Surgery Abdo Module 1

Question 1

What are classifications of wounds at surgery?

Answer 1

Clean: non-traumatic, uninfected operative wounds that only involve skin and musculoskeletal soft tissues

*Prophylactic abs in clean contaminated or worse

Clean-contaminated: Operative wounds where a hollow viscus (GIT/Resp/Urinary tract) is opened in a controlled manner with no spillage or contamination of surrounding tissues

Contaminated: During surgery bacteria has entered a normally sterile environement but for too brieg a period to allow infection to become established (leakage of intestinal contents into abdo cavity)

Dirty: Surgery is carried out to control an established infection (peritonitis/total ear canal abalation)

Question 2

What are predictors of SSI?

Answer 2

1. Wound classification system (clean, clean-contaminated, contaminated, dirty)
2. Operative technique
3. Length of surgery - 30% greater risk of infection with each hour of surgery
4. Health of the patient

Question 3

What is the MIC breakpoint?

Answer 3

the chosen concentration of an antimicrobial which indicates whether a species of bacteria is susceptible or resistant to the antimicrobial

Question 4

What are the 5 regions the abdomen can be divided into for exploration?

Answer 4

1. Cranial abdomen
2. Caudal abdomen
3. GIT
4. Right paravertebral region
5. Left paravertebral region

Question 5

What are Halsted 6 surgical principles

Answer 5

1. Asepsis and aseptic surgical technique: patient prep, surgical approach
2. Sharp anatomic dissection - transecting ligaments and falciform fat to improve exposure
3. Atraumatic tissue handling and surgical technique - stay sutures, haemostasis, lavage and suction, correct instruments, preventing tissue dessication,
4. Removal of devitalised tissue from the surgical wound - lavage, packing off and isolating organs, regloving to close
5. Haemostasis and preservation of bloody supply to tissues - packing off and allowing normal haemostatic process v. active stoppage by ligating/monopolar/bipolar
6. Accurate tissue apposition, minimising tissue dead space without excess tension on tissue
   - when closing abdo peritoneum inclusion not recommended
   - choosing the right suture material for the closure
   - correct knots and sutures

Question 6

What are the layers of the GIT

Answer 6

1. Mucosa
2. Submucosa - important suture holding layer
3. Muscularis - smooth muscle
4. Serosa

Question 7

What are the stages of GIT healing

Answer 7

Lag phase: 1-3/4 days fibrin clot stage, minimal strength but will prevent some leakage - most likely stage to break down (72-96hrs)

Proliferation phase: 3/4-14 days fibroblasts causing epithelial migration and increased wound strength and immature collagen

Maturation phase: 14-180 days, less clinical importance reorganisation and remodelling of collagen

Question 8

What can the omentum be used for?

Answer 8

helps to seal leaks
helps bring nutrients and lymphatic drainage
sutures v. wrapping

Question 9

What is the use of serosal patching?

Answer 9

• Useful in reinforcing and sealing intestinal wounds where leakage is anticipated
• Good where multiple GI wounds are present in the
  intestinal tract or used following perforation and necrosis
• Reinforces seromuscular and submucosal layer which provides resistance to intraluminal pressures

Question 10

How to carry out an enterotomy

Answer 10

1. Exteriorise bowel to be incised and pack off from abdominal cavity
2. Milk away contents cranially and caudally
3. Incision is made distal to the obstruction: longitudinal incision with 15 blade in the antimesenteric portion of the intestine
4. With eliptical biopsy cats need transverse closure
5. Serosal patching

Question 11

Closing an enterectomy

Answer 11

• Sutures on mesenteric and anti-mesenteric border and then simple continuous
• cats: simple interrupted to avoid purse string sutures

Disparity of the lumens:
- spatulating smaller lumen at antimesenteric border
- larger lumen be partially closed with a simple continuous pattern until to matches that of remaining colon or proximal duodenum

Question 12

What are alternatives to suturing GIT

Answer 12

• Stapling devices
  
  • main advantage of stapling is the ease in which c
    intestine of different diameters can be
    anastomised
  • less tissue manipulation
  • no difference in wound bursting strength or
    absolute strength
  • same disadvantages as hand suturing: leakage,
    abscess formation, late FB obstruction at staple
    site
  • larger dogs
  • reduced surgical time

Question 13

What are causes of small bowel obstruction

Answer 13

Intraluminal, Intramural, Extramural
1. FB
2. Tumors
3. Strictures due to trauma/prior surgery
4. Intussusception
5. Strangulation
6. Abscesses
7. Adhesions

Question 14

Pathophysiology of invagination and causes

Answer 14

Invagination of a portion of intestine due to vigorous contraction of one segment into a relaxed segment.

Causes: young dogs: parasitism due to enteritis, older dog: neoplasia

Blood supply to intussuscepted portion of intestine is compromised due to inclusion in invagination. Initially venous occlusion with edema of the bowek and if prolonged arterial occlusion and necrosis
Eventually fibrous adhesions can form making spontaneous or surgical reduction difficult

following surgery can recurr up to 20% with 72hrs of procedure

Question 15

Prognostic factors useful for GDV

Answer 15

1. Lactate reduction with stabilisation - if doesnt drop or persistently high = poor prognosis (particularly 12hrs)
2. Radiographs: dilation v. GDV
3. Free abdominal air on x-ray - signs of necrosis
4. Thoracic rads: cardiomegaly - poorer prognosis

Question 16

GDV Patient Stabilisation

Answer 16

1. Stomach decompression/stomach tube - prolonged dilation = gastric necrosis
2. Fluid therapy : restoring circulation and this to improve tissue and oxygen perfusions - hypertonic saline/colloids (follow with crystalloids 20ml/kg/h)
   -contraindicated saphenous veins (gastric compression of the vena cava)
3. Pain relief - methadone 0.1-0.3mg/kg
4. Antibiotics - IV cefuroxime/co-amox
5. Anti-arrhythmia therapy: VPCs (runs of >20) and V-tach(160hr) or R on T phenomenon (usually begin intra or post op)
   - Lidocaine - bolus 2mg/kg IV, repeated up to
   8mg/kg IF sinus rhythm does not develop
   - CRI 25-75mcg/kg/min
   - Lidocaine tox: tremors, vomiting, seizures
   Potassium needs to be normal or lidocaine will be ineffective
6. Pre-oxygenate

Newer options/minimal published data
1. Corticosteroids: no published evidence - perceived effects antioxidant effect, increased vascular tone and positive inotropic effect
2. Deferoxamine and allopurinol - free radical scavengers

Paracetamol after stable and post surgery
No NSAIDs

Question 17

Options for gastric decompression

Answer 17

1. Percutaneous needle decompression
   - Clip and aseptically prep right lateral abdomen
   - A 14, 16, 18G needle
   - Rapid decompression to decrease caudal vena
   cava pressure
2. Stomach tubing (orogastric intubation)
   - Measure rhinum to 11th rib and mark - do not
   pass due to chance of necrosis
   - Attempt to pass in sitting or right lateral
   - Adhesive bandage roll placed in mouth and then
   mouth taped closed over this improvised gag
   - Pass stomach tube down the core of roll
   - Rotate the tube as introducing
   - Gastric lavage can be carried out with copious
   volumes of saline/hartmanns warmed

Question 18

What are the goals of GDV surgery?

Answer 18

1. Restore the anatomy by derotation of the stomach
2. Assess gastric and splenic viability and manage appropriately if there is necrosis
3. Prevent recurrence by performing a gastropexy

Question 19

What is the surgical approach to a GDV?

Answer 19

1. Midline laparatomy
2. Establish the direction of gastric rotation
   
   • Greater omentum covering stomach = clockwise
     rotation
     - Confirm this with palpation of the gastro-
     esophageal junction
     - Lift the pylorus gently to the right whilst pushing
     down on the fundas to the left
     - Decompress stomach further - gastrotomy to
     remove contents contraindicated
3. Gastropexy
   - Incisional gastropexy: incision on pyloric antrum and then one on the wall of abdomen, PDS suture
   - Belt loop gastropexy
   - Midline gastropexy

Question 20

How do you assess gastric/splenic viability?

Answer 20

Color - black/blue/green/black
Touch - friability
Pulses
Bleeding

The greater curvature and fundus are most likely to be ischaemic
Gastrectomy without stapling device - 60% mortality
Invagination is an option - meleana to be expected

Question 21

GDV post op care

Answer 21

1. Nutrition: Food and water can be introduced after
   12 hrs, 3-4 meals daily
2. Electrolytes: Hypokalaemia
3. Arrhythmias - oral procainamide or Sotalol
4. Pro-kinetic agents: metaclop/cisapride/erythromycin
5. Gastro-protectants: sucralfate/omeprazole

Question 22

Types of peritonitis

Answer 22

Primary peritonitis - no obvious source of contamination, haematogenous spread of bacteria - FIP

Secondary peritonitis:
- Septic (GI rupture/perforation/dehisence, penetrating trauma, blunt trauma, AI drugs, FB rupture)
- Aseptic: sterile mechanial or chemical irritation of the peritoneal cavity (pancreatic enzymes, gastric enzymes, talcum powder from gloves, barium, urine/bile, fb)

localised/generalised peritonitis