A man with alcoholic liver failure requires general anaesthesia for surgery. Anaesthetic agent of choice is:

A man with alcoholic liver failure requires general anaesthesia for surgery. Anaesthetic agent of choice is:

A. Ether
B. Halothane
C. Methoxyflurane
D. Isoflurane

Answer is D. Isoflurane

Chronic Alcoholism damages the liver and also induces enzymes involved in the metabolism of drugs. Hence, the response to drugs is not always predictable in a chronic alcoholic.

Ether, Halothane and Methoxyflurane are metabolised by the liver and hence would preferably be avoided in liver failure. 

Perioperative considerations in hepatic failure:

• Even in severe liver disease the problem is usually one of exaggerated effects of drugs on the CNS, rather than poor liver metabolism.
• Hepatic blood flow is altered by anaesthetic drugs (including alpha and beta agonists/antagonists), positive pressure ventilation, PEEP, and surgical technique.
• In most cases anaesthesia reduces hepatic blood flow, particularly if Halothane is used. However, Isoflurane may improve it.
• Regional techniques may be used as long as coagulation is not deranged, and it should be remembered that all local anaesthetics are metabolised by the liver.
• Isoflurane, Sevoflurane, or Desflurane are the preferred volatile agents as Enflurane, and particularly Halothane, have marked effects in decreasing hepatic blood flow and inhibiting drug metabolism.
  

 The following anaesthetic drugs are considered safe in liver failure:

• Premedication: Lorazepam. Midazolam and Diazepam can be used at a lower dose.
  
• Induction: Propofol, Etomidate and Thiopental
• Maintenance: Desflurane, Sevoflurane, Isoflurane, Nitrous Oxide. Enflurane may be used with caution. However, Halothane is contradicted because of the risk of hepatitis.
  
• Muscle Relaxants: Atracurium, Cisatracurium. Pancuronium, Vecuronium and Suxamethonium may be used with caution.
• Opioids: Remifentanil. Drugs that can be used with a reduced dosage are Fentanyl, Alfentanil, Morphine, and Pethidine.
• Analgesics: Paracetamol. NSAIDS, Lidocaine and Bupivacaine may be used with caution.

A powerpoint presentation on the said topic can be viewed at the following link:

Anaesthesia for patients with liver disease