Intro to Anesthesia machines, Gas supply, cylinders and pipelines ppt Flashcards
the Main integrated anesthesia delivery system includes what?
gas supply
control system
breathing and ventilation system
a scavenging system
What is does the APL valve stand for
Aveolar pressure limiting valve
who are the 3 main anesthesia machine manufactors in the US?
Daxtex-Ohmeda (GE)
North American Draegar (mainly up north)
Datascope
*******the Hospital pipeline is the primary gas source, what is the psig (normal working pressure of most machines)?
50 psig
******Cylinders-O2 is supplied at around 2000 psig. it is regulated to approximately ___ psig after it passes through the downstage regulator into the machine)
45 psig
*******Cylinders are regulated by whom?
The Department of Transportation
**** oxygen flush is a “straight shot” from supply to delivery point at ___ to ___ L/min
35 to 75 L/min
*********************According to the OSHA fact sheet of 1991 on Waste Anesthestic Gasses (WAGs) occupational exposure should be limited to an 8 hour time-weighted average of not more than _______ ppm for halogenated agents such as (Halothane, Enflurane, Isoflurane, Sevoflurane, desflurane)
2 ppm
*********************According to the OSHA fact sheet of 1991 on Waste Anesthestic Gasses (WAGs) occupational exposure should be limited to an 8 hour time-weighted average of not more than_____ppm of halogenated agent is allowed when the halogenated agent is COMBINED with N2O
0.5 ppm
*********************According to the OSHA fact sheet of 1991 on Waste Anesthestic Gasses (WAGs) occupational exposure should be limited to an 8 hour time-weighted average of not more than_______ppm of N2O can be used at all times (with or without halogenated Agent)
25 ppm
******* 5 functions of O2
Powers the ventilators “drive gas”
O2 Flush
Activates low pressure alarms
Activates fail safe mechanisms
Tumbles through the flowmeter
N2O is useful for what?
Assisting with anesthetizing
Air is useful for what?
When N2O won’t do (the few instances when N2O is contraindicated)
this was per his slide I am sure there are other uses since we basically us it for every case as fresh “gas” flows
ORMC stands for what?
Oxygen Ratio Monitor Controller
Can you recite the 4 parts of the path all the way to the pt. (it seems incomplete but this is in his slide)
Hospital medical gas delivery system (large outdoor tanks)
Cylinders
Downstage pressure regulation
intermediate pressure system
Medical gas from the hospital connects to machine using the _________ system??
D.I.S.S.
Cylinders are the ______ pressure source of the medical gasses?
High
The hang in yoke assemblies with the _______ system?
PISS
with the gas inlets and pressure regulators the pressured is measured by the ________ ________ gauges
Bourdon Pressure
What do pressure regulators do? and this is where the what pressure system begins?
reduce the high cylinder pressure to a more manageable 50 psig
This is where the intermediate pressure system begins
*****************
P.I.S.S
what does it stand for?
what is it’s purpose?
Pin-index safety system
it prevents misconnection of a cylinder to the wrong yoke.
you should keep cylinders closed except for what 2 incidences
checking the machine
and In use(if the O2 from the pipeline is unavailable)
The only place you can have high pressure is in the what?
cylinder
*********
since you can only have high pressure in the cylinder it would make sense that all things connected to the system are part of what?
The high pressure system!!
(this will go until something can down regulate it)
since you can only have high pressure in the cylinder it would make sense that all things connected to the system are part of the high pressure system, this system continues until it hits the what?
downstage pressure regulator
4 main parts to the high pressure system
hanger yoke(including filter and unidirectional valve)
Yoke block (with check valves)
cylinder pressure gauge
cylinder pressure regulators
3 Functions of the hanger Yoke
orients cylinders
provides UNIdirectional flow
ensures tight seal at interface
What 3 things does the check valve do?
Minimizes transfilling
allows change of cylinders during use
Minimizes leaks to atm is a yoke is empty
The __________ __________ __________ converts high, variable cylinder pressure to a constant pressure of approximately 45 psig down stream the regulator
cylinder pressure regulator
the cylinder pressure regulator converts high, variable cylinder pressure to 45 psig downstream of the regulator. this is intentionally slightly less than pipeline pressure why?
to prevent silent depletion of cylinder contents if a cylinder is inadvertently left open after checking the pressure
*******
what is special about measuring the amt of N2O in a cylinder
you have to weigh it b/c you can be almost 25% empty and still read 745 psig, there is no way you calculate how much N2O is left in a cylinder without a weight
(so if on a test he gives a formula, and there is no weight, it can’t be done)
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name the Color of the cylinder (US/international), PSIG, Capacity (L), and PISS for
O2
N2O
Air
GAS Color (US/INT) PSIG Capacity (L) PISS
O2 Green (white) 2000 660L 2-5
N2O Blue (blue) 745 1590L 3-5
Air Yellow (B&W) 1900 625L 1-5
a way to remember the PISS
1st they breath air (1-5)
2nd they breathe O2 (2-5)
3rd they breathe N2O (3-5)
(thanks Dwayne)
What 4 things are involved in the Intermediate pressure system
Hospital pipeline outlets
Machine piping
Machine pipeline inlets
Pipeline gauges
the intermediate pressure system receives gasses at a constant pressure of what?
37-55psig
do fail-safe systems pevent hypoxic mixtures???
NO
What does the fail safe device ensure?
the loss of oxygen pressure results in alarms at ____ psig pipeline pressure
- ensures that whenever oxygen pressure reduced and untill flow ceases the set oxygen concentration shall not decrease at the common gas outlet
- 30 psig
As long as there is pressure in the O2 line. nothing in the fail safe system prevents you from turning on a gas mixture of 100% N2O, however this should be prevented by the ________ _______ system
Hypoxic guard
What can cause problems in pipline pressure?
- Contamination (particles, bacteria, viral, moisture)
- inadequate pressure
- excessive pressure
- accidental crossover ( switch b/t oxygen and another gas)
What is you lose pipeline pressure?
- the alarm will sound
- open the O2 cylinder
- Disconect from the wall
*************
How long before a given O2 tank is exhausted
general rules??/
2200psi= 660L
psi * 0.3= L remaining
******************************
The O2 cylinder reads 1000 psi
TFGF is 0.5L/min O2 and 1.5 L/min N2O, RR 10, TV 700
How long till the cylinder is exhausted
Are hypoxic mixtures possiable?
yes
The hypoxic guard system can fail and permit hypoxic breathing mixyures if what occurs
(4)
- wrong suppy gas in O2 pipline or cylinder
- defective pneumatic or mechanical components
- leaks that exist down stream of flow control valves
- if third inert gas is used (helium)
****************
What makes up the low pressure sytem?
(4)
*** everything distal to flowmeter needle valve
- flowmeter tubes
- vaporizers
- check valves (if pressent
- common gas outlet
what is an older term for flowmeters
thorpe tube
what are the components of the flowmeter?
(4)
needle valve
indicator float
knobs
valve stops
Flow increases via the flowmeter when the valve is turned what direction (same as vaporizers)
counterclockwise
At low flows the annular-shaped orfice around the float has what type of flow (according to poiseuille’s law?
what about at high flows?
Low- laminar flow
High- turbulent flow
A hyperbaric chamber produces a ______ than indicated flow on the flowmeter, and anesthesia delivery at higher altitudes produces __________ flows than indicated
- lower
- higher
on the flow meter what is always the last gas in the chain?
O2
why is the O2 always the last gas in the chain (on the flowmeter?
diminishes the chance of hypoxic mixture
decreased chance of O2 dilution
The needle valve of the flowmeter can be damaged if what occure?
it is closed under force
The flow tube (thorpe tube) is shaped how? and specific to what?
Tapered (norrower at bottom)
gas specific
If a valve needle on the flowmeter has 2 tubes, how are they controlled?
a single control
what is the link-25 system? for?
- chain system that connects 2 gasses like O2 and N2O
- the purpose is to decrease the risk of hypoxic mixture delivery-
What are teh restrictions the link 25 system employs?
(4)
- Minimum O2 flow when the machine is on
- minimum O2 / N2O ration (1:3)
- Device or proportioning system that does not allow O2 level < 25%
- hypoxic guard
What is the minimum ration of flow the link 25 system allows b/t O2 and N2O?
1:3
What is Vapor pressure?
when the molecules escape from the volatile liquid to the vapor phase, creating a “saturated vapor pressur” at equilibrium
VP is __________ of Atm pressure
independent
VP __________ with temp increase
Increases
VP depends only on what 2 things
- Physical Characteristics of teh liquid
- it’s temp
how many vaporizers at a given time may be open to the carrier gas?
one
What is included in the circle system?
CO2 absorber housing and absorber
unidirectional valves (AKA fluter Valves)
inspiratory and expiratory ports
fresh gas outlet
APL valve
Pressure Gauge
Breathing tubes
Y-peice
Reservoir bag
Bag/vent switch
Respiratory gas monitor sensor
The CO2 System consist of what? (4)
housing
absorbent
Baffles
Side tube
The CO2 canister consist of
_____% air space
_______% Void Space
________% pore space
50%
42%
8%
All VAA are degraded by absorbents with _____________ exhibiting the highest degradations
Sevoflurane (Ultane)
VAA’s have increased degradations in the CO2 absorber with what 5 things
Baralyme
increased temp
Dry absorber
Duration of exposure
increased anesthetic concentration
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of the 5 things that can increase degradations within the CO2 absorbers what is teh most INFLUENTAL cause? what cause it to occur?
- dry absorbers
- Caused by prolonged high flows
With the bellow assembly the ascending bellows compress _______ during inspiration, and the descending bellows compress _____ during inspiration. this results in a slight negative during exhalation until bellow is refilled
down
up
Teh bellow pressure is always what?
Positive
The bellows cause a PEEP of what
2-4 cmH2O
****************************
The Ascending bellows will collapse in the presence of what?
A leak (disconnect)
