Anaesthesia (SA) Flashcards
1
Q
What is an ASA grade I patient?
A
Normal and Healthy
2
Q
What is an ASA grade II patient?
A
Mild systemic Disease
3
Q
What is an ASA grade III patient?
A
Severe systemic Dz
4
Q
What is an ASA grade IV patient?
A
Severe systemic Dz that is a constant threat to life
5
Q
What is an ASA grade V patient?
A
Moribund - will not survive without surgery
6
Q
What is an ASA grade E patient?
A
Emergency
7
Q
What is the difference between pain an nociception?
A
Pain is recognised by the brain at a cortical level.
8
Q
What are the four stages of nociception?
A
Transduction
Transmission
Modulation
Perception
9
Q
What is “transduction”? (with regard to nociception)
A
Conversion of stimulus into AP by nerve end receptors
10
Q
How is stimulus intensity conveyed during “transduction” of nociception?
A
frequency of AP generation
11
Q
What is “transmission”? (with regard to nociception)
A
Conduction of impulses to/from CNS.
12
Q
Where do sensory impulses enter the CNS?
A
Dorsal Root
13
Q
Where do motor impulses exit the CNS?
A
Ventral Root
14
Q
What is “modulation”? (with regard to nociception)
A
Amplification/suppression of nociceptive input at spinal cord level
15
Q
How does modulation of nociception take place?
A
Aletered neuronal sensitivity/altered neurotransmitter release
16
Q
What is “perception”? (with regard to nociception)
A
Processing, integration and recognition of stimulus in HIGHER centres. MUST BE CONSCIOUS.
17
Q
What is acute pain often associated with?
A
Tissue Damage (or the threat of)
18
Q
What is chronic pain?
A
Pain which persists beyond the expected course. NO purpose or clear end-point.
19
Q
Define Neuropathic Pain
A
Pain caused by nervous system dysfunction
20
Q
Define Allodynia
A
Perception of pain when a normally non-noxious stimulus is applied
21
Q
Define Hyperalgesia
A
An excessive reaction to a noxious stimulus
22
Q
Which sensory neurons are “low threshold sensory nerves”?
A
A Beta
23
Q
Which sensory neurons are “medium threshold pain nerves”?
A
A Delta
24
Q
Which sensory neurons are “high threshold pain nerves”?
A
C
25
Which are the principal neurotransmitters involved with central modulation?
Serotonin
| Nor-adrenaline
26
How can we reduce pain sensitisation?
Avoid experience of pain
| Treat Pain aggressively
27
Which Analgesics work at the nerve terminal level?
NSAIDs
Local Anaesthetics
Opiates
28
Which analgesics work in the dorsal horn of the spinal cord?
```
NSAIDs
Opiates
NMDA antagonists
Ca Channel Blockers
Tramadol
```
29
Which analgesics work in the brainstem/cerebrum?
```
NSAIDs
Opiates
NMDA antagonists
Ca Channel Blockers
Tramadol
```
30
What are the 7 classes of drugs for acute pain?
NO PLANT
```
NSAID
Opiate
Paracetamol
Local Anaesthetics
Alpha 2 Agonists
NMDA antagonist
Tramadol
```
31
Name 6 drugs that may be used to treat chronic pain. (not NO PLANT)
```
Gabapentin
Amantidine
Anti-depressants
Green-lipped mussel
Elk Velvet Antler
Capsacin
```
32
What are the 4 goals of sedation?
Relive Anxiety
Ease Handling
Analgesia
Decrease Muscle Tone
33
What are the 3 formulations of ACP?
2mg/ml
5mg/ml
10mg/ml
34
What is an appropriate dose for ACP in the dog?
0.01-0.05mg/kg (lower if IV/large dog)
35
What is an appropriate dose for ACP in the cat/
0.03-0.07mg/kg
36
How is ACP administered?
IM/IV/SC in smallies
IM ONLY IN HORSES
37
What is the time to onset for ACP?
30min
38
How long is the duration of ACP?
3-8h
39
How does ACP work?
anti-dopaminergic
40
How does ACP interact with other sedatives?
Potentiates their CNS depression
41
How does ACP cause vasodilation?
Alpha 1 adrenergic blockade
42
How does ACP affect respiratory function?
Not much EXCEPT pharyngeal relaxation (bad for brachys)
43
Describe the hepatic/renal toxicity of ACP
Not Applicable - no direct effects
44
What are some potentially beneficial off-target effects of ACP?
Anti-emetic
| Anti-histaminic
45
What CV SE would make ACP contraindicated in boxers and brahcycephalics?
Can cause syncope
46
What Haem/biochem abnormality may ACP cause?
Decreased PCV
47
What analgesic effect does ACP offer?
NONE!
48
Where is ACP metabolised?
Liver - no significant metabolites
49
At high doses, what symptoms may ACP trigger?
Extrapyramidal - rigidity/tremors
50
Which drug is CI'ed with ACP?
Epinephrine - Beta agonist so will cause even more vasodilation/hypotension
51
Which alpha two agonists may be used in cats and dogs?
Medetomidine
| Dexmdetomidine
52
Which alpha 2 agonists may be used in horses?
Xylazine
Detomidine
Romifidine
(+medetomidine)
53
Via which route are a2 agonists administered?
IM/SC/IV
54
How to alpha 2 agonists initiate sedation?
agonists of alpha 2 in locus coeruleus in the brainstem
55
How do a2 agonists affect administration of other sedatives?
REDUCE DOSE!
56
Describe the CV effects following a2 agonist administration.
Initial vasoconstriction
Reflex Bradycardia
Vasodilation
57
How do a2 agonists affect the respiratory system?
Reduce RR
| May alter R pattern
58
What analgesic effect does an a2 agonist have?
Good - but sedative lasts 2-3x longer.
59
How do alpha 2 agonists affect the kidneys?
Cause diuresis
60
How do alpha 2 agonists affect GI motility?
Decrease it
61
How do alpha 2 agonists affect blood sugar?
Cause hyperglycaemia - decrease insulin secretion
62
Where are a2 agonists metabolised?
Liver
63
Name the alpha 2 antagonist commonly used.
Atipamezole
64
In which animals are A2 agonists CI'ed?
DCM
| MVD
65
Which benzodiazepines are commonly used in veterinary anaesthesia?
Midazolam
| Diazepam
66
Which benzodiazepines are licenced for veterinary anaesthesia?
None
67
What dosage is used for benzodiazepines as part of an anaesthesia protocol?
0.2mg/kg
68
What dosage is used for benzodiazepines to control seizures?
0.5mg/kg
69
via which route can midazolam but NOT diazepam be given?
IM
70
via which route can diazepam but NOT midazolam be given?
Oral (not in cats)
71
How long does onset of benzodiazepines take following administration?
Minutes
72
Which benzodiazpine has the shorter DOA and faster onset?
Midazolam
73
How do benzodiazepines induce sedation?
Binding to specific sites on GABA receptor in brain and SC
74
What effect do benzodiazepines have on the heart (at a normal dose)?
minimal
75
What are the potential CVS side effects caused by the propylene glycol found in diazepam?
Haemolysis, CV arrhythmias and hypotension
76
What effect do benzodiazepines have on the resp system?
Minimal but will enhance effect of other drugs
77
What is an occasional liver SE of benzodiazepine use in cats?
Fulminant Hepatic Failure
78
Which haem/biochem abnormality would increase the free fraction of benzodiazepines, leading to a greater effect?
Hypoproteinaemia
79
In which animals are benzodiazepines CI'ed?
PSS
Severe Hepatic disease
Hepatic Encephalopathy
80
What may occur if benzodiazepines are given to young, excitable animals w/o sedation?
Excitement
| Disinhibition
81
Why is diazepam less suitable than midazolam for infusion? (2)
Many active metabolites that may undergo enterohepatic recycling/accumulation
AND
May bind to some plastics
82
Name 2 drugs that may reverse the action of benzodiazepines?
Flumazenil
| Surmazenil
83
Name two commonly used veterinary barbiturates.
Thiopental
| Pentobarbital
84
What class of drug does alfaxalone come under?
Neurosteroid
85
Which class of drug does propofol fall under?
Phenol
86
Name the most common phencyclidine derivative used in veterinary medicine.
Ketamine
87
Which barbiturate is "ultra-short" acting and how long does it last?
Thiopental
5-15min
88
Which barbiturate is "short" acting and how long does it last?
Pentobarbital
45-90min
89
How long does reconstituted thiopental last?
6d
90
What is the pH of thiopental and why is this significant?
10.5 - very irritant so IV only and CARE with extrvasation
91
What is the site of action for thiopental?
GABAa
92
What is the onset for thiopental and why?
20-40s
V lipid soluble so crosses BBB easily
93
How does thiopental cause arrhythmias?
Causes myocardial sensitisation to catecholamines
94
What direct effect does thiopental have on the heart?
Myocardial depression - negative inotrope
95
What effect does thiopental have on BP?
Vasodilator so causes hypotension
96
How is thiopental cerebroprotective?
Decreased cerebral metabolic rate and blood flow
97
What are the two occasions thipental is used?
Top Up boluses (esp horses)
Induction if intracranial disease
98
In which species is alfaxalone licenced?
Dogs and Cats
99
What is the pH of alfaxalone?
6.5-7 (non irritant)
100
What is the site of action of alfaxalone?
GABAa receptor
101
What CVS effects does administration of alfaxalone have?
Vasodilation with REFLEX tachycardia.
102
What is a potential surgical benefit of using alfaxalone?
Good Muscle Relaxation
103
Describe the analgesic properties of alfaxalone
None
104
Via what route is alfaxalone administered?
IM or IV
105
What is the dose of alfaxalone for dogs?
2mg/kg
106
What is the dose of alfaxalone for cats?
2-3mg/kg
107
What is alfaxalone used for?
Induction/maintenance of smallies
OR
Sedation
108
In what species is propofol licenced?
Dogs and Cats
109
What is the site of action for propfol?
GABAa receptor?
110
What is the pH of Propofol?
7.8
111
What CVS effects does administration of propofol have?
Mildly negative inotrope
Vasodilation
Hypotension
112
How is propofol cerebroprotective?
Decreased cerebral metabolic rate and blood flow
113
Describe the analgesic properties of propofol.
none
114
What must be noted about propofol administration in cats?
CAN ACCUMULATE
115
How is propofol metabolised?
Rapidly in the liver.
| ALSO lung, kidney and GI
116
What common side effect is seen with propofol administration in cats?
Heinz Body Anaemia
117
What is the reccomended dose for propofol?
2-6mg/kg
118
How should propofol be administered?
IV!!! ONLY!
119
Which species is ketamine licenced in?
Cats, Dogs and Horses
120
What is the pH of ketamine?
4
121
Which isomer of ketamine is more potent?
S(+) > R (-)
122
What is the site of action for ketamine?
NDMA receptor - antagonist
123
What is the onset of action for ketamine?
1-2min
124
What is the overall effect of ketamine on the CVS?
Sympathetic activation (inc HR, CO, BP)
125
Why is the overall CVS effect of ketamine counter-intuitive?
Directly depresses myocardium - would not expect inc CO
126
What is the effect of Ketamine of the resp system?
minimal resp depression but strange breathing pattern
127
How does ketamine increase ICP?
promotes cerebral blood flow
128
How does ketamine increase IOP?
increases extraocular muscle tone
129
Why should ketamine be administered alongside a benzodiazepine?
Poor muscle relaxant
130
How is ketamine metabolised?
In the liver - to norketamine
EXCEPT IN CATS! urinary excretion unchanged.
131
how is ketamine administered? which route is preferable and why?
IV or IM
IM can be painful so IV preferable
132
What is the dose for induction using ketamine in:
a) dogs
b) cats
C) horses?
Dog: 2.5mg/kg
Cat: 3-5mg/kg
Horse: 2.2mg/kg
133
What is the dose for analgesia using ketamine?
0.1-0.5mg/kg
134
What is the difference between ketamine and tiletamine?
Tiletamine has a longer DOA
135
What is the pH of tiletamine and why is this significant?
2-3.5 PAINFUL
136
What receptor does Tiletamine act on?
NDMA
137
When do we use Tiletamine?
Zoo/Wild animal darting
138
What is the dosage for tiletamine induciton?
5-7mg/kg
139
What route is tiletamine administered by?
IM or IV
140
What are the two extracellular compartments?
Interstitial
| Intravascular
141
What % of body weight is Intracellular fluid?
40%
142
What % of body weight is extracellular fluid?
20%
143
What % of body weight is Interstitial fluid?
15%
144
What % of canine/equine body weight is plasma?
8-9%
145
What % of feline/rabbit/ruminant body weight is plasma?
6-7%
146
What are the 4 types of fluid loss?
Pure Water
Water and electrolytes
Water, electrolytes & protein
Blood
147
What fluids should be used to replace water?
Crystalloid - Low Na+
| 5% glucose or 4% glucose + NaCl
148
What fluids should be used to replace ECF?
Balanced Crystalloid (Hartmanns or 0.9% NaCl)
149
What fluids should be used to replace ECF with protein?
Colloids
150
What fluids should be used to replace blood?
Colloid + Crystalloid
| Blood
151
What are the signs of <5% dehydration?
None
152
What are the signs of 5-7% dehydration?
Tacky/dry oral MMs, Normal/Dec skin turgor
153
What are the signs of 8-10% dehydration?
V. dry oral MM
Dull/sunken eyes
Loss of skin turgor
154
What are the signs of 10-12% dehydration?
Dry MM,
Sunk eyes
Loss of turgor
Altered mentation
155
What are the signs of 12-15% dehydration?
All signs of lower level dehydration
| + dying
156
What does CRT give us an indication of?
Blood volume
| Capillary tone
157
What does a CRT <1s indicate?
Poor Perfusion or Hypovolaemia
158
What does a CRT >2s indicate?
Septic Shock
159
What is the equation for calculating BP?
BP = SV x HR
160
What should normal systolic BP range be?
90-160
161
What should normal MAP range be?
60-140
162
What is the normal RR for a dog/cat?
10-30bpm
163
Which drug(s) may cause tachypnoea?
Methadone
164
Which drug(s) may cause bradypnoea?
Isoflurane, propofol, fentanyl
165
What is the consequence of increased dead space?
Hypoventilation leading to hypercapnia and tachypnoea
166
What is the normal range of expiratory CO2?
35-45mmHg
167
What value should PaO2 be above?
96%
168
What is the normal temperature range for a dog?
37.5-39 Degrees celsius
169
Which drug should be avoided if there is a worry of hypothermia and why?
ACP - vasodilation and reset of hypothermic threshold
170
What should the cuff size be for oscillometric BP?
40% of circumf of limb
171
What are 4 potential complications of invasive BP monitoring?
Infection
Thrombosis
Embolism
Haemorrhage
172
Which negative inotrope may be given as a CRI to manage BP?
Dobutamine ( B1 adrenergic agonist - CARDIOSELECTIVE)
173
Which + inotrope can be used in a dose-dependent fashion to control BP?
Dopamine
174
Which 2 drugs can be used to induce vasoconstriction?
Phenylephrine
| Nor-adrenaline
175
What % of blood volume does the venous system hold?
60%
176
Where does oedema usually build up in venous overload?
Limbs
| Under Jaw
177
Why does GA tend to cause hypercapnia?
Reduced medulla sensitivity
178
What type of acid/base abnormality is caused by uncorrected hypercapnia?
Respiratory Acidosis
179
What capnographic sign demonstrates rebreathing?
Progressive increase in respiratory baseline
180
What are 3 possible causes of rebreathing Co2?
Exhausted soda lime
Low FGF in non-rebreathing system
Leaking expiratory valve
181
What capnographic sign demonstrates hypoventilation?
Progressive increase in Alveolar Plateau.
182
What can we do to correct hypoventilation under GA?
Reduce Depth
IPPV
Check intubation
183
Oscillations in the inspiratory downstroke are caused by what?
Cardiac oscillation
184
What capnographic sign may indicate increased expiratory resistance?
Slow transition to plateau from expiratory upstroke
185
What are 4 possible causes of pulse oximetry error?
Hair/ambient light reduces accuracy
Non-pigmented skin required
Motion = error
Clip exsanguinates thin tissue
