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4th Year ACC > Anaesthetics > Flashcards

Anaesthetics Flashcards

1
Q

Three things needed in anaesthetic?

A

Amnesia

Akinesis

Analgesia

+not harmful to patient

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2
Q

What is meant by amnesia for an anaesthetic?

A

No recall/response to noxious stimuli

Unconscious

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3
Q

What are the three steps of an anaesthetic?

A

Induction

Maintenance, monitoring

Reversal

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4
Q

What is induction and how long does it take and last?

A

Inducing LOC

Takes 10-20 secs and lasts 4-10mins

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5
Q

What are the 4 induction agents?

A
  1. Propofol
  2. Thiopentone
  3. Ketamine
  4. Etomidate
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6
Q

What is the most commonly used induction agent?

A

Propofol 95%

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7
Q

Propofol dose

A

1.5-2.5mg/kg

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8
Q

Two benefits of propofol

A

Suppresses airway reflex so broncho/laryngospasm unlikely

Low PONV

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9
Q

4 disadvantages of propofol

A

Lowers HR and BP

Painful to inject as thicc

Involuntary movements

Hiccups

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10
Q

Thiopentone dose

A

4-5mg/kg

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11
Q

Thiopentone class

A

Barbiturate

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12
Q

Thiopentone is mainly used when?

A

RSI (fast acting)

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13
Q

Benefit of thiopentone

A

Anti-epileptic, protects brain

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14
Q

5 disadvantages thiopentone

A

Lowers BP increases HR

Rash

Bronchospasm

If intra-arterial –> thrombosis and gangrene

Contraindicated in porphyria

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15
Q

Ketamine dose

A

1-1.5mg/kg

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16
Q

What does ketamine cause

A

Dissociative anaesthesia

Anterograde amnesia and profound analgesia

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17
Q

What is ketamine best used for

A

Sole anaesthetic in short, painful procedure

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18
Q

Ketamine benefit?

A

Bronchodilation

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19
Q

4 ketamine disadvantages

A

Slow onset

Increases HR and BP

N&V

Emergence phenomenon/delirium (esp in young women)

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20
Q

Etomidate dose

A

0.3mg/kg

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21
Q

Etomidate class

A

steroidal

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22
Q

Etomidate three benefits

A

Rapid onset

Haemodynamic stability (good in e.g. HF)

Least likely to = hypersens reaction

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23
Q

4 disadvantages etomidate

A

Pain to inject

Spont movement

Adrenal-cortico suppression (needed to maintain BP)

High incidence PONV

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24
Q

What are two ways you can maintain anaesthesia?

A

Propofol infusion (total IV anaesthesia)

Inhalation agents (aka volatiles, vapours)

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25
Q

What are the four inhalation agents?

A

Isoflurane 1.15%

Sevoflurane 2%

Desflurane 6%

Enflurane 1.6%

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26
Q

Benefit of isoflurane

A

Least effect on organ blood flow

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27
Q

Benefit of sevo

A

sweet smell

gas induction e.g. children

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28
Q

Benefit of desflurane

A

low lipid solubility

rapid onset and offset

long ops

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29
Q

Drawback of desflurane

A

Airway irritant- only use if intubated

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30
Q

What controls the concentration of volatile agent?

A

The proportion of O2/NO2 to the volatile. The machine is a closed circuit and the agent is not metabolised so remains in the circuit. In and En Sevo will eventually reach equilibrium. To stop the anaesthetic, increase the o2 to reduce the proportion of the volatile.

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31
Q

How do you get an idea of the brain concentration of the volatile agent?

A

End tidal measurement e.g. EnSevo

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32
Q

What is the benefit of using NO2?

A

Allows you to give less of the volatile for the same effect- good in elderly. It increases the MAC. Good to get the patient deeper in a very stimulating procedure e.g. abscess. NB NO2 must have some O2 as well

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33
Q

What is an SE of NO2?

A

PONV

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34
Q

What is MAC?

A

Minimum alveolar concentration

The conc of the vapour that prevents the reaction to a standard surgical stimulus in 50% subjects

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35
Q

Is analgesia given before or after the induction agent?

A

Before so it has time to work

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36
Q

When is analgesia required in an operation?

A

All the time including airway insertion and post-op

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37
Q

What analgesia is given intra-op?

A

Short acting opioid

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38
Q

three short acting opioids that are given intra op?

A

Remifentanyl

Alfentanyl

Fentanyl

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39
Q

Which opioid is most often given intra-op?

A

Fentanyl (90%)

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40
Q

Which opioid is more short acting?

A

Alfentanyl

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41
Q

How is remifentanyl given?

A

IVI

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42
Q

How do LAs work?

A

Inhibit sodium channel in nerve axon

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43
Q

When should you not use LA with adrenaline?

A

Penile block or digits

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44
Q

What 2 types of chemical are LAs?

A

Esters or amides

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45
Q

Name two topical analgesics

A

EMLA (50/50 lignocaine and prilocaine)

Ametop (tetracaine 4% gel)

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46
Q

Max dose lignocaine, with and without adrenaline

A

3mg/kg

7mg/kg with adrenaline

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47
Q

Max dose bupivacane , with and without adrenaline

A

2 and 2mg/kg

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48
Q

Max dose prilocaine, with and without adrenaline

A

6mg/kg and 9mg/kg

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49
Q

A 1% solution has how many mg/ml

A

10

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50
Q

Symptoms LA toxicity

A

Perioral numbness and tingling

tinnitus

Seizure

Arrhythmia

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51
Q

How do you treat LA toxicity?

A

Anaesthetic emergency!

ABCDE

100% O2

Stop surgeon, send for help

Crash trolley

Intralipid to soak up

Start IV fluids

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52
Q

Other than giving too much, how can LA toxicity occur?

A

Injecting into a vessel

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53
Q

What analgesic do you give intra and post-op?

A

Long acting opioids e.g. morphine, oxycodone, pethidine

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54
Q

How many days to become dependent on long acting opioid?

A

17

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55
Q

Under what weight (of a patient) do you reduce the dose of paracetamol?

A

45kg

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56
Q

Can you give tramadol with morphine?

A

yes

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57
Q

Can you give dihydrocodeine with morphine?

A

No

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58
Q

What is the dose of ketamine for analgesia?

A

0.25-0.5mg/kg

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59
Q

What is the anaesthetic way of assessing pain?

A

RAT

Recognise

Assess

Treat

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60
Q

What is allodynia?

A

Normal stimulus is painful

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61
Q

What is nociceptive pain?

A

Due to tissue injury, is protective

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62
Q

What is neuropathic pain?

A

Not protective

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63
Q

What is chronic pain? time scale

A

> 3m

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64
Q

When might you get hypo/hyperalgesia?

A

Peripheral neuropathy

Fibromyalgia

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65
Q

describe the pain pathway

A

nociceptors, peripheral nerves –> dorsal horn of the SC –>decassation –> secondary nerve up SC in spinothalamic tract –> thalamus –> cortex, limbic system, brainstem –> modulation in corticospinal tract (e.g. withdraw hand from burning stimulus)

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66
Q

Does the WHO analgesic ladder apply in severe acute nociceptive pain?

A

Reverse it

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67
Q

In the ‘assess’ part of RAT what 4 features of the pain do you need to determine?

A

Cancer/non-cancer

Noci or neuro

Acute/chronic

Other factors

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68
Q

Patient controlled analgesia is usually what drug?

A

IV morphine

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69
Q

What four structures does an epidural needle pass through to get to the epidural space?

A

Skin

SC fat

Supraspinous ligament

Ligamentum flavum

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70
Q

What space does a spinal block go into?

A

Sub arachnoid space

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71
Q

What does subarachnoid space contain?

A

CSF

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72
Q

What structures does a spinal block needle pass through?

A

Skin

SC fat

Supraspinous ligament

Ligamentum flavum

Epidural fat

Dura

Arachnoid

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73
Q

How long does an epidural take to work?

A

15-30m

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74
Q

What is in the epidural space?

A

Fat and blood vessels

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75
Q

What level do you put in an epidural?

A

Depends on op

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76
Q

Risk damage to SC above what level epidural?

A

L1

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77
Q

An epidural is put into what level during labour?

A

L2-S2

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78
Q

At what level does the subarachnoid space end?

A

S1

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79
Q

At what level does the spinal cord end?

A

L1/L2

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80
Q

At what level does the epidural spac end?

A

Sacrococcygeal hiatus

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81
Q

What level does a spinal go into?

A

L3-L5 (in SA space but below SC)

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82
Q

What is in a spinal block?

A

Usually LA and opioid

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83
Q

How long does a spinal take to work?

A

5-10min

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84
Q

Does a spinal also block motor?

A

Yes

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85
Q

How do you test a spinal has worked?

A

Cold spray as spinothalamic tract= pain and temp

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86
Q

What score is used to test motor block in a spinal anaesthetic?

A

Bromage scale

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87
Q

What is a side effect of spinal block?

A

Decreased BP (decreased sympathetic NS)

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88
Q

Spinal vs epidural:

Which is a single injection, which has a cannula for continuous infusion?

A

Spinal is single injection

Epidural continuous.

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89
Q

How is a nerve/plexus block given?

A

US guided

LA around the nerve (not into a vessel!)

Use cold spray to check

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90
Q

How long does a regional block last?

A

12-24hr

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91
Q

Is akinesis given in all surgeries?

A

No

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92
Q

What are the two types of muscle relaxant?

A

Depolarising and non-depolarising

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93
Q

How do depolarising muscle relaxants work?

A

Similar action to acetyl-choline on the nicotinic receptors at the synapse. But are hydrolysed very slowly by AChE

So muscle contraction occurs –> fatigue –> relaxation

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94
Q

Example of depolarising muscle relaxant?

A

Succinylcholine AKA suxamethonium

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95
Q

Suxamethonium dose

A

1.5-5mg/kg

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96
Q

Sux use?

A

RSI

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97
Q

SEs depolarising muscle relaxants

A

Fasciculation

Hyperkalaemia

Malignant hyperthermia

Raised ICP, raised IOP, raised gastric pressure

Sux apnoea

Muscle aches

Initially tachycardia, then bradycardia with repeated doses (can give atropine)

Increased salivation

Awareness (muscle relaxants in general)

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98
Q

How do non-depolarising muscle relaxants work?

A

Block nicotinic receptors so there is no contraction (competitive with ACh)

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99
Q

Example non-depolarising muscle relaxant

A

Atracurium

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100
Q

What is the onset of non-depolarising muscle relaxant?

A

Slow

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101
Q

Suxamethonium is made up of ?

A

2 Ach molecules together

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102
Q

How do you reverse non-depolarising muscle relaxant?

A

Neostigmine and glycopyrrolate

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103
Q

What is neostigmine?

A

Anti-cholinesterase- prevents the breakdown of ACh

Induces muscarinic effects of ACh e.g. bradycardia, excessive salivation, so you use Glycopyrrolate too.

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104
Q

How does glycopyrrolate work? SE?

A

Antimuscarinic

SE= N&V

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105
Q

What is a quicker but more expensive way to reverse non-depolarising muscle relaxant?

A

Suggamadex

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106
Q

Can non-depolarising muscle relaxants trigger malig hyperthermia?

A

No

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107
Q

Do depolarising muscle relaxants need to be reversed?

A

No, their duration is short and reverse is spontaneous

108
Q

How do you check a muscle relaxant is working in theatre?

A

Use a nerve stimulant and ‘train of 4’ technique

109
Q

BP= ? x ? x?

A

HR x SV x SVR

110
Q

HR x SV =?

A

CO

111
Q

What are vasopressors used for?

A

Treat hypotension

112
Q

What is the effect of alpha receptor agonism?

A

Vasoconstriction

113
Q

What is the effect of beta receptor agonism?

A

increase HR

114
Q

What is the mechanism (and so the physiological effect) or ephedrine?

A

alpha and beta agonist

Increases BP and HR

115
Q

What is the mechanism (and so the physiological effect) or phenylephrine?

A

100% alpha agonist so increases BP but decreases HR (compensatory response to increased BP)

116
Q

What is the mechanism (and so the physiological effect) or metaraminol?

A

99% alpha, 1% beta agonist so increases BP but decreases HR (compensatory response to increased BP)

117
Q

Reflex bradycardia is more pronounced in which vasopressor?

A

Phenylephrine

118
Q

In general anaesthetic drugs have what effect on blood vessels?

A

Vasodilation so decrease SVR

119
Q

What is the mechanism of noradrenaline?

A

alpha and beta

120
Q

Mechanism adrenaline?

A

alpha and beta

121
Q

What is the effect of noradrenaline at a low and high dose?

A

Low- increases SVR

High- increases HR as well

122
Q

As well as noradrenaline and adrenaline, what other vasopressors are used in ICU/severe sepsis?

A

Dobutamine and glycopyrrolate

123
Q

What inotrope is used in ICU etc?

A

Atropine

124
Q

What is the action of atropine?

A

Anticholinergic- blocks parasympathetic NS so HR increased

125
Q

What are the neurotransmitters in the sympathetic and parasymp NSs?

A

Symp- pre-ganglionic is Ach, post-ganglionic is mainly noradrenaline (adrenergic)

Parasymp- All ACh (cholinergic)

126
Q

What is the incidence of PONV in general anaesthesia

A

20-30%

127
Q

Ondansetron action?

A

5HT3 blocker

128
Q

Cyclizine action?

A

Antihistamine

129
Q

Which steroid can be used as an antiemitic? It is most effective when given when?

A

dex

when given before anything else

130
Q

Metoclopramide action

A

Antidopaminergic

131
Q

What is a SE of cyclizine?

A

Tachycardia

132
Q

What is done in post operative care?

A
  1. suction, take out intubation
  2. reverse drugs
  3. O2 during transfer
  4. Handover- brief Hx of op, anticipated problems, intra op analgesia and PONV prophylaxis
  5. Prescribe rescue analgesics, antiemitics, fluids etc.
133
Q

What are the steps in induction when an LMA is used?

A
  1. pre oxygenate
  2. analgesic
  3. induction agent
  4. turn on volatile
  5. bag valve ventilation
  6. LMA insertion
134
Q

What are the steps in induction when intubation is used?

A
  1. pre oxygenate
  2. analgesic
  3. induction agent
  4. muscle relaxant
  5. turn on volatile
  6. bag valve ventilation
  7. intubate
135
Q

Why do you often intubate in abdominal surgery?

A

Gas pumped into abdo squashes gastric contents- more risk of aspiration so this protects the airway.

136
Q

At which two points can you extubate? Why?

A

Deeply anaesthetised or fully awake- otherwise laryngospasm

137
Q

What is included in a pre op assessment?

A

History-

  1. Cardiac: exercise tolerance, chest pain, HTN, PND, orthopnoea
  2. Resp: Asthma, chest infection, cough, smoking
  3. Airway: teeth/dentures, mouth opening, neck movements
  4. Previous anaesthesia: any problems, family history (ask specifically about Sux ap and malig hyp), PONV, analgesia
  5. Abdo: GORD, last meal time, chance of pregnancy
  6. PMH: diabetes, epilepsy, renal disease, thyroid, TIA/stroke, sickle cell
  7. DHx: allergies etc. and may need adjusting e.g. warfarin
  8. SH: smoking, alcohol, exercise tolerance (if not already covered)

General examination and thorough of relevant systems

138
Q

What if the pt has GORD?

A

The muscle relaxant could trigger it and risk aspiration, so RSI

139
Q

Does a pre-op assessment include consent?

A

No this is done in the surgical one

140
Q

How do you examine the mouth and neck in a pre-op assessment?

A

Ask the patient to open their mouth and assess:

Their degree of mouth opening (favourable if inter-incisor distance is above 3cm).

Their teeth, mainly do they have teeth? If so, what is their dentition like? Are any teeth loose?

Their oropharynx. Ask the patient to maximally protrude their tongue.

A Mallampati classification (Fig. 2), which correlates with difficulty of intubation, can be assessed.

Lastly, assess the neck. Ask the patient to flex, extend and laterally flex the neck to see their range of movement.

Then, ask the patient to maximally extend their neck and measure the distance between the thyroid cartilage and chin (the thyromental distance); if this is less than 6.5cm (~3 finger breadths), it indicates that intubation may be difficult.

141
Q

How many ASA grades are there?

A

6

142
Q

What is ASA grade 1

A

Healthy no disease

143
Q

ASA 2

A

Mild-mod systemic disease w/no functional limitation

144
Q

ASA 3

A

Severe systemic disease imposing functional limitation

145
Q

ASA 4

A

Severe systemic disease constant threat to life

146
Q

ASA 5

A

Not expected to survive without op

147
Q

ASA 6

A

Brainstem dead pt whose organs are being removed for donor purposes

148
Q

What is the suffix -E in ASA grading?

A

Emergency surgery

149
Q

How many surgical grades are there?

A

4

150
Q

What is the name of surgical grades 1-4?

A

1- minor

2- intermediate

3- major

4- major +

151
Q

Example of minor surgery

A

Excision of a skin lesion

152
Q

Example of intermediate surgery?

A

Inguinal hernia

Tonsillectomy

153
Q

Example of major surgery

A

hysterectomy, thyroidectomy

154
Q

Example of major + surgery?

A

Joint replacement, radical neck dissection

155
Q

What determines whether surgery is minor/major etc?

A

How much tissue injury occurs

156
Q

What investigations can be done pre-op? What does it depend on?

A

FBC, U&E, clotting, LFT, ABG

ECG

Pregnancy test

HbA1c IF DIABETIC AND NOT DONE IN LAST 3M

MRSA swab

None of these are really routine and depend on ASA and surgical grade. The most ‘routine’ one is PT.

157
Q

What are the fasting rules?

A

Food and milk, tea and coffee- 6h

Non clear fluid incl breast milk- 4h

Clear fluid- 2h

alcohol- 24hr

Can take tablets with <30mls water (?)

158
Q

Half life of water in the stomach?

A

10-20mins

159
Q

Half life of food in the stomach?

A

2.5-3h

160
Q

What if emergency surgery is required and the pt has had a meal?

A

RSI

161
Q

What does pre-oxygenation do?

A

Replaces FRC with O2

162
Q

What drugs are used in RSI?

A

Thiopentone (onset 15-30s)

Propofol (onset 30s)

Suxamethonium

163
Q

What extra technique is used in RSI?

A

Cricothyroid pressure to compress oesophagus until airway secured

164
Q

Is LMA or intubation used in RSI?

A

Intubation as it protects the airway

165
Q

How do you confirm the position of ETT?

A

EtCO2 (capnography)

Vapour on equipment

Chest expansion and auscultation

166
Q

USS uses what to create sound waves?

A

Pizoelectric crystal

167
Q

What tissues reflect ultrasound? How does it appear?

A

Bone

Hyperechoic (white)

168
Q

What tissues transmit ultrasound? How does it appear?

A

Vessels

anechoic (black)

169
Q

What tissues absorb ultrasound? How does it appear?

A

Soft tissue

isoechoic (grey)

170
Q

How do nerves appear on US? why?

A

Honeycomb- hyper and hypoechoic

171
Q

What tissues scatter ultrasound?

A

Irregular surface

172
Q

What three things do you need to adjust during USS?

A

Frequency (select the right probe)

Depth

Gain

173
Q

A ____ frequency probe is used for superficial (<6cm) structures (higher/lower)

A

Higher

174
Q

When adjusting depth on USS, where should the structure of interest appear on the screen?

A

3/4 from top

175
Q

What is gain in USS?

A

Like exposure on a photo

176
Q

On doppler USS, fluid moving towards the probe appears what colour?

A

Red

177
Q

What does acoustic shadowing artefact mean on USS?

A

Signal void behind the structure that strongly absorbs or reflects the US wave e.g. bone or stone

178
Q

What does acoustic enhancement artefact suggest on USS?

A

Increased echoes deep to structures that transmit sound very well e.g. fluid filled.

179
Q

What is a reverberation artefact on USS?

A

When you see more than one of something eg needle

180
Q

What is a comet tail artefact on USS?

A

White streaks seen when looking at calcific, crystalline or highly reflective objects

181
Q

What does FAST (scan) stand for

A

focused assessment with sonography for trauma

182
Q

What does a FAST scan look for?

A

Free fluid or air in the pelvis, pericardium or abdo

183
Q

What are the four echocardiography views?

A

Parasternal long axis

Parasternal short axis

Subcostal

Apical four chamber

184
Q

Parasternal long axis view shows which structures?

A

Both ventricles

LA

Aorta

(coronal view)

185
Q

Parasternal short axis shows which structures?

A

Both ventricles (axial view)

186
Q

Subcostal view shows what structures?

A

All four chambers axial view, possibly IVC by liver if turn the probe a bit

187
Q

Apical four chamber view shows which structures?

A

All four chambers axial view

188
Q

In the WHO surgical safety checklist, at what three points do people stop to check?

A

Before induction (with at least nurse and anaesthetist)

Before skin incision (plus surgeon)

Before pt leaves theatre

189
Q

How can you monitor temperature during an operation?

A

Oesophageal temperature probe through nose

190
Q

What are four ways to keep a patient warm in theatre?

A

Bear hugger

Warmed fluids/gases

Blankets

Ambient room temp

191
Q

What temperature of the patient do you aim for?

A

> 36C

192
Q

How do you reduce VTE and pressure sores?

A

Gel pads

TED stockings

DON’T routinely give tinz if they will be mobilising soon after

193
Q

Do you use opioids in day surgery?

A

Try to avoid as it makes them groggy

194
Q

Blood glucose normally _____ during surgery, even in non-diabetics

A

Rises

195
Q

BM should be taken when in diabetics?

A

Before, during and after the surgery

196
Q

In major surgery, what changes if they are diabetic?

A

First on list

Insulin is given during the op with insulin and potassium. two methods:

  1. Sliding scale (aka variable rate IVI insulin)
  2. Alberti regime
197
Q

What is sliding scale insulin regime?

A

Insulin administered separately to dextrose and potassium. The amount of insulin depends on blood glucose- keep adjusting

198
Q

What is the alberti regime?

A

Simultaneous administration of insulin, dextrose and potassium. The amount of insulin in the bag varies according to BM.

Pros- means insulin can’t be given without glucose

Con- frequent changes of bag

199
Q

In elective surgery for a diabetic patient what needs to be satisfactory beforehand?

A

HbA1c

200
Q

How should diabetic patients be managed in minor surgery?

A

If they are expected to E&D in <4hrs

Omit oral hypoglycaemic, given 1/2 or no insulin in morning.

Check BM during the op

Resume normal diet and insulin ASAP after

201
Q

What three things might affect the anaesthetic in a diabetic patient?

A

Increased risk of infection e.g. epidural abscess

Gastroparesis

Stiff neck/jaw due to glycosylation in TMJ or cervical spine

202
Q

If they are bradycardic and hypotensive during surgery what can you give?

A

noradrenaline (alpha and beta)

or ephedrine (alpha, beta1 and beta2 agonist, direct and indirect- releases noradrenaline- actions. IV.)

203
Q

What is the problem with ephedrine?

A

Tachyphylaxis- gets less effective the more it is given.

204
Q

If a patient is hypotensive only during surgery what can you give?

A

Metaraminol (99% alpha)

205
Q

What is the equation for oxygen delivery?

A

Cardiac output x conc. Hb x SpO2 x 1.34

206
Q

How does water enter cells?

A

Via sodium potassium channel

207
Q

How is water distributed within the body?

A

Total 42L

2/3 (28L) intracellular

1/3 (14L) extracellular- 25% intravascular (3.5L) and 75% interstitial (10.5L)

208
Q

Which fluid is most similar to water?

A

Dextrose- the sugar is metabolised so what is left is the same as water (same distribution) so 1L = about 100ml intravascular

209
Q

what happens if too much dextrose is given?

A

hyperglycaemia and dilutional hyponatraemia

210
Q

Which fluids are most similar to extracellular fluid? (go extravascular but not into cells})

A

Crystalloids

1L = 250ml intravascular

211
Q

What can too much sodium chloride fluid cause?

A

hyperchloraemic alkalosis

212
Q

What does Hartmann’s contain as well as sodium and chlorine?

A

lactate

Potassium

Calcium

213
Q

What is starling curve?

A

There is an optimal point of stroke volume (y axis) vs preload (x axis) - stretching the fibres by increasing preload initially = increased force of contraction, but after a point it is detrimental

214
Q

How can imaging help determine fluid status?

A

Oesophageal doppler- see stroke vol and cardiac output

215
Q

Two invasive ways to measure fluid status?

A

Art line

CVP (central venous pressure)- measures RV end diastolic pressure- assume equivalent to LV EDP and therefore volume

216
Q

Prescribing fluids should account for which two things

A

Maintenance

Perioperative loss

217
Q

L water required per day for maintenance?

A

2.5L

218
Q

How much Na2+ required per day for maintenance?

A

50-100mmol/1-2mmol/kg

219
Q

How much K+ required per day for maintenance?

A

40-80mmol/1mmol/kg

220
Q

If the gut is working how should you give fluids?

A

Oral

221
Q

If there are extra fluid losses, how do you know what to replace it with?

A

In general like with like, work out the volume and electrolytes lost

222
Q

How much sodium and Cl in NaCl 0.9%?

A

154mmol each per L

223
Q

How much sodium, Cl and K+ in Hartmann’s

A

131mmol Na2+

11mmol Cl-

5mmol K+

224
Q

What is a fluid challenge

A

Give a small bolus e.g. 250ml and see how they respond, if stroke volume increases they are still on the upwards bit of the Starling Curve so can keep giving more.

225
Q

What is a reversible way to test if they need a fluid challenge?

A

Passive leg raise to 45 degrees for 1min

Really need an art line to see the change in stroke vol

226
Q

A well 60kg woman NBM, needs maintenance for 24hrs, currently hydrated and no abnormal losses. What should you give?

A

Requires:

Water (3000ml)

Na (60 x 2 = 120mmol)

K (60 x 1 = 60mmol)

Option 1: 1L x 0.9% NaCl and 2L x 5% glucose with 20mmol K+ added to each bag of glucose. This gives 3000ml water, 154 Na and 40 K+

Option 2: 1L x Hartmann’s and 2L x 5% glucose + 20mmol K+ to each. This gives 3000ml water, 131 Na, 45 K.

There is no perfect solution

227
Q

How do you extubate?

A

Wait until breathing themself and then do it in theatre

228
Q

How do you remove LMA?

A

Disconnect when breathing, take to recovery, handover

229
Q

What are the levels of care?

A

0- ward

1- risk deterioration- ICU outreach or HDU

2- single organ/need detailed obs. ICU

3- ICU- ventilation/advanced resp support or >/= 2 organ systems

230
Q

What are the stages of recovery?

A

Stage 1- airway in

Stage 2- airway out then ward if 0. Spend about 20min in theatre recovery

231
Q

Drugs to treat shivering/tremors in post op?

A

Pethidine, ondansetron, anticholinesterases (e.g. propofol)

232
Q

Are fluids necessary post op?

A

Not if they can drink normally

233
Q

Does fluid provide calories?

A

No so if prolonged NBM give parenteral feed

234
Q

True or false oxygen always required after sedation?

A

Yes as hypoxaemic- venturi or simple face mask or nasal prongs

235
Q

What % get PONV?

A

about 30%

236
Q

What can help avoid PONV?

A

Avoid use of NO2

Total IV anaesthesia

237
Q

What drugs should be given post op

A

Analgesia- regular paracetamol, NSAIDs, weak opioid, strong opioid e.g. on ward paracet, naproxen, tramaxol and oxycodone

Antiemitic- ondansetron and cyclizine (combination therapy is effective)

Oxygen

‘Protective’- Laxative, PPI, Tinzaparin if will be immobile

238
Q

What are the four categories of CEPOD classification

A

Immediate

Urgent

Expedited

Elective

239
Q

What is CEPOD immediate?

A

life/limb/organ saving

resus and surgery simultaneous

Surgery within minutes

e.g. aneurysm rupture

240
Q

What is CEPOD urgent?

A

life/limb/organ threatening

Surgery w/in hours

e.g. bowel perf

241
Q

What is CEPOD expedited?

A

Within a day or two

e.g. large bowel obs, closed long bone fracture

242
Q

What is CEPOD elective?

A

Timing to suit hospital and patient e.g. joint replacement, cataract

243
Q

Treatment for aspiration during anaesthetic?

A

100% O2

Suction

Tracheal intubation and suction

Post op physio and O2

244
Q

Patient under anaesthetic has:

Increased HR

Decreased BP and SpO2

Acute decrease EnCO2

Millwheel murmur

A

Air embolism

245
Q

What procedures can cause air embolism?

A

Air in IV

C section

Central line

Use of high pressure gas e.g. laparoscopy

246
Q

Treatment air embolism

A

100% O2

ABC

Flood surgical site with saline

Aspirate with central venous catheter

Trendelenberg position (tilt table so head down), keeps the air at the RV apex not into circulation

? hyperbaric chamber

247
Q

Where does the air embolus go?

A

RA and RV

248
Q

Why does malignant hyperthermia occur (at a molecular level)

A

excessive release of Ca2+ from the sarcoplasmic reticulum of skeletal muscle

associated with defects in a gene on chromosome 19 encoding the ryanodine receptor

249
Q

When should you stop taking COCP before (elective) anaesthetic?

A

4w- VTE risk

250
Q

Why does laryngospasm occur

A

Airway irritation e.g. ETT when not deeply anaesthetised enough

251
Q

Signs laryngospasm

A

Airway obstruction

Paradoxical breathing in spontaneously breathing pt

252
Q

Rx laryngospasm

A

positive pressure with high flow o2

Deepen anaesthesia

Sux

253
Q

How should failed intubation proceed? stepwise

A
  1. Use video/bougie
  2. No more than 4 attempts
  3. LMA
  4. 1 attempt at fibreoptic ventilation over the LMA
  5. Wake patient and postpone surgery

MAKE SURE O2 AND ANAESTHESIA MAINTAINED THROUGHOUT, CAN ALWAYS REVERT TO BAGGING

254
Q

What about a ‘can’t intubate can’t ventilate’ situation

A

Needle or surgical cricothyroidotomy

255
Q

What triggers malignant hyperthermia?

A

Volatiles

Sux

256
Q

What is the pathophys of malig hyperthermia

A

Loss of normal calcium homeostasis in skeletal muscle cells. Hypermetabolsim leads to hypoxia, hypercapnia, hyperthermia and acidosis.

Genetic defect in ryanodine receptor (chr 19)

257
Q

Inheritance of malignant hyperthermia gene

A

Autosomal dominant

258
Q

Rx malig hypertherm

A

Remove trigger

100% O2

Cooling

Dantrolene IV (1mg/kg up to 10) inhibits Ca2+ release in muscle

to ICU

259
Q

How can you test for malig hypertherm

A

Muscle biopsy

260
Q

Why does suxamethonium apnoea happen?

A

Genetic, lack enzyme to metabolise sux so it lasts longer

261
Q

Sux apnoea could potentially cause what

A

awareness

262
Q

Rx sux apnoea

A

Maintain sedation and ventilate them on ICU until it wears off

263
Q

sux apnoea is also linked to failure to metabolise which non-depolarising muscle relaxant?

A

Mivacurium

264
Q

Signs of anaphylaxis during anaesthetic?

A

Rash

Wheeze

Increased ventilatory pressure

Drop in BP that is unresponsive to Rx

Angioedema

Tachy/bradycardia

Dysrhythmias

265
Q

Rx anaphylaxis during anaesthetic

A

Remove stimulus

ABC, 100%O2

ETT

Adrenaline

Fluid

Chlorpheniramine (antihist) 10mg

Hydrocortisone

Salbutamol

266
Q

SVT Rx in anaesthetic

A

Valsalva manoeuvre

Ice cold stimulus to neck

Carotid massage

Drugs

4th Year ACC (9 decks)

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