Test 4 GI Flashcards
what is defined as the portal triad?
hepatic arteriole
portal venule
bile ductal
microcirculation of the liver lobule is divided into ________ zones that receive varying oxygen content`
3
zone 1 of liver lobule receives __________ blood from the __________ & ________
oxygen rich; adjacent portal vein and hepatic artery
blood entering zone 3 of the liver lobule is _______________
oxygen poor
what zone of the liver lobule is most affected by hypoxia and reactive metabolic intermediates?
zone 3
liver synthesizes all clotting factors except ?
III, IV, and VIII
Vitamin K dependent clotting factors are dependent on what function of the liver?
bile excretion
blood coagulation fx of the liver
- synthesis of clotting factors (except III, IV, VIII)
- synthesis of pro and anti-clotting factors
- produces thrombopoietin
liver receives __________% of CO via dual supply
25%
how much bile is produced daily?
500ml
the hepatic portal vein supplies 75% of the liver inflow, this is due to the ____________________ in the portal vein
low vascular resistance
metabolism functions of the liver
- stores/releases glycogen/site of gluconeogenesis
- urea production (aa and protein metabolism)
- fatty acid, cholesterol, and plasma protein synthesis (lipid metabolism)
T/F: endocrine abnormalities may be more common with liver disease
true
endocrine management fx of liver
- synthesizes and secretes: angiotensinogen, thrombopoietin, thyroid binding globulin
- converts T4 to T3
- inactivates corticosteroids, mineralcorticosteroids, and androgens
in liver dysfunction there may be alterations that affect pharmacokinetics/dynamics of many anesthetic agents. This is because of what function of the kidney
protein synthesis
what protein synthesized in the liver binds amide type local anesthetics, opoids, and propranolol
alpha-1 acid glycoprotein
what protein synthesized in the liver metabolizes succinylcholine and ester local
pseudocholinesterase
drug metabolism is primarily performed by what organ?
liver (hepatic)
what is the goal of hepatic biotransformation within the liver
to make drugs inactive, water soluble, and ready to excrete
phase 1 of hepatic biotransformation
oxidation, reduction, dealkylation, hydrolysis
which phase of hepatic biotransformation is more susceptible to inhibition by advanced age and/or hepatic dysfunction?
phase 1
phase 2 reaction of hepatic biotransformation
conjugation
what is the first pass effect?
pre-systemic elimination of drugs delivered via the oral route
what is the effect on high extraction rate drugs taken orally (lidocaine, propranolol, morphine) due to the first pass effect?
they will have reduced bioavailability due to the presystemic metabolism
what is the effect on drugs with a low extraction rate (tegretol, valium, dilantin, procanamide, warfarin) if taken orally, due to the first pass effect?
will have minor first pass effects, but will have a slow metabolism and are more dependent on hepatic clearance
if liver dysfucnction is known or suspected, what does this mean for your anesthetic agent plans perioperatively?
- unknown effects with kinetics and dynamics
- need to weigh risk/benefit of comorbid conditions
- CAREFUL TITRATION
T/F: in the absence of a positive H&P or known liver disease preoperative lab testing is unnecessary
true
what should you evaluate if a pt has a known hx or positive hx of liver dz prior to surgery?
- eval hepatocyte injury/necrosis through ALT, AST, GST (liver fx tests)
- eval hepatic conjugation and excretion (bilirubin)
- eval hepatic excretion (alkaline phosphatase, GGT)
- evaluate protein synthesis (Albumin, PT, INR)
normal AST
10-40 IU/L
normal ALT
10-60 IU/L
what could a ALT of 180/AST of 120 indicate? (i.e. mildly elevated transaminases)
fatty liver
non-etoh steatohepatitis
drug toxicity
chronic viral hepatitis
mildly elevated ALT/AST (3x) normal would be ALT ____; AST ____
180; 120
what is defined as a large increase in ALT & AST
4 - 22x normal (AST: 40-160 - 220-880)(ALT: 40-220 - 240-1320)
an AST/ALT ratio of > 2 indicates
alcoholic liver disease
an AST/ALT ratio of <1 indicates
viral hepatisis
what do liver fx tests (AST/ALT) assess
hepatocyte cellular injury
having ALT of 500 and AST of 700 would indicate?
- acute hepatitis
- chronic hepatitis exacerbation (etoh induced)
- drug/toxin induced hepatocellular necrosis
- severe hepatitis
- ischemia hepatitis complicating circulatory shock
bilirubin orginiates from _______________
breakdown of hemoglobin
unconjugated bilirubin is the _________ soluble form; while conjugated is the ___________ soluble form
lipid; water
normal value for unconjugated bilirubin
1-4 mg/dL
elevated unconjugated bilirubin indicates?
disorder of bilirubin metabolism d/t either excess production of bilirubin through hemolysis or decrease in the uptake and conjugation of bilirubin by hepatocytes
what does elevated conjugated bilirubin indicate?
- impaired intrahepatic excretion or extrahepatic obstruction
- could be d/t gall stones
Bilirubin > 35 indicates
severe liver dz in association with hemolysis or renal failure
T/F: serum albumin is a great indicator of acute liver disease
false; due to 3-week half life it is not a reliable indicator of acute liver dz
other than in liver dz when may albumin levels be low?
enteropathy
burns
nephrotic syndrome
albumin levels can be a significant indicator of what in regards to liver dz?
worsening fx of liver in chronic liver dz
what labs are sensitive indicators of hepatic dz because of short half life?
PT and INR
when might PT be prolonged in the absence of liver dz?
biliary obstruction
congenital coagulation factor deficiencies
DIC
warfarin therapy
what are the 3 types of alcoholic liver dz?
steatosis
hepatitis
cirrhosis
which type of etoh liver dz is usually benign and will resolve with abstinence
steatosis
