Vaporizers are used in anaesthesia breathing system and anaesthesia machines to control anaesthesia depth...

1. PRINCIPLES OF
VAPORISERS
PRESENTER-DR.SHAILENDRA
CO-ORDINATOR0R-
DR GANESH KHANDARKAR

2. Definition
• Vapour:
– A gaseous phase of a substance that is liquid at room
temperature and atmospheric pressure.
• Vapouriser:
– Instrument designed to change a liquid anesthetic
agent into its vapour and to add a controlled amount
of this vapour to fresh gas flow.

3. PHYSICS
• Vapour pressure:
– Pressure exerted by the molecules of vapour on the walls of the
container.
• Saturated vapour pressure:
– Maximum vapour pressure at particular temperature.
– At constant temperature, a dynamic equilibrium is formed between
the liquid and vapor phase so that the number of molecules in the
vapor phase remains constant.
– Represented by density of dots above liquid

4. Vapor pressure changes with varying
temperature

5. Vapour pressure of common
anaesthetic agents
Gas Vapour press. TORR (20 0C)
Halothane 243
Enflurane 175
Isoflurane 238
Desflurane 669
Sevoflurane 157

6. Critical temperature:
That temperature, above which a substance can not be
liquified however much pressure is applied

7. • Boiling Point:
– The temperature(of a liquid) at which its vapour
pressure is equal to the atmospheric pressure.
– The lower the atmospheric pressure, the lower the
boiling point.

8. BOILING POINTS
• Halothane
• Enflurane
• Isoflurane
• Desflurane
• Sevoflurane
- 50.2 C
- 56.5 C
- 48.5 C
- 22.8 C
- 58.6 C

9. • VAPORIZER OUTPUT: refers to the
concentration of vapor at the outlet of vaporizer.
• VAPORIZERS CONCENTRATION :denotes
the concentration delivered by a vaporizer when
fresh gas containing no vapor flows through it.
– Out of system vaporizer: output = conc.
– In system vaporizer : output >conc. (expired gases
contain some agent )

10. VAPORIZERS CAPABILITY
• Refers to the maximum concentration that can be
delivered by a vaporizer at the highest setting of
the concentration dial.
• Eg: sevoflurane has a higher MAC than
isoflurane. So needs vaporizer with a higher
capability (max 8%) than isoflurane (max 5%).

11. VAPORIZERS EFFICIENCY
• Ability of a vaporizer to saturate the carrier gas
passing into the vaporizing chamber at the
temperature of the liquid.
Increased by a)Wicks
b)baffles or spiral tracks
c)longer vaporizing chamber
(inc. surface area for vaporization).

12. GAS CONCENTRATION
• TWO METHODS USED TO EXPRESS :
– partial pressure
– volumes percent
A. Partial pressure:
– The part of the total pressure due to any one gas in
the mixture is called as the partial pressure of that
gas.
– Depends only on temperature of the agent.

13. Contd….
B. Volumes percent :
– The number of units of volume of a gas in relation to
a total of 100 units of volume for the total gas
mixture.
– Partial pressure /total pressure = vol.percent

14. Partial pressure Volume percent
Relative ratio
Indirectly related
Absolute value
Patient uptake and depth of
anesthesia are directly related.
At a given partial pressure ,
anesthetic agent will have same
potency under various
barometric pressures.
Not so.

15. Heat of vaporization
• The number of calories necessary to convert 1g of liquid
(or 1ml) into a vapor.
• Liquid temperature decreases as vaporization proceeds.
• So the heat flows from the surroundings into the liquid to
compensate for the lost heat.
• IMPORTANCE :If the lost heat is not compensated ,
there will be decrease in agent delivered.

16. Specific Heat
• Is the quantity of heat required to raise the temperature of
1g of the substance by 1 C.
– IMP : The higher the specific heat ,the more heat that is
required to raise the temperature of a given substance.
– Choice of material of vaporiser should have high
specific heat as this provide a more stable temperature.
– Amount of heat that must be supplied to a liquid
anesthetic to maintain a stable temperature is known.
(heat is lost during vaporization)

17. Thermal conductivity
• Is a measure of the speed with which heat flows through a
substance.
• To construct a vaporizer,a substance with high thermal
conductivity is used.
– Eg. Copper,bronze.
• Importance: heat lost during vaporization can be rapidly
supplied if the substance has high thermal conductivity.

18. HISTORY
• First vaporizer was developed by Lucein Morris, named as
copper kettle vaporizer.
• Shu-Hsun Ngai Proposed the incorporation of
thermometer in vaporizers.

19. MORRISCOPPERKETTLE
VAPORIZER

20. COPPER KETTLE
(FOREGGER COMPANY)

21. VERNITROL VAPORIZER
(OHIO MEDICAL PRODUCTS)

22. Copper kettle and vernitrol
If vapor pressure and temperature of anesthetic
liquid is known,concentration of inhaled
anesthetic is calculated.
DISADV:
NOT TEMPERATURE COMPENSATED.

23. TECOTA VAPORIZER
(temperature compensated
trichloroethylene air)
BI METALLIC STRIP
made of brass and
nickel-steel alloy with
different coefficients of
expansions.

24. Vaporizers and standards
• ASTM anesthesia work station standard contains
the following provisions regarding vaporizers :
• 1)The effect of variations in ambient temperature
and pressure ,tilting,back pressure,and input flow
rate and gas mixture composition on vaporizer
performance must be stated in the accompanying
documents.

25. WITH OUT A BACK PRESSURE
• 2)The average delivered concentration from
the vaporizer shall not deviate from the set
value by more than ±20% or ±5 % of the
maximum setting ,which ever is greater ,
without back pressure.

26. WITH BACK PRESSURE
• 3)The average delivered concentration from the
vaporizer shall not deviate from the set value by more
than +30% or -20% or by more than +7.5% or -5% of
the maximum setting ,which ever is greater ,with
pressure fluctuations at the common gas outlet of 2Kpa
with a total gas flow of 2L/min or 5Kpa with a total gas
flow of 8L/min.

27. – A system that prevents gas from passing through the vaporizing
chamber or reservoir of one vaporizer and then through that of
another must be provided.
– The output of the vaporizer shall be less than 0.05% in the OFF
or zero position ,if the zero position is also the OFF position.
– All vaporizer control knobs must open COUNTER CLOCK
WISE.
– Either the maximum and minimum filling levels or the actual
usable volume and capacity shall be displayed.

28. IDEAL VAPOURIZER
• FIXED DESIRED CONC. (EQUAL TO CONC.
ON DIAL SETTING)
• INDEPENDENT OF TEMPERATURE ,
FLOW RATE AND CARRIER GAS
• NO EFFECT OF BACK PRESSURE
• EASY TO MAINTAIN AND CLEAN
• AGENT SPECIFIC

29. DORSCH AND DORSCH
CLASSIFICATION
• I.)METHOD OF REGULATING OUTPUT:
a) Variable by pass: ether bottle,TEC•
• b) Measured flow: copper-kettle,vernitrol.
• II.)METHOD OF VAPORIZATION :
• a)Flow over:
– 1. with wick – TEC
– 2.with out wick - goldman bottle

30. b.)Bubble through :copper kettle•
• c)flow over bubble through : ether bottle depending on position of
plunger.
• d)Injection :TEC 6 (desflurane)
III.TEMPERATURE COMPENSATED :
a)Thermo compensated:
1) By altered flow –TEC
2)By supplied heat –copper kettle
3) Both –EMO (epstein mc intosh oxford)
b)Non compensated : ether bottle.

31. •
•
•
IV) SPECIFICITY :
–Agent specific :TEC
–multi agent : Goldmanbottle.
V)RESISTANCE :
–plenum(high resistance) : TEC
–Draw over (low resistance) :goldman bottle,EMO.
VI)LOCATION :
–In circuit : (VIC) – E.M.O, Goldman
– out of circuit (VOC) -TEC.

32. Recent
• A.Concentration calibration
1.variable bypass
2.Measured flow 3.electronic
• B.Vaporization methods
1.Flow over
2.Injection
• C.Temperature compensation
1.Mechanical
2.Supplied heat
3.Computerized

33. Variable bypass vaporizer
a.)Has an inlet and outlet.
b.)Fresh gas flows through
bypass chamber and
vaporizing chamber.
c.)Concentration of anesthetic
agent delivered depends on
amount of gas flowing
through the vaporizing
chamber.

35. Contd….
• The total flow of gas arriving from the anesthesia machine
flow meters is split between variable bypass and the
vaporizing chamber containing the anesthetic agent.
• The ratio of these two flows, the Splitting ratio depends on
the anesthetic agent, temperature, and chosen vapor
concentration set to be delivered to the patient circuit.

36. Measued Flow Vaporizer
• A measured flow of oxygen is selected on a separate
flowmeter to pass to the vaporizer, from which vapor
emerges at its SVP. This flow is then diluted by an
additional measured flow of gases from flowmeters
on the anesthesia machine.

37. FACTORS AFFECTING THE
VAPORIZER OUTPUT
• A.)Flow rate.
• B.)Barometric Pressure
• C.)Temperature.
• D.)Intermittent back pressure.
• E.)Carrier gas composition.

38. Effect OF Flow rates
• At low flowrate:(<250 ml/min)
– The anesthetic agent delivered is less than the dial setting atlow
flow rates because of insufficient turbulence generated to
upwardly displace vapor molecules.
• At extremely high flow rates: (15L/min)
– the output is less than the dial setting, due to incomplete mixing
and failure to saturate the carrier gas.

39. Effect of Barometric Pressure
•Vaporizers calibrated at standard (Sea level)
atmospheric pressure
•Low boiling point, High SVP agents are more
susceptible to barometric pressure changes.

40. Low atmospheric pressure
 CONC CALIBERATED VAPORIZERS.
- Deliver same partial pressure [IMPORTANT FOR ANAES. DEPTH SO
CLINICAL EFFECT UNCHANGED].
- Small deviations in performance due to altered splitting ratio.
•
-Deliver higher concentration if measured in vol%
MEASURED FLOW VAPOURIZERS.
- Partial pressure increase and Vol% increased even more.

41. High atmospheric pressure.
• CONC. CALIBERATED VAPOURIZERS.
Increased density of gas  Increased resistance through
vaporizing chamber  Decreased vap. output (In both PP and
Vol%) At 2 ATM.
- Conc in VOL. % Is half
- Effect on PP is less
• MEASURED FLOW VAPOURIZERS.
Decreased conc in both PP and Vol %

42. • As vaporization continues, the temperature in vaporizing
chamber decreases as heat is lost during the process of
vaporization.
• So vapor pressure of anesthetic agent decreases and
output decreases.
• So to prevent this fresh gas flow rate is increased into the
vaporizing chamber by an expanding rod or a bi metallic
strip.
Effect of Temperature

43. Vapor out put decreases

44. Expanding Metal rod

45. Bi metalic strip

46. Cont…
• Wicks are placed in direct
contact with the metal wall of
the vaporizer to help replace
heat used for vaporization.
• Vaporizers are constructed
with metals having relatively
high specific heat and high
thermal conductivity to
minimize heat loss.

47. Effects of intermittent back pressure
• When assissted or controlled ventilation is used,the
positive pressure generated during inspiration is
transmitted back to the machine and vaporizers.
• Back pressure may either
• Increase vapor output-PUMPING EFFECT
• Decrease vapor output- PRESSURIZING EFFECT

48. Pumping Effect
• Concentrations delivered by vaporizers increase
during ventilation than used with free flow to
atmosphere.
• Change is more pronouced when
– less agent in vaporizing chamber
– low carrier gas flow
– pressure fluctuations are high and frequent.
– dial setting is low.

49. MECHANISM

50. INSPIRATION
Pressure in bypass and
vaporizing chambers
increase.
As bypass has smaller
volume than vaporizing
chamber more gas enters
vaporizing chamber.

51. Increased
vaporization
Extra gas entering
vaporizing
chamber collects
the anesthetic
vapour

52. EXPIRATION
When bag is
released, the
compressed gas
expands in all
directions.

53. Some of the rapidly
expanding vapor
containing
anesthetic agent
enters the inlet and
cross over into the
bypass channel .

54. This vapor in bypass
chamber adds to that
of vapor coming from
vaporizing chamber
and increases the
final anesthetic conc.
Delivered. (pumping
effect).

55. MODIFICATIONS TO MINIMIZE THE PUMPING
EFFECT
1.) long
inlet tube:
The extra gas can
not enter the bypass
channel as inlet tube
is long.

56. 2.) Increase in
the internal
resistance
of vaporizer
resists changes
due to back
pressure
ventilation.

57. 3.)Oneway
valve.
Allows the flow of
gas in one direction
only and prevents
the reverse
direction.

58. PRESSURIZING
EFFECT
Increased pressure is applied to
the vaporizer outlet.
Compress carrier gas ,so that
there will be more molecules/ml.
The no of anesthetic vapor
molecules will not increase.(as
this depends on vapor pressure of
anesthetic).
Net effect is decrease in conc of
anesthetic delivered.

59. EFFECT OF BACK PRESSURE.
PUMPING EFFECT
 Higher conc than indicated
on dial delivered.
- inc. by :
- Large pressure fluctuations
- Low dial setting
- Low flow rate
PRESSURING EFFECT
 Lower conc than indicated
on dial delivered.
- Inc by :
- Large pressure fluctuations
- Low dial setting
- High flow rate

60. Effect of Carrier Gas Composition
•
•
•
•
Vaporizer output may be affected with change of
carrier gas composition
When the carrier gas is quickly switched from
100% oxygen to 100% nitrous oxide, there is a
rapid transient decrease in vaporizer output
followed by a slow increase to a new steady-state
value
As Nitrous oxide's being more soluble than oxygen
in halogenated liquid.
So the quantity of gas leaving the vaporizing
chamber is transiently diminished until the
anesthetic liquid is totally saturated with nitrous
oxide.

61. Factors affecting steady state
• A)viscosity and density of carrier gas.
• B) solubility of carrier gas in the anesthetic liquid.
• C) flow splitting characteristics of the specific
vaporizer.
• D) concentration control dial setting.

62. Tec 6
• Electrically heated,pressurized device specially
designed for Desflurane.
• 1)HIGH VAPOR PRESSURE:
• Has vapor pressure 3 to 4 times that of others.
• So at, same flow rate, the amount of desflurane
delivered is DANGEROUSLY HIGH.

63. Contd…
• 2) LACK OF AN EXTERNAL HEAT
SOURCE:
– MAC of desflurane is high.
– So ,rate of vaporization in a vaporizer is high and
leads to excessive cooling of the vaporizer. This
causes reduced output.
– In the absence of an external heat source,the
temperature compensation is almost impossible.

64. Two independent gas
circuits.
Vapor originates in the
desflurane sump
which is electrically
heated and
thermostatically
controlled to 39C
Fixed restrictor

65. The differential pressure
transducer conveys the
pressure difference b/w
the fresh gas circuit and
the vapor circuit to the
control electronics
system, which regulates
the pressure control
valve.

66. Steady state
Differential pressure transducer
Fixed resistance

67. Increased fresh gas flow
Pushes diaphragm upwards.
Signals
Pressure
Control valve

68. Differential pressure transducer in
Neutral positionIncreasd vapor flow

69. INDIVIDUALVAPORIZERS….

70. Goldman Vaporizer
• Conc. calibrated  Flow over
(Without wicks)
No temp compensation•
• ,Agent non specific (Halothane
ether, trilene)
• In & Out of system

71. Goldman vaporizer
• Optimum functionality based Goldman Halothane Vaporizers
• Are made available in without stand finish
• Vaporizers comprises vaporizing chamber including glass
bowl/bottle that contains liquid anesthetic as well as a tap that
controls proportion of gas flowing through it
• Drawover type finish
• Designed for limiting maximum concentration of Halothane
vapour to 3% (this is achieved irrespective of total gas flow
through unit)
• Adjustment made using ratchet type control valve
• Glass jar screwed to body with quick detachment possibilities
for easy filling
• Vaporizer also suitable for use with Trichloroethylene in low
concentration

72. Boyles Bottle
• Variable bypass (Conc
calibrated)
Flow over wicks•
•
•
Out of system
No temp compensation
• Muliple agent (Ether,
trilene, Halothane)

73. Boyle’s Bottle
•The Boyle bottle ether vaporiser has two controls. The lever on the
upstream side of the vaporiser, permits a proportion of the gas from
the flowmeters to be ducted through the vaporiser or to bypass it.
•The control is uncalibrated but has extreme markings of 'OFF' and
'ON' and permits continuous proportional adjustment.
• The rod at the top of the vaporiser, known as the 'plunger', controls
the extent to which the incoming gas is delivered to the liquid ether.
• Within the vaporiser bottle it terminates in a cap that advances over
the up-turned u-shaped gas inlet tube.

74. Boyle’s Bottle
•The plunger, initially fully raised, is progressively lowered. Gas is
directed to pass more closely over the liquid ether surface and is
ultimately bubbled through the liquid ether. This is the maximum
setting possible.
• The rate of vaporisation causes rapid cooling so that the vapour
concentration begins to diminish.
•The cooling can be delayed by filling the accessory water bath with
water at room temperature. Without the water bath, the bottle will
chill until frost forms on the glass to the level of the liquid ether.
•The 'U' shaped inlet tube within the vaporiser and the cap of the
plunger are made from unplated copper. This is considered to
protect the ether from degradation.

75. Boyle’s Bottle
• Boyle's original ether bottle did not include the plunger or the
water bath. They were added during successive enhancements of the
basic design.

76. E.M.O. (1952)
(EPSTEIN MACINTOSH OXFORD VAPORIZER)
Draw over inhaler
Variable bypass
Flow over without wicks
•
•
•
• Temp compensation by
supplied heat & flow
alteration
• Agent specific

77. E.M.O.
• Round, barrel style object with three small rubber feet and a
moulded handle over the top.
• Consists of a vaporising chamber, wick, ether level indicator,
temperature compensating value, air bypass chamber and mixing
chamber.
•It was essentially a refinement of their earlier Oxford vaporizer and
designed specifically to deliver ether in known concentrations,
irrespective of the temperature of the ether.
•Accurate output of 0-20% ether.
•Tempurature compensated by ether/freon filled metal bellows.

78. E.M.O.
• Temperature is stabilised by the water jacket surrounding
vaporizing chamber.
• TCU i.e. temperature compensating unit consists of a rod with
1. Black band
2. Red band
3. Metal top
• At 20-25 deg , metal top and black band should show
• Temp above 32 deg , red band should show
• If only metal band can be seen at 20-25 deg then TCU is faulty.

79. OXFORDMINIATUREVAPOURIZER
• Draw over and plenum
• Thermo-stabilized
• Concentration calibrated
• Agent non –specific.
• (Halothane, trilene,
methoxyflurane)

80. O.M.V.
•Originally produced to be used together with EMO in order to
speed up the induction of anaesthesia.
•Capacity – 50ml
•Facility of small heat sink/reservoir containing 30% glycol in
water to provide large thermal mass.
•Output is affected by ambient temperature changes.
•Max output for halothane is 2-4%.
•Output can be increased by arranging two units in series and is
required for induction with sevoflurane.

81. TEC 2
•Agent-specific for Halothane,
• Variable bypass,
• Flow over with wicks,
• Low resistance,
•Temperature compensated
with bimetallic strip in vapour
path, non-tippable,
•No interlocks,
•Non-keyed filler.
•Volume 750ml
•Calibrated to 0 to 4 %

82. Tec 2
• Construction:
Vaporizing chamber- round with concentric wicks.
Bimetallic strip- outlet of chamber.
Dial in front.
• Gas flows:
Controlled by spindle- rightward movement.
OFF position-flow only through bypass chamber.
ON position-more gas through vaporizing chamber.

83. Tec 2
• In a bimetallic strip, two metals with very different coefficients of
thermal expansion are fixed together.
• When the temp. of the vaporizing chamber drops, the bimetallic
strip bends and moves away. This reduces the resistance to flow and
thus more flow occurs into the vaporizing chamber

84. • At low flow , at higher conc settings , it was made to deliver
purposefully higher output than indicated to accelerate
induction however at low concentration settings its output was
much less
• DISADV :
• Not accurate below 4l/min.
• Bimetallic strip getting stuck due to thymol
deposition. So a stabilising agent in 0.01%
concentration added to halothane.
• Nitrous oxide affects out put.
• Subject to pressurizing and pumping effect.
• Filling tap is at side – chance of over fill.

85. TEC3
•Conc-calibrated, flow over with
wick, automatic thermo-
compensation.
•Bimetallic temp-sensitive element that
is located concentrically within bypass
chamber.
•Volume decreased to 250ml
•Vaporising chamber at high
pressure(overcomes the resistance to
flow of relatively dense saturated
vapor even at low flow rates.)

86. Contd…
Advover tec 2 :
• Accurate with lower dial settings. Nitrous oxide has little effect
on output.
• Between off and 0.5% ,dial setting, output is less affected by
fresh gas flow.
• Sudden increase or decrease in FGF ,back pressure,O2 flush has
negligible effect on vapour output.
• Filling and draining is at bottom- so over-filling is avoided.

87. • DIS ADV:
• small amounts of leaks in bypass in OFF
position.
• Can be rotated beyond off position, resulting in
delivery of vapour.
• Tipping upto 90 degrees has no affect.But beyond 90
degrees causes increase in output.

88. Tec4
• The release button to the left
must be depressed before the
vaporizer can be turned on.
•Designed for out of circuit
• Safety interlock system for
ensuring a,single vaporiser
useonly at anytime.
• Internal baffle system to
prevent contamination ofthe
bypasschamber on tilting.
• Enflurane(0-7%),Halothane(0-
5%),Isoflurane(0-5%)dial
settings

89. Tec 4
• Parts –
• On top- Control Dial that is turn clockwise to increase the
concentration.
•A release button on the left of concentration dial must b depressed
before the vaporizer is turned on.
• Locking lever-connected to control knob.
•When the vaporizer is turned on, 2 plungers within the vaporizers
operate to open the valve into the Fresh gas stream. Also prevent the
use of any adjacent vaporizers,
•2 Filling mechanisms- Screw cap and Keyed Filling system

90. Tec 4
Gas flows –
•OFF Position - incoming gas flows from inlet and into one channel
across the top of the vaporizer , without coming in contact with
vaporizing chamber or temperature compensating device and leave
through the outflow
•ON Position- •incoming gas split into 2 streams by a rotary valve
attached to concentration dial. • 1 stream goes to VC and that enters
one of the two chambers which surrounds the bypass chamber. •After
passing it is directed over 2 concentric wicks that enclose a copper
helix which converts this space into long spiral outlet channel.

91. Tec 4
• Wicks assure maximum contact between gas and agent.
• This vapor laden gas leaves via the second chamber surrounding
bypass chamber to outlet.
• The remaining Fresh gas flows to the bypass chamber which
contains temperature sensitive element.
• No spillage after tilting or inversion.

92. Tec 4
•Fluctuation back pressure can increase the concentration.
•Greater effects seen atlow flow rates, low dial setting, large and
frequent pressure fluctuations.
• N2O- decreases output slightly.
•Vaporizer is filled and used in upright position- deviation do not
affect the output or safety.

93. Tec 5

94. Tec 5
• Variable Bypass
• Flow over wick
• Out of System
• Temperature Compensated by automatic flow alteration
• Concentration Calibrated
• Agent Specific

95. Tec 5
•The control dial is at the top, the dial must be pushed in before the
vaporizer can be turned on.
• At the rear is a locking lever that is connected to the control dial so
that the vaporizer cannot be turned on until it is locked on the
manifold.
•At the bottom right front is a sight glass that shows the liquid agent
level in the vaporizing chamber.
•When the dial is turned past zero, inflowing gas is split into two
streams by the rotary valve.
•One stream is directed to the vaporizing chamber, the other through
the bypass.

96. Tec 5
•The internal baffle system is designed to keep liquid from reaching
the outlet if the vaporizer is tipped or inverted.
•When the concentration dial is in the zero position, all of the gas
from the flowmeters bypasses the vaporizer through the select a tec
bar.
•Gas flowing through the bypass flows down one side of the
vaporizer and past the thermostat , which is bimetallic strip in the
base.
•As the temperature in the vaporizer decreases , the thermostat
permits less gas flow through the bypass so that more gas passes
through the vaporizing chamber

97. Tec 5
•From the thermostat, gas flows up the other side of the vaporizer
and near the outlet joins the gas that has passed through the
vaporizing chamber.
• Gas flowing to the vaporizing chamber first passes through the
central part of the rotary valve after which it is directed through a
helical channel then past a spiral wick that is in contact with the
wick skirt, which dips into the liquid agent.
•Benefits of TEC 5: Helical IPPV assemble to minimize effects of
positive pressure ventilation.
•Volatile Agent capacity increased from 125ml to 300ml One
Handed Dial and more obvious off position Internal Baffle system
designed to prevent liquid from reaching the outlet if vaporizer is
tipped or inverted.

98. Tec 5
•Tec 5 vaporizers are available with either of two filling devices:
1. Keyed system
2. Funnel fill
•Funnel Fill System
•Vaporizer Components The vaporizer filling components include a
funnel and cap.
•When the cap is removed, liquid can be poured into the vaporizing
chamber through the funnel.
•When the full level is reached, liquid will accumulate in the funnel,
and no more liquid will enter the vaporizer.
•A funnel-fill vaporizer can be converted to an agent-specific keyed
filling system by the addition of an adaptor that screws into the

99. Tec 5
Bottle Component :
•A color-coded adaptor is available to aid the filling process. At one
end is a connector with a screw thread to match the thread on the
bottle and a skirt that extends beyond the screw threads.
• It has slots that match the projections on the bottle collar.
•The adaptor for a different agent than the adaptor is intended for will
not screw on either because of different threads or bottle opening size
or because the projections will not line up with the slots on the
adaptor

100. Tec 5
Filling Procedure
•The filler cap is removed by turning it counterclockwise.
•Agent is poured into the filling port until the level reaches the full
mark.
•The level may fall slightly as the wicks absorb the agent.
•The filler cap is then securely replaced.
Draining Procedure
•To drain the vaporizer, a container is placed under the drain.
• Removing the filling cap will usually speed drainage.
• The mechanism for opening the drain varies with the vaporizer.
•After draining is complete, the drain plug should be replaced and
tightened to minimize leaks.

101. Tec 5
Keyed Filling System
•The keyed filling system has been used by many manufacturers for
a variety of anaesthetic agent Vaporizer Component The vaporizer
filler receptacle (filler socket or block, vaporizer filler unit) permits
only the intended bottle adaptor to be inserted.
•The receptacle should be sealed when the bottle adaptor is not
inserted. A metal filler block (plug) may be used.
•There may be a single port for both filling and draining or two
ports, the upper one for filling and the lower one for draining .

102. Tec 5
• Accuracy is maximum at a flow of 5lit/min with a dial setting less
than 3%.
•Greatest accuracy is between 15 and 35 deg (less than 15 deg output
will be less) and more than 35 deg output will be high.
• Prone to Increase in output due to pumping effect
•Carrier Gas Composition effects the output
•At low flows output is less if air or nitrous oxide is used as
compared to when oxygen is used

103. Problems with desflurane
Desflurane is much more volatile than all the other inhalationals.
▪ Its boiling point is low -- only 22.80 C, so most of it gets
evaporated at normal room temperatures
▪ Vapor pressure of desflurane at 200 C is 664 mm Hg.
▪ While that of Enflurane, isoflurane, halothane are 172, 240, 244
mm Hg. respectively
▪ At 1 atmosphere and 200 C , 100mL/min flow passing through
vaporizing chamber would carry
▪ 735 mL/min. of desflurane versus 29, 46 and 47 mL/min of
enflurane, Isoflurane and halothane respectively.
▪ Under these conditions to produce 1% of desflurane,
▪ we need 73 L/min Fresh Gas Flow as compared to 5 L/min for
other anesthetics, to pass through vaporizer

104. Tec 6
• Specifically designed to deliver Desflurane
• Described as a gas/vapor blender than as a vaporizer.
• It is heated electrically to 350 C
• Pressurized Device with a pressure of 1550 mmHg (2 atm)
• Electronic monitors of vaporizer function
• FGF does not enter vaporization chamber, instead Desflurane
vapor enters the path of FGF
• Percentage control dial regulates flow of Desflurane into FGF
• Dial calibration is from 1% to 18%
• Provided with back up 9 volt battery

105. Tec 6
• The pressure in the vapor circuit is electronically regulated to
equal the pressure in the fresh gas circuit.
• At a constant fresh gas flow rate, the operator regulates vapor
flow by use of a conventional concentration control dial.
•When the fresh gas flow rate increases, the working pressure
increases proportionally.
• At a specific dial setting, at different fresh gas flow rates,
vaporizer output is constant because the amount of flow through
each circuit is proportional.

106. Advantages
• Comparable accuracy to variable bypass Tec 5 vaporizers; +/- 15% of
dialled setting.
• Unaffected by ambient temperature because the desflurane is
heated.
• Automatically compensates for variation in FGF.
• Has visual and audible alarms to alert the anaesthetist that the
vaporizer is almost empty or that there is no output.

107. Disadvantages
• Requires an electrical power supply.
• Requires time to warm up before it is operational Safety
• As with other Tec vaporizers, it is very difficult to fill the Tec 6
vaporizer with an anaesthetic other than desflurane due to the key
system for filling. There is also a colour coding system that helps
prevent filling of vaporizers with the wrong anaesthetic.
• The Tec 6 design prevents desflurane liquid spilling into the FGF if
the vaporizer is tilted or inverted.

108. There are two mechanisms that govern the release of
desflurane vapour into the FGF.
1. The first is the dial that is located on top of the vaporizer that
is set to a desired concentration by the anaesthetist.
2. The second is a valve that maintains the set concentration, in
response to changes in the FGF (if the FGF increases then the
rate of desflurane release must also increase to maintain a
constant concentration). This is achieved by a differential
pressure transducer which compares the pressure in the
desflurane circuit with that in the FGF circuit. When the FGF is
increased, its pressure also increases and this is detected by the
transducer. A microprocessor then opens the valve enough to
increase the amount of desflurane that is injected. The opposite
occurs when the FGF is reduced.

109. TEC7:
an improved version of the TEC
5 was introduced in July
2002 by Datex-Ohmeda
with minor modifications
1. "Easy-fil" filler mechanism
2. New ergonomics and
design
3. Planned factory service
free
4. Improved sight glass
design

110. ALADIN
VAPORIZER
2 parts.
a)Electronic control system
in anesthesia machine
b)A portable cassette
containing agent.
The flow at the out let is
controlled by the CENTRAL
PROCESSING UNIT in the
anesthesia machine.

111. •The Aladin Cassette can be handled or
stored in
any position.
Automatic record keeping and gas
usage calculation
•Electronic control of desired agent
concentration .
.Provides agent setting data for
automatic record
Keeping and fresh gas flow data.
•Gas usage data provides a unique tool
for low flow

112. DRAGER 19.1
similar to tec 4,5 vaporizers.
The interlock on Dräger machines
continues to function if any vaporizers
are removed.
There is no outlet check valve- the
tortuous inlet arrangement protects
from the pumping effect.
No anti-spill mechanism.
Should not be tipped more than 45.

113. Drager 19.1

114. Drager 2000 :
•Is one of two tippable
vaporizers (ADUcassettes are
the other).
•The dial must first be rotated
to a "T" setting ("transport" or
"tip") which is beyond zero
(clockwise).
•Tortous in let protects against
pumping effect.

116. Filling devices
• Funnel fill system
• Keyed fill system
• Quik- fil system
• Easy-fil system

117. FUNNELFILL
Vaporizers may be filled
by a conventional funnel-
fill mechanism, in which
the liquid anesthetic is
simply poured into a
funnel in the vaporizer.
Complication is filling
with wrong agent.

118. KEYEDFILL
In this system, an agent-specific
filler tube is used, one end of
which slots into a fitting on the
vaporizer, and the other end
slots into a collar on the bottle
of anesthetic. The fitting on the
vaporizer and the collar on the
bottle are specific to each
agent.

119. QUIKFIL:
The bottle has a
permanently attached,
agent-specific filling
device that has three
ridges that fit into slots
in the filler.

120. EASY FIL :
A color coded bottle
adaptor is attatched to
bottle and then fitted into
the vaporizer.
A drain plug is there for
draining vaporizer.

121. Hazards of a vaporizer
• a)In correct agent
• b)Tipping
• c)over filling
• d)reversal of flow
• e)leaks

122. a)In correct agent: minimized by agent specific filling
devices, color coding, agent monitors.

123. Contd…
b)TIPPING: lead to delivery of very high
concentrations of vapor. Prevented by
– 1.Mounting vaporizers on manifold.
– 2.draining vaporizer before being moved.
c) OVER FILLING :
– Liquid agent enter the fresh gas line, leading to high
concentrations.
– Prevented by low level filling port, indicator glass.

124. D )REVERSAL OF FLOW :
output is increased.prevented
by indicator arrows.
E) LEAKS : lead to
wastage of agent, OT
pollution,delivery of wrong
concentrations.
prevented by
NEGATIVE PRESSURE
CHECK TEST

125. Thank you