ECP 4 Flashcards
(100 cards)
1
Q
What are the 6 main special physiological considerations for equine anaesthesia
A
1) large muscle mass
2) myopathy on recovery
3) Hyperkalemic periodic paralysis
4) Respiratory concerns
5) additional respiratory concerns
6) effect of GI tract in dorsal recumbency
2
Q
In terms of large muscle mass for horses how does this affect equine anaesthesia and the two main forms of issues
A
- Risk for neuropathy ○ Must provide adequate padding ○ Special attention to surface nerves (i.e. Facial) 1) Facial nerve paralysis 2) radial nerve paralysis
3
Q
Facial nerve paralysis in equine anaesthesia what due to, how to avoid and does it resolve
A
○ Often due to pressure on nerve from halter in lateral recumbency
§ Remove halter for procedure
§ Avoid halters with metal buckles on dependent side during recovery
□ Place a towel or pad between the buckle and the face if unavoidable
○ Can resolve spontaneously over a few days but not always
§ Affect ability to eat and drink
4
Q
Radial nerve paralysis in equine anaesthesia what due to, how to avoid and does it resolve
A
○ Can be caused by prolonged lateral recumbency
§ Pull dependent limb forward -> unstacks the shoulders so brings body weight of the radial nerve
May resolve spontaneously over several days
5
Q
Myopathy on recovery in equine anaesthesia why occurs, how to prevent and the worse result
A
- Due to poor perfusion intraoperatively
○ Blood flow to both dependent & “up” limbs decreased @ 1.5 x MAC Isoflurane (AJVR 1987)
§ Other drugs can affect this too!
○ Maintain MAP = 70 mmHg (80 mmHg for heavily muscled breeds) - need to perfuse the butt of the horse - Can develop rhabdomyolysis (muscle death)
○ Supportive care + treatment for potential myoglobinuric renal failure - can be death sentence or reduced function
6
Q
Hyperkalemic Periodic Paralysis for equine anaesthesia what is it, caused by, how to prevent
A
○ genetic disorder of Quarter Horses
- Stress of sedation & anaesthesia can cause attack
- Quarter Horses: test for presence of gene in America and possibly do in Australia
○ Pre-treat both hetero- & homozygotes w/ acetazolamide (promote insulin production drive Na back into cells) prior to anaesthesia
- Careful intraoperative monitoring for signs of high K+ - for all standard breeds that haven’t tested
○ BRADYCARDIA first clinical sign
7
Q
What is an important respiratory concern with equine anaesthesia, why does this occur
A
- At risk of development of hypoxemia & hypercapnia w/out ventilatory support
General anaesthesia leads to V/Q mismatch in the horse!! (↑ shunt fraction)
Due to: - Horses preferentially perfuse dorsocaudal lung fields
- Positioning changes ventilatory patterns
○ Lateral recumbency causes atelectasis of dependent lungs = decreased ventilation
8
Q
What are the 2 other important respiratory concerns of equine anaesthesia why occur and how to prevent
A
1) Hypoventilation
§ Positional, weight of chest wall, muscle weakness from drugs, GI tract impeding diaphragmatic movement (fall onto diaphragm)
§ Assisted ventilation should be provided for procedures longer than 45-60 mins
2) Obligate nasal breathers
§ Nasal edema can occur (esp. in dorsal)
□ Consider nasotracheal tube &/or phenylephrine for recovery
§ Confirm nasal air flow after extubation
9
Q
Effect of GI tract in dorsal recumbency in equine anaesthesia what occurs and what can lead to
A
○ Stomach/intestines rarely fully emptied
○ Weight of on abdominal vena cava ↓ venous return & cardiac output
§ May see tachycardia to compensate
○ Will push on diaphragm → ↓ diaphragmatic excursion → Hypoventilation
10
Q
What are the 3 main special pharmacologic considerations with equine anaesthesia
A
- Anticholinergics:
Decrease GI motility = Ileus = Risk of Colic - Opioids:
○ Can cause excitement when given alone - not given alone
○ All opioids decrease equine GI motility!! - not first line of defence for pain
§ Butorphanol “theoretically” less so than pure mu’s - only lasts for an hour -> redosing issue - Alpha-2 Agonists: - use in sick horses
○ Provide visceral analgesia - significant pain relief
§ Better than opioids or NSAIDs
○ Xylazine = significant contributor to colic therapy
○ Other systemic effects (↓CO, etc.) as in other species
11
Q
What are the 2 main venous access in an adult horse, what needle and what used for
A
1) Jugular vein ○ 18-20 gauge needle for injections - can tell the difference between carotid (high blood flow) and jugular (trickle) ○ Most common vein accessed in horse ○ Carotid artery just dorsal to vein! 2) Cephalic Vein ○ Good for short term catheters ○ Some horses do not tolerate ○ Impractical for injections or blood draws 3) Others ○ Femoral, Lateral Thoracic
12
Q
What are the 4 main important equine patient preparation for anaesthesia
A
- Physical Exam
- Include respiratory & cardiac auscultation
- TPR, MM colour & CRT - Bloodwork
- PCV, TS (+/- Creatinine) every time
- Others as needed dictated by patient/procedure - Clean/Pick feet + wrap
- Remove shoes if possible - Wash out mouth!
13
Q
What are 2 main equipment needed for equine anaesthesia
A
1) Mouth gag ○ Typically PCV or metal dental gag - to stop the horse from chewing the tube (high jaw tone) 2) Choosing an Endotracheal Tube ○ 26-30 mm ID ○ 20 mL cuff syringe Test cuff!
14
Q
What is the goal of equine premedication, what combination of medications generally used
A
- Goal is moderate sedation
○ Usually an alpha-2 agonist +/- opioid
○ +/- acepromazine - not enough for pre-medication by itself BUT study suggest that will reduce risk of dying
§ Needs 30mins to work -> not used in emergency situation
§ Stallion -> risk of priapism -> consider positives and negatives
15
Q
What are the 4 main clinical signs of sedation in the horse
A
○ Dropped head
○ Droopy lower lip
○ Relaxed ears
○ Relaxed posture
16
Q
Equine anaesthesia induction what is the goal, most common combination of medication, what is important to consider and the 2 types
A
- Goal is controlled “fall” to recumbency
○ Diazepam/Ketamine (most common), Thiopental, Guaifenesin/Ketamine, Xylazine/Ketamine, Zolitel - Safety of personnel is priority!
Make sure everyone in area knows that horse has drugs “on board”
1) Field induction
2) Stall induction
17
Q
Stall induction for equine anaesthesia what are the 2 main types
A
1) Assisted induction
○ Horse against wall with personnel holding to wall - eases them down
- Safer to use “swing gate” to hold horse against wall if possible
2) Pneumatic Lift Table
○ Horse must be sedated prior to “strapping” to table
18
Q
Intubation of horses what are the 2 types how to intubate and when don’t you need to
A
1) Endotracheal intubation is “blind”
○ Place mouth gag between incisors
○ Slide tube through gag and slowly advance into trachea (feel like butter, oesophagus more tissue)
○ Confirm tracheal placement
§ EtCO2 ** - see carbon dioxide movement
§ “Feeling” air
§ Palpating neck
2) Nasotracheal intubation sometimes performed
○ Typically 20-22 mm ID
○ Technically more difficult
- Field Anaesthesia – horse may not be intubated
19
Q
Equine Anaesthesia maintenance what used for different length procedures
A
1) Balanced crystalloids @ 10 mL/kg/hr
2) TIVA Triple Drip - = 45 mins to 1 hr as need ventilation support for larger procedure
3) Maintain on inhalants - > 1 hr
○ Iso MAC – 1.3-1.4%
○ Sevo MAC – 2.3-2.8%
20
Q
Blood pressure monitoring during equine anaesthesia what are the 2 types and goal in terms of level
A
- Goal of MAP >/= 70 mmHg
○ 80 mmHg in heavily muscled breeds/drafts
1) Can use non-invasive
○ Doppler
○ Oscillometric
2) Invasive (arterial) is gold standard - common for surgery
○ Facial, Mandibular, Transverse Facial, Lateral Metatarsal aa.
21
Q
What are some options for intraoperative analgesia for equine anaesthesia
A
○ Intermittent opioid boluses ○ Local and regional anaesthetics ○ Intra-articular morphine ○ CRI’s § Lidocaine § Alpha-2 agonists § Butorphanol? § Ketamine
22
Q
Recovery from equine anaesthesia what are important considerations
A
- Place in lateral recumbency in quiet, dim stall
- Provide supplemental oxygen
- Extubate when breathing spontaneously and well
○ No need to wait for swallowing - no risk of regurgitation - Can be very eventful/rough
○ Consider assisted recovery
• Hand - not recommended for adults
• Rope - assistance
• Sling - to help protect limbs
• Pool - Consider light sedation while inhalant wears off
23
Q
Foal anaesthesia what to do with mare
A
○ Let her accompany the foal for as long as possible
○ She may need sedation
○ Let her see the foal as soon as possible afterwards - make sure can stand properly
24
Q
Foal anaesthesia what are 4 main considerations in terms of physiological differences
A
1) Immature Liver ○ May not maintain normoglycemia ○ Altered/slow drug metabolism 2) Immature thermogenesis ○ May need external heating support 3) More compliant chest and high RR 4) Immature SNS
25
Foal anaesthesia premedication examples
- Benzodiazepine (sedative in foals) + Butorphanol – great sedation/premedication for very young &/or sick foal
- Alpha 2 Agonist for older/robust foals
26
Foal anaesthesia induction protocols
- Facemask or NT tube Inhalant in oxygen
○ But CEPEF showed that injectable reduced mortality
- Propofol or Alfaxan (+/- muscle relaxant)
- Ket/Val (ketamine/diazepam) - in older animals
- KetoFol! -> ketamine and Propofol
Typical endotracheal tube sizes 8-16 mm ID - special foal ones
27
Foal anaesthesia what maintain on, monitoring and recovery
Maintain on Inhalants or TIVA
Monitoring important as with adults
- Direct ABP may be technically more difficult
- May need external heat support
- Should check perioperative blood glucose
Recovery usually assisted by hand (1-2 people depending on size/age)
28
Heat requirements for reptiles what are the two main types and the important instruments for this
Poikilothermic
- PBT: preferred body temperature varies for every body function
- POTZ: preferred optimal temperature zone varies between taxa/species
○ Tank need to provide this!!!!
- Heat source preferences vary between taxa
Thermostats vs thermometers
29
What are the 3 different light requirements for reptiles and what reptiles need what
○ UVA,B and C - A = activity, B = bone, C = cancer
○ UVA debate
○ UVB essential for chelonians, lizards other than geckos, crocodiles
§ Most snakes don't need it
30
Ultraviolet light for reptiles what are important considerations
- 30cm or less from basking area -> larger animal needs longer length globe
- Change globe every 6 months
- Full spectrum is visible UVA spectrum only
- Fluorescent, mercury vapor, compact UVB
- Blocked by glass and plastic
31
Humidity for reptiles what does it affect how to get high and low humidity and how do some reptiles access water
- Enclosure humidity affects hydration, hygiene, health of sin, lungs and gut and behaviours
○ Low humidity: small water bowl at cool end, rare bathing and misting, dry substrates, excellent drainage
○ High humidity: large shallow water source near heat, foliage, frequent misting, bathing allowed
§ Good ventilation essential for both
- Some reptiles drink from containers, other from foliage or misting
- Too much access to water can be as unhealthy as too little from some taxa
32
Space requirements for reptiles what are 3 important considerations
1) Enough space to stretch out, climb or swim and to behave normally
○ Spread out from one corner to the other diagonally
2) Enable retreat from companions
○ Give multiple hides, basking spots etc.
3) Designed to provide an appropriate temperature mosaic
33
What are some important considerations with substrates and furnishings
Substrates
- Consider hygiene, thermal properties, absorbency, abrasiveness
- Turf, newspaper, commercial litters, stones, slate tiles (can hold heat), bark, sand
Furnishings
- Logs, rocks, tiles, plants, artificial works
- Hides, burrows, screening
34
What are 4 important things that cause stress in reptiles in terms of the envionment
- Handling reptiles usually takes them out of their POTZ
- Socialising with mammalian carnivores is usually stressful
- Being under constant surveillance by us or other pets is very stressful
- Vibrations through their tanks also cause stress
35
What are general diets for snakes, chelonians, lizards and crocodiles and what is important to consider with diets
- Snakes: whole prey, never live prey
- Chelonians: tortoises are terrestrial and herbivores, turtles are aquatic, fresh water turtles eat invertebrates with varying proportions of plants
- Lizards: very wide range of dietary niche
- Crocodiles: carnivores
The quality of the diet is only as good as the quality of raising of the prey items
36
what are important aspects of hygiene in an aquatic tank and vivarium
```
Aquatic
- Water quality monitoring
○ Nitrogen cycle, water hardness, Ph
- Filtration
○ In tank vs external, under gravel
- Partial water changes
Vivarium
- Daily spot cleaning, 3-6 monthly scrub F10
- Mite prevention and treatment
```
37
What are the 3 important tank set up considerations when asking a client
- Poikilotherms with individual POTZs
○ Heat source management, basking opportunities, insulation, ventilation
- Light (visible and UVB)
○ UVB globe type, position, age of globe
○ Day length
- Humidity
Water source, misting, furnishings, ventilation
38
Rabbit physiological characteristics what makes them different
- Small lung volume
- Obligate nasal breathers
- Narrow gape in a crowded mouth
- Cannot regurgitate and must eat very often
○ Caecal fermenters -> gut status - DON'T FAST RABBITS
- Prey animal mask their fear and pain
39
Rabbit patient examination what are 5 important parts
- Patency of nasal passages
- Hydration
- Gut fill and faecal consistency
- IV catheterisation marginal ear vein
- DO NOT FAST patient at all
40
Rabbit anaesthesia what is involved withe premedication, induction and maintenance
Premedication
○ Opioid and sedation
○ Oxygenation before give drugs - IMPORTANT
○ Quiet, calm, be gentle but restrain well, turn light of to work
Induction
○ IV or IM
Maintenance
○ Gaseous per tube (intubate) or mask (harder to ventilate, but positive pressure ventilation on the nose)
○ Circuit for patients less than 10Kg/5Kg
41
What are the 7 steps in incubating a rabbit
1. Sternal recumbency, neck extended, head parallel to bench
2. Otoscope with largest possible cone
3. Hold tongue gently, pass scope in to view pharynx
4. Use tube to dislodge epiglottis from soft palate
5. Spray larynx once with local anaesthetic
6. Insert tube down through cone
7. Check (condensations not tube, air flow from tube, capnography)
42
Rabbit anaesthesia monitoring what is important
- Use your eyes, hands and stethoscope
- Pulse oximetry
○ Ear
- Oscillometric blood pressure cuffs
- Temperature
- Reversal and supportive medications
○ Glucopyrrolate/atropine for HR and BP
○ Ephedrine/dopamine for BP
43
Rabbit anaglesia and post op care what is important
```
- Additional analgesia for surgery
○ Local anaesthesia
§ Lignocaine <4mg/kg
§ Bupivicaine <2mg/kg
- Post op
○ Meloxicam 0.5-1mg/kg s/c then orally q24hr
○ Buprenorphine orally q6-8hrly
○ heat
○ Feeding, feeding, feeding
```
44
Guinea pigs design features and how works with pre-anaesthetic examination and preparation
```
Design features and patient preparation
- Nasal breathers, palatal ostium
- Can't regurgitate but have cheek pouches
○ High risk for aspiration
- High risk gut stasis as per rabbits
- Very thick skin compared to rabbits
Pre anaesthetic examination
- GIT and respiratory focus
Patient preparation
- Flush cheek pouches
```
45
Guinea pigs anaesthesia and post op care compared to rabbits
- Sedation, analgesia and induction
○ Induction very similar to rabbits but higher dose rates
○ Intubation only possible with rigid scope so mostly use mask
Post op care
- Analgesia
- Assisted feeding
- Heat
46
Ferrets what are important physiological characteristics for anaesthesia
- Fast inside and out - 4-6 hours before surgery
- Carnivores, strong smell so don't house them with the rabbit, rodents and birds
- Strong jaw tone that is slow to decrease under GA
- Wide gape good for intubation
- Rapid gut transit time so short fasting
- They can regurgitate
47
Ferrets what is important with pre-anaesthetic examination and patient preparation
Pre-anaesthetic examination as per cats and dogs
- Be alert for endocrine disease signs
○ Symmetrical alopecia
○ Pale mucosae
○ Enlarged vulva
Patient preparation
- Fast adults for no more than 4 hours and pre-weaned kits for 1 hour only
- Measure haematocrit and blood glucose
- Post op feed as soon as awake and mobile
48
Ferrets anaesthesia what involved with premedication, induction, maintenance, monitoring, analgesia and post-op care
Premedication– Acepromazine (long acting), butorphanol, Medetomidine with butorphanol
Induction – Alfaxan IV
Maintenance – Isoflurane per mask
Monitoring – as other species
Analgesia – Meloxicam/carprofen/buprenorphine
Post-op care – as other species
49
Parrot special features important for anaesthesia
- Fleshy tongue obscures glottis
- Small trachea (complete rings) and bifurcation at syrinx
- Extremely efficient and rapid gas exchange
- Air sacs (compress easily so don't squeeze)
- Lose heat easily
Cages birds often very unfit with poor diet
50
What are important parts of the pre-anaesthetic examination and patient preparation for parrots
- Observe without handling first
- Handling precautions
- Measurements
○ Haematocrit, blood protein, weigh, HR (over 6 seconds)
- Crop palpation (should be empty)
Budgie -> fast for 1 hour
Patient preparation
- Fast large parrots 2-4 hours
- Fast small parrots 1 hour
- Draw up all medications
51
Anaesthesia for parrots - premed, anaglesia, induction and maintenance
```
Premedication
○ Premed
§ Midazolam IM - anxiolytic
○ Analgesia
§ Butorphanol CONTINUE
Induction and maintenance
○ Isofluorane per bespoke mask
○ Intubation
○ Ayre's T-piece or Bain's coaxial circuits
○ IPPV often needed as hypercapnea and breath holding common
§ 30-40 breaths per minute
§ Ventilator peak inspiratory pressure <5cm H20
```
52
Parrot anaesthetics support and post-op care
```
- Patient care
○ Heat
○ Fluids (always warmed)
- Post op care
○ Extubate at last possible moment, check for clear airway
○ Oxygen flow-by until fully conscious
○ Feed as soon as co-ordinated again
○ Pain relief
```
53
Reptile general features that are important for anaesthetics
- Thermoregulation
○ Temp affects metabolism of drugs
○ Preferred body temperature is species specific
- Anatomical and physiological features
○ Heart - physiological division of blood flow in ventricle
§ Can divert away from lungs if not breathing
○ Lungs - sac like and extend further caudal than in mammals
○ Kidneys - renal portal system
54
Reptile what is involved with pre-anaesthetic examination and patient preparation
```
General pre-anaesthetic examination
- Weigh
- Assess muscle condition
- Measure respiratory rate and note effort or noise
- Measure heart rate (doppler probe)
Patient preparation
- Fast for 24-72 hours
○ Snake at least 72 hours
- Warm to preferred body temp
```
55
Reptiles what use for anaglesia
- Not easy to determine how effective the pain relief is
- Morphine/Methadone commonly used
Use local blocks during anaesthesia whenever possible
- butorphanol - anaglesia in reptiles
56
Reptiles what use in for premed, induction and maintenance
Premedication
○ Opioids alone - morphine
○ Or add ketamine +/- alpha 2
Induction
○ Injectable agents IV (into caudal vein)
§ Propofol/Alfaxan
○ Isoflurane via ET tube and IPPV (inter positive pressure ventilation
Maintenance
○ IPPV manually 2-4 breaths per minute or with ventilator (pressure <10cmH20)
○ Non-rebreathing circuits
57
What are important aspects of monitoring, support and recovery for reptile anaesthesia
- Doppler over heart, capnography, (assess changes rather than absolute values)
- Cloacal or oesphageal temperature
- Heat pads/lamps/warm fluid bags
- Fluid support
- Recovery on room air IPPV at continue
58
Australian mammal anesthesia handling, premed, anaglesia, induction and maintenance examples
- Handle possums inside pillow slip or towel
- Hold koala firmly against pillow or towel roll
- IM sedation with diazepam
- Buprenorphine IM - pain relief
- Alfaxan IM
- Pre oxygenate if available
- Isofluorane per mask or alfaxan IV via cephalic
59
What is the normal respiratory rate and heart rate for horses as well as temperature
normal resting respiratory rate is 8-16 breaths per minute
Normal resting heart rate of a horse is 28-40 beats/min
Normal resting adult range is 37 - 38.4 degree Celsius
60
What are 4 important questions to ask in terms of ECG
1. HR and rhythm?
○ Tachycardia, bradycardia
2. Are the QRS complexes normal ?
○ If normal - good ventricular rhythm
3. Is there a P wave in front of every QRS complex ?
○ If ventricular issues
○ Activity of the sinus nerve
4. Is there a QRS complex after every P wave ?
○ Do I have a AV block - if P waves not always related to QRS complex
61
What are the 3 main waves of the ECG trace and what do they represent
1. P wave depolarisation of atria
2. QRS complex ventricular depolarisation
- Q and S are negative as vectors facing towards atrium
3. T wave ventricular repolarisation
62
Endotracheal tube cuff inflation what does it provide, what can overinflation cause and how to check for leaks
- Allows sealing of the airway to prevent aspiration and to provide positive-pressure ventilation without air leaking
- Over inflation of the cuff can cause necrosis and stenosis of the tracheal mucosa.
Turn off O2 and pop off valve, and listen for a leak at the same time than someone else is giving a breath to your patient.
- If a leak is present, inject air into the cuff while listening and until the leak has disappeared.
63
How to use a laryngoscope
- Don't put your hand in the mouth, use laryngoscope to guide tongue to the side for assistant to grab
- Place laryngoscope rostral to the epiglottis and move tube into the lumen of the glottis
- Check that there is humid air moving in and out of the tube
64
What are 4 indications for mechanical ventilation and what are 2 risks associated
- General anaesthesia -> don't have to do for all animals
- Oxygenation failure: Low PaO2 even with O2 therapy
- Ventilation failure: High CO2
- Post cardio-pulmonary resuscitation
Risk:
- Oxygen toxicity (decreases pulmonary function, pulmonary oedema, species-specific)
○ More common in humans than animals - only really occurs after 24 hours of 100% oxygen
- Barotrauma, cardiovascular depression, infection
65
What is the anaesthesia machine made up of (2 parts) and what occurs
Anaesthesia machine + re-breathing system
- O2 flow meter -> vaporizer -> breathing system
Re-breathing system
- Blue -> rich in O2
- Red -> rich in CO2 back into rebreathing bag
○ Into soda lime removing CO2 and move back into the patient
Ventilator is generally placed where the rebreathing bag is on the system
66
What are the 2 main modes of mechanical ventilation and what control respiratory rate etc.
1) CMV: controlled mandatory ventilation
○ No consideration of patient breathing effort -> you dictate the respiratory rate
○ Control volume or pressure, and respiratory rate
2) PEEP: Positive end expiratory pressure
○ Patient mechanically ventilated
§ Everything controlled with the ventilator
67
What are the parameters that influence oxygen delivery and cardiac output
1) Oxygen delivery -> DO2 = CaO2 X CO
Ca O2 = arterial oxygen content = amount of haemoglobin and saturation of haemoglobin
2) CO = cardiac output = SV x HR
SV -> high preload, high contractility and low afterload
68
How to monitor HR and arterial blood pressure
1) HR from ECG, Pulse oximeter, stethoscope
2) BP - two ways
1. Non-invasive blood pressure: for routine cases is related to heart rate
§ Such as a cuff
§ IF choose a curve that is too small -> artificially reading of too high and vice versa
□ However can
2. Invasive blood pressure: higher risk cases
§ Catheter inside the artery - more accurate reading
69
What are the 4 important aspects of respiratory function that you need to monitor
- Respiratory rate, rhythm and effort,
- Haemoglobin oxygen saturation
- EtCO2
- Arterial blood gases
70
What are the 2 types of pulse oximeters and how works
1) PO (transmission) - most common
Monitor detects pulse after light moves through the tissue
- Difference absorbance of wavelengths -> difference between haemoglobin with and without oxygen to give saturation readings
2) RPO (reflectance) - not as common
- instead of through tissue reflects on the tissue
- Used on the tongue, lips, vulva
71
Pulse oximeter what level is considered hypoxaemic and what is the issue with this measurement
Hypoxaemia -> when PO2 is less than 60mmHg -> 60 related to about 89% oxygen saturation
Problem
- % saturation of oxygen doesn't change that much between PO2 of 600-60 mmHg so may tell you are in an issue NOW which could be given too late
○ Horses mainly -> don't go into recovery until PO2 120mmHg (cannot tell with pulse oximetry)
72
What are 5 important causes of hypoxaemia
1. Reduce partial pressure of oxygen in the inspired air
2. Alveolar hypoventilation
3. Ventilation perfusion mismatch
4. Shunt (intracardiac or intrapulmonary)
5. Impaired alveolar-capillary diffusion
73
Capnography what does it monitor, how presented, what is the important value and why important to measure
- Monitoring of the alveolar partial pressure of carbon dioxide
Usually presented as a graph of expiratory CO2 over time
End tidal value -> is the most important value
Why
CO2 is transported as bicarbonate -> increase CO2 -> increase bicarbonate -> decrease pH of your blood
○ Outside regular range of pH will lead to denaturing of proteins -> cannot function properly
74
Define TIVA, PIVA and balance anaesthesia
- TIVA = Total Intravenous Anaesthesia – only IV agents used to provide balanced anaesthesia
- PIVA = Partial Intravenous Anaesthesia – inhalant and IV agents used concurrently to provide balanced anaesthesia
- Balance Anaesthesia = Judicious use of hypnotic and analgesic agents to minimise side-effects of each while providing anaesthesia and analgesia
75
What are the cardiovascular and central nervous system hazards for inhalants
Cardiovascular
○ cardiovascular depression (enflurane>halothane>isoflurane)
§ All gas have these effects
○ cardiovascular stimulation (desflurane)
§ If increase too fast - sympathetic storm -> tachycardic and hypertensive
Central nervous system
○ cerebral vasodilation -> increase intracranial pressure - DON'T USE
○ epileptic activity (enflurane)
76
What are the respiratory and toxicity hazards of inhalants
Respiratory
○ irritancy (des>iso>halothane)
§ Don't mask a patient down with desflurane
○ block hypoxic pulmonary vasoconstriction
§ Shunt the blood from collapsed alveoli to alveoli that are active
§ Increase risk of hypoxaemia if patient is on the side and the alveoli on that side are collapsed but blood still going there as this reflex is blocked
Toxicity
○ nephrotoxicity (methoxyflurane, sevo?)
- hepatotoxicity (all)
○ malignant hyperthermia
○ operating room pollution
77
Hazards of nitrous oxide what are the 3 main ones
1) diffusion into gas-filled areas
○ gastrointestinal tract - horses and cattle have high levels of gas in their stomach
- pneumothorax / trauma cases
2) air embolism
3) bone marrow toxicity, nervous system, cardiovascular, hepatic, and reproductive effects in humans IF CHRONICALLY EXPOSED
78
In terms of the environment which is more friendly Hydrochloroflurocarbons or nitrous oxide
Hydrochlorofluorocarbons - considered ozone friendly as lifetime of only 5-6 years
Nitrous oxide - very stable in atmosphere (150yrs), destroys ozone
79
What are 6 main advantages of using intravenous anaesthesia and 1 limitation
- better for environemnt
- rapid, smooth induction
- seamless transition from induction to maintenance
- easy to deepen anaesthesia - more rapid than changing ventilation settings
- rapid, predictable recovery of better quality - less likely to have issues
- safe for patients with MH, asthma and other allergic
conditions
Dis
- expensive (alfaxalone > propofol)
80
List the 4 delievery systems for intravenous anaesthesia
1) intermittent bolus
2) constant rate infusion (CRI)
3) Variable rate infusion
4) target controlled infusion - best practice
81
Intermittent bolus as delievery system for intravenous anaesthetics what okay for, advantages and disadvantages
○ Okay for short cases (<5-10mins)
§ Give bolus, when lighter give another bolus, etc. - cannot do this forever
ADV
- Simple
- no speciial equipment needed
DIS
○ Poor quality (peaks and troughs) anaesthetics level at the brain goes up and down
○ Large total drug dose than continuous infusion - MORE side effects
○ Slow recovery
82
What are the important characteristics of constant rate infusion, variable rate infusion and target controlled infusion
Constant rate infusion (CRI)
○ Smoother anaesthesia
○ Deeper with time - overtime will accumulate slightly
○ Risk of awareness (longer time for induction) or side effects (rate)
- better if give bolus than CRI
Variable rate infusion - most common
○ Smoother
- Lower total drug dose
○ Faster recovery
○ Frequent adjustment needed
Target Controlled Infusion - best practice
○ A computer
○ A set of PK (pharmacokinetics) parameters specific for a given agent and a given population
- Gives you the concentration that you want for the whole time
§ Propofol want 3,000 concentration
83
Co-infusion what are the 3 options to use with porpofol or alfaxalone and why choose
OPIOIDS - with similar profile (easily titratable, rapid recover)
1. traditional opioids - morphine and pethidine - ODN'T USE
2. fentanyl - use for shorter surgeries - 20-30min
3. remifentanil - what we want to use especially in long surgeries, rapid recovery
84
What is the difference between an antibiotic and antimicrobial
antibiotic - small molecular substance produced by microorganism that kills other microorgansisms
antimicrobial - any substance, natural synthetic that kills microorganisms
All antibiotics are antimicrobials, but not all antimicrobials are antibiotics.
85
What are 6 important factors in choosing an antibiotic
1. Legally prescribing and dispensing
2. An appropriate active ingredient
3. That gets to the site of infection
4. At levels above the MIC
5. For an appropriate period
6. Taking into account:
- prudent use of antibiotics
- Cost
- Compliance
- Drug interactions
86
Gram positive bacteria what are the two types and microorganisms within
1) Cocci
○ Only 2 groups –Staphylococcus and Streptococcus
○ Differentiate with catalase test
2) Rods
○ Bacillus, Clostridia, Corynebacterium, Listeria, Nocardia, Actinomyces,
87
What are the 4 groups of gram megative bacteria and examples or bacteria within
1. Oxidase –ve
○ Enterobacteria – E. coli, Salmonella, Klebsiella, Yersinia, Proteus - gastrointestinal
2. Oxidase +ve -> turn purple with oxidase test
○ Rods -Pseudomonas, Pastuerella, Hemophilus, Taylorella, Brucella, Bordetella, Actinobacillus
○ Spiral ones –Campylobacter, Lepto, Spirochetes
3. Gram negatives that behave like gram positives - use gram positive antibiotics on them
○ Moraxella and Fusobacterium (penicillin)
4. Acid Fast
○ Some class acid fast with the gram negatives
○ Mycobacteria (Norcardia)
88
What are the 8 common classes of antibiotics in vet medicine and which do what bacteria
1. Penicillins
2. Cephalosporins
3. Macrolides
1-3 gram positive
4. Aminoglycosides - NARROW GRAM NEGATIVE
5. Tetracyclines
6. Sulfonamides
7. Fluoroquinolones
8. Metronidazole
5-8 - broad spectrum
89
Which 2 antibiotics only really used in small animals and large animals
```
Small animal
1. fluroquinolones
2. metronidazole
Large animal
1. macrolides
2. aminoglycosides
```
90
Pencillins what are the 4 different types and there spectrum/beta lactamse resistance
1) Pencillin G - Gram positive but beta-lactamase sensitive
2) Amoxycillin - gram positive and negative but beta-lactamase sensitive
3) Cloxacillin - gram positive and beta-lactamase resistant
4) Clavulanic acid -> BOTH gram positive and negative AND breaks down beta-lactamase so resistant
- WHY PRESENT
91
Cephalosporins what are the 4 classifications, what changes and main disease/animals use for
- Classified into “generations”, with increasing spectrum of activity
1) Cephalexin (1st Generation)
○ common in SA practice - the only common cephalosporin in dog/cats
§ especially skin, urine, osteomyelitis
○ resistant to β-lactamase from staphs (not enterobactria)
2) Cefurioxime (2nd Generation)
○ Mastitis in cattle
3) Ceftiofur (third generation)
- Respiratory disease in cattle, horses
○ Expensive
4) Cefovecin (third generation) - Convenia
○ Very long acting -> but resistance issue
In general, the use of 3rd generations is avoided in animals for resistance reasons.
92
Aminoglycosides what end in, 4 examples, spectrum of activity, side effects and important info
- The opposite of the macrolides, but still end in –mycin
- Neomycin, Streptomycin, Gentamycin, Tulathromycin –large animals mostly
- Gram –ve and Staphylococcus (not streps) - only narrow gram negative
- Nephrotoxicity, and residues in kidneys - not used in small and not really in large animals
- Streptomycin and Gentamycin BANNED in food producing animals
- Must not use gentamycin unless specifically indicated
93
Tetreacyclines how common, spectrum of activity, what are the 2 main drugs and what used in
Highest use antibiotic in vet medicine. Broad spectrum, safe and cheap
Doxycycline - small animals
Oxytetracyclin - large animals (cattle)
94
Sulfonamides spectrum of activity, what mostly used for, examples and where good penetration
- Broad spectrum, usually combined with trimethoprim
- Mostly used for diarrhoea in large animals
- Excellent against staphs; some resistance in streps - mastitis decisions
EG - Sulfadimidine, sulfatroxazole, sulfadiazine, sulfamerazine, sulfadoxazoleetc…
- No particular differences between them except for coccidia (sulfadimidine is best)
- Good penetration into gut, milk, lungs, urine
95
Fluoroquinolones give example, spectrum of activity, when should you use and when can't you
- Enrofloxacin (Baytril) and others
- They treat everything in all species …
- Should avoid their use because of the potential for resistance in human disease
- BANNED IN FOOD PRODUCING ANIMALS
96
Metronidazole what used for
- Anaerobic infections
| - Particularly mouths, osteomyelitis, peritonitis
97
what are you allowed to dispense in terms of antibitoics and what do you need before this for small animal and large animal clients
- APVMA registers all products
- Vets can supply human and veterinary antibiotics
If not registered by APVMA, or in a way different to label = “off label”
- Vet takes responsibility for off-label use
- MUST NOT USE ANTIBIOTICS AGAINST A LABEL RESTRAINT
- In small animals
○ Need consent from client
○ Need to be able to justify the use (egto the vet board)
- Also, In food producing animals
○ Single animal treatment only
- Need appropriate withholding period
98
What are the 11 important things needed on label for medication
1. The words ‘KEEP OUT OF REACH OF CHILDREN’ in red on a white background
2. The words ‘FOR ANIMAL TREATMENT ONLY’
3. if the substance is intended for external use only, the word ‘POISON’ or the words ‘FOR EXTERNAL USE ONLY’ in red on a white background;
4. business name, address and telephone number of the veterinary practitioner
5. the identity of the animal(s) to be treated; e.g. tag number, species, breed, age, sex
6. the name of the animal’s owner or person in charge
7. the date the product was used or sold
8. the trade name
9. the quantity in the container
10. adequate directions for treating the animal with the product including the method of administration, dose rate, dose frequency and number of days of treatment
11. the withholding period or the statement ‘Nil withholding period required’ when treating food producing animals.
99
In terms of antibimicrobial resistance what are the 3 levels of use and examples within
1) High - essential for humans infections EG - 3rd gen cephalosporins and fluroquinolones
2) Medium - other alternatives but less available EG - cloxacillin, clavulox, 1st gen cephalsporins
3) Low - reasonable alternatives EG - penicillins, tetracycline, neomycin, erythromycin
100
What are 4 important AVA guidelines for obligations of the prescribing veterinarian
- Report all suspected adverse drug experiences
- Review patient or farm records to ensure compliance with prescribing label instructions.
- Evaluate the response to previous treatment before again prescribing antimicrobials.
- Maintain a high level of awareness of the problem of antimicrobial resistance in humans and prudent use of antimicrobials in animals and communicate this to clients.
