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Yr 4 - ACC > Anaesthetics: General Anaesthetic Agents & Induction/Maintenance > Flashcards

Anaesthetics: General Anaesthetic Agents & Induction/Maintenance Flashcards

1
Q

What are the 3 main categories of anaesthesia?

A

1) General: making the patient unconscious

2) Regional: blocking feeling to an isolated area of the body (e.g., a limb)

3) Local

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2
Q

Purpose of fasting before a planned general anaesthetic?

A

Ensure empty stomach –> reduce risk of stomach contents refluxing into oropharynx (throat) –> reduce risk of aspiration into the trachea.

Gastric contents in the lungs creates an aggressive inflammatory response, causing pneumonitis (inflammation of the lung tissue).

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3
Q

When is the risk of aspiration highest during general anaesthesia?

A

Before and during intubation, and when they are extubated.

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4
Q

What does fasting for an operation typically include?

A

1) 6 hours of no food or feeds before the operation

2) 2 hours of no clear fluids (‘nil by mouth’)

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5
Q

What is ‘preoxygenation’ in surgery?

A

Before being put under a general anaesthetic, the patient will have a period of several minutes when they breathe 100% oxygen.

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6
Q

Purpose of preoxygenation prior to general anaesthetic?

A

This gives them a RESERVE of oxygen for the period between when they lose consciousness and are successfully intubated and ventilated (in case the anaesthetist has difficulty establishing the airway).

N.B. This step may need to be skipped when an emergency general anaesthetic is required.

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7
Q

Medications are given before the patient is put under a general anaesthetic.

What may these include?

A

1) Benzodiazepines (e.g. midazolam)

2) Opiates (e.g. fentanyl or alfentanyl)

3) Alpha-2-adrenergic agonists (e.g., clonidine)

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8
Q

Purpose of benzos prior to general anaesthetic?

A

To relax the muscles and reduce anxiety (also causes amnesia)

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9
Q

Purpose of opiates prior to general anaesthetic?

A

to reduce pain and reduce the hypertensive response to the laryngoscope

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10
Q

Purpose of alpha-2-adrenergic agonists prior to general anaesthetic?

A

Can help with sedation and pain

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11
Q

Give an example of an alpha-2-adrenergic agonist used prior to general anaesthetic

A

Clonidine

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12
Q

What is rapid sequence induction/intubation (RSI)?

A

Used to gain control over the airway as quicky and safely as possible where a patient is intubated in an EMERGENCY scenario and detailed pre-planning is not possible.

The procedure is designed to ensure successful intubation with an endotracheal tube as soon as possible after induction (when the patient is unconscious) to protect the airway.

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13
Q

Why is RSI more risky?

A

Ass the patient has often not been fasted (risk of aspiration), and the anaesthetist has not had the chance to plan for individual factors and potential problems (e.g., a difficult airway).

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14
Q

When is RSI used?

A

a) emergency scenario

b) non-emergency scenario where the airway needs to be secured quickly to avoid aspiration e.g. in patients with gastro-oesophageal reflux or pregnancy.

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15
Q

What is the biggest concern during RSI?

A

Aspiration of stomach contents into the lungs.

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16
Q

How can the risk of aspiration be reduced in RSI?

A

1) Position bed so the patient is more upright to reduce reflux of contents up the oesophagus

2) Cricoid pressure (pressing down on the cricoid cartilage in the neck): can compress the oesophagus and prevent the stomach contents from refluxing into the pharynx

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17
Q

What should you be aware of regarding cricoid pressure in RSI?

A

This is somewhat controversial and should only be done by someone trained and experienced.

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18
Q

What is the triad of general anaesthesia?

A

1) Hyponosis

2) Muscle relaxation

3) Analgesia

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19
Q

Purpose of hypnotic agents in anaesthesia?

A

Used to make the patient unconscious.

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20
Q

How are hypnotic agents given?

A

IV or inhaled

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21
Q

What is the most commonly used IV hyponotic agent?

A

Propofol

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22
Q

What is the most commonly used inhaled hypnotic agent?

A

Sevoflurane

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23
Q

Give 4 options for IV hypnotic agents

A

1) Propofol

2) Ketamine

3) Thiopental sodium (less common)

4) Etomidate (rarely used)

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24
Q

Give 4 options for inhaled hypnotic agents

A

1) Sevoflurane

2) Desflurane (less favourable as bad for the environment)

3) Isoflurane (rarely used)

4) Nitrous oxide (combined with other anaesthetic medications – may be used for gas induction in children)

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25
Q

Sevoflurane, desflurane and isoflurane are volatile anaesthetic agents.

What does this mean?

A

Volatile agents are liquid at room temperature and need to be vaporised into a gas to be inhaled.

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26
Q

What device is used for iinhaled volatile agents?

A

Vaporiser devices

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27
Q

How do vaporiser devices work?

A

1) Liquid medication is poured into machine

2) Machine turns it into vapour and mixes it with air in a controlled way

3) During the anaesthesia, the concentration of the vaporised anaesthetic medication can be altered to control the depth of anaesthesia.

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28
Q

How will IV vs inhaled hyponotic agents commonly be used during operations?

Why?

A

IV medication will be used as an induction agent (to induce unconsciousness) –> are infused directly into the blood and so can quickly reach an effective concentration.

Inhaled medications will be used to maintain the general anaesthetic during the operation –> need to diffuse across the lung tissue and into the blood, where it takes a while for them to reach an effective concentration.

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29
Q

What does total IV anaesthesia (TIVA) involve?

A

Involves using an IV medication for induction and maintenance of the general anaesthetic.

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30
Q

What is the most commonly used agent for TIVA?

A

Propofol

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31
Q

Benefit of TIVA over inhaled options?

A

Can give a nicer recovery as they wake up compared with inhaled options.

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32
Q

How is propofol given?

A

IV

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33
Q

What is propofol?

A

A general anaesthetic

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34
Q

Indication for propofol?

A

1) induction agent

2) intensive care for ventilated patients

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35
Q

Mechanism of propofol?

A

1) Decreases the rate of dissociation of GABA from its receptor

2) Which increases the duration of the GABA-activated opening of the chloride channel

3) Leads to hyperpolarisation of cell membranes

4) Increased inhibitory tone in the central nervous system.

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36
Q

2 key adverse effects of propofol?

A

1) Pain on injection

2) Hypotension (marked drop in BP)

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37
Q

Why can propofol cause pain on injection?

A

Due to activation of the pain receptor TRPA1

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38
Q

Who is propofol useful in?

A

Patients with high risk of post-op vomiting –> due to anti-emetic effects.

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39
Q

What is thiopental?

A

a general anaesthetic

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40
Q

How is thiopental given?

A

IV

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41
Q

Mechanism of thiopental?

A

A type of barbiturate.

1) Decreases neuronal activity

2) This decreases cerebral metabolic rate of oxygen consumption

3) This decreases cerebrovascular response to carbon dioxide

4) This decreases intracranial pressure

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42
Q

Main side effect of thiopental?

A

Laryngospasm

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43
Q

Benefit of thiopental?

A

It is very lipid-soluble so affects the brain quickly i.e. mainly used for rapid sequence induction.

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44
Q

How do anaesthetic drugs typically work?

A

1) Bind to GABA receptor to potentiate the action of GABA (a major inhibitory neurotransmitter) –> this leads to the anaesthetic state of unconsciousness, muscle relaxation and analgesia.

2) Also work by opening K+ channels that modulate neuro-excitability –> this reduces membrane excitability.

3) Also inhibit opening of ligand-gated ion channels that allow Na+ to enter the cell.

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45
Q

Why does opening K+ channels cause anaesthetic effect?

A

Reduces membrane excitability –> will lead to more negative resting potential, making it more difficult to start an action potential.

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46
Q

What is etomidate?

A

General anaesthetic

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47
Q

How is etomidate given?

A

IV

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48
Q

Mechanism of etomidate?

A

Potentiates GABA

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49
Q

2 main side effects of etomidate?

A

1) Primary adrenal suppression (2ary to reversibly inhibiting 11β-hydroxylase)

2) Myoclonus

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50
Q

When is etomidate typically used? Why?

A

Typically used in cases of haemodynamic instability –> causes LESS hypotension than propofol and thiopental during induction.

I.e. mainly used in Cardiac patients Induction (Hemodynamic stability).

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51
Q

Mechanism of ketamine?

A

Blocks NMDA receptors (a receptor of glutamate: the primary excitatory neurotransmitter).

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52
Q

2 main adverse effects of ketamine in general anaesthesia?

A

1) disorientation
2) hallucination

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53
Q

Which general anaesthetic acts as a ‘dissociative anaesthetic’?

A

Ketamine

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54
Q

When is ketamine favoured as an anaesthetic? Why?

A

1) In patients with unknown medical history
2) In the treatment of burn victims
3) Trauma

As doesn’t cause a drop in blood pressure or depress breathing and circulation as much as other anesthetics.

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55
Q

Which general anaesthetic has a side effect of laryngospasm?

A

Thiopental

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56
Q

Which general anaesthetic has a side effect of pain on injection?

A

Propofol

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57
Q

Which general anaesthetic has a side effect of 1ary adrenal suppression?

A

Etomidate

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58
Q

Give 3 examples of volatile liquid anaesthetics

A

1) sevoflurane
2) isoflurane
3) desflurane

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59
Q

What are the 3 stages of a general anaesthetic?

A

1) induction

2) maintenance

3) emergency

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60
Q

Before a general anaesthetic, a comprehensive pre-operative assessment should be performed to determine anaesthetic drug choice and technique.

What should this include?

A

1) assessment of comorbidities

2) fasting status

3) airway assessment

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61
Q

What 4 essential steps should occur before the patient is brought to the operating theatre?

A

1) Pre-op visit and airway assessment by anaesthetist

2) Theatre team brief

3) Preparation of airway tray, emergency and induction drugs

4) Ventilator check

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62
Q

Upon entering the anaesthetic room/theatre, the patient will undergo safety checks and have essential monitoring attached.

This can vary according to the procedure, but at a minimum what does it include?

A

1) ECG

2) Blood pressure (NIBP)

3) Capnography

4) Anaesthetic depth monitoring

5) SpO2

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63
Q

What is the most commonly used device for maintaining an open airway during administration of anesthesia?

A

Supraglottic device i.e. laryngeal mask airway (LMA)

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64
Q

What are the 2 types of airway management of general anaesthesia?

A

1) Endotracheal tube (ET tube or ETT)

2) Supraglottic Airway (SGA) (E.g. Laryngeal Mask Airway)

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65
Q

Where is the SGA placed?

A

It is a plastic tube with a large cuff that is placed into the back of the throat and is positioned above the opening to the trachea (windpipe).

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66
Q

2 benefits of SGA over endotracheal tube?

A

1) Lower incidence of sore throat

2) Allows patient to easily breathe on their own

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67
Q

Contraindications to SGA?

A

1) Patients with higher risk of reflux e.g. those who have eaten within the previous 6-8 hours, pregnant women, and diabetic patients whose stomachs do not empty properly

2) Laparoscopic surgery

3) Surgery requiring careful control of breathing – includes brain, cardiac and thoracic/chest procedures

4) Prone positioning (surgery performed with the patient lying on their stomach)

5) Surgery in the nose or mouth

6) Obesity

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68
Q

Why is SGA contraindicated in patients with higher risk of reflux?

A

The SGA sits above the opening to the trachea sogases may also be delivered to the stomach via the oesophagus, particularly if the patient is being ventilated (the anesthesiologist is providing breaths for the patient) via the SGA.

This means that anything that is regurgitated could potential go into the lungs –> risk of aspiration.

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69
Q

Why is SGA contraindicated in prone positioning (surgery performed with the patient lying on their stomach)?

A

makes it very difficult or impossible to adjust or replace the SGA if it gets dislodged.

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70
Q

Why is SGA contraindicated in laparoscopic surgery?

A

the high pressure created in the abdomen makes it difficult to ventilate with the SGA

71
Q

Why is SGA not often used in obesity?

A

1) Increased soft tissue in the airway and neck can make properly placing the SGA more difficult.

2) The added weight of the abdomen can also make ventilation difficult (similar to the pressure created with laparoscopic surgery).

72
Q

What is the most common problem with SGA placement?

What happens if this occurs?

A

That the device does not fit or seal well enough to deliver adequate amounts of anesthetic gases and oxygen.

In this situation, the SGA is removed and an endotracheal tube is placed.

73
Q

What is an endotracheal tube (ETT)?

A

A plastic tube that is inserted into the trachea and allows for a direct route of delivery of oxygen and removal of carbon dioxide from the lungs.

74
Q

What is placement of an ETT referred to as?

A

Intubation

75
Q

During intubation, what is used to displace the tongue and allow visualisation of the vocal cords and airway?

A

A laryngoscope (blade with a light at the end of it)

76
Q

What is the most common complaint following intubation with ETT?

A

Sore throat

77
Q

What are some complications of ETT placement?

A

1) Sore throat

2) Cuts to the lips, tongue, gums, throat

3) Damage to the teeth

4) Hoarseness from temporary or permanent damage to the vocal cords

5) Increased blood pressure or heart rate

6) Asthma exacerbation

7) Brain damage and/or death secondary to inability to intubate

78
Q

As a general rule, what type of airway management is used in patients with any risk of airway soiling (regurgitation, unfasted status) or anticipated difficulty with ventilation?

A

An endotracheal tube (ETT)

79
Q

Give some examples that may cause anticipated difficulty with ventilation?

A

1) obesity
2) lung pathology
3) laparoscopic surgery

80
Q

If a patient is considered at high risk of airway soiling, what can be used?

A

a rapid sequence induction (RSI) technique can be performed

81
Q

What is involved in RSI?

A

A rapid, successive administration of induction and neuromuscular blocking (paralytic/muscle relaxant agents) drugs to achieve a state of unconsciousness and paralysis in the shortest time possible (usually within less than a minute) to secure the airway.

82
Q

Mechanism of sevoflurane (and the volatile liquid anaesthetics)?

A

Exact mechanism of action unknown. May act via a combination of GABAA, glycine and NDMA receptors

83
Q

What are the 3 adverse effects of volatile liquid anaesthetics
(isoflurane, desflurane, sevoflurane)?

A

1) Myocardial depression

2) Malignant hyperthermia

3) Halothane is hepatotoxic (now not commonly used)

84
Q

Why is halothane now not commonly used?

A

Hepatotoxic

85
Q

How are volatile liquid anaesthetics
(isoflurane, desflurane, sevoflurane) administered?

A

Inhaled

86
Q

Indications for volatile liquid anaesthetics
(isoflurane, desflurane, sevoflurane)?

A

Induction and maintenance of general anaesthetics.

87
Q

What is malignant hyperthermia?

A

A potentially fatal reaction to certain general anaesthetic medications, or the muscle relaxant, suxamethonium.

88
Q

What 2 things is malignant hyperthermia triggered by?

A

1) exposure to certain volatile inhalation anaesthetics

2) suxamethonium (the depolarising muscle relaxant)

89
Q

What is the most common cause of malignant hyperthermia?

A

An autosomal dominant mutation in the ryanodine receptor 1.

This results in an abnormality in calcium regulation within muscle cells –> leads to increased calcium levels in the sarcoplasmic reticulum and a consequent increase in metabolic rate.

90
Q

Signs and symptoms of malignant hyperthermia?

A

1) rapid increase in body temp

2) muscle rigidity

3) metabolic acidosis

4) tachycardia

5) increased exhaled carbon dioxide

91
Q

Give 3 differentials for malignant hyperthermia

A

1) neuroleptic malignant syndrome: altered mental status, muscle rigidity, fever, and autonomic dysregulation.

2) serotonin syndrome: mental status changes, autonomic instability, and neuromuscular abnormalities.

3) sepsis: fever, tachycardia, and potential organ dysfunction.

92
Q

Definitive diagnosis of malignant hyperthermia?

A

Genetic testing, typically performed post-episode.

93
Q

Investigations in malignant hyperthermia?

A

1) genetic testing (definitive)

2) blood tests: metabolic acidosis, creatine kinase levels

3) ABG: resp & metabolic acidosis

4) core temp: hyperthermia

94
Q

How are CK levels affected in malignant hyperthermia?

A

Increased

95
Q

Management of malignant hyperthermia?

A

1) Immediate discontinuation of the triggering agent.

2) IV dantrolone

3) Restoration of normothermia

4) Correction of acidosis and electrolyte abnormalities.

5) Supportive e.g. oxygen, ventilation etc

96
Q

What drug is indicated in malignant hyperthermia?

A

IV dantrolene

97
Q

Mechanism of IV dantrolene in malignant hyperthermia?

A

It is a ryanodine receptor antagonist –> helps to decrease intracellular calcium concentration and reduce muscle metabolism.

98
Q

How can the restoration of normothermia be achieved in malignant hyperthermia?

A

Cooling techniques such as ice packs, cool intravenous fluids, and cooling blankets.

99
Q

In what situations should nitrous oxide be avoided in?

A

E.g. pneumothorax –> may diffuse into gas-filled body compartments and cause an increase in pressure

100
Q

Which general anaesthetic has proven anti emetic properties?

A

Propofol

101
Q

Which general anaesthetic may cause marked myocardial depression?

A

Sodium thiopentone

102
Q

Which general anaesthetic is a suitable agent for anaesthesia in those who are haemodynamically unstable?

A

Ketamine

103
Q

Which general anaesthetic may result in nightmares?

A

Ketamine

104
Q

Which general anaesthetic is post-op vomiting common in?

A

Etomidate

105
Q

Purpose of muscle relaxants in general anaesthetics?

A

They facilitate intubation and improve surgical access (particularly abdominal and laparoscopic procedures).

106
Q

Give 2 muscle relaxant agents

A

1) suxamethonium

2) rocuronium

107
Q

What does a simple general anaesthetic induction ‘recipe’ for tracheal intubation in a fit and well patient usually incorporate?

A

A quick acting opioid (e.g. fentanyl) and propofol.

108
Q

How is loss of consciousness confirmed in general anaesthesia?

A

Loss of vocal response/jaw thrust/eyelash reflex.

109
Q

Intravenous anesthetics work within one arm to brain cycle.

What does this mean?

A

If the drug is administered through an IV line in the arm, it is the time required to circulate back to the heart and then up to the brain (usually less than 1 minute).

110
Q

What is ‘one arm brain cycle’?

A

The time the drug takes to travel from the point of administration (e.g. cannula in hand) to the effect site (brain).

111
Q

How is tube placement within the trachea confirmed (i.e. what are the 3 essential checks)?

A

1) Symmetrical chest wall movement

2) Misting within the tube

3) More than 5 waveforms on capnography

These are confirmed whilst delivering 5 test breaths.

112
Q

How many test breaths are delivered whilst confirming tube placement within the trachea?

A

5

113
Q

Once tube placement is confirmed, what are the next 3 steps?

A

1) The tube length at the lip or teeth is noted

2) It is secured with a cloth tie or tape to prevent tube migration which may lead to endobronchial intubation or accidental extubation.

3) Patient is connected to ventilator

114
Q

What is the ‘maintenance’ goal during general anaesthetics?

A

To maintain a pain-free, unconscious state throughout surgery while ensuring physiological stability.

The choice of maintenance technique depends on the type and duration of surgery and clinician preference.

115
Q

How is a state of unconsciousness maintained during general anaesthetics?

A

1) Via IV access of inhalation (e.g. sevoflurane).

2) More recently, there has been a move towards total intravenous anaesthesia (TIVA) involving continuous, rapidly titratable IV infusions.

116
Q

What is TIVA usually a combination of?

A

Anaesthetic agent (e.g. propofol) plus a rapid-acting opioid such as remifentanil.

117
Q

What are 2 advantages of TIVA?

A

1) improved recovery profiles

2) reduced greenhouse gas emissions

118
Q

It is important to note that a patient can be unconscious but still experience pain during surgery.

What physiological parameters may indicate that an unconscious patient is experiencing pain?

A

tachycardia & HTN

119
Q

Anaesthetists aim to provide a ‘multimodal analgesia’ strategy for managing pain.

What does this mean?

A

Administering medications from multiple pharmacological classes to provide effective analgesia and reduce opioid requirements.

120
Q

What is a commonly used analgesiccombination for minor procedures in a healthy patient with no contraindications?

A

Paracetamol + NSAID + local anaesthetic (to surgical site) + breakthrough opioids if required.

121
Q

Give 2 other techniques for maintaining a pain-free intraoperative state?

A

1) Bolus or continuous infusion of opioids

2) Regional techniques (e.g. via peripheral nerve blockade or a central neuraxial block – spinal or epidural).

122
Q

What intraoperative monitoring is required?

A

1) Continuous monitoring of vital signs: blood pressure, heart rate, oxygen saturation, and end-tidal CO2 (capnography).

2) Depth of anaesthesia monitoring

3) Neuromuscular blockade assessment.

123
Q

How is the depth of anaesthesia typically measured?

Give 2 options

A

1) Using a bispectral index (BIS) monitor

2) Mean alveolar concentration (MAC)

124
Q

What does a BIS monitor analyse?

A

The brains electrical activity (EEG).

125
Q

When can MAC be used to measure the depth of anaesthesia?

A

If volatile agents are used to maintain anaesthesia.

126
Q

How can the degree of the neuromuscular blockade be assessed?

A

Using a peripheral nerve stimulator.

127
Q

Where are the leads typically over in a peripheral nerve stimulator?

A

Facial ofr ulnar nerve

128
Q

What is the most common physiological change you can expect with a standard general anaesthetic?

A

Hypotension.

This must be identified and treated promptly to ensure adequate organ perfusion.

129
Q

Cause of hypotension with standard general anaesthetics?

A

Due to the potent vasodilator effects of most inducation agents (except ketamine and etomidate).

130
Q

Which 2 general anaesthetics do NOT have potent vasodilator effects?

A

1) ketamine
2) etomidate

131
Q

What drugs can be to increase HR during surgery?

A

Antimuscarinics e.g. atropine, glycopyrronium.

If this fails –> adrenaline

132
Q

How do muscle relaxants work?

A

Block the neuromuscular junction from working:

Acetylcholine (the neurotransmitter) is released by the axon but is blocked from stimulating a response from the muscle.

133
Q

What are the 2 categories of muscle relaxants?

A

1) depolarising (e.g. suxamethonium)

2) non-depolarising (e.g. rocuronium and atracurium)

134
Q

What class of medication can reverse the effects of neuromuscular blocking medications?

A

Cholinesterase inhibitors (e.g., neostigmine)

135
Q

Give an example of a cholinesterase inhibitor

A

Neostigmine

136
Q

What medication is used specifically to reverse the effects of certain non-depolarising muscle relaxants (rocuronium and vecuronium)?

A

Sugammadex

137
Q

What are the 4 commonly used analgesic agents in anaesthetics?

A

1) fentanyl

2) alfentanil

3) remifentanil

4) morphine

138
Q

When are antiemetics often given in anaesthetics?

A

Antiemetics are often given at the end of the procedure by the anaesthetist to prevent post-operative nausea and vomiting.

139
Q

What are 3 common antiemetics given for prophylaxis given at the end of the operation?

A

1) Ondansetron

2) Dexamethasone

3) Cyclizine

140
Q

Mechanism of ondansetron?

A

5HT3 receptor antagonist

141
Q

Who is ondansetron avoided in?

A

Patients at risk of prolonged QT interval.

142
Q

Who should dexamethasone as a post-op antiemetic be used with caution in?

A

Diabetic or immunocompromised patients.

143
Q

Mechanism of cyclizine?

A

Histamine (H1) receptor antagonist

144
Q

Who cyclizine be used with caution in?

A

Heart failure & elderly patients

145
Q

What needs to have worn off before waking the patient during general anaesthetics?

A

Muscle relaxant

146
Q

What can be used to determine whether the muscle relaxants have worn off?

A

A nerve stimulator: used to test the muscle responses to stimulation to ensure the muscle relaxant effects have ended.

147
Q

Which nerves are commonly tested to see if muscle relaxants have worn off?

A

1) Ulnar nerve at the wrist: watch for thumb movement (twitches).

2) Facial nerve at the temple: watch for movement in the orbiculares oculi muscle at the eye.

148
Q

What is involved in testing the facial nerve with nerve stimulators?

A

This involves a train-of-four (TOF) stimulation.

This is where the nerve is stimulated 4 times to see if the muscle responses remain strong (indicating it has worn off) or whether they get weaker with additional stimulation (indicating it has not fully worn off).

149
Q

What result of train-of-four (TOF) stimulation indicates that muscle relaxants haven’t fully worn off?

A

Muscle responses get weaker with additional stimulation.

150
Q
A
151
Q

Steps in ‘emergence’ during general anaesthetics?

A

1) Ensure muscle relaxant has worn off

2) Stop inhaled anaesthetic

3) Extubate when they are breathing for themselves

152
Q

What are the 2 common side effets of general anaesthetics?

A

1) sore throat

2) post-op N&V

153
Q

What are some significant side effects of general anaesthesia?

A

1) Accidental awareness (waking during the anaesthetic)

2) Aspiration

3) Dental injury, mainly when the laryngoscope is used for intubation

4) Anaphylaxis

5) Cardiovascular events (e.g., myocardial infarction, stroke and arrhythmias)

6) Malignant hyperthermia (rare)

7) Death

154
Q

What is the main contraindication for thiopentone?

A

Porphyria

155
Q

How does ketamine affect BP & HR?

A

Increased HR & BP

156
Q

How long do induction agents typically last?

A

4-10 minutes

157
Q

What is the most commonly used IV maintenance anaesthesia?

A

Propofol infusion

158
Q

What are 3 commonly used inhalational agents?

A

1) Sevoflurane (MAC 2%)
2) Desflurane (MAC 6%)
3) Isoflurane (MAC 1.15%)

159
Q

What is MAC?

A

It is defined as the minimum alveolar concentration of inhaled anaesthetic at which 50% of people do not move in response to a noxious stimulus.

160
Q

Which inhalational agent is sweet smelling?

A

Sevoflurane

161
Q

Which inhalational agent has the max greenhouse effect?

A

Desflurane

162
Q

Which inhalational agent has the least effect on organ blood flow?

A

Isoflurane –> used in organ donation

163
Q

Adverse effects of suxamethonium?

A
  • muscle pains
  • fasciculations
  • Hyperkalaemia
  • malignant hyperthermia
  • rise in ICP, IOP and gastric pressure
164
Q

Give an example of a depolarising muscle relaxant

A

Suxamethonium

165
Q

Give examples of non-depolarising muscle relaxants

A

Short-acting: Mivacurium

Intermediate acting: Vecuronium, rocuronium, Atracurium.

Long acting: Pancuronium

166
Q

Benefits of non-depolarising muscle relaxants?

A

Slow onset and variable duration, less side effects.

167
Q

What is used to reverse non-depolarising muscle relaxants?

A

Neostigmine & Glycopyrrolate

168
Q

What is the most common short acting opioid used at time of anaesthesia induction?

A

Fentanyl

169
Q

What is the most commonly used oral opioid in adults?

A

Codeine

170
Q

Which 2 NSAIDs are given IV?

A

1) Ketorolac
2) Parecoxib

171
Q

Which opioid can be used with morphine?

A

tramadol

172
Q

What medications should be prescribed for post-op?

A

1) Rescue analgesia
2) Rescue antiemetics
3) Fluids
4) Other medications as indicated

173
Q
A

Yr 4 - ACC (73 decks)

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