Equine iatrogenic emergencies Flashcards
Define iatrogenic
Relating to illness caused by medical (veterinary) examination or treatment
Name some examples of iatrogenic issues
- Nasal haemorrhage during nasogastric intubation / endoscopy
- Rectal tears during rectal examination
- Evisceration following castration
- Adverse drug reaction
- Anaesthetic death
Describe the legal issues and client management of iatrogenic issues
- There are often recognised risks associated with particular procedures
- Can be stressful and upsetting for both owner and vet
- Rarely associated with negligence
- Owners may question the veterinary surgeons actions
- Failure to identify and deal with these may lead to a negligence claim
Name the 3 major complications that can occur due to nasogastric intubation
Haemorrhage
Oesophageal perforation
Inhalational pneumonia
Describe haemorrhage as a consequence of nasogastric intubation
- Can be alarming to the owner
- Mention possible complication
- Leave the horse quietly for 5-10 minutes
- Haemorrhage will usually stop by this time
- Do not pack the nasal passages
What are some key tips to avoid nasogastric intubation problems
Use an appropriate tube
Ensure the horse is restrained
Pass the tube along the ventral meatus
Never force the tube
Ensure it is placed in the oesophagus/stomach before administering fluids
If haemorrhage continues following nasogastric intubation what should be done?
Endoscopy
Clotting profiles
Describe oesophageal perforation as a consequence of nasogastric intubation
- Uncommon
- Excessive force
- Secondary to existing problem
- Suspect if blood on nasogastric tube (in the absence of epistaxis)
How is oesophageal perforation further assessed and treated?
Endoscopic assessment of the oesophagus +/- radiography
Full thickness perforations have poor prognosis
How does inhalation pneumonia occur?
Inadvertent passage of nasogastric tube into trachea
Always check positioning of the tube
How can you try and prevent rectal tears during a rectal examination?
- Be in a safe position
- Ensure the horse is restrained
- Sedate if necessary +/- butylscopolamine
- Never push against the rectum if the horse strains
When is the risk of rectal tears increased?
Arabians
Stallions / colts
Colics
Fractious horses
Using an ultrasound probe
Describe the initial action steps when a rectal tear has occured
- Inform the owner
- Sedation
- Butylscopolamine
- +/- epidural anaesthesia
- Evaluate rectal mucosa: Lubrication and lidocaine
- Proctoscopy
- Determine the location and grade
Describe the grades of rectal tears
1 = mucosa and submucosa
2 = muscularis only
3a = mucosa and muscularis (serosa intact)
3b = mucosa and muscularis (tear into mesocolon)
4 = All layers
How are rectal tears managed, based on their grade?
Grade 1 and 2 - Medical management
Grades 3 & 4 - Medical / surgical management / euthanasia
List some other Iatrogenic Injuries/Accidents
Adverse drug reaction
Anaphylaxis
Intracarotid drug administration
Perivascular injections
Injection site abscess
Iatrogenic synovial sepsis
Broken needles
Catheter accidents
Anaesthetic-related complications
List the golden rules when dealing with trapped/stuck horses
- Trapped horses can be unpredictable: Offering food and keeping a companion nearby may help
- Be aware of your own and others’ safety: Work from the spine side of the horse if they are lying down
- Have control of the horse’s head: Place a headcollar
- Be prepared to sedate / anaesthetise
- Never release the horse unless it has somewhere safe to go
- Always plan an exit route for you and others
Describe how to deal with the emergency services in the case of a trapped/stuck horse
- You may be required to sedate / anaesthetise / euthanase
- Ensure you are properly attired
- Identify yourself to the person in charge
- Discuss the plan – human life takes priority. Horse may be asked to be euthanised
- Some emergency service professionals may not be used to horses
How should a horse be assessed once released
Assessment & treatment of:
- Limb fractures
- Wounds
- Head / ocular injuries
- Dehydration / hypothermia
- Acute haemorrhage
- URT / LRT inflammation
Which injuries are most likely to occur due to stable fires?
Smoke inhalation – scope?
Skin burns
Corneal ulceration
Hypovolaemia = ‘burn shock’ - Need IV fluids
How should horses involved in stable fires be initially assessed?
Lukewarm water; remove rugs
Sedation / anxiolytics if required
Administer flunixin
+/- oxygen
IV catheter +/- tracheostomy
Referral / euthanasia may be needed
How are burns assessed/classified?
- Extent of burns (rule of 9’s) = Percentage of total body surface area (TBSA)
- Depth of burns (superficial layers of skin through to involvement of bone, fascia etc.) = 1st – 4th degree
- Extent of hypovolaemia
How should less severe burns be managed?
Cool skin
Clip hair
Lavage (0.05% chlorhexidine solution – very dilute)
Water (not oil) based antimicrobial ointment: Silver sulfadiazine
What advice should be given to owners when they have a horse with a wound?
- Control haemorrhage: Dressing, Pressure
- Do not move the horse if it is very lame unless in imminent danger
- Minor wounds in low-risk areas: telephone advice may be all that is needed
- More severe cases: tell owners not to apply anything to the wound
What first aid may be administered to wounds?
Haemorrhage – very sturdy bandage. Wounds may bleed for several hours so need to wait for this to stop before it can be evaluated
Limb stabilisation
What history is imperative to obtain when presented with a horse with a wound?
Does it have tetanus cover?
Describe the clinical exam of a horse with a wound
Shock/ other injuries
Assess stance / weightbearing
Vital parameters - Be aware that PCV and Total protein don’t change very quickly when a horse has lost blood – can take 12/24hrs
Which parameter can be used instead of PCV and total protein to assess blood loss?
Lactate will increase faster so can use this parameter to gather information about blood loss
How can a detailed assessment of wounds be carried out
+/- sedation
- Assess: Age of wound, Contamination, Location (remember anatomy!) – what structures have been affected?
- Apply sterile gel to the wound – stops hair going into the wound
- Clip and clean the site around it
- Lavage
- Sterile gloves, use finger / sterile probe: Depth and direction, Foreign material, Subcutaneous pockets, Bone / tendon exposure
How can wounds be further assessed?
Radiography / ultrasonography
What factors should be considered when treating wounds
Time since injury
Contamination / infection
Tissue defects
Tissue flaps / viability
Patient compliance
Is GA needed
Which wounds are ideal for suturing?
<8h old - If longer than this you need to warn the owner that the wound is more likely to break down
Healthy tissue
Eyelids, nostrils, lips (full thickness)
How can horses be restricted for treating wounds?
Twitch / sedation
Describe local anaesthesia use in horses with wounds
Mepivacaine / lidocaine (not with adrenaline)
Regional nerve block
Ring- / L-block
How are wounds treated/stitched up?
- Remove necrotic / non-viable tissue
- Skin staples: Quick & easy, Tissue cannot be under tension
- Suturing: Equine skin: 3 - 3.5 metric (2-0 – 0 USP) monofilament e.g. polypropylene. Subcutaneous 3 metric (2-0 USP), absorbable e.g. poliglecaprone
+/- Stenting to remove tension on sutures
+/- drain
+/- dressing and bandaging
Describe ongoing management of horses with wounds
- Analgesia / anti-inflammatories
- Antimicrobials
+/- tetanus toxoid / tetanus booster
+/- box rest (beware colic) - Timing of suture / staple removal - Usually 10-14 days
- Dressing / bandage changes - Frequency depends on amount of exudation – ballpark every 2-3 days initially
Describe secondary intention healing for wounds
- Sterile hydrogel & non-adherent, absorbent dressing initially
- Various dressings / topical treatments for ongoing management
- Bandaging of the distal limb important (+/- splint or cast bandage)
- Ongoing wound management: Duration, Cost
List the possible complications of wounds
- Synovial sepsis / fracture (missed initially)
- Sequestrum formation
- Dehiscence: anything being sutured can always break down
- Foreign material remains in situ
- Bandage sores
Describe sequestrum formation
Where cortex of the bone exposed
Acts like a foreign body – leg will not heal/stop draining until that bit of bone is removed
Describe the types of skin grafting
Pedicle grafts
- Rarely used – inelastic skin
Free grafts
- Usually autografts
- Pinch / punch / tunnel grafts
- Solid or meshed sheets (full / split thickness)
- Meek micrografts
Describe the timing of skin grafting
Healthy granulating wound bed
Can also be applied to fresh injuries / surgically created defects
For a skin graft to be accepted the wound bed must have what requirements?
- Vascularised
- No necrotic tissue
- No overt infection
- No evidence of delayed wound healing: Sequestrum, Foreign body
List the indications for skin grafting
- Traumatic injuries
- Non- / slow-healing granulating wounds
- Adjunct to management of skin neoplasia
- Extensive skin burns
- Deformity-causing scarring
Describe preparation of the skin graft donor site
Neck
+/- abdomen
Clipped, local anaesthesia
Skin preparation
Describe placing skin grafts
- Start at the lowest site (prevents haemorrhage obscuring sites)
- Make a pocket in the granulation bed - No 15 scalpel blade
- Tuck grafts into each pocket
- Non-adhesive dressing, bandage
- Box rest
- Change bandage in 5-7 days
In which situations would advanced grafting be considered?
- Wound / surgically created defect cannot be closed
- Secondary intention healing would be prolonged & result in large scar
- More simple techniques would not provide sufficient cosmetic / functional result
- Defect too large for more simple techniques
Describe full thickness grafting
GA / sedation and local anaesthesia
Pectoral region most commonly used (sutured closed)
Insufficient skin to cover a large defect
Describe split thickness grafting
Can be taken from several sites (ventral thorax / abdomen)
Larger defects can be covered
More specialist equipment and expertise needed
