Timing for transplantation is very important, but unfortunately there are no absolutes to use as guides. Like the TV show "The Price is Right" where contestants try to guess as close as possible to the price without going over, one would like to wait as long as possible before doing a liver transplant, without waiting too long.

One must always keep in mind that a liver transplant involves removing the child’s own liver. From that moment on the child will be completely dependent on the donor liver. It’s too late to decide that child was actually better off with their original liver. Unlike kidney failure and heart failure, there is no artificial means of support if the new liver doesn’t do its job. While scientists are trying to develop an artificial liver, to date there is no system that performs the complex functions of a human liver reliably.

In general, if a child can live much longer (a year or more) without a transplant and still have as good a chance at survival, then a transplant would be too early. On the other hand, one waited too long if something happens which decreases the chance of survival after the transplant. Unfortunately, there is no accurate way to predict when such events will take place. As a child’s liver disease gets worse and worse it becomes easier to predict what will happen, but there is still no way to be accurate.

Some children will have good quality of life for many years with "compensated" liver disease, while others will not. For example in the case of biliary atresia, some children need a transplant within the first year of life, some not until elementary school age, and some not until adolescence or even into adulthood.

Compensated liver disease is when the disease exists but there are either few symptoms, or the symptoms are mild and stable. Decompensation is when a new and dire set of symptoms appears, especially if these new symptoms cannot be effectively treated. For example, a child with liver disease may develop ascites which can be effectively treated with a diuretic (water pill). The child is then said to have compensated liver disease. If after months to years the ascites suddenly will not go away even if diuretics are used, this would be decompensation. Patients are referred for transplant when they begin to show signs of decompensation.

Not every physician will agree on who is compensated and who isn’t. Like the terms "mild" and "severe," the terms compensated or decompensated are not the same in everyone’s eyes. Your physician should answer this question individually for your child, based upon his or her own experience and medical judgment.

Certain signs portend a bad prognosis, meaning that death from liver failure is likely within a year. These signs include encephalopathy, spontaneous bacterial peritonitis (SBP), and profound coagulopathy.

Encephalopathy is when the liver can no longer clear the wastes in the blood. These wastes build up and cause first a sort of sleepiness, then more profound lethargy and eventually coma.

SBP is when fluid called "ascites" collects in the abdomen, and this fluid gets spontaneously infected. It is thought that the infection may come through the walls of the bowels. The symptoms usually include abdominal pain and fever, but not always. Sometimes SBP will cause encephalopathy and this will be the only symptom.

Coagulopathy is when the blood fails to clot normally. The liver synthesizes the proteins in blood which cause blood to clot. When the liver isn’t making enough of the protein "factors," the patient has coagulopathy. Coagulopathy is measured by the pro-time (PT). When the PT is longer than normal (usually about 10 seconds is normal), the patient has coagulopathy.

In general, if the child’s overall health is not getting any worse, it is usually better to wait. But if they are not growing, or if they are having trouble with encephalopathy or ascites, and they are certain to continue to get sicker, they should be transplanted as soon as possible. It is always better to transplant before the child becomes very ill and needs an urgent graft. Urgent transplants always have worse success rates.

Some patients require transplantation even if their liver is functioning well. Examples include patients with tumors that cannot be removed without removing the entire liver, and children with certain diseases of metabolism due to inherited diseases. In these cases, the term "compensation" doesn’t really apply to their problem and their circumstance require unique considerations.

Fortunately, most children get the livers they need before they become critically ill. Living donor liver transplants (LDLT) continue to play an important role in solving the problem of timing. LDLT can be scheduled before the child becomes so sick their chances for a successful transplant are diminished. However, LDLT is not always the best option. As of 1998, the overall results for LDLT appears to be at least as good, if not better, for babies and small children compared to grafts from deceased donors (cadaveric grafts). But for larger children (over 40 pounds), the results for cadaveric grafts are at least as good if not better. For children who are nearing adult size (75+ pounds), the results for living donor grafts still looks to be inferior compared to cadaveric grafts. Different programs and doctors have different opinions regarding the issue of LDLT and the state of the art is constantly changing.

Dr. Punch is an assistant professor of surgery at the University of Michigan and member of the C.L.A.S.S. Scientific Advisory Committee.