Small animal GI surgery

Small animal GI surgery

1. Is the animal fit for surgery?

   • Give IV isotonic crystalloids prior if needed
     • Allow animal to correct acid-base balance
   • If vomiting a lot may be hypokalaemic
     • Give IV K+ supplementation prior if needed
   • Location of obstruction may compromise fitness for anaesthesia
   • Get a complete history
   • Complete physical exam
   • Check haematocrit and total protein
     • If blood loss has occurred:
       • Blood transfusion
       • Iron supplementation
         • If chronic to allow animal to make own blood cells

2. Reason for surgery

   • Gastric surgical disease
     • Gastric vomiting
   • Small intestinal complete obstruction
     • Acute vomiting
   • Small intestinal partial obstruction
     • Chronic vomiting, diarrhoea and weight loss
   • Gastrointestinal bleeding
     • Haematemesis
       • Partly digested blood in vomit
       • Coffee granule appearance
     • Melena
       • Blood in stool
       • Tarry

3. Risk of infection from GI bacteria

   • Low in stomach
     • Acid kills most enteric bacteria
   • Number of bacteria increases the further along the intestines
     • % of anaerobes increases
   • Antibiotics can be used prophylactically
     • May not decrease risk of infection
     • Should always be used in SI and colon surgery
       • Use a combination of 2 for colon as risk is higher
   • Immune defence may be compromised
     • Debilitated animals
     • GI injury
     • Surgeries > 90 mins
   • Septic peritonitis fatal in 50%

4. Methods for decreasing bacterial contamination

   • Isolate site of GI entry
   • Use separate set of instruments for contaminated part
   • Lavage GI wound after closure
   • Lavage abdo with sterile saline
   • Change gloves
   • Low residue diet
   • At least 12-24hr starvation

5. Healing of the GI

   • Submucosa - strongest layer in intestinal wall
     • Hig chollagen content
     • Most important layer for stitches to go through to close off wound
   • Rate of wound healing decreases along GI
     • Stomach
       • Rapid healing
       • Abundant blood supply
     • Small Intestine
       • Regain 80% normal tensile strength by day 14
     • Large Intestine
       • Regained 50% normal tensile strength by day 14
       • Increased collagenase production
       • Greatest risk of wound breakdown
   • Can be affected by:
     • Compromise to blood supply
     • Traumatic surgical technique
     • Hypoproteinaemia
     • Chemo & radiotherapy
     • Steroids
   • Use monofilament suture material to reduce bacterial load