Anaesthetics Flashcards
(266 cards)
1
Q
Three things needed in anaesthetic?
A
Amnesia
Akinesis
Analgesia
+not harmful to patient
2
Q
What is meant by amnesia for an anaesthetic?
A
No recall/response to noxious stimuli
Unconscious
3
Q
What are the three steps of an anaesthetic?
A
Induction
Maintenance, monitoring
Reversal
4
Q
What is induction and how long does it take and last?
A
Inducing LOC
Takes 10-20 secs and lasts 4-10mins
5
Q
What are the 4 induction agents?
A
- Propofol
- Thiopentone
- Ketamine
- Etomidate
6
Q
What is the most commonly used induction agent?
A
Propofol 95%
7
Q
Propofol dose
A
1.5-2.5mg/kg
8
Q
Two benefits of propofol
A
Suppresses airway reflex so broncho/laryngospasm unlikely
Low PONV
9
Q
4 disadvantages of propofol
A
Lowers HR and BP
Painful to inject as thicc
Involuntary movements
Hiccups
10
Q
Thiopentone dose
A
4-5mg/kg
11
Q
Thiopentone class
A
Barbiturate
12
Q
Thiopentone is mainly used when?
A
RSI (fast acting)
13
Q
Benefit of thiopentone
A
Anti-epileptic, protects brain
14
Q
5 disadvantages thiopentone
A
Lowers BP increases HR
Rash
Bronchospasm
If intra-arterial –> thrombosis and gangrene
Contraindicated in porphyria
15
Q
Ketamine dose
A
1-1.5mg/kg
16
Q
What does ketamine cause
A
Dissociative anaesthesia
Anterograde amnesia and profound analgesia
17
Q
What is ketamine best used for
A
Sole anaesthetic in short, painful procedure
18
Q
Ketamine benefit?
A
Bronchodilation
19
Q
4 ketamine disadvantages
A
Slow onset
Increases HR and BP
N&V
Emergence phenomenon/delirium (esp in young women)
20
Q
Etomidate dose
A
0.3mg/kg
21
Q
Etomidate class
A
steroidal
22
Q
Etomidate three benefits
A
Rapid onset
Haemodynamic stability (good in e.g. HF)
Least likely to = hypersens reaction
23
Q
4 disadvantages etomidate
A
Pain to inject
Spont movement
Adrenal-cortico suppression (needed to maintain BP)
High incidence PONV
24
Q
What are two ways you can maintain anaesthesia?
A
Propofol infusion (total IV anaesthesia)
Inhalation agents (aka volatiles, vapours)
25
What are the four inhalation agents?
Isoflurane 1.15%
Sevoflurane 2%
Desflurane 6%
Enflurane 1.6%
26
Benefit of isoflurane
Least effect on organ blood flow
27
Benefit of sevo
sweet smell
gas induction e.g. children
28
Benefit of desflurane
low lipid solubility
rapid onset and offset
long ops
29
Drawback of desflurane
Airway irritant- only use if intubated
30
What controls the concentration of volatile agent?
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.
31
How do you get an idea of the brain concentration of the volatile agent?
End tidal measurement e.g. EnSevo
32
What is the benefit of using NO2?
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
33
What is an SE of NO2?
PONV
34
What is MAC?
Minimum alveolar concentration
The conc of the vapour that prevents the reaction to a standard surgical stimulus in 50% subjects
35
Is analgesia given before or after the induction agent?
Before so it has time to work
36
When is analgesia required in an operation?
All the time including airway insertion and post-op
37
What analgesia is given intra-op?
Short acting opioid
38
three short acting opioids that are given intra op?
Remifentanyl
Alfentanyl
Fentanyl
39
Which opioid is most often given intra-op?
Fentanyl (90%)
40
Which opioid is more short acting?
Alfentanyl
41
How is remifentanyl given?
IVI
42
How do LAs work?
Inhibit sodium channel in nerve axon
43
When should you not use LA with adrenaline?
Penile block or digits
44
What 2 types of chemical are LAs?
Esters or amides
45
Name two topical analgesics
EMLA (50/50 lignocaine and prilocaine)
Ametop (tetracaine 4% gel)
46
Max dose lignocaine, with and without adrenaline
3mg/kg
7mg/kg with adrenaline
47
Max dose bupivacane , with and without adrenaline
2 and 2mg/kg
48
Max dose prilocaine, with and without adrenaline
6mg/kg and 9mg/kg
49
A 1% solution has how many mg/ml
10
50
Symptoms LA toxicity
Perioral numbness and tingling
tinnitus
Seizure
Arrhythmia
51
How do you treat LA toxicity?
Anaesthetic emergency!
ABCDE
100% O2
Stop surgeon, send for help
Crash trolley
Intralipid to soak up
Start IV fluids
52
Other than giving too much, how can LA toxicity occur?
Injecting into a vessel
53
What analgesic do you give intra and post-op?
Long acting opioids e.g. morphine, oxycodone, pethidine
54
How many days to become dependent on long acting opioid?
17
55
Under what weight (of a patient) do you reduce the dose of paracetamol?
45kg
56
Can you give tramadol with morphine?
yes
57
Can you give dihydrocodeine with morphine?
No
58
What is the dose of ketamine for analgesia?
0.25-0.5mg/kg
59
What is the anaesthetic way of assessing pain?
RAT
Recognise
Assess
Treat
60
What is allodynia?
Normal stimulus is painful
61
What is nociceptive pain?
Due to tissue injury, is protective
62
What is neuropathic pain?
Not protective
63
What is chronic pain? time scale
>3m
64
When might you get hypo/hyperalgesia?
Peripheral neuropathy
Fibromyalgia
65
describe the pain pathway
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)
66
Does the WHO analgesic ladder apply in severe acute nociceptive pain?
Reverse it
67
In the 'assess' part of RAT what 4 features of the pain do you need to determine?
Cancer/non-cancer
Noci or neuro
Acute/chronic
Other factors
68
Patient controlled analgesia is usually what drug?
IV morphine
69
What four structures does an epidural needle pass through to get to the epidural space?
Skin
SC fat
Supraspinous ligament
Ligamentum flavum
70
What space does a spinal block go into?
Sub arachnoid space
71
What does subarachnoid space contain?
CSF
72
What structures does a spinal block needle pass through?
Skin
SC fat
Supraspinous ligament
Ligamentum flavum
Epidural fat
Dura
Arachnoid
73
How long does an epidural take to work?
15-30m
74
What is in the epidural space?
Fat and blood vessels
75
What level do you put in an epidural?
Depends on op
76
Risk damage to SC above what level epidural?
L1
77
An epidural is put into what level during labour?
L2-S2
78
At what level does the subarachnoid space end?
S1
79
At what level does the spinal cord end?
L1/L2
80
At what level does the epidural spac end?
Sacrococcygeal hiatus
81
What level does a spinal go into?
L3-L5 (in SA space but below SC)
82
What is in a spinal block?
Usually LA and opioid
83
How long does a spinal take to work?
5-10min
84
Does a spinal also block motor?
Yes
85
How do you test a spinal has worked?
Cold spray as spinothalamic tract= pain and temp
86
What score is used to test motor block in a spinal anaesthetic?
Bromage scale
87
What is a side effect of spinal block?
Decreased BP (decreased sympathetic NS)
88
Spinal vs epidural:
Which is a single injection, which has a cannula for continuous infusion?
Spinal is single injection
Epidural continuous.
89
How is a nerve/plexus block given?
US guided
LA around the nerve (not into a vessel!)
Use cold spray to check
90
How long does a regional block last?
12-24hr
91
Is akinesis given in all surgeries?
No
92
What are the two types of muscle relaxant?
Depolarising and non-depolarising
93
How do depolarising muscle relaxants work?
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
94
Example of depolarising muscle relaxant?
Succinylcholine AKA suxamethonium
95
Suxamethonium dose
1.5-5mg/kg
96
Sux use?
RSI
97
SEs depolarising muscle relaxants
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)
98
How do non-depolarising muscle relaxants work?
Block nicotinic receptors so there is no contraction (competitive with ACh)
99
Example non-depolarising muscle relaxant
Atracurium
100
What is the onset of non-depolarising muscle relaxant?
Slow
101
Suxamethonium is made up of ?
2 Ach molecules together
102
How do you reverse non-depolarising muscle relaxant?
Neostigmine and glycopyrrolate
103
What is neostigmine?
Anti-cholinesterase- prevents the breakdown of ACh
Induces muscarinic effects of ACh e.g. bradycardia, excessive salivation, so you use Glycopyrrolate too.
104
How does glycopyrrolate work? SE?
Antimuscarinic
SE= N&V
105
What is a quicker but more expensive way to reverse non-depolarising muscle relaxant?
Suggamadex
106
Can non-depolarising muscle relaxants trigger malig hyperthermia?
No
107
Do depolarising muscle relaxants need to be reversed?
No, their duration is short and reverse is spontaneous
108
How do you check a muscle relaxant is working in theatre?
Use a nerve stimulant and 'train of 4' technique
109
BP= ? x ? x?
HR x SV x SVR
110
HR x SV =?
CO
111
What are vasopressors used for?
Treat hypotension
112
What is the effect of alpha receptor agonism?
Vasoconstriction
113
What is the effect of beta receptor agonism?
increase HR
114
What is the mechanism (and so the physiological effect) or ephedrine?
alpha and beta agonist
Increases BP and HR
115
What is the mechanism (and so the physiological effect) or phenylephrine?
100% alpha agonist so increases BP but decreases HR (compensatory response to increased BP)
116
What is the mechanism (and so the physiological effect) or metaraminol?
99% alpha, 1% beta agonist so increases BP but decreases HR (compensatory response to increased BP)
117
Reflex bradycardia is more pronounced in which vasopressor?
Phenylephrine
118
In general anaesthetic drugs have what effect on blood vessels?
Vasodilation so decrease SVR
119
What is the mechanism of noradrenaline?
alpha and beta
120
Mechanism adrenaline?
alpha and beta
121
What is the effect of noradrenaline at a low and high dose?
Low- increases SVR
High- increases HR as well
122
As well as noradrenaline and adrenaline, what other vasopressors are used in ICU/severe sepsis?
Dobutamine and glycopyrrolate
123
What inotrope is used in ICU etc?
Atropine
124
What is the action of atropine?
Anticholinergic- blocks parasympathetic NS so HR increased
125
What are the neurotransmitters in the sympathetic and parasymp NSs?
Symp- pre-ganglionic is Ach, post-ganglionic is mainly noradrenaline (adrenergic)
Parasymp- All ACh (cholinergic)
126
What is the incidence of PONV in general anaesthesia
20-30%
127
Ondansetron action?
5HT3 blocker
128
Cyclizine action?
Antihistamine
129
Which steroid can be used as an antiemitic? It is most effective when given when?
dex
when given before anything else
130
Metoclopramide action
Antidopaminergic
131
What is a SE of cyclizine?
Tachycardia
132
What is done in post operative care?
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
What are the steps in induction when an LMA is used?
1. pre oxygenate
2. analgesic
3. induction agent
4. turn on volatile
5. bag valve ventilation
6. LMA insertion
134
What are the steps in induction when intubation is used?
1. pre oxygenate
2. analgesic
3. induction agent
4. muscle relaxant
5. turn on volatile
6. bag valve ventilation
7. intubate
135
Why do you often intubate in abdominal surgery?
Gas pumped into abdo squashes gastric contents- more risk of aspiration so this protects the airway.
136
At which two points can you extubate? Why?
Deeply anaesthetised or fully awake- otherwise laryngospasm
137
What is included in a pre op assessment?
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
What if the pt has GORD?
The muscle relaxant could trigger it and risk aspiration, so RSI
139
Does a pre-op assessment include consent?
No this is done in the surgical one
140
How do you examine the mouth and neck in a pre-op assessment?
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
How many ASA grades are there?
6
142
What is ASA grade 1
Healthy no disease
143
ASA 2
Mild-mod systemic disease w/no functional limitation
144
ASA 3
Severe systemic disease imposing functional limitation
145
ASA 4
Severe systemic disease constant threat to life
146
ASA 5
Not expected to survive without op
147
ASA 6
Brainstem dead pt whose organs are being removed for donor purposes
148
What is the suffix -E in ASA grading?
Emergency surgery
149
How many surgical grades are there?
4
150
What is the name of surgical grades 1-4?
1- minor
2- intermediate
3- major
4- major +
151
Example of minor surgery
Excision of a skin lesion
152
Example of intermediate surgery?
Inguinal hernia
Tonsillectomy
153
Example of major surgery
hysterectomy, thyroidectomy
154
Example of major + surgery?
Joint replacement, radical neck dissection
155
What determines whether surgery is minor/major etc?
How much tissue injury occurs
156
What investigations can be done pre-op? What does it depend on?
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
What are the fasting rules?
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
Half life of water in the stomach?
10-20mins
159
Half life of food in the stomach?
2.5-3h
160
What if emergency surgery is required and the pt has had a meal?
RSI
161
What does pre-oxygenation do?
Replaces FRC with O2
162
What drugs are used in RSI?
Thiopentone (onset 15-30s)
Propofol (onset 30s)
Suxamethonium
163
What extra technique is used in RSI?
Cricothyroid pressure to compress oesophagus until airway secured
164
Is LMA or intubation used in RSI?
Intubation as it protects the airway
165
How do you confirm the position of ETT?
EtCO2 (capnography)
Vapour on equipment
Chest expansion and auscultation
166
USS uses what to create sound waves?
Pizoelectric crystal
167
What tissues reflect ultrasound? How does it appear?
Bone
Hyperechoic (white)
168
What tissues transmit ultrasound? How does it appear?
Vessels
anechoic (black)
169
What tissues absorb ultrasound? How does it appear?
Soft tissue
isoechoic (grey)
170
How do nerves appear on US? why?
Honeycomb- hyper and hypoechoic
171
What tissues scatter ultrasound?
Irregular surface
172
What three things do you need to adjust during USS?
Frequency (select the right probe)
Depth
Gain
173
A ____ frequency probe is used for superficial (<6cm) structures (higher/lower)
Higher
174
When adjusting depth on USS, where should the structure of interest appear on the screen?
3/4 from top
175
What is gain in USS?
Like exposure on a photo
176
On doppler USS, fluid moving towards the probe appears what colour?
Red
177
What does acoustic shadowing artefact mean on USS?
Signal void behind the structure that strongly absorbs or reflects the US wave e.g. bone or stone
178
What does acoustic enhancement artefact suggest on USS?
Increased echoes deep to structures that transmit sound very well e.g. fluid filled.
179
What is a reverberation artefact on USS?
When you see more than one of something eg needle
180
What is a comet tail artefact on USS?
White streaks seen when looking at calcific, crystalline or highly reflective objects
181
What does FAST (scan) stand for
focused assessment with sonography for trauma
182
What does a FAST scan look for?
Free fluid or air in the pelvis, pericardium or abdo
183
What are the four echocardiography views?
Parasternal long axis
Parasternal short axis
Subcostal
Apical four chamber
184
Parasternal long axis view shows which structures?
Both ventricles
LA
Aorta
(coronal view)
185
Parasternal short axis shows which structures?
Both ventricles (axial view)
186
Subcostal view shows what structures?
All four chambers axial view, possibly IVC by liver if turn the probe a bit
187
Apical four chamber view shows which structures?
All four chambers axial view
188
In the WHO surgical safety checklist, at what three points do people stop to check?
Before induction (with at least nurse and anaesthetist)
Before skin incision (plus surgeon)
Before pt leaves theatre
189
How can you monitor temperature during an operation?
Oesophageal temperature probe through nose
190
What are four ways to keep a patient warm in theatre?
Bear hugger
Warmed fluids/gases
Blankets
Ambient room temp
191
What temperature of the patient do you aim for?
>36C
192
How do you reduce VTE and pressure sores?
Gel pads
TED stockings
DON'T routinely give tinz if they will be mobilising soon after
193
Do you use opioids in day surgery?
Try to avoid as it makes them groggy
194
Blood glucose normally _____ during surgery, even in non-diabetics
Rises
195
BM should be taken when in diabetics?
Before, during and after the surgery
196
In major surgery, what changes if they are diabetic?
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
What is sliding scale insulin regime?
Insulin administered separately to dextrose and potassium. The amount of insulin depends on blood glucose- keep adjusting
198
What is the alberti regime?
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
In elective surgery for a diabetic patient what needs to be satisfactory beforehand?
HbA1c
200
How should diabetic patients be managed in minor surgery?
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
What three things might affect the anaesthetic in a diabetic patient?
Increased risk of infection e.g. epidural abscess
Gastroparesis
Stiff neck/jaw due to glycosylation in TMJ or cervical spine
202
If they are bradycardic and hypotensive during surgery what can you give?
noradrenaline (alpha and beta)
or ephedrine (alpha, beta1 and beta2 agonist, direct and indirect- releases noradrenaline- actions. IV.)
203
What is the problem with ephedrine?
Tachyphylaxis- gets less effective the more it is given.
204
If a patient is hypotensive only during surgery what can you give?
Metaraminol (99% alpha)
205
What is the equation for oxygen delivery?
Cardiac output x conc. Hb x SpO2 x 1.34
206
How does water enter cells?
Via sodium potassium channel
207
How is water distributed within the body?
Total 42L
2/3 (28L) intracellular
1/3 (14L) extracellular- 25% intravascular (3.5L) and 75% interstitial (10.5L)
208
Which fluid is most similar to water?
Dextrose- the sugar is metabolised so what is left is the same as water (same distribution) so 1L = about 100ml intravascular
209
what happens if too much dextrose is given?
hyperglycaemia and dilutional hyponatraemia
210
Which fluids are most similar to extracellular fluid? (go extravascular but not into cells})
Crystalloids
1L = 250ml intravascular
211
What can too much sodium chloride fluid cause?
hyperchloraemic alkalosis
212
What does Hartmann's contain as well as sodium and chlorine?
lactate
Potassium
Calcium
213
What is starling curve?
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
How can imaging help determine fluid status?
Oesophageal doppler- see stroke vol and cardiac output
215
Two invasive ways to measure fluid status?
Art line
CVP (central venous pressure)- measures RV end diastolic pressure- assume equivalent to LV EDP and therefore volume
216
Prescribing fluids should account for which two things
Maintenance
Perioperative loss
217
L water required per day for maintenance?
2.5L
218
How much Na2+ required per day for maintenance?
50-100mmol/1-2mmol/kg
219
How much K+ required per day for maintenance?
40-80mmol/1mmol/kg
220
If the gut is working how should you give fluids?
Oral
221
If there are extra fluid losses, how do you know what to replace it with?
In general like with like, work out the volume and electrolytes lost
222
How much sodium and Cl in NaCl 0.9%?
154mmol each per L
223
How much sodium, Cl and K+ in Hartmann's
131mmol Na2+
11mmol Cl-
5mmol K+
224
What is a fluid challenge
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
What is a reversible way to test if they need a fluid challenge?
Passive leg raise to 45 degrees for 1min
Really need an art line to see the change in stroke vol
226
A well 60kg woman NBM, needs maintenance for 24hrs, currently hydrated and no abnormal losses. What should you give?
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
How do you extubate?
Wait until breathing themself and then do it in theatre
228
How do you remove LMA?
Disconnect when breathing, take to recovery, handover
229
What are the levels of care?
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
What are the stages of recovery?
Stage 1- airway in
Stage 2- airway out then ward if 0. Spend about 20min in theatre recovery
231
Drugs to treat shivering/tremors in post op?
Pethidine, ondansetron, anticholinesterases (e.g. propofol)
232
Are fluids necessary post op?
Not if they can drink normally
233
Does fluid provide calories?
No so if prolonged NBM give parenteral feed
234
True or false oxygen always required after sedation?
Yes as hypoxaemic- venturi or simple face mask or nasal prongs
235
What % get PONV?
about 30%
236
What can help avoid PONV?
Avoid use of NO2
Total IV anaesthesia
237
What drugs should be given post op
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
What are the four categories of CEPOD classification
Immediate
Urgent
Expedited
Elective
239
What is CEPOD immediate?
life/limb/organ saving
resus and surgery simultaneous
Surgery within minutes
e.g. aneurysm rupture
240
What is CEPOD urgent?
life/limb/organ threatening
Surgery w/in hours
e.g. bowel perf
241
What is CEPOD expedited?
Within a day or two
e.g. large bowel obs, closed long bone fracture
242
What is CEPOD elective?
Timing to suit hospital and patient e.g. joint replacement, cataract
243
Treatment for aspiration during anaesthetic?
100% O2
Suction
Tracheal intubation and suction
Post op physio and O2
244
Patient under anaesthetic has:
Increased HR
Decreased BP and SpO2
Acute decrease EnCO2
Millwheel murmur
Air embolism
245
What procedures can cause air embolism?
Air in IV
C section
Central line
Use of high pressure gas e.g. laparoscopy
246
Treatment air embolism
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
Where does the air embolus go?
RA and RV
248
Why does malignant hyperthermia occur (at a molecular level)
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
When should you stop taking COCP before (elective) anaesthetic?
4w- VTE risk
250
Why does laryngospasm occur
Airway irritation e.g. ETT when not deeply anaesthetised enough
251
Signs laryngospasm
Airway obstruction
Paradoxical breathing in spontaneously breathing pt
252
Rx laryngospasm
positive pressure with high flow o2
Deepen anaesthesia
Sux
253
How should failed intubation proceed? stepwise
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
What about a 'can't intubate can't ventilate' situation
Needle or surgical cricothyroidotomy
255
What triggers malignant hyperthermia?
Volatiles
Sux
256
What is the pathophys of malig hyperthermia
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
Inheritance of malignant hyperthermia gene
Autosomal dominant
258
Rx malig hypertherm
Remove trigger
100% O2
Cooling
Dantrolene IV (1mg/kg up to 10) inhibits Ca2+ release in muscle
to ICU
259
How can you test for malig hypertherm
Muscle biopsy
260
Why does suxamethonium apnoea happen?
Genetic, lack enzyme to metabolise sux so it lasts longer
261
Sux apnoea could potentially cause what
awareness
262
Rx sux apnoea
Maintain sedation and ventilate them on ICU until it wears off
263
sux apnoea is also linked to failure to metabolise which non-depolarising muscle relaxant?
Mivacurium
264
Signs of anaphylaxis during anaesthetic?
Rash
Wheeze
Increased ventilatory pressure
Drop in BP that is unresponsive to Rx
Angioedema
Tachy/bradycardia
Dysrhythmias
265
Rx anaphylaxis during anaesthetic
Remove stimulus
ABC, 100%O2
ETT
Adrenaline
Fluid
Chlorpheniramine (antihist) 10mg
Hydrocortisone
Salbutamol
266
SVT Rx in anaesthetic
Valsalva manoeuvre
Ice cold stimulus to neck
Carotid massage
Drugs
