anaesthetics

Question 1

structure for dealing with anaesthetic related exam question?

Answer 1

A: airway - patent, or obstructed? do they need an ETT or can they sustain own airway - Mask

B: breathing: breathing on their own? maintained - - mask or LMA.
need mechanical ventilation: ETT

C: CVS - anaesthetic drugs - decrease CVS + resp - therefore monitor

Question 2

LMA means?

Answer 2

laryngeal mask airway

Question 3

ETT means?

Answer 3

endotracheal tube

Question 4

3 steps prior to anaesthetic + op?

Answer 4

considerations

pre-op assessment

optimising

Question 5

Considerations (pre-op)

Answer 5

Pt: risk - assess, high risk, minimise risk.
Info: informed consent - reduce anxiety etc

surgery: deal with the stress, blood loss, fluid shifts,

anaesthetic - ADRs, coma, CVS,CNS, resp problems

Question 6

pre-op assessment

Answer 6

hx - known + unknown co-morbs - severe? control.
d+a
prev surg + prev anaesthetic problems

ex - ASA grading

exercise tolerance:
METs

investigations

Question 7

exercise tolerance within pre op assessment?

Answer 7

MET - metabolic equivalents

2: walk around house
5: walk up hill , stairs
9: strenuous exercise

Question 8

point of investiigations in pre-op assessment

Answer 8

establish baseline for post op monitoring.

Question 9

aspects of optimisation

Answer 9

• optimise: IHD, DM, COPD, HTN, asthma, epilepsy
• do not stop
  anti epileptics, inhalers,
  anti-anginas
• stop DM meds - pts done 1st
• anticoagulants stopped if secondary

Question 10

triad of anaesthesia

Answer 10

hypnosis (unconscious)

analgesia

muscle relaxants

Question 11

if muscle relaxants used must have?

Answer 11

mechanical ventilation - ETT

and hypnosis - unconscious pt

Question 12

Rapid onset IV induction agent?

Answer 12

propofol - readily distributes, fat soluble and crosses BBB

Question 13

inhaled agent - for maintenance?

Answer 13

halogenated hydrocarbons - want a low MAC - minimum alveolar concentration - potent drug

Question 14

common side effects of anaesthetic drugs - what should always be monitored

Answer 14

• CVS: cause vasodilation (decreased TPR + BP) & venodilation (decreased venous return + CO)
• resp: increased RR + decreased tidal volume/
  reduce hypoxic and hypercapnic drive

Question 15

what anaesthetic drug doesn’t depress the CVS + resp systems?

Answer 15

ketamine

Question 16

indications for muscle relaxants

Answer 16

• neurosurgery (tight control of sats)
• open cavity surgery - laparotomy
• microscopic surgery
• when ventilation + intubation are required

Question 17

local anaesthetic - limiting factor

Answer 17

toxicity

Question 18

aspects to help induction

Answer 18

quiet room /anaesthetic room

noise can trigger laryngospasm

Question 19

how do you monitor consciousness?

Answer 19

loss of verbal contact 
lack of movement 
resp pattern 
EEG 
stages of anaesthesia

Question 20

1st stage of anaesthesia?

Answer 20

stage 1: induction - between induction of agents + loss of consciousness
can still be communicating

Question 21

2nd stage of anaesthesia?

Answer 21

excited + delirious - resp + CVS become irreg.,

rapidly acting drugs are used to minimise the time spent in this stage

Question 22

3rd stage of anaesthesia?

Answer 22

surgical anaesthesia - skeletal m relaxes, resp depression,

Question 23

4th stage of anaesthesia?

Answer 23

overdose

severe brainstorm/medulla depression - resp ceases, potential cvs collapse

Question 24

simple airway management options?

Answer 24

• face mask (triple airway manoeuvre)
• oropharyngeal airway (feudal) must be unconscious
• nasopharyngeal airway

Question 25

advanced airway management?

Answer 25

• LMA: supraglottic - therefore does not protect the airway from aspiration or laryngospasm (where the vocal cords adduct)

Question 26

ETT allows for…

Answer 26

protection from gastric contents

muscle relaxants to be used

neurosurg - tight blood gas control

Question 27

airway complications?

Answer 27

aspiration

airway collapse - laryngospasm

Question 28

risks of unconsciousness?

Answer 28

hypothermia 
pressure sores 
hypoxia 
loss of protective reflexes 
VTE 
airway collapse

Question 29

monitor what?

Answer 29

Sp02, ECG,BP, Fi02, ETCO2, resp parameters, agent monitoring, temp, Urine output, NMJ, invasive venous / arterial monitoring, ventilator disconnect

Question 30

emergence substance?

Answer 30

sevoflurane

gas - commonly used in paeds + emergencies

Question 31

types of pain?

Answer 31

chronic (>3wks), + acute

cancer + non cancer

Question 32

nociceptive pain is?

Answer 32

obvious tissue injury or illness, normally well localised

Question 33

neuropathic pain description?

Answer 33

damaged or abnormal nervous system - described as burning, numbness, not well localised

Question 34

neuropathic pain tx?

Answer 34

does not respond to WHO pain ladder

Question 35

example of causes of neuropathic pain

Answer 35

nerve trauma
dm
fibromyalgia
chronic tension headache

Question 36

physiology of peripheral pain

Answer 36

tissue injury –> release of prostaglandin - stimulation of nociceptors - signal A delta + C fibres to spinal cord

Question 37

spinal cord pain physiology

Answer 37

dorsal horn (1st delay) fibres synapse - decuss at that level. ascend spinothalamic tract

Question 38

brain physiology of pain

Answer 38

thalamus –> cortex - pain perception

Question 39

physiology of pain modulation

Answer 39

descending pathway - gate theory: activation of inhibitor interneurone between nociceptor fibres and large distractive nerve fibre

Question 40

spinal cord pain tx

Answer 40

local anaesthetic
opioids
ketamine

Question 41

WHO pain ladder

Answer 41

1. non opioid - aspirin, paracetamol
2. weak opioid: codeine
3. strong opioid: morphine,fentanyl