Hepatic Surgery

Question 1

where does the liver sit within the abdomen?

Answer 1

cranially, with 2/3rds of it mass to the RHS

Question 2

how is the liver divided?

Answer 2

4 lobes - left, right, caudate and quadrate

Question 3

what is the liver attached to?

Answer 3

diaphragm, right kidney, lesser curvature of the stomach and proximal duodenum

Question 4

which major vessel runs through the liver?

Answer 4

caudal vena cava - firmly attached to liver

Question 5

where does the liver receive blood from?

Answer 5

hepatic portal vein (from digestive tract and spleen) - 70-80%

hepatic artery - oxygenated blood - 20%

Question 6

where does the oxygen supply to the liver come from?

Answer 6

50% hepatic portal vein and 50% hepatic artery

Question 7

how does blood leave the liver?

Answer 7

drains into hepatic veins which exit at the dorsal border of the liver into the caudal vena cava

Question 8

what is one of the main challenges of hepatic surgery?

Answer 8

high vascularity of the liver

Question 9

when do we start to see clinical signs of hepatic impairment?

Answer 9

not until 70-80% of functional hepatic tissue is lost - large functional reserve

Question 10

what might we see if synthesis and clearance of proteins (albumin) is impaired?

Answer 10

albumin-bound drugs and anaesthetic agents, ascites

Question 11

what are the main functions of the liver?

Answer 11

synthesis and clearance of proteins (albumin)

metabolism of nutrients

production/activation of clotting factors

clearance of toxins (ammonia, drugs)

immunoregulation

GI function

storage - vitamins, fats, glycogen, copper

Question 12

what might occur as a result of impaired metabolism of nutrients?

Answer 12

hypoglycaemia, lethargy, weight loss

Question 13

what might occur as a result of impaired clearance of toxins?

Answer 13

excessive sensitivity to drugs, neurological signs, PUPD, anorexia, vomiting

Question 14

what might occur as a result of impaired production/activation of clotting factors?

Answer 14

clotting problems, haemorrhage

Question 15

what might occur as a result of impaired immunoregulation?

Answer 15

endotoxaemia, sepsis

Question 16

what might occur as a result of impaired GI function?

Answer 16

weight loss, diarrhoea

Question 17

what are some of the non-specific signs you might see with impaired liver function?

Answer 17

PUPD, lethargy, weight loss

Question 18

where are bile acids synthesised?

Answer 18

in the liver

Question 19

how are bile acids excreted?

Answer 19

into hepatic ducts - converge to form common bile duct

Question 20

what happens to bile when the body is not digesting?

Answer 20

bile drains from the liver and passes via the cystic duct to the gall bladder

Question 21

what happens to bile in the gallbladder?

Answer 21

storage and concentration

Question 22

how does bile exit the gallbladder?

Answer 22

flows out via the cystic duct to the common bile duct and into the duodenum

Question 23

what are the main functions of bile acids?

Answer 23

help with digestion and absorption of fat

neutralise gastric acid and inhibit gastric acid secretion to prevent intestinal ulceration

Question 24

what diagnostic testing might be carried out for suspected hepatic dyfunction?

Answer 24

blood testing - haematology, biochemistry, blood gas/electrolytes, dynamic bile acid testing

urinalysis

imaging - radiography, U/S, CT, MRI, scintigraphy

Question 25

how might we medically manage patients with hepatic dysfunction to help with stabilisation before surgery?

Answer 25

prescription diet oral abs oral lactulose

Question 26

what should be ascertained about the patients blood before surgery?

Answer 26

complete coagulation profile - platelet count, activated partial thromboplastin time, prothrombin time

Question 27

why should a complete coagulation profile be carried out before hepatic surgery?

Answer 27

hepatic insufficiency can lead to clotting abnormalities, which could exacerbate risk of haemorrhage

Question 28

how can we mitigate abnormal coagulation test results?

Answer 28

advisable to pre-treat patient with vitamin K or fresh frozen plasma

Question 29

why are abs indicated for hepatic surgery?

Answer 29

due to presence of of bacteria in liver and risk of endotoxaemia/sepsis

Question 30

what is an appropriate ab choice for a patient undergoing hepatic surgery?

Answer 30

broad-spectrum ab e.g. potentiated amoxycillin or 2nd gen cephalosporin (while awaiting C&S results from liver/bile/gallbladder)

Question 31

which types of drugs should be avoided in patients with hepatic insufficiency?

Answer 31

drugs than undergo hepatic metabolism

Question 32

what general patient care is important to consider in patients with hepatic insufficiency?

Answer 32

pupd - regular water replenishment and toileting trips anorexia - tempt to eat

Question 33

what are the different methods for liver biopsy?

Answer 33

u/s guided percutaneous FNA/tru-cut open surgical technique laparoscopic technique

Question 34

what is the advantage of open/laparoscopic liver biopsies?

Answer 34

more accurate yield a better sample allows for gross visualisation and examination of the abdominal organs

Question 35

what are the indications for a partial/complete hepatic lobectomy?

Answer 35

removal of benign/malignant masses, abscess, liver lobe torsion

Question 36

what are the risks of partial/complete hepatic lobectomy?

Answer 36

haemorrhage liver failure portal hypertension

Question 37

what is cholecystectomy?

Answer 37

removal of the gallbladder

Question 38

what is cholecystoenterostomy?

Answer 38

rerouting of the gallbladder into the duodenum

Question 39

what are the indications for cholecystectomy/cholecystoenterostomy?

Answer 39

biliary tract rupture and bile peritonitis diseases causing extrahepatic biliary tract obstruction e.g. gallbladder mucocele, choleliths, pancreatitis, neoplasia

Question 40

what are the main perioperative considerations during hepatic surgery?

Answer 40

hypotension - arterial line ideal hypothermia - often difficulty regulating temperature significant risk of haemorrhage even if coagulation abnormalities identified and mitigated IVFT throughout surgery care with premedication and induction choice - avoid heavy hepatic metabolism ventilation if facilities available perioperative abs indicated

Question 41

what are the post-operative care considerations after hepatic surgery?

Answer 41

intensive nursing required for critical animals pain scoring and adequate analgesia monitoring - physical parameters, BP, signs of haemorrhage, bile leakage minimum database - haem and biochem abs if infection present nutrition - prescription liver diet monitor for sepsis/SIRS

Question 42

what is a portosystemic shunt?

Answer 42

an anomalous blood vessel which connects the hepatic portal vein with the systemic venous circulation, thereby passing the liver and diverting some of the portal blood supply away from the liver

Question 43

what can occur as a result of poor liver development due to PSS?

Answer 43

reduced protein production altered fat and protein metabolism reticuloendothelial dysfunction

Question 44

how long should a patient be starved for a bile acid stim test?

Answer 44

at least 12 hours

Question 45

how long should be left inbetween the pre-prandial and postprandial blood samples in a bile acid stim test?

Answer 45

as close to 2 hours as possible

Question 46

what diet should be fed to patients with PSS?

Answer 46

highly digestible high biological value of protein fatty acids, vitamins and minerals to meet the minimum requirements of the individual e.g. purina HP, royal canin hepatic, hills l/d

Question 47

why should patients undergoing corrective PSS surgery be starved for no longer than 8 hours?

Answer 47

due to reduced glycogenolysis and gluconeogenesis reserve

Question 48

why should patients undergoing corrective PSS surgery have a peripheral and central IVC placed?

Answer 48

peripheral for drug admin and IVFT central for blood sampling, glucose monitoring

Question 49

what blood parameter should be measured very regularly/closely during PSS surgery?

Answer 49

blood glucose - predisposition to hypoglycaemia, often paediatric patients

Question 50

how can we reduce risk of complications due to haemorrhage during PSS surgery?

Answer 50

ascertain clotting times pre-surgery blood cross matching and correct blood type available for transfusion

Question 51

why is it advantageous to have access to sympathomimetics during PSS surgery?

Answer 51

hypotension likely unresponsive to fluid therapy reduced proteins in blood due to impaired liver function means blood has less oncotic pressure - fluids given are rapidly lost to the extravascular space

Question 52

what should we be monitoring after after the PSS has been occluded?

Answer 52

portal hypertension

Question 53

what post-operative monitoring is required after PSS surgery?

Answer 53

ideally ICU-level nursing - often not possible temperature - prone to hypothermia, shivering will use up glucose unnecessarily blood pressure (15-30 min intervals) - colloids helpful part of IVFT if unresponsive to crystalloids glucose monitoring every hour until patient awake pain score hourly, analgese accordingly (no NSAIDs)

Question 54

which type of drug should be avoided in patients who have had PSS corrective surgery?

Answer 54

NSAIDs - risk of GI ulceration associated with portal hypertension