Anaesthesia (SA11) Flashcards

1
Q

What are the 3 main routes anaesthesia drugs are administered?

A
  • Intravenous
  • Intramuscular
  • Inhalation
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2
Q

What does the sympathetic nervous system do?

A
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3
Q

What does the parasympathetic nervous system do?

A
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4
Q

What is hyvagal tone?

A

Parasympathetic nervous system more dominant, seen in brachycephalics

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5
Q

What order will inspired air pass through the respiratory system?

A
  • Nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli
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6
Q

What controls the respiratory cycle?

A
  • Chemoreceptors detect changes in O2 and CO2
  • ## High CO2 lowers blood pH
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7
Q

Hypoxaemia

A
  • Low level of oxygen in blood
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8
Q

Hypoxia

A
  • Low oxygen in certain area
  • E.G. tissue hypoxia
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9
Q

What is critical oxygen tension level?

A
  • Oxygen level required for metabolic consumption to prevent tissue hypoxia
  • 2-7ml/kg/minute for dogs and cats
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10
Q

What is respiratory acidosis?

A
  • High levels of CO2
  • High levels of carbonic acid
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11
Q

What is respiratory alkalosis?

A
  • High levels of O2
  • Low levels of CO2
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12
Q

What is hypercapnia?

A

Raised ETCO2

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13
Q

What is hypocapnia?

A

Low ETCO2

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14
Q

What is the normal CO2 level in patients?

A

35 - 45 mmHg

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15
Q

What causes hypercapnia?

A

Hypoventilation

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16
Q

What is the cardiac output formula?

A

Heart rate x stroke volume

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17
Q

What is the blood pressure formula?

A

Cardiac output x systemic vascular resistance

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18
Q

What is systemic vascular resistance?

A

Degree of vasocontriction/dilation

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19
Q

What is the herring breuer reflex do?

A
  • Avoid over inflation of lungs
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20
Q

What is anaesthesia

A

A controlled temporary loss of sensation or awareness for medical purposes

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21
Q

What are the 2 types of anaesthesia?

A
  • General
  • Local
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22
Q

What is general anaesthetic?

A

Reversible immobile state that induces amnesia

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23
Q

What is local anaesthetic?

A

Application of anaesthetic to specific area of the body

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24
Q

Why is anaesthesia needed?

A
  • Welfare reasons
  • Legal obligations
  • Facilitate surgery - immobilise and muscle relaxation
  • To control disease - seizures
  • Euthanasia purposes
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25
Q

What is the order of signs in local anaesthetic overdose?

A

GI signs
Nervous system signs
Cardiac signs

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26
Q

What are the 3 local anaesthetic routes?

A
  • Topical
  • Infiltration
  • Regional
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27
Q

What is infiltration local anaesthesia?

A
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28
Q

What is regional anaesthesia?

A
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29
Q

Tachycardia

A

Increased heart rate

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30
Q

Bradycardia

A

Decreased heart rate

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31
Q

Bradypnoea

A

Decreased respiratory rate

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32
Q

Tachypnoea

A

Increased respiratory rate

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33
Q

Apnoea

A

Lack of breathing

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34
Q

Hypotension

A

Decreased blood pressure

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35
Q

Hypertension

A

Increased blood pressure

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36
Q

Hypovolaemia

A

Decreased blood volume

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37
Q

Dog heart rate

A

70 - 140 bpm

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38
Q

Cat heart rate

A

100 - 200 bpm

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39
Q

Dog respiratory rate

A

10 - 30 bpm

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40
Q

Cat respiratory rate

A

20 - 30 bpm

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41
Q

Tidal volume

A

Volume of gas exhaled in one breath
- BW x 10 / 15mls
- <10kg = 15mls / kg
- >10kg = 10mls / kg

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42
Q

Minute volume

A

Volume of gas exhaled in one minute
- Tidal volume x respiratory rate

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43
Q

Residual volume

A

Volume of air left in lung after forced respiration
- Prevents collapse of respiratory collapse

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44
Q

Atelectasis

A

Collapsed lung or lobe
- Alveoli deflate and become filled with fluid

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45
Q

Dead space

A

Air that does not reach alveoli so is not involved in gaseous exchange

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46
Q

Cardiac arrhythmia

A

Abnormal heart rhythm

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47
Q

Sinus arrhythmia

A

Heart rate increase and slow with respiration
Normal in healthy dogs

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48
Q

Pulse deficit

A

Heart rate and pulse rate don’t match
- Usually lower pulse rate
- Indicative of sever cardiac problems

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49
Q

Vagal tone

A

Activity of vagus nerve affecting heart rate and vasoconstriction/dilation
- Increased vagal tone = lower heart rate
- Increased vagal tone common in brachys
- IV prone to very low heart rate under GA

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50
Q

Syncope

A

Fainting due to sudden drop in heart rate and blood pressure
- Vagal response
- Common in boxers

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51
Q

Inhalation agents

A

Produce anaesthesia by inhalation
- Liquids or gases

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52
Q

Volatile anaesthetic agents (VAA)

A

Liquids at room temperature
- Require conversion to vapour
- Isoflorane

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53
Q

Anaesthetic sparing

A

Using local and analgesia to reduce required anaesthetic depth for surgical procedures

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54
Q

Second gas effect

A

Use of nitrous oxide gas as well as volatile agent
- Increases uptake rate of volatile agent

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55
Q

Minimum alveolar concentration

A

MAC
Min concentration of inhaled anaesthetic when 50% of patients will not respond to stimulus

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56
Q

What is premedication?

A
  • Part of all anaesthetic protocols
  • Differ dependent on patient and surgery
  • Contribute to triad of anaesthesia
  • Can produce very different effects
  • Important to know and understand effects to properly monitor
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57
Q

What are the aims of premedication?

A
  • Calm patient
  • Reduce stress
  • Reduce anaesthetic drugs needed
  • Contribute to balanced anaesthesia
  • Provide analgesia
  • Smooth recovery
  • Reduce side effects from anaesthetic drugs
  • Reduce autonomic side effects
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58
Q

Why is it important for premedications to calm the patient and reduce stress?

A
  • Reduce struggle so reduce adrenaline
  • Can effect heart
  • Some anaesthetic drugs sensitise heart to adrenaline and lead to higher risk of arrhythmias
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59
Q

Why is it important for premedications to reduce autonomic side effects?

A
  • Parasympathetic effects like salivation or bradycardia
  • Some agents are added to prevent these
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60
Q

Why is it important for premedications to reduce side effects from other anaesthetic medications?

A
  • Nausea is common side effect
  • Some premeds have anti-emetic properties
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61
Q

What factors need to be considered when selecting premedication protocols for patients?

A
  • Species and breed; considerations, licenses
  • Temperament; route of administration
  • Underlying disease/clinical history/current medication/previous reactions
  • Age; geriatric = disease more likely
  • Lab results; organ dysfunction, excretion route
  • Type of surgery; how painful? muscle relaxation
  • Duration of surgery; how long need to last for
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62
Q

What types of drugs are used in premedications?

A

Sedation
Analgesia
Anti-muscarinics

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63
Q

What factors may change route of induction?

A
  • Medication
  • Temperament
  • Speed of onset needed
    Must give sufficient time to see full benefits
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64
Q

What are the main groups of sedative agents?

A
  • Phenothiazines
  • Benzodiazepnes
  • Alpha 2 agents
  • Dissociatives
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65
Q

What is the only licensed veterinary phenothiazine?

A

Acepromazine (ACP)
- Widely used for premed
- Synergistic with opioids
- Lasts 6 hours; will smooth recovery
- Slower onset
- Can be given IV, IM and SC
- More effective if animals is relaxed
- Not reliable for aggressive animals and cats
- Neuroplept effect in higher doses - heavy sedation

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66
Q

What are the physiological effects of acepromazine?

A
  • Prevent adrenaline induced arrhythmias
  • Anti-emetic effect
  • Antihistamine
  • Vasodilation leading to hypotension
  • Vasodilation + hypothalamus effects = hypothermia
  • Boxers have known sensitivity; may collapse
  • Decreased seizure threshold
  • Decreased PCV due to splenic sequestrum; avoid in anaemic patients.
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67
Q

What are the benzodiazepines that are widely used in veterinary medicine?

A
  • Diazepam; licensed vet product (Ziapam)
  • Midazolam; unlicensed (Hypnovel)
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68
Q

What is apneustic breathing?

A

Expiratory pause is normal
Apneustic is an inspiratory pause

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69
Q

What are the 3 different induction techniques?

A
  • Inhalation
  • IV
  • IM
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70
Q

What factors may influence the choice of anaesthetic agent?

A
  • Species
  • Temperament
  • Protocol and drugs
  • Age of patient
71
Q

What are the methods of inhalant induction?

A
  • Chamber
  • Mask
72
Q

What are the disadvantages of inhalant induction?

A
  • Stressful
  • Restraint difficult when masking
  • Health and safety with leakage
  • May breath hold or salivate excessively
73
Q

What must injectable anaesthetic agents be to work?

A

Lipophilic so they are able to cross the blood brain barrier

74
Q

What is alfaxalone

A

Steroid anaesthetic agent

75
Q

What species is alfaxalone licensed for?

A

Cats
Dogs
Rabbits

76
Q

How can alfaxalone be administered?

A

Licensed IV
Can give IM

77
Q

What is propofol?

A

Phenolic compound

78
Q

What is thiopentone?

A

Barbiturate anaesthetic compound

79
Q

What are the contraindications for Thipentone?

A
  • Sight hounds as less fat
  • Splenectomy as enlarged spleen
  • Skin sloughing if out of IV due to alkaline
80
Q

What is ketamine?

A

Dissociative

81
Q

What are the 4 main ways to maintain anaesthesia?

A
  • Inhalant gas
  • Total intravenous anaesthesia (TIVA)
  • Partial intravenous anaesthesia (PIVA)
  • Injectable agents intramuscularly
82
Q

What are the advantages of inhalant anaesthesia?

A
  • Usually protected airway, oxygen easily supplied
  • Depth easy to control
  • Recovery not dependent on drug metabolism as mainly excreted via exhalation
  • Rapid recovery times
83
Q

What are the disadvantages of inhalant anaesthesia?

A
  • Anaesthetic machine and trained staff required
  • Scavenging system required
  • Atmospheric pollution during recovery
  • Inhalant gasses are greenhouse gasses so contribute to damage of ozone layer
84
Q

Volatile agents

A
  • Liquid at room temperature, vaporised
  • Isoflurane and Sevoflurane
  • Carried in another gas; oxygen, nitrous oxide or medical air - vapour at room temp so in gas canisters
85
Q

Delivery of inhalant agents

A
  • Via breathing system
  • ## Passes through lungs, alveolar membrane and into blood stream
86
Q

MAC

A
  • Minimum alveolar concentration of inhaled anaesthetic
  • Potency of agent
  • Lower MAC = Less concentration of agent required
  • Impacted by many factors; premeds used
87
Q

What is the MAC value of Halothane?

A

0.75

88
Q

What is the MAC value of Isoflurane?

A

1.15

89
Q

What is the MAC value of Sevoflurane?

A

2.05

90
Q

What is the MAC value of Desflurane?

A

5-10

91
Q

Solubility in blood of inhalant agents

A
  • Determines speed of induction and recovery
  • Greater solubility, slower onset of action
  • Newer agents less soluble for quicker induction and recovery
92
Q

Another word for solubility of drugs?

A

Blood gas partition co-efficient

93
Q

Factors effecting gaseous recovery

A
  • Concentration of anaesthetic gas
  • Alveolar ventilation, quality breathing
  • Agent solubility in blood
  • Cardiac output
94
Q

Nitrous oxide

A
  • Carrier gas, vapor at room temp
  • Supplied in blue canisters
  • Used along side oxygen
  • Must not exceed 70% of fresh gas flow
  • Less soluble, wears off very quickly
  • Effective analgesic
  • Patient must receive 100% oxygen for 5-10 minutes after turning off to avoid diffusion hypoxia.
95
Q

What is diffusion hypoxia?

A
96
Q

Contraindications for using nitrous oxide

A
  • Will diffuse into and expand gas filled cavities
  • Can expand ET tube cuff
  • Avoid in patients with cardiovascular or respiratory disease
  • Not used in rabbits as gassy hind gut fermenters
97
Q

Second gas effect

A
  • Using nitrous oxide to speed up induction
  • Nitrous has low solubility so moves rapidly from lungs to bloodstream
  • Will take volatile agent during rapid diffusion
  • Will speed induction
98
Q

TIVA

A
  • Injectable IV agents incrementally or constant rate
  • Can only be preservative free propofol
  • Can only be 30 minutes for cats
  • Propofol or alfaxan
99
Q

Disadvantages of TIVA

A
  • Some drugs may accumulate and prolong recovery
  • Difficult to maintain constant depth via incremental
  • CRI requires syringe driver for accuracy
  • -
100
Q

PIVA

A
  • Combining inhalant and IV agent for maintenance
  • Provides very balanced anaesthesia
  • Protocols may be complicated so experiences anaesthetist required
101
Q

Patient positioning under anaesthetc

A
  • Patients in dorsal recumbency may have impaired respiratory function due to pressure on diaphragm
  • Plastic troughs should not be too tight as may interfere with thoracic movement
  • Tying forelimbs tightly may interfere with thoracic movement
  • Patency of airway to ET tube may be compromised especially in ventral recumbency
102
Q

What is pain?

A
  • Sensory and emotional experience
  • Associated with actual or potential tissue damage
  • Caused by noxious stimuli
103
Q

What is a noxious stimulus?

A
  • Damaging to tissues
  • Detected by nociceptors
  • Then activates nociceptive pathways
  • Transmitted by nerves to spine and up to brain
  • Thermal, mechanical or chemical
  • Usually results in pain
104
Q

Nociception is

A

Perception of pain

105
Q

Why is pain detrimental?

A
  • Causes fear, anxiety and distress
  • Delays wound healing
  • Predisposes to intestinal ileus
  • Impairs respiration affecting acid base balance
  • Wound interference and self trauma
  • Prolongs recovery
  • Reduces food intake
  • Affects cardiovascular function due to stimulation of sympathetic nervous system = increased HR and cause vasoconstriction
106
Q

What are the 3 pain catagories?

A
  • Physiological pain
  • Inflammatory pain
  • Neuropathic pain
107
Q

What is physiological pain?

A
  • Early warning device
  • Alert to possibility of tissue damage
  • Pain stops when stimulus stops
108
Q

How can muscle relaxation be achieved?

A
  • Selection of premed agents
  • GA; high concentrations needed, not advised
  • Regional anaesthesia/analgesia
  • Neuromuscular blocking agents (NMBA)
109
Q

What are some indications for use of neuromuscular blocking agents?

A
  • Ocular surgery; prevent downward rotation of eye or unpredictable movements
  • ## Facilitate IPPV; prevent natural override of ventilation
110
Q

What are the 2 types of neuromuscular blocking agents?

A

DEPOLARISING
- Suxamethonium
- Can’t be reversed
NON-DEPOLARISING
- Atracurium, Pancuronium, Necuromium
- Can be topped up without prolonged effect
- Can be reversed

111
Q

What are the functions of anaesthetic breathing systems?

A
  • Transfer gases from GA machine to patient
  • Remove C02 exhaled by the patient
  • Deliver artificial breaths (IPPV)
  • Measure airway pressure, gas volumes and composition
  • Scavenge waste gasses
112
Q

Rebreathing

A
  • Inhalation of previously breathed gases that have taken part in gaseous exchange
113
Q

Reservoir bag

A
  • Open ended or closed bag attached to the breathing system
114
Q

What is IPPV?

A

Intermittent positive pressure ventilation

115
Q

Limbs of circuit

A
  • Tube of breathing system where gases are carried
116
Q

Uni-directional valves

A
  • One way valves
  • Ensure gas only flows in one direction
117
Q

APL valve

A
  • Adjustable pressure limiting valve (Pop off)
  • Controls amount of gas contained within bag and how much escapes through scavenging
  • Usually a plastic disc on spring
  • Depressed when set pressure is exerted to allow gasses to escape
  • Safety system but pressure needed quite high so patient probably have suffered some barotrauma
  • Valve can close and open to control pressure
118
Q

Fresh gas inlet

A
  • Point where gas enters breathing system from common gas outlet on machine
119
Q

Coaxial system

A
  • Inspiratory and expiratory tubes within one another
120
Q

Parallel system

A
  • Inspiratory and exspiratory limbs run side by side
121
Q

Lung compliance

A
  • How well lungs stretch to accommodate a change in volume in relation to pressure applied
122
Q

Circuit resistance

A
  • Pressure drop when breathing through a tube
  • Requires more effort
  • Is increased the longer the tube is
  • Is increased the more turbulent the airflow
  • Smooth bore tubes lower resistance
  • Can be bought for most circuits
  • Smaller patients respiratory function will be effected more by higher resistance due to small tidal volume
123
Q

Mapleson classification

A
  • Way of classifying non rebreathing circuits
124
Q

Advantages of non-rebreathing systems

A
  • Inhalant gas can be adjusted rapidly
  • Minimal circuit resistance
  • Easy to use
  • Cheap to purchase
  • Safe and optimal use of N20
125
Q

Disadvantages of non-rebreathing systems

A
  • High gas flow rates
  • Increase environmental contamination
  • Higher gas and volatile agent costs
  • Potential for rebreathing is tachypnoea leads to insufficient flow rate
  • Heat loss through respiratory tract
126
Q

What measures can be put in place to ensure rebreathing does not occur while using non-rebreathing circuits

A
  • Calculate fresh gas flow rate for every patient
  • Adjust fresh gas flow if RR increases during GA
  • Calculate with correct circuit factor
  • Consider use of capnography
127
Q

Calculating fresh gas flow rates

A
  • Tidal volume = 10-15ml/kg
  • 10ml for over 10kg
  • 15ml for under 10 kg
  • Deep chested may require 12-15mls/kg
  • Minute volume = Tidal volume x RR
  • Fresh gas flow = MV x circuit factor
128
Q

What is the maximum ratio for combination nitrous oxide and oxygen for fresh gas fow?

A

2:1

129
Q

Considerations when selecting a circuit

A
  • Patient weight (choose for lean weight)
  • Will IPPV be needed?
  • Drag on patient from circuit? (pull on tube)
  • Gas flow rate - Higher - hypothermia and costs
130
Q

Ayres T-Piece

A
131
Q

What are rebreathing systems?

A
  • Allows gasses previously exhaled to be reused
  • Use C02 absorbent
132
Q

What are the 2 main rebreathing systems?

A
  • Circle
  • To and fro
133
Q

What are the advantages of rebreathing systems?

A
  • Low gas flow rates; reduce cost and environmental contamination
  • Reduced heat loss by reusing warm air
134
Q

What are the disadvantages of rebreathing systems?

A
  • Altering concentration of VA takes time unless system completely refilled
  • C02 absorbent and valves increase resistance
  • Requires understanding of use
  • Maintenance; C02 absorbent changing
  • Expensive to purchase
135
Q

What is the most common rebreathing system in veterinary industry?

A
  • Circle
  • Models vary; different canisters and tubes
136
Q

What size patient can use a circle system?

A
  • Most suitable for over 10kg
  • Smaller models available
137
Q

What valves do circle systems contain?

A
  • Unidirectional valves
  • (Reubens valves)
138
Q

What are the advantages of the circle system?

A
  • Reduce fresh gas flow/VA costs
  • Less environmental contamination
  • Reduced heat loss from patient
  • Inspired gases moistened
  • Ideal for IPPV
139
Q

What are the disadvantages of the circle system?

A
  • Canisters need refilling; fiddly, hard to clean
  • Canisters can be source of leak; inspect regularly
  • Cost of C02 absorbent
  • Knowledge + time needed for maintenance
  • Will harbour moisture; needs to dry
  • C02 absorbent creates resistance; not suitable for smaller patients
  • Expensive to purchase
  • May exacerbate hyperthermia in large patients
  • Not advised to use nitrous oxide
140
Q

Why shouldn’t nitrous oxide be used with circle circuits?

A
  • Unless experienced anaesthetist with appropriate monitoring equipment
  • Nitrous will accumulate in system
  • Leads to higher concentrations over time
141
Q

How does a circle work?

A
  • At start, period of denitrogenation must take place
  • May be operated as closed/semi closed
  • Contains one way valves to ensure direction
  • Patient breaths in from inspiratory limb
  • One-way valves control exhaled gases
  • Gases flow into reservoir bag
  • Then through soda lime canister
  • Soda lime converts CO2 to O2 to be reused
  • Levels of VA remain same as exhaled from body
  • Small amounts of fresh gas added to system
142
Q

What is denitrogenation?

A
  • Room air contains high levels of nitrogen
  • First anaesthetised, exhale nitrogen
  • If builds up in system, gas mixture hypoxaemic
  • So higher gas flow used for first 15-20 minutes
  • Usually 100ml/kg/min (Open, semi-open)
  • Then gas flow dropped as semi-closed or closed
143
Q

What does a ‘closed system’ mean in reference to circle circuits?

A
  • Supply metabolic oxygen requirement only
  • Operate with valve closed
144
Q

Why are ‘closed systems’ in reference to circle circuits not recommended?

A
  • Metabolic oxygen consumption varies (2-10ml/kg)
  • Flowmeters don’t allow accurate delivery of low flow rates
  • Vaporisers not calibrated for very low flow rates
  • Accurate monitoring to ensure no CO2 rebreathing
  • Reliant on function of CO2 absorbent
145
Q

What is a semi-closed system in reference to circle circuits?

A
  • Operate with valve semi-open
  • 1 litre/min fresh gas flow after denitrogenation
  • Lower FGF rates may be used where adequate CO2 level monitoring in place
146
Q

Why should patients be intubated during anaesthesia?

A
  • Protect airway
  • Maintain patent airway
  • Prevent soft tissue obstruction
  • Prevent secretion obstruction
147
Q

Why are some patients not intubated?

A
  • Depends on size of patient
  • <2kg difficult to tube
  • Small diameter tube cause more resistance
  • Some species can not easily be intubated
148
Q

What are the type of endotracheal tubes?

A
  • Red rubber (Magill)
  • Polyvinyl chloride (PVC)
  • Silicone
  • Cuffed
  • Uncuffed
  • Re-enforced
149
Q

What are the 2 main types of cuffs?

A

HIGH PRESSURE, LOW VOLUME
- More secure protection of airway
- More risk of pressure
LOW PRESSURE, HIGH VOLUME
- Pressure over larger area
- Airway protection not as secure

150
Q

What tubes are usually chosen for dogs?

A
  • Cuffed tubes
151
Q

Why are cuffed tubes not ideal for use in cats?

A
  • Very prone to tracheal necrosis
  • Cuffed only used in high aspiration risk or during ventilation
  • Great care must be taken with cuffed tubes
152
Q

What is an alternative to a cuffed tube when preventing aspiration?

A
  • Throat packs
  • Useful in dentals
153
Q

What are the advantages and disadvantages of red rubber (Magill) tubes?

A

ADVANTAGES
- Re-useable
- Wide range of sizes
- Can be autoclaved
- Easy to intubate as pre-moulded
DISADVANTAGE
- Expensive, especially larger sizes
- Perish with time
- Kink easily
- Cannot see internal contamination
- Cuff valve not self sealing
- Only low volume, high pressure

154
Q

What are the advantages and disadvantages of of PVC tubes?

A

ADVANTAGES
- Cheap
- Designed to be disposable, can reuse
- Malleable when warm
- Fairly kink resistance
- Both low vol, high press + high vol, low press
- Easier to see internal contamination
- Cuffs valved
- Some have murphy’s eye
DISADVANTAGES
- Designed to be disposable
- Cannot be repaired
- Limited sizes - very large unavailable
- Cannot be autoclaved
- Connectors can loosen when tube warms

155
Q

What are the advantages and disadvantages of silicone tubes?

A

ADVANTAGES
- Can be repaired
- Can be autoclaved
- Malleable when warm
- Fairly kink resistant
- Cuffs are valved
- Wide range of sizes
- Can just see internal contamination
- Some have Murphy’s eye
DISADVANTAGES
- Expensive
- May require stylet for intubation as no moulded curve

156
Q

What are the advantages and disadvantages of armoured tubes?

A

ADVANTAGES
- Same as PVC, usually PVC material
- Internal wire coil to prevent kinking
DISADVANTAGES
- Very expensive
- If bitten down on will permanently occlude
- Do not spring back due to wire content

157
Q

Bonus endotracheal tube facts

A
  • Some have radiopaque line
  • Tube size is internal diameter in mm
  • Most tubes have length markings
158
Q

What should be considered when choosing sizes of endotracheal tubes?

A
  • Should be comfortable fit to avoid excessive cuff inflation
  • Tube not too long; bronchial intubation may occur, increased dead space
  • Tubes should not be too short, easily dislodged
  • Measure from front of incisors to thoracic inlet
  • Always get more than one tube size
  • Brachys have very narrow trachea
159
Q

What checks should be done on endotracheal tubes before intubating patients?

A
  • Visually inspect for damage
  • Check lumen clear, pass tube brush, never blow
  • Check cuffs work, inflate, squeeze, fully deflate
160
Q

What are some aids to intubation?

A
  • Laryngoscope
  • Stylets (can use urinary catheter)
  • Silicone based sprays for lubrication
161
Q

What are the types of laryngoscope?

A
  • Miller blade (curved)
  • Macintosh (straight blade)
  • Other specialist blades available for rabbits etc.
162
Q

How are stylets used to intubate patients?

A
  • Stylet placed and threaded over the top
  • Stylet can make tube rigid
  • Urinary catheter can also be used for this
163
Q

How does lube help with intubating?

A
  • Sterile lube
  • Silicone based sprays
  • Reduce trauma
  • If water-based can dry out, become sticky and block tube
164
Q

What is the correct technique when intubating patients?

A
  • Ideally positioned in sternal
  • Head and neck in straight line
  • Cats should have larynx sprayed with local to prevent larangeal spasm - wait 45 seconds
  • Pull out tongue
  • Depress just in front of epiglottis with laryngoscope
  • Pass tube through glottis, into trachea and insert to correct level
  • Secure in place
  • Attach to breathing circuit
  • Give gentle manual breath to listen for leak
  • Slowly inflate cuff until no leak heard
165
Q

How to confirm correct placement of endotracheal tube once placed?

A
  • Ausculate thorax sides to ensure no bronchial intubation
  • Watch for condensation inside tube
  • Check patient chest and bag movement
  • Monitor capnography for CO2 presence
166
Q

How can the cuff be checked to ensure the correct amount of air has inflated it?

A
  • Care to only inflate enough to prevent leakage
  • Checked by listening when patient is given a manual breath
  • More accurate to check pressure cuff is exerting on tissues
  • Special cuff inflator to show pressure
  • Some have automatic shut off
  • Ideal pressure should be 20-30cmH2O
167
Q

What are the different ways gas can be supplied?

A
  • Cylinder
  • Piped gas system
  • Oxygen generator
168
Q

How are piped gas systems run?

A
  • Large cylinders outside of building
  • Small cylinders can attach directly onto anaesthetic machines
169
Q

How is the pressure of oxygen controlled on cylinders?

A
  • Gas runs through pressure reducing valve (regulator)
  • Reduces pressure to safe level
  • Prevents surges
  • Produces consistent pressure
  • Built into machines that use small cylinders
  • Located at source cylinder in piped systems
170
Q

What is the colour code for oxygen cylinders?

A
  • Black cylinder
  • White shoulders
171
Q

What is the colour code for nitrous oxide cylinders?

A
  • Blue
172
Q

How are cylinder sizes identified?

A
  • Letters
  • Later in alphabet, larger the cylinder
  • Portable cylinders often E or F
  • Piped gas systems J or similar
173
Q
A