Hepatic Surgery Flashcards
(106 cards)
1
Q
where does the liver sit in dogs and cats?
A
cranial abdomen
2
Q
where does the liver sit in relation to the midline?
A
2/3 of liver mass to the RHS of the midline
3
Q
how many lobes is the liver of dogs and cats divided into?
A
4
4
Q
what are the 4 liver lobes found in dogs and cats?
A
left
right
caudate
quadrate
5
Q
what are the lobes of the liver further divided into?
A
sub-lobes and processes
6
Q
what is the largest liver lobe in dogs and cats?
A
left
7
Q
what structures within the abdomen is the liver attached to?
A
diaphragm
right kidney
lesser curvature of the stomach
proximal duodenum
8
Q
what vessel runs through the liver and is strongly attached to it?
A
vena cava
9
Q
how many sources does the liver receive blood from?
A
2
10
Q
what are the 2 sources of blood supply to the liver?
A
hepatic portal vein
hepatic artery
11
Q
where does blood in the hepatic portal vein come from>
A
digestive tract
spleen
12
Q
what is the role of the hepatic portal vein?
A
provides blood rich in nutrients and metabolites to be broken down in the liver
13
Q
what percentage of hepatic blood flow is made up by the portal vein?
A
70-80%
14
Q
what is the role of the hepatic artery?
A
provides oxygenated blood to the liver
15
Q
what percentage of hepatic blood flow is made up by the hepatic artery?
A
20%
16
Q
what percentage of oxygen supply is provided by the hepatic portal vein?
A
50%
17
Q
what percentage of oxygen supply is provided by the hepatic artery?
A
50%
18
Q
what does blood leave the liver through?
A
short hepatic veins
19
Q
what do hepatic veins feed into?
A
vena cava
20
Q
where does portal and arterial blood mix in the liver?
A
sinusoids
21
Q
whereabouts on the liver does blood exit via hepatic veins into the vena cava?
A
dorsal boarder of liver
22
Q
what is one of the main challenges of hepatic surgery?
A
haemorrhage
23
Q
why is haemorrhage such a risk with hepatic surgery?
A
liver is a highly vascular organ
24
Q
why is it essential to understand the liver’s blood supply?
A
to understand portosystemic shunts
25
what aspects of a patients care may liver impairment affect?
surgery
analgesia
anaesthesia
nursing care
26
when will you begin to see signs of liver damage?
once 70-80% of hepatic tissue is lost
27
why are signs of liver damage only seen once 70-80% of hepatic tissue is lost?
liver has high functional reserve
28
what are the main functions of the liver?
Synthesis and clearance of proteins (Albumin)
Metabolism of nutrients (carbohydrates, lipids, amino acids)
Production / activation of clotting factors
Clearance of toxins (ammonia, drugs, etc)
Immunoregulation (Kupffer cells)
Gastrointestinal function
Storage
29
what is stored within the liver?
vitamins
fats
glycogen
copper
30
what is the potential impact of reduced liver function on synthesis and clearance of proteins (Albumin)?
affect on albumin bound drugs and anaesthetic agents
ascites
IVFT less effective due to reduction in oncotic pressure
31
what is the potential impact of reduced liver function on metabolism of nutrients (carbohydrates, lipids, amino acids)?
hypoglycaemia
lethargy
weight loss
32
what nutrients are metabolised by the liver?
carbohydrates
lipids
amino acids
33
what is the potential impact of reduced liver function on production / activation of clotting factors?
clotting problems
haemorrhage
34
what is the potential impact of reduced liver function on clearance of toxins (ammonia, drugs, etc)?
excessive sensitivity to drugs
neurological signs
PUPD
anorexia
vomiting
35
what is the potential impact of reduced liver function on immunoregulation?
endotoxaemia
sepsis
36
what is the potential impact of reduced liver function on GI function?
weight loss
diarrhoea
37
where are bile acids synthesised?
in the liver
38
how are bile acids excreted from the liver?
excreted into hepatic ducts which drain out of the liver and converge to for the common bile duct
39
what forms the common bile duct?
hepatic ducts which drain out of the liver and converge to for the common bile duct
40
what happens to bile when the body is not undergoing digestion?
bile drains from the liver and passes via the cystic duct to the gall bladder where it is stored
41
where is bile stored?
gall bladder
42
how does bile reach the gall bladder?
passes via the cystic duct from the hepatic ducts
43
what is the purpose of the gall bladder?
storage and concentration of bile
44
how does bile leave the gall bladder when digestion is taking place?
flows from the gall bladder via they cystic duct to the common bile duct
45
where does bile drain to from the common bile duct?
duodenum
46
how does bile reach the duodenum?
drains from the gall bladder through the cystic duct and the common bile duct
47
what are the main functions of bile acids?
digestion and absorption of fat
neutralisation of gastric acid and inhibition of gastric acid secretion to prevent intestinal ulceration
48
what is the purpose of neutralisation of gastric acid and inhibition of gastric acid secretion by bile?
prevents intestinal ulceration
49
what tests are involved in the diagnosis of hepatic disease?
Blood tests
Urinalysis
Diagnostic abdominal imaging
50
what blood tests may be run to diagnose hepatic disease?
haematology
biochemistry
blood gas / electrolyte analysis
dynamic bile acid testing (bile acid stim)
51
what diagnostic imaging techniques may be used to diagnose hepatic disease?
radiography
ultrasonography
CT
MRI
scintigraphy
52
what is the best diagnostic imaging modality for diagnosing hepatic disease?
ultrasonography - provides much
more useful information than radiographs
53
what are the main areas of medical management used to stabilise hepatic patients?
prescription diet
oral antibiotics
oral lactulose
54
what is the main nutrition consideration for patients with hepatic dysfunction?
reduced levels of high biological value protein
good protein bioavailability
restricted fat
55
why may a patient with hepatic disease be given oral antibiotics?
to compensate for the livers reduced immunoregulatory action in detoxifying pathogens from the intestines
prevention of endotoxaemia
56
why may a patient with hepatic disease be given oral lactulose?
bind ammonia for excretion in faeces
reduction of risk of hepatic encephalopathy
57
what are the main areas of preoperative care for hepatic patients?
assessment of clotting times
IV antibiotics
IVFT
blood typing if surgery involves risk of significant haemorrhage
general patient care
58
what should be checked when evaluating patient clotting times?
APTT
platelets
PT
59
what is APTT?
activated partial thromboplastin time
60
what is PT?
prothrombin time
61
why are clotting tests essential in hepatic patients?
clotting is abnormal in ~50% of dogs with liver disease
exacerbates risk of haemorrhage
62
what should be done if coagulation tests are abnormal?
pre treatment with vitamin K or FFP
63
why are IV antibiotics indicated in hepatic patients?
due to the presence of bacteria in the liver and risk of endotoxaemia / sepsis
64
what would be an appropriate antibiotic for use in a preop hepatic patient?
broad spectrum antibiotic such as potentiated amoxycilin, whilst awaiting the results of culture and sensitivity testing
65
what drugs should be avoided in hepatic patients?
those that undergo hepatic metabolism
66
what is involved in IVFT provision for hepatic patients?
IVFT needed for replacement of losses via V/D
IVFT less effective due to reduced albumin and so reduced oncotic pressure
correction of electrolyte imbalances
67
what may require supplementation in hepatic patients?
glucose
68
why may glucose supplementation be necessary in hepatic patients?
may already be hypoglycaemic
can be caused by significant liver resection
69
what amount of liver resection may cause hypoglycaemia?
70%
70
what is needed to manage / assess patient hypoglycaemia?
regular blood serum monitoring
71
when should pr-op blood typing be performed in hepatic patients?
if surgery involves significant risk of haemorrhage (e.g. liver lobectomy)
72
what aspects of general patient care may be needed for hepatic patients?
more regular access to water and U opportunities due to PUPD
TTE due to anorexia
73
what should be done if a surgery carries high risk of haemorrhage?
blood type
cross match if previous transfusion
blood products available
74
what are the main hepatic and biliary surgical procedures?
liver biopsy
partial / complete liver lobectomy
surgical correction of PSS
cholecystectomy
cholecystoenterostomy
75
what are the main methods for liver biopsy?
US guided percutaneous (FNA or Tru-cut)
open surgical
laporoscopic
76
what is the benefit of percutaneous sample techniques?
less risk than surgical
77
what are the disadvantages of percutaneous sample techniques?
diagnostic accuracy is poor
78
what are the advantages of surgical liver biopsy techniques?
more accurate
yield better sample
allow gross visualisation and examination of abdominal organs
79
what is liver biopsy indicated for?
To establish diagnosis / prognosis where hepatic disease is suspected
80
what is hepatic lobectomy indicated for?
removal of masses, abscess, or in liver lobe
torsion
81
what are the risks associated with hepatic lobectomy?
haemorrhage
liver failure
portal hypertension
82
what are cholecystectomy and cholecystoenterostomy indicated for?
biliary tract rupture
bile peritonitis
diseases causing Extrahepatic Biliary Obstruction
83
what diseases may cause Extrahepatic Biliary Obstruction?
gall bladder mucocele
choleliths,
Pancreatitis
Neoplasia
84
what is cholecystectomy?
removal of the gall bladder
85
what is cholecystoenterostomy?
rerouting gall bladder to the duodenum
86
what is the most crucial part of the biliary system that should be preserved wherever possible?
common bile duct
87
what are the key perioperative considerations for hepatic surgery?
hypotension
hypothermia
haemorrhage
coagulation abnormalities
IVFT
premedication and induction agents
ventilation may be needed
antibiotics
88
what blood pressure monitoring is needed in hepatic surgery patients?
essential ideally via arterial line
89
what can be done to manage hypothermia in hepatic surgery patients?
close monitoring
utilise heating devices
90
what can be done to manage haemorrhage in hepatic surgery patients?
coagulation abnormalities screened for and appropriate treatment taken
Appropriate methods of haemostasis should be available
replacement blood products may be needed
91
what is the key factor in premediation and induction drug choice in hepatic patients?
avoid drugs that undergo hepatic metabolism
92
what are the main post operative care considerations for hepatic surgery patients?
ICU needed
analgesia
monitoring
minimum database
antibiotics
nutrition
sepsis/SIRS
93
how long will a patient be hospitalised for following most hepatic surgeries?
24 hours at least
longer for biliary and PSS surgery
94
what should be monitored in the post op period for hepatic patients?
physical parameters
BP
blood gas/electrolytes
signs of haemorrhage
leakage of bile
hypothermia
hypoglycaemia
sepsis or SIRS
95
what are the 2 main types of portosystemic shunt (PSS)?
congenital
aquired
96
what percentage of PSS are congenital?
80%
97
what is a portosystemic shunt?
anomalous blood vessel which connects the hepatic portal vein with the systemic circulation (e.g. caudal vena cava) thereby bypassing the liver and diverting some of the portal blood supply away from the liver
98
what percentage of PSS develop later in life (acquired)?
20%
99
why do aquired portosystemic shunts develop?
secondary to other disease like chronic portal hypertension
100
what are the two types of congential shunt?
extrahepatic
intrahepatic
101
what dog breeds to do extraheptic shunts occur more commonly in?
small breed dogs (e.g. yorkie or westie)
102
what dog breeds to do intraheptic shunts occur more commonly in?
large breed dogs (e.g. labradors)
103
what type of congenital PSS is more common?
extrahepatic
104
what is involved in bile acid stimulation tests?
patient is starved for 12 hours and a sample taken
they are then fed and a further sample taken 2 hours later
105
what tube is needed for bile acid stim?
serum
106
list anaesthetic considerations for a PSS patient
drug choice - non hepatic metabolism
duration of drug action
dose carefully
care with IVFT - reduced oncotic pressure
Hypoglycaemia - starvation of no more than 8 hours
hypothermia and glucose consumption through shivering
clotting times and haemorrhage risk
art line
