Anaesthesia Flashcards
1
Q
Which drug is used to reverse the effects of medetomidine?
A
Atipamezole
Reverses sedation but also analgesia
2
Q
Which drugs can be used as sedatives?
A
Phenothiazines eg acepromazine (2mg/ml SA)
Alpha 2 agonists eg xylazine, Medetomidine, Dexmedetomidine (SA), Detomidine (LA), Romifidine (horses)
Benzodiazepines eg Diazepam, Midazolam
3
Q
Which 2 types of drugs are often used in combination for pre-meds?
A
Opioid and sedative (neurolept-analgesia)
4
Q
Give some examples of opioid analgesic drugs
A
Methadone Pethidine Butorphanol Fentanyl Buprenorphine (Vetergesic)
5
Q
What are the uses of premedication?
A
Reduce the patient’s fear and anxiety and make animal handling easier/safer for us too
Provide pain relief
Reduce the doses of anaesthetic induction (and maintenance) agents required
Prevent/reduce undesirable events (e.g. drug effects on autonomic activity)
Reduce muscle tone
6
Q
Give some examples of injectable anaesthetics
A
Propofol
Alfaxalone
Thiopental
Ketamine
7
Q
Give some examples of inhalational anaesthetics
A
Halothane Isoflurane Sevoflurane Desflurane Nitrous oxide
8
Q
Why, when intubating a cat, do you spray the larynx with topical local anaesthetic solution?
A
Cats are prone to laryngospasm (where the larynx closes)
9
Q
When assessing eye position when an animal is under anaesthesia, under which circumstance may eyes often remain central and open?
A
Under ketamine anaesthesia.
10
Q
How can alpha-2-agonists affect heart ryhthm?
A
Can cause bradyarrythmias (slow, irregular heart rates)
11
Q
What is a thermistor?
A
Attaches to the endotracheal tube connector.
Detects each exhalation, as the exhaled gases are warmer than the inhaled gases. If you want to be warned when less than 3-4 breaths/minute are detected, then the device can be set to alarm when the breathing rate falls below this. These devices are often called ‘Ap-alerts’ – for ‘Apnoea-alert’.
12
Q
Brick red mucous membranes indicate what?
A
Septicaemia or endotoxaemia
These animals may also develop haemorrhages (petechiae or ecchymoses) in their mucous membranes too, which is a sign that they are having problems with their blood clotting, and that they are extremely toxic and very poorly.
13
Q
What is normal capillary refill time?
A
1-2 seconds
14
Q
What are the 3 components we wish to achieve with general anaesthesia?
A
Unconsciousness
Analgesia
Muscle relaxation
15
Q
What do pulse oximeters tell us?
A
Pulse rate
Degree of saturation with oxygen of Hb in arterial blood
16
Q
What saturation values do we expect from an animal under anaesthetic (from pulse oximetry)?
A
96-100%
17
Q
What value should mean arterial pressure be?
A
70mmHg
18
Q
Which value of carbon dioxide should there be in the end tidal breath?
A
Should normally be around 5.3% (40mmHg), and should not exceed around 8% (60mmHg)
19
Q
What is the difference between nociception and pain?
A
Nociception –information regarding a noxious insult relayed from periphery to the central nervous system
Pain – integration and processing of nociceptive input by the brain allowing it to be recognised as pain (implies recognition at the cortical level) (occurs in thalamus)
20
Q
What is the difference between physiological and pathological pain?
A
Physiological – activation of nociceptors by extremes of temperature, pressure or chemical concentrations. Tends to be transient, localised and protective (Aδ fibre mediated) and linked to withdrawal reflexes and behaviour adaptation
Pathological – associated with actual tissue damage, ongoing noxious input and may produce chronic pain states, hyperalgesia and allodynia (the experience of pain from a non-painful stimulation of the skin eg light touch). Acute pathological pain may be protective, but chronic pain disrupts homeostasis, causes suffering and has a significant impact on animal’s behaviour and quality of life
21
Q
Where do Aδ fibres synapse?
A
Laminae I and V.
First pain; mechanical and thermal stimuli
22
Q
Where do C-fibres synapse?
A
Synapse in laminae I and II.
Interneurones connect with lamina V.
Dull persistent pain; chemical, mechanical and thermal stimuli
23
Q
Where do Aβ fibres synapse?
A
Laminae II, III, IV, V
24
Q
Local anaesthetics block which channels?
A
Sodium channels
25
What do 1st order neurones do?
Transmit information from periphery to CNS
26
What do 2nd order neurones do?
2 main types:
Interneurones (located within grey matter): excitatory or inhibitory – local processing and modulation of pain signals
Projection neurones ascend spinal cord to higher centres. Involved in reflex aspects of nociception
27
What do 3rd order neurones do?
Processing, integration and recognition of a harmful or painful experience
28
What is central sensitisation?
Increased second order neurone activity due to recruitment and upregulation of post synaptic receptors in response to sustained or massive release of excitatory neurotransmitters
29
What does central sensitisation result in?
Secondary hyperalgesia – spread of area of increased responsiveness to noxious mechanical (not thermal) around site of primary injury
Secondary allodynia – increased perception of innocuous stimuli as painful
30
Give some examples of drugs which are capable of antagonising NMDA receptors
```
Ketamine
Amantadine
N2O
Pethidine
D-methadone
xenon
```
31
What type of receptor is a NMDA receptor?
Ionotropic glutamate receptor
Activated when glutamate and glycine bind to it
Allows positively-charged ions through
Important in controlling synaptic plasticity and memory function
32
What is meant by synaptic plasticity?
The ability of synapses to strengthen or weaken over time, in response to increases or decreases in their activity
33
Gabapentin blocks which channels?
Calcium
34
How should alfaxolone be given?
im or sc
| Injectable anaesthetic
35
Why might buprenorphine be favourable when choosing an opioid?
Only takes 30 mins to act
36
What is a disadvantage with using NSAIDs?
Reduce renal perfusion
37
What pre-medication would you give a cat in for a spay?
Pre-med: Medetomidine (sedative; alpha-2-agonist) with buprenorphine (opioid)
Induction of anaesthesia: propofol iv
Maintenance: Isofluorane
38
Why should propofol not be used repeatedly in cats?
Can cause Heinz body anaemia and prolonged recovery
39
Give an example of a NMDA antagonist
Ketamine
40
Why is methadone licensed in cats and not morphine?
```
Faster onset (5 mins compared to half an hour), cats can't metabolise morphine to the active metabolites
Methadone has additional analgesia
```
41
What are the advantages of pre-anaesthetic screening?
```
Predicting potential complications
Recognising hidden disease
Owner information
Ability to alter the anaesthetic protocol to suit the individual
Can individualise supportive care
```
42
Why do we want to withhold food from an animal prior to surgery?
Want to reduce abdominal contents:
It puts pressure on the diaphragm
Regurgitation and therefore aspiration risk
43
Describe the ASA grading system scale for patients prior to anaesthesia
I: A normal healthy patient.
II: A patient with mild systemic disease.
III: A patient with severe systemic disease
IV: A patient with severe systemic disease that is a constant threat to life.
V: A moribund patient who is not expected to survive without the operation
E: Emergency
44
Which sedative should you give to an adult horse? Why not any others? (give examples)
Detomidine
Not diazepam: potentially dangerous to use in adult horses-muscle relaxation produced can cause excitement and panic reactions
Not ACP: slow onset with unpredictable results. In an excited animal, collapse from profound hypotension due to 'adrenaline reversal0 can result
Also, neither diazepam nor ACP provide analgesia
45
Why should ACP be used with caution in brachycephalic breeds?
Increases the risk of respiratory obstruction due to the sedation and muscle relaxation produced (inc pharyngeal muscles).
Brachycephalic breeds have a high resting vagal tone (low heart rate), and ACP causes hypotension (low BP) and bradycardia -> can lead to fainting
46
If ACP is being used and hypotension becomes a problem, how can you treat it?
IV fluids and alpha-1 agonists eg phenylephrine
47
Should ACP be used in animals with epilepsy?
Should be used with caution or avoided.
| ACP lowers the seizure threshold in animals with epilepsy.
48
Explain 'adrenaline reversal' with regards to ACP
Excited animals have high amount of circulating adrenaline. Adrenaline preferentially produces vasodilation.
ACP blocks alpha-1 activity, so beta-2 activity takes over: arenaline's beta-2 induced vasodilation can potentiate the alpha-1 blocking effects of ACP, and worsen the vasodilation and hypotension.
49
Which group of sedatives would you use to sedate a foal and why?
Why not any others? (give examples)
Benzodiazepines: CV stability, work well in neonates
Not alpha-2-agonists: profound CV effects may be catastrophic in a compromised neonate
Not ACP: vasodilation accelerates heat loss
50
Which is the only alpha-2-agonist (sedative) licensed for administration via the IM route?
Detomidine
| Also the most potent (only a small volume needs to be injected)
51
How do we prevent the re-breathing of CO2-rich gases in anaesthetic circuits?
Soda-lime cannister absorbs CO2 (rebreathing systems)
| High fresh gas flows ensures CO2 is flushed out of the system between breaths (non-rebreathing systems)
52
What is the average breathing rate of cats and dogs?
10-20 breaths per minute
53
What is the average tidal volume for cats and dogs?
10-20ml/kg
54
How do you calculate minute ventilation?
| What value is it usually?
Breathing rate x tidal volume
200ml/kg/min
55
With regards to minute ventilation, how much fresh gas flow is required for Mapleson A, D, E and F circuits, during spontaneous breathing?
Mapleson A: 1-2 x MV
| Mapleson D, E, F: 2-4 x MV
56
With regards to minute ventilation, how much fresh gas flow is required for Mapleson A, D, E and F circuits, during intermittent positive pressure ventilation?
Mapleson A: 2-4 x MV
| Mapleson D, E, F: 1-2 x MV
57
Give 3 problems with the 'to and fro' model of rebreathing systems
Soda lime dust may be inhaled
Dead space increases as the soda lime exhausts
Channeling can occur-reduces CO2 removal
58
What are the oxygen requirements for a patient in a rebreathing circuit?
4-10ml/kg/min
The bigger the animal, the smaller the value
(4=horse)
(10=dog/cat)
59
For the first 5-20 mins of use of a rebreathing circuit, it is usual to use high fresh gas flows. What values do we use?
Dogs: 2-5 litres/min
Horses: 10 litres/min
60
As a minimum, the patient should be breathing how much inspired O2 in a rebreathing circuit?
33%
61
Explain diffusion hypoxia in relation to anaesthesia and N2O
Nitrous oxide flow should be switched off 10 mins prior to the volatile agent and patient disconnection because:
Due to the insolubility of N2O, any taken up by tissues/blood quickly comes out of solution and enters the alveoli, diluting out the other gases present, including O2. This is called diffusion hypotoxia.
62
What are the contra-indications of using muscle relaxants during anaesthesia?
Inability to judge depth of anaesthesia adequately
| Inability to ventilate patients lungs adequately
63
How do peripherally-acting neuromuscular blocking agents work?
Compete with acetylcholine at post-synaptic nicotinic ACh receptors, thus blocking normal neuromuscular transmission
64
What is the difference between depolarising and non-depolarising peripherally-acting neuromuscular blocking agents?
Non-depolarising simply compete with acetylcholine (need to block 75% of receptors).
Depolarising first stimulate post-synaptic receptors, then the 'block' follows as the membrane becomes refractory (only needs to interact with 5-20% of receptors).
65
How can we assess the degree of a neuromuscular block?
Apply an electrical stimulus to a superficial nerve supplying a muscle, whose 'twitch response' we can observe
66
How can you reverse a neuromuscular block?
Use anti-cholinesterases to increase the amount of ACh available in the synaptic cleft
67
Which (unwanted) muscarinic effects do you see with the use of anti-cholinesterases used to reverse neuromuscular blocks?
```
Increased parasympathetic effects:
Bradycardia
Bronchoconstriction
Salivation
Defecation/urination
Miosis (constricted pupils)
```
68
What are the sites of action of injectable induction agents?
GABA-A receptors
| NMDA receptors
69
Ketamine is contra-indicated in cats with which problems and why?
Cats with compromised renal or hepatic function, as ketamine is excreted unchanged in urine
Metabolised in liver
70
Which injectable anaesthetic agent is best for small animal patients with severe CV disease?
Etomidate
71
How can you facilitate emergency airway access?
Urinary catheters through the larynx
Trans-tracheal needle
Tracheostomy
72
Give the effects of anaesthesia on the respiratory system
Central respiratory depressant effect (decreases response of chemoreceptors to increased CO2)
Relaxation of respiratory muscles (diaphragm, intercostal muscles)
Relaxation of pharyngeal/laryngeal muscles (upper airway obstruction, unprotected airways)
Dependant lung atelectasis (collapse) (reduced blood gas exchange)
73
Give some common problems with recovery from surgery
Hypothermia
Hypotension
Hypoxaemia
Emergence delirium
74
What is MAC?
Minimal alveolar concentration
Concentration of the vapour in the lungs required to prevent movement in 50% of subjects in response to surgical (pain) stimulus
Used to compare strengths (potency) of anaesthetic vapours
Lower MAC= more potent
75
What are the consequences of an animal contracting hypothermia after surgery?
Reduced MAC requirement (animal becomes more deeply anaesthetised as it gets colder)
Increased risk of arrhythmias
Delayed recovery
Shivering -> increased O2 consumption (problematic if borderline hypoxic)
Problems with wound healing
76
With regards to MAC, how much is required for suitable analgesia?
1.2-1.5 x MAC
77
What is Pp?
Partial pressure, of an inhalation agent within the brain
78
Regarding inhalation agents, is a high or low blood solubility desirable and why?
Low, as induction and recovery and changes in depth are faster, because an agent with low blood solubility will reach high partial pressures in the blood more quickly.
79
What is SVP?
Saturated vapour pressure
Pressure exerted by the molecules in the vapour phase in equilibrium with the liquid phase at a given temperature (To)
A liquid with a high SVP is more likely to evaporate at a given temperature
80
What is a problem with the bolus approach of TIVA (total intravenous anaesthesia)?
Hard to maintain drug concentration in desired (therapeutic) range and likely to spend more of the time under/ over dosed
81
Compare the pros and cons of continuous infusion vs bolus approach to TIVA
CI does not need repeated catheter/ bung/ 3-way tap handling
CI means can attempt to titrate drugs for level of anaesthesia
CI should mean quicker recovery
BUT
CI takes more time to set up
CI costs more in equipment and often in drugs as often make up more than you need
CI has possibility of severe over-dose if using drip bag and giving set and you are not observant
82
Why should you take care when using N2O in ruminants?
N2O has a low blood solubility, so will readily move out of the blood into gas-filled spaces (rumen)
83
What is the strongest and longest-lasting opioid?
Methadone
84
What is meant by anaesthetic depth?
Degree of CNS depression
85
Why do we monitor the patient during anaesthesia?
To warn us of any problems with the patients well-being
To warn us of any problems with our anaesthetic equipment
To give us a guide to the patients anaesthetic depth
It's a legal requirement
86
What kind of things can we measure to give us an idea of anaesthetic depth of a patient?
Nervous system: palpebral (blink) reflex, jaw tone, limb withdrawal reflexes
CV and resp systems: HR, RR (and pattern/depth), pulse rate, ECG, blood gas analysis, mm colour, CRT, temperature, urine output
Eye position
87
Where can you feel for a pulse in an anaesthetised animal?
Femoral pulses
Carpal arch pulses (below carpus, back of leg, just below 'stopper pad')
Dorsal pedal (or metatarsal) pulses (below hock)
Lingual pulse (underside of tongue)
88
White/pale mucous membranes indicate what?
Anaemia
| Peripheral circulation is constricted (eg after alpha 2 agonists)
89
Blue/ grey/ purple mucous membranes indicate what?
Struggling of oxygenate the blood
| Problem with resp or cv system
90
What is capnography?
The facility to measure the amount of CO2 in the gases breathed in and out of a patient
91
Give some reasons why inspired CO2 may be higher than zero
The O2 flow is not fast enough to flush exhaled CO2 from the system (non-rebreathing)
Soda lime is exhausted (rebreathing)
The valves in the anaesthetic breathing system are not functioning correctly, and the animal is re-inhaling exhaled gases
92
What is the 'end-tidal' breath?
The last part of the exhaled breath
| Contains carbon dioxide (and less O2)
93
Chronic pain is defined as pain that persists for how long?
Beyond expected time frame (over 3-6 months)
94
What is neuroplasticity?
Functional and/ or anatomical adaptation of the nervous system in response to environmental and physiological processes
95
What is hyperalgesia?
Exaggerated response to a normally painful stimulus
96
What is allodynia?
Normally innocuous stimulus perceives as painful
97
What is multimodal analgesia?
Analgesia which affects as many of the Nociception pathway stages as possible eg transduction, transmission, modulation, perception
98
What is transduction?
Conversion of applied stimulus (eg thermal, mechanical) into an electrical signal (action potential) by activation of nerve end receptors
99
How do primary hyperalgesia and allodynia occur?
Inflammatory mediators and products of cell damage lower nociceptor threshold and recruit silent nociceptors
100
Describe the 'Gate Control' theory of pain
Stimulation by a non-noxious input will suppress pain
Input from Aδ or C fibres inhibits the inhibitory interneuron, and thus increases the chances that the projection neuron will fire -> pain
Input from Aβ fibres activates the inhibitory interneuron, and so suppress the projection neuron -> no pain
101
What do all alpha-2 agonists have in common?
All give analgesia, sedation and muscle relaxation
| However, all affect GI motility and have profound CV side effects
102
What types of fluid loss are there?
Pure water: dehydration
Water and electrolytes: diuresis, vomiting, diarrhoea
Water, electrolytes and protein: transudates, exudates, effusions, severe enteritis, protein-losing enteropathy, protein-losing nephropathy
Blood: haemorrhage
103
Why will an animal always be hypovolaemic if its dehydrated?
Deficit of water meaning they've lost water from all body compartments, including intravascular compartment
104
Which anaesthetic systems can be used for patients under 10kg?
Ayre's T piece
Mapleson D
Mini parallel lack
(all non-rebreathing)
105
Which require a higher gas flow: rebreathing or non-rebreathing systems?
Non-rebreathing
106
Rebreathing systems are used for patients of which weight?
Over 10kg (higher resistance in circuit)
107
How does ACP affect vessels?
Causes vasodilation
108
How do alpha 2's affect vessels?
Cause vasoconstriction
109
What is the onset for ACP?
| What is the duration of action?
Onset: 30 mins
Duration: 4-8 hours
110
Why should you be careful using ACP in anaemic pets?
Can reduce PCV by up to 50% (via vasodilation)
111
Give the effects of ACP
Vasodilator
Unreliable sedation
No analgesia
Can lower seizure threshold so be careful in epileptic patients
Anti-arrhythmic
Can be associated with syncope with high vagal tone and bradycardia (Boxers)
112
Give the effects of alpha 2's
```
CV effects
Reliable sedation
Analgesia
Initial peripheral vasoconstriction
Reflex bradycardia
Decreased RR
Decreased BP to just below normal
Muscle relaxation
```
113
Give the effects of benzodiazepines
Not licensed for veterinary use
May cause excitement rather than sedation
Anti-convulsant
Often used at induction rather than sedation
Minimal CVS and resp depression (so good for neonates)
114
Give some effects of opiods
Give some sedation
Methadone provides the most analgesia, then buprenorphine, then butorphanol
Minimal CVS depression
115
Give some effects of ketamine
More often used as an induction agent
Can be used to enhance sedation of other drugs
Increases muscle tone
Analgesia
116
Why should you not use diazepam in adult horses?
Muscle relaxation produced can cause excitement and panic reactions
Doesn't provide analgesia
117
Does informed consent have to be in writing?
No
118
Which of the 3 gives the most muscle relaxation in horses: xylazine, romifidine, detomidine
Xylazine > detomidine > romifidine
119
Of the alpha 2 agonists used in horses, which is the only one licensed for IM use?
Detomididne (is also the most potent)
120
Magill and Lack breathing systems are suitable for patients of what weight?
10-50kg
121
Bain breathing systems are suitable for patients of what weight?
10-25kg
122
T pieces breathing systems including Mapleson D are suitable for patients of what weight?
<10kg
123
What are the 2 main types of rebreathing systems?
To and fro
| Circle
124
How do peripherally-acting neuromuscular blocking agents work?
Compete with acetylycholine at post-synaptic Nicotinic
| ACh receptors -> block normal neuromuscular transmission
125
Name 2 barbiturate induction agents
Pentobarbital
| Thiopental
126
How does thiopental affect the CV system?
Arrhythmogenic
Negative inotrope
Vasodilation -> hypotension
Resp depression
127
Is thiopental analgesic?
No
128
How is thiopental administered?
iv
129
When is thiopental used?
Top-up boluses
Induction
(Horses)
130
How does alfaxalone affect the CV system?
Vasodilation
Reflex tachycardia
Respiratory and CV depression but not as pronounced as propofol
131
Does alfaxalone provide analgesia?
No
132
How is alfaxalone administered?
iv or im
133
When is alfaxalone used?
Induction and maintenance of anaesthesia in small animals
| Sedation
134
How does propofol affect the CV system?
Mild negative inotrope
Vasodilation (no reflex tachycardia)
Hypotension
Depression, apnoea
135
Is propofol analgesic?
No
136
How is propofol administered?
iv
137
How does ketamine affect the CV system?
Increased HR, CO, BP
| Minimal resp depresion
138
Is ketamine analgesic?
Yes
139
Does ketamine provide good muscle relaxation?
No -> administer with benzodiazepines
140
How is ketamine administered?
iv or im (painful)
141
When is ketamine used?
Induction of large and small animals
Co-induction agent in small animals
To provide analgesia intra and post-operatively
142
How can you confirm an ET tube is in the correct place?
```
Direct visualisation with laryngoscope
Simultaneous movements of thorax and rebreathing bag
Capnograph -> detects exhaled CO2
Detection of air coming out of ET tube
Neck palpation
```
143
How can you provide emergency airway access?
Urinary catheter through larynx
Trans-tracheal needle
Tracheostomy
144
Give the effects of anaesthesia on the respiratory system
Central respiratory depression effect
Relaxation of respiratory muscles
Relaxation of pharyngeal/laryngeal muscles
Dependant lung atelectasis
145
Give some negative effects of mechanical ventilation during an anaesthetic
Uses positive intrathoracic pressure during inspiration -> decreased venous return to the heart -> decreased CO
May cause lung trauma
Activates RAAS-> increased ADH production -> fluid retention
146
Sevoflurane is licensed in which species?
Dogs
147
Give the effects of isoflurane
Respiratory depression
Potent vasodilation
No analgesia
Pungent
148
Give the effects of sevoflurane
```
Quick induction and recovery
Not pungent
Less respiratory depression than isoflurane
Vasodilation
No analgesia
```
149
Which is the only inhalation agent to provide analgesia?
Nitrous oxide
150
Why is total intravenous anaesthesia normally reserved for shorter procedures?
Due to cumulative effects of all injectable agents
151
How far should you insert an oesophageal stethoscope?
Inserted down oesophagus until level with the heart
152
How big should the cuff be when measuring indirect blood pressure?
40% of circumference of the limb
153
What is the gold standard method for measuring blood pressure?
```
Direct arterial blood pressure
Dorsal metatarsal artery (dogs, cats)
Facial artery (horses)
```
154
What do you do if a dog or cat is hypotensive during surgery?
Reduce anaesthetic depth
Fluids
Positive inotrope
155
What do you do if a horse is hypotensive during surgery?
```
Reduce anaesthetic depth if possible
Fluids
Assess ventilation
Alter body position if possible
Check acid-base status
Positive inotrope
```
156
How do you measure central venous pressure?
Jugular catheter
| Tip of the catheter lies in the right atrium
157
What does it mean if end-tidal Co2 is too high (>60mmHg) or too low (<20mmHg)?
```
Too high (>60mmHg): patient is hypoventilating
Too low (<20mmGh): patient is hyperventilating
```
158
What do you do if a dog or cat is hypoventilating during surgery?
Decrease depth of anaesthesia
Start IPPV
May be endobronchial intubation
159
What do you do if a capnograph shows signs of rebreathing?
Increase FGF
Change the soda lime cannister
Check the valve
160
What is the ideal value for SpO2 on a pulse oximeter?
>98%
161
Which is the only local anaesthetic licensed for use in food-producing animals?
Procaine
162
When would you give systemic lidocaine?
Ventricular arrhythmias
163
Which is the most potent local anaesthetic agent?
Bupivacaine (but most cardiotoxic)
164
What is the onset of action of bupivacaine?
30 mins
165
What is the onset of action of mepivacaine?
10 mins
166
Order the following local anaesthetic agents in terms of their duration of action, starting with the shortest:
Procaine, bupivacaine, lidocaine, mepivacaine
Procaine (60 mins) < lidocaine (1.5 hrs) < mepivacaine (2 hrs) < bupivacaine (4 hrs)
167
What are the 4 dental local blocks?
Maxillary (blocks all upper teeth)
Infraorbital (blocks rostral to 3rd premolar; upper)
Mandibular (blocks all lower teeth)
Mental (blocks rostral to 1st premolar; lower)
168
Where do you block before an enucleation?
Ophthalmic nerve
| Techniques: retrobulbar, modified Peterson's block (behind eye)
169
Which nerves do you block when doing an auricular block?
Auriculotemporal nerve
| Great auricular nerve
170
Which nerves does a RUMM block block?
Radial, ulnar, medial, musculocutaneous
| Blocks distal to (but not including) the elbow
171
Which local anaesthetic block would you use if you wanted to block the elbow?
Axillary brachial plexus block
172
What is a bier block?
```
Intravenous regional block
Used for eg limb/digit amputation
Blocks limb distal to a tourniquet
Lidocaine only
Anaesthesia lasts until tourniquet is released
```
173
How long should you keep a tourniquet on for?
2 hours max
174
Give some possible complications of a Bier block
```
Lidocaine toxicity (CNS and CV effects)
Ischaemia if tourniquet left on for too long
```
175
Where is an epidural carried out in a dog or cat?
Between L7 and S1
176
What does an epidural block in a dog or cat?
Both HLs and caudal abdomen (up to umbilicus)
177
When is an epidural contra-indicated?
Skin infections (could spread to spine)
Coagulopathies (haemorrhage -> spinal cord compression)
Neuro dz
Abnormal anatomy eg pelvic fracture
