Lesson 103 - SA Intestinal Surgery

Which factors contribute to luminal distention in complete intestinal obstruction?

1. gas accumulation

2. fluid accumulation related to hypersecretion in the gastrointestinal tract

3. fluid accumulation related to reduced absorption in the gastrointestinal tract

Experimental studies of dogs with intestinal obstruction showed selective intestinal mucosal ischemia when intraluminal pressure was?

higher than 40 mmHg

Fluid and electrolyte losses in intestinal obstruction may be the result of:

1. vomiting

2. diarrhea

3. fluid sequestration in the intestinal lumen

Vomiting in a dog with distal intestinal obstruction may result in:

metabolic acidosis

3 multiple choice options

Which antibiotic is recommended for prophylactic use in surgery on the large intestine?

cefoxitin

3 multiple choice options

Which characteristic is not used for assessment of intestinal viability?

wall thickness

3 multiple choice options

What may increase the possibility of dehiscence after enterotomy closure?

excessive mucosal eversion

3 multiple choice options

Cats with linear FB ingestion may be managed conservatively if they:

present soon after ingestion and have no signs of peritonitis

3 multiple choice options

Which approach is not recommended for enterotomy closure?

wound glue

3 multiple choice options

In patients with linear FBs, intestinal resection and anastomosis are recommended for treatment of:

1. multiple perforations and subsequent peritonitis

2. intestinal fibrosis and permanent plication

3. extensive intestinal wall compromise

How can you determine if small intestine is distended on radiographs?

diameter >1.6x the height of L5

A patient has been diagnosed with a mechanical foreign body obstruction. What surgical procedure will ideally be performed?

enterotomy

3 multiple choice options

When entering the intestinal lumen during surgery, what is the surgery procedure now considered?

clean-contaminated or contaminated procedure

When performing surgery on the upper or middle small intestine, what pre-surgical antibiotic should be administered?

first generation cephalosporin like cefazolin

When performing surgery on the distal small intestine or large intestine, what pre-surgical antibiotic should be administered?

1. second generation cephalosporins like cefoxitin

2. penicillin plus a beta-lactamase inhibitor (ampicillin plus sublactam)

When do we redose the presurgical antibiotic?

2 hours after the initial dose

When is intestinal biopsy indicated?

diagnose intestinal disease that have not been defined by other tests and typically thickening noted on ultrasound

What are the methods of biopsy for intestines?

1. endoscopy

2. ultrasonography

3. laparoscopy

4. laparotomy

What type of biopsy method is preferred?

full thickness biopsy taken during laparotomy

How do you obtain a biopsy sample?

1. longitudinal or transverse enterotomy

2. #11 scalpel blade starts the incision

3. metzenbaum scissors used to obtain the sample

4. close using simple interrupted sutures

What do you need to do before taking biopsy samples?

explore the entire abdomen thoroughly

What other samples can we take during laparotomy?

1. lymph nodes

2. liver

3. other tissues

When do you take samples of the lymph nodes or other structures in comparison to intestinal biopsy samples?

before gastric or intestinal procedures to prevent cross-contamination

What can cause intestinal obstruction?

1. foreign material

2. intestinal strangulation/torsion

3. tumor

What occurs with the intestine oral to a complete intra-luminal obstruction?

distends with gas and fluid

What makes up the gas that accumulates before a foreign body?

1. swallowed air

2. carbon dioxide formed from bicarbonate neutralization

3. organic gases from fermentation

What makes up the fluid that accumulates before a foreign body?

1. retention of ingested fluid in the intestinal lumen

2. secretion of normal fluids

How does intestinal obstruction affect the tissue?

1. circulation in the mucosa and submucosa is impaired

2. increase pressure in the bowel

3. oxygen consumption declines

4. arterio- venous shunting

5. mucosa becomes ischemic

6. full thickness wall necrosis may occur

What border tends to get perforated with linear foreign body?

mesenteric border

What clinical signs are seen with a proximal/high intestinal obstruction?

1. persistent vomiting

2. loss of gastric secretions

3. electrolyte imbalances

4. dehydration

What acid-base disturbance occurs with a proximal intestinal obstruction?

hypochloremic, hypokalemic, metabolic alkalosis

Which type of intestinal obstructions are harder to diagnose?

very high obstructions due to not having classic obstructive patttern on radiographs

What is the major cause of mortality with proximal intestinal obstruction?

severe hypovolemia and electrolyte disturbances

Why does proximal intestinal obstructions result in hypovolemia and electrolyte disturbances?

secretions and ingested fluid do not establish contact with jejunal and ileal mucosa for reabsorption

When do untreated patients with proximal intestinal obstructions die?

within 3-4 days

Where are distal intestinal obstructions located?

1. distal jejunum

2. ileum

3. ileocecal junction

What acid-base disturbance occurs due to distal intestinal obstructions?

varying degrees of metabolic acidosis

What are the clinical signs of distal intestinal obstructions?

1. intermittent anorexia

2. lethargy

3. diarrhea

4. occasional vomiting spanning several days or weeks

What is the pathogenesis of the signs of distal intestinal obstructions?

1. maldigestion and malabsorption of nutrients

2. diarrhea may be attributed to osmotic affects of unabsorbed substances and secretory activity of enterocytes

When do patients with distal intestinal obstruction tend to die?

may live for more than 3 weeks if water is available

What causes death with distal intestinal obstruction?

fluid loss and toxemia related to bacterial proliferation

How do you close the intestine after enterotomy?

1. appositional sutures

2. sutures are closer to the incision on mucosal side

3. sutures are further from incision on the serosal side

Why are appositional sutures used for enterotomy?

prevent inversion or eversion of the mucosa

When performing an enterotomy to remove a foreign body, the incision into the intestine should be ideally made at what location?

aboral to the foreign body

3 multiple choice options

Why do we try to cut aboral to the foreign body?

typically the healthiest tissue

Which border of the intestine do we make our incision for enterotomy?

along the antimesenteric border

How do linear foreign bodies cause peritonitis?

continued peristalsis causes the object to become taut, cut into the mucosa, and then lacerate the mesenteric border causing peritonitis

Where do you need to check when you suspect linear foreign body?

under the tongue

When do we perform intestinal resection and anastomosis?

extensive disease or necrosis of intestine

What is the first step of intestinal resection and anastomosis?

identify the tissues that need removal and the blood supply that you need to ligate

How do you hold up the intestine that you will be resecting?

have an assistant hold between two fingers on either side of the diseased segment or if no assistant then use special clamps that minimize trauma

Once you identified section of necrotic intestine, what is the first step of resection?

double ligate and transect the arcadial mesenteric vessels from the cranial mesenteric artery that are supplying the segment of resectable intestine

Once you have ligated the arcadial mesenteric vessels, what is the next step of resection?

double ligate and transect the terminal arcade vessels and vasa recta vessels within the mesenteric fat

Once you have ligated and transected all the vessels needed, what is the next step of resection?

gently milk the chyme from the lumen of the section getting resected and use fingers or non-crushing forceps to occlude the healthy intestinal lumen and clamps to crush the diseased portion

Once you have occluded the intestinal lumen, what is the next step of resection?

transect the intestine with either a scalpel blade or metzenbaum scissors along the outside of the forceps

When resecting intestine which portion keeps the clamps that you have applied?

diseased resected portion keeps the clamps on to help prevent spillage

What angle do you transect the intestines if they are the same diameter?

perpendicular incision

What angle do you transect the intestines if they are different diameters?

1. oblique on the smaller diameter side

2. perpendicular on the larger diameter side

If further correction for size disparity is needed, what can you do?

1. space sutures around the larger lumen slightly farther apart than the smaller lumen

2. remove a wedge from the antimesenteric border of the smaller segment

How do you make an oblique incision?

1. shorter end on antimesenteric side

2. longer end on mesenteric side

What would happen if you made the antimesenteric side longer when transecting intestine?

necrosis due to lack of blood supply

When closing the small intestine, or any section of the GI tract, what is the holding layer?

submucosa

3 multiple choice options

Once an intestinal segment is anastomosed, how do you check for leakage?

1. maintain luminal occlusion

2. moderately distend the lumen with sterile saline and apply gentle pressure

3. use hemostats to check for spacing between sutures

Why is a leak test not a perfect test for anastomosis?

it is subjective because all anastomoses can be made to leak if enough pressure is applied

What is the first phase of intestinal healing?

lag phase days 0-4 with inflammation and edema

What is the second phase of intestinal healing?

proliferative phase days 3-14 with rapid gain in wound strength

What is the third phase of intestinal healing?

maturation phase days 10-180 with collagen reorganization

What is the most likely time for dehisence?

days 3-5

Which of these may increase the possibility of dehiscence after enterotomy surgery?

excessive mucosal eversion

3 multiple choice options

Where are the most common locations for intussusception?

1. ileocolic junction

2. jejunojejunal

What causes intussusceptions?

hypermotility often associated with enteritis

What is intestinal volvulus vs torsion?

volvulus is twisting of the intestine causing obstruction and torsion is twisting of the intestine about the root of the mesentery

How does the intestine appear with torsion/volvulus?

dilated, edematous, discolored ranging from red to black

What is involved with intestinal torsion and volvulus?

1. decompress the intestine if necessary to allow derotation

2. allow the intestine to reperfuse and stabilize while exploring the abdomen

3. if the segment has severe necrosis, ideally do not derotate

How do we prevent recurrence with intestinal volvulus/torsion?

1. pexy of a section to another section or body wall

2. if intestinal resection is necessary then pexy is likely not indicated

Which of these can cause intestinal intussusception?

1. intestinal parasites

2. intestinal neoplasia

3. foreign body obstruction

4. increased GI motility