Saturday, November 27, 2010

Early Postoperative Period at Liver Transplantation

This lasts an average of 10 days and takes place in the intensive care unit. Supportive measures are taken as after any major surgical procedure; it is especially important to monitor adequate diuresis, as a good renal function will ease the use of cyclosporine. An attempt at lowering the incidence or severity of cytomegalovirus {CMV} infections is made by specific anti-CMV immunoglobulin infusions or with acyclovir. In high-risk situations, heparin is used to prevent hepatic artery thrombosis. Immunosuppression is started with i.v. methylprednisolone {10 mg/kg} and azathioprine {2 mg/kg} during the operation; i.v. cyclosporine is started postoperatively at increasing doses as soon as the hemodynamics and diuresis are satisfactory; azathioprine is discontinued when stable blood levels of cyclosporine are reached; methylprednisolone is progressively decreased down to 1 mg/kg per day at the end of the first week.

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A rise in serum transaminases is normally observed on days 1-3, followed by a rapid decrease to normal or near-normal values. Prothrombin time, often somewhat prolonged on day 1, also decreases regularly, a proaccelerin level above 50% is an carly indicator of good liver function.Four major complications may be observed during this period :
1. Primary graft nonfunction is rare, but of such severity that it requires emergency retransplantation.
2. Infections, mostly bacterial, are very frequent, but usually controlled by antibiotics.
3. Rejection is also frequent and usually occurs at the end of the first week. Liver needle biopsy is carried out as carried out as soon as rejection is suspected on clinical  or biochemical grounds, histological signs of rejection include portal tract inflammatory infiltrates, endotheliitis of the portal and centrilobular, veins, and/or periductular infiltrate with interlobular bile duct damage. Urgent therapy is needed, usually using three i.v. injections of methylprednisolone. Whenever this fails to control rejection, OKT3 monoclonal antilymphocyte preparation or FK-506 is given after checking the signs of persisting rejection by a repeat biopsy. Refractory rejection can lead to rapid or progressive liver cell failure and/or to a vanishing bile duct syndrome, which ultimately requires retransplantation.
4..Hepatic artery thrombosis is a major risk in children; it occurs in 10%-15% of cases with a much higher incidence when both donor and recipient are very young. Thrombosis is looked for daily by Duplex ultrasound and confirmed by arteriography. Emergency surgery may make it possible to remove the obstruction of the artery and to prevent necrosis of the liver or biliary complications secondary to ischemia of the biliary epithelium.

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