4. Clinical Guidelines for Liver Transplantation (PDF) - British ...

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4.2.5 TRANSPLANT PROCEDURE Guidebook for the Solid Organ Transplant Programme Chapter 4 The technical aspects of liver transplantation are complex. The procedure has been modified in many ways over the years to account for concerns regarding physiological stability during the transplant procedure and has been further modified to accommodate split liver, partial liver and living-related liver transplantation. The procedure is described as an orthotopic liver transplantation, which means replacing the liver in the same location in the body. The liver transplant actually requires four surgeries. These are listed as follows: i. Donor hepatectomy The liver is removed along with other organs, such as the heart, lung, pancreas and kidneys. Occasionally, the liver is split into two during this process and usually a portion of the organ goes to a child and the remaining liver goes to an adult. During this procedure, the anatomy of the donor is assessed and the liver is assessed for fat content, size and the presence of any tumors or abnormalities, which may affect the recipient operation. The organ can be kept in ice for up to 24 hours. However, the longer the storage time, the more likely there is going to be an ischemic reperfusion injury due to lack of nutrients and oxygen to the liver. Therefore, it is desirable to keep the cold ischemic time, i.e., the time the liver is stored on ice, as short as possible, preferably under 12 hours. ii. Recipient hepatectomy The recipient surgery is divided into three procedures: a. On entering the abdomen, the surgeon performs a careful assessment of the liver and other intra-abdominal structures. b. Rarely, an unexpected abnormality such as an advanced malignancy is found that precludes transplantation. A back-up recipient may then be brought in. c. The diseased organ is removed in a way that preserves vessels and the bile duct to permit re-anastomosis to the graft. The anesthesia for this particular procedure is quite complex. The patient requires intensive monitoring during the procedure. This requires a catheter in the radial artery at the wrist, in the central vein near the heart for monitoring pressures and for rapid infusion of fluids. The patient generally has compression devices on the legs to prevent blood clots from forming in the legs during the prolonged procedure. The entire chest and abdomen, armpit and groin are prepared should a venous bypass be required. Venous bypass allows flow of the blood from the inferior vena cava below the liver, which is normally clamped off during the operation, to leave the body, go through a pump and enter the body again above the liver. Patients who have heart disease or metabolic conditions, such as amyloidosis may not tolerate vena cava clamping during the procedure and may require a venous bypass. The venous bypass catheter takes blood from the saphenous vein in the groin and replaces it through the axillary vein in under the armpit. Therefore, incisions may be necessary in the groin and armpit when this procedure is performed. Chapter 4 – Clinical Guidelines for Liver Transplantation – July, 2010 Page 9 See Page 1 for disclaimer
Guidebook for the Solid Organ Transplant Programme Chapter 4 4.2.5 TRANSPLANT PROCEDURE CONT. iii. Back table preparation Before the liver is transplanted into the recipient, it is prepared in a separate location in the operating room. This is called the “back table preparation". The liver is inspected, perhaps biopsied, the anatomy is confirmed and any abnormalities, injuries or unusual findings detected and dealt with. The liver is modified to fit the recipient’s anatomy if necessary and the vessels and bile duct are optimized for transplant. iv. Transplantation Once the liver has been prepared in the back table, the diseased liver is removed and the transplant itself begins. There are two commonly used recipient procedures. One is the standard orthotopic procedure, which is generally used for patients with tumors and whole organ transplants, where the vena cava, the large vein that goes to the heart, is removed with the diseased liver. A second technique, termed “piggyback” technique is when the recipient’s vena cava is left intact, the liver is removed from the cava and the hepatic veins are sewn to the hepatic veins of the donor liver, leaving the patient’s vena cava as well as the transplanted vena cava intact. The first step of the recipient procedure is the anastomosis, the suprahepatic vena cava first, followed by the infrahepatic vena cava. The liver can be either washed out with cold lactated Ringers solution or some IV solution that washes out the potassium and preservative solution, or the patient’s portal blood can be run through the liver and allowed to run out the vena cava from below through a vent until such time that the liver has been washed out with the patient’s own blood. This blood is usually saved in a cell saver system, which scavenges any blood that is allowed to leave the body and is re-transfused once the red cells have been washed. This cuts down the need for allogeneic blood transfusions. Once the vena cava has been reconstructed, the portal vein is reconstructed, which when completed allows for reperfusion of the liver. The next procedure is to reconstruct the hepatic artery, which is done is various ways, generally not leaving too short of an artery or too redundant an artery. Good flow through the portal vein and hepatic artery is mandatory for survival of the organ. The quality of the storage can be assessed by the stiffness of the liver, the rapidity of preservation and the fact that the liver may make bile in the early reperfusion period. Livers that contain a lot of fat or were in storage for a prolonged period of time may function poorly at first. In the third stage of the operation, the bile duct is reconnected. If the biliary system of the recipient is adequate an intraoperative cholangiogram may be done to assess for major bile leaks or obstruction. The donor bile duct is sewn to the recipient bile duct so that the sphincter mechanism in the distal end is still intact. Sometimes a small stent is placed across the sphincter of Oddi to reduce the chance of a bile leak. The stent usually floats out on its own in the postoperative period but may have to be removed endoscopically. Chapter 4 – Clinical Guidelines for Liver Transplantation – July, 2010 Page 10 See Page 1 for disclaimer
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