Introduction

Nowadays, sickest patients are guided for LT and performed in patients who urgently need them due the policy of organ allocation according to MELD score system.

There are few data that influence how transplant anesthesia care is delivered. If anesthesia care had little effect on outcomes, it would not be important. However, there are some evidence that anesthesia care makes a significant difference on outcomes.

Preoperative Period
Any liver disease affects almost all organ system, especially neurologic, pulmonary, cardiovascular, renal and coagulation systems.

Intraoperative Period

Monitoring
Hemodynamic monitoring for recipient becomes even more important. However, the type of monitoring differs among transplant centers and is mainly determined by personal experiences or institutional practice.

Hemodynamic monitoring for LT usually includes at a minimum one arterial line and one central venous line. In addition, transesophageal echocardiography (TEE), or continuous cardiac output (CCO) has been described for advanced hemodynamic monitoring.

Dissection Phase
Blood loss during this phase of operation may be significant. Previous abdominal surgery or previous spontaneous bacterial peritonitis may make this phase of surgery more difficult and may cause significant bleeding. Therefore, intravascular volume management becomes more important in that phase. In these patients, blood salvage techniques can be useful and associated with a significant reduction in allogenic transfusion requirements.

Administration of blood products can be guided according to clinical findings or monitors of coagulation. Administration of fluid should be balanced between maintaining low CVP and adequate filling pressure. Although there is relatively evidence that lower CVP during liver surgery can reduce blood loss, the use of lower CVP in LT is still debated.

Liver diseases cause alterations in glucose metabolism. As a result of high dose steroid therapy hyperglycemia is common during the operation. On the contrary, hypoglycemia is the most important problem in patients undergoing LT due to fulminant hepatic failure. For that reason, strict plasma glucose monitoring becomes important issue throughout the operation.

Hypocalcemia and hypomagnesemia are frequently seen during LT. They all need to be corrected gradually because of altered clotting indices.

Anhepatic Phase
This phase is a unique period in LT surgery. In this period, the diseased liver is removed. Because of reduction in venous return and cardiac output by up to 50%, it is needed to support the circulation with a potent vasoconstrictor. Volume replacement therapy also is necessary. However, overtreatment of this condition with aggressive volume replacement can lead to hypervolemia at the time of graft reperfusion.

The important result of removal diseased liver is lactic acidosis due to exclusion of the native liver from the circulation. Thus, there is a rise in plasma lactate and decrease in plasma pH. This lactic acidosis is exacerbated when the graft liver is reperfused, and maximal acidosis and base deficit is therefore seen in the first several minutes after graft reperfusion. Thus, to treat the acidosis during the anhepatic phase to reduce the risk of severe acidosis with reperfusion may be useful in critical patients.

Neohepatic Phase
Vital role of anesthesiologists is to prevent high central venous pressure, which may cause graft congestion. Close communication about venous congestion of the graft and its color between the anesthesiologist and the surgeon has important role to optimize the graft survival.

At the begining of neohepatic phase, an acute clot lysis syndrome frequently develops. Thromboelastography demonstrates this pattern as typically graphic, which is poor clot initiation and rapid dissolution of clot, is called secondary fibrinolysis. Strategies for reducing fibrinolysis include use of antifibrinolytic agents such as tranexamic acid, and ε- aminocaproic acid.

At the end of the operation, the anesthesia team also prepares for the early extubation (i.e., in the operating room). Although it is reported that extubation rates varied from 5% to 80%, early extubation after liver transplant is often possible because of improvements in both surgical and anesthetic techniques. Its proponents argue that early extubation reduces the risk of pneumonia and improves both splanchnic and liver blood flow. Early extubation has been shown to decrease ICU length of stay and diminish resource use.

Postreperfusion Syndrome (PRS)
Despite improvements in the operative procedures of LT, PRS remains serious concerns for anesthesiologists. Even severe PRS may pose a direct threat to life during operation. Moreover, intraoperative PRS was associated with significantly higher intraoperative and postoperative mortalities and more frequent postoperative renal dysfunction. Incidence of PRS is 8-55%. The exact mechanism of PRS remains unknown, but the potential risk factors may include cold and acidotic components released from graft, severe graft ischemia- reperfusion injury, disorder of electrolyte and acid-base balance, and cirrhotic cardiomyopathy.

There are various suggestions to prevent or modify the severity of this syndrome including vasopressors, bicarbonate, ischemic preconditioning, calcium, methylene blue, N-acetylcysteine, and even flushing the graft with autologous blood.

Postoperative Period
All intraoperative modalities of monitoring and medication are continued in ICU. Early weaning from mechanical ventilation after LT is possible in selected patients with an uneventful intraoperative course. That does not only lower the risk of ventilator associated pneumonia but also improves the splanchnic and liver blood flow and reduces hepatic venous congestion. However fast tracking following LT is not a routine practice.

For postoperative care in liver transplant recipient, close collaboration between intensivist (anesthesiologist) and surgeon is needed. The main goals are hemodynamic stabilization, prevention of graft rejection and renal injury, and infection.