What is the management of deranged Liver Function Tests (LFTs) in an Intensive Care Unit (ICU) patient?

Management of Deranged Liver Function Tests in ICU Patients

The management of deranged liver function tests (LFTs) in ICU patients requires early identification of the underlying cause, prevention of aggravating factors, and supportive care of organ dysfunction to reduce morbidity and mortality. 1

Initial Assessment and Diagnostic Workup

Essential Diagnostic Tests

• Etiological workup:
  • Serum acetaminophen levels
  • Hepatitis A (IgM VHA) and Hepatitis B (HBsAg and anti-HBc IgM) serology
  • Urinary toxicology screen (amphetamine, cocaine)
  • Echocardiography and hepatic echo-Doppler 1

Laboratory Monitoring

• Complete blood count with platelets
• Comprehensive metabolic panel
• Coagulation profile (PT/INR)
• Arterial blood gas with lactate level
• Arterial ammonia level 1
• Monitor electrolytes, especially sodium and phosphate

Management Strategy by Organ System

Central Nervous System

• Monitor encephalopathy frequently
• Maintain serum sodium between 140-145 mmol/L
• Check blood glucose at least every 2 hours
• Consider tracheal intubation for progressive hepatic encephalopathy (Glasgow <8)
• Use transcranial Doppler ultrasound for monitoring instead of invasive ICP devices 1

Cardiovascular System

• Assess volume status, cardiac output, and cardiac function
• Use crystalloid fluids as first choice for fluid expansion
• Administer norepinephrine for refractory hypotension 1

Respiratory System

• Implement standard lung-protective ventilation strategies
• Avoid high levels of PEEP (>10 cmH2O) as this may cause hepatic congestion 1

Coagulation Management

• Restrict clotting factor administration to active bleeding or high-risk procedures only
• Recognize that most patients with liver failure have rebalanced hemostasis despite prolonged INR 1, 2
• Do not administer coagulation factors prophylactically as this masks disease progression 1

Renal System

• Implement renal replacement therapy according to standard recommendations
• Monitor regional citrate anticoagulation carefully if used during RRT due to potential metabolic effects 1, 2

Metabolic Management

• Correct hypoglycemia promptly (monitor glucose every 2 hours)
• Target sodium levels between 140-145 mmol/L
• Correct sodium abnormalities gradually (not exceeding 10 mmol/L per 24h) 1

What NOT to Do

1. Avoid sedatives and psychotropic drugs:

   • Do not administer benzodiazepines or metoclopramide 1
   • If sedation is necessary, minimize depth and duration 1

2. Avoid treatments to lower ammonia levels:

   • Do not use lactulose or rifaximin 1

3. Avoid nephrotoxic drugs:

   • Discontinue NSAIDs and other nephrotoxic medications 1

4. Avoid routine correction of coagulation:

   • Do not administer clotting factors prophylactically 1, 2

5. Avoid high PEEP ventilation:

   • Keep PEEP <10 cmH2O to prevent hepatic congestion 1, 2

Anticoagulation Considerations

• Use enoxaparin with extreme caution in patients with elevated INR (>1.5)
• Consider dose reduction (25-50%) for moderate to severe liver impairment
• Monitor for bleeding complications and consider anti-Xa levels if available 2
• Remember that anti-Xa monitoring may be misleading due to decreased AT-III levels 2

Prognostic Indicators

• Elevated arterial ammonia levels (>100 mmol/L) correlate with encephalopathy development and poor prognosis 1
• Blood lactate levels >3.5 mmol/L after 4 hours of management indicate poor prognosis 1
• Abnormal LFTs at admission are associated with increased risk of transfer to ICU, need for mechanical ventilation, and mortality 3, 4

Special Considerations

• Low-grade LFT abnormalities are common (61% of ICU admissions) and should not be disregarded 4
• LFT abnormalities often represent part of a spectrum of liver injury associated with critical illness 4
• Liver support devices have not demonstrated significant reduction in mortality and should not delay transfer to a liver transplantation center if indicated 1

By following this structured approach to managing deranged LFTs in ICU patients, clinicians can improve outcomes through early identification of underlying causes, prevention of aggravating factors, and appropriate supportive care.