Principles of Small Animal Gastrointestinal Surgery

Question 1

gastric vomiting - effects

Answer 1

Loss of gastric hydrochloric acid - Metabolic alkalosis, Hypochloraemia
Insufficient food intake - Hypokalaemia
Dehydration - Poor tissue perfusion, Metabolic acidosis

Question 2

acute vomiting - effects

Answer 2

Low intestinal obstruction - Loss of pancreatic Na +
, HCO3-, Metabolic acidosis, ↓Na+
Dehydration - Poor tissue perfusion, Metabolic acidosis
High intestinal obstruction - Mimics gastric vomiting
Insufficient food intake & ↓absorption - Hypokalaemia

Question 3

Chronic vomiting, diarrhoea + weight loss - effects

Answer 3

Dehydration & electrolyte loss
Bacterial proliferation & nutrient metabolism - Maldigestion & malabsorption, Intestinal mucosal damage
Diarrhoea - Weight loss, Hypoalbumninaemia

Question 4

How to correct effects of vomiting (all types), diarrhoea + weight loss prior to surgery

Answer 4

intravenous isotonic crystalloids

intravenous K+ supplements

Question 5

Gastrointestinal bleeding - haematemesis, melaena - effects

Answer 5

Anaemia - non/Regenerative

Hypoalbuminaemia

Question 6

how to correct effects of GIT bleeding before surgery

Answer 6

blood transfusion

iron supplements

Question 7

what to check to see if animal is fit for surgery

Answer 7

Complete history
Complete physical examination
Check haematocrit and total protein 
Check electrolytes: K+and Na+
check acid-base status
Complete haematology and biochemistry: if clinically indicated

Question 8

prophylactic antibiotics - stomach

Answer 8

may not be needed for healthy animal
single broad spec antibiotic with anaerobic coverage
cephalosporin or amoxycillin-clavulante

Question 9

prophylactic antibiotics - small intestine

Answer 9

antibiotics always indicated
single broad spec antibiotic with anaerobic coverage
cephalosporin or amoxycillin-clavulante

Question 10

prophylactic antibiotics - colon

Answer 10

antibiotics always indicated

combo of 2 antibiotics including 1 specifically for anaerobes

Question 11

methods to decr bacterial contamination

Answer 11

Isolate the site of GI entry
Lavage GI wound after closure
Change gloves
Lavage abdomen with sterile saline
use separate set of instruments for contaminated part of surgery

Question 12

methods to decr bacterial contamination - large intestine

Answer 12

mechanical preperation
No evidence to support use in veterinary medicine
Liquid faeces maybe more likely to bypass atraumatic clamps and purse string sutures
A low residue diet & at least 12-24 hr starvation recommended

Question 13

strongest layer in intestinal wall + why

Answer 13

submucosa

high collagen content

Question 14

1-4 days post surgery wound activity

Answer 14

Haemorrhage 
Platelet clot - Fibrin clot
Inflammation 
Microbial killing
potential wound debridement
Epithelial migration
No change in wound strength

Question 15

3-14 days post surgery wound activity

Answer 15

Fibroblast proliferation
Collagen formation
incr wound strength

Question 16

rate of wound healing - stomach

Answer 16

rapid due to large blood supply

healing rarely complicated

Question 17

rate of wound healing - small intestine

Answer 17

by day 14, 75-80% normal strength

Question 18

rate of wound healing - large intestine

Answer 18

By day 14, regained 50% of normal tensile
? Increased collagenase production
Risk of wound breakdown greatest

Question 19

Factors which impact negatively on intestinal wound healing

Answer 19

Compromise to blood supply
Traumatic surgical technique (electrocautery)
hypoproteinaemia
chemo + radiotherapy
steroids

Question 20

Repair of gastrointestinal wounds with sutures: Suture pattern + material choice

Answer 20

restore normal anatomy
promote rapid healing
multifilament material has crevices that trap bacteria
absorbable material - stays long enough to allow healing

Question 21

Repair of gastrointestinal wounds with metal staples

Answer 21

Titanium staples: permanent, inert
Special gastrointestinal staple guns with staple cartridges
eversion or inversion of edges

Question 22

exploratory laparotomy - indications

Answer 22

To diagnose the cause of intra-abdominal disease

To correct the cause of intra-abdominal disease

Question 23

exam of GIT

Answer 23

entire GIT should be palpated and run through your hands in a logical manner
important to have good knowledge of anatomy + blood supply (know which blood vessels can be
safely ligated + to avoid damaging the blood supply to
vital organs)

Question 24

gastrotomy - define

Answer 24

incision into the stomach

Question 25

gastrotomy - repair

Answer 25

Repair in 2 layers Mucosa & submucosa - Simple continuous Serosa & muscularis - Simple continuous, inverting lembert (prevent leakage)

Question 26

small intestine biopsy

Answer 26

isolate intestine milk intestinal contents away + close intestine with clamps incise along anti-mesenteric border ellipse for biopsy cut with metzenbaum scissorsd

Question 27

large intestinal biopsy

Answer 27

Do not biopsy the large intestine unless a lesion is specifically identified/suspected due to increased risk of breakdown of a large intestine wound

Question 28

liver biopsy

Answer 28

Clinical signs + blood tests results suggestive of liver disease Generalised abnormal appearance on ultrasound or at surgery Presence of liver nodules or liver masses First consider fine needle aspirates and trucut biopsy of the liver under ultrasound guidance

Question 29

Gastric Foreign Bodies - Diagnosis

Answer 29

ultrasound

Question 30

Gastric Foreign Bodies - treatment

Answer 30

Endoscopic retrieval of foreign body | Gastrotomy

Question 31

Gastric Neoplasia - Decision Making Prior to Surgery

Answer 31

Is tumour resection and reconstruction achievable? A large proportion of the stomach can be resected but cardia must be preserved Can the common bile + pancreatic duct be preserved?

Question 32

gastric neoplasia - prognosis

Answer 32

``` Complete resection of benign tumour (leiomyoma) - good Malignant tumour (adenocarcinoma) - poor, clinical symptoms often recurring within weeks ```

Question 33

partial gastrectomy

Answer 33

Same principles as gastrotomy | Consider the use of staples

Question 34

assessing GIT viability

Answer 34

Pulsations in the arterial blood vessels presence of peristaltic muscle contractions normal colour normal wall thickness on palpation

Question 35

intestinal resection

Answer 35

similar to SI biopsy | ligate mesenteric vessels then incise mesentery

Question 36

luminal disparity (size mismatch)`

Answer 36

`Space sutures further apart on large side Transect the small side at an angle to match diameter of large side reduce small side with sutures spatulate small side

Question 37

end-to-end anastomosis

Answer 37

Suturing as for enterotomy Place 1st suture in mesenteric border Place 2nd suture in anti-mesenteric border Repair defect in mesentery

Question 38

end-to-end anastomosis - support wound

Answer 38

omentalisation (wrap omentum around wound) | serosal patch - adjacent healthy intestine tacked to intestinal wound

Question 39

intestinal foreign bodies - history

Answer 39

Persistent vomiting (frequently projectile) Anorexia Depression No defaecation

Question 40

intestinal foreign bodies - clinical exam

Answer 40

``` Dehydration Depression Abdominal Pain Intrabdominal mass String around tongue ```

Question 41

intestinal neoplasia types

Answer 41

``` Adenoma/adenocarcinoma Lymphoma Leiomyoma/leiomyosarcoma mast cell Duodenal polyps ```

Question 42

intestinal neoplasia - clinical signs

Answer 42

Partial obstruction Chronic intermittent vomiting Diarrhoea Weight loss

Question 43

intussusception - define

Answer 43

Invagination of one portion of the gastrointestinal tract | into the lumen of an adjoining segment

Question 44

intussusception - clinical signs

Answer 44

``` palpable tubular mass dehydration depression abdominal pain protrusion of intussusception from anus ```

Question 45

intussusception - diagnosis

Answer 45

ultrasound (parallel lines/concentric rings) | radiography (gas distenstion in SI)

Question 46

intussusception - reduction or resection

Answer 46

Reduction: push rather than pull Assess intestines Resect if - Irreducible, Ischaemic / injured intestines, Mass present

Question 47

further treatment for intussusception

Answer 47

Enteroplication (suture loops of intestine together) Treat underlying disease Always check for faecal bacteria and parasites: deworm if in doubt Prognosis - Good in young, 6-27% recurrence

Question 48

Enterotomy & Enterectomy - Complications

Answer 48

Persistent ileus - Vomiting, diarrhoea, pain, abdo distension Stricture at anastomosis site - Partial obstruction Short-bowel syndrome: >70% resection - Malabsorption & malnutrition Intestinal incision dehiscence - 7-16% for intestinal biopsies

Question 49

The consequence of intestinal wound breakdown

Answer 49

septic peritonitis | 50% mortality

Question 50

septic peritonitis - clinical signs

Answer 50

``` vomiting Anorexia & depression Abdominal pain Abdominal enlargement Hypovolaemic shock Pyrexia Discharge from abdominal wound Diarrhoea Haematochezia, melaena, haematemesis ```

Question 51

septic peritonitis - diagnosis

Answer 51

Abdominocentesis | most important test

Question 52

septic peritonitis - treatment

Answer 52

Ex lap to find & correct leak Peritoneal lavage + drainage Intensive post-op care - Maintenance of normovolaemia & blood pressure, nutrition is essential