Liver Flashcards
What is the function of Kupffer cells?
Removes bacteria before the blood drains into the vena cava
Where is bile produced?
Hepatocytes in the liver
What is the pathway of bile?
-Produced
-The canaliculi drains bile into the bile duct
-Bile ducts converge to make the common bile duct
-Cystic duct and the pancreatic duct join the common hepatic duct
-Sphincter of Oddi controls the flow of bile
-Contraction of the sphincter increases biliary pressure
How much CO and blood flow does the liver receive ?
30%
1500mL
Which two vessels supplies the liver?
Portal Ven
Hepatic artery
Breakdown of the two vessels that supplies the liver?
Portal Vein - 75% of Blood and 50% of O2
Hepatic artery - 25% of blood and 50% of O2
What determines portal blood flow?
Splanchnic circulation
What is the normal pressure of the portal vein? Sinusoids?
Portal 7-10
Sinusoids - 0
What is the diagnostic pressure for portal HTN of the portal vein? Sinusoids?
Portal >20
Sinusoids > 5
What is the hepatic arterial buffer response? What mediates this response? What blocks this?
If there is a reduction in portal vein flow, it is compensated by increased hepatic artery flow
Mediated through Adenosine
Blocked by severe liver disease
How does GA and neuraxial anesthesia affect hepatic blood flow?
Decreases it because of a decreased MAP
What coagulation factors are not produced by hepatocytes?
3 - Tissue factor
4- Calcium
vWF - (vasculature)
Still made in the liver but not hepatocytes
8 - antihemophilic factor (liver sinusoidal cells)
Which coagulation factors are dependent on vit K? Which anticoagulants are dependent on endothelial cells?
Factors - 2, 7, 9, 10
Anticoagulants - Protein C, Z, S
Which plasma proteins are produced by the liver?
Albumin - oncotic pressure and acts as a reservoir for acidic drugs
Alpha 1 - Reservoir for basic drugs
Pseudocholinesterase - metabolizes succ and ester locals
Gluconeogenesis, etc
What role does the liver play in amino acid deamination? What happens if they liver can’t?
Amino acid deamination allows the body to convert proteins to carbs and fats
this process creates large amount of ammonia. The liver converts ammonia to urea which the kidney eliminates
Failure to clear the ammonia leads to encephalopathy
Where does bili come from? How is it cleared?
Recycling of RBCs after 120 days
Eliminated through stool
Spleen
Bound to albumin
Conjugates with glucuronic acid to increase water solubility
Excreted into bile
What are the best tests of hepatic synthetic function? What is the best for acute injury?
PT - 12 to 14 seconds
Very sensitive because of short half life
Albumin - 4.0
Not sensitive because of long 21 day half life
Best tests for hepatocellular injury?
AST 10-40 units
ALT 10-50 units
Marked elevation of both suggests hepatitis
AST/ALT ratio greater than 2 suggests what?
Cirrhosis or alcoholic liver disease
3 tests for biliary duct obstruction? Most specific?
***5-Nucleotidase (0-11)
Y Glutamyl transpeptidase (0-30)
Alkaline phosphatase (45-115)
Liver photo
Which hepatitis has the highest incidence?
A - 50%
B - 35%
C- 15%
D - coinfection with B
How is each hepatitis transmitted?
A - oral fecal
B - IV or sex
C- IV
D- IV
How is each hepatitis prevented?
A- pooled gamma globulin, Hep A vaccine
B- Hep B immunoglobulin, Hep B vaccine
C- Interferon + Ribavirin
How does Tylenol harm the liver? What is the treatment?
Tylenol creates a toxic metabolite called NAPQI but normally glutathione conjugates this
Tylenol consumes all the glutathione which is required for phase 2 reactions
Treatment is oral N-acetylcysteine within 8 hours of overdose
How do halogenated anesthetics harm the liver?
Des, Iso, Halothane are metabolized to inorganic fluoride ions and TFA
Halothane is the worst
SEVO does not make TFA
Most common causes of chronic hepatitis ?
- Alcohol
- Hep C
Can patients have surgery with hepatitis?
Acute hepatitis - NO
Chronic - yes if stabilized
How can hepatic blood flow be maintained?
Use iso and avoid halothane
Avoid PEEP
Ensure normocapnia
Liberal use of IV fluids
Regional anesthesia as long as now coag issues
**Which drugs should be avoided with liver failure?
Tylenol
Halothane
Amiodarone
Antibiotics: PCN, tetracycline, sulfas
How does alcohol affect MAC?
Chronic - increased
Acute - decreased
Alcohol potentiates GABA so an increased affect with benzos
Alcohol inhibits NMDA
Early signs of alcohol withdrawal ? How soon?
6-8 hours after BAC returns to normal and peak at 24 hours
Early - Tremors, hallucinations, nightmares
Late signs of alcohol withdrawal ? Treatment?
Increased SNS, N/V, agitation, confusion
Treatments - beta blockers, alcohol, alpha 2 agonists
S/sx and treatment for delirium tremens?
S/sx - grand mal seizures, tachycardia, hypo/hypertension, combativeness
Treatment - Diazepam or beta blockers
Why are alcoholics susceptible to Wernicke-Korsakoff syndrome?
They are deficient in B1 (thiamine)
S/sx - loss of neurons in the cerebellum
Etiologies of cirrhosis photo
What is cirrhosis?
Healthy liver tissue is replaced with nodules and fibrotic tissue.
How does cirrhosis affect liver blood flow? Consequence?
Reduces blood flow and increases resistance - portal HTN
Creates collateral vessels
Drugs and toxins remain in the body longer
What is a MELD score?
Measures 3 factors
Bili, INR, and creatinine
Low risk < 10
Intermediate risk 10-15
High risk > 15
What is the child-pugh score?
Measures 5 factors
Albumin, PT, bili, ascites, and encephalopathy
Class A, 5-6 points = 10% risk of mortality
Class B, 7-9 points = 30% risk
Class C, 10-15 points = 80%
Class C must be managed medically before surgery
How does cirrhosis affect SVR, BP, CO?
SVR and BP is decreased
CO is increased
How does cirrhosis affect RAA\S?
Increased which leads to increased blood volume
How does cirrhosis affect peripheral blood flow?
Increased which leads to increased SvO2
How does cirrhosis affect response to vasopressors?
Decreased response
How does cirrhosis affect the heart?
Diastolic dysfunction
How does cirrhosis affect portal HTN? What does portal HTN lead to?
Creates portal HTN
Increased to hepatic vascular resistance which increases back pressure to proximal organs
Creates esophageal varices
Splenomegaly which leads to thrombocytopenia
How does cirrhosis affect Ascites ?
Creates it
Decreased oncotic pressure
Decreased protein binding
Increased Vd
Hypotension
How does cirrhosis affect pulmonary?
Restrictive disease
Respiratory alkalosis
Hepatopulmonary syndrome
Portopulmonary HTN
How does cirrhosis affect encephalopathy?
Decreased hepatic clearance which leads to increased ammonia which causes Cerebral edema and INCREASED ICP
Reduce protein, give lactulose and abx
How does cirrhosis affect kidneys?
Hepatorenal syndrome - Decreased GFR which leads to kidney failure
Renal hypoperfusion - Decreased GFR and Increased RAAS which leads to NA and H2o retention
What is a TIPS procedure? What is the biggest risk?
Bypasses hepatic circulation and shunts blood from the portal vein to the hepatic vein (outflow vessel)
Reduces back pressure and reduces esophageal varices
Bleeding is a high risk
Which hormone stimulates bile release?
Cholecystokinin (CCK) stimulates gallbladder contraction
Released due to ingested food
Choley photo
What is cholecystitis? How is it treated?
Inflammation of the gallbladder
Cholecystectomy
What is cholelithiasis? How is it treated?
Gallstones
Cholecystectomy
What is choledocholithiasis? How is it treated?
Stones in the common bile duct
ERCP
Who is at the highest risk for gallstones?
3 F’s
Fat
Female
40
S/sx of gallstones?
Leukocytosis
Fever
RUQ pain - pain is worse during inspiration (Murphy’s sign)
What is used to relax the sphincter of ODDI?
Glucagon*** - increased risk of PONV
Also
Naloxone
Nitro
Glyco
Atropine
Which 3 organs does the celiac artery provide blood flow to?
Liver
Spleen
Stomach
Which 3 organs does the superior mesenteric artery provide blood flow to?
Pancreas
Small intestine
Colon
Which organ does the inferior mesenteric artery provide blood to?
Colon
Which 4 things increase splanchnic vascular resistance?
SNS stimulation
Pain
Hypoxia
Propranolol
Hepatocytes produce?
Thrombopoietin
Alpha-1
Factor 7
Which plasma proteins are synthesized in the liver?
all of them except immunoglobulins
What is
Glycogenesis?
Glycogenolysis?
Gluconeogenesis?
Glycogenesis - Glucose is stored as glycogen
Glycogenolysis- Glycogen is cleaved into glucose
Gluconeogenesis- Glucose is created from non carbohydrate sources
Normal PT time? What does this measure?
12 - 14 seconds?
Synthetic function
Normal Albumin? What does this measure?
3.5-5 g/dl
Same as potassium
Measures synthetic function
Normal AST and ALT? What do these measure?
AST- 10 - 40
ALT - 10- 50
Hepatocellular injury
Normal Bili? What does this measure?
0-11
Hepatic Clearance
Normal alkaline phosphatase? What does this measure?
45-115 units
Biliary duct obstruction
Normal gamma glutamyl transpeptidase? What does this measure?
0-30 units
Biliary duct obstruction
Normal 5 Nucleosidase? What does this measure?
0- 11
Biliary duct obstruction
Which hepatitis does not cause cirrhosis or cancer?
Hep A
Which three drugs are associated with drug induced hepatitis?
Halothane
Tylenol
Alcohol
What is the typical onset of delirium tremens after a patient stops drinking?
2-4 days
What are some changes seen in patients with cirrhosis of the liver?
- Right to left shunt
-Respiratory alkalosis (breathing off acid)
-Increased CO
-Decreased GFR and SVR
What is the pre anhepatic phase?
Surgical incision to cross clamping
Significant blood loss
Risk for aspiration
Will have hemodynamic instability
Prevent hypothermia
What is the anhepatic phase?
Begins with removal of old liver and ends with implantation of new
Patient will have no liver function
New liver must be in within an hour
*Lower K with hyperventilation, D50, insulin, bicarb, albuterol, CVVHD
What is the neohepatic phase?
Begins with reperfusion of new liver and ends with biliary anastomosis
-**Highest risk for hyperkalemia
-Avoid high CVP
-Watch temp and electrolytes
- Post reperfusion syndrome most important consideration. Hypotension more than 30% below baseline for 1 minute
What TEE views should be avoided with esophageal varices?
All transgastric
What special airway consideration for a liver transplant?
RSI for risk of aspiration
Which two ducts converge at the ampulla of Vater?
Pancreatic duct and the common bile duct
How does propranolol reduce hepatic blood flow?
Constricts the hepatic artery
Which zone of the liver is most prone to hypoxic injury?
Zone 3 - closest to central vein
Most significant risk factors for halothane hepatitis?
Female
Fat
Forty
Are collateral vessels formed in the inside or outside of the liver in cirrhosis?
Outside
