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Flashcards in Anesthesia Machine Deck (56)
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High pressure system

E cylinders: Gas Source: N2O, O2, Air
2000 PSI


Intermediate pressure system

Wall supply
50 PSI


Low pressure system

Flow meters


Basic Function of anesthesia machine

-deliver gases to keep patient alive and asleep
-make sure those gases don't contaminate the air
-means to provide mechanical ventilation
-means to monitor the patient and anesthetic gases


Valve/Regulator function

regulate flow and pressure


Fail-safe valve/device function

prevents hypoxic mixture


Most common type of machine we use at UIHC

-Fabius GS: Children's hosptial
-Narkomed Apollo


GE healthcare AKA?


ASC: S5 Aespire
S5 Aysis: Main OR


SPDD Model

1. Supply: how does gases come to machine?
2. Processing: how does anesthesia gas machine prepare gases before delivery to patient?
3. Delivery: how is the interaction of gases with the patient controlled and monitored?
4. Disposal: how are gases disposed of?


2 main components of anesthesia machine?

1. Electrical System
2. Pneumatic system


Electrical System

1. Master switch (turns on electrical and pneumatic system inside machine, does not need to be on for cylinder pressure to be on)
2. Power failure indicator (visible AND audible)
3. reserve power (back up battery)
4. Electrical outlets (convenience)
5. Data port


Pneumatic system

1. high pressure system
2. intermediate pressure system
3. low pressure system


Electrical sources

1. Single power cord
2. battery backup for 30 minutes
3. convenience outlets (intended for monitors, may not supply electricity if machine is on battery back up)
-do NOT use for heat devices (draw a lot of amperage)


Loss of Machine Electric: Devices NOT reliant on electrical power

Devices NOT reliant on electrical power
-spontaneous/manual assist ventilation
-mechanical flow meters
-variable bypass vaporizers
-aespire: auxiliary flow meters
-monitor with your 5 senses


Loss of machine electric: Devices which require wall outlet electrical power

-mechanical ventilator (will DRAIN back up battery)
-electronic monitors
-digital flowmeter displays for electrical flowmeter
-vaporizers with electronic controls or injection control (des, Saladin cassettes in s/5 ADU)


Pneumatic System: High Pressure

Higher pressure= Cylinder pressure
-hangar yoke (PISS)
-cylinder pressure indicator (gauge)
-pressure regulators
-gas cylinders (E)
-check valves


Pneumatic System: Intermediate Pressure

Intermediate pressure= 37-55 psig
-master switch
-pipeline connections/ pressure indicators
-second stage pressure regulators
-gas power outlet
-oxygen pressure failure devices
-gas selector switch
-oxygen flush
-flow adjustment control
-alternate oxygen flow in case of electrical failure


Pneumatic system: low pressure

Low pressure--- (distal to flowmeter valves)
-hypoxia prevention safety devices
-unidirectional check valves
-pressure relief device
-low pressure piping
-common (fresh) gas outlet
-Alternate (auxiliary) oxygen flow meter
Protects machine from too much pressure **


Pressure regulators

-down regulate pressure so its technically part of high pressure system*********** after this you're in intermediate
-reduced high and variable pressures delivered from the cylinder to more constant usable pressures
-maintains a regular flow rate even as pressure may decrease from the cylinder
-pressure from cylinders are down regulated to less than 50 psi so the machine will get its supply from wall pressure instead of high pressure tanks


Second Stage Pressure Regulators

-each gas be provided with a separate pressure regulator for providing a constant low pressure suitable of rate machine from the variable high pressure cylinders
-some machines use 2 regulators whereby the second regulator delivers the gas at slightly above atmospheric pressure to the downstream components (flow meters)
-helps in providing a smooth constant flow of gas irrespective of fluctuations in pipeline pressure due to peak/trough demands in system


Cylinder Pressure relief valves

-ASTM standards require that all cylinder to have pressure relief devices which vent the contents of the cylinder into the atmosphere should dangerous pressure develop inside the cylinder
-rupture disk: when a determined pressure is reached, a disc guarding an office rupture releasing contents


Check valves

-One way flow valves or unidirectional flow valves
-prevent back flow of gas or permit directional flow
-inspiratory and expiratory valves
-between cylinder sos they don't flow into each other ******


Intermediate Pressure System stops where?

At flow meters= this is beginning of low pressure system


Loss of pipeline (wall) gas

1. Open the emergency oxygen cylinder fully
2. disconnect the wall pipeline connection
-something is wrong with the oxygen pipeline (the oxygen alarm will sound)
-if oxygen analyzer does not warn of the cross over, the pulse oximeter will BUT
3. ALWAYS ventilate by hand*****


Oxygen Safety: Fail safe device

AKA: Oxygen pressure failure device
-WILL NOT let you get hypoxic mixture
-if you lose oxygen supply, N2O will automatically turn off
-any gas coming through system less than 50 PSIG it will reduce your N2O


Ge Aespire Safety Function

-link system device
-a chain links them--- if O2 is turned down then N2O is too


Safety feature of flowmeters

-each knob has different texture


Variable orifice flowmeters

Flow is dependent on:
1. Pressure change across construct
2. Magnitude of annular opening
3. Physical properties of gas: changes in temperature and pressure, density governs flow
Low flow= viscosity governs flow more
High flow= flow > turbulence ?* ask heather


Reading float types:

1. Floats read at top: non-rotating, plumb-bob, skirted, "H"
2. Floats read at middle: ball


Flow meter sequence

1. Oxygen is ALWAYS on the right side- closest to fresh gas outlet
2. Oxygen leak from the flow tube can produce a hypoxic mixture, regardless of arrangement of flow meters*