Principles of Small Animal Gastrointestinal Surgery Flashcards
gastric vomiting - effects
Loss of gastric hydrochloric acid - Metabolic alkalosis, Hypochloraemia
Insufficient food intake - Hypokalaemia
Dehydration - Poor tissue perfusion, Metabolic acidosis
acute vomiting - effects
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
Chronic vomiting, diarrhoea + weight loss - effects
Dehydration & electrolyte loss
Bacterial proliferation & nutrient metabolism - Maldigestion & malabsorption, Intestinal mucosal damage
Diarrhoea - Weight loss, Hypoalbumninaemia
How to correct effects of vomiting (all types), diarrhoea + weight loss prior to surgery
intravenous isotonic crystalloids
intravenous K+ supplements
Gastrointestinal bleeding - haematemesis, melaena - effects
Anaemia - non/Regenerative
Hypoalbuminaemia
how to correct effects of GIT bleeding before surgery
blood transfusion
iron supplements
what to check to see if animal is fit for surgery
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
prophylactic antibiotics - stomach
may not be needed for healthy animal
single broad spec antibiotic with anaerobic coverage
cephalosporin or amoxycillin-clavulante
prophylactic antibiotics - small intestine
antibiotics always indicated
single broad spec antibiotic with anaerobic coverage
cephalosporin or amoxycillin-clavulante
prophylactic antibiotics - colon
antibiotics always indicated
combo of 2 antibiotics including 1 specifically for anaerobes
methods to decr bacterial contamination
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
methods to decr bacterial contamination - large intestine
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
strongest layer in intestinal wall + why
submucosa
high collagen content
1-4 days post surgery wound activity
Haemorrhage Platelet clot - Fibrin clot Inflammation Microbial killing potential wound debridement Epithelial migration No change in wound strength
3-14 days post surgery wound activity
Fibroblast proliferation
Collagen formation
incr wound strength
rate of wound healing - stomach
rapid due to large blood supply
healing rarely complicated
rate of wound healing - small intestine
by day 14, 75-80% normal strength
rate of wound healing - large intestine
By day 14, regained 50% of normal tensile
? Increased collagenase production
Risk of wound breakdown greatest
Factors which impact negatively on intestinal wound healing
Compromise to blood supply Traumatic surgical technique (electrocautery) hypoproteinaemia chemo + radiotherapy steroids
Repair of gastrointestinal wounds with sutures: Suture pattern + material choice
restore normal anatomy
promote rapid healing
multifilament material has crevices that trap bacteria
absorbable material - stays long enough to allow healing
Repair of gastrointestinal wounds with metal staples
Titanium staples: permanent, inert
Special gastrointestinal staple guns with staple cartridges
eversion or inversion of edges
exploratory laparotomy - indications
To diagnose the cause of intra-abdominal disease
To correct the cause of intra-abdominal disease
exam of GIT
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)
gastrotomy - define
incision into the stomach
gastrotomy - repair
Repair in 2 layers
Mucosa & submucosa - Simple continuous
Serosa & muscularis - Simple continuous, inverting lembert (prevent leakage)
small intestine biopsy
isolate intestine
milk intestinal contents away + close intestine with clamps
incise along anti-mesenteric border
ellipse for biopsy cut with metzenbaum scissorsd
large intestinal biopsy
Do not biopsy the large intestine unless a lesion is
specifically identified/suspected due to increased risk
of breakdown of a large intestine wound
liver biopsy
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
Gastric Foreign Bodies - Diagnosis
ultrasound
Gastric Foreign Bodies - treatment
Endoscopic retrieval of foreign body
Gastrotomy
Gastric Neoplasia - Decision Making Prior to Surgery
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?
gastric neoplasia - prognosis
Complete resection of benign tumour (leiomyoma) - good Malignant tumour (adenocarcinoma) - poor, clinical symptoms often recurring within weeks
partial gastrectomy
Same principles as gastrotomy
Consider the use of staples
assessing GIT viability
Pulsations in the arterial blood vessels
presence of peristaltic muscle contractions
normal colour
normal wall thickness on palpation
intestinal resection
similar to SI biopsy
ligate mesenteric vessels then incise mesentery
luminal disparity (size mismatch)`
`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
end-to-end anastomosis
Suturing as for enterotomy
Place 1st suture in mesenteric border
Place 2nd suture in anti-mesenteric border
Repair defect in mesentery
end-to-end anastomosis - support wound
omentalisation (wrap omentum around wound)
serosal patch - adjacent healthy intestine tacked to intestinal wound
intestinal foreign bodies - history
Persistent vomiting (frequently projectile)
Anorexia
Depression
No defaecation
intestinal foreign bodies - clinical exam
Dehydration Depression Abdominal Pain Intrabdominal mass String around tongue
intestinal neoplasia types
Adenoma/adenocarcinoma Lymphoma Leiomyoma/leiomyosarcoma mast cell Duodenal polyps
intestinal neoplasia - clinical signs
Partial obstruction
Chronic intermittent vomiting
Diarrhoea
Weight loss
intussusception - define
Invagination of one portion of the gastrointestinal tract
into the lumen of an adjoining segment
intussusception - clinical signs
palpable tubular mass dehydration depression abdominal pain protrusion of intussusception from anus
intussusception - diagnosis
ultrasound (parallel lines/concentric rings)
radiography (gas distenstion in SI)
intussusception - reduction or resection
Reduction: push rather than pull
Assess intestines
Resect if - Irreducible, Ischaemic / injured intestines, Mass present
further treatment for intussusception
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
Enterotomy & Enterectomy - Complications
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
The consequence of intestinal wound breakdown
septic peritonitis
50% mortality
septic peritonitis - clinical signs
vomiting Anorexia & depression Abdominal pain Abdominal enlargement Hypovolaemic shock Pyrexia Discharge from abdominal wound Diarrhoea Haematochezia, melaena, haematemesis
septic peritonitis - diagnosis
Abdominocentesis
most important test
septic peritonitis - treatment
Ex lap to find & correct leak
Peritoneal lavage + drainage
Intensive post-op care - Maintenance of normovolaemia &
blood pressure, nutrition is essential
