Monitoring and Equipment Flashcards
What are cylinders made of?
Molybdnum steel - old style
Aluminium alloy wrapped in kevlar - new cylinders
Which cylinder cant be taken into MRI scanner
Molybdnum steel cylinders
ferromagnetic and would be drawn into the scanner
What is the pressure inside a size E cylinders
13700 kPa /137 bar
What does the tare weight refer to
Tare weight is the weight of the empty cylinder
What does a bodok seal do
Prevents a leak of gas between gas clinder and the cylinder block
What is the pressure in the Nitrous oxide pipeline
4 bar or 420kPa
On the anaesthetic machine what should be the minimum flow in the oxygen bypass circuit
30L/min
What is the function of the pressure relief valve on the back bar of the anaesthetic machine
to prevent damage to the vaporisers
to prevent damage to the rotameters
NOT PATIENT
At what pressure does the pressure relief valve on the back bar open
30-40kPa
What are the internal and external diameters of the common gas outlet on the anaesthetic machine
15mm and 22mm
What are the safety mechanisms to prevent the wrong gas coming out of the common gas outlets of the anaesthetic machine
Schrader valve pipeline
Non Interchangeable Screw Thread (NIST) on pipelines
Pin index classification
Colour coding of pipelines, cylinders and connections
What are the wavelengths of light emitted from the diodes in pulse oximeters
660nm and 940nm
How often do diodes flash
approx every 30 seconds
When might a pulse oximeter be inaccurate
CO poisoning
hypotension
peripheral vasoconstriction
arrhythmia
nail varnish
extraneous light
What does soda lima consist of
NaOH (4%)
calcium hydroxide 80%
bound h20 16%
What is the mesh size in the soda lime and why
4/8 mesh size
if granules are too small there will be too much space between them so resistance to flow of gas will be too high
What is the mapleson D circuit also known as
Bain circuit
inefficient for SV more efficient for CV
How much FGF is needed in a bain circuit in SV and CV
SV 2x MV
CV can be as low as 70ml/kg
Why is the bain circuit more efficient in CV
due to long expiratory pause more fresh gas flow ill be available in the outer tubing
What information is engraved on the gas cylinder
5 pieces of info
- unique serial number
- chemical formula of the gas on shoulder and valve block
- tare weight
-test pressure
-dates of tests performed
What size cylinders do we commonly use in anaesthetic practice
SIZE E are used on the anaesthetic machine
Size J cylinders normally used in cylinder manifolds
Differences betxygen ween oxygen and nitrous oxide cylinders
oxygen
- 137bar/13700kpa
n20
- stroed in liquid phase with vapour on top
-4400kpa
- due to critical temp is 36.5 C
- vapour used up first
- gauge continues to read 4400kpa until liquid has been used up and vapour remains
- need to assess how much is left via the weight
What is critical temperature
defined as the temp above which the substance can not be liquified
n20 36.5 C
What is pseudocritical temp
Used for gas mixtures such as entonox
the psuedocritical temp is the temp when there is a risk the gas mixture may separate out into its different gases
entonox -5.5C - if used concn of high o2 conc and then n20. rewarming cylinder will reverse this
What is the pin index system and why is it used
safety system to stop the wrong cylinder being attached to the anaesthetic machine
each gas has its own pin index on the yolk
pins and holes need to match
How are cylinders tested
cylinders in use are tested at regular intervals of 5 yrs
1 out of 100 cylinders goes under tensile strength testing
internal endoscopic examination to look for cracks and defects
cylinders are subject to high pressure of 22,000kPa
