Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 2 > ANAESTHESIOLOGY > Flashcards

ANAESTHESIOLOGY Flashcards

1
Q

What is anaesthesia?

A

Controlled temporary loss of sensation which is induced for medical purposes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the types of anaesthetics?

A

Local anaesthetics
Inhalational anaesthetics
General anaesthetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens to the cell when there is noxious stimuli?

A

Transient cation receptor channels open and allow the influx of positive ions to the cell for cell depolarisation of first order neurons to the spinal cord. On the membrane surface of the cell, voltage gated Na+ channels are present which have an intracellular gate to control flow. When depolarisation occurs, this allows influx of Na+ but the intracellular gate shuts to prevent further influx, and only opens again when there is cell depolarisation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the types of local anaesthetic administrations?

A

Topically on the skin
OR
Infiltration through the skin, such as injection directly to muscle or near the spinal cord.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do local anaesthetics work?

A

They bind to voltage gated Na+ channels on the cytoplasmic surface and prolong its inactivation for analgesia.
They tend to target small and myelinated neurons.

In large doses, they can cause loss of temperature, touch and motor function. Because they are quickly absorbed by the bloodstream, to prolong mechanism of action it is typically administered with norepinephrine.

They have a reduced effectivity in acidic tissues that are hypoxic or infected because they become ionised.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the types of local anaesthetics?

A

Ester anaesthetics
Amide anaesthetics

These must be administered with epinephrine, a vasoconstrictor to ensure the aanaesthetic does not enter systemic circulation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the ester anaesthetics?

A

Includes cocaine and Privocaine. Ester anaesthetics are hydrolysed in the bloodstream to plasma esterases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the physiological effects of cocaine?

A

Cocaine reduces the breakdown of catecholeamines, causing the body to go into a sympathetic state with vasoconstriction, tachycardia and arrythmia.
Cocaine reduces the breakdown of dopamine which can result in addiction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the amide anaesthetics?

A

Lidocaine, bupivicaine and levobupivicaine- these are hydrolysed in the liver by cytochrome P450 enzymes.
->Lidocaine has a short duration of action and is the most frequently used amide anaesthetics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the side effects of local anaesthetics?

A

They can reduce breakdown of inhibitory neurons like GABA and glycine and in high doses, can lead to CNS depression and respiratory arrest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which amide anaesthetics has a high cardio toxicity?

A

Bupivicaine- when injected into blood vessels, it results in myocardial depression. It has the longest duration time of all the amide anaesthetics and is used in C section.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the stages of anaesthetics?

A

1) Induction: administering the anaesthetic from analgesia to loss of consciousness of patient.

2) Excitement phase: downregulation of inhibitory neurons causes increased muscle tone and reflexes. There is vomiting, greater heart and respiratory rate and pupil dilation, respiratory compromise can occur here.

3) Surgical/Maintenance phase: Skeletal muscle relaxes, vomiting cessation and eye movements stop.

Reversal phase
or
4)Medullary phase: Overdose of anaesthetic results in medullary and brain stem depression, causing respiration cessation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do general anaesthetics work?

A

General anaesthetics are used to produce unconsciousness, loss of reflexes and analgesia. It can be divided into inhalational and intravenous anaesthetics.

They act on inhibitory GABA receptors present in the CNS to prolong the influx of Cl- for hyperpolarisation to suppress neuron excitability and induce a state of loss of consciousness.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the targets of general anaesthetics?

A

They enter the bloodstream and act on the thalamus and reticular activating system for unconsciousness. They act on the prefrontal cortex, hippocampus and amygdala for amnesia. It acts on the spinal cord for loss of motor activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the side effects of general anaesthetics?

A

Causes decreased cardiac contractility, sympathetic inhibition and respiratory depression. At high concentrations, all brain functions are depressed which can lead to death.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the intravenous general anaesthetics?

A

Etomidate, propafol and thiopentene sodium
-> These are delivered into the bloodstream and target the brain within 30 seconds for GABA agonist to induce hyperpolarisation via Cl- influx. They are then metabolised by the liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the properties of intravenous anaesthetics?

A

Rapid onset, which are metabolised in the liver. It can cardiac suppression and respiratory suppression and can cause anaphylaxis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the properties of thiopentene sodium?

A

Short acting intravenous general anaesthetic which has an analgesic effect and is used in the induction phase. It causes apnoea following administration, and respiratory depression, cardiovascular suppression so drop in blood pressure.

When given intrarterially, causes severe limb pain and becomes life threatening.CANNOT be given for those with porphyria.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the properties of propofol?

A

Propofol is an intravenous anaesthetic given for induction and maintenance which causes pain on injection due to irritation of skin and mucosa, so it is generally administered with lidocaine.

It has hypnotic effects and causes myocardial depression and hypotension, as well as hypersensitivity. It causes rhabdomyolysis and vomiting.

CANNOT BE GIVEN to children under 3.

20
Q

What are the properties of etomidate?

A

Etomidate is an intravenous general anaesthetic provided at a very low dose, which has hypnotic effects due to GABA stimulation. It is beneficial for those with cardiac conditions because it has little effect on the heart. There is a minimal risk for respiratory depression.

It causes adrenal suppression of cortisol and myoclonus.

21
Q

What is myoclonus?

A

Brief and involuntary muscle twitching which affects specific areas of the body.

22
Q

What are the group 2 general anesthetics ?

A

Ketamine, Nitric oxide and MDMA.

23
Q

What is the mechanism of action of group 2 anaesthetics?

A

They block glutamate from binding to the NMDA receptor for Ca2+ influx for pain transmission. They also act on a 2 pore K+ channel for K+ efflux to reduce neuronal excitability.

24
Q

What are the properties of ketamine?

A

Ketamine is a phencyclidizine derivative which has an analgesic effect and causes increased respiratory rate, cardiac output and preserves laryngeal reflexes for salivary secretions. It targets the NMDA receptors and can lead to disassociations and hallucinations.

25
Q

Which intravenous anaesthetic can be used in the maintenance phase?

A

Propofol.

26
Q

What is the critical receptor theory?

A

Anaesthetics disrupt the ionic channels.

27
Q

What is the pertubation theory of anaesthetics?

A

Disrupts the annular lipids associated with the ionic channels.

28
Q

What are the anaesthetic gases?

A

Anaesthetics delivered via inhalation which includes both
Vapour anaesthetic: liquified at room temperature
Gas anaesthetics: gas at room temperature

They are used for induction and maintenance of anaesthesia by stimulating GABA receptors and inhibition NMDA receptors against glutamate. They are mainly metabolised in the lungs

29
Q

What is MAC?

A

Minimum alveolar concentration which prevents 50% of patients moving in response to a painful stimulus.

30
Q

What are the examples of inhalational anaesthetics?

A

Sevoflurane and Isoflurane which are metabolised by the liver but can lead to renal impairment due to formation of Fluoride ions. They can trigger malignant hyperthermia.

31
Q

What are the properties of nitric oxide?

A

It is a gas anaesthetic which is teratogenic due to bone marrow suppression causing megaloblastic anaemia and the post-operative nausea and vomiting. (PONV)

32
Q

What are the volatile anaesthetics?

A

Liquid anaesthetics at room temperature and require the use of vaporiser for general administration. Causes reduction in cardiac output, vascular resistance, blood pressure and respiratory depression.

33
Q

What are the properties of volatile anaesthetics?

A

It has a slow onset and rely on alveolar gas exchange, due to being inhaled. It causes cardiac suppression and respiratory suppression.

34
Q

What are the neuromuscular blocking agents?

A

Block transmission of neurotransmitters and cause paralysis of skeletal muscles. There are two classes of neuromuscular blocking agents:
Depolarising blocking agents
Non-depolarising blocking agents

35
Q

Why are neuromuscular blocking agents used?

A

They induce muscle relaxation for surgery and useful for tracheal inhalation and mechanical ventilation.

36
Q

How does depolarising blocking agents work?

A

They act on the post-synaptic receptor and occupy the binding site as an agonist, prolonging the depolarisation and resulting in loss of sensation. It has a short duration of action.

37
Q

How do non-depolarising blocking agents work?

A

They act as competitive antagonists to acetylcholine on the pre-synaptic receptor and post-synaptic receptor which causes the loss of sensation.

38
Q

What are the properties of succinylcholine?

A

It is a depolarising muscular blocking agent which is structurally similar to AcH. It causes bradycardia, muscle pain and muscle hyperthermia. It can cause raise in K+ and increased pressure in the cranium, eyes and stomach. It is typically used for muscle relaxation for surgery.

39
Q

What is malignant hyperthermia?

A

Hyper metabolic response by the body to inhalation anaesthetics such as isoflurane and sevoflurane and the depolarising blocking agent succinylcholine. It causes muscle rigidity, tachycardia and rapid breathing and is associated with metabolic acidosis.

40
Q

What is atracurium?

A

Non depolarising neuromuscular blocking agent which must be avoided in asthmatic patients. It has little effects on the kidney or liver.

41
Q

What is anaesthetic depth?

A

The degree to which the anaesthesia administered depresses the CNS to prevent memory and recall of the surgery and pain sensation. This is dependent on the dose of anaesthetic, the machines used to deliver it and patient-specific resistance. It is tested through various stimuli.

42
Q

How can the depth of anaesthesia be measured?

A

Minimum alveolar concentration (MAC)
Constant plasma concentration (Cp50)
Guedel’s scale
Lower oesophageal contraction

43
Q

What is Guedel’s scale?

A

Used to measure the anaesthetic depth when using only an inhalational anaesthetic. It assesses the ocular movements, muscle reflexes, respiratory rate, heart rate and blood pressure.

44
Q

What is the PRST scoring system?

A

It is used to measure anaesthetic depth of based on:
Pressure of blood
Rate of heart
Sweating
Tears

45
Q

What are the objective methods of measuring anaesthetic depth?

A

Spontaneous Electromyography
Lower oesophageal contractility
BIS- bispectral index

Year 2 (247 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions