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1. Speaker : Dr Omar Kamal

2.  To safeguard human life from unknown
human errors.
 Safety devices are to prevent delivery of
hypoxic mixture
 Regulation to prevent excessive pressure which
is traumatic to patient

3.  1979: American National Standards Institute
(ANSI)
 1988: American Society for Testing and
Materials (ASTM) F1161-883
 1994: ASTM F1161-944 (reapproved in 1994 and
discontinued in 2000)
 2000: ASTM F1850-005

4. 2000 ASTM F1850-00 standard, newly
 continuous breathing system pressure,
 exhaled tidal volume, ventilatory CO2
concentration,
 anesthetic vapor concentration, inspired
oxygen concentration,
 oxygen supply pressure, arterial oxygen
saturation of hemoglobin,
 arterial blood pressure, and continuous
electrocardiogram

5.  Master Switch
 Power Failure Indicator
 Reserve Power
 Electrical Outlets
 Circuit Breakers
 Data Communication Ports

6.  High pressure division
 Intermediate pressure division
 Low pressure division

8.  Gas cylinder
Color coding
Cylinder labels
Symbol of gas
Pin index safety system
Safety relief device
Filling within service pressure

9. Oxygen black body,white shoulders
Nitrous oxide blue
Air white and black
Carbon dioxide gray
Helium brown
Entonox black with blue/white shoulders

14.  The safety relief device is composed of atleast
one of
- Frangible disc [bursts under extreme
pressure]
- Fusible plug [wood’s metal which has
a low melting Point ]
- Safety relief valve [ opens at extreme
pressure ]

15.  Check valves at the cylinder inlet and pipeline
inlet
 Cylinder pressure indicator [ bourdon’ s
pressure gauge]
 Pressure regulator
 Pressure relief valves
 Washer [ bodok seal ] – rubber made of
neoprene

16.  Gauge is usually color coded.
 Name and symbol of gas are written over dial.
 If bourdon tube ruptures gas is vented from
back side
 Gauges are angled and placed in such a way
that it can be easily read by anesthetist.
 Instructions like “use no oil’’ “open the valve
slowly’’ are written on the gauge

18.  Pressure regulators have safety relief valves
 Safety valve blow off at a set pressure of 525 k
pa(70psi)

19.  Pipeline
• wall outlet : labelled and colour coded
• primary valve or automatic shut off valve
• secondary valve or isolation valve
• schraeders probes, quick connectors or
diameter index safety system to prevent
interchangeability
• pipeline hoses – colour coded

20. The 2000 ASTM F1850-00 standard states that
“The anesthesia gas supply device shall be
designed so that whenever oxygen supply
pressure is reduced to below the manufacturer
specified minimum, the delivered oxygen
concentration shall not decrease below 19% at the
common gas outlet.”

21. fail-safe valve
 is located downstream from the nitrous oxide
supply source.
 This valve shuts off or proportionally
decreases the supply of nitrous oxide (and
other gases) if the oxygen supply pressure
declines

23.  Datex-Ohmeda machines
 Threshold principle
 This valve operates in a threshold manner and
is either open or closed.
 Oxygen supply pressure opens the valve, and
the valve return spring closes the valve

25.  OFPD is based on a proportioning principle
 The pressure of all gases controlled by the
OFPD will decrease proportionally with the
oxygen pressure.
 consists of a seat nozzle assembly connected to
a spring-loaded piston

26.  The oxygen flow control knob is distinctively
fluted, projects beyond the control knobs of the
other gases, and is larger in diameter
 All knobs are color-coded for the appropriate
gas,
 the chemical formula or name of the gas is
permanently marked on each.
 If a single gas has two flow tubes, the tubes are
arranged in series and controlled by a single
flow control valve.

27. - Bobbin rotates on flow which prevents it
from sticking.
- Antistatic spray in flowmeter
- master and slave safety mechanism for gas delivery
between N2O and O2
- Downstream placement of oxygen flowmeter
- Radio florescent plastic sheet behind flow meter
- Float stop
- Auxiliary oxygen flowmeter

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

31.  Proportionating devices –
• link 25 in datex
ohmeda[mechanical,pneumatic
and electronic linkage]
• S-ORC( sensitive oxygen ratio controller)
ORMC( oxygen ratio monitor controller) in
draeger,
• Mandatory minimum oxygen flow :
150 to 250 ml/min

33.  It allows independent adjustment of either
valve, automatically intercedes to maintain a
minimum 25% oxygen concentration with a
maximum N2O– oxygen flow ratio of 3 : 1
 increases oxygen flow to prevent delivery of a
hypoxic mixture.
 14-tooth sprocket (nitrous oxide flow control
valve) , 28-tooth sprocket (oxygen flow control
valve)
 2 : 1 gear ratio

35.  Pneumatic oxygen–nitrous oxide interlock
systems designed to maintain a fresh gas
oxygen concentration of at least 25%
 ORMC and S-ORC limit nitrous oxide flow to
prevent delivery of a hypoxic mixture

36.  Movement of the shaft regulates the nitrous
oxide slave control valve, which feeds the
nitrous oxide flow control valve.
 If the oxygen pressure > N2O , the nitrous
oxide slave control valve opens wider to allow
more nitrous oxide to flow.
 As the N2O flow is increased manually, this
pressure forces the shaft toward the oxygen
chamber limiting the flow of N2O

37.  whenever the oxygen supply pressure falls
below a manufacturer-specified threshold
(usually 30 psig (205 kPa)
 at least a medium priority alarm shall be
enunciated within 5 seconds
Limitations
 Depend on pressure and not flow
 Do not prevent anesthetic gas from flowing if
there is no flow of oxygen
 Crossovers in the pipeline system or a cylinder
containing the wrong gas
 Leaks downstream

38. Ritchie whistle
 Present in older machines – ohmeda
 When the oxygen pressure drops below 260
kpa( 38 psi ), oxygen failure whistle valve
opens
 Whistle sounds continuously, until oxygen
pressure has fallen to approx 40.5 kpa ( 6 psi )
 At 30 psi ( 200 kpa ) , it cuts off the supply of
anesthetic gases to the patient

39. Criteria required for oxygen failure warning
devices :
 Alarm should be auditory(60 dB), for atleast 7
s duration measured at 1 m..
 alarm gets activated when oxygen supply
pressure falls to approx 200 kpa
 Alarm linked to gas shut off device

40.  Vaporizers - Interlocking Selectatec
mechanism, low filling port..
 Unidirectional [check ] valve
 Back pressure relief valve [opens when the
pressure exceeds 200 cm H2O]
 Common gas outlet

41.  Receives oxygen from the pipeline inlet or cylinder
pressure regulator and directs a high unmetered
flow directly to the common gas outlet
 labeled “O2+.”
 activated regardless of whether the master switch is
turned ON or OFF.
 flow between 35 and 75 L/minute delivered
 The button is commonly recessed or placed in a
collar to prevent accidental activation
 activation does not increase or decrease the pressure
at the vaporizer outlet > 10 kPa or increase the vapor
output > 20%

43. Limitations
 Accidental activation and internal leakage
 The flush valve may stick in the ON position
 Oxygen flush activation during inspiration -
barotrauma

44.  Its purpose is to prevent backflow into the
vaporizer during positive-pressure ventilation,
thereby minimizing the effects of intermittent
fluctuations in downstream pressure on the
concentration of inhaled anesthetic

45.  APL valve open when pressure exceeds 60 cm
H2O
 Pressure in reservoir bag shouldn’t exceed 60
cm H2O.
 Oxygen analyser
 Canister – Dessicated absorbents without KOH
or ba(OH)2 and with lesser amounts of NaOH
produce less heat and no fires

46.  VENTILATORS – Pressure sensors to detect
excessive airway pressure due to ventilator
malfunction
 Alternative oxygen control
 Scavenging system
 Wheels in anesthetic workstation is made of
antistatic low friction rubber.

47.  More accurate and corrected tidal volume
through compliance and fresh gas
compensation
 Fresh gas decoupling prevent hyperinflation of
the lung
 Electronic PEEP
 Electronic selection of ventilation parameters
 Reduced external connections

48.  It is the only machine safety device that
evaluates the integrity of the low-pressure
circuit
 Oxygen concentration–sensing element must
be exposed to room air for calibration to 21%.

49. Absolute criteria:
1. Lack of essential safety features such as:
A. O2/N2O proportioning system
B. O2 failure safety device (‘‘fail--safe’’ system)
C. O2 supply failure alarm
D. vaporizer interlock device
E. noninterchangeable, gas-specific pin indexed and
diameter-indexed safety systems for gas supplies.

50. 1. Presence of unacceptable features such as:
A. measured flow vaporizers (e.g., Copper Kettle)
B. more than one flow control knob for a single gas
delivered to the common gas outlet
C. vaporizer with a dial such that the concentration
increases when the dial is turned clockwise
D. connections in the scavenging system that are the
same (15 or 22mm diameter) as in the breathing
system.
2. Adequate maintenance no longer possible

51. 1. Lack of certain safety features such as
A. a manual/automatic bag/ventilator selector switch
B. a fluted O2 flow-control knob that is larger than the
other gas flow-control knobs
C. an O2 flush control that is protected from unintentional
activation
D. an antidisconnection device at the common gas outlet
E. an airway pressure alarm.
2. Problems with maintenance.
3. Potential for human error.
4. Inability to meet practice needs such as
A. accepting vaporizers for newer agents
B. ability to deliver low fresh gas flows (FGFs)
C. a ventilator that is not capable of safely ventilating the
lungs of the target patient population

57. THANK YOU