Equipment

Front 1

Categorise oxygen delivery devices

Back 1

1. invasive - ETT

2. Non-invasive

- fixed performance

- variable performance

--> performance vary with FGF and inspiratory flow rate

Front 2

Fixed performance device

Back 2

FGF > peak inspiratory flow --> constant FiO2

Require high gas flow --> dry mucous membrane

e.g. venturi mask

Front 3

Bernoulli principle

Back 3

gas forced thru stricture increases gas flow velocity

(fall in potential energy (pressure) --> increased kinetic energy (velocity) )

Front 4

variable performance devices

Back 4

e.g. NP, HM, non-rebreather mask

Front 5

Nasal prongs

Back 5

oxygen reservoir = nasopharynx

max FiO2 44% at 6L/min

degree of O2 enrichment depend on:

- oxygen flow rate

- peak inspiratory flow rate

- minute ventilation

- nasal vs oral breathing - expiration more important (nasal expiration --> clear reservoir)

Front 6

Non-rebreather mask

Back 6

- 2L reservoir bag

- One way valve - force inspiration from reservoir, prevent air entrapment

- FiO2 60-90%

Front 7

what does the size of an ETT measure

Back 7

internal diameter

Front 8

ideal ETT cuff pressure

Back 8

25-30cmH2O

Front 9

at what position is the tip of the ETT located

- Portex

- Parker Flexi-tip

Back 9

Portex - 3 o'clock

Parker - 12o-clock (make easier to insert)

Front 10

Tracheal tube connector

Back 10

set dimensions, set by ASTM/ ISO standards

patient end - size set as per ETT size

machine end - 15-mm male fitting

Front 11

Tapered connector

Back 11

- connector b/w ETT (15mm) and circuit or facemark (22mm)

- tapered end

- ID 15mm ( fit ETT)

- ED 22mm (fit facemask)

Filter - same tapered end (15mm ID, 22mm OD)

Front 12

aintree catheter

Back 12

"turtoise" catheter

56cm long, 4.7 mm ID

- help convert LMA to ETT

- max size bronch = 4.5cm

- smallest ETT #7 railroaded over aintree

- 15mm attachment to allow oxygenation through aintree

- dont inserted more than 26cm at teeth

Front 13

Cook exchange catheter

Back 13

= long blue catheter

83cm length

attachment allow oxygen to be delivered (connect directly to green O2 circuit)

Front 14

optimal cuff pressure in LMA

Back 14

60mmHg

Front 15

max eat size fit down lma

- 3

- 4

- 5

Back 15

3-4 = 6ETT

5 = 7 ETT

Front 16

iLMA

Back 16

size 3, 4, 5 LMA all same internal diameter

accept up to size 8 ETT

iLMA ETT come in 6 to 8mm

iLMA longer than normal ETT

Front 17

Proseal LMA c/w classic

- advantage

- disadvantage

Back 17

Advantage

1. higher airway seal pressure (30-35cmh2O c/w 20cmH2O for classic) --> better ventilation (even better than supreme LMA) - ventral cuff pushed by dorsal cuff into periglottic structures to improve seal

2. gastric port

3. successful use in difficult and rescue airway

4. incorporated bite block

Disadvantage

1. higher cuff pressures 60cmH2O (but no increase in mucosal pressure)

Front 18

Allen test - rating delay

Back 18

Normal : 7 sec

Borderline 7-15sec

Abnormal >15sec

low sensitivity and specificity

Front 19

How does pressure transducer in arterial line work?

Back 19

change in pressure proportional to change in length of diaphragm which is proportional of change in resistance

change in resistance detected via wheatstone bridge and converted to electrical change

Front 20

Definition of dampening

Back 20

reduction in amplitude of oscillation in an oscillating system, caused by energy loss.

described as dampening coefficient

--> underestimate SBP + overestimate DBP, MAP same

Front 21

Factors affecting dampening

Back 21

1. inertance = viscous friction within the fluid column

2. impedance = changes in caliber of fluid path

3. compliance = elastic catheter material or air bubbles

Front 22

What is resonance?

Back 22

tendency of system to oscillate with greater amplitude at the natural frequency than at other frequencies.

diaphragm will have natural frequency (tendency to vibrate). If natural frequency = HR then increased lengthening for any change in pressure.

aim to have frequency well above same frequency as HR

--> overestimate SBP, underestimate DBP, MAP same

Front 23

Dampening

Back 23

optimal dampending: 0.64

best glance b/w speed of response and accuracy

ensures:

1. minimise amplitude distortion

2. maximal frequency response

3. Phase distortion minimised

Front 24

system with high natural frequency

Back 24

e.g. high resonance

will cope with a wide range of dampening

damping coefficient incr as damping incr

Front 25

Causes of too much damping

Back 25

1. long rigid tube

2. blocked sample line (kinks or bubbles)

3. arterial vasospasm

Front 26

problem with bubbles in arterial line

Back 26

damping increase, resonance decrease

because it does both, inaccurate reading and SBP can be high or low

Front 27

2 steps in calibrating an arterial line

Back 27

1. zeroing - remove atmospheric pressure

2. Leveling - specific position on patient's body (level of right atrium)

Front 28

slurring systolic upstroke in arterial line trace

Back 28

suggest AS

Front 29

Differences in arterial pulse pressure trace as you move further away from heart

Back 29

1. high systolic pressure

2. further dicrotic notch

3. lower diastolic pressure (wider pulse pressure)

4. later arrival of pulse

NB - MAP doesn't change much

Front 30

how do you determine the size of the reservoir bag in a circuit

Back 30

patient's peak inspiratory flow rate

Front 31

Compare having a vaporiser inside or outside the circle circuit

Back 31

Inside not as good as outside

Problem with inside:

1. need low resistance inside vaporise to allow air to go thru

2. risk of high volatile concentration (gas "to-and-fro" thru vaporiser)

3. slow onset in spont breathing pt as concentration of violate dependent on pt's inspiratory flow rate

Good about outside vaporiser:

1. required concentration achieved by adjusting vaporiser

2. never deliver more than max volatile concentration

Front 32

Disadvantages of circle system

Back 32

1. small tidal volumes may not generate enough pressure to open valves effectively

2. Dead space in y-absorber (cause re-breathing)

3. Expensive and bulky

4. unstable is used closed

5. slow change in inspired VA conc with low flows or out-of-circuit vaporiser

6. resistance to breathing - soda lime and valves

7. inhalation of soda-lime dust

Front 33

Advantages of circle system

Back 33

1. economy of gas consumption

2. warm + humidify

3. reduced atmospheric pollution

4. efficient use of soda lime

Front 34

Mapleson E system - draw

Back 34

Front 35

FGF requirement in mapleson E systemm

Back 35

1.5 - 2 x MV in spontaneously breathing patient

Front 36

advantages of t-piece

Back 36

1. compact

2. inexpensive

3. No valves

4. Low dead-space

5. low resistance to breathing

6. Economical for controlled ventilation

Front 37

Disadvantages of T-peice

Back 37

1. heavy, difficult to keep connected to ETT in small kids

2. twisted bag may impede breathing

3. high FGF requirements

Front 38

Back 38

Air leak - loose connection b/w sampling tube and capnograph/ broken connection or filter

Front 39

Back 39

Bronchospasm, COPD, emphysema, obstructed ETT

Front 40

Back 40

ETT cuff leak/ deflated cuff

ETT in hypo pharynx

partial obstruction

Front 41

Describe process for cell salvage

Back 41

1. collection - mixed with anti-coagulant

2. filtered - remove debris/ clot

3. centrifuge - remove plasma - inc platelet and clotting factors + addition of N/S

4. stored in re-infusion bag for infusion

Front 42

Hct of RBC produced by cell salvage

Back 42

60-70%

Front 43

Advantages of cell salvage

Back 43

1. reduce autologous blood transfusion

- finite resource

- less cross matching

- risk of early or delayed reaction to autologous blood

- risk infection

- immunosuppression from autologous blood

2. Acceptable to Jehovas witness

3. minimise risk DIC with rein fusion

Front 44

Disadvantage of cell salvage

Back 44

1. machinery, personnel, training

2. NO platelets, some clotting factors

3. inefficient - 60% salvaged blood saved

4. C/I : betadine, malignant cells, infection, amniotic fluid, sickle cells disease

5. incorrect washing --> cell lysis and prob on rein fusion

6. air embolism on reinfusion

7. can't be pumped back --> haemolysis

Front 45

What is CLABSI?

Back 45

laboratory-confirmed blood stream infection related to presence of central line or umbilical catheter that is in place either at the time of or within 48hr before the onset on an infection

Not related to infection at another site

Front 46

Modifiable and non-modifiable risk factors for CLABSI

Back 46

Modifiable:

1. type - polyurethane < silicone

2. lumens - more lumen > less lumen

3. frequency of hub manipulation

4. location - peripheral < central; subclavian < IJ < femoral

5. type: tunnelled < non-tunnelled

6. duration

7. emergency > elective

8. skilled < un-skilled operator

9. TPN

Non-modifiable

1. child > adults

2. disease - immunocompromised, CVS, GI disease

3. male

Front 47

Sources of catheter infection

Back 47

1. extra-lumen (skin --> migrate down CVC)

2. Intra-lumen (more common)

Front 48

What are the contents of soda lime

Back 48

80% - calcium hydroxide

15% - water

4% - Na hydroxide

1% - K hydroxide

Front 49

Max absorbed CO2

Back 49

26L of CO2 / 100gram absorbent

Front 50

Disadvantages of soda lime

Back 50

1. increase time to anaesthetic onset

2. CO

- from CHF2 terminal groups

- desflurane most CO

- production promotional to time VA in contact with CO2 absorbent

- more common in anaemic pt, long surgery

3. compound A

- nephrotoxic in rats, not proven in humans

- need 1.25 MAC over 4-8 hr at 2L/min FGF

- sevoflurane

4. Trichloroethylene

- react with soda-lime to produce toxic compounds (dichloroacetylene - cranial neurotoxin)

Front 51

Factors incr CO production

Back 51

1. Agent DEs > en > iso

2. Dryness of absorbent

3. Baralyme

4. incr temp

5. low gas flow rates

Front 52

Factors that incr compound A formation

Back 52

1. baralyme

2. dehydration of baralyme

3. hypercapnia

4. low flow rates

5. incr temp

6. fresh absorbent

NB - soda lime dehydration decreases production of compound A from sevoflurane

Front 53

what are the waves of the CVP trace and what do they mean?

Back 53

A - atrial contraction. none in AF. incr in TS, PS, pul HTN

C - tricuspid valve budge into right atrium - isovolumentric contraction

x descent - atrial relaxation

V - incr atrial pressure before tricuspid valve open (end of RV systole). prominent in TR

y-descent - atrial empty blood enter ventricle

cannon wave - large wave not correspond to a,v, or c --> complete heart block or junctional arrhythmia

Front 54

Cause of cannon a wave

Back 54

AV dissociation + VT

Front 55

Monophasic waveform in defibrillator

Back 55

-shock delivered from one vector

-no ability to adjust for patient impedance

-graphically shown as current vs time

Front 56

Biphasic waveform in defibrillator

Back 56

- shock delivered to heart via two vectors

- lower current required c/w monophasic

- two types of waveforms

Front 57

TOE 4 chamber view

- angle used

- diagnostic uses

Back 57

Angle: 0-10degree

Primary diagnostic uses

- chamber enlargement/ dysfunction

- LV regional wall

- MV and TV

- intracardiac mass

Front 58

TOE 2 chamber view

- angle

- diagnostic uses

Back 58

Angle: -80-100 degree

Diagnostic uses:

- LA appendage - mass/ thrombus

- LV apex

- LV systolic dysfunction

- LV regional wall - anterior and inferior wall

Front 59

TOE ME AV Short-axis (SAX) view

- angle

- diagnostic uses

Back 59

Angle: 25-45 degree

Diagnostic uses

1. AV morphology

2. AS/ regurg

3. coronary arteries

4. air in roof of LA

Front 60

Microshock definition

Back 60

- induction of VF by small electrical currents (below the threshold of skin sensation)

- requires small area of contact with heart muscle so current density high despite low current

- = <10 uAmps

- e.g. central line with a faulty transducer attached

Front 61

RCD (residual current device)

Back 61

- detect difference b/w active and neutral wire.

- leak >5-10mA --> trip RCD --> stop current flow

Front 62

Disadvantages of RCD

Back 62

1. Not protect against microshock

2. trip electricity to whole theatre complex until faulty device removed

3. will not detect faults in electricity pass thru body and back thru neutral wire (rare)

Front 63

Line isolation monitor - how does it work

Back 63

- floating circuit with no earth

- isolation transformer with 2 coils

- can't form circuit by connecting to earth

Front 64

Advantages of line isolation monitor

Back 64

1. protect against MACROshock

2. does NOT cut off electricity supply to machines

Front 65

Disadvantages of line isolation monitor

Back 65

1. require two breaks in circuit to cause macroshock

2. only detect problem with wire A, B and earth; NOT wire A, B and other metal covering

3. does not protect against MICROshock

Front 66

what do you need for cardiac protected area

Back 66

- equipotential earthing+ either RCD or LIM

Front 67

Types of electrical damage

Back 67

1. burns

2. ignition of a flammable substance

2. electrocution

Front 68

Injuries possible in electrical damage

Back 68

1. depolarisation of muscle cells - VF, systole

2. vascular: thrombosis, compartment synd, rhabdomyolysis

3. neuro: peripheral nerve inju

4. renal: myoglobinuria

5. other: trauma, fire

Front 69

3 elements of "fire triangle"

Back 69

1. ignition source - laser (10%), diathermy (70%)

2. oxidiser - O2, N2O

3. Fuel - ETT, drapes

Front 70

How to prevent fire during tracheostomy:

Back 70

1. lowest possible FiO2, avoid N2O

2. don't use diathermy to incise trachea

3. single lumen ETT with cuff is distal trachea (therefore O2 conc 21% on tracheal incision)

4. Saline in ETT cuff instead of air

Front 71

Management of fire in tracheostomy:

Back 71

1. Disconnect from circuit

2. remove burning material

3. extinguish fire - water or CO2 extinguisher

4. complete tracheostomy

5. ventilate pt with room air and self-inflating bag

6. other: flush saline thru ETT to extinguish fire, assess extent of burn

Front 72

how does Ultrasound work

Back 72

frequency 2-15mHz

Generation:

- crystal in transmitter probe stimulated to vibrate by electrical current

- piezoelectric effect - electrical energy transduced to sound energy

detection

- reflected waves detected by probe

- sound wave --> crystal vibrate --> transduce electrical signal (piezoelectric effect)

Transmission

- absorbed, transmitted through or reflected off

- change in density

- amplitude = brightness

- water = hyper echoic = black

- bone = hypoechonic = white

Front 73

conversion french to diameter

Back 73

Fr = D (mm) x 3

D (mm) = Fr/3

Front 74

tool for detecting awareness under GA

Back 74

Brice questionarrie

1. last thing remember before sleep?

2. first thing remember when awake?

3. Dream?

4. worst thing about operation

5. next worst thing?