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What are the liver lobes in dogs and cats, and what is their orientation?
- left lobe (lateral and medial portions)
- quadrate
- right medial
- right lateral
- caudate (papillary and caudate processes)
- in dogs and cats, fissured/ pedunculated (other species bunched without separations)
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Where is the gall bladder located?
between the right medial and quadrate liver lobes
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Describe the dual afferent blood supply to the liver.
- portal vein: drains stomach, spleen, intestines, pancreas- brings nutrients for metabolism
- hepatic artery (from aorta): oxygenated blood
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Describe the venous drainage of the liver.
hepatic veins drain into caudal vena cava--> right atrium
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What are the ligaments (and their attachments) of the liver? (5)
- Coronary ligament: attaches liver to diaphragm
- Falciform ligament: liver from midline, fatty
- Right and left triangular ligaments: attach the lateral lobes to the diaphragm
- Hepatorenal ligament: caudate process to kidney
- Lesser omentum: hepatoduodenal and hepatogastric attaches that need to be cut during sx
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What is the blood supply to the gallbladder?
cystic artery (from the hepatic artery)
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What are the bile ducts ? (3)
- hepatic ducts: draining canaliculi
- Cystic duct: connects gall bladder to hepatic ducts and common bile duct
- common bile duct: continuation of the cystic duct; opens to duodenum at major duodenal papilla
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Describe the difference in the major duodenal papilla between cats and dogs.
- Dogs- combined opening of the minor pancreatic duct and the common bile duct
- Cats- common bile duct joins major pancreatic duct before entering the duodenum (potentially why cats are more susceptible to colangiohepatitis)
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What is the most common cause of extra-hepatobiliary obstruction of the bile flow?
pancreatitis
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Describe the regenerative capacity of the liver.
can remove up to 70% of the normal liver and get enough compensatory hypertrophy and hyperplasia (makes more cells)
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What are pre-operative measures that should be taken with liver surgery?
- CBC/Chem/UA
- Bile acids (if no bile, cannot absorb fat)
- Coag profile (liver makes clotting factors- have vit K and plasma)
- Blood type (have blood ready in case hemorrhage)
- peri-operative fluids (correct fluid balance before sx)
- peri-operative antibiotics (ascending infections common anaerobic bacteria, gram -)
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What are some common peri-operative antibiotics before hepatic or biliary surgery?
- Unasyn
- Metronidazole
- Clindamycin
- Baytril
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What are mechanisms of post-operative bleeding after hepatobiliary sx? (4)
- decreased synthesis of clotting factors
- DIC
- vit K deficiency
- increased consumption of fibrinogen and clotting factors
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Post-operative bleeding after hepatobiliary sx is usually evident within ________.
5hr of sx
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What are the techniques for liver biopsy?
- percutaneous biopsy: tru-cut biopsy needle, +/- US or CT guided; don't get a very big sample, but can be good for high risk patients
- laparoscopic: midline approach with camera port, paramedian approach with instrument port; clamshell biopsy forceps; can visualize and watch hemostasis, bigger sample size
- open approaches: guillotine with monofilament absorbable suture (tears through parenchyma, pulls and ligates vessels), punch biopsy (biopsy periphery of necrotic lesions), partial liver lobectomy (dissect parenchyma, very bloody), complete lobectomy (remove at hilus, sometimes need to open chest/ cut diaphragm)
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Describe aspects and reasons for gallbladder aspirates. (5)
- 22-25G needle
- poke at avascular portion near fundus
- monitor site for leakage; can go through liver parenchyma so leaks into liver
- culture and cytology
- high vagal tone when you do this--> prepared to give atropine or glycopyrrolate
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Describe aspects of a cholecystectomy. (4)
- [gall bladder removal]
- always preferred to cholecystotomy
- dissection from hepatic fossa
- ligation of cystic artery and cystic duct
- assess patency of common bile duct
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Describe pain management after hepatobiliary sx. (4)
- opioids- fentanyl, methadone, buprenex
- epidural
- others- lidocaine, ketamine
- avoid NSAIDs (can lead to gastric issues, liver dz can have high gastrin levels naturally)
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What are indications for liver surgery? (8)
- PSS
- elevated bile acids
- arteriovenous malformation
- hepatopathy (chronic liver enzyme elevation)
- neoplasia
- cyst or abscess
- lobe torsion
- trauma (rare)
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What are indications for extrahepatic biliary surgery? (6)
- ***gallbladder mucocele (most common gall bladder dz in dogs)
- pancreatic disease
- cholelithiasis/ cholecystitis
- bile peritonitis (emergency)
- neoplasia
- extra-hepatic biliary obstruction
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What is necessary for life? (4 parts of the hepatobiliary system)
- portal vein
- biliary flow
- caudal vena cava
- 30% of liver
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Bile MUST...
- go to intestines
- if something is wrong at the intestine, reroute bile flow (attach gall bladder to intestines)
- if something is wrong at the gall bladder, take it out and make sure duct is patent
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