Anaesthesia and analgesia Flashcards

1
Q

Define nociception

A

lack of awareness of painful inputs

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2
Q

Why do we give a premed ?

A

-reduce dose of inducing agent
-reduce dose of maintenance agent
-pre-emptive analgesia
-smooth recovery

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3
Q

List pre med drugs

A

acepromazine ACP
alpha 2 agonist -medetomidine
benzodiazepine - midazolam
alfaxalone
opiod

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4
Q

Describe the use of ACP as a pre med

A

-usually with opiod
-sedation
-cause vasodilation - not good for sick animals
-SC,IM,IV and oral

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5
Q

What alpha 2 agonists do we use for small animals ?

A

medetomidine or dexmedetomidine

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6
Q

What alpha 2 agonists do we use for horses ? ( fast-slowest to kick in )

A

xylazine - fastest
detomidine - middle
romifidine - slowest

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7
Q

What alpha 2 agonists are used in cattle ?

A

xylazine
detomidine

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8
Q

Describe alpha 2 agonist as a pre med

A

-cardiovascular effects
-analgesia
-increase urine production - no blocked cats
-effects glucose - diabetic patients
-not in sick patients
-has reversal agent ( atipamezole )

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9
Q

List examples of benzodiazepines

A

midazolam
diazepam

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10
Q

Describe the action of benzodiazepines as pre meds

A

-no analgesia
-ASA 3 - can use in sick animals
-wide therapuetic index
-avoid in excitable animals
-works on GABA
-reversal ( flumazenil )
- usually combined opiod, ketamine or alfaxalone

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11
Q

Describe the action of alfaxalone

A

-IV and IM
-usually combined opiod
-minimal cardiovascular effects
-painful in large animals IM - large amount

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12
Q
A
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13
Q

List some examples of opiods

A

methadone (dog , cat , horse )
fentanyl ( dog, cat )
butorphanol ( used lot in equine )
buprenorphine ( horse , dog , cat )

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14
Q

Describe the action of opiods as pre med

A

-analgesia
-limited cardiovascular effects

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15
Q

TRUE/FALSE ASA 5 is a healthy animal

A

false

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16
Q

TRUE/FALSE no alpha 2 agonists in sick patients

A

true

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17
Q

List some induction agents

A

propofol
alfaxalone
ketamine

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18
Q

TRUE/FALSE volatile agents are mainly used for maintenance

A

true

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19
Q

What does propofol target ?

A

GABA receptors

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20
Q

State disadvantages and advantages of propofol

A

-rapid uptake
-rapid smooth recovery

-resp and cardiovascular depression - Good to have IPPV breathing system
-no analgesia

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21
Q

What does alfaxalone target ?

A

-GABA receptors

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22
Q

Advantages and disadvantages of alfaxalone as a induction agent

A

-rapid onset of action
-rapid and smooth recovery
-licensed for rabbits too

-resp and cardiovascular depression
-no analgesia

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23
Q

What does ketamine target ?

A

-NMDA receptor antagonist

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24
Q

Advantages and disadvantages of ketamine as an inducing agent

A

-analgesia
-licnesed ruminants,rodents,rabbits ,primates and horses as well as cat and dog

-poor muscle relaxation ( combine with alpha 2 or BZD)
-schedule 2

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25
What in feline triple
opiod,ketamine and alpah 2
26
What in a feline quad ?
opiod , alpha 2 , midazolam and ketamine
27
How do you measure an ET tube ?
nares to point of shoulder
28
TRUE/FALSE = gags are usually required for large animal intubation
true
29
What is a supraglottic airway device ?
v-gel use cats, rabbits
30
Name some non rebreathing systems .
-lack -bain -T piece
31
Name the weight , circuit factor and IPPV ability of a lack and mini lack
-10 kg - 1 -not long term IPPV Mini lack same as above but for 2-10 kg
32
State the weight, CF and IPPV ability of a bain.
-7-30 KG - 2.5 -really good IPPV
33
State the weight , CF and IPPV ability of a T piece .
-less than 10kg -2.5 -IPPV
34
lacks full name
parrallel lack
35
How to do fresh gas flow calculation ?
fresh gas flow per minute=MV x CF TV= 10mls/kg ( so need to x 10 by weight ) MV = TV x RR (20 bpm) = usually 0.2 L CF - of what breathing system you select
36
Name a rebreathing system with weight and IPPV ability .
-circle -10-150 kg ( 30-1000kg in LA ) -IPPV
37
How to calculate fresh gas flow for a circle
-first 10-15 min - 100mls/kg/min(2-4L/min) -then 50ml/kg/min ( 1-2l/min)
38
What is a minimum alveolar conc and how does it help ?
-minimum alveolar conc -how much needed in order to not respond to surgery if didn't have pre med
39
TRUE/FALSE a patient with more fat will have a longer recovery
true - anaesthetic will redistribute into fat and this will act as a reservoir for anaesthetic
40
What do we use to maintain anaesthesia ?
inhalation agents
41
Name some advantages and disadvantages of isoflurane
-less mortality than halothane -licensed - dog, cat, horse, exotics -lower solubility -not washed away as quick -cardiovascular and resp depression
42
Name some advantages and disadvantages of sevoflurane.
-faster induction and recovery -more expensive -not licensed horses -cardiovascular and resp depression
43
What is TIVA and how is it achieved ?
-total intravenous anaesthesia -top up bolus injections (propofol,alfaxalone, ketamine )or continuous rate infusions ( triple drip use equine ,propofol,alfaxalone )
44
What is the triple drip in equine ?
detomidine , guaifenesin , ketamine in fluid bag
45
What is PIVA ? what are the main goals of it ?
-Partial intravenous anaesthesia -reduce MAC , cardiopulmonary depression -additional analgesia -balanced anesthesia e.g use of inhalation agent and lidocaine , ketamine , alpha 2 agonist , opiods - continuous rate infusion or top-up boluses
46
Name ways to establish depth of anaesthesia.
-jaw tone ( brachy maintain some jaw tone, ketamine increase muscle tone ) -eye position -palpebral reflex
47
How can we monitor temperature during surgery ?
-oesophageal temp probe -rectal thermometer
48
What does SpO2 tell us ?
percentage of haemoglobin that is saturated with oxygen normal is about 95%
49
What does capnograph measure ? what does this tell us ?
ventilation -expired (EtCO2 level of CO2 released at end of expired breath ) and inspired CO2 levels -problem ventilation, metabolism(will be impacted by perfusion ) , perfusion
50
Normal EtCO2 in cats and dogs
dog - 35-45mmHg cats- 28-45 mmHg
51
What can low CO2 indicate ?
hyperventilation - CO2 exhaled faster than being produced
52
What can high CO2 indicate ?
hypoventilation - CO2 exhaled slower than its being produced
53
Why treat pain ?
effects us on a sensory , motivational and cognitive level
54
How can measure pain ?
-physiological measurements -pain scales -composite measure pain scale (feline, dog ) , equine pain scale or equine composite pain scale -pain faces and grimace scale ( cats , muzzle tension , orbital tightening ,ear positioning )
55
What drugs can we use to manage pain ?
-NSAIDs -galiprant - joint specific -paracetamol -opiod -preventative analgesia -local anaesthetics -easy to overdose -Alpha 2 agonists - pre medy -ketamine - more for perioperative analgesia , good zoo ,exotics
56
Name some chronic pain scales
helsinki chronic pain index guvquest
57
How do local anaesthetics work ?
-ionised -interact with sodium channels
58
Name local anaesthetics used in vet med .
-procaine -lidocaine -bupivacaine -mepivacaine -proparacaine
59
State some advantages and disadvantages of use of procaine
-rapid -last 40-60 minutes -low toxicity -cattle -low potency
60
State some advantages and disadvantages of lidocaine
-rapid -1-2 hr -low toxicity -all species -low potency
61
Some advantages and disadvantages of bupivacaine
- last 4-6 hours -very high potency -small animals -slow -very high toxicity
62
What species is mepivacaine used in ?
equine
63
Name some blocks
-preincisional -castrate - pre incisional , intra testicular -ovariohysterectomy - direct infiltration of mesovarium ligament , lavage peritoneal cavity with local -eye - retrobulbar (curved or straight needle ) -epidurals - lumbosacral , sacrococcygeal -dental - rostral maxillary ( soft tissue ) , caudal maxilary, mandibular block ( and rostral mandibular ) -IVRA intravenous regional analgesia
64
What's a nerve locater ?
use it to find nerve to administer nerve block
65
TRUE/FALSE only use pure lidocaine IV
true
66
Name 3 local anaesthesia techniques for flank surgery
-line block -inverted L block paravertebral anaesthesia
67
What gauge and length needle would you use for large animal nerve blocks ?
18 gauge , 1 1/2 inch
68
Describe how to do a line block and some properties
-local at varying depths along incision site -unrealiable anaesthesia of peritoneum -slow
69
Describe how to perform an inverted L block and some properties
like a line block but in inverted L shape - block both routes to the flank area -unrealiable anaesthesia of peritoneum -slow
70
Describe how to perform paravertebral anaesthesia .
-T13 , L1, L2 (L3 for caesarean ) -once deep to transverse processes insert local then pull up insert more before coming out -fast -anaesthesia in most of flank - include peritoneum
71
Name some blocks for foot surgery in cattle
-ring block -IVRA
72
What local do we use for cattle ?
procaine
73
What local do we use for horses ?
lignocaine
74
What are the 5 sensory nerve blocks of the head in a horse ?
-supraorbital - frontal nerve 9 branch optic ) -lacrimal -lateral canthus -zygomatic - (zygomatic nerve ) -infratrochlea - Medial canthus -retrobulbar - cilary body nerves
75
What sedatives do we use for cattle ?
xylazine detomidine
76
What GA do we use fro cattle
ketamine
77
What opiods do we use for cattle ?
butorphanol
78
TRUE/FALSE ACP is licensed in horses
true
79
When to avoid using ACP in horses ?
neonates , pregnant , hypotensive , breeding stallions ( effects retractor penis muscle )
80
TRUE/FALSE Brachy at risk of airway obstruction in recovery
true
81
What are some common causes of upper airway obstruction ?
-loss of pharyngeal muscle tone -regurgitation or vomiting -laryngospasm or laryngeal oedema ( especially cats - don't extubate too late -traumatic intubation -brachy
82
Signs of upper airway obstruction
-increased resp noise and effort -abdominal effort -nares flare -"air hunger " - head and neck extended -cyanosis ( late sign ) -restless -agonal breathing ( terminal sign )
83
why high mortality rate in horse anaesthesia ?
-fractures in recovery -post anaesthetic myopathy -neuropathies and spinal cord malacia -intraoperative cardiac arrest -resp obstruction
84
What risk factors increase mortality rates in horses ?
-increase ASA grade -increase age and foals -surgery type and position - dorsal -duration - pressure on parts of body -time of day - in OOH vet tired , less staff -agents - premed TIVA -recovery quality
85
What fresh gas flow rate to use for a large animal circle ?
-start 6-8l/min -after 15 min reduce to 3-4l/min
86
TRUE/FALSE: ACP as a pre med for horses reduces mortality rates
true
87
Common induction agents in equine
-ketamine -benzodiazepine
88
TRUE/FALSE biggest problem with maintenance of anaesthesia in horses is hypotension
true
89
How long does triple drip last ?
45 min
90
What top-up bolus injections can you give to a horse to maintain anaesthesia ?
ketamine 0.5mg/kg every 10 min - can only do for 20 minutes
91
What PIVA can you use for horse and what will this do ?
-ketamine infusion -lidocaien CRI -Alpha 2 agonist infusion -reduce MAC and amount of inhalation agent required
92
State some complications that occur during equine anaesthesia .
-hypotension -hypoxaemia -hypercapnia -bradycardia -tachycardia -neuropathy -eye problems
93
How would you improve hypotension in horse under anaesthesia ?
-positive inotrope - dobutamine -reduce iso -use PIVA -increase fluid
94
How would you improve hypoxaemia in horse under anaesthesia ?
-check not just machine -switch down iso -IPPV -IVFT -tilt head -give beta agonist - salbutamol
95
How would you improve hypercapnia in horse under anaesthesia ?
- can tolerate up to 70 CO2 -reduce iso -IPPV
96
How would you improve bradycardia in horse under anaesthesia ?
-cause - volatile agent? opiod? -if still low give hyoscine N butylbromide
97
How would you improve tachycardia in horse under anaesthesia ?
-cause ? - sympathetic stim ? , CO2 ? -increase depth with ket bolus iv -more analgesia
98
TRUE/FALSE must protect lowermost eye with padding and lubricate when a horse is anesthetised or they'll get corneal ulcers
true
99
What are the optimal timings for a horses movement in recovery ?
-lateral - 30 min -sternal - 10-15 min -standing - 15 min
100
TRUE/FALSE give a low dose sedative while in recovery so horses don't hurt themselves as the anaesthesia wears off
true
101
Name some causes of bradycardia when under GA
-drug -toxaemia -vagus stimulation (e.g if touching eye , gut) -heart problem -hypoxia -hypothermia
102
How to approach bradycardia in anaesthetised patient ?
-look ABP and SPO2 -see if affected -check depth , vagal tone , hypoxia , toxaemia -if drug induced give reversal or give anticholinergics ( e.g atropine )
103
What might cause tachycardia in an anaesthetised patient?
-sympathetic stimulation - too light -abnormalities in ph , CO2 ,O2 -low ABP -drugs
104
How would approach tachycardia in anaesthetised patient ?
-check ABP and O2 -depth of anaesthesia ,CO2 -IV opiod ( fentanyl , methadone) /lidocaine *can increase volatile agent with increase in opioid
105
What might cause a ventricular ectopic beat in the anaesthetised patient ?
-circulating catecholamines ( stress) -hypoxia/hypercapnia -hypovolaemia or hypotension -drugs -myocardial inflammation or stimulation -trauma
106
How would you approach a ventricular ectopic beat in patient under GA ?
-check ABP,O2 -is there risk fibrillation -check depth , CO2 -IV opiod /lidocaine *vaporiser setting increased with opiod
107
What are the common causes of hypotension in GA ?
-anaesthetic drugs -hypovolaemia and haemorrhage -cardiac insufficiency
108
How would you approach hypotension ?
-try determine cause -reduce volatile agent -increase IVFT -re-check ABP -inotrope ( dobutamine ) - make heart pump harder -or vasopressor ( noepinephrine ) -
109
Why would hypercapnia occur in GA ?
-depth -hypoventilation - panty -pyrexia -rebreathing -fresh gas too low
110
Reasons why hypocapnia might occur under GA
-disconnection -mis -intubation -obstruction -hyperventilation -cardiac arrest
111
TRUE/FALSE cats have a higher ET CO2 reading on non-breathing systems
false -its lower
112
TRUE/FALSE = cardiogenic oscillations are an emergency
false - nothing to worry about
113
How would you approach hypoxaemia ?
-replace pulse oximeter probe to check right -check not disconnected -reduce volatile agent -improve perfusion - IVFT, inotropes -ventilate , tilt table if obese -investigate other causes ( haemorrhage , pneumothorax )
114
State some signs of cardiopulmonary arrest
-loss of consciousness -apnoea /agonal gasp -no corneal reflex or palpebral
115
Name reversals / antagonists of alpha 2 , opiod , opiods, benzodiazepine
-alpha 2 - atipam ( atipamezole) -opiod - naloxone -benzodiazepine - flumazenil
116
What is Asystole and PEA and what would you do to correct these ?
-asystole - flat line -PEA - pulseless electrical activity * can look normal -adrenaline - shunts blood from preiphery to heart -vasopressin - peripheral vasoconstriciton -atropine - reduce vagal tone
117
How would you prepare for operation of sick animal ?
-preop bloods -IVFT resuscitation -anti anxiety
118
What pre med would you give to a sick patient ?
-opiod -fentanyl and midazolam -ketamine and midazolam - cats -alfaxalone with opiod *avoid alpha 2 agonists
119
How would you induce a sick patient
-palpate pulse during induction -mucous membranes
120
How is maintenance and monitoring of GA different in sick animal ?
-avoid too much depth -PIVA and TIVA can reduce reliance on volatile agent -IVFT -analgesia , local blocks -emergency drugs ready and calculated -efficiency -warm
121
What does APL stand for and what does it allow ?
-adjustable pressure limiting valve - allows exhaled waste gas and fresh gas to leave the breathing system when pressure within the system exceeds the valves opening pressure
122
TRUE/FALSE don't need to starve rabbits before surgery
true
123
How would you ventilate rabbit?
v-gel
124
TRUE/FALSE you want to keep a rabbit in sternal for as long as you can when undergoing surgery
true ( want to keep thorax higher than abdomen if have to lie on back - so organs don't effect resp rate as much )
125
What would you use to monitor rabbit ?
-capnograph - very important -doppler -temp *SPO2- bv too small ECG - too fast hard to read , hair
126
How would you increase rabbits bp ?
-warm up -drugs - vasopressins -fluids - 10ml/kg for 10-15 min - can do at least 3-4 times -increase heart rate with atropine
127
TRUE/FALSE = red blood cells in bird are nucleated
true *messes up SPO2 reading
128
Where would you administer fluids to bird ?
-iv in wing vein or medialmetitarsal vein -interoseous - easy in birds
129
TRUE/FALSE tortoises will stop metabolising the drugs you've given if the surrounding area is around 30 C
true
130
Why is it important to ventilate tortoises in recovery ?
their breathing isn't stimulated by co2 in blood is triggered by oxygen
131
What are the top 5 anesthetic complications ?
-hypotension -hypothermia -abnormal heart rate -hypoventilation -difficult recovery