OSCE 5

Question 1

5.14 Invasive blood pressure monitoring

i Finding faults with their system

Answer 1

i
1. Infusion bag not under pressure

2. Transducer loosely attached
3. Wrong tubing - not stiff
4. Too many 3 way taps
5. Cannulla to narrow
   (should be 20)

Question 2

5.14 A line

ii What info from art waveform

Answer 2

ii

1. Heart Rate
2. SBP
3. DBP
4. Contractility
5. SVR
6. Vol status

Question 3

5.14 A Line

iii describe zeroing a line

Answer 3

3 way tap opened to atmosphere
opening 3 way stopcock between patient and transducer
zero on monitor

Question 4

5.14 a line

iv how would calibrate for high pressure

Answer 4

iv
Connect to aneroid manometer
sterile tubing
manometer pressure raised to 100+200
Display - read same pressure and transducer

Question 5

5.14 v Normal waveform
underdamped
overdamped

Answer 5

v
Normal -
Underdamped - goes very high
Overdamped - too low

Question 6

5.14 vi

What happens to overdamped

Answer 6

Overdamped - mean unaffected
Under read systolic and
over reads diastolic

Question 7

5.14 Art line shpiel

What does it consist of

What is the purpose of a fluid filled system

Why normal saline

Flushing system

Answer 7

Arterial cannula
Catheter Tubing
Transducer
Pressurised flush
Monitor display reading + waveform
Cable connecting transducer to monitor

Fluid provides a means of transmitting pressure in artery to transducer
Saline used - Flush
viscosity influence natural frequency
high viscosity than n saline = overdamping

Flushing system pressurised to 300mmHg - continuous slow flow fluid
3-4 ml hr
preferably heparinised - minimise clot formation in catheter

Question 8

5.14 A line spiel

Cannula

Tubing

What does the upslope indicate
downslope
swing

Zero calibration

Answer 8

Wide stiff
- for accurate rep pressure
fluid correct info to strain gauge

• increase compliance = reduce natural frequency

Number 3 way taps = minimum
normally 1 between cannula and tubing and another between tubing and transducer

Tubing
Short
stiff walled
free bubbles

Upslope = contractility
Downslope  = SVR

Increased swing = reduced preload

Reduced effect atmospheric pressure on measured pressure

elim gradient drift - calibration higher pressure
transducer - ref to zero ref = level of LV
mid ax line left side

overdamped - 
air bubble c
lot 
catheter kinking stopcock
complaint long tubing