Equipments Flashcards
How is oxygen manufactured?
Fractional distillation of air or the use of an oxygen concentrator in which zeolite mesh absorbs Nitrogen. Leaving about 97% oxygen.
Storage of oxygen?
- Gas in cylinders
- Liquid in VIE
Properties of the oxygen cylinder ?
- Black body and white top
- Stored at 13,700kPa or 137bar
- Varies between 12000-17000kpa
State all the possible cylinder sizes?
C - 170 L
D - 340 L
E - 680 L
F - 1,360 L
G - 3,400 L
J - 6800 L
What are the properties of VIE?
- Pressure 10 - 17bar
- Safety valve
- Pressure regulator to 4bar
- Liquid oxygen at -160 to -180 degrees
- Inner stainless steel
- Outer pure steel
- Insulating perlite
- Evaporator
What is the VIE?
- Allows storage of cryogenic liquids
- Oxygen, Nitrogen & Argon
What is the critical temperature of oxygen?
- 118 degrees
What are the physiochemical properties of oxygen?
- Boiling point -182 degrees
- Critical temperature- -118
- Critical pressure 50bar
Define critical temperature?
This is the temperature above which vapour of the gas cannot be liquified regardless of the pressure applied
What’s the critical pressure of a gas?
The critical pressure of a gas is the pressure require to liquify the gas at its critical temperature.
What is negative pressure ventilation?
Occurs within a chamber and this pressure is applied to the thorax
Positive pressure ventilation by functions?
- Trigger
- Limit
- Cycle
What is tigger ventilation?
- The event starting each breath
- No spont effort - Time - Set RR
- Spont effort - Minimum flow
What is limit controlled ventilation?
The factor that controls respiratory flow.
Ventilation by cycle control ?
- changing from insp to exp
- cycling signals include; Time, volume & flow
Classification of breathing systems?
- Open
- Semi-open
- Semi -closed
- Closed
What are the properties of Mapleson-A system?
- Efficient during SV
- Inefficient during CV
- FGF must equal patient’s alveolar MV to avoid re-breathing of CO2
- The co-axial version is called a Lack circuit
Why is Mapleson-A inefficient during CV?
Gas is forced from through the APL valve due to high pressure in the system. Thus system becomes inefficient
Scavenging and the Lack circuit (Co-axial Mapleson-A) ?
This makes gas scavenging much easier
What are the characteristics of Mapleson B circuit?
- Inefficient with both SV & CV
- During exhalation a mixture of FGF & alveolar gases pass via the APL valve
- During inspiration mixed FGF & retained alveolar gas is inspired
- FGF 2-3 times pts MV
What are the characteristics of Mapleson C circuit?
- Inefficient for SV & CV
- Used in the emergency setting
What are the characteristics of the Mapleson D system?
- Consists of a co-axial bain modification
- Inefficient for both SV & CV
- More fresh gas will be available with longer expiratory pauses
- At least 2 times the mV is required to prevent re-breathing (In both CV & SV)
What are the characteristics of the Mapleson D system?
- Consists of a co-axial bain modification
- Inefficient for both SV & CV
- More fresh gas will be available with longer expiratory pauses
- At least 2 times the mV is required to prevent re-breathing (In both CV & SV)
What are the characteristics of Mapleson F?
- Modified T-piece by jackson & Rees
- This is a low resistance circuit
- Used in paediatric anaesthesia
What are the safety features of an anaesthetic machine ?
- Vigilant & well-trained anaesthetist
- Power supply & back-up battery