Module 14 Wk 4 Flashcards
How does Equine post-ana myopathy present clinically?
One or more muscle groups being effected, swollen, pain and hot to touch.
Why does EPAM occur?
- Failure of perfusion/oxygen delivery to muscles
- Hypotension ↑ risk
- Hypoxaemia ↑ risk
- Long anaesthesia ↑ risk
- Heavier horses ↑risk
- Positioning
- Compression of blood vessels
- Stretch occlusion
How can we prevent EPAM?
- Minimise duration of anaesthesia
- Position and pad well
- Maintain oxygen delivery to muscles
How can we treat EPAM?
- Analgesia
- Copious Intravenous crystalloids
- Acepromazine? Oxygen free radical scavengers?
How should you position a horse during anaesthesia?
- Distribute weight evenly through muscle bellies as can be seen pulling the lower limb forwards.
- Keep limbs supported in as neutral a position as possible to prevent damage by overstretching
- And Pad well to prevent compression injury.
What are genetic muscular diseases?
- Equine polysaccharide storage myopathy (EPSM)
- HYPP – Hyperkalaemic Periodic Paralysis
- MH - Malignant Hyperthermia
What horses is spinal cord myelomalacia more common in?
Young, male horses more common
what kind of musculoskeletal traumas can occur during ana in horses?
Fractures - Limbs, cervical spine, skull
Disarticulation - Fetlock, tail
Whats the difference between stridor and stretor?
Stridor (inspiratory) – high pitched noise
Stertor (expiratory) – heavy snoring sound
What are the causes of airway obstruction in equines during anasthesia?
- Nose in the corner of box
- Nasal congestion
- Laryngeal paralysis
- Airway swelling
T/F nasal congestion is more common in longer anaesthesia.
True
What should you do if there is nasal congestion during an equine anaesthesia?
Elevate the head, and place the nasopharyngeal tube.
What factors play into post-anaesthetic colic?
- Stress
- Transport
- Anaesthetics/analgesics
- Surgery
- Feeding (or lack of) - Before AND after anaesthetic
What are IV cannulas complications that can occur with equine anaesthesia?
- Infections
- Thrombophlebitis
- Kink/obstruct
- cap can come off in recovery
Why is thrombophlebitis be a problem?
Can lead to jugular obstruction
Describe equine assisted ana recovery technique
- combined with post-op sedation
- topical phenylephrine or nasal tube placed
- soft tight-fitting head collar placed and tail plaited
- O2 supplementation
- ET tube removed
- eyes covered
how long after equine anaesthesia should you with hold food for?
3-4 hours
(equine wound)
what is the sequence of wound healing?
- Inflammatory
- Debridement
- Repair (proliferative)
- Maturation phases (remodelling)
When does the inflammatory stage occur?
First 2-3days
What happens during the inflammatory stage of wound healing?
White blood cells move into the wound, neutrophils appear first and then die releasing enzymes that attack cellular debris.
T/F neutrophils appear faster in ponies than horses?
True
When does the debridement phase occur?
6-8 hours after
What does the duration of the debridement phase depend on?
The amount of debris and contamination.
What happens during the debridement phase of equine wound healing?
Monocytes become macrophages which are responsible for the removal of debris.
What is the repair phase of wound healing?
Strength increases rapidly. Fibroblasts appear in 3 days when they lay down collagen and other CT. Capillaries also appear and granulation tissue forms.
When does the maturation phase of wound healing occur?
2 weeks and continues for 6-12months.
What happens during maturation phase of wound healing?
Granulation tissue and collagen production decline. Intra and intermolecular cross-linking of collagen fibres occur.
What are 12 recognisable factors that may inhibit healing of a wound?
- Infection
- Foreign body
- Necrotic tissue
- Movement
- Loss of blood supply
- Poor tissue oxygenation
- Tissue deficit
- Continued trauma
- Local factors
- Health status
- Tumour transformation
- Iatrogenic factors
T/F a skin wound in the horse should not cause lameness?
True - Skin wounds are not very painful and should not cause much lameness, if the horse is very lame, it is very likely there is damage to some underlying structure or infection within a tendon sheath or joint.
What is a primary wound closure suitable for?
- Surgical wounds and injuries which are not grossly contaminated, infected or swollen
- Wounds without excessive tension or soft tissue devitalisation
- Nothing gained by attempting primary closure if you feel that breakdown is likely
What are the preferred suture materials for skin sutures?
Monofilament nylon and polypropylene
What is the criteria for primary closure?
- Must be vascular
- Must have minimal tension
- Must be clean
- Must be within golden period (i.e., not infected)
Why might delay wound closure?
- Severe contamination
- Contusion or devitalised tissues
- Swelling
- Infection
What is healing by second intention?
Inflammation-> formation of granulation tissue-> wound contraction-> epithelialisation
What is the most appropriate agent to lavage a wound?
Saline
T/F For every hour sooner that you wash a wound, you will half the risk of infection
Trueeee
What are the principles of infection control that you should apply to equine wound?
- Removal of foreign material and debris
- Removal of devitalised tissue
- Eliminating micro-organisms to below critical level required to maintain septic process
- Removal destructive radicals & enzymes
- Improve action of antibiotics
- Restore pH to physiological levels
- Remove purulent exudate
T/F Total lack of movement can result in a weak scar because some stress is required to induce proper arrangement of collagen
True pookie
How can you immobilise a wound?
Casts, splints, & Robert Jones bandages
Why would you use a cast to immobilise a wound?
To eliminate movement, Compress and protect a wound.
Should you remove flaps off a wound?
No, unless you are confident they are devitalised
How might you relieve tension in a wound?
- tension relieving sutures
- stent bandages
- drains
- reliving incisions
What is sequestrum formation?
Where a section of bone dies and becomes a foreign body
What should you always check when a horse has a wound?
TETNUSSSSSSS
T/F the horse has a propensity to develop granulation tissue earlier in healing and in excessive amounts?
True
Why is granulation tissue in an open would beneficial?
- Migration of epithelial cells
- Resistance to infection (inherent resistance to bacterial colonisation)
- Process of contraction centered around its development
What factors encourage exuberant granulation tissue
- Moisture
- Warmth (low temperature decreases metabolic activity)
- Low oxygen tension
- Low ph
- Irritation
- Infection
- Motion
How can you control and treat granulation tissue on a wound?
- Counter pressure (bandages/casts)
- Immobilisation
- Surgical excision
- Infection control
- Topical agents?
- Cryosurgery
- Biological dressings
- Skin grafting
What dressings provide moisture?
hydrogels and hydrocolloids
What dressings provide absorption?
foam, allevyn, alginate seaweed derived, polyacrylate, padding and wadding, hydrofibre
What dressings donate something to the wound?
antimicrobial killing ability given to the wound ie honey
(SA wound healing)
what do we need to provide optimal wound healing?
- Good blood supply
- Moist wound surface
- No surface trauma
- Infection controlled
- Non viable tissue and foreign material removed from the wound
What are the different types of wounds?
- Clean
- Clean contaminated
- Contaminated
- Dirty
What is primary closure of a wound?
- Immediate closure of healthy viable tissue without tension
- Clean or some clean contaminated wounds
- Surgical wound, some traumatic wounds
what is a delayed primary closure of a wound?
Where you close before granulation tissue starts but after bacteria and foreign material has been removed
What is secondary closure of a wound?
This is where the closure happens after the granulation bed has been formed.
What is the process of secondary intention?
- Granulation
- epithelialization
- Contraction
How would you assess the wound in consultation?
- Is it contaminated?
- What degree of tissue trauma is there?
- Can you close this wound Immediately, After some management or Never?
- What is the prognosis and likelihood of it healing?
- What is the cost? (both financial and welfare to the patient)
How can you do surgical debridement?
- Remove devitalised or contaminated tissue
- Use sharp dissection with a scalpel.
- Scrape with blade
- Rub with dry swab
- Removal of redundant tissue speeds up the inflammatory phase
How do you do non-surgical debridement?
- Used to remove debris that cannot be removed by lavage or surgical debridement
- Uses dressings to debride the wound, effective but causes injury to normal tissues also - Wet to dry dressings
What are the three layers in dressings and what do they do?
- Primary or contact layer - This controls the wound environment
- Secondary layer - Absorbs excess fluid, holds primary layer in place and provides structure to bandage
- Tertiary layer - Outer layer secures the dressing in place and protects the secondary layer
How does the contact layer of a dressing control the wound enviroment?
- Debrides infected or necrotic tissue
- Absorbs exudate
- Protects the wound
- Promotes wound healing
- Provides analgesia
- Can be adherent or non adherant
T/F at dressing changes for a wet to dry dressing you dont need to do it under GA?
False - At dressing change the dressing is not moistened and removed. This debrides the wound but will also cause trauma so is painful!!
When should you change a wet to dry dressing to a non-adherent one?
When all necrotic tissue is removed, the amount of exudate is reduced and granulation tissue starts to form.
What is the aim of a non-adherent dressing?
To promote granulation and epithelialisation of the wound
What are foam dressings purpose?
They are absorbants that have semi-permeable membranes to allow Oxygen exchange and controlled evaporation - keeps the wound moist, not wet.
What do hydrogels encourage?
Encourages natural debridement and sloughing
What does healthy granulation tissue look like?
Red, uniform and flat, progressing daily with minimal exudate
what is the purpose of the secondary layer of a bandage?
- Holds contact layer in place
- Absorbs and exudate that passes through contact layer
- Supports and protects the wound and provides padding
What are examples of secondary layers of bandaging?
Examples – soffban, cotton wool, conforming gauze bandage
What is the purpose of the tertiary layer in a bandage?
- Holds the intermediate layer in place
- Protects the other layers from trauma and contamination from the environment and the animal.
What is an example of a tertiary layer of a bandage?
coflex
What are 2 examples of topical wound treatment?
- silver dressing
- manuka honey
(ruminant ana)
What should preparation look like for ruminant anaesthesia
Starvation and water deprivation (calves F-8-12hr W-8hr) (adult cattle F-24hrs W-12hr) (Large mature bull F-24-36hr W-24hr)
Why must you place a long catheter in ruminants?
Skin much thicker and looser at the neck so moves alot
In cattle what is the dose rate IV for Xylazine pre med?
0.02-0.1mg kg-1
In cattle what is the dose rate IM for Xylazine pre med?
0.1-0.2 mg kg -1
In cattle what is the dose rate IV or IM for Detomidine pre med?
10 – 40 µg kg -1
What may happen in small ruminants when a2 administered?
Hypoxaemia and pulmonary oedema
What is the common adult bivine ana protocol?
Premedication
- Xylazine 0.2 mg kg -1 IM or 0.02 mg/kg IV
- Butorphanol 0.2 mg/kg IM/IV
Induction
- Ketamine 3 mg kg -1 IV ± thiopentone 1-2 mg kg -1
Why do you have to be careful with the use of thiopentone in cattle?
It increased the risk of regurgitation?
What is a common IM induction protocol for a small ruminant?
Detomidine 0.02 mg kg -1 + ketamine 15 mg kg -1 (Mixed in the same syringe)
What is a common IV induction protocol for a small ruminant?
- Detomidine 0.01-0.02 mg kg -1 + butorphanol 0.2 mg kg -1 IM/IV
- Ketamine 2-5 mg kg -1 IV
What is the only opioid licenced for use in the UK for cattle?
Butorphanol
How can you encourage regurgitation material to stay in the rumen when intubating a calve or small ruminant?
Keep in sternal position with head up
What are common problems with ruminant anaesthesia?
(Porcine Anaesthesia)
What might be an issue with pigs temperament?
- Aggression
- Very noisy
- Bite
how lonhs should a pig fast for before GA?
8-12hrs and 24hrs for abdominal surgery
Why is IM behind the ears an effective location for sedation in porcine?
It avoids valuable meat-producing hams, and there is less fat, so it actually goes into muscle.
What are your 2 options for pre-med in porcine for meat?
Option 1
Azaperone 2 mg kg -1 + Ketamine 2 - 5 mg kg -1 IM
Option 2
Detomidine 0.1 mg kg -1 + Butorphanol 0.2 mg kg -1 + Ketamine 5 mg kg -1 IM
What are your other 3 options that you can use in research pigs not intended for meat production?
Option 3
(non-aggressive pigs used to handling) = Midazolam 0.2 mg kg -1 IM
Option 4
Midazolam 0.2 mg kg -1 + Ketamine 5 mg kg -1 IM
Option 5
α2 agonist or benzodiazepine + opioid of choice + alfaxalone IM
What can you use to induce ana in meat producing pigs?
Ket 2mg/kg IV +/- thiopentone IV
What should you use to help you intubate pigs?
A guide to help aid where to insert, twist the ET tube twice - on entering larynx and again when you get to the trachea
