Equine GI Surgery Flashcards
what is GI tract surgery in horses mostly related to?
signs of colic (abdominal pain)
what is GI surgery in horses occasionally for?
exploratory laparotomy or laparoscopy for subacute or chronic conditions or signs (e.g. weight loss, suspected masses, peritonitis)
what is the aim of a colic work up?
establishing whether a horse requires surgery or not
what is colic surgical decision making based on?
pain clinical exam findings rectal exam stomach tube abdominoscentesis blood work ultrasound
what findings on a colic work up would indicate there may be a need for surgery?
pain despite analgesia absence of faeces tachycardia poor MM colour reduced or no gut sounds distention or displacement of LI or SI increased PCV, TP and lactate positive reflux on NG tubing discoloured or turbid peritoneal fluid
what HR is classed as tachycardia in horses?
> 60 bpm
how much fluid on NG tubing is classed as abnormal / indicative of surgical colic?
more than 5L net
what is the likely cost of colic surgery?
around 4-8k
what sort of colic cases often result in high bills?
those that are unsucessful
what may be required up front to secure colic surgery?
substantial payment
what issues around transport are there associated with colic surgery?
where will the surgery be done and how will the horse get there
what is the prognosis for surgical colic cases?
hard to tell pre surgery
duration of signs and severity of systemic disturbance will give clues
what may aid in telling the prognosis of colic surgery cases?
duration of signs
severity of systemic disturbance
are complications following colic surgery common?
yes - owners should be made aware from the outset
what is key about preparation of a horse for colic surgery?
time is critical as it is an emergency so swift and efficient preparation is important
what is involved in the preparation of the horse for colic surgery?
jugular IV catheter placement decompression of stomach with NG tube administration of analgesia / antimicrobials IV fluids clip abdomen remove shoes and tape feet wash out mouth
what is the role of a jugular IV catheter?
administration of medication
IVFT
anaesthetic induction
what size IV catheter is used for an adult horse?
usually 14G
why should horses have their stomach decompressed prior to colic surgery?
cannot vomit and so refluxing will prevent gastric rupture of the stomach by decompressing
what may cause horses to reflux fluid on passage of an NG tube?
if there is obstruction or ileus of the SI
what does presence of reflux do?
helps diagnosis
when should horses stomachs be decompressed?
prior to anaesthesia induction
how will horse be restrained for passage of an NG tube?
stocks
twitch
sedation (Xylazine)
where is the NG tube passed through in the nose?
ventral meatus to avoid ethmoidial turbinates
why should the horses head be flexed when placing an NG tube?
allow passage of the tube into the oesophagus rather than the trachea
what will the horse do as an NG tube is advanced into the oesophagus?
swallow
how can correct placement of NG tube in the oesophagus be confirmed?
observe the left hand side of the neck for end of tube advancing in oesophagus to confirm correct placement
what should be done if spontaneous reflux doesn’t occur when an NG tube is passed?
establish siphon by attaching funnel to end of tube and pouring in a measured amount of water from a jug and then lowering the end of the tube into a bucket to collect and measure what comes out
why is IV fluid therapy needed when preparing a horse for colic surgery?
stabilise cardiovascular system and support circulation
when can the abdomen be clipped?
may be started before induction or left until horse is anaesthetised
what is the risk associated with clipping the abdomen before horses and anaesthetised?
may be safety issue if horse is painful and actively colicking
why do horses shoes need to be removed and their feet taped before surgery?
avoid trauma and damage to the recovery box
what must be done with the horses mouth before induction?
washed out to prevent debris being pushed into trachea at intubation
what must happen after induction when preparing a horse for a laparotomy?
Move from recovery box to table with hoist place urinary catheter clip abdomen (fine clip also) cover legs and feet drape prep skin in sterile manner lay out surgical colic kit
what position are horses usually placed in for exploratory laparotomy?
dorsal recumbancy
what must happen as well as placing a urinary catheter in male horses?
suture prepuce
what incision is made for an exploratory laparotomy?
ventral midline
what surgical kit is needed for colic?
check kit list
surgeons will have differing preferences
what are the main steps involved in surgical treatment of colic?
opening and exploration of the abdomen identification of lesion correction of displaced or entrapped intestine decompression of distended viscera resection if needed and anastomosis closure of abdomen recovery from anaesthesia
what are the main types of intestinal obstruction?
simple
functional
strangulating
describe simple intestinal obstruction
lumen only obstructed
vasculature ok so intestine is minimally compromised
what is the prognosis of simple intestinal obstruction?
good
what is an example of a simple intestinal obstruction?
pelvic flexure impaction
what causes a functional intestinal obstruction?
failure of peristalsis (e.g. ileus) leading to distention
what can cause functional intestinal obstruction?
grass sickness
post op complication of ileus secondary to distention
what happens during a strangulating intestinal obstruction?
compromise of vasculature leading to death (ischemia) of intestine
veins become obstructed causing oedema of gut wall
release of endotoxins into circulation
systemic compromise and shock
later secondary problems
what can cause strangulating intestinal obstruction?
pedunculated lipoma
large colon volvulus
what causes endotoxaemia in strangulating intestinal obstruction?
release of endotoxins into the circulation and peritoneal cavity due to oedema of intestinal wall that leads to increase in mucosa permeability
what results from endotoxaemia?
systemic compromise and shock
what is the prognosis of strangulating intestinal obstruction?
increasingly poor after 6-8 hours
what secondary problems may occur from strangulating intestinal obstruction?
laminitis
what does strangulating intestine look like?
goes from maroon to purple and then black as blood supply is compromised
what is the effect of SI strangulating obstructions on more proximal structures?
effect of a simple obstruction with distention as gas and fluid cannot pass the obstruction
what can be the result of prolonged distention of SI?
ileus
what will the intestine be like distal to strangulating obstruction?
appear relatively normal
what are the specific conditions that may lead to SI strangulating obstructions?
pedunculated lipomas
herniation (epiploic foramen, inguinal, mesenteric defects)
intussusceptions
how is an SI resection performed?
isolate affected (devitalised) segment with bowel clamps at either end
ligate blood vessels supplying the affected segmant
resect
what materials are used for anastomosis of the small intestine?
sutures or staples
what must be closed to prevent SI herniation once surgery is over?
defect in mysentery that comes from the SI resection