2. ANESTHESIA MACHINE
• The function of anesthesia
machine is preparation of
anesthesia gas mixture of pure
and precisely known yet
variable composition at
controlled & known pressure.
3. MACHINE STANDARDS
• 1979 – ANSI
• 1988 – ASTM
• Defined
design, performance, safety
requirements of anesthesia
machine.
9. HIGH PRESSURE
• From cylinders to the pressure
regulating valve/ preset valve.
• Convert variable pressure flow
from cylinders to lower and
most constant pressure
suitable for machine
• 760 Psi, 1800 Psi to 40-48 Psi
10. INTERMEDIATE PRESSURE
• Receives gases from pressure
regulating valve or pipeline &
supply to the flowmeters &
oxygen flush valve.
• 40 – 55 Psi from pipeline
• 40 – 48 Psi from pressure
regulating valve
11. LOW PRESSURE
• From flow regulating valve to
common gas outlet.
• Pressure in this system is
slightly above the atmospheric
pressure
• 14 -20 Psi
14. 7PIN INDEX SYSTEM
• machine – pins
• Cylinder – holes
• Pins – 4 mm in dia
• 6mm in length, 12°
• 9/16 inch radius
7 • O2 – 2,5
• N2O - 3,5
• Air – 1,5
• Entonox -7
• Cyclopropane -3,6
15. LIMITATIONS OF PIN
INDEX
• Broken pin
• Upside down yoke block
• Use of double washer
16. HANGER YOKE
ASSEMBLY
• WASHER • FILTER
• GASKET
• Must be present • Acc to ASTM
• Placed around standards.
the nipple
• Only one washer • 100 µm should
• Two nullify pin be installed in
index system between cylinder
• Must be in good & reducing valve
condition
17. CHECK VALVE ASSEMBLY
• One way valve
• Prevent gas leak from empty
yoke
• Allow cylinder change while
using one
• Prevent transfilling of cylinder
• Yoke block, not to keep empty
• cylinder closed – pipeline used.
23. INTERMIDATE
PRESSURE
• LEAK – • GAS POWER
connection OUTLET
inside machine • Supply to
ventilator or jet
• ASTM ventilating system
• PRESSURE < 50
Psi not allowed -
• Leak should not
ventilators will not
be more than 25
function
ml/min at normal
service pressure • Quick coupler
• DISS
24. MASTER SWITCH
• INTERMIDATE
SYSTEM
• Downstream the
inlet
• Oxygen flush will
work even if
standby position
• Sudden turn off is
dangerous
25. OXYGEN PRESSURE
FAILURE DEVICES
• OXYGN FAILURE • OXYGEN
SAFTY – ASTM FAILURE ALARM
• Set pressure o2 • ASTM
conc. should not < • < Set P (30Psi)
19% • Initiated within 5
sec .
• May be silenced
not more than 120
sec.
• Can’t disabled
27. LIMITATIONS
oxygen failure safety
device
• System may be pressured for
weeks if it is gas tight; without
being connected to the oxygen
source.
• Do not offer total protection
against hypoxic mixture
28. QUICK FLUSH SYSTEM
• 35 – 75 lit/min
• 40 - 55 Psi
• Percutaneous
catheter –
adequate
ventilation
• Work even when
master switch off.
• Collar to prevent
accidental
activation.
29. LIMITATIONS OF
OXYGEN FLUSH
• ASTM it should • Flush valve
not increase or sticking in ON
decrease P at position leads to
vaporizer outlet
> 10 KPa • BAROTRAUMA
or output > 20 %
• AWARENESS
• CHECK VALVE
IN MACHINE
30. SECOND STAGE
REDUCING DEVICE
• Just upstream the N2O & O2
control valve.
• Gases from pressure reducing
valve or central supply.
• N2O – 26 Psi
• O2 – 14 Psi
• Flow will be constant below
normal fluctutation range
31. FLOW REGULATING
VALVE
• Touch, placement,
PARTS
color coding.
• Difference with
gases.
• Chemical name
• Link - mechanical,
Pneumatic system
• Pin seat system
• Stop collar
32. PROBLEMS WITH FLOW
CONTROL VALVE
• Inadvertent • Leak through the
alteration - open flow control
Light valve.
touch, accidental
brushing • Failure to allow
adequate gas
• Inability to turn the flow – broken
control knob ON stem blocking the
path.
34. FLOW INDICATER
• Measurement of
the flow of the
gases based on
Lit /min the principle that
when gases
passes through
resistance there
is drop in
pressure
• Drop in pressure
corelated with
flow
36. PHYSICS FLOWMETER
• LOW FLOWS –
• LAMINAR FLOW
VISCOSITY
• HIGH FLOWS
• TURBULANT
• DENSITY
37. FLOW INDICATER
• RATE OF FLOW • PRESSURE DROP
• Pressure drop • Frictional
across constriction resistance float &
• Size of annular tube wall
opening • Turbulent flow
• Physical properties • Drop in energy
of gas • Wt float / cross
sectional area
38. FLOW METER
• Thrope tube
• Narrow at bottom
• Calibrated for gas at
atm. Pressure, 20° C
• Single, dual taper
• Antistatic coating
• Float
• Float rest, stop
• Annular space
• Fluorescent
39. FLOAT OR BOBBIN
• Nonrotating
• Plumb bob, striked
rotating
• Ball
• Indicator of constant
flow
• Important to monitor
• Float stop
• Float rest
• Rib guides
40. PROBLEMS OF
FLOWMETER ASSEMBLY
• FLOWMETER • FLOAT
• Inaccuracy at low • Sudden
flow projection to top
• Calibration with opening of
• Sticking dust cylinder
• Back pressure • Block outlet flow
drops float to • Wrong flow meter
lower position. used.
41. SEQUENCE OF FLOW
INDICATER
• Series – one flow control knob
• Such that delivery of hypoxic
mixture is prevented.
• ASTM – O2 downstream - flow
indicator – near outlet
• Any separate vaporizer flow
indicator should be separated
by at least 10 cm.
42. IMPORTANCE OF
DOWNSTREAM OF O2
• Downstream of
oxygen prevent
hypoxic mixture
going to patient in
case of leak in
the flow indicator
• Safety
mechanism
• Downstream leak
change in
quantity
43. MINIMUM O2 RATIO
DEVICES
• Pneumatic systems
• Mechanical systems
• Alarm systems
• Oxygen ratio monitor controller
& alarm
• Next generation will be
electronic flow measurement
44. OHMEDA LINK 25
SYSTEM
• Pneumatic -
• At least 25% of
oxygen flows in
the system
• One of the
hypoxia guard
• Mechanical-
linkage in O2
N2O knobs by 14
vs 29 tooth
sproket
48. UNIDIRECTIONL CHECK
VALVE
• Unidirectional
check valve
• Between vaporizer
• Positive pressure & common gas
from the breathing outlet
system is
• Upstream of O2
transmitted to
flush flow joins
machine in IPPV &
fresh gas flow
assisted
ventilation&O2 • Gas must flow
flush from flowmeter
• Leak not detected
49. PRESSURE RELIEF
VALVE
• Near the common • Opens at 100 cm
gas outlet of H2O
• To prevent high
pressure from • Limits anesthesia
being transmitted machine to
in to machine deliver jet
• To prevent high ventilation
pressure being
transmitted to Pt • Present in some
from machine machine
50. VAPORIZER MOUNTING
DEVICE
• Located in
between
flowmeter device
and common gas
outlet
• Permanent
mounting
• Change of
vaporizer
51. LOW PRESSURE PIPING
• Large number of connections
• Subject to break or leak
• Flow should not exceed above
30 ml/min at a pressure of
3KPa or 30 cm of water
52. COMMON GAS
OUTLET
• Receives gases & vapors from
the machine
• Outlet in most of the machines
have 15 mm female slip-joint
connection, with coaxial 22 mm
male connection
• Frequent location for leak
53. SAFTY MECHANISMS
• Antistatic coating • Fluorescent back
• Antistatic wheels of flow meter
• Color coding • Master & slaves
• Pin index • O2 failure alarm
• DISS • Oxygen flush
• Pressure guage • Pressure relief
• Touch, coding, pl valve
acement of flow • Unidirectional
regulator check valve
• Rotating bobbin • Trilene interlock
with close system