Hepatic Lecture Flashcards
(128 cards)
1
Q
the liver is the largest organ, making up what % of body weight in adults and neonates?
A
2% adults (1.5 kg)
5% neonates
2
Q
the liver has __ segments
A
8
3
Q
the liver has __ lobes
A
2
4
Q
the functional units of the liver are what? (2)
A
1) lobule
2) acinus
5
Q
what % of the total blood volume goes to the liver?
A
10-15%
6
Q
the liver holds ___ ml of blood per 100gm of tissue
A
25-30 ml
7
Q
the liver holds blood that is ___% venous blood
A
70% venous blood
8
Q
hepatic blood flow is _____ ml/min
A
1200-1400 ml/min
9
Q
hepatic blood flow receives ___% cardiac output
A
25%
10
Q
where is there more blood flow; the portal vein or the hepatic artery?
A
portal vein (70-80%) over hepatic artery (20-30%)
11
Q
what is the hepatic acinus?
A
the functional microvascular unit of the liver
12
Q
what does the hepatic acinus consist of? (4)
A
- terminal portal venule
- hepatic arteriole
- bile duct
- lymph vessels and nerves
13
Q
describe hepatic blood flow
A
high flow, low resistance
14
Q
how large of a blood reservoir is the liver?
A
normal 450ml (10% TBV) expandable to 0.5-1 L in cases of CHF
15
Q
the liver contains ____ of all lymph in the body
A
half
16
Q
the hepatic artery is dependent on _______ to perfuse the liver
A
systemic arterial pressure
17
Q
a highly compliant liver has ____ ml/mmHg for each 100g of liver weight
A
2-3 ml/mmHg
18
Q
raising hepatic venous pressure by 1mm/hg results in an increase of ____ ml in a highly compliant liver
A
40-50 ml
19
Q
regulation of hepatic blood flow is done intrinsicly by
A
- autoregulation
- metabolic control
20
Q
regulation of hepatic blood flow is done extrinsically by
A
- neural control
- humoral control
21
Q
how will anesthetics affect hepatic blood flow?
A
decrease
22
Q
how does controlled ventilation affect portal venous blood flow?
A
decrease
23
Q
regional anesthesia will have what affect on hepatic blood flow?
A
decrease, along with decreasing systemic blood pressure
24
Q
how will controlled hypotension by sodium nitropresside alter hepatic blood flow?
A
no change, due to an increased portion of blood flow to the portal vascular bed
25
can the site of surgery affect hepatic blood flow?
yes, upper abdominal surgery decreasing flow up to 60%
26
the liver synthesizes all proteins with the exception of what?
gamma globulin
27
where is albumin produced?
the liver
28
what does albumin do?
maintains intravascular oncotic pressure
29
what is used as a indicator of chronic liver disease?
serum albumin
30
what is a normal serum albumin?
3.5-6 g/dl
31
the liver produces what coagulation factors? (9)
vitamin K dependent factors
- II, VII, IX, and X
non-dependent factors
- V, XI, XII, XIII, fibrinogen
32
what factors are NOT produced byt the liver?
- III (tissue thromboplastin)
- IV (calcium)
- VIII (von willebrands)
33
what is a good indicator of acute hepatic dysfunction?
- PT (prothrombin time)
34
what % liver function is needed to maintain adequate coagulation?
20-30%
35
what is a byproduct of deaminating amino acids by the liver?
ammonia
| * can also be produced by GI bacteria
36
how does the liver remove ammonia?
by forming urea
37
the liver stores large amounts of carbohydrates in the form of what?
glycogen
38
how long until liver glycogen is depleted while NPO
24 hours
39
how does the liver help regulate blood glucose?
- stores glucose as glycogen
| - converts carbohydrates, amino acids and TAGs
40
in PTs with impaired liver function, will glucose go up or down?
up, higher than post-meal levels found in normal hepatic function
41
the majority of cholesterol synthesized in the liver is converted to...
bile salts, then secreted in the bile
42
what phagocytize bacteria entering the liver from the intestines?
kupffer cell (macrophages)
43
how much bacteria does the liver trap using Kupffer cell macrophages before the bacteria can enter systemic circulation?
over 99%
44
red blood cell life span is how long?
120 days
45
heme that is released from the breakdown of hemoglobin is converted into
free bilirubin
46
free, or unconjugated bilirubin, is conjugated in the liver and secreted where?
into the bile to be transported to the small intestines
47
what is jaundice?
the yellow-green tint of the body tissue that results from bilirubin accumulation in extracellular fluids
48
when is skin discoloration of jaundice visibile?
when plasma bilirubin reaches 3x normal value
49
how can bilirubin accumulation occur? (2)
- increased breakdown of hemoglobin (hemolysis)
| - obstruction of bile duct
50
hemolytic jaundice is associated with what?
an increase in unconjugated (indirect) bilirubin
51
obstructive jaundice is associated with what?
an increase in conjugated (direct) bilirubin
52
unconjugated bilirubin (lipid soluble) travels to the liver bound to what?
albumin
53
what does the liver do to bilirubin to make it exreteable?
conjugates bilirubin to a water-soluble form
54
how much bilirubin is produced daily?
300 mg
55
narcotics effect on common bile duct pressure
increases
56
what narcotic has the greatest effect on common bile duct pressure
fentanyl (increases)
57
how is an increase in bile duct pressure via narcotics attenuated? (4)
- NTG
- nalonone
- atropine
- glucagone
58
what is drug biotransformation?
converstion of lipophilic substances to excretable metabolites
59
phase I enzymatic reactions consists of...
oxidation by cytochrom P-450 (>90%)
60
phase II enzymatic reactions consist of...
conjugation with glucoronic acid to increase water solubility for biliary excretion
61
what factors affect drug metabolism? (5)
- HBF
- protein binding
- intrinsic hepatic clearance
- enzyme inducing compounds
- self-induced drugs
62
what liver enzyme tests are used to evaluate impaired liver function? (4)
- alkaline phosphatase (ALP)
- alanine transaminase (ALT)
- aspartate transaminase (AST)
- gamma-glutamyl transpeptidase (GGTP)
63
what is the alkaline phosphatase (ALP) test for?
- evaluates liver function
| - enzyme levels increased when bile ducts are blocked
64
what is the alanine transaminase (ALT) test for?
- a liver function test
| - best for detecting hepatitis
65
what is the aspartate transaminase (AST) test for?
evalutates liver function,
| not as specific as ALT or ALP
66
what is the gamma-glutamyl transpeptidase (GGTP) test?
sensitive marker for cholestatic damage
67
normal alanine aminotransferase (ALT) levels
5-40 IU/L
68
normal alkaline phosphatase (ALP) levels
13-39 IU/L
69
what (all) tests can be used to evaluate liver function? (7)
- liver enzymes (ALT, ALP, AST, GGT)
- PT
- total proteins
- albumin
- bilirubin
- platelets
- ammonia
70
how is serum albumin effected by liver disease (like cirrhosis)?
decreased
71
what clotting factor is associated with acute liver disease?
factor VII
72
prothrombin is which factor?
factor II
73
whats a normal PT?
10-12 seconds
74
PT can be affected by (5)
- liver disease
- coumarin therapy
- heparin therapy
- vit. K def
- factor VII
75
what is the normal albumin range?
3.9-5.0 g/dl
76
conjugated bilirubin is...
water soluble for excretion
77
unconjugated bilirubin is...
pre-hepatic, not yet processed by liver
78
increased total bilirubin causes...
jaundice, leading to
- hemolytic anemia
- def. bilirubin metabolism
- bile duct obstruction
79
if direct bilirubin is elevated, what is going on?
- liver is conjugating bilirubin normally
- liver cannot secrete bilirubin
- bile duct obstruction by cancer or gallstones
80
if direct bilirubin is normal in a PT with jaundice, what is going on?
- excess of unconjugated bilirubin
| - hemolysis, hepatitis, or cirrhosis should be expected
81
normal total bilirubin range
0.2-1.5 mg/dl
82
normal direct (conjugated) bilirubin range
0.0-0.03 mg/dl
83
normal indirect (unconjugated) bilirubin range
0.2-0.8 mg/dl
84
What are some possible liver diseases?
- hep A, B, C, D, E
- cirrhosis
- cholelitiasis, cholecystitis
- hepatic tumors
85
Hep A manifests as...
acute viral hepatitis;
- fever, jaundice, painfully enlarged liver
- not common in developed contries
86
Hep B and C are transmitted by...
- blood transfusion
- needle sticks
- sexual contact
- across placenta
87
Hep B manifests as...
acute w/ development to fulminant hepatitis and rapid liver destruction
88
is there an available Hep B vaccine?
yes
89
what % of hep B will develop chronic hepatitis?
10%
90
what % of hep C will develop chronic hepatitis?
50%
91
hep C increases risk of developing what?
- cirrhosis (20%)
| - hepatocellular carcinoma
92
hep D is a co-infection acquired with...
Hep-B
93
what is hep D?
an acute infection that can develop into fulminant hepatitis or cirrhosis
94
what is hep E?
hepatitis related to poor hygiene or contaminated water
95
which Hepatitis is the greatest risk for anesthesia?
Hep B
96
how do you asses Hep B?
coagulation pre-op
97
how do you treat hep B?
- FFP
- monitor glucose
- maintain normal hepatic flow
- avoid hypercarbia
98
how can drug metabolism be affected by severe hepatitis?
prolonged effect
99
how are benzos affected by hepatic disease?
prolonged and more intense effect.
| - avoid benzos
100
how are opioids affected by hepatic disease?
prolonged effect of morphine and alfentanil
| - fentanyl and sufentanil not affected
101
how are non-depolarizing muscle relaxants affected by hepatic disease?
prolonged effect
102
what are good choices for muscle relaxant in PTs with hepatic dysfunction? Why?
cisatricurium or atracurium
| - broken down by plasma esterases
103
what is cirrhosis?
liver disease with distortion of normal hepatic structure caused by cell destruction
- leads to liver failure
104
who gets cirrhosis?
- chronic hepatitis
| - alcoholics
105
what is cholelitiasis?
the formation of calculus (stones) in the gallbladder via cholesteral crystal precipitation
106
what is cholecystitis?
inflammation of the gallbladder
107
what should you consider with PTs coming in for a cholecystectomy?
RSI, may present with recent N/V
108
why no opioids if the surgeon will be performing a cholangiogram?
may cause sphincter of oddi constriction, preventing contrast dye from flowing out of common bile duct
109
what will a PT with jaundice look like?
yellowing of the skin and eyes from bilirubin accumulation
110
how much bilirubin in PRBC?
250 mg
111
elevation in unconjugated bilirubin can lead to a condition resulting in seizures and brain damage, called what?
kernicterus
112
what % of hepatic tumors are hepatocellular?
80-90%
113
what % of hepatic tumors have underlying cirrhosis of usually alcoholic origin?
75%
114
what are six considerations for hepatic resection?
```
1 - large bore IV
2 - a-line
3 - central line for CVP
4 - epidural catheter for post-op pain
5 - keep PT hypovolemic during resection
6 - T&C 6 units of blood
```
115
what is normal portal vein pressure?
6-12 cmH2O
| 8-16 mmHg
116
what is the major clinical manifestation of portal hypertension?
GI bleeding
| *bleeding in esophagus means severe
117
how do you treat portal hypertension?
- stopping the hemorrhage
- decompressing portal venous circulation
- large volume blood transfusion
118
What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS) used for?
to decrompress portal circulation in the case of portal hypertension
- buys time waiting for liver transplant
119
what are ascites?
ascites is the accumulation of serous fluid in the peritoneal cavity. It compresses abdominal viscera
120
What should you watch for following a decompression of fluid caused by ascites?
- hypovolemia
| - hypotension
121
PTs with ascites often present with what?
arterial hypoxmia
| - PaO2 (60-70 mmHg)
122
how do you treat ascites?
induce diuresis with aldactone antagonist (spironolactone)
| *1 liter per day max diuresis
123
how can you minimize hypotension caused by managing ascites?
IV colloids
124
whats the best treatment of coagulopathy?
FFP
125
other than FFP, what can one used to normalized a patients PT?
platelets and cryo
126
what is hepatic encephalopathy?
hepatic coma
| confusion, flapping hands, fruity breath, 88% risk mortality
127
what causes encephalopathy? (3)
- cerebral intoxication (liver not metabolizing GI contents)
- protein byproducts from bacteria
- ammonia (NH3) not converted to Urea by liver
128
how do you treat encephalopathy?
- protein restriction
- antibiotics (neomycin)
- reduce diuretic therapy
- treat hypokalemia
- restrict sedatives
