OSCE 1 Flashcards
1.1 a Check the breathing system on machine circle absorber
- Visual inspection
- Ensure soda lime present not used up
- Identify blockages
- Leak test
- Flow 0, Close APL, Occlude Y, pressure bag to 30cmh20 w/ flush, ensure remains fixed >10s, open apl - ensure decreased - Leaks?
- 1 way valves - connecting bags
second bag - sim lung on Y, fill with flush + manually ventilate - ensure inflate and deflation lung connected y - watch movement unidrectional
1.1 b What are the benefits of the system circle absorber
- Economy - FGF reduced - <1lmin, reduced consumption volatiles
- Humidification - inspired gas saturated w/ water vapour from expire gas
- Reduce heat loss - conservation of heat - exothermic reaction co2 absorption assists maint body temp
- Reduced pollution - using low FGF - escaped volatile minimised
1.1 c What happens if a unidirectional valve malfunctions
Mixing of inspired gas with expired gas - Co2 = hypercapnia
1.1 d What is the mesh size of granules
what’s that in mm
What do you understand by x-y mesh
4-8 mesh or 3-4 mm spheres
Strainers w/ 4-8 mesh - 4 equal strands per linear inch both vertical + horizontal axes
8 mesh = 8 = strands per linear inch
granules of 4-8 mesh size pass thru strainers w/ 4-8 mesh
1.1 e What constitutes soda lime
What are contaminants produced w/ soda ime
NaOH, CaOH, KOH, Water, Silica
Compound A - sevo
CO - des iso enflurane
methane + acetone also produced
1.1 f Chemical reactions soda lime
Co2 reacts w/ water = carbonic acid - reacts cal hydrox - calc carb and water
co2 also reacts w/ naoh -> sodium bic - reacts calcium hydroxide to regenerate sodium hydroxide
CO2 + H20 -> H2C03 & H+ & HCO3-
CaOH2 & ++ & HCO3- -> CaCO3 + 2 H2O
CO2 + 2 NaOH -> Na2CO3 & H2O & Heat
Na2CO3 & CaOH2 -> 2NaOH & CaCO3
water required for absorption
moisture already present
more added patient
1.1 g Unidirectional valve - how does it function
Inspiration -
FG & CO2 free gas from reservoir bag passes thru inspiratory unidirectional vavle & inspiratory limb to patient
During expiration
inspiratory undirect valve closed and expire gas from exp limb pass thru expiratory unidirectional valve to soda lime canister
1.2 ECG
Trop T - greatest sensitivity and specificity detecting Acute Mi
norally not serum
Aspirin decrease mortaility
Delta wave - WPW
1.3 Haemodynamics
Cardiac index calculation
Normal ranges
SVR calc
normal range
SVRI
DO2
CaO2
PVR
CI = CO / BSA
2.8-3.5
Stroke index = SV/BSA
SVR = MAP - CVP / CO x 80
900-1200
SVRI = SVR/CI -
Fluid guidance - BP, CVP, Wedge
DO2 = CaO2 x 10 x CO
CaO2 Hb x SaO2 x 1.34/100
1
PVR PAP - PAWP / CP x 80
1.4 Stats
Correlation coefficient is denoted by
what is it
Regression involve
R ranges from
Independent variable
Independent variable plot on
complete absence
Correlation coefficient is denoted by letter R
denotes association between 2 quant variables
Regression involves estimating best straight line to summarise association
R ranges from 1 -> -1
When 1 vary increase w/ other - positive
Independent variable plot on X axis
Assoc strength
0.2 very weak .4 weak .6 mod .8 strong 1 strong
complete absence represented by 0
correlation =/= causation
Significance of data tested using t-test for parametric data or a non paratmetic test - spearman rank correlation
1.5 Anatomy IJV
label pg 19
Describe course
Tributaries
Originates @ jugular foramen -continues w. sigmoid sinus runs down neck terminate between sternoclavicular joint join subclavian vein form brachiocephalic
Common facial Vein
Lingual Vein
Superior and middle thyroid veins
Pharyngeal venous plexus
1.5 Anatomy IJV
Relations
ant x3
post x 3
med x3
Anterior
1 ICA
2 Vagus between V+A
3 SCM lower part b
Posterior
1 Symp Chain
2 Dome pleura
3 Thoracic duct
medial
1 Carotid Artery
2 CN IX-XII
3 Deep cervical LN close to vein
1.5 b Describe CVC insertion
1 Sterile + head down
2 LA to skin
3 US + use
4 approiate skin punc + direction needle
5 aspiration blood + insert guidewire
6 Passes dilo and railroad cvc catheter
7 Aspirates lumens + suture
8 CXR
1.5 c CVC complications
group
A Mechanical
Needling / Introduction catheter
1 Haemorrhage 2 PTX 3 Haemothroax 4 Air embolism 5 Nerve damge 6 exvasc catheter placement 7 chylothorax
B Infective
C Thrombotic
1.5 d Veins of head and neck on page 19
1 Supficial temporal vein 2 facial vein 3 retromandibular v 4 IJV 5 Ant jug v 6 post auricular V 7 EJV 8 Vertebral
1.5 e
Tributaries of IJV
1 Inferior petrosal vein 2 Pharyngeal veins 3 Facial vein 4 Superior thyroid vein 5 Middle thyroid vein 6 EJV 7 IJV 8 Ant jug v 9 Brachiocephalic V 10 Subclavian V
1.6 F
Major veins of head and neck describe
Ijv contin of sigmoid sinus
Runs down neck vertrical
lateral to interal carotid artery
then lateral to CCA
Glossopharyngeal + hypogloassal N
-forward between IJ and CCA
Vagus descend between and behind v + a in same sehath
Many tributaries within neck
Inferior petrosal sinus, common facial, lungual pharygneal super midldle thyroid veins
sometimes occip
EJV commences sub of partoid gland @ level mandilbe
passes down to midpoint of clav and enter subclav vein
crosses SCM
RIJ is straighter - more common for canullation
NICE - US
1.7 ATI
a
Awake tracheal intubation explain to pt
14 points on marking sheet
1 Introduce
2 Understanding previous problem
3 Explain why intubate
4 Normally done
5 Why different
6 Other methods - VL after induction
7 Disadvantage
failure intubvate
further danger d/t difficulty BMV
8 Adv / benef
Maint airway = safer
9 May use sedation
10 monitoring
11 LA tech
12 Compare to camera test
13 simple terms
14 clarity
1.7 ATI b indication C/I Procedure
how
why nose
Indi - known / suspected difficult airway
aspiration risk + difficult intubate antic
cervical cord instabiltiy
c/i rel upper airway bleeding bleeding tendency stridor uncoop patient
full monit
iv acces
supplement o2 thr
sedation + reversal
head end / operator in front
Nasal - Alignment / uncomfortable
1.7 ATI
C
Techniques airway anaesthesia
Nose
Oropharynx
Lower airway
1 Nose
Cocaine 1.5mg kg or
lidocaine 5% w/ phenyl 0.5%
Oropharynx Lido 4%
gargle 4-5ml solution
3-4 spray of 10% lidocaine (spray 10mg)
Neb also a technique
Lower airway
Spray as you go
4% lido - thru scope w/ epidural catheter down scope
direct visualisation
scope adv to base 2ml 4% sprayed
another 1-2,ml sprayed glottis and vocal cord
scope advance & 1ml thru vocal cords
Total 3-6ml 4% required
1.7 ATI
Internal laryngeal N
Int laryngeal nerve
branch superior laryngeal
block internal / external approach
hyoid bone located directly above thyroid
greater horn - located lateral most part none
SLN block walking 25g needle off greater horn inject 2ml 2%
accident art inject into CCA possible complication
internal laryngeal run under muc membrane covering piriform fossa
Trans laryngeal skin cricothyroid infiltrate w/ LA needle / cannula attach to syringe - n saline thru cric direct bac and caudal avoid vc trauma aspiration air 4ml 4% lido inject end inspiration cough - spread above below
1.7 Surgical cricothyroidotomy ? NOT RECOMMENDED PRACTICE NO MORE? - LOOK UP
FONA das algorithim
1.7
b
Cricothyroid membrane
subcutaenous midline structure
between strap muscles of neck
8mm deep below skin
rang 3-14mm
adults 9mm high 22-30mm wide
wargest tube <9mm outer diam
Identify
feel thyroid notch & follow down
identify stabilise catilage thumb and middle using index locate membrane in midline
not pro pal trachea and follow up
1.8 Trauma patient assessment
A B C D Rapid prim survey resus vital fxnions detailed assessment and initiation dfinitice care
1.8
b
Indication for CTB in head injury x7
RFactors to warrant further look x 3
1 GCS < 13 on initial assessment ·
2 GCS < 15 at 2 hours after injury on assessment in
the emergency department ·
3 Suspected open or depressed skull fracture ·
4 Any sign of basal skull fracture ·
5 Post-traumatic seizure ·
6 Focal neurological deficit ·
7 More than one episode of vomiting since the head
injury
risk factors
1. Age > 65 years ·
2. A history of bleeding or clotting disorder · Dangerous mechanism of injury (a pedestrian
or cyclist struck by a motor vehicle, an
occupant ejected from a motor vehicle or a fall
from height of > than 1 metre or 5 stairs) ·
3.More than 30 minutes’ retrograde amnesia of
events immediately before the head injury
On assessment can the patient actively rotate the neck to 45 degrees to the left and right? if Y - no need for further
1.8 c
Neurosurgical r/f
- Persisting coma GCS 8< after initial resus
- Confusion >h
3 Deterioration in LOC after admin
4 Progressive FND
1.9 PA Catheter
dNormal PCWP
where does prox lumen open
where from tip
how much volume in baloon
draw traces
wheres the thermistor
4 uses
4 complications
measured values
derived values
4-12
Prox lumen - open 25cm tip in RA
measure cvp
1.5ml
Draw traces as inserted and wedges thru
diagram page 35
scaler of 40mmhg, RA 0-4, RV 25 -2 PA
Resembles trace CVP in RA
Thermistor situated?
4cm prox tip
1 assessment of volume status CVP unreliable
2 Sampling mixed venous blood calc shunt fraction
3 Measure CO using thermodilution
4 Derivation of CV indices such PVR DO2 and uptake
Arrhythmia on insert
knotting in rv
balloon rupture
Pulmonary infarction
Measured
CVP PAP PCWP CO SVO2
Derived
CI SV SVI SVR SVRI PVR PVRI
1.9 b PAC other
PAFC swan and ganz in 970
7 or 7.5G and 110cm long
Balloon tip capacity 1.5ml
Before insert - traducer and zero - wave up down appear monitor - ensure corrected to correct
advamced 20cm before inflate baloon
RA - CVP mon rv systol 25
1.10 Paeds resus
Compressions
Doses
5 rescue breaths
Compressions 15:2
Doses
Adren
10mcg kg .1ml/kg of 1:10000
IO dose 10ug
Amiodarone 5mg / kg
Atropine 20mcg / kg
Dose DCCV 4 J Kg
Weight 2x age + 4
Fluids 20ml kg
IO after 3 attempts
1.10
b
Hs
Ts
Hypoxia
hypovolaemia
hypo / hyper kalaemia
hyothermia
Tension PTX
Tamponade
Toxins
Thromboembolism
1.13 a
Anaphylaxis
Sim station 10 points
- Checks vitals + calls critical incident
- call 4 help
- 100% O2
- Check ETT
- Auscultate
- Ask for adrenaline
- Check drip give floods
- look cutaneous signs
- Admin Anaphylaxis adjuncts
- Reassess vitals + repeat adren prn
1.13 b
recognising anaphlylaxis
6 features
1 Tachycardia
2 Hypotension
3 Severe bronchospasm
4 Low sats - im gas exchange & reduced peripheral perfusion
5 low etco2 reduced pumonary perfusion
6 Unresponsiveness to ephedrine metaraminol
1.13 Anaphylaxis QRH steps
❶ Call for help. Note the time. Stop or do not start non-essential surgery.
❷ Call for cardiac arrest trolley, anaphylaxis treatment pack and investigation pack.
❸ Remove all potential causative agents and maintain anaesthesia.
• Important culprits: antibiotics, neuromuscular blocking agents, patent blue.
• Consider chlorhexidine as cause (impregnated catheters, lubricants, cleansing agents).
• Consider i.v. colloids as a possible cause.
• Change to inhalational anaesthetic agent (if not already).
❹ Give 100% oxygen and ensure adequate ventilation:
• Maintain the airway and, if necessary, secure it with tracheal tube.
❺ Elevate patient’s legs if there is hypotension.
❻ If systolic blood pressure < 50 mmHg or cardiac arrest, start CPR immediately.
❼ Give drugs to treat hypotension (Box A):
• Hypotension may be resistant and may require prolonged treatment.
• Give adrenaline bolus and repeat as necessary.
• Consider starting an adrenaline infusion after three boluses.
• If hypotension resistant, give alternate vasopressor (e.g. metaraminol, noradrenaline
infusion +/- vasopressin)
• Give glucagon in ß-blocked patient unresponsive to adrenaline.
❽ Give rapid i.v. crystalloid: 20 ml.kg-1 initial bolus, repeated until hypotension resolved.
❾ Give hydrocortisone as part of resuscitation (Box B).
❿ If bronchospasm is persistent, consider → 3-4
⓫ Take 5-10 ml clotted blood sample for serum tryptase as soon as patient is stable.
• Plan for repeat sample at 1-2 hours and >24 hours.
⓬ Give chlorphenamine when feasible (Box B).
⓭ Plan transfer of the patient to an appropriate critical care area. Note tasks in Box D.
⓮ Prevent re-administration of possible trigger agents (allergy band, annotate notes/drug chart)
Drugs as per QRH for hypotension
Box A: DRUGS TO TREAT HYPOTENSION IF CARDIAC ARREST → 2-1
• Adult adrenaline: i.v. 50 μg (= 0.5 ml of 1:10 000)
i.m. 0.5 mg (= 0.5 ml of 1:1000) if i.v. not possible
• Paediatric adrenaline: i.v. 1.0 μg.kg-1 (0.1 ml.kg-1 of 1:100 000)
[1:100 000 solution made by diluting 1 ml of 1:10 000 up to 10 ml]
• If no i.v. access, intraosseous adrenaline dose same as i.v.
• Suggested adrenaline infusion regimes (adult):
5 mg in 500 mL dextrose = 1:100 000, titrate to effect
3 mg in 50 mL saline. Start at 3 ml.h-1 (= 3 μg.min-1), titrate to
maximum 40 ml.h-1 (= 40 μg.min-1)
- Glucagon (adult): 1 mg, repeat as necessary
- Vasopressin (adult): 2 units, repeat necessary (consider infusion)
1.13 Anaphylaxis
C Other drugs
Box B: OTHER DRUGS • Hydrocortisone i.v. doses: • Adult: 200 mg • Child 6-12 years: 100 mg • Child 6 months-6 years: 50 mg • Child <6 months: 25 mg • Chlorphenamine i.v. doses: • Adult: 10 mg • Child 6-12 years: 5 mg • Child 6 months-6 years: 2.5 mg • Child <6 months: 250 μg.kg
1.13 Anaphlyaxis
D Dont forgets from QRH
Box D: DON’T FORGET
• Repeat testing for serum tryptase at 1-2 hours and >24 hours.
Store at 4 degrees
• Liaise with hospital laboratory about analysis of samples.
- Liaise with department anaphylaxis lead regarding referral to a specialist allergy or immunology centre to identify the causative agent
- Inform the patient, surgeon and general practitioner.
Report
Inform patient
1.13 e
Physiology of anaphylaxis from Kerry B
Diff Anaphylactic vs anaphlyactoid reaction
Anaphylactic - acute hypersensitivity rxn - previously sensiteised to antigen
Immune med Ige mast cell
med His + LK released mast cell
Not relate to dose
type 1 or immed hypersensitivity
Anaphylactoid - no prior exposure, can occur on 1st exposure, not IgE med, less severe (can be fatal) related to dose of agent
Similar symptoms = sim causative agents rel from mast cell
difficult different clinc
1.13 f
Physiology of anaphylaxis
Acute reaction
1st exposure no symp
ige atnibod develop over 14 days
attached to mast cell
mast cell may have 500000 IgE attach membrane
second and subseq exposure - severe reaction
combines with cell bound IgE
mast cell release contents
severeal mediator rel - symp can produce his alone
symptoms vary mild to severe depending amt histamine rel
anaphylaxis - without protection - old theory 1st exposure used body protection / defences against toxic agent
body without defences for subsequent exposures.
1.14 Monitoring - capnography
a
ID it
Main stream
what is
advantage
Factors affecting response time
Main stream
Cuvette Co2 sesnor - between ett and system
No need sampling
vapour condense on sensor - can result fals high
sense heated 39C
heavier and cumbersome
Adv
No delay,
no loss in gass
no mixing sample w/ inspired
1.14 b
side stream
Side stream
Sensor located main unit
gas aspirated - small pump via sampling tube at rate of 50-150ml min
gas also contain anaes - should be scavenged / return system
Factors affecting response time
1 Response time depend on transit + rise time
2 Transit time depends on length of sample tube
3 rise time depends on optimum flow and size of chamber
- very low flow and large chamber increase rise time
1.14 C
Capnography phases
1 Inspiratory baseline -
should be at 0 as elevated means rebreathing
2
Expiratory upslope
shallow - obstruction
3
Plateau
representing mixing of alveolar gas
if sloped not flat - uneven mixing - COPD
4
Inspiration
Fall to 0
downstroke
1.14 Patterns of capnography on page 57
page 57
1.14 E
Measurement of CO2
Capnometry vs capnography
plotted how
Capnometry measure of Co2 conc during resp cycle
Capnography graphic representation CO2 conc - waveform
plot as EtCO2 vs time
CO2 plot y
Time - X
1.14 F
How does it work
Capnography uses IR absorption Co2
gases molecules 2/= diff atoms absorb rad in IR spec
Co2 strong absorption at 4.26
Spec scope page 58
Amt IR absorb proport to CO2 conc
Electrical output photodetector present partial pressure Co2 in sample chamber
1.14 G
Changes in trace
sudden decrease to 0
sudden decrease low
exponential drop
gradual decrease
Sudden decrease in etco2 to near 0 =
airway disconnection
totally obstructed airway or vent malfunction
Sudden decrease to low level
reduced CO or leak
Exponential drop due to reduced pulmonary perfusion - low CO / PE
Gradual decrease hypervent / hypothermia
gradual increase - hypervent or increase body temp
1.15 a
1 Diathermy uses
2 Physical principle
3 current
4 Why plate large area
5 What happens if plate disconnected + diathermy activated
6 Other problems with diathermy
7
Mono vs Bi
1 High freq A/C
cut or coag tissue during surgery
cutting - sine wave
coag - damped or pulse sine wave
2 High frequency current
(min fx on cardiac and skel muscle)
localised high density current
(current per unit area)
High at forceps at low at earth plates
depending equipment - accetpable level leakage determ
3 0.5- 1Mhz
4 Large plate reduce current density
5 Current flow thru patient and earther thru any metal - attach patient
6 Fire and explosion
pacemaker dysfxn
7 monopolar needs neutral plate
bipolar forceps travels one limb and leaves other other
bipolar - lower power
1.15 b
Safety features
Precautions prevent hazards to patient
1 Outer case is earthed
2 Isolating capacitor - high impedance to low frequency current
3 Floating circuit
active electrode and neutral electrodes are isolated from earth connection
‘earth free circuit’
1 Good connection to neutral plate to patient
2 not activating diathermy until active electrode contact with tissues
3 Regular servicing
1.15 C
Pictures
CF - leakage current <10amperes
BF Higher protection vs shcok than provided w/ B
LIKE cf - FLOATING RESPECT TO EARTH
B type = non cardiac grounded applied parts
come into contact with patient
C type = heart
f floating - isolating
CF is for cardiac application - higher degree protection vs shock than BF
1.16 A Radiology CXR
CT ratio
And heart borders in page 66
Normal cardiothoracic ratio
1.18 Awarenss communication station
a marking sheet
15 points
1 introduce
2 Discuss in presence of witness
3 confirms facts
listens to hix find out what does recollect
4 apology
5 advise precaution measure taken
6 unstable - stabilised careful drug - possible during that had awareness
7 any pain during it
8 rare, complcation with trauma patients
9 interview senior consultant
10 Follow up
11 Psychological support
12 Ressures future ga safe
13 advise documented and write gp
14 want to know anything more
15 polite rapport
1.18 b
Memory
Explicit memory - concsiou awarenss w/ recall +/- pain
implicit - perception during anaes w/out recall or concious awareness
poss confused ketamine
high
obs and trauma
tiva
human error judgement or faults
1.18 C
Key points
See patient early
ward nurse / reposible
apology not guilt - helps patient
get facts right
find out what recall
explanation and conduct and safety
special interest boss
reassure
1.19 a
Anatomy - intercostal nerve block
Anatomy of chest on page 72
page 72 1-8
1.19 b
3 structures passing thru IC space
how aranged
i 3 strctures
how arranged
ii
how many veins in each space
iii Indications
iv which 2 muscles are IC nerves and vessels found
V
Complications
vi what type of nerve is IC
i
V
A
N
above down
ii
1 posterior
2 anterior
iii
Thoracic surgery breast upper abdo procedures - chole rib # IC drain
iv
NV bundle between internal IC + Inner IC muscle
v PTX intravasc injection Bleeding nerve damage LAST
vi
Mixed spinal
1.19 c
Intercostal nerves
emmerge where
divsions?
what they do
connect what
where does ant division pass
Where doe t1 t2 etc provide
Prob with block?
t1-t12 Spinal nerves
emerging intervertebral foramina divide into anterior post div
post - sens and motor to parvert region
connect symp chain
anterolat to vert body and comm thru rami communicantes
ant division ic space - ICN runs costal groove inner surf inf border of body rib = protection
T1 - UL
T2 Intercostbrachail
T3-6 thorax
t7 down - abdominal wall
t11 t12 - subcostal
Block - no viscera cover
D/T vascularity - high propensity for LAST
Higher peak plasma vs other blocks
Cranial Nerves and how to test
1 Olfactory - smell
2 Optic
Pocket acuity chart - seperately visual fields Diam pupils Direct + Consensual Accom reflex
3 4 6 Oculomotor Trochlear Abducens Ex ox muscle SO4 LR6 3 - levetor palpebrae - eye elevator - PS fibre w/ 3rd - a/w disrupt ps activit - pupil dilate
5
trigeminal -
mastication + sensory innervation
feel masseter bulk - clench teeth
sense Opthalmic max mandib pin prick fine touch cold + warm
corneal reflex V + VII
Cotton bud touching cornea - observe reflex blinking
7 Facial
look creases
raise eyebrows, shut eyes tight, show teeth bloow air out
lesion peripheral - entire half face
central - upper half spare - dual innervation
8 Vestbicoc hearing and balance - hearing tested bilat connect precise diagnosis difficult whisper webber rinne audiogram
9 + 10 Glossopharyngeal + Vagus Test together hoarseness swall dific aa look palate - uvula reamains midline soft palate rises symett unilat - uvula drawn to normal side gag sens ix motor x - stim back throat
11 Accessory
trapezius + SCM
wwasting muscle
shrug shoulder and turn head
12 hypogloassoal
tongue muscle - ask prtude - wasting fasic deviation
unilat lesion - towards affect side
