GI tract surgery Flashcards
Which of the following reasons as to why GI surgery would be performed are most likely to require emergency surgery?
A. Obstruction of GIT (complete)
B. Obstruction of GIT (partial)
C. Perforation of GIT
D. Strangulation of GIT vasculature
E. Structural/functional abnormality of GIT
F. Need biopsies for diagnosis
G. Need feeding tube
A. Obstruction of GIT (complete)
C. Perforation of GIT
D. Strangulation of GIT vasculature
Also volvulus or torsion
Dfdx for GIT obstruction
- Foreign body, neoplasia, intussusception, torsion/volvulus, anatomic anomaly, herniation, stricture, extramural compression
How can an obstruction lead to sepsis?
- Gas/fluid distension proximally
- Venous and lymphatic stasis in bowel wall
- Fluid moves into lumen and eventually across the serosa
- Bacteria/toxins move into circulation and across the serosa
- Ischemia/necrosis of the bowel wall may lead to perforation
Which ddx tend to have more acute onset and more severe signs?
- Complete obstruction compared to partial obstruction
- Orad obstruction compared to aborad obstruction
- Vascular compromise (as with strangulation or torsion) compared to just luminal obstruction
- FB obstruction as compared with neoplasia
What acid/base status can provide a clue that there is an obstruction proximal to the entry of bile into the GIT, and what is the pathophysiology?
- Vomit gastric secretions rich in K, Na, H, Cl
- Metabolic alkalosis
What acid/base status can provide a clue that there is an obstruction distal to the entry of bile into the GIT, and what is the pathophysiology?
- Vomit gastric and pancreatitis (HCO3) secretions
- Metabolic acidosis
Radiographic signs of obstruction (3)
a. Local intestinal distention, two populations of intestinal size
b. Stacked distended intestinal loops with hairpin turns
c. Small intestinal diameter >2x height of L5 body
WHat can lead to GIT perforation?
- Anything that damages bowel or its blood supply
- Causes include all causes of GIT obstruction, neoplasia, thrombosis, strangulation, ulceration, trauma, iatrogenic
What is the one specific circumstance when GIT perforation is NOT a surgical emergency?
- Small perforation in otherwise healthy tissue of the CERVICAL esophagus
Why is the cervical esophagus different than other sites in that a perforation there doesn’t warrant immediate surgery?
- That’s where we place esophagostomy tubes
What can happen with volvulus or torsion that warrants immediate surgery?
- Can cause obstruction of luminal organs
- In addition, whether an organ twists on itself or the mesentery of the organ twists, blood supply is compromised
Why are veins more susceptible to twisting with volvulus and torsion than arteries?
- They don’t have the muscular wall
What happens if blood can flow into an organ but not out?
- Organ gets congested, waste products cannot be removed
- new oxygenated blood can get in only to the point that the vasculature can expand to accommodate it (old blood is not flowing out to make room for new blood)
What can cause the rapid decline with volvulus/torsion?
- Tissue ischemia, shock (hypovolemic, circulatory, endotoxemic), multi-organ failure, and death
What happens with strangulation vs volvulus and torsion
- In strangulation, the vein and artery are both closed off
- In a volvulus or torsion, just the vein is closed off
Difference in clinical signs with strangulation
- Decline similarly to volvulus or torsion, but faster (peracute)
Other consequences of torsion or strangulation
- Vascular thrombosis
- Ileus
- Proliferation of bacteria with transmural migration and entry into circulation
What is reperfusion injury?
- Occurs if blood flow is re-established and can be fatal
What is the mechanism of reperfusion injury?
- Oxygen reacts with by-products of metabolism leading to free radicals
- Torsion/volvulus –> hypoxia nad poor perfusion –> anaerobic metabolism –> accumulate hypoxanthine and xanthine oxidase when oxygen is added –> reactive oxygen species like peroxide –> cell death
What is a consequence of reperfusion injury regarding how we remove certain organs?
- Organ is removed WITHOUT de-rotating if possible; doable for spleen or a liver lobe but not for the whole stomach or whole intestine
What by-products of metabolism does oxygen react with to form free radicals?
- Hypoxanthine and xanthine oxidase
Are most GI tumors malignant or benign?
malignant
What is the most common type of GI tumor in dogs?
- Adenocarcinoma
What is the most common type of GI tumor in cats?
Lymphoma or lymphosarcoma
Common sites for metastasis for GI tumors
- Lymph nodes, liver, and lungs
Prognosis for benign GI tumors
- Benign can be cured if resectable
Prognosis for malignant GI tumors
- many months to 1-2 years if resectable, poor if mets
Surgical plan for GI tumors
- Resect tumor with 4-8 cm or more of grossly normal GIT (or biopsy is no resectable)
- Biopsy local lymph nodes
What is the amount of jejunum that can be removed w.o getting short bowel syndrome?
Look it up
Local node examples
- Portal/hepatic nodes
- Pancreaticoduodenal nodes
- Mesenteric nodes
- Splenic nodes
- Gastric nodes
What is a Bilroth procedure?
- Involves removing the pylorus (i.e. pylorectomy) and various amount of stomach and duodenum on either side
-
What are some possible consequences to consider with a Bilroth procedure?
- They sometimes disrupt the common bile duct, which must then be re-routed by anastosmosing a hole made in the gallbladder and to a hole made in a piece of intestine that will reach up to the gallbladder
Etiology of pyloric stenosis
- Congenital
Etiology of pyloric hypertrophy
- Acquired
Age of dogs with pyloric stenosis
- Young > old
Age of dogs with pyloric hypertrophy
- middle aged to older
Breed that gets pyloric stenosis
- Brachycephalic dogs
- Siamese cats
Breeds that get Pyloric hypertrophy
- Small breed dogs
Contrast studies seen with benign pyloric outflow obstruction?
- Delayed emptying
- Thickened pyloric canal
- Filling defect at the pylorus
- Thickening can be seeno n ultrasound as well
What does definitive diagnosis of either pyloric stenosis or pyloric hypertrophy require?
- Full thickness biopsy
- Cannot make definitive diagnosis with imaging or from a mucosal biopsy as obtained from endsoscopy
Prognosis for pyloric stenosis or pyloric hypertrophy
- Good to excellent outcome in 85% with appropriate surgical treatment
What type of bacteria are normal inhabitants in the oral cavity?
- Gram positive, anaerobes
- Peridontitis can lead to increased gram negative species
What type of bacteria are normal inhabitants in the esophagus?
- Gram positives and anaerobes
What type of bacteria are normal inhabitants in the stomach?
- Insignificant
What type of bacteria are normal inhabitants in the small intestine?
- Gram positive transitioning to gram negative anaerobes as you go more aborad
What type of bacteria are normal inhabitants in the colon/rectum?
- Gram negative and anaerobes
What should you do before incising into the GI lumen?
- Complete non-contaminating procedures if prioritization allows
- Designate a region of the table for contaminated instruments
- Pack off the section of bowel to be incised with several layers of moist laparotomy pads
- Take steps to prevent spillage (e.g. stay sutures to elevate the stomach; Doyens on esophagus or intestine
How many clicks for Doyens?
- One click only!
In VTH, where do we place all instruments used after the bowel is opened?
- On a huck towel on the front of the instrument table
- When ready to convert to clean, we can roll up tehse instruments in the towel and easily pass them off to a non-sterile assistant
To perform an -otomy: incise full-thickness into a non-vascular portion of the tissue
- Describe the location of the non-vascular areas you will use to perform a gastrotomy
- Between the greater and lesser curvatures
To perform an -otomy: incise full-thickness into a non-vascular portion of the tissue
- Describe the location of the non-vascular areas you will use to perform an enterotomy in the duodenum
- Look it up
To perform an -otomy: incise full-thickness into a non-vascular portion of the tissue
- Describe the location of the non-vascular areas you will use to perform an enterotomy in the jejunum
- Look it up, but I think it’s the antimesenteric side
To perform an -otomy: incise full-thickness into a non-vascular portion of the tissue
- Describe the location of the non-vascular areas you will use to perform an enterotomy in the ileum
- Look it up
To perform an -otomy: incise full-thickness into a non-vascular portion of the tissue
- Describe the location of the non-vascular areas you will use to perform an eneterotomy in the colon
Look it up
Where do you incise into the lumen relative to the obstruction and why?
- Healthy tissue aborad usually to the foreign body on the antimesenteric side
- If you’re right where the FB is, that’s probably not the healthiest
How is a biopsy of the small intestine performed when removing a foreign body?
- Trimming with Metzenbaum scissors a full thickness piece of tissue off the edge of your otomy incision
Write the layers of the intestine
- Serosa
- Muscularis
- Submucosa
- Mucosa
Write the layers of the esophagus
- Mucosa
- Submucosa
- Muscularis with circular and longitudinal muscles
- Adventitia
What is the holding layer anywhere along the GIT?
- Submucosa
How do the layers of the esophagus differ from the rest of the GIT?
- Lacks a serosa
- Early fibrin sealing occurs more slowly than in other places
Stomach vs small intestine
- Absorbable or non-absorbable
- Absorbable for both
Stomach vs small intestine
- Mono or multifilament
- Monofilament
Suture size for gastrotomy vs enterotomy
- Small for both
- Maybe 2-0 or 3-0?
of layers for stomach closure pattern
2
- Cushing or simple continuous in first layer then Lembert or Cushing
Tissue layers enagged for stomach
- Serosa, muscularis, and submucosa in the first one
- Second one serosa and muscularis
Knot intra- or extra-luminal for gastrotomy closure?
- Extraluminal
of layers for enterotomy closure
1
Suture pattern for small intestine
- Approximating (simple continuous or interrupted)
Suture spacing for stomach vs SI
???
Suture tightness for stomach vs SI
????
What type of incision (longitudinal or transverse) is made for an enterotomy?
- Longitudinal
When can you use a transverse closure for an enterotomy?
- If the luminal diameter is small (e.g. ferret, some cats or small dogs
Pressure test after suturing - how to do?
- Inject sterile saline via 25 g needle through the wall at an angle so there is not a direct hole from the lumen to the outside while the bowel is still clamped off with Doyens or fingers and inject to physiologic pressure
Options for repair of leaks with enterotomy repair?
- More sutures, serosal patch, ECM bioscaffold
What do you do after the conclusion of the GI procedure before the clsoure?
A. Remove laparotomy pads from the patient
B. Remove contaminated instruments from the table
C. Change gloves
D. Lavage abdomen with warm saline 200-300 mL/kg
What prevents your sutured GI incision from leaking during the inflammatory/debridement phase?
- Blood clot!
- Sutures, maybe some swelling
What prevents you sutured GI incision from leaking during the repair phase?
- New tissue
Visualize yourself doing an eneterotomy and a gastrotomy from start to finish
- DO IT
Blood supply for the following:
- Esophagus
- Stomach
- Small intestine
- Colon
- Rectum
- Esophagus: SEgmental
- Stomach: Collateral
- Small intestine: arcadial
- Colon: segmental
- Rectum: segmental
Bacteria for the following
- Esophagus
- Stomach
- Small intestine
- Colon
- Rectum
- Oral cavity
- Esophagus: Lots
- Stomach: Lots
- Small intestine: fewer relative
- Colon: Lots
- Rectum: Lots
- Oral cavity: Lots
Intraluminal forces
- Esophagus
- Stomach
- Small intestine
- Colon
- Rectum
- Oral cavity
- Esophagus: Lots of force
- Stomach: Lots of volume
- Small intestine: Liquid chyme and not a lot of force
- Colon: Lots of force
- Rectum: Lots of force
- Oral cavity: Lots of force
Tension on closure
- Esophagus
- Stomach
- Small intestine
- Colon
- Rectum
- Oral cavity
- Esophagus: Higher tension
- Stomach: Less
- Small intestine: Less
- Colon: Higher
- Rectum: Higher
- Oral cavity: Higher tension
Access to omentum
- Esophagus
- Stomach
- Small intestine
- Colon
- Rectum
- Oral cavity
- Esophagus: NOt as much
- Stomach: Yes
- Small intestine: Yes
- Colon: Yes
- Rectum: yes
- Oral cavity: no
What does the omentum do for healing?
- Brings in blood supply
- Seal
- Physiologic drain
- Antibody factors
What is significant of segmental blood supply for healing?
If the main vessel on either end of the piece of bowel is damaged, significant ischemia may occur
Significance of arcadial blood supply for healing?
- If the main vessel is damaged, there is likely adequate collateral circulation to provide blood the the region of bowel directly served by teh damaged vessel
Which sections of GIT have arcadial blood supply?
- Jejunum and ileum
Which sections of GIT have segmental blood supply?
- Duodenum, colon, ileum, cecum, rectum, esophagus
What signs do you use to distinguish viable from non-viable GIT?
- Viable: pink, peristalsis, pulses
- Non-viable: opposite of that
How much of esophagus can be resected without consequences?
- 20-30% or <3-5 cm
Consequence of resecting more esophagus than 20-30%
- Not sure
How much of stomach can be resected without consequences?
- YOu just need a tube from the esophagus to the duodenum
Consequences of resecting more stomach
- Lose some digestive qualities or certain diets
How much of the duodenum can be resected without consequences?
- Consider the pancreatic and/or bile ducts
Consequences of resecting too much duodenum
- Might remove the bile or pancreatic ducts
- You need bile to live
How much of jejunum can be resected without consequences?
- 70-80% (up to 90%)
- Take it out if you’re concerned
How much of stomach can be resected without consequences? How does it differ in cats vs dogs?
- 70% in dogs
- 100% in cats
What happens if you resect more colon than 70% in dogs?
- Dogs can get get chronic diarrhea
How much of the rectum can be resected without consequences?
- +/- incontinent if you remove >4 cm total or if you remove the distal 1.5 cm
How long is the median time from surgery until a diagnosed leakage from intestinal anastomosis and why?
- It was 5 days on average
- Inflammation and debridement phase ends then, so you kick into the repair phase
Incidence of leakage from resection and anastomosis site
- 12-15%
Mortality rate if leakage occurs from an enterotomy site?
- 85%
Risk factors for leakage from enterotomy site
- Preop peritonitis
- Preop serum albumin <2.5 g/DL
- Intraop hypotension
Why place a feeding tube intra-op?
- Provide enteral feeding postop especially for patients with preop peritonitis, preop serum albumin <2.5 g/dL, and intraop hypotension
- Good nutritional plane preserves and increases GIT blood flow, prevents ulceration, stimulates immune system defenses, and stimulates wound repair
When placing a feeding tube, what are guidelines for how much of the GIT to use?
- Use as much as possible
Benefits of nasogastric tube and when can it be removed?
- Easy to place
- Remove at any time
Placement of esophagostomy tube and when can it be removed?
- Well tolerated and easy to place
- Can be removed immediately if you don’t need it
Feeding tube in the stomach
- Gastrostomy tube
Feeding tube in the jejunum
- Jejunostomy
How long must a feeding tube be in place for a jejunostomy or gastrostomy?
- 7-10 days
- Need an adhesion to form
- Like a fistulous tract
How do we close the hole from a jejunostomy or gastrostomy tube?
- Let it heal by second intention after pulling it out
- It’s a contaminated wound
Postop monitoring for GI sx
- TPR, MM, CRT, BP, pulse quality, pain, urination, defecation, vomiting, appetite, drinking, incision, activity, PCV/TP, glucose, BUN, lactate, etc.
Analgesia postop for GI sx
- Assume painful postop and preemptively give analgesics
- Avoid NSAIDs in general because they already have compromised GIT
Antibiotics - are they needed post-op?
- In an otherwise healthy patient with a clean-contaminated sx, I think not
Monitoring skin after surgery
- Monitor for redness, swelling, heat, pain, dehiscence, discharge
Activity levels postop for GI sx
- leash walk only, no running/jumping, no off-leash for 2 weeks
For oral cavity surgery:
Food composition?
- Usually normal
For esophageal surgery:
Food composition?
- Bland
For stomach surgery:
Food composition?
Bland diet
For small intestinal surgery:
Food composition?
Bland diet
For oral cavity surgery:
Food consistency?
- Meatballs (so that the animal can swallow them whole)
For esophagus surgery:
Food consistency?
- Gruel
For stomach or small intestinal surgery:
Food consistency?
- Doesn’t matter
- Because you are feeding small amounts (and thus not distending the stomach) and because the body quickly adds liquid to the food, starting consistency doesn’t matter
- By the time the food gets to the small intestine, it will be liquid; thus starting consistency doesn’t matter
Food amount and frequency?
- Variable
For esophageal surgery:
Food amount and frequency?
- SMall meals q4-8 hours
For stomach surgery:
Food amount and frequency?
- Small meals q4-8 hours
For small intestinal surgery:
Food amount and frequency?
- small meals q4-8 hours
For oral cavity surgery:
When to start transition to normal food consistency and type?
- Days to weeks to months depending
For esophagus surgery:
When to start transition to normal food consistency and type?
- ~1 week
For stomach surgery:
When to start transition to normal food consistency and type?
48-72 hours
For small intestinal surgery:
When to start transition to normal food consistency and type?
- 48-72 hours
What is a bland diet, and why is it important oftentimes after a GI sx?
- Bland (i.e. easily digested) food is often a good idea post GI sx, because of inflammation/irritation associated with the GI problem (e.g. FB obstruction) or because of an underlying GI disease
- Bland does NOT mean soft
- Dry crunchy dog food (e.g. dry I/D) can be bland, while soft food (e.g. gravy laden dog food) may not be bland
If a dog starts vomiting after transitioning to normal food?
- Is there a reason?
- Sucralfate
- Cerenia
- Pantoprazole
- Often hold off for 12 hours and try again
