BY

DR. S. PADMANABHA

PROF. & H.O.D.,

DEPT. OF ANAESTHESIOLOGY,

YENEPOYA MEDICAL COLLEGE

MANGALORE – 575 018.

VAPORIZERS

VAPORIZERS

• INTRODUCTION

• BASIC PHYSICS

• CLASSIFICATIONS

• OLD VAPORIZERS

• NEWER VAPORIZERS

INTRODUCTION

• Both inhalational agent & vaporizers made rapid progress.

• Today we are able to administer set concentrations accurately.

ANAESTHESIA MACHINE

ANAESTHESIA WORK STATION

POSITION OF THE VAPORIZERS

STANDBY VAPORIZERS

DESFLURANE VAPORIZER

DESFLURANE

What is vaporizers?

An instrument designed to….

• Facilitate change of liquid into vapor

• Add controlled amount of vapor in flow of gases

Why vaporizer needed?

• Liquid Inhalational agents need to be vaporized

• Widely differing properties of agents, hence specific vaporizers

• Potent agents require accurate conc. control

BASIC PHYSICS

• Gas-It is a substance that appears in gaseous state under standard condition of temperature and atmospheric pressure

• Vapor - is the gaseous phase of the agent,which is normally liquid at room temperature and atmospheric pressure

CRITICAL TEMPERATURE• Critical temperature: is the temperature below

which gas can be liquefied by applying pressure.

• THE CRITICAL TEMPERATURE, GAS/VAPOR

BOILING POINT

• Boiling Point: Boiling point of liquid is the temperature at which its vapor pressure is equal to atmosphereic pressure.

Boiling point SVP

Halothane 50.2 243Isoflurane 48.5 238Sevoflurane 58.5 160Desflurane 23.5 664

VAPORIZER CONSTRUCTION

• Specific heat of agent: Materials with highspecific heat are preferred in construction ofthe vaporizers.

• Latent heat of Vaporization

• Thermal Conductivity: High thermalconductivity is desirable in vaporizerconstruction.

CLASSIFICATION

Based on regulating output concentration

• Variable bypass

• Measured flow

• Electronic vaporizers

Based on method of vaporization

• Flow over

• Bubble through

• Injection

CLASSIFICATIONS (Contd…..)

Based on method of temperature Compensation

• Mechanical thermocompensation• Supplied heat • Computerized thermocompensation

Based on location of the vaporizer

• Plenum • Low resistance (Draw Over)

Based on agent specificity

• Agent specific • Multiple agent

Automatic Temp. Compensating Devices

Bimetallic Strip Expansion element

Expansion or contraction property of a special liquid inside bellows used to control the valve

Two metals of different coefficients of thermal expansion are fixed together. Depending upon VC temperature the strip move away or towards control valve.

OLD VAPORIZERS

MORTON’S EITHER INHALER

Draw over, flow over with wicks, concentration notcalibrated, temperature not compensated, agentspecific.

OPEN DROP METHOD

Draw over, flow over without wicks,concentration not calibrated, temperaturenot compensated, multiple agent.

EPSTIEN MACINTOSH OXFORD (E.M.O.)

Draw Over, Concentration calibrated,Flow over,

Temperature compensated by water jacket and agent specific,

can be used any where.

GOLDMANS VAPORIZER

Plenum or Draw over type ,variable bypass, flowover, temperature not compensated, concentrationpoorly calibrated, multiple agent, both inside andoutside circle.

BOYLES BOTTLE

Plenum type, variable bypass, flow over or bubble through,concentration poorly calibrated, temperature notcompensated, agent specific, out of circle.

TEC - 2

Plenum type, concentration poorly calibrated, flow over with wicks,

temperature compensated, out of circle and agent specific.

TEC - 3

Plenum type, variable by pass, flow over with wicks, temperature

compensated, concentration calibrated, out of circle, agent specific.

TEC - 4

Plenum type, variable bypass, flow over with wicks, temperature

compensated, concentration calibrated, out of circle, agent specific.

NEWER VAPORIZER

TEC 5

Plenum type, concentration calibrated, variable bypass,

flow over with wicks, out of circle, agent specific with keyed filling.

TEC - 7

Concentration calibrated, plenum type, Variable bypass,

Flow over with wicks, Temperature compensated,

out of circuit, agent specific

TEC - 7

The innovative non-spill system in the Tec.7vaporizer limits movement of liquid agent ifthe vaporizer is lifted or inverted. Thisprotects its internal components and helps tomaintain output within clinically acceptablelimits.

TEC – 6 DESFLURANE VAPORIZER

It is a electrically heated, dual circuit gas/vapor blender, constant-temperature, agent specific and out-of-circuit vaporizer.

PRINCIPLE OF DESFLURANE VAPORIZER

PRINCIPLE OF DESFLURANE VAPORIZER (Contd…)

TEC - 6

Flow meters [1]. The fresh gas travels through pipe [2]. None of the fresh gas goes to the vaporizing chamber [4]. The vaporizing chamber iselectrically heated [3]. Using sensors for feedback, the temperature is kept very constant. The heating causes the Desflurane to become a gas

under pressure [4] and this travels down pipe [5]. The flow of Desflurane is resisted by two valves [6,13]. Valve [6] is the valve that you

control when you set the dial to a particular concentration. When you increase the concentration setting, the valve [6] opens a bit and lowers theresistance, allowing more Desflurane to flow through. Valve [13] is an electronically controlled valve. Computer [12], the vaporizer's "brain", isable to also alter the flow of Desflurane by controlling valve [13]. i.e. both you and the computer can adjust the desflurane injection rate. TheDesflurane then goes via pipe [7] and meets the fresh gas at [8]. The Desflurane mixes with the fresh gas [8] and a final concentration emergesfrom the exit of the vaporizer [9].Fresh gas flow resistor (10), Fresh gas flow & Desflurane vapor balancing unit(11)

THE GE ALADIN CASSETTE VAPORIZER

It is a electronically controlled, variable bypass, constant-temperature,multiple agent specific, and out-of-circuit vaporizer.

SAFETY FEATURES

• Select – TEC mount

• Filling devices

• Interlocking

• Colour coding

FILLING DEVICES

• Easy fill system

• Funnel fill

• quick fill.

The male adaptor that fits into the vaporizer filler receptacle.

CAP OF BOTTLE REMOVED

Quick fill system

COLOR CODING OF VAPORIZERS

• ISOFLURANE SEVOFLURANE HALOTHANE

PURPLE YELLOW RED

HAZARDS OF VAPORIZERS

• Incorrect agent

• Tipping

• Simultaneous inhaled agent administration

• Overfilling

• Leaks

• Electronic failure

• Pumping effect

• Pressurizing effect

PUMPING EFFECT

CONCLUSION

• Proper maintenance will help to deliver theaccurate concentrations of the anaestheticvapor.

• In the future anaesthetic depth sensor may beavailable as an integral part of the vaporizer.

THANK YOU