The incidence and prevalence of liver disease (particularly alcoholic liver disease and hepatitis C) is increasing in the developed world. In the UK, in 2006, 4450 people died from alcoholic liver disease, and deaths are increasing by 7% per year (1). Liver disease can be acute or chronic. Common causes of chronic liver disease are viral hepatitis (hepatitis B and C), autoimmune disease, and alcoholic liver disease. In the USA and the UK, acetaminophen overdose is the most common cause of acute hepatic failure, while worldwide it is viral hepatitis (2). Despite the diversity of the causes of liver disease, the outcome after anesthesia and surgery depends more on the degree of liver impairment than the actual cause. Patients with end-stage liver disease are at significant risk of morbidity and mortality after anesthesia and surgery, and thus present unique challenges for the anesthesiologist.
Preoperative assessment of patients with liver disease should focus on the extent of liver dysfunction and extra-hepatic complications (1). A full blood count will detect anemia, thrombocytopenia, or raised white cell count if infection is present. Prothrombin time (PT) is a useful indicator of hepatocellular function and is used as a prognostic indicator in acute liver failure and after surgery in patients with chronic liver disease. However, PT may be elevated independent of liver function in patients with vitamin K deficiency, disseminated intravascular coagulation, or warfarin therapy. Where possible, vitamin K should be administered for several days before operation (1). Baseline renal function should also be determined and severe hyponatremia or potassium abnormality corrected before surgery. Cardiac investigations should include ECG and echocardiography, if risk factors for left ventricular dysfunction, cardiomyopathy, valvular lesions, or pulmonary vascular pathology are present. If significant coronary artery disease is suspected, an exercise ECG, dynamic assessment of left ventricular function, or both may be helpful. Chest X-ray or ultrasound may be useful for demonstrating pleural effusions in need of drainage before operation. Lung function tests can be helpful to delineate any restrictive or obstructive pulmonary disease. An important measure for assessing mortality risk is the Child-Pugh Classification (2). A total score of 5 or 6 is considered Child’s class A and is associated with a low operative mortality risk (<5%); a total score of 7–9 (Child’s class B) carries a moderate risk (25%) and total score of 10–15 (Child’s class C) carries a high risk (>50%). Although this classification was first used to stratify risk for surgical correction of portal hypertension, it has also been found to be predictive of survival in cirrhosis (2).
It is generally accepted that the risk of surgery cannot be isolated from the risk of anesthesia. The choice of drugs for anesthesia induction and maintenance is less important than the care with which they are used. With that said, volatile anesthetics such as isoflurane, sevoflurane, and desflurane undergo minimal hepatic metabolism and can be regarded as safe. Desflurane is probably the ideal volatile agent, being the least metabolized and providing the quickest emergence from anesthesia (3). If using intravenous anesthetic agents, the dose of thiopental should be reduced because a reduction in plasma proteins results in an increased unbound fraction of drug; the distribution half-life and consequently the duration of action are also prolonged. Sensitivity to the sedative and cardiorespiratory depressant effects of propofol is increased; hence the dose should be reduced (2). Lastly, opioids have also been used successfully in patients with liver disease. However, certain pharmacological consequences such as delayed drug clearance and prolonged half-life should be considered. Fentanyl is considered the opioid of choice in these patients because when used in relatively moderate doses, it does not decrease hepatic oxygen and blood supply, nor does it prevent increases in hepatic oxygen requirements (3).
Postoperative ICU admission should be anticipated for patients with advanced liver disease. In some circumstances, postoperative artificial ventilation may be appropriate, but in general, sedative drugs should be discontinued early and patients allowed to recover from anesthesia so that neurological assessment can be performed. Worsening encephalopathy, jaundice, and ascites are very important clinical markers of decompensation of liver function (2). Invasive cardiovascular monitoring and careful fluid management is continued to avoid the development of postoperative renal failure. Monitoring of coagulation and also maintaining vigilance for signs of postoperative bleeding should be continued. Intravascular catheters should be removed as soon as they are no longer needed because of the increased risk of catheter-related sepsis (1).
References
- Rakesh Vaja, Larry McNicol, Imogen Sisley, Anaesthesia for patients with liver disease, Continuing Education in Anaesthesia Critical Care & Pain, Volume 10, Issue 1, February 2010, Pages 15–19, https://doi.org/10.1093/bjaceaccp/mkp040
- Aparna Dalal and John D. Jr. Lang (February 13th 2013). Anesthetic Considerations for Patients with Liver Disease, Hepatic Surgery, Hesham Abdeldayem, IntechOpen, DOI: 10.5772/54222. Available from: https://www.intechopen.com/books/hepatic-surgery/anesthetic-considerations-for-patients-with-liver-disease
- Rahimzadeh P, Safari S, Faiz SH, Alavian SM. Anesthesia for patients with liver disease. Hepat Mon. 2014;14(7):e19881. Published 2014 Jul 1. doi:10.5812/hepatmon.19881