Anaesthetics and Analgesia Flashcards

1
Q

What is anaesthesia?

A
  • any lipid-soluble agent the causes depression of the brain in a predictable order
    • Cortex
    • Midbrain
    • Spinal cord
    • Medulla
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do anaesthetics work?

A
  • Increase tonic inhibition
    • increased action of GABA receptors
    • Glycine
  • Inhibit excitatory synaptic transmission
    • inhibiting ligand-gated ion-channels
    • NMDA receptors
    • opening K+ channels
    • Nicotinic
    • Serotonin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is anaesthesia administered?

A
  • Inhale
    • Oxygen
    • NO
    • Isoflurane
  • Injected
    • Propofol
    • Thiopental
    • Etomidate
    • Ketamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Oxygen as an anaesthetic agent

  • action
  • side- effects
A
  • generally good for you

Side- effects

  • O2 free radicals
  • CNS convulsions
  • Pulmonary oxygen toxicity
  • Retrolental fibroplasia
  • CO2 narcosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Nitrous oxide as an anaesthetic agent

  • action
  • side-effects/ contraindications
A
  • good analgesia but usually combined with other inhaled drugs for a good anaesthetic effect
  • Fast induction/ recovery

Side-effects

  • Cardio-respiratory depressant: diffusional hypoxia during recovery
  • risk of bone marrow depression with prolonged use
    • avoided in anaemic and 12 deficient patients
  • can causes expansion in gaseous cavities
    • contraindicated in pneumothorax, vascular air embolus or in an obstructed intestines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What chemical properties of inhalation need to be considered?

A
  • Non-irritant
  • Low blood-gas solubility
  • High potency (Minimum alveolar conc. | MAC)
  • Minimal side effects
  • bio-transmission
  • non-toxic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Desflurane as a general anaesthetic agent

A
  • Fast induction/ recovery
    • used for day-case surgery
  • moderately expensive and environmentally damaging
  • Sevoflurane is similar (expensive)

Side-effects

  • respiratory tract irritation
  • cough
  • bronchospasm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Isoflurane as a general anaesthetic agent

A
  • a relatively cheap stable non-flammable halogenated ether
  • widely used and replaced halothane
  • medium induction/recovery rate

Side-effects

  • irritable to the airway
  • possible risk of coronary Ischaemia in susceptible patients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give an overview of Intravenous agents

A
  • they are usually induction agents/ iv opiate
  • rapid onset and pleasant sensations
  • Lipid soluble
  • short-acting, metabolised
  • cause CVS/RS depression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Thiopentone as an anaesthetic agent

A
  • Powder
  • Smell of garlic
  • Antiepileptic
  • CVS/RS depression
  • Anaphylaxis/ arterial
  • Half-life 10 hours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Propofol as an anaesthetic agent

A
  • Short-acting agent used for induction
  • maintenance of GA and sedation
  • onset within minutes of injection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

2,6-diisopropylphenol as an anaesthetic agent

A
  • Solvent
  • Redistribution half-life - 4 minutes
  • Elimination half-life - 4 hours
  • Minimal accumulation - TIVA
  • Antiemetic
  • Antiepileptic
  • Painful to inject
  • Abnormal movements
  • CVS/RS effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give an overview the use of muscle relaxants

A
  • Dangerous drugs
  • Muscle paralysis
  • Facilitate intubation
  • Maintain paralysis for surgery/ventilation
  • Depolarising
  • Non depolarising
  • Anaesthetists only
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give an overview of depolarising agents

A
  • Suxamethonium
  • Post-synaptic membrane
  • Mimics acetylcholine
  • Rapid onset offset
  • Short half life ~ 2min
  • Plasma cholinesterase
  • Multiple side effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give an overview of non-depolarising blockers

A
  • Competitive with Ach
  • Ach moiety blocks Na channel with size
  • Duration is variable
  • Slower onset and slower offset
  • Steroid group: rocuronium
  • Benzylisoquinoliniums: atracurium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give an overview of the use of N-m blocking agents

A
  • Intubation
  • Surgery
  • Ventilation
  • Transfer
  • Side effects
  • Reversal
17
Q

Gate theory - Pain

A
  • C fibres lets pain through
  • Ab fibres stimulate inhibitory neurons
  • Descending pathways prevent the central passage
18
Q

Give an overview of Opioids

A
  • Act on opioid Receptor and antagonised by Naloxone
  • Naturally occurring eg Morphine ,Codeine
  • Semi-Synthetic eg Diamorphine
  • Synthetic eg Fentanyl
  • Weaker eg Codeine
19
Q

What methods of administration are there for administration?

A
  • Intravenous pca/infusion
  • Intramuscualr
  • Oral
  • Intra nasal/aersol
  • EPidural/spinal
20
Q

Where are Opioid receptors found?

A
  • POns and the Midbrain
  • Periaqueductal Grey Matter
  • Nucleus Raphe Magnus
  • Spinal COrd Posterior Horn 1 and 2
  • G.I.T
  • Peripheral tissues

Subtypes

  • Mu 1 and 2: OP3
  • Delta: OP1
  • Kappa: OP2
21
Q

Give an overview of the use and effects of morphine

A

Effects: significantly reduces pain

Side effects

  • Resp. depression/ airway loss
  • N&V
  • Constipation/Pruritis
  • Miosis
22
Q

What is Naloxone?

A
  • drug used to treat opioid overdose
  • needs to be regularly monitored and regulated
23
Q

Give an overview of Ketamine and it’s effects

A
  • acts on NMDA Receptors
    • Kappa and delta receptors
    • Not GABA
  • Analgesic local/general
  • Anaesthetic
  • Sedative
  • SIDE EFFECTS: emergence phenomena
24
Q

Give an overview of NSAIDS and their effects

A
  • Act by inhibiting Cyclooxygenase 1 and 2
  • Analgesic, Antipyretic, Anti-inflammatory
  • Side Effects
    • Gastric Irritation
    • Bronchospasm
    • Renal Impairment
    • Platelet function ASPIRIN
25
Q

What is the effect of Aspirin in the body?

A
  • Acetylsalycilic acid
  • causes Oxidative phosphorylation
  • causes Air Hunger
  • Reyes Syndrome
26
Q

Give an overview of the effect Paracetamol has on the body?

A
  • Mechanism of Action: Central prostaglandin effect/unknown
    • Side effectsOVERDOSE Hepatotoxicity/glutathione depletion
  • N acetylcysteine
27
Q

Give examples of other Analgesia?

A
  • Anxiolysis
  • Local anaesthetics
  • Antidepressants,antiepileptics
  • Guanethidine, ketamine, clonidine
  • Acupuncture
  • Inhalational Nitrous oxide/penthrane
  • Tramadol
28
Q

What are anti-emetics give examples?

A
  • drug used to treat nausea and vomiting
  • Cyclizine
  • Ondansetron
  • hyoscine
  • Metoclopramide
  • Steroids
  • Prochlorperazine
  • cannabinoids
29
Q

The tiers of the Ramsay Sedation scale

A
  • Patient Anxious
  • Cooperative
  • Responds only to commands
  • Brisk response to Glabellar Tap/Shout
  • Sluggish Response
  • No response
30
Q

Give an overview of Benzodiazepines

A
  • Midazolam, Diazepam, Lorazepam
  • Routes of administration
    • suppositories, IV injection(triazolam, flunitrazepam, and diazepam emulsion)
  • PHYSIOLOGY
    • Gabba- aminobutyric Acid
    • Inhibitory Neurotransmitter
    • Receptors A and B
31
Q

What are the side effects of Benzodiazepines

A

used for

  • loss of airways
  • respiratory depression
  • ABC
  • Flumazenil can reverse the effects of benzodiazepines
32
Q

Give examples of other sedatives

A
  • Low dose vapours
  • Ketamine
  • Hyoscine
  • Propofol Low dose
  • Major Tranquilisers
33
Q

What are the classifications of local anaesthetics?

A
  • Amides
    • Lignocaine, Prilocaine, Bupivacaine
  • Esters
    • Cocaine, Amethocaine
34
Q

Explain the mechanism of action of local anaesthetics

A
  • Na channel blockade
  • Un-ionized drug through the membrane into the axoplasm
  • Protonated
  • Blocks channel–> blocking the action potential
35
Q

How are local anaesthetics administered?

A
  • Anatomy Local Blocks /Ultrasound
  • Spinal Epidural Caudal
  • Skin
  • Aerosol/Nebulised
  • Combination with GA Part of Triad
36
Q

How do side effects of local anaesthetics present?

A
  • restlessness, disorientation, tremors, drowsiness
  • lightheadedness circumoral numbness, dizziness visual changes
  • respiratory depression
37
Q

What effect does the toxicity of local anaesthetics cause in the

  • cardiovascular and
  • central nervous system
A

Cardiovascular

  • dysrhythmias, Cardiac depression

CNS

  • fitting/ anxiety/ loss of consciousness
  • circumoral numbness
38
Q

How is local anaesthetic toxicity treated?

A
  • ABC
  • Oxygen
  • Lipid 20%
  • Dysrhythmias/fitting