Anesthesia machine and its safety features with classification of vaporizers and basic boyls machine

1. Presented by- Dr. SHALIMA S
Guides- Dr. NEELAM MEENA
Dr. ABHILASHA THANVI

2.  The original concept of Boyle's
machine was invented by the British
anaesthetist H.E.G. Boyle in 1917
 1920 – A vapourizing bottle is
incorporated to the machine.
 1926 – A 2nd vaporizing bottle and
by-pass controls are incorporated.
 1930 – A Plunger device is added to
the vaporizing bottle.
 1933 – A dry-bobbin type of
flowmeter is introduced.
 1937 – Rotameters displayed dry-
bobbin type of flowmeters

3. 1902: Development of first anaesthetic
apparatus in Germany: hand-held apparatus
145 N, also known as the Roth-Dräger

4. 1910:The Roth-Dräger Mixed
AnaestheticApparatuswas
developed in co-operation with
surgeon friend, Dr Otto Roth

5. 1917: Henry Boyle designs his
first anaesthetic machine.
Boyle's left-handedness lead
to the arrangement of flow
meters and vaporisers that is
still used today. This
original Boyle machine was
improved in a stepwise
fashion between 1920 and
1965.

7. FABIUS GS PREMIUM AESTIVAANAESTHESIA DATEX OHMEDA Drager Apollo

8.  An anesthesia workstation integrates most of the components necessary for
administration of anesthesia into one unit It is a device which delivers a
precisely-known but variable gas mixture, including anaesthetizing and life-
sustaining gases.
 Consists of:
 The anesthesia machine
 Ventilator
 Breathing system
 Scavenging system
 Monitors
 Added to this may be drug delivery systems, suction equipment, and a data
management system
 Standard guidelines have been given to manufacturers for minimum
performance, design, characteristics and safety requirements of machine.
 The current standard for anesthesia workstation as( by American society
for testing and materials) (ASTM) is F1850. European standard is EN740

9. Types of anesthesia machine
Intermittent-Gas flows only during
inspiration
Egs: Entonox apparatus ,Mackessons
apparatus
Continuous-Gas flows both during
inspiration and expiration. Egs :
Boyle Machine
Forregar
Dragger
Ohmeda
Aestiva

10. SYSTEM COMPONENTS
Pneumatic
Electrical
1. Master Switch
2.Power Failure
Indicator
3.Reserve Power
4.Electrical
Outlet 5.Circuit
Breakers 6.Data
Communication
Port
1.High
Pressure
System
2.Intermediate
System 3.Low
Pressure
System

11. Master Switch
Master (main power) switch activates both the pneumatic and electrical
functions . On most machines, when the master switch is in the OFF
position, the only electrical components that are active are the battery
charger and the electrical outlets.
Standby position - allows the system to be powered up quickly. Computer-
driven machines should be turned OFF and restarted with a full checkout
at least every 24 hours.
STANDBY mode is not used for an extended period

12. Power failure indicator
Visual or Audible indicator to alert
provider of power failure

13. • Backup source of power for the occasional outage
is necessary.
• The anesthesia provider should check the battery
status during the preuse checkout procedure.
• While some older anesthesia machines used
replaceable batteries, most new machines use
rechargeable batteries.
• It usually takes a number of hours to fully
recharge a battery after it has completely
discharged.

14. Most modern anesthesia machines have electrical
outlets.
These are intended to power monitors and other
devices.
As a general rule, these outlets should only be
used for anesthesia monitors.
Other appliances should be connected directly to
mains power.
Fig: Next to each outlet is a circuit breaker.

15. • There are circuit breakers for both the anesthesia
machine and the outlets .
• When a circuit breaker is activated, the electrical
load should be reduced and the circuit breaker reset
Data Communication Ports
 Most modern anesthesia machines
have data communications ports.
 These are used to communicate
between the anesthesia machine,
monitors, and the data management
system

16. Pneumatic system
High
Pressure
system Intermediate
Pressure
system
Low
pressure
system

19. 100 kPa = 1000 mbar = 760 mm Hg =
1030 cm H2O = 14.7 psi = 1 atm
1 psi = 6.8 kpa
Psig = pounds per square inch gauge

20. -cylinders

21. • Components:
Body
Valve – Port,
stem
Handle
Pressure
relief
device
Conical
depression
Pin index
safety
system

22.  BODY
Alloy of molybdenum
and steel
MRI – ALUMINIUM
 VALVE
Filled and discharge
through valve
Port : Point of exit
Stem : stem against
seat arrangement to
close valve
body

24. The Hanger yoke assembly
1) Orients and supports the cylinder
2) Provides a gas-tight seal
3) Ensures uni-directional gas flow
The workstation standard recommends that
there be at least one yoke each for oxygen
and nitrous oxide.
If the machine is likely to be used in
locations that do not have piped gases, it is
advisable to have a double yoke,
especially for oxygen.

27.  The check valves are not designed to
act as permanent seals for empty yokes.
 Small amounts of gases can escape if
the yoke is empty or an empty cylinder
(or cylinder with low pressure) and valve
open is present in the yoke.

28.  In order to minimize such losses –
 Yokes should not be left vacant for extended periods
 An empty cylinder should be replaced as soon as
possible , if not then,
 An yoke plug can be used to prevent gas leak or
 An empty cylinder can be left behind after closing the
valve

29.  YOKE PLUG
 Piece of metal
shaped like metal
valve .
 They are also pin
indexed and have
port and conical
depression
 Used to block the
yoke when no
cylinders present.

30.  CONICAL DEPRESSION
Receives retaining screw of the yoke
 PRESSURE RELIEF DEVICE
Venting of contents at dangerously
high pressures
TYPES :
 Rupture disc – copper
 Fusible Plug (Woods alloy) –
bismuth, lead tin, Cadmium
(Melts at 150-170 deg F)
 Combination of both
 Pressure relief valve (spring
loaded)

31.  It is a reclosing
device
 When set
pressure is
exceeded, the
pressure in the
cylinder forces
the spring to open
the channel for
letting out the
gases.

32. PIN INDEX SAFTEY
SYSTEM
Fig :Pin Index Safety System. The bottom figure shows the six
positions for pins on the yoke.
The pins are 4 mm in diameter and 6 mm long, except for pin 7,
which is
slightly thicker.
The seven hole positions are on the circumference of a circle
of 9/16 inch radius centered on the port.

33. -two line one mid-horizontal & other
vertical drawn over the yoke
-meeting point taken as center of gas
inlet hole
-hole is drawn as diameter of 7mm
which is fitted to with BODOKSEAL
-distance between center & lower
part of yoke is 20.6mm.
-from the center a circle is drawn
with a radius of 14.3mm. In that arc
pins numbering 1 to 6 are
positioned.
The pin should be diameter of 4.75
mm & 6mm long

34. oxygen air N2O CO2 nitrogen

35. OXYGEN 2,5
NITROUS OXIDE 3,5
CYCLOPROPANE 3,6
AIR 1,5
NITROGEN 1,4
NITROUS+OXYGEN 7
CARBON DIOXIDE 1,6

36.  A wrong cylinder can be placed in yoke if-
 2 washers are placed on the port.
 Pins on the yoke are broken.
 Holes on the cylinder valve are too deep.

37. -cylinders are fitted with yoke
with a sealing washer called
BODOK SEAL
-it is made up of non
combustible material and has
a metal periphery which
make it long lasting.
-it should be less than 2.4mm
thick
prior to compression.
-only one seal should be use
between the valve & yoke

38. ▫ It is used to open or close a cylinder valve.
▫ It is turned counter-clockwise to open and
clock- wise to close, this causes the stem
to turn.
▫ A good practice is to attach a handle to
each anesthesia machine or other
apparatus for which it may be needed

39. PLACING CYLINDER IN
YOKE.THE CYLINDER IS
SUPPORTED BYTHE FOOT
AND GUIDED INTO PLACE
MANUALLY
 Swinging gate–type
yoke. Note the
washer around the
nipple and the index
pins below.

41.  Labels on the cylinders.
 Pin index system
 Safety relief valve on the cylinder
 Symbols of gases on the cylinder valve
 Color coding .

43. GAS PIN INDEX
AIR 1,5
OXYGEN 2,5
NITROUS OXIDE 3,5
NITROGEN 1,4
O2-CO2 (CO2 <7.5%) 2,6
O2-CO2 (CO2 >7.5%) 1,6
ENTONOX 7

45. 2 COMMONTYPE- 1) BOURDON GAUGE
2) ANEROID GAUGE
Bourdon gauge-
1.It is robust
2.Inexpensive
3.Able to withstand high
pressure
4.Low precision
5.Used to indicate cylinders
and pipeline pressure
Aneroid gauge-
1.Delicate and sensitive
2.Comparatively expensive
3.Able to indicate low
pressure
4.Used for airway & blood
pressure measurement
BOURDON PRESSURE
GAUGE
45

46. 1. The gauge is usually colour coded and name
and symbol of gas are written over the dial.
Blue colour for nitrous oxide and white for
oxygen.
2. Cyclopropane and nitrous oxide does not need
to carry pressure gauge as weight is the only
reliable guide to detect the exact amount in
the cylinder as they are in liquid form.
3. The scale must be at least 33% greater than
the maximum filling pressure of the cylinders
or the full indication position.
4. Gauge is calibrated in (kilopascal)kPa or
(pound per square inch)psi
or Kg/cm2 .
46

49. Light emitting diodes(LED’S)in electronic
pressure gauge indicate
Cylinder valve is close –Dark color
Cylinder valve is open –
Pressure adequate –Green
Pressure inadequate-Red

50.  Converts high variable pressure in cylinders to
constant working pressure suitable for anaesthesia
machine
 The pressure regulators reduce the pressure of the
O2 cylinders from 1900 PSIG to 45-60 PSIG and the
N2O cylinders from 760 PSIG 45-60 PSI

51.  BASIC PRINCIPLE
A larger pressure acting over a small area is
balanced by a smaller pressure acting over a
large area.
a1XP1=A2Xp2

52. PHYSICAL PRINCIPLE
A
P
a
p

53. Pressure reducing valve

54. Begins at the regulated
cylinder supply source
at 45 psig includes the
pipeline sources at 50
to 55 psig and extends
to the flow control
valve.

57.  COMPONENTS
Pneumatic part of the master switch
Pipeline inlet connections
Pipeline pressure indicators
Piping
Gas power outlet
Oxygen pressure failure devices
Oxygen flush
Additional pressure regulators
Flow control valves

58.  Pneumatic part of the master switch
 Located downstream of the inlets for cylinder and
pipeline supply
 Oxygen flush usually independent
 Pipeline inlet connections
 Entry point for gases (O2, N2O, air)
 Unidirectional check valve
 Filter with pore size < 100 µm
 Threaded non interchangeable DISS
Body, Nipple, Nut combinations
Diameters on each part varies so that only properly mated
parts will fit together

59.  DISS

63.  Pipeline pressure
indicators
 Indicates pipeline
pressure of each gas
 50 – 60 psig
 Pipeline side of check
valve
▪ Will monitor pipeline
pressure only
▪ If pipe line fails, cylinder
valve opens and there is
no change in indicator
pressure till cylinder
becomes empty .

64. PIPING
 Previously copper now high density
nylon
 Connects individual components
 Withstand 4 times the intended
service pressure
 Leak between inlet and flowmeter
not more than 25 ml/min
 If yoke and pressure regulator are
included leak not more than 150
ml/min

65.  Gas power outlet (Auxiliary Gas)
 Driving gas for ventilator, gas for jet ventilator
 O2 or air,check valves present.

66. • One or more gas power (auxiliary gas) outlets may be present on an
anesthesia machine. It may serve as the source of driving gas for the
anesthesia ventilator or to supply gas for a jet ventilator. Either oxygen
or air may be used.
• The ventilator is an integral part of the modern machine and the
breathing system and is connected to the ventilator with internal piping.
Therefore, the power outlet is not found in many anesthesia machines
today.

67.  These includes-
 1.Oxygen Failure safety devices- (Oxygen Failure safety
valve,low pressure guardian system, Oxygen Failure
protection devices, pressure sensor shutoff system,fail
safe,nitrous oxide shutoff valve)
 This valve shuts off or proportionally decreases and
ultimately interrupts the supply of nitrous oxide if the
oxygen supply pressure decreases.
 The anaesthesia workstation standard requires that
whenever the oxygen supply pressure reduced below
the manufacturer-specified minimum,the delivered
oxygen concentration shall not decrease below 19% at
the common gas outlet.

68.  O2 Failure Safety
Device (Valve)
 Located in the
intermediate
pressure system
upstream of the
flow control
valves of all
gases except O2
 Shuts off or
proportionally
decreases N2O
SPRING LOADEDVALVE

69. GAS LOADEDVALVE

70.  It depends on pressure not on flow of gases,
machines doesn’t have proportionating system
can still deliver hypoxic mixture.
 Prevent hypoxia due to problems occuring
upstreams of them ...like disconnected oxygen
hose, low pressures in oxygen pipelines , depletion
of oxygen in cylinders.
 Do not prevent hypoxic mixture delivery due to
problems in down streams of these devices....like
crossovers in pipelines, wrong contents in
cylinder , leaks in the equipment, operation errors
like inadvertent closure of oxygen flow meters.

71. 2.Oxygen Supply Failure Alarm-
The anaesthesia workstation standard
specifies that whenever the oxygen supply
pressure falls below the manufacturer-specified
threshold {usually 30psi (205kP)}.
- Alarm shall be enunciated within 5 sec.
- Alarm shall be of at least 7 sec. duration and shall
have a noise level of at least 60dB measured at 1m
from the front of the anaesthetic machine.
- They add in preventing hypoxia caused by problems
occurring in the machine circuit.
- Equipment problems(leaks) or operators error
(closed or partially closed flow control valve) occur
downstream are not prevented by these devices.
71

72.  Secondary Pressure
Regulators:
 Machine working pressure
may fluctuate. Eg: At times
of Peak demand.
 Parallel fluctuations in
flowmeter performance
 Pressure regulator set below
the anticipated pressure
drop smoothes out the
supply.
 Mechanically linked anti
hypoxia device assume
oxygen pressure to be
constant
 26 psig for N2O
 14 psig for O2

75.  The flow adjustment controls regulate the flow of
oxygen, air, and other gases to the flow indicators.
 There are two types of flow adjustment controls:
mechanical and electronic.
 The anesthesia workstation standard requires that there
be only one flow control for each gas. It must be
adjacent to or identifiable with its associated flowmeter.

76. Flow Control Knobs

77.  To eliminate any looseness in the threads, the valve may be spring loaded.
This also minimizes flow fluctuations from lateral or axial pressure applied
to the flow control knob.

78.  It is advantageous to have stops for the OFF and MAXIMUM
flow positions. A stop for the OFF position avoids damage
to the valve seat. A stop for the MAXIMUM flow position
prevents the stem from becoming disengaged from the
body.
 Control Knob :
The control knob is joined to the stem. If it is a rotary style
knob, the oxygen flow control knob must have a fluted
profile and be as large as or larger than that for any other
gas. All other flow control knobs must be round. The knob
is turned counterclockwise to increase flow. If Other types
of flow control valves are present, the oxygen control must
look and feel different from the other controls.

80.  When a machine is not being used, the gas source
(cylinder or pipeline) should be closed or disconnected.
 The flow control valves should be opened until the gas
pressure is reduced to zero and then closed.
 If the gas source is not disconnected, the flow control
valve should be turned OFF to avoid the fresh gas
desiccating the carbon dioxide absorbent and to
conserve gas.
 Before machine use is resumed, the control valves
should be checked to make certain that they are closed.
 Sometimes, a flow control valve remains open after the
gas is bled out or opened when the machine is cleaned
or moved.
 If the gas supply to an open flow control valve is
restored and the associated flow indicator is not
observed, the indicator may rise to the top of the tube
where its presence may not be noticed.
 Even if no harm to the patient results, the sudden rise
may damage it and impair the flow meter accuracy.

82.  Flowmeter
Assembly
 Tube,
indicator,
stop, scale,
 Empties into a
common
manifold

84.  Tube
 Glass
(pyrex)
 Single /
Double
taper
 Rib guides
for ball
indicator SINGLE TAPER DUAL TAPER

86.  Indicator
 Free moving
device
 Made of
aluminium
 Nonrotating
 Rotating –
grooves,
colored dot.
 Ball – rib
guides,
rotates.

90.  Prefer digital system
 Solenoid valves
 Control flow on or off
valves
 Computer controlled
 .

92.  Flowmeters
 Size of annular
opening
Increase in flow
causes an
increase in the
size of the
opening

96.  Flowmeter tube arrangement
SAFE

97.  An oxygen leak from the flow tube can
produce a hypoxic mixture, regardless of the
arrangement of the flow tubes

98.  ANTI HYPOXIA DEVICES
 Mechanical device : Link 25
system
 Pneumatic device : Oxygen Ratio
Monitor
Controller (ORMC)
 Electronically controlled : Penlon
Ltd

102.  .

103.  Pneumatic devices
 Oxygen Ratio Monitor Controller
(ORMC) (Drager)
 Depend on the balance of
pressure exerted by O2 & N2O on
a coupled diaphragm
 Nitrous oxide slave control valve

105.  Electronically controlled anti
hypoxia device
 in penlon machines there is
aParamagnetic O2 Analyzer
 Whenever oxygen concentration
less than 25% there is an audible
alarm and nitrous oxide supply
cuts off.

106.  Linear resistors [3:1 ratio for
N2O & O2)between O2
andN2O flow control valves.
 Ensure 25% O2 by limiting
N2O flow.
 ORMC shuts off N2O if ratio
of O2 flow falls below 30%
 S-ORC-newest hypoxic guard
. installed in Fabius-GS by
Drager.ensures aFiO2 of
23%. O2 flow <200ml/min.
 .

107.  Anti hypoxic device may also deliver hypoxic
mixture under following conditions-
 Wrong supply of gas.
 Defective pneumatics/mechanics.
 Inert gas administration(3rd gas-He,N2,CO2).
 Leaks downstream.

114. BACK BAR
POP OFF
VALVE

118.  Antistatic large castor wheels:
360 rotation
 Front wheel locking bar
 Small floor space 83 cm X 67 cm
 Colour coded cylinders
 Provision to accommodate 2 type
E cylinders
 High pressure gas conduit tubing

119.  Pin index system
 Pressure gauges
 Pressure reducing valves
 Oxygen fail safe device
 Low pressure alarms
 2 auxillary oxygen outlets

120.  Flow meters:
▪ Flow control valves, colour and touch coded
▪ Oxygen knob; large, stands out
▪ Minimium distance between knobs 25 mm
▪ Recessed, guarded, bar protected knobs
▪ Minimum 90 rotation required to change setting
▪ Base rest for the bobbin
▪ Rotating bobbin (slanted grooves/cuts at the top)
▪ Long tubes, easy and accurate setting of flow

121.  Flow meters:
▪ Gas specific colour coded bobbin
▪ Flouroscent dot on the bobbin
▪ Position of the tubing
▪ Top stop spring loaded
▪ Arrangement of flowmeters, O2 flowmeter
downstream
▪ Antistatic lumen of the tubes (tin oxide coating)
▪ Back plate flouroscent

122.  Non-return pop-off valve
 Trilene lock (Boyle F)
 Antistatic tubing, bag and mask
 Oxygen flush device
 Vaporiser arrangement (boiling
pt, potency)
 Colour coded vaporisers
 Keyed filling ports of vaporisers

123. 123

124.  First checklist – 1987
 Revised in 1993.
 Latest revision in 2008
 Principle based as no one checklist applies to all modern
machine models

125. 1. Verify backup ventilation
equipment is available &
functioning.
 Contaminated oxygen supply,
 Loss of oxygen supply pressure
 Obstruction of the breathing
system
So check for that Ambu!

126. 2. Check oxygen cylinder supply
 1 cylinder atleast half full (1000
psi)
 Not necessary to check N2O
 Close cylinder after checking

127. 3. Check central pipeline supplies.
 Check for proper connection at
wall
 Check the pipeline pressure
gauge- should read approximately
50 psi.

128. 4. Check initial status of low
pressure system.
 Check liquid level and fill
vaporizers if necessary
 Fill ports tightly capped.
 Check vaporizer interlock.

129. 5. Perform leak check of low
pressure system.
 Leaks as low as 100 mL/min
may lead to critical decrease in
the concentration of volatile
anesthetic (creating a risk for
intraoperative awareness), or
permit hypoxic mixtures under
certain circumstances.
 Negative pressure leak test (10
sec.) is recommended.
 Repeat for each vaporizer.

130. 6. Turn master switch on.
7. Test flowmeters.
Damage
Full range
Hypoxic guard.

131. 8. Calibrate oxygen monitor
 Final line of defense against
hypoxic mixtures.
 Calibrate/daily check: Expose to
room air and allow to equilibrate
(2 min). Then expose to oxygen
source and ensure it reads near
100%

132. 9. Check initial status of breathing system
 Set the selector switch to Bag mode.
 Check that the breathing circuit is
complete, undamaged, and
unobstructed.
 Verify that the carbon dioxide absorbent
is adequate.
 Install the breathing circuit accessory
equipment (e.g., humidifier, PEEP valve)
to be used during the case

133. 10. Test Ventilation systems and
unidirectional valves
 Test ventilator – Bag on Y piece-
look for adequate tidal volume,
filling of bellows at minimal flows.
 Check proper action of
unidirectional valves.

134. 11. Perform leak test of breathing system
 High pressure leak test : Pressurise
breathing system to 30 cm H2O  10
seconds
 Open APL  pressure must decrease
 Bains : Inspection
Inner tube occlusion test
O2 flush test – Venturi effect

135. 12. Adjust and check scavenging system.
 Ensure proper connections between the
scavenging system and both the adjustable
pressure limiting (APL) (pop-off) valve and the
ventilator's relief valve.
 Adjust the waste gas vacuum (if possible).
 Fully open the APL valve and occlude the Y-
piece.
 With minimum O2 flow, allow the scavenger
reservoir bag to collapse completely, and
verify that the absorber pressure gauge
reads about zero.
 With the O2 flush activated, allow the
scavenger reservoir bag to distend fully,
and then verify that absorber pressure
gauge reads <10 cm H2 O.

136. 13. Check, calibrate, set alarm
limits of all monitors
 Capnometer
 Oxygen analyzer
 Pressure monitor with alarms for
high and low airway pressure
 Pulse oximeter
 Respiratory volume monitor (i.e.,
spirometer)

137. 14. Check final status of machine
 Vaporizers off
 Bag/Vent switch to "bag" mode
 APL open
 Zero flows on flowmeters
 Suction adequate
 Breathing system ready

138. 15. “Anesthesia Time Out” – To be
checked immediately before
induction :
 All monitors attached, functional?
 Capnogram, SpO2 waveforms?
 Flowmeter, vent settings proper?
 Manual/vent switch to manual and
APL open?
 Vaporizers filled?

142. Repeat Check before each patient:
 Suction
▪Absorbent
▪Vaporizers
Breathing circuit
Monitors/alarms
Anesthesia time out

143.  Minimum test under life-threatening
conditions
1. High pressure test of the breathing
circuit
2. Check patient suction
3. Observe and/or palpate breathing bag
during preoxygenation.
 This ensures adequate flow of oxygen
 Good mask fit (very important)
 The patient is breathing
 The Bag/Vent switch is on "Bag" not "Vent"
Checklist can be bypassed only a limited number of times