VAPORIZER Lakshmanraj

VAPORIZER

Dr.K.M.LAKSHMANARAJAN . MD.

REFERENCES

• DORSCH AND DORSCH• WARD’S• MILLER

• WHAT IS VAPOR ? • Vapor is the gaseous phase of a substance which is

normally a liquid at room temp. and atm. pressure. Eg. water vapor is the vapor form of water

• Gas is substance which exists only in the gaseous state at room temp. and amt. pressure.

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WHAT IS A VAPORIZER ?

• A vaporizer is an instrument designed to facilitate the change of a liquid anaesthetic agent into a vapor

And

Add a controlled amount of this vapor to the FGF• The SVP of most inhalation agents is MUCH more that

is required to produce anesthesia i.e. 32% vs 0.75 or 243 mm Hg vs 5.7 mm Hg for halothane

• Need to dilute this vapor with the carrier gas and deliver a controlled amount of this vapor to the patient

DISCUSSION

• EVALUATION OF VAPORIZER• PHYSICS APPLIED TO VAPORIZER• HOW IT WORKS?• CLASSIFICATION• INDIVIDUAL VAPORIZER• HAZARDS & SAFETY FEATURES • IDEAL VAPORIZER

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EVOLUTION….EVOLUTION….

Wilson and Pinson's Ether

"Bomb

Schimmelbusch's Inhaler

Foregger Model of Morris' Copper Kettle

Vaporizer

EMO VAPORIZER

MORTON INHALER

http://www.general-anaesthesia.com/images/oliver-holmes.html

FLAGG’S CAN

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EVOLUTION OF VAPORIZERS

• MORTONS ETHER INHALER

1846, OCT 16

SNOW – MARCH 1847

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CLOVER PORTABLE REGULATING ETHER INHALER 1877

VERNON HARCOURT CHLOROFORM INHALER 1903

OMBREDANNE ETHER INHALER 1908

SOMNOFORM INHALER 1908

• Mixture of ethyl chloride, methyl chloride & ethyl bromide

Free Template from www.brainybetty.com 15

OPEN DROP MASK

OGSTON INHALER

EPSTEIN MACINTOSH OXFORD VAPORIZER 1952 (EMO)

GOLDMAN VAPORIZER

ROWBOTHOM VAPORIZER

• Modification of Goldman vaporizer

POCKET TRILENE INHALER

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PHYSICSAPPLIED TO VAPORIZER

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WHAT IS CRITICAL TEMPERATURE ?

• For any substance there is a max. temp. at which it can be compressed so as to convert it from a gas to a liquid. This is known as the critical temp. and above this temp. no amount of compression will liquefy it.

• Under this condition the substance is a gas. • Below that critical temp it is a vapor.

• A gas that is currently below its critical

temperature is called a “vapour”.• If compressed with enough pressure, it will condense into a

liquid.

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Critical temperature of Critical temperature of

• Oxygen –118Oxygen –11800CC

• Nitrogen –147Nitrogen –147ooCC

• Air –141Air –141ooC C

• Carbon dioxide 31Carbon dioxide 31ooCC

• Nitrous oxide 36.4Nitrous oxide 36.4ooCC

• Entonox - 5 to -7 (psuedocrit-temp)Entonox - 5 to -7 (psuedocrit-temp)

ISOFLURANE ON VENUS

• The critical temperature of Isoflurane is about 200 C

• The temperature on the planet Venus is about 500 C

So if you lived on Venus, Isoflurane would exist as a gas.

• On earth, since The temperature where you live is hopefully below the critical temperature of Isoflurane, it exists as a vapour / liquid.

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VP & SVP

• Vapor exerts a pressure on its surroundings – Vapor pressure .

• Vapor pressure depends only on the temp. and liquid.

• Vapor pressure of an agent determines how much of vapor will be formed from 1 ml of the liquid.

• Since different anaesthetic agents have different vapor pressures the need separate vaporizers.

• For a particular liquid at a particular temp. there occurs an equilibrium at which the number of molecules leaving the liquid equals the number reentering

• It is the maximum VP at a particular temp. Increases rapidly as boiling point approaches.

HOW DO YOU DEFINE BOILING POINT…?HOW DO YOU DEFINE BOILING POINT…?

-Is the temperature at which the vapor pressure reaches the atmp - decrease the atmp – dec the BP -increase the atmp – incre the BP

IF THE B.P OF ETHER IS 36.5 C , WILL IT BE BOILING IF THE B.P OF ETHER IS 36.5 C , WILL IT BE BOILING ALWAYS IN THE ROOM TEMP IN THE SUMMER IN ALWAYS IN THE ROOM TEMP IN THE SUMMER IN MADURAI WHEN THE TEMP IS 40 C…?MADURAI WHEN THE TEMP IS 40 C…?

• SVP MAY BE > ATMP SVP MAY BE > ATMP • ATMP MAY BE > SVP ---- its not BP ATMP MAY BE > SVP ---- its not BP •To get boiling point SVP to reach ATMP To get boiling point SVP to reach ATMP

BOILING POINT ?

S.NOS.NO LIQUID ANESTHETICLIQUID ANESTHETIC B.P in CB.P in C

11 ETHYL CHLORIDEETHYL CHLORIDE 12.412.4

22 DESFLURANEDESFLURANE 22.822.8

33 ISOFLURANEISOFLURANE 48.548.5

44 HALTHANEHALTHANE 50.250.2

55 ENFLURANEENFLURANE 56.556.5

77 SEVOFLURANESEVOFLURANE 58.658.6

88 ETHER ETHER 34.634.6

99 METHOXY FLURANEMETHOXY FLURANE 105105

BOILING POINT BOILING POINT

GAS CONCENTRATION:GAS CONCENTRATION:

Partial pressure:Partial pressure:

•Molecular agitationMolecular agitation

•Bombardment on the walls of containerBombardment on the walls of container

•Creation of a pressureCreation of a pressure

•Dalton’s law of partial pressure: Dalton’s law of partial pressure: total pressure of the mixture is the sum of thetotal pressure of the mixture is the sum of thepartial pressures of the constituent gasespartial pressures of the constituent gases

•Volume percent: partial pressure/ total pressure x 100Volume percent: partial pressure/ total pressure x 100

HEAT of VAPORIZATION

• In a liquid, molecules are in a state of continuous motion because of mutual attraction by Van-der Waal’s forces.

• Some molecules may develop velocities sufficient to escape from these forces and may enter the vapour phase.

• The amount of heat required to convert a unit mass of liquid into a vapour without a change in temperature of the liquid is termed

the heat of vaporization.

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HEAT OF VAPORISATION:HEAT OF VAPORISATION:

•No of calories necessary to convert 1 G of liquid into vapourNo of calories necessary to convert 1 G of liquid into vapour

•Effect of heat loss on continuous vaporisationEffect of heat loss on continuous vaporisation

•Gradient of temp. between liquid and surroundingGradient of temp. between liquid and surrounding

•Ways of Supplied heatWays of Supplied heat

SPECIFIC HEAT CAPACITYSPECIFIC HEAT CAPACITY

Quantitiy of heat required to raise the temp of 1 G of the Substance by 1 C

Material used to construct the vaporiser should have High sp.heat capacity

THERMAL CONDUCTIVITY:THERMAL CONDUCTIVITY:

Measure of the speed with which heat flows throughMeasure of the speed with which heat flows througha substancea substanceCu > Al > brass > steel >> glass

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Agent

Boiling Point (°C,

760 mm Hg)

Vapor Pressure

(torr, 20°C)

Density of Liquid (g/mL)

Heat of Vaporization Specific Heat of Liquid

MACa in O2 (%)cal/g cal/mL cal/mL cal/g

Halothane

50.2 243 1.86 (20°C)

35 (20°C) 65 (20°C) 0.35 0.19 0.75

Enflurane 56.5 175 1.517 (25°C)

42 (25°C) 63 (25°C) 1.68

Isoflurane 48.5 238 1.496 (25°C)

41 (25°C) 62 (25°C) 1.15

Desflurane

22.8 669 1.45 (20°C)

6.4

Sevoflurane

58.6 157 2.0

VOLATILE AGENTSBoiling point

SVP at 20ºc MAC BG coefficient

Desflurane 22.8º c 669 mmhg 6.4 0.45

Ether 34.6º c 425 mmhg 1.92

Isoflurane 48.5º c 175 mmhg 1.15 1.4

Halothane 50.2º c 243 mmhg 0.75 2.5

Enflurane 56.5º c 175 mmhg 1.68 1.8

Sevoflurane 58.5º c 157 mmhg 2.0 0.65

Methoxyflurane 105 º c 20 mmhg 0.2 12-15

Nitrous oxide 21.2º c 4000 mmhg 104 0.47

Xenon -108.1ºc 60-70 0.115

HOW IT WORKS ?

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VAPORIZATION

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VAPORIZATION

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VAPORIZATION AT HIGH FLOW

• If one uses a high fresh gas flow, the vaporisation process can't keep up with so much gas arriving into the vaporisation chamber.

• The result is that, relative to the high flow of fresh gas flow, the amount of anaesthetic vaporised is inadequate.

• So,, the vaporiser delivers less anaesthetic concentration than is set on the dial

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VAPORIZER IN HIGH FLOW

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VAPORIZATION AT HIGH FLOW

• The solution employed by modern vaporisers to solve this problem is to increase the surface area of contact between the fresh gas and anesthetic agent.

• The output concentration remains accurate to the setting on the dial over a wide range of flows.

• One method that vaporisers use to increase the efficiency of vaporisation is to dip wicks into the anaesthetic agent

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WICKS

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BUBBLE THROUGH

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BUBBLE THROUGH

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SPECIFIC HEAT

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This property is used in the design of temperature compensating valves in vaporizers.

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THERMAL STRIP

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Another method uses a "bi metallic" strip. Different metals expand and contract to differing extents when exposed to temperature changes

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EFFECT OF TEMPERATURE ON THE EFFECT OF TEMPERATURE ON THE PERFORMANCE OF VAPORISERSPERFORMANCE OF VAPORISERS

•As liquid is vaporised, energy is lost in the form of As liquid is vaporised, energy is lost in the form of heatheat

•As the temp. decreases, so does the vapour pressureAs the temp. decreases, so does the vapour pressure

• vaporisation decreases, so does the vaporiser outputvaporisation decreases, so does the vaporiser output

Effect of heat loss on the performance of Effect of heat loss on the performance of Boyle’s bottle:Boyle’s bottle:

METHODS OFMETHODS OF TEMPERATURE COMPENSATION:TEMPERATURE COMPENSATION:

1.1. Supplied heatSupplied heatLarge mass of copper – high specific heat and Large mass of copper – high specific heat and thermal conductivitythermal conductivitywater jacketwater jacketelectric heaterelectric heater

2. Flow compensation2. Flow compensationIncrease the % of carrier gas flow that is directedIncrease the % of carrier gas flow that is directedthrough the vaporizing chamberthrough the vaporizing chamber

EFFECT OF EFFECT OF INTERMITTENT BACK PRESSURE:INTERMITTENT BACK PRESSURE:

Positive pressure from breathing system, O2 flushPositive pressure from breathing system, O2 flush

1.PUMPING EFFECT1.PUMPING EFFECT

2. PRESSURISING EFFECT2. PRESSURISING EFFECT

PUMPING EFFECT:PUMPING EFFECT:

Increased pressure fluctuation - increased gas flow Increased pressure fluctuation - increased gas flow into vaporising chamber – picking up more vapour – into vaporising chamber – picking up more vapour – which enters into the bypass chamber – diluent which enters into the bypass chamber – diluent containing vapour – increased vaporiser outputcontaining vapour – increased vaporiser output

Pumping effect

• Common in plenum ( high resistant vaporizers)• Seen in low flow anesthesia, low dial settings, low

level of liquid agent• Seen in when high RR used, high PIP, rapid drops

in airway pressure during expiration • When use O2 flush also ( during intraop)

Pumping effect (Think traffic signal, starting from signal )

During IPPV – gas flow to pt & to back bar also

Pressure rises in the back bar

Pressure transmitted to bypass channel (only FGF coming ) & to vaporizer chamber

Vapor molecules compressed inside the vapor chamber

Compressed FGF again will diverted more into vaporizer

Now SVP raised

More molecules of concentrated vapor produced

On expiration – pressure drops at common gas outlet

High concentrated vapor than the dial setting delivered to the pt

Pumping effect

PUMPING EFFECT:PUMPING EFFECT:

Modifications to minimise the pumping effect:Modifications to minimise the pumping effect:

1. Increasing the size of bypass chamber

2. Decreasing the size of the vaporising chamber

3. Long inlet tube

4. Avoiding wicks in the inlet area

5. Increase resistance to gas flow through vaporiser

6. Unidirectional / pressurising valve at the outlet of the vaporiser

PRESSURISING EFFECT:PRESSURISING EFFECT:

Will vaporisation increase as the pressure in the vaporisingchamber increase?

SVP depends on temperature , not on pressure

This effect leads to a decrease in the vaporiser output

Pressurizing effect• According to the second concept

• Common in high flow anesthesia

• Common in VIC vaporizer• SVP of vapor not increased• Less common effect and less danger than

pumping effect

Ippv – back flow/pressure transmitted back to vaporizer / bypass

Vaporized molecules are compressed without altering SVP

Same no molecules but diluted (density reduced)

Vapor concentration decreased & delivered on expiration

Pressurizing effect

PRESSURISING EFFECT:PRESSURISING EFFECT:

Which effect is important…?Which effect is important…?

•Pumping effect is more dangerous…

•Pressurising effect occurs in high gas flows

•Pumping effect in low flows..

EFFECT OF ALTERED BAROMETRIC EFFECT OF ALTERED BAROMETRIC PRESSURE PRESSURE ON THE ON THE PERFORMANCE OF VAPORISERS:PERFORMANCE OF VAPORISERS:

•Vaporisers in high altitude and hyperbaric chambers

•Vaporiser output concentration differs

•Partial pressure remains the same, so does depth of anesthesia

C’ = C x P/ P’

PLACING THE VAPORISER PLACING THE VAPORISER IN THE BREATHING CIRCUITIN THE BREATHING CIRCUIT

1.1. VAPORISER OUTSIDE THE CIRCLE ( VOC )VAPORISER OUTSIDE THE CIRCLE ( VOC )

2.2. VAPORISER INSIDE THE CIRCLE ( VIC )VAPORISER INSIDE THE CIRCLE ( VIC )

VOCVOC

IN THE BACK BAR….

•Between the flow meter and common gas outletBetween the flow meter and common gas outlet

•Or between common gas outlet and breathing systemOr between common gas outlet and breathing system

•Vaporisers in a row..Vaporisers in a row..

•Selectatec mechanismSelectatec mechanism

•Difficult to equalise the vaporiser concentration withDifficult to equalise the vaporiser concentration with alveolar concentrationalveolar concentration

VOC – VAPORISER IN A ROW IN THE BACK BARVOC – VAPORISER IN A ROW IN THE BACK BAR

Two consideratons:Two consideratons:

•Parallel / serials Parallel / serials •Cross contamination should be minimumCross contamination should be minimum•If it occurs, it should be least dangerousIf it occurs, it should be least dangerous

With agents equal potency the agent with the lower With agents equal potency the agent with the lower vapor pressurevapor pressureshould be upstream…should be upstream…

With agents of equal vapour pressure, the less With agents of equal vapour pressure, the less potent should be upstreampotent should be upstream

Explosive agents, trilene should be downstream..Explosive agents, trilene should be downstream..

VAPORIZER ARRANGEMENT

• In the order of SVP and potency( less SVP , less potent –first)

• Thymol added vaporizer – in the downstream

ORDER OF VAPORIZERS

• Less potent - upstream• More potent - downstream• If equipotent

Low VP - upstreamHigh VP - downstream

If explosive - downstreamTrilene - downstreamEasy to clean - downstream

UP STREAM → → → DOWNSTREAM

SEVOFLURANE

ENFLURANE ISOFLURANE

HALOTHANE

DESFLURANE

VP- 157 175 238 243 669

VAPORISERS IN A VAPORISERS IN A ROW…ROW…

VAPORISER INSIDE THE CIRCLE:VAPORISER INSIDE THE CIRCLE:

Low resistance vaporiser incorporated in the circle systemLow resistance vaporiser incorporated in the circle system•Economical

•Faster induction

•Vaporiser output and concentration are not same

•Easy to achieve alveolar concentration similar to vaporiser concentration

•Dangerous concentration may build up•2 positions:

Expiratory side, Inspiratory limb

VIC - IN THE EXPIRATORY LIMB:VIC - IN THE EXPIRATORY LIMB:

•SafeSafe•Moisture condensationMoisture condensation•Wastage through relief valveWastage through relief valve

VIC - IN THE INSPIRATORY LIMB:VIC - IN THE INSPIRATORY LIMB:

•Faster inductionFaster induction•Danger of liquid anesthetic aspirationDanger of liquid anesthetic aspiration

VAPORIZER

• Vapour output depends on

Temperature of liquid

Volatility

Surface area of liquid

FGF rate

Ippv

Carrier gas composition

Barometric temperature ( eg – high altitude)

FACTORS AFFECTING VAPORIZER OUTPUT

• 1. FLOW THROUGH THE VAPORIZING CHAMBER: Varying the proportion of gas passing through the vaporizing chamber and bypass chamber

• 2. SURFACE AREA OF THE LIQUID GAS INTERFACE: Greater the surface area, more will be the vaporization.

• Bubble through > flow over

• 3. TEMPERATURE: as temperature increase, output increase

• 4. TIME: Output concentration tend to fall over time

• 5. GAS FLOW RATE: (A) At high flowrates, the gas leaving vaporization chamber is less saturated

(B) Alters the total flow that passes through the vaporization chamber

• 6. CARRIER GAS COMPOSITION:

(a) Changes in viscosity & density may affect the proportion of the total flow passing through the vaporization chamber

(b) N2O dissolves in the flow, thus altering the effective volume passing through the vaporization chamber

• 7. BOILING POINT: Higher the boiling point, less will be the vapor output

• 8. AMBIENT PRESSURE:

- SVP is solely a function of temp. so if ambient pressure is reduced, the constant SVP becomes a greater proportion of the total pressure

-> output increases.

- Agents with low boiling points are more susceptible to the influence of ambient pressure

EFFECT OF LOW ATMOSPHERIC PRESSURE

CONCENTRATION CALIBRATED • High resistance pathway through the vaporizing

chamber offers less resistance, under hypobaric conditions and so a slight increase in vapor output occurs.

• Deliver higher conc. if measured in vol. % but deliver same PP so clinicall effect unchanged

CP =CP or C=CP/P At 0.5 atm. C=Cx1/.5=2%

EFFECT OF LOW ATMOSPHERIC PRESSURE

MEASURED FLOW• Here the delivered partial pressure & volume

percent increases.• Amount of increase depends on the barometric

pressure & the vapor pressure of the agent.• Closer the vapor pressure is to barometric

pressure, greater the effect.

CONCENTRATION CALIBRATED• ATM PRESSURE INCREASES -> Density of gas

CHANGES -> More resistance to flow of gas through the vaporizing chamber

-> Decreased vapor O/P (Partial Pressure & Volume Percent)

Effect on partial pressure is less dramatic

EFFECT OF HIGH ATMOSPHERIC PRESSURE

MEASURED FLOW

• Lower concentration in terms of PP/Volume percent

EFFECT OF HIGH ATMOSPHERIC PRESSURE

1988 ASTM MACHINE STANDARDS FOR VAPORIZERS

1. The effects 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.

2. The average delivered concentration from the vaporizer shall not deviated from the set value by more than ± 20% or ± 5% of the maximum setting whichever is greater without back pressure.

3. The average delivered concentration from the vaporizer shall not deviate from the set value by more that + 30% or – 20% or by more than + 7.5% or – 5% of the max. setting whichever is greater, with pressure fluctuations at the common gas outlet of 2 kPa with a total gas flow of 2 L/minute or 5 kPa with a total gas flow of 8 L/minute

4. A system that prevents gas from passing through the vaporizing chamber or reservoir of one vaporizer and the through that of another must be provided

5. 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.

6. All vaporizer control knobs must open counterclockwise

7. Either the max. and min. filling levels or the actual usable volume and capacity shall be displayed

8. The vaporizer must be designed so that it cannot be overfilled when in the normal operating position.

9. Vaporizer unsuitable for use in the breathing system must have noninterchangeable proprietary or 23 mm fittings. Conical fittings of 15 mm and 22 mm cannot be used. When 23 mm fittings are used the inlet must be male and the outlet female. The direction of gas flow must be marked.

10. Vaporizers suitable for use in the breathing system must have standard 22-mm fittings or screwthreaded, weight-bearing fittings with the inlet female and the outlet male. The direction of gas flow must be indicated by arrows and the vaporizer marked “for use in the breathing system.

CLASSIFICATION

1-Regulation of output concentration

A. measured outflow

B. Concentrations calibrated

2-Method of vaporization

A. Flow over ( over surface of liquid)

B. Bubble thro ( ether bottle)

C. Draw over ( cyprane inhaler,EMO )

D. Injector ( TEC6)

3- Location

A. VOC ( in back bar)

B. VIC ( in closed circuit )

4.Plenum or not

A occupied / closed room, in which the pressure of the air is greater than that of the outside atmosphere

Here the air is forced in to the chamber

Eg – ether , copper kettle, tec

5.Compensations

A. Temperature (bimetallic strip,heater)

B. Back pressure (tec 3- 7)

C. Tilt

D. Ambient pressure ( high altitude )

6. Agent specific or not

7.Electronically controlled or not ( TEC 6, aladin casette)

8. Measured output flow rate compensation ( TEC 6 plus)

• Plenum types – have high resistance

• Draw over – low resistance

VARIABLE BYPASS VAPORISERSVARIABLE BYPASS VAPORISERS

Vaporiser has to dilute the saturated vapor as vapourpressure of most volatile anesthetics are much greaterthan the partial pressure required to produce anesthesia

Accomplished by splitting the gas flow that passes through the vaporiser

Some of the gas flows through the vaporising chamberand remainder gas through a bypass to the vaporiser outlet

Both flows join downstream to give the desired concentration

Splitting ratio

Flowmeter

Patient

VARIABLE BYPASS

FLOW OVER

• Carrier gas flows OVER liquid picking up vapor.• Efficiency improved by increasing area that carrier

gas flows over gas-liquid interface. ie. Baffles or wicks

FLOW OVER VAPORISERSFLOW OVER VAPORISERS

Performance depends onPerformance depends on

1.1. Vapour pressure of the liquidVapour pressure of the liquid

2.2. Efficiency of vaporisationEfficiency of vaporisation

3.3. Area of the gas-liquid interfaceArea of the gas-liquid interface

4.4. Velocity of carrier gas flowVelocity of carrier gas flow

5.5. Height of gas flow above the liquidHeight of gas flow above the liquid

BUBBLE THROUGH VAPORISERS:BUBBLE THROUGH VAPORISERS:

Performance depends on:Performance depends on:

•Size of the bubblesSize of the bubbles

•Depth of the liquidDepth of the liquid

•Velocity of gas flowVelocity of gas flow

Principle of the draw-over vaporizer

DRAW-OVER VAPORIZER

PLENUM VAPORIZER

INDIVIDUAL VAPORISERSINDIVIDUAL VAPORISERS

BOYLE’S ETHER BOTTLE:BOYLE’S ETHER BOTTLE:

Variable bypass – flow over or bubble through – out of systemVariable bypass – flow over or bubble through – out of system-No temperature compensationNo temperature compensation

-U inlet tube ,plunger with hood ( cowl )U inlet tube ,plunger with hood ( cowl )

-Cork with an attached chainCork with an attached chain

BOYLES BOTTLE

• Parts: (1) vaporizing bottle 300 mL (2) Metal top incorporating controls (3) Lever, plunger which is chrome plated (4) Stopper & Retaining chain

• Concentration calibrated• Flowover or bubble through• Not temperature compensated• Multiple agents• Vaporizer outside circuit

BOYLE BOTTLE

BOYLE’S ETHER BOTTLE:BOYLE’S ETHER BOTTLE:

EVALUATION OF ETHER BOTTLE:EVALUATION OF ETHER BOTTLE:

Factors influencing the vaporiser output:Factors influencing the vaporiser output:

•Temperature of the liquid in the vaporiserTemperature of the liquid in the vaporiser

•Plunger levelPlunger level

•Position of the control leverPosition of the control lever

•Volume flow of the gas through the vaporiserVolume flow of the gas through the vaporiser

•Level of liquid in the vaporiserLevel of liquid in the vaporiser

•Agitation of the vaporiserAgitation of the vaporiser

BOYLE’S BOTTLE:BOYLE’S BOTTLE:

ETHER BOTTLE:ETHER BOTTLE:

Vaporising chamber is largeCopper inlet tube and hood

HALOTHANE BOTTLE:HALOTHANE BOTTLE:No hood or plungerChromium plated inlet tubeInlet tube is plugged at the tip and a side hole 1 cm aboveControl lever scale is largerVaporising chamber is smaller than ether’s

OXFORD MINIATURE VAPORIZER (OMV)

• Variables bypass• Flowover with steel wicks• Temperature compensated• For use by multiple agents• Vaporizer outside circuit• Halothane trilene methoxyflurane ether isoflurane

OMV

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MEASURED FLOW (COPPER KETTLE & VERNITROL)

• Also known as bubble through or Vernitrol. • Flow meter-measured. Manually calculated

bypassed carrier flow.• Temperature compensated by construction

materials with high specific heat and thermal conductivity to offset cooling from vaporization induced heat loss. ie. Copper

• Amount of carrier gas (CG) O2 bubbled through is determined by a dedicated Thorpe tube flowmeter

• A valve separates the vaporizer circuit from the standard O2 & N2O flowmeters

METAMATIC VAPORIZER

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FOREGGER COPPER KETTLE 1952

GOLDMAN VAPORISERGOLDMAN VAPORISER

Variable bypass – flow over without wick – in or out of system – No temperature compensation

Designed for intermittent flow machine

When vaporising chamber is full, 2% halothane concentrationcan be achieved at a lever position of 3.

VIC – concentration may reach 3.5 % - 4.5%

Problem of the preservative - Thymol

GOLDMAN VAPORIZER

• Young’s modification of goldman

• Placing wicks

• 3—4%

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EPSTEIN-MACINTOSH-OXFORD VAPORISEREPSTEIN-MACINTOSH-OXFORD VAPORISER

Variable bypass – flow over with wick – in system – temperatureCompensation by supplied heat and flow alteration

Designed for field condition

Can be used for both spontaneous and controlled ventilation

A ventilating bellows has to be added in the circuit forcontrolled ventilation

EMO vaporizer 1953• Variable bypass• Incomplete vapourizatio • Low resistance• Agent-specific for ether or may not be• Temperature compensated by bellows, • Temperature stabilized by water jacket, • Transportable but heavy (10kg). .

EPSTEIN MACINTOSH OXFORD VAPORIZER 1952 (EMO)

E.M.O VAPORISER

FLUTEC

• All TEC

Variable bypass

Plenum

Temperature compensated

Concentrations calibrated

Flow compensated – by using wicks ( except TEC 2 )

• TEC 2- 4 – not agent specific• Backpressure (pumping effect) compensation starts

from TEC 3• Anti spill proof starts from TEC 4• Agent specific starts from TEC 4• Selectatec starts from TEC 4• Color coding starts from TEC 5 ( but our TEC 3

having color coding)• Tilt compensation from TEC 6• Barometric pressure compensation TEC 7

But TEC 2 used only for HALOTHANE

• Bimetallic strip(temp compensating device )

may be in inside the vaporizer chamber

or in bypass channel

• TEC 5 PUMPING EFFECT> TEC 4• INTERNAL BAFFLES TEC5

FLUTEC Mk-IIIFLUTEC Mk-III

Variable bypass – flow over with wick – out of system – Variable bypass – flow over with wick – out of system – Temp. compensation by flow alteration – Temp. compensation by flow alteration – agent specific ( Halothane )agent specific ( Halothane )

Bypass is located concentrically within the vaporising chamberFlow alteration is by a bimettalic stripVolume of vaporising chamber is 270 ml, wick retains 35 mlMaximum 5%Accuracy is good up to 3% with all flows

FLUTEC Mk - IIIFLUTEC Mk - III

TEC – 5 VAPORISERSTEC – 5 VAPORISERS

•Meant for isoflurane, sevofluraneMeant for isoflurane, sevoflurane

•Improvised to check the pumping effectImprovised to check the pumping effect

•Accuracy is assured in clinically used flow ratesAccuracy is assured in clinically used flow rates

•Liquid anesthetic can’t enter the bypass channelLiquid anesthetic can’t enter the bypass channel

•Fitted with coded filling systemFitted with coded filling system

TEC Mk 5 VAPORISERS:TEC Mk 5 VAPORISERS:

TEC Mk 5 VAPORISER

TEC 6- why • Desflurane BP 22.8 ºc• So at room temperature – will be in vapor or as gas form ( u

wont able to see even drops of desflurane)• So we may not know how much it is delivered to the patient

if u give it by scimmelbusch mask like ether• Suppose if u use desflurane by other Tec - high output will

be delivered • Suppose if u are reducing desflurane output by diluting its

vapor molecules in other Tec – u need to keep FGF of 73 L/min to have 1% vapor

• If u supply desflurane in ordinary Tec – all desflurane vapoured in room tem

• This leads to excessive cooling of vaporizer-lead on to low output

• So Desflurane needs special (controlled vaporization) vaporizer

TEC 6

• Parts

1. It has 2 independent gas circuits in parallel

1.FGF inlet circuit – passes thro R1(fixed restrictor)

2.Vapor circuit – passes thro R2 (variable restrictor, ie the dial setting)

2.Differential pressure transducers

3.Control electronics

4.Pressure regulating valve

5.Desflurane resorvoir(heating sump)

6.Shut off valve

Tec 6 – how it works

Sump (electrically heated) is heated up 39ºc

Vapor pressure in sump – reaches 2atm absolute

Shutt of valve opened ( dial setting on)

Pass thro R2

R2 reduces pressure to 1.1atm absolute

After R2 vapor joins with FGF

When FGF rate – constant

Back pressure to the diaphragm of differential pressure transducer(dpt)

DPT conveys pressure diff between fgf circuit & vapor circuit

Now control electronics – act on pressure regulative valve

Pressure in vapor circuit = pressure in FGF circuit

Now this is the working pressure of vaporizer

• If FGF rate constant – working pressure – constant• If u increase the FGF rate – working pressure is also

increased• But change in FGF rate or dial setting – will not

change vapor pressure ( vapor output is constant)

Special operating features of TEC 6

• Once vaporizer – connected to power supply – the vaporizer starts to heat the sump automatically

• No separate switch to on heaters

• Warm up time – 5-10 mins• Front panel has 5 LED lights

Tec 6 LEDs – top to bottom

• Operational LED (ready to use) - green

• No output LED - red

• Low agent LED(refilling is required) – amber

• Warm up LED - amber

• Alarm Low battery LED – amber

Amber LED

• Amber color LED - Emits light during

Warm up

Agent <50ml

Muted the alarm for >120 secs

Low battery

If press the mute button continuosly – vaporizer will go for self testing

RED LED• If fluid level < 20ml• Tilting >105 º ( > 15 deg from vertical axis)• Power failure• Internal malfunction

There is 10 seconds delay from the time detected malfunction to time alarm activated

TEC 6 - LCD

• Battery – 9 volt comes for 1 year• LCD bars (20 small bars, instead of fluid column

in others)- receives signal from sump• If heaters switched off or Low agent – LCD bars

also will drop• Upper most LCD bar = 390 ml in sump• Middle bar = 240 ml • Lowest = only 60 ml

TEC 6 • Beginning of warm up – all LED s flash for 1 sec with

alarm• Tec 6 tilt proff - when tilt > 105 º - shutts of vaporizer• Up to 90 º u can use the vaporizer• Filling speciality

SAF –T-FIT – specific filler nozzle in desflurane bottle

Nozzle is attached with filler port in vaporizer

then turned upward and invert the bottle

• Now the vaporiser is filled

• If u fill the vaporiser when LCD bar showing < 240 ml ( below middle bar)- port will accept the whole bottle

• Once bottle emptied – bottle turned to starting (upward) position

• Now the filler port ejecting nozzle of bottle

• You can fill when vaporizer on flow

• Overfilling prevented

• Dial setting – 1 – 18%

TEC 6 CHECK OUT

• 1-Press and hold the mute button until all lights and alarms activated.• 2-Turn on to at least 1% and unplug the electrical connection. A "No Output"alarm should ring within seconds. This tests battery power for the alarms.

This step is crucial in relation to the quick emergence characteristics of this agentany interruption in its supply must be noted and responded to at once

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TEC 6

• Tell me one disadvantage of Tec 6 ?

Not barometric pressure compensated so dial settings to be adjusted I tell u why ?

High altitude & vaporizer

• For classical plenum vaporizers,

the percentage output increases roughly in proportion to the fall in barometric pressure,

But a smaller partial pressure increase.• Depth of anesthesia depends on partial pressure• The changes in partial pressure are relatively small, • So normal vaporizer settings work as expected at

altitude

TEC & barometric compensation

• At 20º c SVP of isoflurane 238 mmhg• At high altitude temperature rises to 35º c – SVP rised

to 450mmhg• Increase pressure in vaporizing chamber bend the

bimetallic strip• So the bimetallic strip decrease FGF to the vaporizing

chamber – reduce the vapor output – so same concentration is delivered = same anesthetic potency

High altitude & Tec 6 • The percentage delivered is essentially held constant• so partial pressure FALLS in proportion to the fall in

atmospheric pressure. • The dial setting should be turned up to compensate

• Required dial setting = normal dial setting * 760 mmhg/ ambient pressure (mmhg)

• I mean the vapor pressure of deslurane at outlet to the pt is always constant becoz 2 pressure resistors

SAFETY FEATURESVAPORIZER

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INTERLOCK SYSTEM

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INTERLOCK DEVICES

• Selector valve

• Selectatec system

• Back bar devices

• Ohio switch

• Drager lock

BACK BAR

• Safety Selectatec’ system

Opening more than 2 vaporizer not possitbe at a time

SELECTA TEC

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Fillers • Types

Funnel fillers – simple funnel there (most of our vaporisers)

Keyed filler – specific attached to vapor bottle and vaporiser ( not in our institute)

Quick filler – sevoflurane vaporizer is (eg our theatre sevo)

SAF-T-FIT – special for desflurane ( we r having)

Easy filler – Tec 7 ( bottle adapter)

FILLING – FUNNEL

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KEYED FILLING

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EASY FILL

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SAFE –T-FIT

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1. Difficulty in filling

2. Misalignment of adaptor in filler receptacle

3. Adaptor not sealing at the bottle end

4. Leak in the bottle adaptor

5. Air bubbles.

6. Lost bottle adaptor

7. Failure of keyed system

8. Liquid leaks

AGENT SPECIFIC FILLING SYSTEMS PROBLEMS

9. VAPORIZER TIPPING

If filler receptacle on vaporizer extends beyond the base → it cannot be set upright on a flat surface → this can cause tipping prevented by setting the vaporizer receptacle at the edge of the surface or a ring can be fitted at the base that extends below the projection of the filler reeptacle

10.POOR DRAINAGE

11.BROKEN INNER TUBE

AGENT SPECIFIC FILLING SYSTEMS PROBLEMS

ADU ALADIN CASSETTE

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ALADIN CASSETTE

• Cassettes – color & magnetic coded • Handle • Filler• 10% fluid only – messages in machine& alarm • Vaporizer oultet flow-controlled by CPU• Cassette temp<18C – fan activated• Over fill protection ( air – deactivate it)• Temperature maintenance- brass shell around the

cassette

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DRAGER VAPORIZER

• VAPOR 19.1• Calibration with air• Over fill protection even the vaporizer in on

position• VAPOR 2000 ( DRAGER)• Air calibration• DRAGER D• For desflurane

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PENLAN DELTA

• O2 – CALIBRATION

• TEMP COMPENSATION- 1- 2HRS

• PENLON ALPHA

• FOR DES

• FAST WARM UP SLOWER POWER CONSUMPTION

• CALCULATE THE AMOUNT OF DES USED FOR EACH CASE

• CPU

• CAUTERY MAY AFFECT

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HAZARDS

• Wrong agent• Tipping• Overfilling • Reversed flow• Control dial in wrong position• Leaks• Vapor leak • Cross contamination

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• TIPPING• Liquid from vaporizing

Chamber→bypass/outlet→high output• Drained before moving• OVERFILLING• In majority, the design of the filling port and agent

specific filling systems prevent this• During filling do not:

Turn the dail ON/Unscrew the bottle adaptor

HAZARDS

• Reversed flow• Inlet male & outlet female• Increased output• Physical damage• Obstruction to fresh gas flow• Interlock malfunction

HAZARDS

VAPOURISER check

• Check for the required vaporizer• Check for the fluid level• Filler caps and draining port should be tight• Check for the correct seating and locking of the a

detachable vaporizer• Ensure power supply if electrically operated.

• VO: Vapor Output (mL/min)

• CG: Carrier Gas Flow (mL/min)

• VP: Vapor Pressure (mmHg)

• BP: Barometric Pressure (760mmHg)

• VAA%: Volatile Anesthetic Agent Concentration

VO = CG x VP VO = Total Gas Flow

BP – VP VAA%

Vapor output

Examples

• Halothane: VP 243 mmHg• CG: 100 mL/min

VO = (100 mL/min)(243mL/min) = 24300 = 47mL/min

(760mmHg – 243mmHg) 517

If 1% of Halothane is desired:

47mL/min = 4700mL/min Total gas flow needed

0.01

HALOTHANE

• If 100mL/min of O2 enters , 147ml of gas will exit (100mL of O2 picked up 47mL of Halothane)

• % Halothane exiting is 32% (243/760=0.32) at 1 atm

• If Only 1% Halothane needed for anesthesia, the 32% needs to be diluted with 4553mL/min

• 4700mL/min – 147mL/min = 4553mL/min

Isoflurane • Avagadro law• 1.5% iso 5 litre/min flow• Total /hr = 300l• 1.5% = 300* 1.5% = 4.5l• 184.5 mol wt iso – 22.4l• 4.5 – 37 gms• Sp gravity 1.496• 37/1.496 = 24.7 ml

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IDEAL VAPORISER CHARACTERISTICS:IDEAL VAPORISER CHARACTERISTICS:

•Performance should not get affected by changes in fresh gas flow, volume of the liquid,ambient temp and pressure, decrease in liquid temp,pressure fluctuation due to mode of respiration

•Low resistance to flow

•Lightweight with small liquid requirement

•Economy and safety in use with minimal servicing requirements

•Corrosion and solvent resistant construction

Are we having such type of a vaporiser…?Are we having such type of a vaporiser…?

Concluding…

Inhalational anesthesia is the most important part of modern balanced anesthesia

To efficiently and safely conduct an inhalational anesthesia,a proper knowledge of a vaporiser is a must….

THANK YOU

VAPORIZER Lakshmanraj

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