Liver Disease - Overview

Liver disease is a high-risk group for anesthesia

Classification system to assess risk

Ascites
Encephalopathy
Bilirubin
Albumin
Prothrombin time

Pharmacokinetics

Distribution

An unbound portion can be distributed widely; therefore, the volume of distribution (Vd) increases

Detoxification

Decreased hepatic clearance of drugs (benzodiazepines and opioids)

Elimination

Decreased biliary excretion

Other problems

Ascites: could decrease functional residual capacity (FRC)
Coagulopathy: decreased production of vitamin K clotting factors (II, VII, IX, X) and non-vitamin K (V, XI, XII, XIII) and altered platelet function 
Renal: hepato-renal syndrome and acute tubular necrosis. Increased plasma volume
Cardiac: high cardiac output and low SVR (severe)
Respiratory: V/Q mismatch reduces PaO2

Metabolic

Hypoglycemia and sodium retention

Neurology

Encephalopathy

Drugs

Corticosteroids

Assessment

Optimize condition by hepatologist

It may take several weeks (esp. nutrition)
CBC, electrolytes, clotting factors, LFTs, glucose, ABG
ECG, CXR & hepatitis B status
Vitamin K and mannitol may be needed pre-op

Conduct

Monitoring: CVP, arterial, capnography, urinary output, temperature, nerve stimulator, PAWP if severe myocardial abnormalities

Regional – could be the best option 
General - lower doses required: increased volume of distribution (Vd)
Careful titration of drugs, i.e., atracurium, sodium thiopental, and isoflurane
Increased FiO₂ and careful fluid balance
Perioperative mannitol to maintain urinary output
Avoid lactate and sodium fluids; give 5% dextrose
Warm pt adequately

Post-operatively

ICU may be required
Accurate fluid balance
Analgesia carefully
Risk of infection: prophylactic antibiotics