Liver Flashcards
Kidney is to nephron as liver is to
Lobule (acinus)
How much lymph is made in the liver and where is it made?
About 50% of the body’s lymph is made there by hepatocytes, and drain into the space of Disse before emptying into the lymphatic duct
Hemoglobin to Bilirubin metabolism
- Old RBCs are cleared by the spleen - In the spleen = Hgb -> Heme -> Bilirubin (Unconjugated) - Unconjugated bilirubin is lipophilic and neurotoxic. Travels bound to albumin to liver. - Liver conjugates it with glucuronic acid to increase it’s water solubility - This is now CONJUGATED bilirubin and is excreted in the bile
PT and liver function
Good for detecting ACUTE liver injury. This is because factors V and VII have short 1/2 lives (
Albumin and liver function
Not very specific for liver disease because many things can cause albumin levels to decrease - Not good indicator of acute liver disease (1/2 life of albumin is 21 days)
AST/ALT ratio > ___ suggests cirrhosis or alcoholic liver disease
2
This is the MOST sensitive lab indicator of biliary tract obstruction
5-NT 5-NT > GGTP > AP
In hepatocellular injury, will you see a rise in conjugated or unconjugated bilirubin
Conjugated
This clotting factor is made by the liver but NOT by hepatocytes
Factor VIII It’s made by sinusoidal cells
How liver handles Tylenol
- Tylenol produces a toxic metabolite called NAPQI - This is normally conjugated with glutathione so be excreted in the bile - In this case, all the glutathione gets used up and NAPQI starts harming the liver
Risk factors for halothane hepatitis
Fat females > 40 with multiple exposures. - Genetics - CYP2E1 induction (from alcohol, ionized, and phenobarbital)
How does alcohol affect the liver
Impairs fatty acid metabolism, head to fat buildup within the liver –> hepatomegaly
Why is propranolol good in liver failure?
It’s a NONSELECTIVE BB - B1 = decreased CO - B2 = splanchnic vasoconstrition Remember that splanchnic vasoconstriction will reduce portal venous pressures and treat esophageal varies
Propanalol - how does it reduce the blood flow to the liver
through constriction of the hepatic artery - it’s a non selective BB
How does amiodarone affect the liver?
It’s hepatotoxic
Main 2 considerations for patients with liver injury presenting for surgery
1) Maintain hepatic BF 2) Avoid any drugs that are hepatotoxic or suppress the CYP450
Anesthesia considerations for pt with acute hepatitis
1) Maintain hepatic BF - Use Iso (preserves BF the best) - Avoid PEEP (increases resistance to hepatic drainage, and remember that increased hepatic venous pressure will decrease hepatic perfusion pressure) - Ensure normocapnia - Lots of IV fluids - Regional OK as long as no coag defects 2) Avoid hepatotoxic drugs or those that suppress the CYP450 - Tylenol - Halothane - Amiodarone - Antibiotics (PCN, tetracycline, and sulfonamides)
Effects of alcohol on GABA and NMDA receptors
Agonist at GABA Antagonist at NMDA
Early and late signs of alcohol withdrawl
Early: tremors and distorted perception (hallucinations and nightmares) Late: Increased SNS activity (oh fuck, where’s my alcohol??), N/V, insomnia, confusion, and agitation
Treatment of alcohol w/d
Alcohol, BBs, and A-2 agonists
When do DTs present?
2-4 days without alcohol - Grand mal seizures and combativeness
Treatment of DTs
Diazepam or other benzos BBs
Consequence of portosystemic shunts
These shunts occur as blood tries to bypass the liver in high portal pressures. This blood does not get filtered or processed by the liver, resulting in them remaining in circulation for a longer period of time
MELD score looks at
3 things: - Serum bilirubin - Serum creatinine - INR
What are hepatopulmonary syndrome and portopulmonary HTN?
Hepatopulmonary syndrome - Pulmonary vasodilation leads to increased R–>L shunting and hypoxia Portopulmonary HTN - Portal HTN + Pulmonary HTN - PAP > 25
Why do BB not work on portal vein
What’s the most common cause of viral hepatitis in the US
The incidence of viral hep is:
What volatile gases can cause immune mediated hepatotoxicity?
Volatile gases at 1 MAC - how do they impact hepatic flow ?
Liver failure
are the patients more or less sensitive to vasopressors
Child pugh scores - what does it look at ?
Child Pugh score - what does it mean?
MELD what does it look at?
( Model of End Stage Liver disease )
- INR
- Bilirubin
- serum creatinine
MELD scores - what do they mean ?
Esophageal varices treatment
Alcohol withdrawal syndrome - treatment
What is Disulfiram used for?
For alcohol abstinence (not for acute withdrawals)
used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol
Cardiovascular changes with liver disfunction
Pulmonary changes with liver dsfxn
CNS changes with liver dsfxn
ANS chnages with liver dsfxn
Renal changes with liver dsfxn
Hematologic changes with liver dsfxn
