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Flashcards in Equine GI Surgery Deck (148)
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1
Q

what is GI tract surgery in horses mostly related to?

A

signs of colic (abdominal pain)

2
Q

what is GI surgery in horses occasionally for?

A

exploratory laparotomy or laparoscopy for subacute or chronic conditions or signs (e.g. weight loss, suspected masses, peritonitis)

3
Q

what is the aim of a colic work up?

A

establishing whether a horse requires surgery or not

4
Q

what is colic surgical decision making based on?

A
pain
clinical exam findings
rectal exam
stomach tube
abdominoscentesis
blood work
ultrasound
5
Q

what findings on a colic work up would indicate there may be a need for surgery?

A
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
6
Q

what HR is classed as tachycardia in horses?

A

> 60 bpm

7
Q

how much fluid on NG tubing is classed as abnormal / indicative of surgical colic?

A

more than 5L net

8
Q

what is the likely cost of colic surgery?

A

around 4-8k

9
Q

what sort of colic cases often result in high bills?

A

those that are unsucessful

10
Q

what may be required up front to secure colic surgery?

A

substantial payment

11
Q

what issues around transport are there associated with colic surgery?

A

where will the surgery be done and how will the horse get there

12
Q

what is the prognosis for surgical colic cases?

A

hard to tell pre surgery

duration of signs and severity of systemic disturbance will give clues

13
Q

what may aid in telling the prognosis of colic surgery cases?

A

duration of signs

severity of systemic disturbance

14
Q

are complications following colic surgery common?

A

yes - owners should be made aware from the outset

15
Q

what is key about preparation of a horse for colic surgery?

A

time is critical as it is an emergency so swift and efficient preparation is important

16
Q

what is involved in the preparation of the horse for colic surgery?

A
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
17
Q

what is the role of a jugular IV catheter?

A

administration of medication
IVFT
anaesthetic induction

18
Q

what size IV catheter is used for an adult horse?

A

usually 14G

19
Q

why should horses have their stomach decompressed prior to colic surgery?

A

cannot vomit and so refluxing will prevent gastric rupture of the stomach by decompressing

20
Q

what may cause horses to reflux fluid on passage of an NG tube?

A

if there is obstruction or ileus of the SI

21
Q

what does presence of reflux do?

A

helps diagnosis

22
Q

when should horses stomachs be decompressed?

A

prior to anaesthesia induction

23
Q

how will horse be restrained for passage of an NG tube?

A

stocks
twitch
sedation (Xylazine)

24
Q

where is the NG tube passed through in the nose?

A

ventral meatus to avoid ethmoidial turbinates

25
Q

why should the horses head be flexed when placing an NG tube?

A

allow passage of the tube into the oesophagus rather than the trachea

26
Q

what will the horse do as an NG tube is advanced into the oesophagus?

A

swallow

27
Q

how can correct placement of NG tube in the oesophagus be confirmed?

A

observe the left hand side of the neck for end of tube advancing in oesophagus to confirm correct placement

28
Q

what should be done if spontaneous reflux doesn’t occur when an NG tube is passed?

A

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

29
Q

why is IV fluid therapy needed when preparing a horse for colic surgery?

A

stabilise cardiovascular system and support circulation

30
Q

when can the abdomen be clipped?

A

may be started before induction or left until horse is anaesthetised

31
Q

what is the risk associated with clipping the abdomen before horses and anaesthetised?

A

may be safety issue if horse is painful and actively colicking

32
Q

why do horses shoes need to be removed and their feet taped before surgery?

A

avoid trauma and damage to the recovery box

33
Q

what must be done with the horses mouth before induction?

A

washed out to prevent debris being pushed into trachea at intubation

34
Q

what must happen after induction when preparing a horse for a laparotomy?

A
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
35
Q

what position are horses usually placed in for exploratory laparotomy?

A

dorsal recumbancy

36
Q

what must happen as well as placing a urinary catheter in male horses?

A

suture prepuce

37
Q

what incision is made for an exploratory laparotomy?

A

ventral midline

38
Q

what surgical kit is needed for colic?

A

check kit list

surgeons will have differing preferences

39
Q

what are the main steps involved in surgical treatment of colic?

A
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
40
Q

what are the main types of intestinal obstruction?

A

simple
functional
strangulating

41
Q

describe simple intestinal obstruction

A

lumen only obstructed

vasculature ok so intestine is minimally compromised

42
Q

what is the prognosis of simple intestinal obstruction?

A

good

43
Q

what is an example of a simple intestinal obstruction?

A

pelvic flexure impaction

44
Q

what causes a functional intestinal obstruction?

A

failure of peristalsis (e.g. ileus) leading to distention

45
Q

what can cause functional intestinal obstruction?

A

grass sickness

post op complication of ileus secondary to distention

46
Q

what happens during a strangulating intestinal obstruction?

A

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

47
Q

what can cause strangulating intestinal obstruction?

A

pedunculated lipoma

large colon volvulus

48
Q

what causes endotoxaemia in strangulating intestinal obstruction?

A

release of endotoxins into the circulation and peritoneal cavity due to oedema of intestinal wall that leads to increase in mucosa permeability

49
Q

what results from endotoxaemia?

A

systemic compromise and shock

50
Q

what is the prognosis of strangulating intestinal obstruction?

A

increasingly poor after 6-8 hours

51
Q

what secondary problems may occur from strangulating intestinal obstruction?

A

laminitis

52
Q

what does strangulating intestine look like?

A

goes from maroon to purple and then black as blood supply is compromised

53
Q

what is the effect of SI strangulating obstructions on more proximal structures?

A

effect of a simple obstruction with distention as gas and fluid cannot pass the obstruction

54
Q

what can be the result of prolonged distention of SI?

A

ileus

55
Q

what will the intestine be like distal to strangulating obstruction?

A

appear relatively normal

56
Q

what are the specific conditions that may lead to SI strangulating obstructions?

A

pedunculated lipomas
herniation (epiploic foramen, inguinal, mesenteric defects)
intussusceptions

57
Q

how is an SI resection performed?

A

isolate affected (devitalised) segment with bowel clamps at either end
ligate blood vessels supplying the affected segmant
resect

58
Q

what materials are used for anastomosis of the small intestine?

A

sutures or staples

59
Q

what must be closed to prevent SI herniation once surgery is over?

A

defect in mysentery that comes from the SI resection

60
Q

what must be checked about the SI and mysentery anastomosis?

A

patent lumen and integrity (no holes or leaks)

61
Q

once anastomosis has been performed and checked what should be done with the small intestine?

A

lavage and remove packing
decompress remaining bowel
replace in abdomen

62
Q

do simple or functional SI obstructions often require surgery?

A

no - can usually be managed medically

63
Q

how may simple / functional SI obstructions be managed surgically?

A

decompression of SI
possible enterotomy to remove obstruction
no resection or anastomosis required as non-strangulating so blood supply is not compromised

64
Q

what is the prognosis for SI simple obstruction?

A

good once resolved

65
Q

what are the risks associated with strangulating SI lesions involving resection or anastomosis?

A

contamination leading to peritonitis
endotoxic shock
ileus
post op adhesions

66
Q

what is the prognosis of survival to one year of strangulating SI obstruction treated with resection and anastomosis?

A

~50%

67
Q

what are the main causes of colic due to the large intestine?

A

displacement
large colon torsion
enteroliths (uncommon in UK)

68
Q

what are the common LI displacements?

A

left dorsal
nephrosplenic ligament
right dorsal

69
Q

what is the most common reason for LI colic?

A

displacement

70
Q

what happens during colonic displacement?

A

colon becomes distended with gas or fluid due to continued fermentation in the presence of obstruction
becomes displaced from normal anatomical position

71
Q

what is involved in the surgical management of colonic displacement?

A

recognise nature of displacement
decompression of distended bowel with needle
correction of displacement

72
Q

what may be necessary if colonic distention is due to fluid or food?

A

evacuation of the colon via a pelvic flexure enterotomy

73
Q

are colonic resections often performed?

A

no - technically challenging and rarely necessary

74
Q

what is colopexy?

A

anchoring of colon to body wall with sutures

75
Q

when may colopexy be performed?

A

non-athletes to prevent recurrence of displacement

76
Q

what is the most critical problem affecting the horses large colon?

A

large colon volvulus

77
Q

why is large colon volvulus the most critical problem affecting the horses large colon?

A

is commonly a strangulating obstruction with ischemia of a huge section of the horses GI tract

78
Q

where may volvulus of the large intestine occur?

A

sternal flexure or close to the attachment of the right ventral colon to the caecum

79
Q

what is the result of large colon volvulus?

A

great deal of gas distention within affected colon

80
Q

what is the cause of large colon volvulus?

A

unknown

81
Q

what animals are usually affected by large colon volvulus?

A

larger horses

brood mares around 90 days post foaling

82
Q

what is the onset of colic like in patients with large colon volvulus?

A

sudden and high degree of pain

83
Q

describe the colon on rectal exam of patient with large colon volvulus

A

enlarged and very evident

84
Q

is abdominal distention seen with large colon volvulus patients?

A

yes - often marked

85
Q

why is there often high HR and poor peripheral perfusion in patients with large colon volvulus?

A

mucosal ischemia leading to endotoxaemia and rapid deterioration of systemic status

86
Q

what is needed to correct large colon volvulus?

A

surgery to correct issue with removal of ischemic colon if necessary

87
Q

what is the prognosis of large colon volvulus linked to?

A

directly related to the time that elapses between onset of condition and surgery

88
Q

why are survival rates of large colon volvulus so much higher veterinary facilities near brood mare farms?

A

due to reduced transport time which means prognosis is much improved

89
Q

what is involved in the post-op care of abdominal surgery patients?

A
clinical exam and colic check every 2 hours initially then every 4
analgesia
antimicrobials
IVFT
belly bandage
monitor for complications
regular blood sampling for PCV, TP and lactate
NG tubing as needed
90
Q

how often do colic cases need a full clinical exam?

A

every 2 hours initially increasing to every 4 when stable

91
Q

what are the main post-op complications of colic surgery?

A
endotoxaemia
ileus
jugular thrombophlebitis
incisional infection
further obstruction
anastomosis leakage
peritonitis
adhesions
92
Q

when is endotoxaemia especially seen?

A

post strangulating obstructions

93
Q

what can endotoxaemia lead to?

A

SIRS

laminitis

94
Q

when is ileus often seen in post op colic cases?

A

prolonged SI distention and/or toxaemia

95
Q

what must be monitored during the post op period?

A
pain
pyrexia
GI system
CVS
incision
catheter
feet
respiratory system
96
Q

what should be monitored in the post op period with regards to pain?

A

behavioural signs of colic
heart rate
specific signs (peritoneal, incisional, MSK)

97
Q

how can pyrexia be monitored in the post op period?

A

rectal temp

98
Q

how can the GI system be monitored in the post op period?

A

reflux through NG tube will show blockage
faecal output
gut sounds
appetite

99
Q

how can the CVS be monitored in the post op period?

A

HR
MM
CRT
PCV, TP, lactate and electrolytes

100
Q

what should you look for when monitoring the incision in a post op colic case?

A

swelling (some oedema normal, excessive is bad)
pain
discharge

101
Q

what should you look for when monitoring the IV catheter?

A

swelling
pain
jugular patancy

102
Q

what should you look for when monitoring the feet in a post op colic case?

A

signs of laminitis due to endotoxaemia
movement around box
increased or bounding digital pulses
heat

103
Q

what should you look for when monitoring the respiratory system in a post op colic case?

A
auscultation
increased RR
nasal discharge or cough
effects of GA if any
aspiration pneumonia
104
Q

what should be done if there is still significant net reflux on passing a NG tube post op?

A

nil by mouth
IVFT
muzzle to prevent horse eating bedding

105
Q

what can the horse be given orally when reflux has ceased and parameters are improving?

A

small volumes of water that are gradually increased

106
Q

what depth of water in a bucket should be given if reflux in the horse has stopped and systemic parameters have improved?

A

5 cm depth

107
Q

what is the best first solid food for horses following colic surgery?

A

grass - hand grazing or picked

108
Q

what may be fed first following colic surgery if grass isn’t available?

A

small wet mashes of concentrates although less appetising

109
Q

when is hay introduced to the colic patient post op?

A

once mash or grass has been well tolerated small handfuls can be introduced and then gradually increased

110
Q

over how may days should it takes horses to return to normal volumes of food or hay once eating after colic surgery?

A

3 days

111
Q

what exercise should be allowed following colic surgery?

A

box rest for 6 weeks with very short walks in hand to allow grazing and promote gut motility (if temperament allows)

112
Q

what criteria must be met before a horse can be turned out into a small paddock?

A

check there are no incisional problems (e.g. breakdown of underlying abdominal wall closure) that may require more prolonged restriction of exercise

113
Q

how many weeks post op can horses be turned out into a small paddock?

A

6 weeks

114
Q

when can ridden exercise resume following colic surgery?

A

at 3 months if abdominal repair is sound

115
Q

what are the potential complications of colic surgery that are seen immediately?

A

endotoxaemia

ileus

116
Q

when is endotoxaemia most often seen?

A

post strangulating obstructions

117
Q

what are the signs of endotoxaemia?

A
tachycardia
tachypnoea
pyrexia and then hypothermia
hyperaemic MM that become purple and then brown
colic signs
dullness
118
Q

how is endotoxaemia treated?

A

IVFT

Flunixin, Polymixin B and Hyperimmune plasma (anti-endotoxic drugs)

119
Q

when is ileus most often seen as a complication?

A

prolonged SI distention and/or endotoxaemia

120
Q

how is ileus treated?

A

NG intubation to decompress stomach
IVFT
electrolytes if needed
prokinetics

121
Q

what fluids are needed in a patient with ileus?

A

maintenance (2ml/kg/hr)
correction of any dehydration
any losses

122
Q

what volume of reflux losses should be replaced through IVFT in the horse?

A

80% of volume refluxed

123
Q

how often should patients hydration status be assessed post op?

A

2-4 hourly

124
Q

what prokinetics may be used in a horse with pot-op ileus?

A

lidocaine infusion

Erythromycin and Metaclopramide (off licence)

125
Q

what are the potential short term complications of colic surgery in horses?

A
laminitis
jugular thrombophlebitis
peritonitis
colitis
incisional infection
126
Q

what is laminitis often secondary to post colic?

A

endotoxaemia

127
Q

how may laminitis be prevented in at risk horses?

A

ice boots

128
Q

what are the main signs of laminitis?

A

bounding (increased) digital pulses
heat
foot pain

129
Q

how is laminitis treated?

A

frog support
deep bedding
analgesia

130
Q

how is jugular thrombophlebitis treated?

A

remove catheter
local anti-inflammatory drugs
thrombolytic such as asprin
antibiotics if infection suspected or known

131
Q

if a horse develops jugular thrombophlebitis where should the new IV catheter be placed?

A

not into other jugular - other site if venous access still needed

132
Q

why should a new IV catheter not be placed in the other jugular vein if there is jugular thrombophlebitis?

A

to prevent bilateral blockage / damamge

133
Q

what are the main signs of peritonitis in horses?

A

colic
inappetance
pyrexia

134
Q

how is peritonitis treated in horses?

A

broad spectrum antibiotics

abdominal drainage and / or lavage in some cases

135
Q

what are the signs of colitis?

A

pyrexia
colic
diarrhoea

136
Q

when is colitis often seen post op?

A

after colon torsion / displacement where colon wall has been compromised
from antibiotic and NSAID use
sudden change in management

137
Q

how is colitis treated?

A

intensive nursing
IVFT
analgesia (avoid NSAIDs)
probiotics

138
Q

what drugs may help with colitis?

A

Misoprostal (prostaglandin analogue) and sucralfate

probiotics

139
Q

in how many laparotomy cases does incisional infection occur?

A

10-15% of cases

140
Q

when is incisional infection more common?

A

after second laparotomy

141
Q

what are the signs of incisional infection?

A

oedema around incision (large, some local is normal)
pain
drainage of purulent material

142
Q

how should incisional infection be treated?

A

antibiotics if horse systemically affected (e.g. pyrexia) - culture and sensitivity
encourage drainage

143
Q

how long will incisional infection persist for if present?

A

until suture material resorbs (~6 weeks)

144
Q

what are the the potential long term complications of colic surgery?

A

adhesions

145
Q

what are adhesions?

A

fibrin forming on intestinal surface with adheres to other areas of intestine

146
Q

what are adhesions a consequence of?

A

surgery and general handling of intestines

147
Q

what can adhesions result in?

A

further obstruction and colic

148
Q

what does recurrent significant colic due to adhesions often result in?

A

euthanasia as owners are reluctant for horse to have surgery when the prognosis would be guarded at best

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