Principles Flashcards
What are four things that should be considered before gastrointestinal surgery?
Is the animal fit for GI surgery?
What is the risk of infection from GI bacteria?
How does the GIT heal?
Septic peritonitis - can be a major complication
What are the problems associated with gastric surgical diseases and gastric vomiting?
Loss of gastric hydochloric acid
- Metabolic alkalosis
- Hypochloraemia
Dehydration
- Poor tissue perfusion causing metabolic acidosis
Insufficient food intake
- Hypokalaemia
What can be caused by small intestinal complete obstructions that is a problem when wanting to undertake GI surgery?
Acute vomiting
What can be some problems associated with acute vomiting that need correcting before surgery?
High obstruction
- Mimics vomiting
Low obstruction
- Loss of pancreatic Na+ and HCO3-
- Causing metabolic acidosis
Dehydration
- Poor perfusion causing metabolic acidosis
Insufficient food intake and decreased absorption
- Hypokalaemia
What can a small intestinal partial obstruction cause that can complicate surgery?
Chronic vomiting
Diarrhoea
Weight loss
What should be done to correct problems caused by small intestinal partial obstructions, small intestinal complete obstructions and gastric vomiting?
Intravenous isotonic crystalloids
K+ supplementation provided
How should gastrointestinal bleeding problems be corrected prior to surgery?
Blood transfusions
Iron supplementation
What six things should be done to determine whether an animal is fit for anaesthesia and 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 indicated
Should we use prophylactic antibiotics for stomach surgery and why?
Antibiotics may not be necessary in healthy young dogs
If it is then a single broad spectrum antibiotic
Anaerobic coverage is recommended
Cephalosporin or amoxycillin-clavulante
Should we use prophylactic antibiotics for small intestine surgery and why?
Always use antibiotics
Single broad spectrum antibiotic
Anaerobic coverage
Cephalosporin or amoxycillin-clavulante
Should we use prophylactic antibiotics for colon surgery and why?
Always use antibiotics
Combination of 2 antibiotics
Antibiotic specifically targeted to anaerobes
Metronidazole plus cephalosporin/amoxycillin-clavulante
What are ways of decreasing bacterial contamination that isn’t antibiotics?
Isolate site of entry
Lavage wound after closure
Change gloves
Lavage abdomen
Use separate set of instruments for contaminated part
What are three things that need to be known about intestinal wound healing?
How quickly will it heal?
Is there a risk of breakdown?
- Higher in some animals?
How long is the wound strength dependent on sutures or staples used?
What is the strongest layer in the intestinal wall and why?
Submucosa
- High collagen content
Describe the process of intestinal wound healing
Haemostasis
- Days 1-4
- Platelet-fibrin clot formation
Inflammation
- Days 1-5
- Microbial killing
- Wound debridement
Proliferation/granulation
- Days 3-weeks
- Fibroblast proliferation
- Collagen synthesis
- Angiogenesis
Remodelling/maturation
- Weeks-years
Why is there a chance of intestinal wound breakdown during days 3-5?
Overlap between inflammation and proliferation
What happens to the rate of wound healing as you move along the GIT?
It decreases
Describe the rate of wound healing at each stage of the GIT
Stomach
- Rapid healing (abundant blood supply)
- Rarely complicated
Small intestine
- Day 14 regained 75-80% of normal strength
Large intestine
- Day 14 regained 50% of normal strength
- Greatest risk of wound breakdown
What five factors would impact negatively on intestinal wound healing?
Compromise to blood supply
Traumatic surgical technique (no electrocautery)
Hypoproteinaemia
- Can rarely be corrected before surgery
Chemotherapy/radiotherapy
- Delay for 3 weeks
Steroids
- Discontinue where possible
What are the three suture patterns used for repair of GI wounds and why are they chosen?
Full thickness appositional
Simple interrupted
Simple continuous
They restore normal anatomy and promote rapid healing
What type of suture material should be chosen and why?
Any material that is:
- Resistant to infection (monofilament)
- Retains its strength enough to permit healing
- Disappears after wound healing
Name two types of suture material are recommended for GI wounds. Which is preferred?
Monocryl and PDS II
What else can be used to repair GI wounds instead of suture material?
Metal staples
What is exploratory laparotomy?
Direct visual and tactile examination of the abdominal organs at surgery via an incision into the abdomen
When should exploratory laparotomy be carried out?
Diagnose the cause of intra-abdominal disease
Correct the cause of intra-abdominal disease
When should biopsies be taken and of which organs?
If no discrete lesion is found
Take biopsy of:
- Stomach
- Small intestine
- Liver
- Pancreas
- Enlarged lymph nodes
Describe the surgical approach for exploratory laparotomy
Ventral midline incision from the xiphisternum down to the pubis
In male would have to cut through preputial muscle
Retractors used to hold wound open
- Balfour retractors
- Gossett retractors
Describe an examination of the gastrointestinal tract through laparotomy and what you should have good knowledge of
Entire GI tract should be palpated
Run through hands in logical manner
Need knowledge of anatomy and blood supply
Describe gastrotomy repair
Repair in 2 layers
Mucosa and submucosa
- Simple continuous
Serosa and muscularis
- Simple continuous
- Inverting lembert (prevents leakage)
Describe a small intestine biopsy
Isolate intestine
Milk intestinal contents away
Close with atraumatic clamps/fingers
Incise along anti-mesenteric border
Biopsy ellipse cut with metzenbaum scissors
Why should you trim excess mucosa when repairing a small intestine biopsy?
To ensure sutures are placed through the submucosa
- 3-5mm apart
- 3-5mm from the cut edge
What should be done after releasing clamps in a small intestine biopsy?
Assess enterotomy for leaks
When should you do a large intestinal biopsy and why?
Never
- Unless a lesion is specifically identified or suspected
Increased risk of breakdown of a large intestine wound
When should a liver biopsy be carried out?
Clinical signs/blood tests suggestive of liver disease
Abnormal appearance on ultrasound
Abnormal appearance during surgery
Presence of liver nodules/masses
What should be considered before undertaking a liver biopsy?
Fine needle aspirates
Trucut biopsy under ultrasound guidance
What is the main complication with doing a liver biopsy?
Bleeding
- Use haemostats to crush blood supply
- Use electrocauterization to stop bleeding
Which part of the liver should you biopsy?
Tiny triangular segment along the edge of the liver
Pack with haematostatic agents
If a nodule is present then biopsy nodule instead
What are the two ways that gastic foreign bodies can be treated?
Endoscopic retrieval of foreign body
Gastrotomy
What should be provided with post-op care of a gastrotomy and what is the prognosis?
Feed
Antacids
Gastric protectants
Excellent prognosis
What should be decided before making surgery to correct a gastric neoplasia?
Are there any obvious metastases?
Is tumour resection and reconstruction achievable?
Can the cardia be preserved?
Can the common bile duct be preserved?
Can the pancreatic duct be preserved?
What is the prognosis of a gastric neoplasia?
Complete resection of benign tumour
- Good
Malignant tumour
- Poor
- Clinical symptoms often recurring within weeks
What type of closure should always be used partial gastrectomy?
Eversion - edges turned out
In what two instances is intestinal resection and anastomosis needed?
Ischaemic necrosis
Neoplasia
What should the GI tract be assessed for before surgery?
Pulsations in arterial blood vessels
Presence of peristaltic muscle contractions
Normal colour
Normal wall thickness on palpation
Describe intestinal resection
Milk out intestinal contents
Isolate intestine with atraumatic clamps
Ligate mesenteric vessels
Incise mesentery
Incise intestine close to clamps on intestine to be resected
What should be done with luminal disparity?
Sutures should be spaced further apart on the larger side
Transect the small side at an angle to match diameter of large side
Reduce small side with sutures
Spatulate small side
Describe how an end-to-end anastomosis should be carried out
Suture as for enterotomy
Place first suture in mesenteric border
Place second suture in anti-mesenteric border
Repair defect in mesentery
Describe how an intestinal wound is supported during end-to-end anastomosis
Omentalisation
Serosal patch
- Adjacent pieces of healthy are tacked to intestinal wound
What should be encouraged as soon as possible after enterotomy and enterectomy?
Encourage oral nutrition
What are some complications inolved with enterotomy and enterectomy?
Persistent ileus
Stricture at anastomosis site
Short-bowel syndrome
Intestinal incision dehiscence
What is the consequence of intestinal wound breakdown?
Septic peritonitis
What is the prognosis of spetic peritonitis?
Extremely guarded
50% mortality
Why can poor wound healing occur with oesophageal wounds?
Lack of a serosa
Segmental blood supply
Constant motion of swallowing and breathing
Lack of an omentum
Tension at the surgical site
What should be done medically as treatment prior to surgery for a vascular ring anomaly?
Slurry diet
Feed from a height
Maintain upright for 20 mins post feeding
Treat for aspiration pneumonia if required
Why is surgical exploration of oropharyngeal stick injury essential?
Assess and repair damaged structures
Remove any further stick material
Lavage the tissues
Collect samples
