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51 Cards in this Set
- Front
- Back
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How does the liver affect glucose homeostasis?
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formation, storage, and release of glucose by gluconeogenesis and glycogenolysis
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What is the half life of albumin and how does this affect acute liver dysfunction?
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23 days
-acute dysfunction will generally not decrease serum albumin levels |
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With what levels of decreased albumin do you see increased drug sensitivty for drugs that bind to albumin?
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<2.5g/dL
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What is the cause of clotting deficiency with liver dysfunction?
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decreased factor production and vit K deficiency from lack of bile production
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Why do patients with liver dysfunction get thrombocytopenia?
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hepatosplenomegaly
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When do you see decreased cholinesterase activity in liver disease?
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prolonged and severe liver disease
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What hypotensive medication is contraindicated in severe liver disease?
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SNP
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What happens with impairment of bile production?
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steatorrhea and vit K deficiency
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What determines hepatic blood flow?
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HBF = perfusion pressure - splanchnic vascular resistance
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How do surgical incisions affect hepatic blood flow?
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surgical incisions decrease hepatic blood flow,
-the closer the surgical site to the liver, the greater the reduction in hepatic blood flow |
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Albumin less than what level leads to ascites? Why?
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<3.5 bc free water goes from an area of lower to higher oncotic pressure
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What is more specific for the diagnosis of liver disease ALT or prothrombin time?
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ALT
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What hepatitis virus is most commonly transmitted in blood transfusions?
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hepatitis B
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What are the pathologic changes to the liver with cirrhosis?
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liver parenchymal destruction with replacement by collagen
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what are physiologic changes associated with cirrhosis?
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1. hyperdynamic circulation leading to cardiomyopathy and CHF,
2. hypoxemia secondary to right to left intrapulmonary shunt, 3. hypoglycemia, 4. anemia secondary to GI bleeding an lack of folate due to malnutrition, 5. renal failure, 6. hepatic encephalopathy, 7. portal htn, 8. ascites |
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Why is acute alcoholic hepatitis a contraindication to elective surgery?
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carries a 50% mortality rate
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Should you do surgery in patients with cirrhosis?
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not elective surgery
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What is the only nondepolarizer that undergoes significant liver metabolism?
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vecuronium
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Why should you be cautious of narcotics in patients with biliary dysfxn?
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choledochoduodenal sphincter spasm (incidence is very low)
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A patient with cirrhosis that is on sodium restriction preop, how should you manage their fluid intraop?
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preservation of intravascular volume and urine output take precedence intraop
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What are the major functions of the liver?
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1. glucose homeostasis
2. fat metabolism 3. protein synthesis 4. coagulation 5. cholinesterase activity 6. biotransformation of drugs 7. bilirubin excretion 8. bile excretion |
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What are the causes of hypoglycemia in liver failure pts?
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1. insufficient insulin degradation by the liver
2. impaired glucose formation 3. glycogen depletion |
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What is the only protein not produced in the liver?
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gamma globulin
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What is the major protein produced in the liver? What is normal level?
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albumin (normal 3.5-5.5)
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If albumin levels are decreased, what drugs will exist in plasma in less protein bound form and therefore are more pharmacologically active?
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1. barbs
2. midazolam 3. Coumadin |
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What drugs are highly cleared by the liver on first pass metabolism?
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Mnemonic: "Bc Very Largely Metabolized, Dose Adjustment Down Is Needed"
B = beta blockers (propranolol, metoprolol labetolol) V = verapamil L = lidocaine M = morphine, meperidine, midazolam D = diltiazem A = alfentanil, aminophylline D = digoxin I = imipramine N = naloxone, nitroglycerin -effects of these drugs are prolonged in liver failure |
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All clotting factors except for which one is produced in the liver?
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All except for factor VIII
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Which factors have a short t1/2 and you will therefore see clotting abnormalities with acute and chronic liver failure?
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prothrombin (II)
fibrinogen (I) |
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What is the plasma t1/2 of pseudocholinesterase?
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14 days
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Explain process of bilirubin formation and excretion.
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1. old RBCs are degraded by the spleen
2. globin is degraded into amino acids and the heme portion is degraded first into biliverdin and then into bilirubin 3. bilirubin is complexed to serum albumin and transported to the liver 4. liver cells conjugate the bilirubin with glucuronic acid, making it more soluble 5. bilirubin glucuronide can then be secreted into bile - unconjugated bilirubin is the indirect fraction - increases result from liver parenchymal dz - conjugated bilirubin is the direct fraction - increases in bilirubin obstruction |
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What is the first pass effect?
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A phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced befre it reaches the systemic circulation.
-first pass is the fraction of lost drug during the process of absroption which is generally related to the gut wall and liver |
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Where are the 4 enzymes systems that effect first pass of a drug located?
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1. gastrointestinal lumen
2. gut wall 3. certain bacteria 4. liver |
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What routes of admin avoid first pass metabolism?
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1. suppository
2. IV 3. IM 4. inhalational 5. sublingual -these are absorbed directly into the systemic circulation |
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How is the blood supply of the liver unique?
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It receives a dual blood supply
-portal vein 70%, hepatic artery 30% blood supply -hepatic artery 55% of oxygen delivery |
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What is the effect of volatile anesthetics on hepatic blood flow?
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All volatile anesthetics decrease HBF by decreasing hepatic perfusion pressure and increasing hepatic vascular resistance
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What is normal serum biliirubin?
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0.3-1.1
-unconjugated bilirubin 0.2-0.7 - can't be excreted by the kidneys -direct bilirubin 0.1-0.4 - can be excreted |
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At what level of bilirubin does jaundice occur?
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when bilirubin exceeds 3 mg
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If transaminases are ____ there is a high likelihood of acute hepatocellular damage.
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>3x normal
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Where can LDH be found?
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1. liver
2. heart 3. skeletal muscles 4. erythrocytes |
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Which form of LDH is rather specific to the liver?
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isoenzyme-5 fraction
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what helps differentiate between biliary obstruction vs hepatocellular damage?
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Alk phos
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Hepatitis C infection results from what type virus?
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a single stranded RNA virus
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How can the diagnosis of HCV be confirmed?
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by the use of assay of HCV RNA and in some cases a supplemental recombinant immunoblot assay (RIBA) for anti HCV
-most RIBA + pts are potentially infectious as confirmed by PCR tests to detect HCV-RNA -if a pt has anti HCV in serum confirmed by RIBA, without HCV RNA in serum, this suggests recovery from HCV in the past |
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Describe the progression of Hepatitis C virus.
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-spans over several decades
-development of cirrhosis after about 30 years |
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What factors lead to progression of Hep C?
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1. age older than 40 at the time of initial infection
2. daily alcohol intake >50 grams 3. male gender |
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What is a treatment option for Hep C?
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Interferon normalized ALT and reduces inflammation
-thought to decrease viral replication and is better used with other antiviral drugs -relapse is common after it is stopped |
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What inhalational agent is preferred in liver failure?
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Isoflurane bc of its low liver metabolism
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What is the nondepolorizing agent of choice in liver failure?
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atracurium due to its spontaneous degradation at normal pH and temp (Hoffman elimination)
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Which is the volatile agent that produces fluoride in quantities associated with renal dysfunction?
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Methoxyflurane
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Is citrate toxicity more or less common in liver failure pts?
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more common due to its impaired metabolism
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How much bile does the liver make per day?
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about 1 liter
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