Chapter 91: ICU Management in Liver Transplantation

ICU MANAGEMENT

• Early postoperative recovery after liver transplantation occurs in the intensive care unit (ICU).

• A fast-tracking option is available in certain institutions and includes coordinated operating room, postoperative recovery unit, and specialized ward management with a high-level nursing staffing ratio (e.g., 1:1 during the early postoperative recovery period).¹

• The early postoperative period is driven by emergence from general anesthesia, recovering multiorgan dysfunction, and establishing liver graft function.

NEUROLOGIC SYSTEM

• Pain^2,3

  • Results in elevated catecholamines with resultant delirium, myocardial ischemia, and hypercoagulable state

  • Commonly used behavioral pain scales include the Behavioral Pain Scale (BPS) and the Critical Care Pain Observation Tool (CPOT)

  • Opioids are the mainstay analgesics: short-acting fentanyl and remifentanil, as well as longer-acting hydromorphone and morphine

• Sedation^2,3

  • Consists of anxiolysis, hypnosis, and amnesia

  • Indicated for patient comfort and to facilitate mechanical ventilation

  • Daily interruption of sedation or light sedation reduces duration of mechanical ventilation and ICU length of stay

  • Commonly used scales to assess level of sedation are the Sedation-Agitation Scale (SAS) and the Richmond Agitation-Sedation Scale (RASS). RASS can be used across the entire spectrum of sedation and agitation.

  • Provided by benzodiazepines, propofol, and dexmedetomidine

  • Benzodiazepines (midazolam and lorazepam)

    • Associated with development of delirium

    • Accumulate in fat stores with delayed awakening

    • Patients with history of alcohol abuse may require higher doses

  • Propofol

    • Causes hypotension, decrease in intracranial pressure, decrease in cerebral perfusion pressure

    • Side effects include infection, hypertriglyceridemia, and pancreatitis

    • Propofol infusion syndrome is a rare life-threatening complication resulting from block in fat oxidation with resultant lactic acidosis. More common when high dose (>50 mcg/kg/min) infusion for prolonged period in setting of critical illness, shock, and steroid use

  • Dexmedetomidine

    • Hepatically eliminated

    • Does not cause amnesia

    • Allows for serial neurologic evaluation

    • Adverse reactions include bradycardia and hypotension

• Delirium^2,3

  • Associated with increased mortality, prolonged length of stay in the hospital and ICU, and post-ICU cognitive impairment

  • Involves (1) acute change or fluctuation in mental status and (2) inattention with either (3) altered level of consciousness or (4) disorganized thinking

  • Practical diagnostic approach involves using the Confusion Assessment Method for the ICU (CAM-ICU) in conjunction with the RASS (Fig. 91-1)

  • Prevention involves avoidance of deep sedation, early mobilization, and promoting a structured sleep–wake cycle

  • Atypical antipsychotics (quetiapine, olanzapine) may reduce the duration of delirium. When used, the QTc interval should be monitored to avoid torsades de pointes.

  • Dexmedetomidine is the preferred agent for sedation in patients with delirium

• Hepatic encephalopathy

  • Characteristic of acute liver disease

  • Ammonia metabolism is implicated in the pathophysiology

  • Postoperatively, the presence or absence of hepatic encephalopathy reflects liver graft function

• Cerebral edema

  • Severe manifestation of hepatic encephalopathy in acute liver failure

  • Results in intracranial hypertension

  • Management includes avoiding hypoxemia, hypotension, and hypothermia; sedation to reduce cerebral metabolic rate; hyperosmolar therapy (mannitol, hypertonic saline); hyperventilation (PACO₂ = 30 to 35 mm Hg); and decompressive craniotomy