased flows

•Experience indicates that flows should be at least one liter/minute. •Less flow seems to lower platelet counts, etc. (remember: no heparinization, and often patient has coagulopathy secondary to disease) •Malposition of cannula is most frequent reason for decreased flows

Steps for liver transplantation

•Graft insertion involves four vascular, and one biliary anastomoses •Suprahepatic and infrahepatic caval anastomoses made first •Portal vein is next, then flow is re-established •Hepatic artery is next, then biliary tract is reconstructed

Hepatic artery vs vein

•Hepatic artery (from aorta - oxygenated blood). ~ 25% of blood flow to liver. •Portal vein (from digestive tract/spleen, deoxygenated blood). ~ 75% of blood flow to liver

Located in _________quadrant of abdomen how many lobes

•Located in upper right quadrant of abdomen •Has 4 lobes, each dividing into lobules, which are the functional unit.

Most Crucial Times During Surgical Procedure: (times liver bypass may be utilized)

•Mobilization and removal of liver; and •Anhepatic phase •IVC and portal vein are occluded

Establishing V-V Bypass for transplant

•Portal vein is drained by cannula, often other sites drained (IVC, perhaps, to establish full venous return to heart if necessary). •Drained via bonded tubing to biohead, flow probe, back to patient at axillary vein/other central site in neck region •IVC is clamped distally •Liver pack for transplantation is pre-cut/assembled

Complications of Procedure v-v bypass

•Risks are air and thrombus embolization - delivered to lungs •Nerve damage •Lymphocele formation •Wound infection •Brachial plexus injury (~ 10 hr. procedure)

Which two veins converge to form the hepatic portal vein?

Superior mesenteric vein and Gastric vein

Transmedics Organ Care System (OCS) Liver

The OCS Liver is an FDA approved device for DCD (donation after circulatory death) and DBD (donation after brain death) donor Livers. Isolated allograft perfusion The OCS is designed to enable surgeons to transplant more organs from the available donor pool and to achieve better procedural outcomes

Why is V-V bypass helpful

V-V bypass seems to assist in post-op renal function, because less congestion is believed to assist renal function/recovery

Re-perfusion results in? causing?

acidic and potassium-rich venous blood flooding systemic arrhythmias

Relative contraindications for liver transplant

alcoholism or drug abuse, extra-hepatic malignancies, pre-existing local or systemic infections, advanced pulmonary or cardiac disease, other untreatable diseases.

Anhepatic phase

recipient is without a liver

Orthotopic Approach

replacing the recipient liver with the donor liver. After the donor liver is removed, preserved and packed for transport, it must be transplanted into the recipient within 12 to 18 hours

Heterotopic Approach:

the recipient's liver is left in place and a donor's liver is sewn into an ectopic site. Obviates the need for V-V bypass as the IVC will not require clamping. Sometimes called piggyback as the allograft is sewn in parallel to autograft.

Venous congestion may lead to

third-space fluid sequestration, possible peritoneal contamination with bowel flora, decreased renal function (hypoperfusion of kidneys secondary to venous congestion)

S & S of Liver Transplant Rejection

• Fever greater than 100° F • Jaundice - yellowing of the skin and eyes •Dark urine •Itching •Abdominal swelling or tenderness •Fatigue •Irritability •Headache

Most Common Complications: Liver Transplantation

•Acute graft rejection •Vascular thrombosis •Biliary leak or stricture •Infection •Malignancy •Adverse effects of immunosuppressant drugs

Most Common Causative Diseases for transplant

•Chronic active hepatitis •Cryptogenic (idiopathic) cirrhosis •Alcoholic cirrhosis •Isolated hepatic malignancy •Primary biliary cirrhosis •Acute hepatic necrosis •biliary atresia •Metabolic disease