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Anaesthesia
vaporizers
Dr Rahul
Varshney
Introduction
▪ A vaporizer (anesthetic agent or vapor
delivery device) changes a liquid
anesthetic agent into its vapor an...
Historical aspects
▪ ‘Inhalational Anesthesia’ tried by early ‘clinicians’ from time immemorial
▪ Historical records show ...
Historical aspects
▪ The main ‘reviver’ of ether was Kurt Schimmelbusch and his ‘mask’
▪ Contraption made with wires and l...
Historical aspects:
▪ With deeper insights into physical principles, properties and laws
▪ Advances for development of mor...
Physical principles:
▪ Heat of Vaporization
▪ The Number of calories required to vaporize 1 ml. of the liquid
▪ Latent hea...
There are a number of ways of classifying vaporizers:
Mechanism for adding anaesthetic vapour to the fresh gas flow
▪ Vari...
Mechanism for adding anaesthetic vapour to the fresh gas flow
Volatile anaesthetics are too potent to be used at their sat...
Bypass vaporizer
The internal resistance of the vaporizer
▪ Draw-over vaporizers have low internal resistances to gas flow. The patient’s
i...
Temperature compensation
▪ Latent heat of vaporization, when Left unchecked, the temperature of the
remaining liquid anaes...
The concentration of anaesthetic produced by the
vaporizer depends on the fraction of fresh gas that is
diverted into the ...
Bimetallic strips
The bimetallic strip consists of strips two different metals joined together.
The metals have different ...
Characteristics of Ideal VAPORIZER
▪ Performance not affected by changes in
▪ FGF,
▪ Volume of liquid agent,
▪ Ambient tem...
Features of modern vaporizer
▪ Variable bypass
▪ Fresh gas splits into bypass gas and carrier gas
▪ Flow over
▪ Carrier ga...
Property TEC 4, Vapor
19n, 2000,
Aladin
TEC 5 TEC 7 Vapor 19n Vapor 2000 D Vapor
TEC 6 Des.
Principle of
vaporization
Flow...
OLD VAPORIZERS
MORTON’S ETHER INHALER
Draw over, flow over with wicks, concentration not calibrated,
temperature not compe...
OPEN DROP METHOD
Draw over, flow over without wicks, concentration not calibrated,
temperature not compensated, multiple a...
BOYLES BOTTLE (1920)
Plenum type, variable bypass, flow over or bubble through, concentration
poorly calibrated, temperatu...
GOLDMANS VAPORIZER (1959)
Plenum or Draw over type ,variable bypass, flow over, temperature not
compensated, concentration...
Oxford miniature vaporizer (OMV)
Variable bypass, draw-over vaporizer, not actively temperature compensated, but it
does i...
EPSTIEN MACINTOSH OXFORD (E.M.O.) (1952)
Draw Over, Concentration calibrated, Flow over, Temperature compensated
by water ...
TEC - 2
Plenum type, concentration poorly calibrated, flow over with
wicks, temperature compensated, out of circle and age...
TEC - 3
Plenum type, variable by pass, flow over with wicks, temperature
compensated, concentration calibrated, out of cir...
TEC - 4
Plenum type, variable bypass, flow over with wicks, temperature compensated,
concentration calibrated, out of circ...
NEWER VAPORIZER
TEC 5
Plenum type, concentration calibrated, variable bypass, flow over with wicks,
out of circle, agent s...
TEC - 7
Concentration calibrated, plenum type, Variable bypass, Flow over with wicks,
Temperature compensated, out of circ...
Advantages
• Easy to use and reliable.
• Properly calibrated modern variable bypass vaporizers are accurate to +/- 15% of ...
Problems of Desflurane
▪ Desflurane is much more volatile than all the other inhalationals.
▪ Its boiling point is low -- ...
• In the above figure, note different vapor pressure-temperature relationships between common
volatile agents
• Desflurane...
 Specifically designed to deliver Desflurane
 Described as a gas/vapor blender than as a vaporizer.
 It is heated elect...
 The pressure in the vapor circuit is electronically
regulated to equal the pressure in the fresh gas
circuit.
 At a con...
Advantages
• Comparable accuracy to variable bypass Tec 5 vaporizers; +/- 15% of dialled setting.
• Unaffected by ambient ...
Schematic diagram of the TEC 6 vaporizer.
There are two mechanisms that govern the release
of desflurane vapour into the F...
Aladin Cassette Vaporizer System
▪ A Novel system
▪ Single vaporizer capable of delivering 5 different anaesthetic
agents
...
Advantages
• Automated recognition of the agent inserted.
• On-screen data showing agent levels and anaesthetic usage.
• A...
▪ Similar to tec 4,5 vaporizers.
▪ The interlock on Dräger machines continues to function if any
vaporizers are removed.
▪...
Drager 2000
• Is one of two tippable vaporizers
(ADUcassettes are the other).
• The dial must first be rotated to a "T"
se...
Safety features
▪ Color specific (for each agent)
▪ Keyed fillers bottles
▪ Low filling port
▪ Vaporizers are locked into ...
Filling system
▪ Bottle Keyed System
▪ Funnel Fill System
▪ Keyed Filling System
▪ Quick-Fill System
▪ Easy-Fill System
▪ ...
FUNNEL FILL
▪ Vaporizers may be filled by a conventional
funnel-fill mechanism, in which the liquid
anesthetic is simply p...
KEYED FILL
In this system, an agent-specific filler tube is
used, one end of which slots into a fitting on the
vaporizer, ...
▪ The bottle has a permanently
attached, agent-specific filling
device that has three ridges that fit
into slots in the fi...
EASY FIL
▪ A color coded bottle adaptor is attatched to
bottle and then fitted into the vaporizer.
▪ A drain plug is there...
Hazards
1. Incorrect Agent
2. Tipping
3. Overfilling
4. Reversed Flow
5. Control Dial in Wrong Position
6. Leaks
7. Vapour...
Hazards
▪ Tipping
▪ If tipped >45 degrees-liquid can obstruct the outlet valves
▪ Treatment: Flush for 20-30 min at high f...
Hazards
▪ Misfilling
▪ Vaporizers not equipped with keyed filling lead to misfiling.
▪ Contamination
▪ It occurs by fillin...
THANK YOU
Anaesthesia Vaporizers
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Anaesthesia Vaporizers

Anaesthesia vaporizers for inhalational anaesthetic agents. Principal, classification, types, hazards

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Anaesthesia Vaporizers

  1. 1. Anaesthesia vaporizers Dr Rahul Varshney
  2. 2. Introduction ▪ A vaporizer (anesthetic agent or vapor delivery device) changes a liquid anesthetic agent into its vapor and adds a controlled amount of that vapor to the fresh gas flow to the breathing system. Up to three vaporizers are commonly attached to an anesthesia machine, but only one can be used at a time.
  3. 3. Historical aspects ▪ ‘Inhalational Anesthesia’ tried by early ‘clinicians’ from time immemorial ▪ Historical records show use of “Soporific sponges” soaked in ‘medicinal elixirs’ ▪ Actual use of easily ‘vaporizable substances’ came much later, in 18th century, 16th October 1846 to be exact ▪ WTG Morton used his ‘ Letheon’ inhaler - Ether inhaler first time to achieve surgical anesthesia, as a public demonstration, in the history of mankind. ▪ Thus ether then chloroform again back to ether, Led to evolution of various devices used for vaporization of these liquids
  4. 4. Historical aspects ▪ The main ‘reviver’ of ether was Kurt Schimmelbusch and his ‘mask’ ▪ Contraption made with wires and layer of gauze pieces/used along with ‘open ether - drop by drop method’ for administration of ether. ▪ “Yankauer’s mask” in 1904, Flagg’s can/ KEM Bottle, ▪ More sophistication: Epstein Macintosh Oxford (EMO) vaporizer with Oxford inflating bellows (OIB) ▪ “Anesthesia Machine” was invented.
  5. 5. Historical aspects: ▪ With deeper insights into physical principles, properties and laws ▪ Advances for development of more sophisticated devices ▪ As a result Oxford Miniature Vaporizer (OMV), Copper Kettle. ▪ halogenated compounds like halothane/halogenated ethers ▪ has produced the Tec series of vaporizers. ▪ Presently available modern vaporizers ▪ advanced in their construction capable of delivering precise, predictable and calculated/ constant concentration of the Volatile anesthetic agent. ▪ Thus the humble beginning has evolved in to a precision perfect and an analytical science.
  6. 6. Physical principles: ▪ Heat of Vaporization ▪ The Number of calories required to vaporize 1 ml. of the liquid ▪ Latent heat of vaporization ▪ The Number of calories needed to convert 1 gram of liquid to vapor without a temperature change ▪ Temperature of remaining liquid falls and may decrease rate of vaporization ▪ Specific heat ▪ The quantity of heat energy required to increase the temperature of a 1 gm. of a substance/1 ml. of a liquid by 10 Celsius is called the Specific Heat of the substance/ liquid. ▪ Thermal conductivity ▪ Measure of speed with which heat flows through a substance.
  7. 7. There are a number of ways of classifying vaporizers: Mechanism for adding anaesthetic vapour to the fresh gas flow ▪ Variable bypass ▪ Measured flow The internal resistance of the vaporizer ▪ High: plenum vaporizers ▪ Low: draw-over Temperature compensation ▪ High thermal conductivity and specific heat capacity of the jacket (a ‘heat sink’) ▪ Automatic adjustment of the splitting ratio: 1. Bimetallic strip 2. Bellows 3. Electronically controlled
  8. 8. Mechanism for adding anaesthetic vapour to the fresh gas flow Volatile anaesthetics are too potent to be used at their saturated vapour pressure and must therefore be diluted to a safe concentration before being delivered to the patient. This is commonly achieved in one of two ways’ ▪ Variable bypass vaporizers (e.g. most modern vaporizers, apart from the Tec 6) split the fresh gas flow into two streams. One stream enters a vaporization chamber and leaves fully saturated with anaesthetic vapour, whilst the remainder of the fresh gas bypasses this chamber. The two gas flows are reunited downstream to produce the desired final concentration. Altering the FGF does not alter the ratio between the flows in the two streams (splitting ratio) and therefore does not alter the final concentration. ▪ Measured flow vaporizers (e.g. the Tec 6 desflurane vaporizer) use a separate heated and pressurized vapour stream that is precisely injected into the FGF. Increasing the FGF dilutes the output and therefore an automated mechanism compensates for this.
  9. 9. Bypass vaporizer
  10. 10. The internal resistance of the vaporizer ▪ Draw-over vaporizers have low internal resistances to gas flow. The patient’s inspiratory effort is sufficient to draw fresh gas through the vaporizer and draw- over vaporizers are therefore useful in the field where pressurized gas may not be available. Mechanisms to improve the accuracy of anaesthetic delivery, such a baffles and temperature compensation increase resistance and are not usually present in draw-over vaporizers, leading to unpredictable performance. Examples, the Goldman, the Oxford Miniature Vaporizer (OMV) and Epstein and Macintosh of Oxford (EMO) vaporizers. These vaporizers are used within the breathing system. ▪ Plenum vaporizers in contrast rely on pressurized gas flow rather than the patient’s inspiratory effort. They have a high internal resistance and are used with continuous flow anaesthetic machines. A plenum vaporizer should saturate all gas that passes through the vaporization chamber in order to achieve a consistent output, even at high FGFs. Examples: Boyle’s bottle, the Copper kettle, the Tec 5 series and the Aladin cassette. These vaporizers are used outside the breathing system.
  11. 11. Temperature compensation ▪ Latent heat of vaporization, when Left unchecked, the temperature of the remaining liquid anaesthetic will fall significantly, along with its saturated vapour pressure and therefore lead to a reduction in the output of the vaporizer. ▪ The first method used to compensate for the latent heat of vaporization is to use a heat sink, such as a water bath (Boyle’s bottle) or a large mass of copper. Modern vaporizers are still made of large masses of metal for this purpose. ▪ Invariably though, there will be some drop in temperature within the vaporizer as it is used. To maintain a constant output, this drop in temperature and saturated vapour pressure of the anaesthetic must be compensated for. This is achieved by the use of devices such as bimetallic strips, bellows or electronic control.
  12. 12. The concentration of anaesthetic produced by the vaporizer depends on the fraction of fresh gas that is diverted into the vaporizing chamber. This fraction is governed by the calibrated control dial. The proportion bypassing divided by the proportion entering the vaporizing chamber is known as the splitting ratio. In order to ensure that the end concentration is controlled only by the splitting ratio and not by variations in the amount of anaesthetic leaving the vaporizing chamber, the diverted gas must always become fully saturated with vapour before it re-joins the bypass gas. This is achieved using wicks that increase the surface area for evaporation of the anaesthetic liquid and baffles that direct the incoming gas down closer to the surface of the liquid. These features significantly increase the internal resistance of the vaporizer.
  13. 13. Bimetallic strips The bimetallic strip consists of strips two different metals joined together. The metals have different coefficients of thermal expansion, and they are wound into a coil. As the temperature increases, one metal will expand more than the other, causing the coil to loosen. Similarly, the coil will tighten as the temperature decreases. At the centre of the coil is a pointer, which moves across a calibrated dial as the coil tightens or loosens so that the temperature can be read. ▪ Advantages Cheap. ▪ Disadvantages Limited accuracy and slow response times.
  14. 14. Characteristics of Ideal VAPORIZER ▪ Performance not affected by changes in ▪ FGF, ▪ Volume of liquid agent, ▪ Ambient temperature & pressure, ▪ Decrease in temperature & pressure ▪ Low resistance to flow ▪ Light weight with small liquid requirement ▪ Economical and safe to use ▪ Corrosion and solvent-resistant
  15. 15. Features of modern vaporizer ▪ Variable bypass ▪ Fresh gas splits into bypass gas and carrier gas ▪ Flow over ▪ Carrier gas flows over the surface of the liquid volatile agent in the vaporizing chamber ▪ Temperature compensated ▪ Equipped with automatic devices that ensure steady vaporizer output over a wide range of ambient temperatures ▪ Agent-specific ▪ Only calibrated for a single gas, usually with keyed fillers ▪ Out of circuit
  16. 16. Property TEC 4, Vapor 19n, 2000, Aladin TEC 5 TEC 7 Vapor 19n Vapor 2000 D Vapor TEC 6 Des. Principle of vaporization Flow over, Flow over Flow over Flow over Flow over Gas-vapor blender Carrier gas flow Variable bypass Variable bypass Variable bypass Variable bypass Variable bypass Dual circuit Capacity mls. With dry wicks With wet wicks 135 100 300 225 225 200 140 360 280 D-vapor 300 TEC 6: 425 Thermo- compensation Automatic Automatic Automatic Automatic Automatic Thermostatically controlled at 39 0C. Position Out of circuit Out of circuit Out of circuit Out of circuit Out of circuit Out of circuit specificity Agent-specific Agent-specific Agent-specific Agent-specific Agent-specific Agent-specific Low flow suitability Not very good Good Very Good Good Very Good Very Good Comparative properties
  17. 17. OLD VAPORIZERS MORTON’S ETHER INHALER Draw over, flow over with wicks, concentration not calibrated, temperature not compensated, agent specific.
  18. 18. OPEN DROP METHOD Draw over, flow over without wicks, concentration not calibrated, temperature not compensated, multiple agent.
  19. 19. BOYLES BOTTLE (1920) Plenum type, variable bypass, flow over or bubble through, concentration poorly calibrated, temperature not compensated, agent specific, out of circle. Advantages • Could be used with several different anaesthetic agents. • Full saturation of the vapour chamber gas flow was possible. Disadvantages • No temperature compensation so volatile output fell as the reservoir cooled. • The concentration of anaesthetic delivered to the patient was imprecise. • Tipping Boyle’s bottle could lead to dangerous rises in anaesthetic concentrations Used with early continuous flow anaesthetic machines to deliver ether, trichloroethylene or chloroform.
  20. 20. GOLDMANS VAPORIZER (1959) Plenum or Draw over type ,variable bypass, flow over, temperature not compensated, concentration poorly calibrated, multiple agent, both inside and outside circle. Advantages • Small and cheap. • Simple to use and service. • Lightweight and portable. • Restricted output prevents halothane overdosing. Disadvantages • Variable output that is difficult to measure. • No temperature compensation. • Unsuitable for use with less potent anaesthetic agents, because it is inherently inefficient. • There is a risk of anaesthetic agent spillage into the breathing system.
  21. 21. Oxford miniature vaporizer (OMV) Variable bypass, draw-over vaporizer, not actively temperature compensated, but it does incorporate an ethylene glycol heat sink, low resistance Advantages • Portable. • Robust and easily serviceable. • Most volatile agents can be used by simply switching the interchangeable dials. • When the control dial is switched off, volatile agent cannot easily spill into the breathing circuit if the vaporizer is tilted or inverted. • An ethylene glycol heat sink buffers temperature changes, to an extent. • Metal mesh wicks help increase the output of the vaporizer. • Acceptable accuracy over a range of flow rates and tidal volumes. Disadvantages • Not temperature compensated. • Small 50 ml reservoir empties quickly.  The OMV remains in current use as part of the British military’s Triservice apparatus for delivering anaesthesia in the field, typically with isoflurane, but also sevoflurane.
  22. 22. EPSTIEN MACINTOSH OXFORD (E.M.O.) (1952) Draw Over, Concentration calibrated, Flow over, Temperature compensated by water jacket and agent specific, can be used any where. The accurate and precise delivery of ether irrespective of temperature Advantages Temperature compensation. Reliable and generally safe. Disadvantages Bulky and heavy (it weighs 10 kg). Requires high gas flow to deliver anaesthetic agents accurately. The pumping effect of positive pressure ventilation may lead to dangerous surges in volatile output. Designed specifically for use with ether, which is now obsolete in the developed world.
  23. 23. TEC - 2 Plenum type, concentration poorly calibrated, flow over with wicks, temperature compensated, out of circle and agent specific.
  24. 24. TEC - 3 Plenum type, variable by pass, flow over with wicks, temperature compensated, concentration calibrated, out of circle, agent specific.
  25. 25. TEC - 4 Plenum type, variable bypass, flow over with wicks, temperature compensated, concentration calibrated, out of circle, agent specific.
  26. 26. NEWER VAPORIZER TEC 5 Plenum type, concentration calibrated, variable bypass, flow over with wicks, out of circle, agent specific with keyed filling.
  27. 27. TEC - 7 Concentration calibrated, plenum type, Variable bypass, Flow over with wicks, Temperature compensated, out of circuit, agent specific ▪ The latest model of the TEC series ▪ It delivers Isoflurane, Sevoflurane, Enflurane and Halothane efficiently ▪ Accommodates 225 mL of anesthetic agent. ▪ Non-spill system limits movement of liquid agent ▪ if the vaporizer is tilted or inverted ▪ helping to protect internal components.
  28. 28. Advantages • Easy to use and reliable. • Properly calibrated modern variable bypass vaporizers are accurate to +/- 15% of the dial setting for all flows between 200 ml.min-1 and 15 l.min-1 at 21°C. • This type of vaporizer does not require a power source. Disadvantages • High internal resistance so must be used ‘out of circle’. • The heat sink makes the vaporizer heavy – another reason why this type of vaporizer is not suitable for use in the field. • There are no alarms to indicate that the level of liquid anaesthetic inside the vaporizer is low. • Temperature compensation only works within a reasonable range of ambient temperatures. • If the vaporizer is used in an extremely hot or cold environment it will deliver anaesthetic unreliably.
  29. 29. Problems of 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
  30. 30. • In the above figure, note different vapor pressure-temperature relationships between common volatile agents • Desflurane falls outside the grouping • Hence, Not surprisingly, special vaporizer is required for desflurane.
  31. 31.  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 Datex-Ohmeda Tec 6 Vaporizers for Desflurane (1989)
  32. 32.  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.
  33. 33. 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. 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.
  34. 34. Schematic diagram of the TEC 6 vaporizer. 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.
  35. 35. Aladin Cassette Vaporizer System ▪ A Novel system ▪ Single vaporizer capable of delivering 5 different anaesthetic agents ▪ It is designed for use with Datex-Ohmeda S/5 ADU and similar machines. ▪ FGF is divided into bypass flow and liquid chamber flow ▪ Liquid chamber flow conducted into agent specific, color coded cassette in which volatile anesthetic is vaporized ▪ Machine accepts only one cassette at a time ▪ Magnetic Labeling
  36. 36. Advantages • Automated recognition of the agent inserted. • On-screen data showing agent levels and anaesthetic usage. • Automated, electronically monitored and controlled FGF, temperature and pressure compensation. • No risk of spillage of anaesthetic agent into the bypass channel. • Cassette can be carried safely in any orientation. Disadvantages • Specific to a particular branded anaesthetic machine. • Anaesthetic delivery requires electrical power.
  37. 37. ▪ 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. DRAGER 19.1
  38. 38. 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.
  39. 39. Safety features ▪ Color specific (for each agent) ▪ Keyed fillers bottles ▪ Low filling port ▪ Vaporizers are locked into the gas circuit, thus ensuring they are seated correctly. ▪ Secured vaporizers Interlocks ▪ less ability to move them about minimizes tipping ▪ Only one vaporizer is turned on ▪ Trace vapor output is minimized when the vaporizer is off ▪ Concentration dial increases output in all when rotated counterclockwise.
  40. 40. Filling system ▪ Bottle Keyed System ▪ Funnel Fill System ▪ Keyed Filling System ▪ Quick-Fill System ▪ Easy-Fill System ▪ Desflurane Filling Systems Quick fill system
  41. 41. FUNNEL FILL ▪ 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.
  42. 42. KEYED FILL 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.
  43. 43. ▪ The bottle has a permanently attached, agent-specific filling device that has three ridges that fit into slots in the filler. QUICK FILL
  44. 44. 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.
  45. 45. Hazards 1. Incorrect Agent 2. Tipping 3. Overfilling 4. Reversed Flow 5. Control Dial in Wrong Position 6. Leaks 7. Vapour Leak into the Fresh Gas Line 8. Contaminants in the Vaporizing Chamber 9. Physical Damage 10. No Vapor Output 11. Projectile
  46. 46. Hazards ▪ Tipping ▪ If tipped >45 degrees-liquid can obstruct the outlet valves ▪ Treatment: Flush for 20-30 min at high flow rates with dial set at high concentration ▪ Overfilling May result in high output ▪ Fill only up to max filling line ▪ Fill only when the vaporizer is off ▪ Leaks ▪ Relatively common due to malposition or loose filler cap. ▪ Not detected with standard checklist perform negative pressure check
  47. 47. Hazards ▪ Misfilling ▪ Vaporizers not equipped with keyed filling lead to misfiling. ▪ Contamination ▪ It occurs by filling a vaporizer with contaminated anesthetic bottle. ▪ Underfilling ▪ Leads to decreased vaporizer output. ▪ Simultaneous Inhaled Anesthetic Administration ▪ Happened in old machines with no interlock system
  48. 48. THANK YOU

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