Anaesthetics Flashcards
(167 cards)
1
Q
Basic techniques to stabilise an airway (2)
A
Head tilt chin lift
Jaw thrust
2
Q
% of O2 in 15L via NRBM/Reservoir mask
A
85%
3
Q
Indication for an airway adjunct
A
Airway patent on manoeuvre but stops when not
4
Q
How do you measure the size of Oropharyngeal airway needed
A
Angle of mandible to incisors
5
Q
CI for Oropharyngeal airway
A
Conscious
Gag reflex
6
Q
Indication for Nasopharyngeal airway
A
Cannot tolerate OPA because they are conscious
7
Q
CI for NPA
A
Basal skull fracture (Panda eyes and Battle’s sign)
8
Q
How do you measure the length of the NPA an individual requires
A
Tragus to incisor
9
Q
Size of NPA for males and females?
A
M= 7
F=6
10
Q
Nasal cannulae oxygen delivery?
A
1-6L/Min
Max 40% O2
11
Q
Hudson mask/simple face mask oxygen delivery?
A
5-10L
12
Q
Venturi mask advantage?
A
Controlled amount of 02 delivery
13
Q
O2 delivery from a venturi mask in increasing order
A
Blue= V24= 2-4L/min White= V28= 4-6L/min Yellow= V35= 8-10L/Min Red= V40= 10-12L/Min Green=V60= 12-15L/Min
(Vx= % O2 delivered)
14
Q
When using the bag-valve mask how many breaths per min and how hard do you squeeze it?
A
12/min
1/3rd volume of the bag
15
Q
Requirements for NIV?
A
Alert Conscious Co-operative Cough Can maintain own airway Own resp effort is good
16
Q
Indication for CPAP
A
Acute hypoxic respiratory failure
17
Q
Indications for BIPAP
A
Hypercapnic COPD exacerbation
18
Q
Size of LMA in males and females
A
Male= 4 Female= 3
19
Q
If not anaesthetist is present what airway is 1st line in a cardiac arrest
A
LMA
ET tube them if anaesthetist is present
20
Q
ET tube size in Males and Females
A
M= 9 +/- 0.5 F= 8 +/- 0.5
21
Q
Where do the two black lines go when the ET tube is inserted
A
On either side of the vocal cords
22
Q
How do you hold a laryngoscope and where does it go?
A
Left hand
Valecular
(use chin lift)
23
Q
How do you confirm the position of an ET tube?
A
Capnograph- CO2 in expiration Auscultate over lungs- Apices and bases +/- Stomach Direct visualisation Misting in tube Symmetrical chest movement \+/- Sats rising
24
Q
Early and late complications of an ET tube
A
Early- Trauma, aspiration, airway obstruction, hypoxia if prolonged attempts
Late- Infection, mucosal damage, vocal cord injury
Tracheal stenosis
25
Indications for a tracheostomy
```
Emergency access
Upper airway obstruction
Impaired resp function E.G Head trauma
Assist in ventilation weaning
Long term ventilation
```
26
Indications for a cricothyroidotomy
Emergency airway
| Obstruction at or above larynx
27
Process of anaesthesia (6 steps)
Pre-op assessment
IV access/Monitoring (14G-24G)
Induction
Analgesia + muscle relaxation
Maintain AMNESIA, AKINESIS AND ANALGESIA
Reversal
28
How is amnesia achieved
Induction agent lasting 4-10 mins
Maintained via inhalation/volatile agents
29
Advantages and disadvantages to Propofol
+ Suppresses airway reflexes
+ Decreased PONV
- Involuntary movements
- Marked reduction in HR & BP
- Pain upon injection
30
What is propafol
Induction agent to induce amnesia
lipid based therefore white emulsion
1.5-2.5 mg/kg
31
What is thiopentone
Barbituate used to induce amnesia
4-5mg/kg
Used for RSI
32
Advantages and disadvantages to thiopentone
+ RSI (FAST ONSET)
+ Anti-epileptic so protects the brain
- BP decrease with HR increase
- Rash
- Bronchospasm
- CI in porphyria
- Thrombosis and gangrene if intra-arterial as blocks arterioles
33
When is Ketamine used as an induction agent
What form of amnesia does it cause?
Good as sole anaesthetic for short procedures E.G burn dressing change
1-1.5 mg/kg
Dissociative= Profound analgesia and anterograde amnesia
34
Advantages and disadvantages to Ketamine
+ Slow onset (90s)
+ Increase in HR & BP
+ Bronchodilatation
- N&V
- Emergence phenomenon- vivid dreams and hallucinations
35
What is Etomidate
Steroid based induction agent
Rapid onset
Use if you want to minimise haemodynamic instability
36
Advantages and disadvantages to etomidate
+Haemodynamic stability
+ No impact on BP
+ Lowest hypersensitivity risk
- Pain upon injection
- High incidence of PONV
- Spontaneous movements
- Adreno-cortico suppression
37
What 2 methods are used to maintain amnesia?
Total IV anaesthesia- Propofol infusion via IV + Fentanyl
Inhalation anaesthesia using an inhalation agent
38
Inhalation agents- Benefits of Isoflurane
Lowest impact on organ blood flow
| Good if an organ donor!
39
Inhalation agents- Benefits of Sevoflurane
Sweet smelling
Good for children
Inhalation induction
40
Inhalation agents- Benefits of Desflurane
Rapid onset and offset- Does not accumulate in fat!
| Good for long operations
41
What is the minimum alveolar concentration
Concentration of vapour that prevents reaction to a set depth and width of skin incision in 50% of patients
BUT provides amnesia in 100%
42
```
MAC of:
Nitrous oxide
Sevoflurane
Isoflurane
Desflurane
Enflurane
```
```
Nitrous oxide- 104%
Sevoflurane- 2%
Isoflurane- 1.15%
Desflurane- 6%
Enflurane- 1.6%
```
43
When are short acting analgesics used?
| Give examples of them.
Intra-operatively, suppress response to layrngoscope, surgical pain
Remifentanil, Alfentanil, Fentanyl
44
Of Remifentanil, Alfentanil and Fentanyl which is most potent with the fastest onset?
Which can be given IV?
Remifentanil> Alfentanil>Fentanyl
Remifentanil- IV
45
Which NSAIDS can be given IV
Parecoxib
| Ketorolac
46
In a surgical setting when should morphine/Oxycodone be given?
Intra- or Post-operatively
If the former then give 15-20 mins before the end of the operation
47
Give examples of short,Int and long acting non-depolarising muscle relaxants
Short- Atracurium, Mivacurium (30 mins)
Int- Rocuronium, Vecuronium (30-60 mins)
Long- Pancuronium (60+ mins)
48
Mechanism of action and Properties of non-depolarising muscle relaxants
Blocks Nicotinic R preventing depolarisation by Ach
Slow onset, variable duration, fewer side effects
49
Mechanism of action of depolarising muscle relaxants
Mimic Ach so bind nicotinic receptors inducing a contraction/fasiculations (PHASE 1)
Desensitisation to the efffcts of Ach with muscle fatigue and relaxation
50
What is Suxamethonium
A non-depolarising muscle relaxant
1-1.5 kg/mg
Quick onset and offset (use in RSI)
51
Suxamethonium Side effects?
Fasiculations, Pain, HYPERkalaemia, Prolonged apnoea
Inc ICP/IOP/Gastric pressure
Malignant hyperthermia
52
How do you reverse suxamethonium related malignant hyperthermia
Dantrolene
53
What reversal agent potentiates the action of Suxamethonium
Neostigmine
54
What is neostigmine?
| What must it be given with?
Anti-cholinesterase so prevents Ach breakdown to can reverse the action of non-depolarising muscle relaxants
Add an anti-muscarinic like glycopyrolate to prevent bradycardia
55
Drawbacks of neostigmine
N&V, cannot reverse profound block, slow onset and peak at 7-11 mins
56
What is sugammadex?
Causes water soluble complex formation to immediately reverse the effects of a muscle relaxant
Nil effect on nicotinic receptors
16 mg/kg if wanting immediate reversal
57
Drawbacks of sugammadex
Hypotension
Airway compromise if lower dose
VERY EXPENSIVE SO ONLY USE WHEN NECESSARY
58
What is Ephedrine
Inotropic agent acting on alpha and beta receptors
| Increases both HR and BP
59
What is phenylephrine?
Inotropic agent acting directly on alpha receptors
Increase in BP (B/C VASOCONSTRICTION)
Decrease in HR
60
What is metaraminol?
Inotropic agent mixed direct/indirect action mostly on alpha receptors
Increase in BP (B/C vasoconstriction)
Decrease in HR
61
Inotropic agents used in ICU/Sepsis
NorA, Adrn, Dobutamine
62
What % of GA patients will vomit?
20-30% without medication
63
When would you give sodium citrate/H2 antagonist (antacid)
Aspiration risk E.G in Obstetrics/Obese/GORD/Difficult airway
64
Process of anaesthetic reversal
Stop vapours
Give O2
Throat suction
Reverse muscle relaxation
65
What are the two types of LA?
Esters- lipid soluble hydrophobic aromatic group (Procaine, Benzocaine, amethocaine, cocaine)
Amides- Charged hydrophilic group (Ropivacaine, Prilocaine, Levobupivacaine) REMEMBER BY HAVING 2 'i' in their name
66
Max dose of Lignocaine
3
7 with adrenaline
67
Max dose of Bupivacaine/Levobupivacaine
2 (no change with adrenaline)
68
Max dose of Prilocaine
6
9 with adrenaline
69
When should you not use adrenaline
On terminal regions like the penis or digits
70
What is LA toxicity? Describe the presentation.
Exceeding max safe dose leading to Na+ channel blockage in the brain and heart
```
Confusion/Drowsiness/Coma/Convulsions/Light headedness/slurring of speech
Tingling around mouth
Excitatory symptoms
Muscle twitching
CV toxicity
```
71
How does LA toxicity impact the CV system?
Initial Tchycardia + HTN
Later hypotension and bradycardia
Leading to heart block and ventricular arrhythmias
72
Treatment of LA assoicated cardiac arrest
Intralipid 1.5 mls/kg
Keep doing CPR for 1 hour as intralipid takes a while to work
Iv Benzo if convulsing
Atropine if bradycardia persists + raise legs to treat hypotension
73
Steps to working out safe dose of LA
Work out max dose of drug in mg by multiplying max dose (mg/kg) by weight (kg)
Convert % of drug into mg/ml by multiplying by 10 (0.25%= 2.5mg/ml)
Divide Max dose (mg) by aforementioned how much mg/ml can be used (mg/ml)
Final figure in Ml
74
Where does the SC end?
Lower border of L1
75
Where does the SA space end?
S1
76
Where does the epidural space end?
Sacrococcygeal hiatus
77
Where does a spinal block inject into
Subarachnoid space
78
Where does an epidural inject into
Epidural space
79
Where can you do a spinal block?
L2 to S2
The lower the safer!
Harder past L5
80
Where can you do an epidural block?
Any level;
| Risk SC damage if above L1
81
Benefits of Spinal/epidural over opiate analgesia
```
Fewer post-op respiratory complications
Less PONV
No precipitation of obstructive sleep apnoea
Less chance of infection
Decreased CV/Resp impact
```
82
How do you test for spinal onset?
Cold spray
| Ice cube
83
Describe a spinal block
5-10 min onset Lasts 2-3 hours
RAPID ACTION
Dense motor block
84
Describe an epidural
LA +/- Opioid
10-15 min onset (Slower than spinal)
lasts up to 72 hours
Catheter can provide continuous infusion
85
CI for spinal/epidural
Increased ICP (coning risk)
Aortic/Mitral stenosis
Sepsis
Coagulopathy
86
Ways in which pain can be classified
Duration
Cause
Mechanism- Nociceptive vs neuropathic
Perception
87
What is nociceptive pain
Obvious tissue injury
Well localised
Dull if visceral
Sharp if muscles/bones/skin
88
What is neuropathic pain
Nervous system damage/abnormality
No protective function
Poorly localised
Neuro symptoms
89
Are alpha delta or C nerves faster?
Alpha delta- Faster sharp pain
| C nerves- Persistent pain (Burning)
90
How do you treat acute nociceptive pain
Reverse WHO ladder
Trauma or Post-op!
Step down as pain improves
91
Key pain Q
How long
Cause
Pain mechanism
92
What is clonidine?
Alpha agonist.
Works centrally to ameliorate pain
Decreases BP
Sedative effect
93
Minimum recommended fasting time for:
Solids
Milk
breast fed infants
Solids- 6 hours
Milk- 6 hours
breast fed infants- 4 hours
94
Minimum recommended fasting time for:
Clear fluids
Alcohol
Boiled sweets/chewing gum
Clear fluids- 2 hours
Alcohol- At least 24 hours
Boiled sweets/chewing gum- Avoid but carry on with surgery
95
What is the lowest ml of fluid associated with morbidity in surgery
30ml
96
Impact of prolonged fasting
Headache, Anxiety, N&V, Dehydration, Hypotension, Metabolic disturbance
97
Factors impacting gastric emptying
Diabetes, CKD, Pyloric stenosis, Pregnancy, Obesity, Head trauma
98
Up to what time are children allowed H20 before surgery
1 hour before
99
Rapid sequence induction- indication
Full stomach
| Use cuffed ET tube
100
RSI 3 phases
1) Preoxygenation with 3 mins tight fitting face mask or 5 full VC breaths
2) Induction with thiopentone or propofol + Recuronium or suxamethonium
3) Cricothyroid pressure + no ventilation (gentle if desaturate) + remove once ET tube in
101
Side effects of GA
Sore throat, tissue damage, confusion memory loss
Infection is uncommon as is teeth damage.
Eye damage is rare
102
Phases to pre-op assessment
```
Introduction/Details
Previous anaesthetic Hx
Exercise tolerance
General health
CVS/Resp/GI- Inc DM/Neuro/MSK/Dental
DHx
SHx
FHx- Problems with anaesthetic
Fasting check- clear fluids oly 6 hrs before then NBM 2 hours before
Examination and Mallampati score
```
103
ASA grading
```
1- Healthy
2- Mild-mod sys disease with no limitation
3- Severe sys disease with limitation
4- Constant threat to life
5- Not expected to survive
```
104
Pre-op investigations if:
>80
60-80
<60
>80- FBC, U&Es, ECG
60-80- SG>3 get all above, FBC only if SG2
<60- SG>3 get FBC (+U&Es if SG>4)
105
Surgical grades 1-4
1- Minor (Skin excision)
2- Intermediate (Tonsillectomy)
3- Major (Hysterectomy)
4- Major + (Joint replacement, thoracic)
106
RF for post-op N&V
Young. Female. Anxious. Etomidate. No2. Opiates. Volatile agents. Abd surgery
107
Treating intra-operative N&V
Ondansetron or Dex
108
Treating recovery N&V
Ondansetron is generally considered to be 1st line
| Dexamethasone, cylizine, prochlorperazine are all alternatives
109
Post op fluid aims
Replace loss and achieve optimum SV/CO
110
What factors impact the speed of LA
Baricity, conc, volume, level of injection, speed of injection
111
```
CEPOD examples for
Immediate
Urgent
Scheduled
Elective
```
Immediate- life/organ saving, resus, AAA, fasciotomy
Urgent- 6 hours- Potentially life threatening, hours available for resus
Scheduled- 24-58 hours- Not an immediate threat to life (Tumour excision that if left could bleed)
Elective- Planned to suit patient
112
Order of process for GA + Intubation
```
Oxygenation
Opioid
Induction
Volatile agent
Bag-mask
Muscle relaxant
ET intubation
```
113
Order of process for GA + LMA
```
Oxygenation
Opioid
Induction
Volatile agent
Bag-mask
LMA insertion
```
114
What is high frequency USS?
7-18Hz
Poor depth
Linear probe
SUPERFICIAL STRUCTURES
115
What is low frequency USS?
2-6Hz
Curvilinear probe
DEEP STRUCTURES
116
What primarily generates resolution on an USS?
Frequency
117
How and why do you adjust depth on an USS?
Want subject in the centre
| so start with high depth and then adjust
118
How and why do you adjust gain on an USS?
Artificial multiplication of a structure
| Better able to see deeper structures
119
Blood moving away is generally what colour on a doppler USS?
Blue
120
Blood moving towards is generally what colour on a doppler USS?
Red
121
What is a FAST scan?
Focussed Assessment Sonography for Trauma
Detects fluid/bleeding
Low specificity to cannot rule in
Misses retroperitoneal bleeds
122
Mallampati scores
1->4
What score signifies a difficult intubation?
1- See everything
2- See whole uvula (cannot see ant/post pillars completely)
3- Only uvula base
4- Soft palate not visible
3&4= Difficult intubation
123
What are your goals for treating shock?
```
Normalise lactate
UO>0.5
MAP>65
Central venous oxygen sats >70%
CVP 8-12 mmHg
```
124
Examples of vasopressors
Noradrenaline, Phenylephrine, Vasopressin, Metarminor
125
Examples of inotropes
Adrenaline, Dobutamine, Isoprenaline, Ephridine
126
When would you use Noradrenaline in shock?
Low CO
| Septic shock
127
In what type of shock are vasopressors like NA, Vasopressin, phenylephrine indicated
Distributive
128
In what type of shock are inotropic agents like dobutamine indicated
Cardiogenic
129
What does CVP inform you of?
Fluid status, look at trend post-fluid
130
Key signs of shock
What compensatory signs may be seen
Hypotension (NOT ESSENTIAL...)
High lactate (>3)
BE
131
A bounding pulse can be a sign of what type of shock
Distributive
132
What is Beck's triad?
Tamponade
Hypotension, Inc JVP, Pul oedema, Faint heart sounds
133
Describe obstructive shock
```
Afterload problem (Outflow block)
PE, Tamponade, Pneumothorax, Fluid overload
```
134
Poor prognostic signs in hypovolaemic shock
```
BP<90
Low GCS
Mottled
Unresponsive to fluid
Ongoing bleed
```
135
What are the 4 types of shock
Hypovolaemic
Cardiogenic
Obstructive
Distributive
136
Levels of care 0-3
0- Normal ward
1- Inc deterioration risk (CC Outreach)
2- Single failing organ system/Major burns
3- ICU (MULTI-ORGAN FAILURE)
137
If a patient comes to ICU their clinical state must be...
Potentially reversible
| Long term health means patient can benefit from intensive care
138
How do you assess volume status
```
UO
HR
inc albumin inc urea (if dehydrated)
Haematocrit (inc if dehydrated)
creatinine
Skin turgor
BP
```
139
What is the 4, 2, 1 rule for fluid maintenance?
4ml/kg/hr for 1st 10kg Wx
2ml/kg/hr for next 10kg
1,l/kg/hr for remaining ideal Wx
Most adults 20-30ml/kg/hr
140
On an echo what does the IVC size suggest about the type of shock?
Small IVC- Hypovolaemia
Dilated IVC- Decreased contractility, so likley cardiogenic
Loss of normal structure= Tamponade? Obstructive shock
141
Parasternal echo veiw shows...
Transverese of long axis view
142
Apical echo view shows...
4 chambers
143
Subcostal echo view shows...
IVC- N.B. Should collapse <50% on insp)
| Can also have a 4 chamber view
144
What is T1RF?
Hypoxaemia because V/Q Mismatch
Pneumonia, asthma, COPD, pneumothorax, ARDS, CHD, Bronchiectasis, Pul. HTN
145
What is T2RF?
Hypoxaemia and Hypercapnia due to ventilatory failure
```
Neuromuscular- Flail chest
COPD/ASTHMA when severe and tired
Oedema
Loss of Resp drive
Hypoventilation
Trauma
```
146
What is the pathophysiology of ARDS?
Lung damage secondary to severe systemic illness
Induces a rise in inflammatory mediators
Increases cap permeability, Non-cardiogenic pul.oedema, Multi organ failure
147
What is Fi02?
Fraction of inspired oxygen
| Helps to contextualise hypoxia
148
What is the main indicator for oxygen?
Hypoxaemia NOT BREATHLESSNESS
149
What does CPAP do to the airways?
Splints them open to improve FRC
| Net effect to ameliorate V/Q mismatch
150
Type of respiratory failure where CPAP is used?
T1RF
151
How does BIPAP work?
CPAP + additional pressure to support ventilation
| Increasing TV
152
Type of respiratory failure where BIPAP is used?
Hypercapnic COPD exacerbations
MSK conditions where there is respiratory failure
HELPS VENTILATION
153
Problems with ET tubes and sedation
Hypotension
Gastroparesis
Immobility
Pneumonia risk
154
Signs of increased ICP
Pupillary dilatation
Sluggish then fixed pupillary reflexes
Aphasia
Reduced consciousness/GCS
155
How do you manage increased ICP in ICU?
```
Avoid pyrexia
Prevent seizures
Elevate head to 30 degrees
Sedation
Ameliorate hypoxia and hypercapnia
Hypertonic saline
Mannitol (Inc blood osmolarity)
Decompressive craniotomy
```
156
What is a poor prognostic sign on CT after brain injury?
Loss of differentiation
| Looks hazy grey
157
Secondary brain injury precipitated by...
Hypoxia
Hypoperfusion
Hypoglycaemia
158
What does renal failure indicate about end organ perfusion in a critical care context?
Poor end organ perfusion
| Look for anuria and increased serum creatinine
159
Complications of renal failure?
Uraemia- Encephalopathy, Pericarditis, Coagulopathy
Fluid overload
Metabolic acidosis
Hyperkalaemia
160
5 major principles of the MCA?
```
Presumption of capacity
Support to make own decisions
Able to make an unwise decision
Best interests checklist if no capacity
Least restrictive option that infringes on freedom least
```
161
Principles of capacity
Understand, Retain, Weigh up, Communicate
162
What is futility?
Low treatment efficacy
| Physiological (Quantitative/Qualitative) or cost-based
163
What is death?
Irreversible loss of capacity for breathing and consciousness
164
How do you confirm brainstem death?
Continuous loss of Cardio-resp function for 5 minutes
Pupils, Supra-orbital pressure, corneal reflex
May still have beating heart...
165
Deceased donors must be Dx by how many consultants?
| The death must be what?
3
Also must be on ventilator
Predictable and controlled death!
166
Process of organ donation in brainstem death
Test to confirm death > optimise physiology > Mobilise team > Organ retrieval
TAKEN TO THEATRE ONCE RETRIEVAL TEAM HAS ARRIVED
167
Process of organ donation in circulatory death
Mobilise team > Stop support> Death within time constraint> Dx death > Organ retrieval
Potential for stand down therefore not definitely going to theatre like in brainstem death, plus team is mobilised earlier
