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Flashcards in anaesthetics Deck (172):
1

where does general anaesthetic provide sensensibility

whole body
implies loss of consciousness and global lack of awareness

2

where does regional anaesthetic provide sensensibility

an area or region of the body
Nerve and plexus blocks

3

where does local anaesthetic provide sensensibility

local relevant area - direct to tissue being anaesthetised

4

what type of anaesthetics are spinal/ epidurals

regional

5

what is the triad of anaesthetics

hypnosis
analgesiia
relaxation (skeletal muscle)

6

what does hypnosis mean

unconscious

7

what is the aim of pain relief

removal of perception of unpleasant stimulus

8

what are some problems of balanced anaesthesia

¥ Polypharmacy - Inc chance of drug reactions / allergies
¥ Muscle relaxation - requirement for artificial ventilation, means of airway control
¥ Separation of muscle relaxation & hypnosis – awareness – patients awake from wrong dose yet paralysed so unable to communicate

9

what are the principles of balanced anaesthesia

¥ Different drugs to do different jobs
¥ Titrate doses separately & therefore more accurately to requirements
¥ Avoid overdosage
Control over individual components of the triad

10

how are general anaesthetics given

inhaled (maintenance) or IV (induction)
(Inhalational agents dissolve in lipid membranes Direct physical effect
Intravenous agents -allosteric binding e,g. GABA receptors also open chloride channels)

11

what ion channel is sully targeted in GA and why

chlorine
Hyperpolarise neurones = Less likely to “fire” (suppress excitatory synaptic activity)

12

after GA what functions are lost first

most complex then primitive lost later

13

are reflexes spared in GA

yes

14

what must be managed when the patient is under GA

airway and cardiovascular

15

what is the name of the pump system that allows accurate infusion to achieve specific blood or brain concentrations of agents using complex pharmacokinetic algorithms

target controlled infusion (TCI)

16

what is a problem with IV anaesthesia and how is this controlled

can't measure drug concentration in real time
Use computers to calculate a guess

17

are IV anaesthesia drugs fat or water soluble

fat - cross membrane quickly

18

what is the rapid recovery form IV anaesthesia due to

drug leaving the circulation and moving to other parts of the body eg muscle and viscera organs

19

list some anaesthetics that are given IV

thiopentone
propofol

20

list some anaesthetics that are inhaled

halogenated hydrocarbons

21

which organ does the uptake and excretion of inhaled anaesthestics

lung
(concentration gradient - lungs > blood > brain
cross alveolar BM easily
arterial concn equates closely to alveolar partial pressure)

22

what is the MAC (mean alveolar concentration) a measure of (inhaled anaesthetic)

measure of potency
low number = high potency
(less concentration to produce the same affect)

23

why are really high doses of inhaled anaesthesia given for induction

gas down the concentration gradient in to the patients blood and finally brain to achieve a high enough partial pressure there to produce unconsciousness

24

what is the main role of inhalation agents

extension or continuation of anaesthesia

25

what are the central CVS effects of GA

depress cardiovascular centre
reduce sympathetic outflow
negative inotropic/chronotropic effect on heart
reduced vasoconstrictor tone → vasodilation

26

what do anaesthetics do to respiratory system

depress
Reduce hypoxic and hypercarbic drive
Decreased tidal volume & increase rate
paralyse cilia

27

what is the exception to all anaesthetics being CVS depressant

ketamine

28

why does CO fall under anaesthesia

vasodilation reduces venous return to the heart

29

what are the differences between anaesthetic and opiate respiratory depression

opiate - preserves tidal volume, low respiratory rate
anaesthetic - reduced tidal volume, high respiratory rate

30

why do some post op patients need anaesthetics for several days

greatly reduced lung volume can interfere with ventilation/ perfusion matching

31

what are indications for muscle relaxants

ventilation & Intubation
when immobility is essential - microscopic surgery, neurosurgery
body cavity surgery (access)

32

list some problems with muscle relaxants

awareness
incomplete reversal → airway obstruction, ventilatory insufficiency in immediate post op period
apnoea = dependence on airway & ventilatory support

33

why is anaesthetic given intra-operatively

Prevention of arousal (pain)
Opiates contribute to hypnotic effect of GA
Suppression of reflex responses to painful stimuli (hypertension, tachycardia)

34

which system is relatively spared in regional anaesthetic compared to general

respiratory

35

what are the 7 steps in the process of anaesthesia

pre-opeartive assessment
preparation
induction
maintenace (monitoring)
emergence
recovery
post operative assessment

36

what is the time of onset for IV induction of anaesthetic

one arm brain circulation - 20s

37

do you remain conscious with local and regional anaesthetics

yes
(CVS derangement proportional to size of area)

38

what is a limiting factor for use of local anaesthetic

toxicity

39

why is toxicity a risk factor in local anaesthetics

absorption > rate of metabolism = high plasma levels

40

what things does the toxicity of LA depend on

dose used
rate of absorption (site dependant - perfusion)
patient weight
drug ( bupivacaine > lignocaine > prilocaine )

41

list some signs and symptoms of local anaesthetic toxicity

Circumoral and lingual numbness and tingling
Light-headedness
Tinnitus, visual disturbances
Muscular twitching
Drowsiness
Cardiovascular depression
Convulsions
Coma
Cardiorespiratory arrest

42

why are some areas easier to block with LA than others (differential block)

different nerve fibre types - thickness and myelination

43

what makes pain fibres easier to block with LA than motor fibres

thinner and less myelinated

44

during anaesthesia what is a cough depednent on

abdominal muscles (expiratory function)

45

during anaesthesia which is more spared, inspiration or expiration

inspiration (instercostaals and accessory muscles higher root nerves)

46

list some considerations in the pre-operative preparation of GA

Planning - checklist - Right patient, right operation
Right (or left) side
Pre-medication (sedatives/ analgesia)
Right equipment, right personnel Drugs drawn up
IV access - Monitoring

47

what agents may be used for the IV induction of anaesthesia

Propofol - standard, less hangover, quick, less side effects
thiopentone - barbiturate, maternity hospital

48

why do you need good airway control in GA

apnoea very common

49

what drug may be used for the gaseous induction of anaesthesia

sevoflurane

50

in what patients is gaseous induction of anaesthesia better than gaseous

younger children
IV drug users

51

what is the triple airway manoeuvre in airway maintenance

head tilt, chin lift, jaw thrust

52

what manoeuvre can solve an airway obstruction but to loss on tone from the tongue

jaw thrust

53

what is the minimum monitoring in anaesthetics

SpO2, ECG, NIBP, FiO2, ETCO2
(temperature, urine output)

54

what is a common post operative side effect of anaesthesia

nausea and vomitting

55

what are different planes of anaesthesia

analgesia
excitation
anaesthesia
overdose

56

list some different methods of airway management

Oropharyngeal airway (Guedel)
Laryngeal mask
endotracheal intubation

57

which patents can tolerate a Oropharyngeal airway (Guedel

unconscious

58

what is a laryngeal mask airway

Cuffed tube with ‘mask’ sitting over glottis
Maintains, but does not protect the airway

59

what reflex must be abolished before endotracheal intubation

laryngeal

60

what is the most common airway complication

Ineffective Triple Airway Manoeuvre

61

list some complications of airway management

Ineffective Triple Airway Manoeuvre
Airway device malposition or kinking
laryngospasm
aspiration - gastric contents, blood, surgical debris

62

what is the only thing that protects the airway from contamination

cuffed tube in the trachea

63

list reasons for intubating

Protect airway from gastric contents
Need for muscle relaxation artificial ventilation
Shared airway with risk of blood contamination- e.g. tonsillectomy in ENT
Need for tight control of blood gases
Restricted access to airway - e.g. Maxillo-facial surgery

64

what are anaesthetic risks to an unconscious patient

“Airway, Airway, Airway”
Temperature
Loss of other protective reflexes - eg corneal, joint position (dislocate shoulder)
Venous thromboembolism risk
Consent & Identification
Pressure areas

65

what are the main complications of anaesthesia

airway, breathing, circulation
related to techniques. position
awareness

66

what are some of the anaesthetists roles pre-op

Assess patient as whole for procedure
Identify high risk - high morbidity and mortality
Optimise patients to minimise risk
Inform and support patients decisions
Consent from patient

67

should you continue a patients medications before an operation

mostly
especially Inhalers, Anti-anginals, Anti-epileptics,
Most cardio/ respiratory medications

68

what medications should be discontinued before an operation

anti-diabetic medication
anticoagulants (if safe to stop)

69

what is the point in an anaesthetists pre-op assessment

Reduces;
Anxiety
Delays Cancellations (resources)
Complications Length of stay Mortality (well planned)

70

what things may be asked in the history for an anaesthetist's pre-op assessment

Known co-morbidities (Severity, Control)
Unknown co-morbidities - (Systemic enquiry, Clinical examination)
Ability of withstand stress - Exercise tolerance, Reason for limitation, Cardio-respiratory disease focus
Drugs and allergies - DDIs
Previous surgery and anaesthesia reaction

71

describe the ASA grading of surgical patients

ASA1 - Otherwise healthy patient
ASA2 -Mild to moderate systemic disturbance
ASA3 - Severe systemic disturbance
ASA4 - Life threatening disease
ASA5 - Moribund patient (ASA6 Organ retrieval)

72

list some risk assessment tools for pre-op anaesthesia

GUPTA perioperative cardiac risk
Surgical outcome risk tool American college of surgeons surgical risk calculator
STOP-BANG questionnaire P-POSSUM/ CR-POSSUM/ Q-POSSUM/ V-POSSUM

73

what things are considered in the cardiac risk index for anaesthesia pre op assessment

High risk surgery Ischaemic heart disease
Congestive heart failure Cerebrovascular disease
Diabetes Renal failure

74

what is the METS way of measuring exercise tolerance

Without getting breathless -
Walk around the house- 2 METS
Do light housework - 3 METS
Walk 100-200 metres on the flat- 4 METS
Climb a flight of stairs or walk up a hill - 5 METS
Walk on the flat at a brisk pace - 6 METS
Play golf, mountain walk dance, or any form of exercise - 7 METS
Run a short distance - 8 METS
Do either strenuous exercise or heavy physical work - 9 METS
(15% reduction in mortality risk per MET score point)

75

list some things a patient can do pre-op to improve their outcomes

Optimum medical control - Hypertension, Ischaemic heart disease, Heart failure,Asthma, COPD, Epilepsy, Diabetes
Lifestyle – smoking, alcohol, obesity,
exercise - improve fitness

76

what are the 0-3 levels of care

0 - primary care
1- Ward-based
2- High dependency unit – single organ support
3- ITU – multi-organ support

77

where is the only place invasive ventilation can be done

ITU

78

what is the main difference in the need for HDU and ITU

HDU -single organ support
ITU - multiple organ support

79

what are the nice guidelines for Na+ fluid replacement

1 – 2mmol/kg/day

80

what are the nice guidelines for K+ fluid replacement

0.5 – 1mmol/kg/day

81

what are the nice guidelines for max fluid replacement

25-30ml/kg/day

82

what are the nice guidelines for glucose replacement

50-100g/day

83

how would you support GI failure

unblocking any blockages
stenting
TPN with a nasogastric tube.

84

how would you support renal failure

dialysis

85

how would you support pancreatic failure

support diabetes, digestive enzyme control

86

what are the outcomes of liver failure

self limiting
transplant
die

87

what GCU will be intubated below

8

88

how would you support brain failure

Ensure the brain is getting O2 and CO2 clearance by vasodilation/ vasopressin, drugs to stop vasospasm, manage raised ICP, sedate, moderate temperature for tissue recovery.

89

what are the fatality rates of ITU

25-30%

90

what are benefits of a tracheostomy over a endotracheal tube in ITU

inserted in neck so don't need sedation of gag reflex

91

what are the 2 jobs of the lungs

get O2 in
get CO2 out

92

which respiratory failure is more common in ITU

type 1
(easier to treat - give O2)

93

what is the most sensitive marker of a deteriorating patient

increasing RR - tachypnoea

94

what 4 was can oxygen be given in critical care

High-flow nasal cannula. – max 4l a min
Facemask – 10L/min
CPAP.
Intubation and invasive ventilation.
ECMO.

95

what are peoples normal o2 sats

99% on 21% O2

96

why do people find high flow nasal cannulas uncomfortable

cold dry air blasted up nose

97

what is the best treatment of type 2 respiratory failure in critical care

invasive ventilation

98

what does positive pressure from ventilators do to the lungs

ventilators opens lung up so blood can be oxygenated
(also cause lung damage so shorten time)

99

why is CO hard to measure

difficult to measure SV

100

what drugs speed up the heart

chronotropes

101

what drugs affect the contractility of the heart

inotropes (beta1 agonists)

102

what drugs affect the pre load or after load of the heart

pre - fluids
after - vasopressors

103

what type of drugs are vasopressors

alpha-1 agonists - constrict blood vessels (mostly veins) - noradrenaline

104

give an example of a vasopressor drug

noradrenalien/ adrenaline
alpha-1 agonist

105

where are central lines most commonly placed and why

R interval jugular vein - goes straight to SVC

106

what is a benefit of central lines over peripheral cannulas

can be left in for 7-10 days but a cannula only 3 days

107

what is lactate a marker of

tissue of hypo perfusion (produced in anaerobic metabolism)
>2 abnormal, >4 really bad

108

what is pain

an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage

109

what is the number 1 disease for years lost to disability worldwide

lower back pain

110

what are the physical benefits or treating pain

Improved sleep, Better appetite
Better movement Fewer medical complication e.g. heart attack, pneumonia

111

what are the psychological/social benefits of treating pain

Reduced suffering
Less depression, anxiety
better family ember
able to keep working
lower health costs
contribute to community

112

what is the difference between acute and chronic

Acute:Pain of recent onset and probable limited duration
Chronic: Pain lasting for more than 3 months, lasting after normal healing, often with no identifiable cause
Can get acute on chronic (flare up )

113

what are the 3 most common classifications for pain

acute vs chronic
nociceptive vs neuropathic
cancer (progressive) vs non- cancer

114

how long does chronic pain last

> 3 months

115

what is the difference between nociceptive and neuropathic pain

nociceptive - damage to afferent nerves
neuropathic - nervous system damage or abnormality

116

what type of pain has a physiological protective function

nociceptive

117

how is nociceptive pain commonly described

Sharp ± dull, Well localised (or visceral)

118

how is neuropathic pain commonly described

Burning, shooting ± numbness, pins and needles, Not well localised (all over)

119

give examples of neuropathic pain

nerve trauma
diabetic pain (neuropathy), fibromyalgia
chronic tension headache (dysfunction)
very common after thoracic surgery (intercostal nerves)

120

what are the pathological mechanisms involved in neuropathic pain

Increased receptor numbers – amplification
Abnormal sensitisation of nerves –Peripheral or Central – ie light touch
Chemical changes in the dorsal horn – neurotransmitters, neuromodulators, noradrenaline, serotonin, Ca
Loss of normal inhibitory modulation

121

what are the 4 steps of pain physiology

1 peripheral tissue injury
2 travels up spinal cord (spinothalamic)
3 brain - thalamus secondary relay station, pain perception in cortex
4 modulation - descending pathway from brain to dorsal horn to decrease signal

122

what chemicals do tissues release in response to pain

prostaglandin
substance P

123

what are pain receptors called

nociceptors

124

what type of nerves do pain signals travel in

A(delta)
C fibres

125

what treatments can be given to target the peripheral tissue injury (pain)

RICE (rest, ice, compression, elevation),
NSAIDs
LA (damp down response – C fibres, Aδ

126

what is the 1st and second relay station for pain

1st - dorsal horn
2nd - thalamus

127

where do pain fibres cross the spinal cord

at the level they enter

128

describe the route of the 1st and 2nd nerve in the physiology of pain

1st - tissue to dorsal horn
2nd - opposite side of spinal cord

129

what treatments can be used to target the spinal cord in pain management

acupuncture, massage, TENS
Local anesthetics, opioids, ketamine

130

where does pain perception occur

cortex of brain

131

what is the gate theory of pain

Gate theory of pain - painful signal travels into dorsal horn interneuron can be switched off - this can be stimulated by Abeta nerve and stop pain firing

132

what treatments target the brain for pain management

paracetamol, opioids, amitriptyline, clonidine, psychological (cognitive behavior therapy)

133

what is the physiology of modulation of pain

Descending pathway from brain to dorsal horn
Usually decreases pain signal

134

list 2 classes of simple analgesics

paracetamol
NSAIDs

135

what are advantages of paracetamol

Cheap, safe, Can be given orally, rectally or intravenously

136

what are disadvantages of paracetamol

liver failure in overdose

137

what is the antidote to opiates

naloxone

138

give examples of mild opiods

codeine
dyhydrocodeine

139

give examples of strong opiods

Morphine, Oxycodone, Fentanyl

140

what are advantages of mild opiates

Cheap, safe, Good for mild-moderate acute nociceptive pain,
Best given regularly with paracetamol (synergism)

141

what are disadvantages of mild opiates

Constipation, Not good for chronic pain

142

what are advantages of strong opiates

Cheap
generally safe
Can be given orally, IV, IM, SC
Effective if given regularly
Got an antidote.
Good for Mod-severe acute nociceptive pain (e.g. post-op pain), Chronic cancer pain

143

what are disadvantages of strong opiates

Constipation
Respiratory depression in high dose
nausea,
addiction (Controlled drug,
not good for neuropathic

144

are opiates good for neuropathic pain

no

145

what is tramadol

(Mixed opiate and 5HT/NA reuptake inhibitor)
(plus inhibitor of serotonin and noradrenaline reuptake (modulation)

146

what are advantages of tramadol

Less respiratory depression, can be used with opioids and simple analgesics, Now a controlled drug

147

what is amitriptyline

tricyclic antidepressant (TCA

148

what are advantages of amitriptyline

cheap, safe in low dose, good for neuropathic pain, also treats depression, poor sleep

149

what are disadvantages of amitriptyline

Anti-cholinergic side effects (e.g. glaucoma, urinary retention)

150

what anticonvuslantsa re used for pain manangemtn

gabapentin (Neurontin)
sodium valproate (epilim)
carbamazepine (tegretol)
membrane stabilisers – reduce abnormal firing of nerves (Good for neuropathic pain)

151

what is ketamine

NMDA Receptor antagonist

152

how may LA be administered

Epidural
Intrathecal
Wound Catheters Local Infiltration of wounds
Nerve Plexus Catheters (brachial/ femoral/ sciatic)

153

name a topical agent used to manage neuropathic pain

capsaicin

154

list ways to assess pain

Verbal rating score – no, mild, moderate, severe, excruciating
Numerical rating score – 0-10 – most people don’t like numbers, hard to interpret
Visual analogue scale – line with scale
Smiling faces – paediatric
Abbey pain scale - confused patients, looks at pain and patient behaviour

155

list some non-drug methods of managing pain

Physical - Rest, ice, compression, elevation
Surgery
Acupuncture, massage, physiotherapy
Psychological- Explanation – expected, Reassurance
Counselling – positive psychology

156

where on the WHO pain ladder do you start with mild pain

Start at Bottom of Pain Ladder

157

where on the WHO pain ladder do you start with moderate pain

Bottom of Pain Ladder plus Middle Rung

158

where on the WHO pain ladder do you start with severe pain

Bottom of Pain Ladder plus Top of Ladder.
Miss out the middle

159

is it ok to start at the top of the WHO pain ladder

severe/ unbearable pain

160

would you stop NSAIDs or paracetamol first

NSAIDs as more adverse effects

161

what type of pain is the WHO ladder for

nociceptive NOT neuropathic

162

what is step 1 of the WHO pain ladder

aspirin, NSAIDs, paracetamol

163

what is step 2of the WHO pain ladder

mild opiods eg codeine

164

what is step 3 of the WHO pain ladder

strong opiods e.g. morpheine

165

what does the RAT assessment stand for

R - recognise
A- assess
T - treat

166

what drugs should be used for neuropathic pain

Amitriptylline, Gabapentin, Duloxetine

167

what is involved is the 'Recognise' of RAT assessment

Does the patient have pain? Ask, Look (frowning, moving easily, sweating)
Do other people know the patient has pain? Other health workers, Patient’s family

168

what is involved is the 'Assess' of RAT assessment

Severity - pain score at rest and with movement, how is pain affecting the patient? Can they move, cough, work
Type – acute, chronic, cancer, non-cancer, nociceptive, neuropathic (burning/ shooting, phantom limb, pins and needles, numbness)
Other factors – other illnesses (physical), lack of social support, home circumstances, work (social), anger, anxiety, depression (psychological)

169

how should you treat moderate nociceptive pain

Paracetamol (± NSAIDs)

170

how should you treat mild nociceptive pain

Paracetamol (± NSAIDs) + codeine/ alternative

171

how should you treat severe nociceptive pain

Paracetamol (± NSAIDs) + morphine

172

what should you always remember to do when treating your patient for pain

Reassess the patient: Is your treatment working?
Are other treatments needed? Up or down pain ladder