Anesthesia for the patient undergoing liver transplantation

Published on 13/02/2015 by admin

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Last modified 13/02/2015

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Anesthesia for the patient undergoing liver transplantation

James Y. Findlay, MB, ChB, FRCA

Liver transplantation is an established therapy for end-stage liver disease, with the more than 6000 people who receive a liver transplant every year in the United States now having a 3-year survival rate of almost 80%. Despite recent advances in the use of living donors and of split-liver grafts for pediatric and adult recipients, the number of liver transplantations remains limited by the availability of suitable donors, with approximately 16,000 people waiting to receive a transplant. Liver transplantation presents a challenge to the anesthesia provider because, in addition to the operation being complex, most patients present for transplantation with greatly altered physiology because of their end-stage liver disease.

Preoperative evaluation

Table 176-1 lists some of the relevant physiologic consequences of liver failure and the consequences that may occur during liver transplantation. Prior to presenting for transplantation, candidates are screened for comorbid cardiopulmonary conditions: a resting echocardiogram assesses cardiac function and allows estimation of pulmonary artery pressures. A bubble test (injection of agitated saline while monitoring for echo-contrast in the right side of heart chambers) can also be performed; delayed appearance of the contrast agent suggests that the patient may have hepatopulmonary syndrome. If the patient has risk factors for coronary artery disease (∼40%-50% of adult patients), noninvasive testing is frequently performed, often by dobutamine stress echocardiography, because patients with significant coronary artery disease have poor peritransplant outcomes.

Table 176-1

Pathophysiologic Changes Associated with Liver Failure

Organ System Change Consequence(s)
Cardiovascular Hyperdynamic circulation (high cardiac output, low SVR)
Portal hypertension
Ascites
Pulmonary hypertension
Hypotension
Varices, splenomegaly
Bleeding (dilated vessels, thrombocytopenia)
Fluid shifts after drainage
High perioperative mortality rate (>80%) if severe
Respiratory Respiratory alkalosis
Restrictive physiology (ascites with or without pleural effusion)
Hepatopulmonary syndrome (intrapulmonary shunting)
Atelectasis; reduced compliance
Hypoxemia
Hematologic Decreased factor synthesis
Thrombocytopenia
Anemia
Bleeding potential
CNS Hepatic encephalopathy
Cerebral edema (in fulminant failure)
Delayed awakening
Raised ICP; consider ICP monitoring
Renal Hepatorenal syndrome
Hyponatremia
Renal failure—volume and electrolyte management concerns
Possibility of CPM if corrected intraoperatively

CNS, Central nervous system; CPM, central pontine myelinolysis; ICP, intracranial pressure; SVR, systemic vascular resistance.

Renal dysfunction often accompanies end-stage liver disease from hepatorenal syndrome, acute tubular necrosis, or a combination of both. In a patient requiring renal dialysis or continuous renal replacement therapy, consideration should be given to performing continuous dialysis or ultrafiltration in the operating room if problems managing volume or electrolytes are anticipated. Washing red blood cells prior to transfusion to reduce potassium may also be helpful.

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