Equine GI Surgery Flashcards
which condition is the most likely to be a cause for GI surgery in horses?
colic (abdominal pain)
what reasons other than colic might a horse need GI surgery?
exploratory laparotomy/laparoscopy
other subacute/chronic conditions e.g. weight loss, suspected masses, peritonitis
how might you establish whether the horse requires emergency surgery?
pain clinical exam findings rectal exam NGT reflux peritoneal fluid analysis blood work ultrasound findings
how might behaviour change in a horse with colic?
moderate/severe and persistent behavioural signs despite analgesia
how might faecal output change in a horse with colic?
horses with colic can usually produce no faeces
what heart rate is found in horses with colic?
> 60 bpm
what colour might mm be in horses with colic?
poor
what might happen to the rectum/intestines in horses with colic?
distension +/- displacement (SI or LI)
what might be found in blood testing in horses with colic?
Increased PCV/protein/lactate (indicative of dehydration)
what should happen when you NG tube a horse with colic?
positive reflux of more than 5L
what will an ultrasound show with colic?
distended SI or displaced LI
what is the fluid like on paracentesis if a horse has colic?
discoloured and turbid peritoneal fluid
where should a catheter be placed for colic surgery?
jugular intravenous for admin of medication, IV fluids, anaesthesia
what size catheter is usually used for an adult horse?
14G
how do you decompress the stomach?
passing a nasogastric tube (refluxing) - should be done before anaesthesia induction
how do you confirm correct placement of the NG reflux tube?
observe left hand side of the neck for end of tube advancing in oesophagus (critical!)
how do you insert the NG tube?
tube is passed into ventral nasal meatus
flex head to encourage passage into oesophagus rather than trachea
horse swallows as tube is advanced
what should you do if no spontaneous reflux establishes after passing the NG tube into the stomach?
create a syphon by attaching a funnel to end of tube and pouring in a measured amount of water from jug - lower end of tube into bucket to collect and measure what comes out
which medications might be administered to prepare a horse for colic surgery?
analgesia and antimicrobials
why are IV fluids administered during prep for colic surgery?
support circulation - stabilise cardiovascular system
how is the abdomen prepped for colic surgery?
clipping - may be started before induction but consider safety (horse is likely to be in a lot of pain)
what are the overall steps in preparing a horse for colic surgery?
jugular IV catheter placement
decompression of stomach with NG tube
administration of analgesia/antimicrobials
IV fluid to support circulation
clip abdomen
shoe removal/tape feet
wash out mouth
what steps should be taken to prepare the horse after induction?
move to table
place urinary catheter (suture prepuce in males)
clip abdomen/second fine clip
cover legs and feet
drape
sterile skin prep
ensure all instruments are in surgical colic kit
what are the main principles of surgical treatment?
opening and exploration of the abdomen by palpation and exteriorisation of intestine
identification of the lesion
correction of displaced/entrapped intestine
decompression of distended viscera
resection of devitalised tissue and restoration of intestinal continuity
closure of abdomen
recovery from anaesthesia
what are the 3 types of intestinal obstruction?
simple (lumen only obstructed)
functional
strangulating
what is a functional obstruction of the intestines?
peristalsis fails to propel ingesta, leading to distension
what is a strangulating intestinal obstruction?
compromise of vasculature resulting in ischaemia of intestine - veins obstructed leading to oedematous thickening of gut wall
what does a strangulating obstruction lead to?
release of endotoxins into circulation –> systemic compromise and shock (endotoxaemia)
what colour is a strangulating obstruction?
section does maroon to purple to black
how does the intestine distal to an obstruction look?
appears relatively normal
what specific conditions can cause strangulating obstruction?
pedunculated lipomas
herniation - epiploic foramen, inguinal, mesenteric defects
intusussceptions
how is small intestinal resection achieved?
isolation of affected segment with two bowel clamps at either end
ligation of blood vessels supplying affected segment
resection of affected segment
how are simple/functional obstructions treated?
decompression of SI and/or enterotomy to remove obstruction
blood supply not compromised so no resection or anastomosis required
what is the prognosis for simple/functional obstructions?
usually good once resolved
what is the prognosis for strangulating lesions involving resection/anastomosis?
survival to 1 year approx 50%
what are the risks involved in treating strangulating lesions?
contamination and peritonitis
endotoxic shock
ileus
post-operative adhesions
what are the most common conditions affecting the large intestine?
displacements
large colon torsion
enteroliths (not common in UK)
what is involved in surgical management of colonic displacement?
decompression of distended bowel
evacuation of colon via pelvic flexure
enterotomy (not always)
correction of displacement
colopexy occasionally performed
what is a colopexy?
anchoring the colon by suturing (usually to body wall)
what type of obstruction does a large colon volvulus tend to be?
strangulating obstruction with ischaemia of a huge section of GI tract
where does a large colon volvulus occur?
at sternal flexure or close to attachment of the right ventral colon to the caecum
what is the cause of large colon volvulus?
unknown
which horses are most commonly affected by large colon volvulus?
usually affects larger horses, particularly brood mares 90 days after foaling
what are the specific signs of large colon volvulus?
sudden onset severe abdominal pain
extremely enlarged colon
marked abdominal distension
endotoxaemia - systemic status deteriorates rapidly
tachycardia
poor peripheral perfusion
what is the prognosis for large colon volvulus?
directly related to the time that elapses between onset of condition and surgery
90% near brood mare farms but much lower when horse must be transported large distances
what is involved in post-operative care?
exam every 2-4 hours
analgesia, antimicrobials
IV fluid therapy
belly bandage
monitoring for complications
regular blood sampling
NG tubing as required
what are the potential post-operative complications?
endotoxaemia (esp post strangulating obstructions)
ileus
jugular thrombophlebitis
incisional infection
further obstruction
anastomosis leakage
peritonitis
adhesions
what parameters should be monitored post-op?
pain levels temperature GI signs CVS signs incision site catheter feet respiratory system
how can post-op pain be monitored?
behavioural signs of colic
heart rate (tachycardia)
specific - peritoneal, incisional infection, musculoskeletal (laminitis)
how can pyrexia be monitored for post-op?
rectal temperature
how can you measure GI function post-op?
reflux through NG tube faecal output gut sounds on auscultation appetite ultrasound
how can cardiovascular function be assessed post-op?
heart rate
mm colour and CRT
PCV, protein, lactate, electrolytes
what should you be looking for when checking an abdominal incision site?
swelling (some oedema is normal)
pain
discharge
what should you be looking for when checking a catheter post-op?
swelling
pain
jugular patency
why is it important to check the feet/mobility post-op?
laminitis can be secondary to endotoxaemia
how can you monitor the respiratory system post-op?
auscultation
increased rate?
nasal discharge/cough?
can you feed a horse who has post-op reflux on passing a NG tube?
no - nil by mouth, IV fluid therapy, may need to muzzle to prevent horse eating bedding
what should be involved in post-op feeding?
start with small volumes of water and gradually increase
grass is good first solid food
small wet mashes of concentrates
hay introduced as handfuls and gradually increased
return to normal volumes over 3 days (ish)
how should post-op exercise be managed?
box rest for 6 weeks with short walks to promote GI motility
check no incisional problems which may require prolonged exercise restriction
turn out into small paddock at 6 weeks
ridden exercise may resume 3 months if abdominal repair is sound
what are the potential immediate complications of GI surgery?
endotoxaemia
ileus
what are the potential short-term complications of colic surgery?
laminitis
jugular thrombophlebitis
what is the potential longer term complication of colic surgery?
adhesions
what are the signs of endotoxaemia?
tachycardia and tachypnoea
pyrexia –> hypothermia
hyperaemic mucous membranes, turning dark over time
colic signs, dullness
how is endotoxaemia treated?
IV fluid therapy
flunixin
polymixin B
hyperimmune plasma
how is ileus managed?
nasogastric intubation for gastric decompression
IV fluids (maintenance + dehydration + ongoing losses)
reassess 2-4 hourly
supplement with electrolytes if needed
how is laminitis treated?
frog support/deep bedding
analgesia
how is jugular thrombophlebitis treated?
remove catheter local anti-inflammatory treatment consider thrombolytics e.g. aspirin antibiotics? don't place catheter in other jugular - alternative site if venous access still required
how is peritonitis treated?
antibiotics - broad spectrum (often penicillin/gentamycin/metranidozole)
abdominal drainage +/- lavage?
what are the signs of colitis?
pyrexia, colic, diarrhoea
what can cause colitis?
can occur after colon torsion/displacement, where colon wall has been compromised
antibiotic and NSAID usage plus sudden change in management
how do you treat colitis?
can require intensive nursing IV fluid therapy analgesia (avoid NSAIDs) prostaglandin analogues probiotics
what are the signs of incisional infection?
excessive local oedema
pain on palpation
drainage of purulent material
how do you treat incisional infection?
antibiotics if horse systemically affected
culture for sensitivity
encourage drainage
tends to persist until suture material resorbs (6 weeks ish)
