A cute liver failure (ALF) results in diffuse cerebral dysfunction ranging from minor hepatic encephalopathy (HE) to coma, and disproportionately affects young, healthy adults. In these patients, neurological morbidity and mortality result from the development of cerebral edema and elevated intracranial pressure (ICP). (1) HE is potentially reversible with timely liver transplantation or spontaneous improvement in liver dysfunction, and prompt treatment of these patients can prevent death and improve outcomes. No single method can effectively identify patients at risk for cerebral edema. A high ammonia level should raise suspicion but on its own is not sufficient. (2) Monitoring of ALF patients for the development of cerebral edema and elevated ICP is fundamental to prevent death and improve outcomes. This review discusses the benefits and drawbacks of monitoring modalities and proposes a monitoring protocol.All patients with ALF should be closely monitored regardless of HE grade as patients can rapidly deteriorate. Stupor or coma can be due to severe HE, seizures, ischemic or hemorrhagic stroke, or impending cerebral herniation (1) ; and these etiologies cannot be distinguished without more advanced neuromonitoring. Elevated ICP occurs in up to 75%-90% of patients with high-grade HE (3) and is more common in patients with higher ammonia levels, renal failure, and a more rapid course. However, these are not absolutes, and without objective methods of neuromonitoring, patients may decompensate and develop elevated ICP without being noticed. Elevations in ICP can cause ischemic injury to the brain by lowering cerebral perfusion pressure and can lead to direct injury by herniation.A recent survey of liver transplantation sites revealed significant variabilities in monitoring ALF patients, reflecting the lack of evidence-based recommendations for neurological monitoring. (4) Further, significant fluid shifts can occur intraoperatively and postoperatively, which may precipitate elevations in ICP; and no guidelines exist for intraoperative neuromonitoring.(3) In one study of 22 patients with ALF who had ICP monitor placement, 82 episodes of elevated ICP occurred in 21 patients, with 5% occurring during the operative course and 20% occurring posttransplant.(3) Appropriate monitoring may prompt changes in standard operating room procedures such as positioning in a reverse Trendelenburg position, administration of hyperosmolar therapies, and, in rare cases, induction of hypothermia.
Neurological ExamsThe single most important monitoring modality in the low-grade HE patient is the neurological exam. HE usually begins with mild encephalopathy and frontal dysfunction. (1) As encephalopathy progresses, personality changes become more pronounced and level of consciousness decreases.Signs of elevated ICP include worsening level of consciousness, worsening pupillary light reflexes, and loss of