GI Surgery Flashcards
what perioperative antibiotic is used in all GI surgeries
cefazolin (high dose 1st generation cephalosporin)
used in simple GI sx:
- no septic abdomen
- no open bowel
- no spillage/perforation
when should broad spectrum antibiotics be used in GI surgery
perioperative and postoperative for:
- septic abdomen
- GI perforation
empiric: ampicillin + fluoroquinolone
- switch to specific Ab once culture and sensitivity comes back
what are the 4 criteria for assessing intestinal viability
- color
- pink, red, slightly purple - consistency
- thick or normal (NOT thin) - motility
- may or may not be motile
- motile guarantees viability - bleeding/perfusion
what layer of the GI wall must be perfused for the intestine to be viable
seromuscular layer
- must bleed when incised
mucosa can be poorly perfused and still have viable intestine - will slough off and regenerate eventually
what is the holding layer in all GIT regions
submucosa
what suture material should be used to close the GIT
absorbable monofilament
(PDS)
NEVER use cutting needles
gastric closure
2 layers
- mucosa + submucosa
- simple interrupted or continuous - muscularis + serosa
- inverted (lembert or Cushing)
small and large intestine closure
1 layer appositional
- simple interrupted or continuous
MUST include the submucosa in the closure but does not need to be full thickness (does not need to include mucosa)
- can be full thickness if unsure
characterstics of esophageal healing
SLOW due to:
- no serosa
- constant motion of the neck
- high tension area
- no omentum
what approach is used for esophageal surgery
cervical - ventral midline
cranial thoracic - L or R thoracotomy
caudal thoracic - L 7-9th intercostal
considerations for gastric surgery
- balfour retractors
- use packing to pad entire area
- stay sutures to elevate and manipulate stomach
can resect up to 75% of the stomach without affecting lumen size
most common gastric neoplasia
gastric carcinoma
causes diffuse thickening of gastric wall (US) + severe, intractable vomiting
what causes gastric ulceration
NSAID/corticosteroid use
hepatic disease
renal disease
neoplasia
blood supply of the jejunum
vascular arcades - makes for natural breakpoints for resection
duodenocolic ligament
located at the duodenal flexure where the descending duodenum turns into ascending duodenum
does NOT have substantial blood supply - can be incised
indication for small intestinal biopsies
chronic enteropathies
goal: sample multiple sites of the SI using a punch biopsy or full thickness (if indicated)
where should you incise into the intestine to remove a foreign body
aborad to the foreign body (healthy tissue)
orad segment will be inflammed/swollen
intestinal resection & anastomosis considerations
always plot out where on the arcades to make ligatures to ensure remaining vessels are well supplied
crushing clamps - most important; placed over the point of resection to separate healthy tissue from nonvital
noncrushing clamps - functions to block the flow of GI contents; placed 1-2 mm from resection site on the part of the body remaining in the body
always ligate on BOTH sides of the crushing clamp
how to handle luminal disparity during closure
place sutures on the large diameter segment at WIDER intervals and place sutures on the smaller diameter segment at NARROWER intervals
intestinal anastomosis technique
place 3 stay sutures at the mesenteric border to prevent loss of visualization
use simple interrupted sutures around the diameter, placing the first at the bottom of the circumference and the second at the top to ensure adequate apposition
always close the mesenteric rent (hole created in mesentery)
how to test the closure
pinch off segments orad and aborad to the anastamosis and inject saline to test for leakage
technique for removing linear foreign bodies
- remove the anchor at the tongue base or pylorus
- gastrotomy +/- enterotomy - remove the foreign body
- examine mesenteric border for perforations
- resect areas of perforations
- run the entire bowel to check for tension
intussusception
telescoping of one part of the bowel into another
occurs in YOUNG dogs/cats with underlying enteropathy
occurs in OLD dogs/cats with neoplasia
how to resolve intussuception
reduce the telescoping by milking the intussusceptum and pulling the intussuscipiens to remove
monitor for revascularization
risks of recto-colonic surgery
dehiscence
slower healing
less reliable blood supply
higher anaerobic bacterial load
more tension
vasa recta
many small vessels that branch off of the ileocolic and colic arteries to feed segments of the colon
cranial rectal artery
branch of the caudal mesenteric artery that supplies the distal colon
indications for colo-rectal resection
- colonic neoplasia
- feline megacolon
- rectal neoplasia
- colonic foreign bodies that do not pass
are full thickness biopsies indicated in colon
NO - can get full diagnostics with a scope
feline megacolon
idiopathic disturbance in the activation of smooth muscle myofilaments
signs:
- fecal tenesmus
- pain defecating
- vomiting
- anorexia
- dehydration
feline megacolon dx and tx
dx: radiographs - colon distension and fecal impaction
tx: subtotal colectomy - remove 95% of entire colon
is rectal neoplasia more common in dogs or cats
dogs
what is the most common rectal neoplasia in dogs
epithelial
- polyps
- carcinoma in situ
- adenocarcinoma
undergoes malignant transformation to gradually invade the wall
diagnosis of rectal neoplasia
if superficial and coming out of the rectum:
- FNA
- core biopsy
- incisional biopsy
if proximal:
- proctoscopy
- colonoscopy
mucosal eversion
retraction of the mucosal margins of the rectum using stay sutures
used for noninvasive (polyps) and superficial (caudal 1/3 of rectum) masses
indications for anal sacculectomy
- anal sac neoplasia - non-elective
- anal sacculitis, infection, impaction - elective
what kind of neoplasia affects the anal sac
apocrine gland adenocarcinoma
may need to do a lymphadenectomy as well
technique for anal sacculectomy
closed approach - incise over the sac and dissect from the outside
