EMO Vaporiser and Oxford bellows

1. EMO VAPORIZER AND
OXFORD BELLOWS
Dr.Mrunmayai Jadhav
Moderator : Dr Gauri Gangakhedkar

2. EMO (EPSTEIN MA CIN TO SH O XF O RD) VA PO RISER -
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- CONCENTRATION CALIBERATED
- DRAW OVER WITH LOW RESISTANCE
- FLOW OVER (WITH WICKS)
- VARIABLE BYPASS
- THERMOCOMPENSATED
- AGENT SPECIFIC

3. CO N STRUCTIO N
◦ Emo Vaporizer is 23cm in diameter and 24 cm in height
◦ It weighs 6.5kg with water compartment full (1200ml of water)
◦ Annular ether vaporizing chamber lined with wicks
◦ Relatively large air passages offering low resistance to breathing
◦ Temperature compensating unit –Ether capsule(bellows) containing
liquid ether – (lasts for 10 years !).
◦ Filler port – to fill the volatile agent
◦ Dial Concentrator
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P A R T S O F E M O

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7. THERMO CO MPEN SA TIO N
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1. Water Jacket – Temperature Buffer
2. Altered flow - Flow alteration at the outlet of the vaporizing
chamber via the ether capsule (bellows).
Temperature Indicator
◦ At normal working temperature (20–25°C) metal top and black
band will be seen.
◦ When temperature is too high (over 32°C) ,the indicator shows
red band.

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• F l o a t A s s e m b l y
• 1 5 0 m L i s r e q u i r e d t o f i l l i t t o t h e
‘ E m p t y ’ m a r k – B l a c k b a n d ( t h i s
b e i n g t h e a m o u n t s o a k e d u p b y
t h e w i c k s )
• F u r t h e r 3 0 0 m L t o r a i s e t h e l e v e l
t o ‘ F u l l ’ – R e d B a n d

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• C l o s i n g m e c h a n i s m w h i c h s e a l s o f f
t h e e n t r y t o t h e e t h e r c h a m b e r
w h e n t h e c o n t r o l i n d i c a t o r i s i n
t h e ‘ t r a n s i t ’ p o s i t i o n .
• I n c o r p o r a t e d i n t h e c l o s i n g
m e c h a n i s m i s a n i n l e t r e l i e f v a l v e ,
w h i c h a l l o w s a i r t o e n t e r t h e
i n h a l e r i f t h e m a i n a i r i n l e t
b e c o m e s b l o c k e d

10. HO W TO SETUP A N EMO VA PO RIZER
◦ When supplied, the water jacket is dry and must be filled
with approximately 1200 mL of cold distilled water via the
filler.
◦ Mark I EMO’s have aluminum water jackets , so the water level must be checked
every 3 months because chemical action may lead to generation of gas which may
damage other parts of the inhaler.
◦ Mark II, Mark III, Mark IV EMOs have stainless steel jackets and need only yearly
water level checks.
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11. HO W TO SETUP A N EMO VA PO RIZER
◦ When filling the control pointer must be turned to the zero position rather than
to the ‘transit’ position so that air can escape from the vaporizing chamber.
◦ As ether is poured in, the filler must be held down.
◦ The inhaler must not be overfilled otherwise the wicks will be covered and
vaporization of the ether will be decreased.
◦ 150 mL is required to fill it to the ‘Empty’ mark , further 300 mL to raise the level
to ‘Full’.
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13. HO W TO CHECK A N EMO VA PO RIZER?
C H E C K I N G T H E L E V E L I N D I C A T O R ( i n T r a n s i t M o d e )
It is checked by inverting the inhaler (in transit mode),the indicator should fall freely to
full position.
C H E C K I N G F O R A N Y L E A K S ( i n T r a n s i t M o d e )
◦ Outlet is blocked
◦ Inlet is connected bellows
◦ Filler is held open
◦ The bellows are compressed - on doing
so no air should escape
◦ Filler then released and Control pointer
is turned to 10% and this is repeated to
check that the filler is not leaking
◦ Outlet is attached to the bellows
◦ Inlet is blocked
◦ Control knob is set at ‘2’
◦ If the safety release valve is working
correctly, air can be heard hissing
through.

14. T h e A C C E S S O R I E S
EMO vaporizer is mainly used as part of Tri-service apparatus in Field Anesthesia
consisting of –
◦ EMO vaporizer
◦ Oxford Miniature Vaporizer (OMV)
◦ Oxford Inflating Bellows (OIB)
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15. O x fo rd Infla ti ng B ello ws (O IB )
◦ Consists of an inlet connection and valve,
the bellows in the middle, an outlet valve
and outlet connection.
◦ The valve consists of a disk of metal that lifts
by air flow and falls by gravity.
◦ An oxygen inlet connection.
◦ A magnet - used to immobilize the outlet
valve when a non-rebreathing valve is used
for control ventilation.
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16. S P O N T A N E O U S V S C O N T R O L L E D V E N T I L A T I O N
◦ Originally designed for use with a simple spring-loaded expiratory valve.
◦ This arrangement works well with spontaneous respiration, but is less satisfactory for
controlled ventilation.
◦ An automatic non-rebreathing valve is essential for controlled ventilation.
◦ But compression of the bellows during controlled respiration will produce a full
deflection of NB valve during inspiration & in order to draw the valve back and hence
permit the patient to expire to the atmosphere, a very small amount of air must pass
back towards the bellows.
◦ If the outlet flap valve of the bellows unit is not immobilized, air will be unable to pass
back and the non-rebreathing valve will stick in the inspiration position.
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19. The magnet holds the expiratory valve open. So the magnet MUST be fitted if a non-
rebreathing valve is being used.
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NOTE : The magnet on the OIB should never be used to immobilize the distal flap valve when
a spring loaded expiratory valve is used – it would lead to rebreathing into the bellows.

20. WHA T CA N HA PPEN ?
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21. PRIN C IPL ES F O R A RRA N G EMEN T
◦ If vaporizers are to be placed in series, the vaporizer for the more
volatile agent should be placed upstream (i.e. further from the patient)
from the vaporizer for the less volatile otherwise condensation of the
less volatile agent will occur in a cooler downstream vaporizer. EMO
should therefore always be upstream of the OMV.
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The bellows should be placed between the vaporizer and the patient. If air is blown through the vaporizer, the
concentration delivered may be greater than indicated. This is due to the large internal volume of the EMO
vaporizer.
O2 and N2O (when used) should always be upstream the vaporizers. This avoids the dilution of the vapour,
which will occur if the gas is introduced downstream. The oxygen inlet on the OIB is intended for use in
resuscitation.

22. THANK YOU !
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