Systems04 Gastrointestinal Gg4 Syndromes Diseases

Liver Failure

Last modified: 07 November 2022, 3:33:23 PM AEDT

Gems / Priorities1 / 14

fibrinogen an important marker of coagulopathy
anaesthetic challenges
- multiple comorbidities (eg. alcohol ⮕ alcoholic cardiomyopathy)
- F = disordered fluid + electrolyte balance
- H = coagulopathy
- I = infection risk
- P = altered drug metabolism
key determinant of perioperative M+M is portal HTN (presence + severity)
- not assessed directly by CTP (Child Pugh score)

Definition / diagnostic criteria2 / 14

cirrhosis
- anatomical diagnosis
- architectural distortion as a consequence of advanced liver fibrosis
- histology
  - diffuse hepatic fibrosis
  - normal liver architecture replaced by nodules

Classification3 / 14

Child-Pugh / Child-Turcotte Pugh Score
- first described by Child and Turcotte 1964
- modified by Pugh 1973
MELD = Model for End-stage Liver Disease
- Initially called Mayo End-Stage Liver Disease
- devised to estimate mortality for TIPS
- now used for prognostic marker in many liver conditions
- but primarily for transplant planning
- 3.78 x ln bilirubin + ln 11.2 INR + ln 9.57 Cr + 6.43
- Bili + INR + Cr
- Maximum MELD = 40
MELD 2016
- Also Na and dialysis (2/week)
- Use Cr 350 (4.0) if
  - Cr > 4.0
  - 2+ dialysis / week
  - 24 hours of CVVHD in last 7 days
- MELD > 20 = mortality > 50%
- OPTN = Organ Procurement and Transplantation Network
- UNOS = United Network for Organ Sharing
- New MELD score in 2016 = uses different model to MELD-Na
- Recalculated if initial MELD > 11 incorporating Na value
- https://optn.transplant.hrsa.gov/media/1575/policynotice_20151101.pdf
A = Albumin < 28
B = bilirubin > 50
C = Coagulopathy = INR > 2.2
D = Distension = Ascites (marked)
E = Encephalopathy (marked)
low risk
- Child-Pugh A
- MELD < 10
Risk stratification (GESA 2014)
- CTP
- MELD
- ASA
Mayo Postoperative Mortality Risk Score

Epidemiology4 / 14

Overview
Incidence
- NAFLD most prevalent liver disease in Australia
- 40% adults 50+
Prevalence
Gender

Prognosis5 / 14

periop mortality 10%
periop complications 30%
- especially pneumonia
mortality (abdominal surgery)
- Class A = 10%
- Class B = 30%
- Class C = 70%
  - Avoid / delay until after liver TX

Aetiology / Causes / Risk Factors6 / 14

3 biggest causes
1. NAFLD = Non-alcoholic fatty liver disease
2. HCV / HBV
3. Alcoholic liver disease
All causes
- Infection
  - HCV = IV drug use, tattoos, blood transfusion, overseas travel
- Drugs
  - toxins = alcohol, herbal remedies
  - drugs = isoniazid, paracetamol, phenytoin
- pregnancy = HELLP, AFLP
- malignancy: infiltration, portal vein thrombosis
- ischaemia = shock

Complications7 / 14

B = Respiratory
- impaired gas exchange / lung disease
- ascites ⮕ ⬇FRC / restrictive lung disease
- HPS = hepatopulmonary syndrome
  - marked pulmonary vasoD = ⬆BQ ⮕ intrapulmonary SHUNT and V/Q mismatch
  - result = mild/moderate hypoxaemia
  - orthodeoxia = PaO2 is worse on upright compared to supine
  - platypnea = dyspnoea that is worse on upright compared to supine
  - usually resolves after TX
- PPHTN = portopulmonary hypertension
  - pulmonary vasoC + PHTN from metabolites causing vasoC = PHTN
  - does not usually resolve after TX
C = Cardiovascular
- hyperdynamic circulation = ⬇SVR, ⬆CO
- cardiomyopathy from vitamin deficiences / alcohol
D = Neurological
- encephalopathy
  - ⬇metabolism of NH3 by hepatocytes
  - NH3 crosses BBB ⮕ glutamate + NH3 ⮕ glutamine in astrocytes
- ⬆osmotic pressure ⮕ ⬆intracellular volume ⮕ cerebral oedema
E = Endocrine
- hypoglycaemia
  - ⬇GNG,
  - ⬇insulin uptake by hepatocytes ⮕ ⬆peripheral insulin
F = Renal
- renal failure = hepatorenal syndrome
  - vascularisation of hepatic sinusoids
  - intra-hepatic shunting + ⬆NO + ⬇SVR + RAAS++
  - 20% patients, esp in decompensated cirrhosis
  - renal vasoC with hypoperfusion, due to extended splanchnic vasoD
  - treat with terlipressin (splanchnic vasoC) + albumin
- metabolic acidosis
- ⬆total body water, intravascular volume depletion (⬇albumin)
G = GIT
- portal hypertension
  - ⬆resistance to BQ ⮕ ⬆pressure in portal venous system
  - portosystemic varices + variceal haemorrhage
    - oesophageal
    - rectal
- ascites
  - portal HTN, salt + water retention, ⬇albumin
- cholecystitis
- pancreatitis
H = Haematology
- thrombocytopenia
  - liver failure ⮕ portal HT ⮕ hypersplenism ⮕ splenic sequestration
  - ⬇thrombopoietin levels
  - immune-mediation destruction
- ⬇synthesis of clotting and inhibitory factors, as well as decreased clearance of activated factors
- ⬆fibrinolysis
I = Immune
- ⬆bacterial translocation from GIT
- poor wound healing

Symptoms / History8 / 14

weakness and fatigue
jaundice
abdominal pain / swelling
altered mental state
pruritis

Signs / Examination9 / 14

General inspection

jaundice
malnourished
clues to cause
- tattoos = HBV / HCV
- pigmentation = haemochromatosis
constructional apraxia = hepatic encephalopathy

Hands

palmar erythema
bruising
asterixis / flap = hepatic encaphalopathy

Chest

spider naevi
gynaecomastia

Head

jaundice = yellow sclera
fetor = sweet breath

Abdomen

inspection
- masses
- distension
- bruising
- scars
palpation
- hepatomegaly
  - massive, firm, tender, irregular, pulsatile
- splenomegaly
  - can roll patient onto right side
- kidneys
percussion
- liver span
- ascites
  - shifting dullness
    - percuss
    - roll
    - percuss
ascultatation
- bruits
- friction rubs
- bowel sounds

Investigations10 / 14

Ascitic tap
- cytology
- microscopy
- culture
- biochem
Bloods
- EUC
- serum ammonia
- LFTs
  - transaminases
  - bilirubin
  - albumin
  - blood glucose
- Coags
Liver biopsy
FibroScan = liver stiffness by transient elastography
blood proteins, eg. FibroTest = alpha-2 M, haptoglobin, apo-A1, GGT, bilirubin

Management11 / 14

Supportive therapy
NAC infusion = equivocal evidence
Treat encephalopathy
- Lactulose, rifaximin
Nutrition
- high calorie, low-protein enteral feeding
Procedures
- protein and fluid restriction
- gastroscopy
- injection of varices
- portocaval shunt

Anaesthetic considerations12 / 14

Pre-op
- optimise
  - C = coagulopathy
  - D = encephalopathy
  - F = fluid status
  - F = treat EUC/AB abnormalities
  - G = consider draining ascites to improve respiratory mechanics
- avoid elective surgery
  - acute hepatitis
  - high risk patients = CP C / MELD 20
- classify
  - assess for cirrhosis
  - score CP + MELD
Intra-op
- caution drugs
  - sedatives, opioids
  - Limit paracetamol to 2 g/day
  - drug dosing
    - ⬇dose drugs with hepatic metabolism
    - ⬆dose NMBA in cirrhosis (⬆Vd)
- G = maintain HBF
  - avoid hypocarbia (⬇HBF)
- F = maintain renal function
  - adequate intravascular volume + CO
  - avoid nephrotoxins, including NSAIDS
Post-op
- B = ventilate if prolonged surgery / haemorrhage / hypothermia
- H = monitor coagulation
- F = risk of renal failure = avoid NSAIDs
- G = adequate nutrition
  - Prevent constipation = minimise flares of hepatic encephalopathy
- F = careful fluid balance
- I = monitor for infection

Common questions / related topics13 / 14

Anaesthetic considerations of CLD
Child-Pugh classification of severity of liver disease
liver transplantation
- indications
- contraindications
hepatosplenomegaly
- differential
acute hepatitis
- cases
needlestick injury for hepatitis viruses
anaesthetic complications of chronic alcoholism

Anaesthesia for CLD pre-transplant

Severe CLD

Links / References14 / 14

Lung disease in Liver disease

https://www.uptodate.com.acs.hcn.com.au/contents/anesthesia-for-the-patient-with-liver-disease

https://www.mdcalc.com/calc/78/meld-score-model-end-stage-liver-disease-12-older

AGA Clinical Practice Update on Surgical Risk Assessment and Perioperative Management in Cirrhosis: Expert Review, 2019

[Summary of Literature on Surgical Risk in Cirrhosis, Gastroenterological Society of Australia, 2014]