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184 Cards in this Set

  • Front
  • Back
The Electric System [5]
Master switch
Power failure Indicator
Backup power (battery)
Electric outlets
Circuit breakers
Floating (check) valve:
Move whichever way pressure is pushing.
Diaphragm valve:
Turning the stem raises or lowers the flexible diaphragm and seals the opening to internal parts.
Flutter valve:
Inspiration/Expiration check valves, unidirectional
Flow control (needle/pin/fine adjustment/flow adjustment) valve:
Controls the rate of flow of a gas through its associated flow indicator by manual adjustment of a variable orifice. One/gas.
APL (pop of):
Adjustable pressure limiting valve. Adjustable knob and mechanism with spring control placement of diaphragm in valve seat to regulate how much anesthesia gas enters into gas scavenging system.
Spring disc (ball) valve:
A spring holds the disc against the seat. When pressure on the disc is great enough to overcome the force of the spring, the valve opens. Flush valve, all or none.
Check Valves: 3 main functions
1) Prevents “back-flow” from high-pressure to low-pressure sides; prevents “pumping action” of gases. Pumping action is generated by positive pressure ventilation or by intermittent pressing and releasing of the O2 flush valve, especially when running low flows, the net result was an increased concentration of anesthetic being delivered. New vaporizers have a decreased size of vaporizing chamber and an increased volume in the inflow channel.

2) Allows for an empty cylinder to be exchanged for a full one with minimal loss of gas

3) Minimizes leakage from an open cylinder to the atmosphere
The Pneumatic System
3 Systems
High Pressure

Intermediate Pressure

Low Pressure
High Pressure System

Hanger Yoke
Body, Filter
Retaining screw
Index pins on yoke
Check valves in hanger yoke
Check valve assembly
Cylinder pressure gauges
High Pressure System[4]
Hanger yoke
Cylinder Pressure Indicator (gauge)
Pressure-reducing device (regulator), 1st stage, diaphragm valve
Woods metal: bows with high heat (200 C.) to let gas out slowly
Intermediate Pressure System [10]
Pipeline inlet connections
Pipeline pressure Indicators/gauges
Gas power outlet
Master switch (pneumatic component)
Flush valve
2nd stage regulator, psig 40-50 drops to 16 psig
“Fail safe” shut off valve
DISS: diameter indexed safety system
Flow control valve of manifold has the greatest fluctuation in pressure
Intermediate Pressure System

DISS: Diameter Indexed Safety System [6]
1) Quick push-on connectors
2) indexed for a specific gas
3) 40-50 ppsi for O2/N2O
4) Check valve in pipeline inlet assembly is a floating valve and seats according to pressure
5) On back of gas machine
6) Power outlet valve is ball & spring valve
02 tank

Hanger Yolk Valve: [4]
1) In yolk assembly and has pins for E cylinders to fit on. The O2 pin index is 2,5 & N2O is 3,5
2) Acts as a safety valve
3) Opens/closes with pressure,
“free floating valve”
4) Prevents a full cylinder from emptying into an empty cylinder and from wall oxygen from entering a cylinder
02 tank

Oxygen cylinder pressure regulator (first stage regulator) [3]
1) Cylinder pressure decreased to 40-50 ppsi
2) Serves both yolks
3) This is a diaphragm valve
Intermediate Pressure System functions [3]
1) Check valve between vaporizer outlet and machine outlet (not present on all machines)
Prevents reversal of flow
Diaphragm type valve (stifffer)
2) Inspiration and Expiration valve (flutter valves)
3) Permits direction of gas flow to and from the patient
- Opening is limited by a retainer
Intermediate Pressure System

Oxygen flow meter and flow control valve
Deliver gas to patient circuit
Receives low pressure gas (16 psi)Oxygen flow meter and flow control valve
Deliver gas to patient circuit
Receives low pressure gas (16 psi)
Needle valve
The thorpe tube is gas specific and tapered with largest diameter at the top
Intermediate Pressure System
\Oxygen pressure failure devices (Oxygen failure safety device)
Senses oxygen pressure at 50 psi
Shuts off N2O
O2 must maintain at least 25 psi on the diaphragm to keep the valve open
Pin and spring valve
Senses pressure only, not flow delivery
Fluted knobs
Intermediate Pressure System

Oxygen supply failure alarm
Electronic alarms
Pneumatic alarms
Intermediate Pressure System

Oxygen flush valve;
O2 is delivered directly to the patient at a rate of 35-75 l/min. This will dilute the anesthetic gases. Can cause barotrauma.
Intermediate Pressure System

Gas selector switch:
bag vs. ventilator
Intermediate Pressure System

Second-stage-reducing device:
reduces line pressure and maintains constant flow with changing supply pressures
Intermediate Pressure System

-Flow control valves
components [3]
-Flow control valves
a) Body
b) Stem and seat
c) Control knob
Intermediate Pressure System

-Problems with flow control valves
a) Inadvertent alterations
b) Inability to turn control knob
c) Leak through open flow control valve
d) Failure to allow adequate gas flow
Low Pressure System components [3] [5]
1) Vaporizer
2) Common gas oputlet
3) Manifol and check valves, fluctuates the least

Unidirectional (check) valve
Pressure relief device
Low-pressure piping
Vaporizer mounting devices
Common (fresh) gas outlet
Low Pressure System

Flow indicators
Physical principles
A) Flow indicators
1) Physical principles
Pressure drop across the constriction
Size of the annular opening
Physical characteristics of the gas
Temperature and pressure effects
Low Pressure System

Flow indicator blocks
Nonrotating floats
Ball floats
Arrangement of flow indicator tubes
Sequence of flow indicator tubes
Safety devices
Mandatory minimum oxygen flow
Minimum oxygen ratio device
Mechanical linkage
Pneumatic linkage
Low Pressure System

Problems with flow indicators/thorpe tube
- Improper assembly or calibration
- Sticking Indicator, large on top, small on bottom
- Back pressure
Problems with the float
Indicator unnoticed at top of tube
Blockage of tube outlet
Reading of wrong flow indicator
Changes in float position
Using the wrong flowmeter
APL Valve (pop off)
Adjusts the limit of pressure in the patient circuit and rebreathing bag
2) Tightening the knob will increase the pressure
3) Attached to exhalation check valve
Machine Check

Nine parameters that the anesthesia machine must monitor in order to be in federal compliance
1) Continuous breathing system pressure
2) Exhaled tidal volume
3) Ventilatory CO2 concentration
4) Anesthetic vapor concentration
5) Inspired O2 concentration
6) Arterial oxygen concentration
7) Oxygen supply pressure
8) Arterial blood pressure
9) Continuous EKG
High pressure system check
2) Check oxygen cylinder supply
a) open O2 cylinder and verify at least half full (about 1000psi),
close cylinder
3) Check central pipeline supplies
a) check that hoses are connected and pipeline gauges read about 50 psi
Low pressure system check
Check initial status of low pressure system
a) Close flow control valves and turn vaporizers off
b) Check fill level and tighten vaporizers’ filler caps
Perform leak check of machine low pressure system
a) Verify that the machine master switch and flow control valves are off
b) Attach “suction bulb” to common (fresh) gas outlet
c) Squeeze bulb repeatedly until fully collapsed
d) Verify bulb stays fully collapsed for at >10 seconds
e) Open 1 vaporizer at a time and repeat c and d above
f) Remove suction bulb, and reconnect fresh gas hose
Test flowmeters
a) Adjust flow of all gases through their full range, checking for smooth operation of floats and undamaged flowtubes
b) Attempt to create a hypoxic O2/NO2 mixture and verify correct changes in flow and/or alarm
Scavenging system check

Adjust and check scavenging system
a) Ensure proper connections between the scavenging system and both APL (pop-off) valve and ventilator relief valve
b) Adjust waste gas vacuum (if possible)
c) Fully open APL valve and occlude Y-piece
d) With minimum O2 flow, allow scavenger reservoir bag to collapse completely and verify that absorber pressure gauge reads about zero
e) With the O2 flush activated, allow the scavenger reservoir bag to distend fully, and then verify that absorber gauge reads <10cm H2O
Breathing system check
9) Calibrate O2 monitor
a) Ensure monitor reads 21% in room air
b) Verify low O2 alarm is enabled and functioning
c) Reinstall sensor in circuit and flush breathing system with O2
d) Verify that monitor now reads greater than 90%
10) Check initial status of breathing system
a) Set selector switch to “Bag” mode
b) Check that breathing circuit is complete, undamaged and unobstructed
c) Verify that CO2 absorbent is adequate
d) Install breathing circuit accessory equipment (ie. Humidifier, PEEP valve) to be used during the case

11) Perform leak check of breathing system
a) Set all gas flows to zero (or minimum)
b) Close APL (pop-off) valve and occlude Y-piece
c) Pressurize breathing system to about 30 cm H2O with O2 flush
d) Ensure that pressure remains fixed for at least 10 seconds
e) Open APL (pop-off) valve and ensure that pressure decreases
Manual and automatic ventilation systems check
Test ventilation systems and unidirectional valves
a) Place a second breathing bag on Y-piece
b) Set appropriate ventilator parameters for next patient
c) Switch to automatic ventilation (Ventilator mode)
d) Turn ventilator ON and fill bellows & breathing bag with O2 flush
e) Set O2 flow to minimum, other gas flows to zero
f) Verify that during inspiration bellows delivers appropriate tidal volume and that during expiration bellows fill completely
g) Set fresh gas flow to about 5L/min
h) Verify that the ventilator bellows and simulated lungs fill and empty appropriately without sustained pressure at end expiration
i) Check for proper action of unidirectional valves
j) Exercise breathing circuit accessories to ensure proper function
k)Turn ventilator OFF and switch to manual ventilation (Bag/APL) mode
l) Ventilate manually and assure inflation and deflation of artificial lungs and appropriate feel of system resistance and compliance
m) Remove second breathing bag from Y-piece
Monitors check
13) Check, calibrate and/or set alarm limits of all monitors
-Capnometer -Oxygen analyzer
-Pressure monitor with -Respiratory volume
high and low airway alarms monitor (spirometer)
Final position check
Final position
14) Check final status of machine
a) Vaporizers off
b) APL valve
c) Selector switch to “Bag”
d) All flowmeters to zero
e) Patient suction level adequate
f) Breathing system ready to use
CO2 Absorbant
Function: makes rebreathing possible, thus conserving gases and volatile agents, decreasing OR pollution, and avoiding hazards of CO2 re-breathing
Soda lime-Activator: NaOH or KOH. Silica and kieselguhr added as hardeners
Indicators for Sodasorb are colorless when fresh, and purple when exhausted because of pH changes in the granules
Gas flows downward
CO2 Absorbant...more
1) When soda lime is exhausted, the granules do not crumble
2) 1500cc canister holds a tidal volume of 750cc
3) Mesh size is 4x8, granules will fall through a screen with 4 wires/1 inch, but not through a screen with 8 wires/1 inch
4) A total obstruction of the circle system occurs if the clear plastic shipping wrapper is not removed from the CO2 canister before use
To change canisters:
1) Wear gloves
2) Loosen clamp
3) Remove and discard top canister
4) Promote the bottom canister to the top and put the fresh canister on the bottom
5) Check for circuit leaks
6) Always remove wrap before inserting canister
7) Don’t change mid-case; convert to semi-open circuit by increasing FGF to >5L/min
Expired gas monitoring
The most common type of monitor is sidestream. In this case a connector is placed in the circuit which is connedted to a small bore tubing (gas sampling line) that is then connected to the gas inlet of the monitor. A sample of gas from the breathing circuit is continuously collected by the monitor and measured.
Compressed Gas Cylinders
Steel tanks 3/8 inch thick, some are chrome alloy
Pressure tested to 5/3 their serve pressure
Subject to a test by interior hydrostatic pressure at least once/5 years
Compressed gas cylinders Standards
1) Interstate Commerce Commission: gas cylinder construction
2) Federal Food, Drug, and Cosmetic Act: regulates the medical gases contained in cylinders
3) United States pharmacopeia: regulates potency and purity
4) Department of Transportation: design, construction, testing, marking, labeling, filling, storage, handling, maintenance, and transportation
5) Compressed Gas Association: standards of safe practice. Has no legal force, but compliance is basis for accreditation by JCAHO
6) National Fire Prevention Associaion: same as CGA, recommendations for the location, construction, and installation of bulk oxygen systems
7) American National Standards Institute: sets down basic performance and safety requirements for components of anesthesia machines, endotracheal tubes, connections, pressure and vacuum, and gas pressure regulators
8) National Institute for Occupational Safety and Health Act: standards to protect the health and safety of workers
9) Food and Drug Administration: makes standards for medical devices and gases
10) American Society for Testing Materials: assess technology and revise standards
11) Joint Commission on Accreditation of Healthcare Organizations: voluntary accrediting agency
12) Pharmacopoeia of the US: develops purity spec’s for gases
13) National Formulary: developed purity spec’s for gases
Compressed gas cylinders
Labeling and Marking
A) All cylinders must be marked according to ICC regulations. The lettering must be _” high
B) 7 markings must be on the cylinder
1) Regulatory body (DOT), type/material of cylinder
2) Serial number
3) Purchaser, user, manufacturer
4) Manufacturer’s identifying symbol
5) Manufacturer’s manual
6) Retest date, re-tester, ID symbol, 110% filling, 10 year test
7) Neck ring owners identification
Critical temperature:
the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied.
Critical pressure:
the pressure required to liquefy a gas at its critical temperature


1900 (full)


1900 (full)
Withdrawing cylinder contents:
1) The cylinder should be opened slightly for a moment to clear the outlet of possible dust. This called cracking the cylinder.
2) The adiabatic heat of compression can generate heat and cause ignition. The compression of cylinder content into a smaller space generates the heat that may cause combustion.
3) Each valve stem on the cylinder has a safety device which under hazardous conditions of excessive heat or fire will cause the cylinder to become exhausted. This safety device is a simple plug of soft metal alloy called Wood’s Metal; it is composted of bismuth, lead, tin, and cadmium. This plug will melt at 200 degrees F.
a) At room temperature, a full O2 cylinder is at 136 atm. Of
pressure or 2000 lb/in2 and contains 625 L of gas.
b) Oxygen behaves as an ideal gas: pV=m/MRT, where
V=volume, m=mass, M=molecular weight, R=universal
gas constant
c) for any isothermal process (T is constant) the product pV
is constant (boyle’s law)
d) for an isobaric process (p is constant) the ratio V/T is constant (Charles’ Law)
Nitrous Oxide:
Because the density of N2O vapor at 51 atm and 20 degrees C is less than _ the density of liquid N2O, the tank is actually less than _ full (or <400L) just before the tank pressure begins to fall
breathing circuit with no reservoir
open (open drop)
circle circuit with APL closed
circle circuit with low FGf's
2 circuits with no rebreathing

high FGF's
Closed Circuits

1) Cost containment
2) Heat & moisture containment
1) Slow changes in amount of anesthetic delivered
2) Significant error possible since agent is closed to system over time.
Mapleson Systems
No valves, no CO2 absorption, variable rebreathing
B: SV, FGF .8-2 x mV
B: CV, FGF 2-2.5 x mV
C: SV, FGF 2 x mV
C: CV, FGF 2-2.5 x mV
D: SV, FGF 1.5-3 x mV,
volume of tubing &
reservoir bag must
exceed patients tidal
E: SV, FGF 2 x mV, “T-piece”
F: SV, FGF 2 x mV, “Jackson-Rees”
NonRebreathing Circuits
Mapleson D circuit is commonly used today
Mapleson D-modified “Bain system”

Mapleson F “Jackson-Rees modification of Ayre’s T-piece”
Coaxial “King system” has a single inspiratory limb inside the expiratory limb
Mapleson F “Jackson-Rees modification of Ayre’s T-piece”

1) No valves to open, minimizes the work of breathing
2) Minimizes dead space.
The net result is a more rapid induction of anesthesia, but there is a greater risk of anesthetic overdose
1) Increased heat loss from the patient
2) Decreased humidity of gases
3) Need to deliver a fresh gas inflow more than twice the patient’s minute ventilation wasting large volumes of anesthetics.
All three disadvantages are a result of the
high flow rates in the nonrebreathing circuit
Receives gas from the machine (APL) and ventilator
Positive pressure relief valve will allow gas to escape from the system to the OR if pressure builds up in system
Wall evacuation system requires the needle valve to be properly adjusted. If excess flow is present then the negative pressure relief valve opens and waste gas enters the OR
Adjusting the needle valve alters the flow of waste gases into the vacuum source. Adjusting the needle valve does not regulate vacuum or suction
Physics: All anesthetic vaporizers are designed to convert liquid anesthetic into vapor in a controlled fashion
Vapor: Gaseous phase of a substance that is liquid at room temperature and atmospheric pressure
Interlock System: Prevents more than one vaporizer from being turned on at a time. Also ensures vaporizers are locked in so leaks are decreased and vapor output is minimal when the vaporizer is off
Vapor Pressure:
Pressure exerted by the gaseous phase of a liquid substance. Molecules strike the container walls exerting pressure against the container
Saturated Vapor Pressure:
Maximum possible pressure at a given temperature. Equilibrium is established where the number of halothane molecules leaving the liquid phase equals the number re-entering the liquid phase from the gas phase.
1) Increased T = Increased VP
2) Increased liq. T = eventually VP = atmospheric pressure
3) Pressure, this occurs at the boiling point of the liquid
4) Reducing the atm. P = reduces the boiling point
5) T dependent change in anesthetic VP is why anesthetic vaporizers need temperature compensation.
6) Temperature compensation allows a constant concentration output as the liquid anesthetic changes temperature during use of a vaporizer. As liquid anesthetic is vaporized, energy is removed from the liquid and the vaporizer, and the liquid anesthetic temperature will decline.
Specific Heat:
Amount of energy (in calories) required to increase 1 gram of substance 1 degree C. Therefore, substances with a low specific heat are easy to heat up, and those with a high specific heat will require more energy to heat.
Thermal conductivity:
Measure of the speed with which heat energy can flow through material. The greater the thermal conductivity, the better the material conducts heat. This allows for better flow of heat from the environment to the vaporizer and then to the liquid anesthetic.
Calculating vaporizer flow output:
Halothane VP=243, want 1% concentration @ 5L/min @760 mmHg (torr). 760 is sea level.
243/760 = .32, thus, 1/3 of the vaporizer output is saturated halothane vapor.
Most modern vaporizers:
Variable bypass, concentration calibrated, flow over, thermocompensation, agent specific, plenum type vaporizers. Exceptions are Siemens and Desflurane vaporizers.
Malfunctioning vapoprizers:
Incorrect filling, pumping/pressurizing, tipping, internal failure.
Desflurane vaporizer:
Boils at 23.5 degrees C., heated electrically to keep it in the vapor state (2 atm) which drives the agent towards the fresh gas flow. In contrast to other vaporizers, no fresh gas flow goes through the desflurane sump. Vaporizer will shut off if power goes out. In TEC 6 vaporizer, Des is heated to 39 degrees C.
Problems & Hazards-vaporizers
Administration of incorrect agent
Overfilling with agent
Simultaneous inhaled agent administration
Electronic Failures
Problems & Hazards
1) Hypoxia:
Incorrect gas supplied from cylinder
Hypoventilation or low flows
Insufficient gas in the system
Kinked/compromised tube
2) Hypercapnia:
Hypoventilation, low flows
Inadvertent administration of carbon dioxide
Rebreathing without CO2 removal
Unidirectional valve problems
3) Breathing circuit: disconnected, occlusion, high flow
4) Bellows: leaks from improper seating or holes in bellows
5 tasks of O2 in the SPDD model
low pressure alarm
ventilator driving gas
oxygen flush
failsafe for n20, air
The ______ is the ultimate destination of gases.
scavenging system
hospital pipeline pressure
50 psi
low pressure componenents [4]

(distal to flowmetere needle valve)
thorpe tubes
check valves (if present)
common gas outleet
intermediate pressure components (exposed to pipeline pressure)[6]
pipeline inlets, check valves, guages
ventilator power inlet
oxygen pressure failure devices
flowmenter valve
oxtgen second stage regulator (if present)
fluch valve
high pressure components
(exposed to cylynder pressure)(4)
hanger yoke
yoke block with check valves
cylinder pressure regulators
cylynder pressure guage
______ are a comm on source of leaks
o-rings at pipeline
working pressure of machine
pipeline pressure
tank pressure
50 psi
45 psi (after regulator)
at the pipeline a __, __ and __ are present
check valve
pressure guage
required components

backup battery life
30 minutes
required components

high priority alarm

must sound if [3]
-may not be silences for more than 2 minutes

1-if user adjustable limits are exceeded
2-if continuing high pressure is sensed
3-for negative pressure
required components

disconnect alarms may be besed on [3]
low pressure
exhaled volume
required components

automatically enabled alarms [4]
-breathing circuit pressure
-oxygen concentration
-exhaled volume
-carbon dioxide monitor
required components

monitors {8}
-exhaled volume
-inspired oxygen (30sec-if <18% FI02)
-oxygen supply failure alarm
-hypoxic guard system
-anesthetic vapor concentration
-pulse oximetry

pressure in breathing system is limited to ______
125cm H20

the cylindeer
at least one oxygen cylinder
pin indexed
pressure guage

the machine must use the pipeline supply as long as the pressure is greaeter than 50 psi

flowmeters [7]
-single for each gas
-flow control next to flow indicator
-fluted knob (different for 02)
-valve stops
-02 flow is on the right
-02 enters manifold downstream of the other gasses
-an auxillary flowmeter is strongly recommended

02 flush [3]
-an 02 flush must be present
-capable of 35-75 lpm
-does not go through any vaporizers

vaporizers [6]
-concentration calibrated
-an interlock must be present
-liquid level indicator
-designed to prevent overfilling
-should used keyed devices
-no discharge of liquid even at max FGF

common gas outlet [4]
-only one CGO
-22mm outer diameter
-15mm inner diameter
-designed to prevent accidental disconnection

pipeline gas supply [5]
-pipeline pressure guage
-inlets for at least 02 and N20
-DISS protected
-in-line filter
-check valve

a ______ data interface must be provided
In the event of a suspected cross-over, what do you do? [3]
-open emergency 02 cylinder supply,
-disconnect pipeline supply
-consider low FGF, manual ventilation
the 02 tank has to be a minimum of ____ psi.
1000 psi
cylinders use the ______ pin index system
hanger yoke 3 functions
-orients cylinders
-provides a gastight seal
-endures unidirectional flow

also has a mandatory filter and check valve.
transfilling is a haxard because...
cylinder filling creates HEAT
What is the rationale for keeping cylinders closed during normal pipeline supply operation?
there is no alarm when switching to the cylinder, there would be no alarm if the pipeline supply fails and the only alarm would be when the emergency supply is empty.
______ the plastic cover on the port when installing.
always use a ______ when removing a cylinder from the hanger yoke.
yoke plug
When installing a cylinder. [7]
-check labels
-crack vavle
-check PISS pins
-check for one washer only
-place in hanger yoke
-listen for leak
-check for proper pressure
amount of gas remaining equation...
capacity (l) divided by service pressure (psi) = remaining contents 9l0 divided by guage pressure (psi)
the use of a mechanical ventilator uses approximately _____ of driving gas each minute.
a minute volume
N20 frost starts at
4 lpm
N20 is flammable?
non-flammable, but supports combustion
Drager Fabius GS
-piston driven ventilator
-thermal anemometry (hot wire) flow sensor
-can do PCV
-variable bypass vaporizers (no tool needed)
-cicuit volume 2.8l of which 1.5l is absorbent volume)
-only loosse granules
-45 minute battery
Drager Narkomed 6000/6400
-piston driven ventilator
-ultrasonic flow ssensor
-can do PCV/SIMV
-variable bypass vaporizers (no tool needed)
-circuit vol (1.5l absorb)
-only loose granules
Datex-Ohmeda Aestiva
-gas driven bellows
-high volume circuit (5.5)
-30 minute battery
Datex-Ohmeda S/5 ADU
-gas driven bellows
-variable bypass vaporizers (no tool needed)
-very low volume circuit (only 750ml absorb)
most fragile part of machine?

turn off before connecting gas and at end of day.
excessive use of the flush valve can result in..
dilution of inhalatinoal agents leading to a decreased depth of anesthesia
failsafe mech's do what
prevent the delivery of a hypoxic gas mixture in the event of 02 supply failure
low pressure alarms
______ ventilators can be used outside of the OR for prolonged periods because..
they use electric motors to comp0ress the bellows, therefore not exhausting the FGF supply
all current machines incorporate hypoxic guard system that limit to final misture to at least ______ % 02
25% +/- 4%
a vapor is compsed of molecules that are liquid at __ and __
room temp and q atm.
as evaporation proceeds, the remaining liquid and it's container cool because..

this is called the...
heat enregy is carried from the liquid with the energetic, mobile evaporating molecules (joule/thompson effect)

the latent heat of evaporization
______ limits the rate of evaporization
vaoprizers need a _____ and _____ to stabilize anesthetic temperature
high thermal conductivity

high thermal capacity
the rate of evaporization depends on [4]
vapor pressure of the liquid
partial pressure of the vapor above the liquid
the splitting ration is the..
gas entering the chamber divided by the FGF.

automatically determined by variable bypass vaporizeers
the flow entering the chamber is called the [2]
chamber flow
carrier gas
full saturation of the carrie gas is by means of ___ and _____
sa the vaporizer cools more/less gas is directed into the chamber?
variable bypass vaporizers are in/out of the circut?
measured flow vaporizers..
can be used with any agent
operator deterimes amount of gas bubbled through the liquid by a formula
called maula temperature compensation
which vaporizer is heated for des?
datex-ohmeda Tec 6

heated dual circuit 39C, 1500mm

uses a vapor-circuit that is mised with FGF circuit
The modern vaporizors output may be influenced by [3]
extremes of FGF
extremes of temp
backpressure from the vent/circuit
what limits the 'pumping effect'?
a unidirection valve at the chamber inlet or distal to the vaporizer
What prevents the operator from delivering more that one agent at a time?
interlock system
variable-bypass vaporizers must be on/off while filling?
preop check for VB vaporizers? [3]
are they full?
are they on off?
is the interlock funtioning?
preop check for Tec-6(des)?
check alarm-low battery
turn on at 1%, pull plug, alarm in 15 sec (no output alarm)
trun off reconnect power, mute for 4 sec to test alarms and display
The purpose of the anesthesia breathing circuit is...
delivery of 02 and elimination of C02
advantages of a rebreathing circuit are...[3]
cost reductions
warmth and humidity
decreased exposure to gases
Va=VE - ______
dead space
the most common circuit is the ___

the Bian modification is...

how to test?
mapleson D

the FGF is inside the inspiratory corrrugated tubing.

must use the Pethick test
The minimm weight of a child in whom a pediatric circuit would be suitable is __ to __
The FGF required to prevent rebreathing is_____
2 to 3 times the VE
breating circuit system most commonly used is-----
circle system
gas enters the circle system from the _____ and exits at the ____

only 2 reasons for an increase in inspired C02
exhausted absorbent granules
faulty unidirectional valves
The time constant equals ____ divided by ____ and measures how quickly a breathing system reaches equilibruim with changes in inlflow.
The correct response to increased C02 resultinmg from exhausted absorbant is...
increase GFG (NOT Ve)
The absorption of 1 mol of C02 produces ____ Kcal of heat energy
at a critical ph of _____ ethyl viloet changes to bluish purple
main constituent of sada lime?

ideal water %?

calcium hydroxide


4-8 mesh
soda lime degredation...

most-Sevo (compound A)

Sevo low FGF #'s?
total FGF's of less tha 1 LPM for more than 2 MAC hours
Carbon monoxide produciton,


gretest with baralyme
____ is the new absorbent
absorbent/canister resistance?
less than 1.5 cm at a flow of 100LPM
after a pressure check, always release the pressure throught the ____
APL valve
Do/don't replace canisters in the middle of a case?

each 100gm of granules can absorb as much as ______ of C02
15 liters

we produce about 12-18 liters per hour
fires may occur if sevo is used with..
a dessicated absorbent
There is ________ PEEP in the breathing circuit when standing bellows mechanical ventilation is used
______ bellow are the safest.
typical CMV settings
10ml/kg VT
rr 6-12
0 peep to start
PCV indications
low complicance
no inherent PEEP with _____ ventilators
piston driven
______ helps to ensure that the set and delivered tidal volumes are equal.
FGF decoupling
____ is the most common preventable equipment related cause of mishaps
failure to ventilate caused by disconnection
the m ost important monitor for disconnection is _______ and ______
continuous aucultation

direct visualizatin of chest wall movement
how much gas is scavenged each minute?
an amount equal to FGF
The most important componetn of the scaveging system is the...
interface, because it proects the patient adn breathing circuit from excessive buildup of positive pressure and from exposure to suction.
______ is mandatory for all closed scavenging interfaces (older machines)

with an open system there are no ______ to impede flow into or out of the reservoir

_____ is critical to scavenging system fucntion
relief of pressure

no valves in open

an appropriate suction device
The open scavenging system interface should/should not hiss if functining properly
should HISS
leaks in the low pressure system could lead to _____ and ______
hypoxic breathing mixtures

awareness under anesthesia
what do you do?

decreased FI02?
call for help
open the cylinder and disconnect the pipeline
if that doesn't increase the FI02, ambubag with room air
what do you do?

Pethick test for Bain circuit.
occlude elbow
close APL
fill circuit with flush valve
release occlusion at elbow and flush. a venturi effect flattens the reservoir bag if the inner tube is patent
what do you do?

sustained high breathing circuit pressure?
1-try manual ventilatin in BAG mode (that works, you have a faultyventilator releif valve-new vent)
2-scavenger could be obstructed or its relief valves failed
3-disconnect the scavenger gas collectin tubing from the back of the APL
4-if still nogo, then ventilate by ambu bag
with AIDS..
avoid using mechanincal ventilators
use bacterial and virela filters on each limb
use a dispoisable soda lime assembly
change soda lime after each
Wash in time constants
1 time constant=capacity/flow

density equation
density = weight x volume
ideal gas law
PV = nRT

n=number of gas molecules
r=contant for all gases
t=absolute tem (in kelvin)

kelvin = C+273
Boyle's law
expresses the compressability of gases


constant temp
Charles's Law
if pressure is held constant, the volume of expansion is proportional to the absolute temperature


constant pressure
Gay-Lussac's law
When volume is held constant, gas pressure varies directly with absolute temperature


volume is constant