Gas Machine Part I Flashcards
What are the four common anesthesia machine manufacturers? (4)
- Drager
- GE
- Penlon
- Mindray
What are some examples of the drager anesthesia machine? (7)
- Perseus A500
- Apollo
- Fabius GS Premium
- Fabius Tiro M
- Fabius Tiro
- Fabius MRI
- Narkomed
What are some examples of the GE anesthesia machine? (3)
- Aisys CS2
- Aestiva
- Avance
What are some examples of the penlon anesthesia machine? (3)
- Prima 465
- Prima 460
- Prima 450
What are some examples of the mindray anesthesia machine? (3)
- A7 Advantage
- A5 Advantage
- A4 Advantage
What are the four systematic components of the anesthesia gas machine?
- Supply
- Processing
- Delivery
- Disposal
Review the gas machine systematic approach diagram.
What are the different pressure systems of the anesthesia gas machine (3)?
- High-Pressure System
- Intermediate Pressure System
- Low-Pressure System
What is the definition of high pressure system?
Exposed to cylinder pressure
What are components of the high pressure system? (4)
- Hanger yoke
- Yoke block with check valves
- Cylinder pressure gauge
- Cylinder pressure regulators
What are components of the intermediate pressure system? (6)
- Pipeline inlets, check valves, and pressure gauges
- Ventilator power inlet
- Oxygen pressure-failure devices
- Flowmeter valve
- Oxygen second-stage regulator
- Flush valve
What is the defition of intermediate pressure system?
Exposed to pipeline pressure
What is the typical pipeline pressure?
50 PSI
What is the definition of low pressure system?
Distal to flowmeter needle valve
What are the components of the low pressure system? (4)
- Flowmeter tubes
- Vaporizers
- Check valves
- Common gas outlet
Review Box 16.22 – Summary of preanesthesia checkout recommendations
What is a compressed gas?
is any material or mixture having in the container either an absolute pressure exceeding 40psi at 70◦F or an absolute pressure exceeding 104psi at 130◦F or both
How is compressed gas supplied?
Cylinder & Pipeline
What compressed gas source is found at hospitals?
Pipeline- Main hospital bank
How is oxygen manufactured?
Fractional distillation of liquefied air
What gas supply is the only essential one needed?
Oxygen
What happens to oxygen?
Liquid converted to gas
What is the PSI of pipeline oxygen?
50psi
How is oxygen stored?
Cylinder or tank
What are components of liquid oxygen?
Large flask outside of hospital
How much space does liquid oxygen occupy?
Liquid occupies 1/860 of the space the gas would occupy
28.3 liters of liquid oxygen produces ________ of gas
24,338 liters
What is the temperature oxygen is stored at?
-160◦C
How is nitrous oxide commerically manufactured?
by the thermal decompensation of ammonium nitrate
What are components of nitrous oxide formation?
- Nitrous oxide, water and other toxic impurities are present in the initial reaction
- Further purification is achieved by removing water condensation
What is the minimum that nitrous oxide must contained?
Nitrous oxide cylinders must contain a minimum of 99% nitrous oxide by volume
What is nitrous oxide classified as?
a non-flammable gas but supports combustion
How is nitorus oxide delivered to hospitals?
in H cylinders
What are the two types of compressed gas?
Non-Liquified vs. Liquified
What is non liquified gas?
A gas that does not liquefy at ordinary temperature and ambient pressure
What are examples of non liquified gas? (4)
- Oxygen
- Nitrogen
- Air
- Helium
What is true about the relationship between pressure and non liquified gases?
- Pressure in the cylinder declines steadily as the contents are withdrawn
- Pressure can be used to measure the cylinder contents
What is liquified gas?
A gas that becomes liquid in containers at ordinary temperatures and pressures ranging from 25 to 1500psi
What are examples of liquified gas?
- Nitrous oxide
- Carbon dioxide
What is the relationship between liquified gas and pressure?
- Pressure in the cylinder represents an equilibrium between the liquid and the gas above the liquid
- Pressure remains nearly constant if the temperature remains constant until all of the liquid has evaporated
What is the measurable volume and pressure found in a full tank of non-liquified gas?
- Volume: 660 L
- Pressure: 1900 psig
What is the measurable volume and pressure found in a 50% full non-liquified gas?
- Volume: 330L
- Pressure: 950 psig
What is the measurable volume and pressure found in a 25% full non-liquified gas?
- Volume: 165 L
- Pressure: 475 psig
What is the measurable volume and pressure found in a empty tank non-liquified gas?
- Volume: 0L
- Pressure: 0psig
2000psi = _____ of oxygen
660L
1000psi = _____ of oxygen
330L
You are assigned to transport a patient in the MRI suite. Your oxygen tank regulator shows 1000psi. Oxygen liter flow is 6 liters via simple face mask.
- How many minutes of oxygen remain for this patient?
1000psi = ~330L/6L flow = 55min of oxygen remain in tank
You arrive at the general hospital and the physician you are working with informs you that the main oxygen system is down for the day due to pipeline work. Your oxygen tank shows that you have 500psi in tank #1 and 1000psi in tank #2 on your anesthesia gas machine.
As you begin your six hour re-do fractured hip case, you can expect to change oxygen tank #1 at how many minutes into the case?
Flow rates for the case: 2L/min oxygen and you are not using a ventilator
500psi = ~165L/2L flow = 82.5 minutes remaining
As you enter the hospital you notice a visitor has fainted in the lobby. The EMS arrive for transport. Prior to transporting, you notice that there is 2000 psi left in the oxygen transport tank. The patient is on 4L/min oxygen via nasal cannula
- How much time remains in the oxygen tank?
2000psi = 660L/4L flow = 165 minutes
What liquified compressed gas is represented here and why?
Nitrous Oxide
- Liquid at room temperature and can not estimate the volume left in the tank
What is true about the nitrous oxide gauge?
Nitrous oxide cylinder pressure gauge remains at 745psi until the liquid is gone
What is true regarding gas removed from the nitrous oxide tank? When should be done if the pressure reading is less than 745 psi?
- Three-quarters of the gas is removed and pressure will decline rapidly with further use
- Change cylinder if pressure reading is less than 745psi
What can occur ith rapid removal of nitrous oxide? What is the cause of this?
- Rapid removal of nitrous oxide from cylinder (greater than 4L/min) may cause formation of frost on cylinder wall or freezing of valve
- Caused by loss of the latent heat of vaporization
Whast is the property of nitrous oxide?
Non-flammable but supports combustion
How is transportation of regulate compressed gas?
- Department of Transportation (DOT): Regulations r/t: manufacture, handling, storage and disposal
How regulated and sets the cylinder standards of compressed gas?
Compressed Gas Association & National Fire Protection Association
How regulates the purity of compressed gas?
- United States Pharmacopeia (USP)
- FDA
What are the advantages to the pipeline system? (3)
- Cheaper
- Less dangerous than cylinders
- Convenient
What is true about pipeline pressure?
- Gas is delivered at a reduced pressure of 50psi
- Pipeline pressure may vary depending on the demands of the facility
What connects the Pipeline system?
Couplers used to connect AGM and supply hoses
Why is couplers used to connect the pipeline system?
Springs and rubber gaskets (O-rings) can provide a less than secure connection
What type of tubing is used in the pipline system?
Copper tubing is clean and rust free
Who regulates the pipline system?
- National Fire Protection Agency requires seamless or standard weight copper
- Copper tubing is cleaned and dried thoroughly prior to installation
What happens to the pipeline system after it installed?
blown clean of oil, nitrogen and air after installation
What is the safety system of the pipeline?
Diameter Index Safety System
What is the Pipeline: Diameter Index Safety System designed to prevent?
Designed to prevent misconnection of medical gases via pipeline system
How does the Pipeline: Diameter Index Safety System work?
The end of the hose for each type of medical gas is assigned a unique diameter and thread that is used to connect the pipeline gas to the AGM
Where does the pipeline connect on the AGM?
Supply hoses connect pipeline inlets on back of AGM to wall/ceiling outlets
What is at the pipline inlet? (3)
At pipeline inlet there is a filter, check valve and pressure gauge
Pipline Diameter Index Safety System: What is the filter?
Prevent damage to AGM from particulate matter
Pipline Diameter Index Safety System: What is the Check Valve?
- Ensures unidirectional forward flow
- Prevents leakage when AGM running on cylinder supply and hoses disconnected
What are potential problems of the pipeline system? (6)
- Leaks
- Contamination
- Inadequate pressure
- Excessive pressure
- Accidental crossover
- Theft of N2O for recreational use
What contaimination problems can occur with the pipeline system?
- Particles, bacteria, viral, etc.
- Moisture: Filter placed to prevent damage to the AGM from particulate matter in pipeline gas supply
What inadequate pressure problems can occur with the pipeline system?
- Oxygen low pressure alarm will sound if pressure loss profound
- Fail safe valves stop flow of other gases (e.g. nitrous oxide)
What is accidental crossover?
- Construction
- Renovation
- Likely to see declining inspired oxygen concentrations despite a steady flow of oxygen
- When in doubt, trust oxygen alarm
What are the steps if their is accidental hospital pipeline crossover?
- Trust your O2 analyzer
- Turn on backup oxygen cylinder
- Disconnect oxygen pipeline supply hose from the wall
- Use low flow oxygen with volatile agent
- Ventilate manually thru circle system
Why is it important to disconnect oxygen pipeline supply hose from the wall in the event of pipeline crossover?
- If pipeline not disconnected pipeline gas will flow preferentially over cylinder flow
- Cylinder regulator 45psi vs pipeline pressure of 50psi
- Ensure FiO2 rises (if not – ambu)
What is the PSI of the cylinder regulator?
45 psi
What are the components of “Ventilate manually thru circle system” in pipeline crossover? What is an exception to this?
- An entire E cylinder may be exhausted in less than 1 hour
- Ventilator drive gas may utilize 7L/min or more
- Exception – Piston driven ventilators
How regulates the piping system?
National Fire Protection Agency, Compressed Gas Association and International Standards Organization
How actually approves the pipeline system?
Do not approve the actual pipeline system – that is left to the hospital and gas supplier
TJC requires pipeline compliance with _________
National Fire Protection Agency
What is the component of local law and pipeline regulation?
Frequently local laws regulating hospital pipeline systems are stricter than those organizations identified above
What is the pipeline manual shut off switch?
Isolates a section of the pipeline for maintenance repair, testing or problems distal to the valve
What are ther most common used cylinder sizes?
E and H cyclinders
What are the cyclinder components of oxygen?
(Formula, US color, international color, service pressure, capacity and pin position)
What are the cyclinder components of nitrous oxide?
(Formula, US color, international color, service pressure, capacity and pin position)
What are the cyclinder components of Air?
(Formula, US color, international color, service pressure, capacity and pin position)
What are the cyclinder components of carbon dioxide?
(Formula, US color, international color, service pressure, capacity and pin position)
What are the cyclinder components of nitrogen?
(Formula, US color, international color, service pressure, capacity and pin position)
What are the cyclinder components of helium?
(Formula, US color, international color, service pressure, capacity and pin position)
What is the safety device on each cylinder?
Pin Index Safety System (PISS)
Each cylinder valve has a unique hole mate with pins in the yoke (point where the cylinders attach to the AGM)
What is the goal of Cylinders: Pin Index Safety System (PISS)?
Prevent misconnections
How can Cylinders: Pin Index Safety System be overridden?
PISS system can be overridden if pins are missing/damaged or if more than one washer is used
Label the component of the cyclinder.
What is the most fragile part of the cylinder?
Cylinder valve most fragile part of the cylinder
What are the components of the cylinder valve?
Consists of body, port (point of gas exit), conical depression, holes for pins on the yoke fit and safety relief devices
Id the safety relief valve
What is a complication of the cylinder?
Cylinder rupture
What are the components of cyclinder?
Cylinders constructed of ¼ inch steel
Wht cylinders are used for MRI?
Only nonferrous (aluminum) cylinders for MRI
What is included in the cyclinder devices in the case of the contents increasing in temperature or pressure to allow for controlled release of gases?
Pressure Relief Devices
Define Pressure Relief Devices.
Manufacturers use one or more of the following as a safety relief devices in the case of the contents increasing in temperature or pressure to allow for controlled release of gases
What are examples of Cylinder: Pressure Relief Devices?
- Frangible disk
- Relief valve
- Fusible plug
Pressure Relief Devices: What is the components of frangible disk?
- Predetermined pressure is reached then the disk ruptures and the contents are dispersed
- All or none phenomenon
Pressure Relief Devices: What are the components of relief valve?
- Opens at extreme pressures
- Spring loaded device designed to reclose and prevent gas escape once the condition returns to normal
- Not an all or none phenomenon
Pressure relief valve: What is the flusible plug?
- Wood’s metal
- Bismuth, tin, cadmium, and lead
- Low melting point
- Temperature softens plug with resultant loss of cylinder contents (157-175◦F)
- Plugs metal
- All or none phenomenon
What pressure relief devices are an all or none phenomenon?
Fusibile plug or Frangible disk
What pressure relief devices are not an all or none phenomenon?
Relief valve
Who requires permenant marking on the cylinder?
DOT
What des the designation of DOT3AA2265 denotes?
- denotes the specifications of the cylinder
- DOT=Dept of Transport;
- 3AA specifies type of gas cylinder and material from which it is fabricated;
- 2265 is the service pressure of the cylinder in psig (pounds per square inch gauge)
What does the number 12345 on the cyclinder denote?
Serial number of the cylinder
What does GAS INC on the cyclinder denote?
GAS INC. is the identifying symbol of the purchaser, user or manufacturer of the cylinder, the owner
What does 4-70 on the cyclinder denote?
- 4-70 is the date of the manufacture of the compressed gas cylinder and its original date of testing
- The official mark of the inspect is designated by the boxed XX
- The + sign indicates that the cylinder qualifies for filling to 110% of its normal capacity
What does circled YY on the cyclinder denote?
the identification symbol of the manufacturer
What does the symbols 4ABC75+ on the cyclinder denote?
- The symbols 4ABC75+ are retest markings
- 4-75 represent date of first hydrostatic retest of the cylinder
- means that the cylinder qualifies for 110% filling
- Star indicates cylinder qualifies for a 10 year retest interval
What is the location of the cyclinder label?
Each cylinder must bear a label two-thirds the distance from the bottom of the cylinder
What can the label not cover?
It must not cover markings
What are some singal words included on the cylinder?
- Flammable
- Non-flammable
What are three primary purposes of the hanger yoke?
- Orients cylinders
- Gas-tight seal
- Ensures unidirectional flow into the machine
- Also contains a filter
Why is unidrectional flow by the hanger yoke imporant?
- Decreases risk of transfilling
- Decreases leakage into the atmosphere
- Allows for cylinders to be replaced during use
Hanger Yoke example on anesthesia gas machine.
What is the cylinder regulator?
Two diaphragms connected by a rod move together
What are the components of a cylinder regulator?
- Smaller diaphragm opens or closes high pressure inlet (from cylinder)
- Gas entering regulator presses on larger diaphragm, whose movement closes the inlet
- Gas enters at a rate controlled by feedback loop
- Outlet pressure adjustable with screw and spring
What happens to the high cylinder pressure by the cylinder regulator?
- High (variable) cylinder pressure converted to constant downstream pressure, 45 psi
- Set less than pipeline to prevent silent depletion of cylinder contents
What happens if the cylinder is lfet open and pipeline pressureis less <45 psi?
- gas will flow from cylinder
- No alarm; may not know this is occurring
What is the only alarm that will occur if a cylinder is left open and pipeline pressure <45psi?
- Alarm will only then occur when the oxygen supply is low (low oxygen supply failure alarm)
- Alerts to end of emergency supply rather than beginning
What needs to be done to cylinders after checking them?
ALWAYS close your cylinders after checking them during your AGM check at the start of your clinical day!
What is the bourdon pressure gauge?
A hollow metal tube is bent into a curve, sealed and linked to a clock-like mechanism. The other end is connected to a gas source and soldered into a socket.
What happens to the bourdon pressure gauge?
The flexible tube is connected the high pressure circuit and straightens when pressure is applied
What moves the pointer of the Pressure Gauge: Bourdon?
The attachment mechanism moves the pointer
The AGM high-pressure system consists of components of the AGM exposed to ____________
cylinder pressure
What are components of the AGM high pressure system?
- Hanger yoke
- Yoke block w/ check valves
- Cylinder pressure gauge
- Cylinder pressure regulators
The AGM intermediate-pressure system consists of the components of the AGM exposed to ________
pipeline pressure (approx. 50 psi)
What are the components of the AGM intermediate pressure system?
- Pipeline inlets, check valves, & pressure gauges
- Ventilator power inlet
- Oxygen pressure-failure devices
- Flowmeter valve
- Oxygen second-stage regulator (if present)
- Oxygen flush valve
What requires electric power? (7)
- Ventilators
- Monitors
- Lights
- Digital flowmeter displays
- CPB
- Forced air warmers
- Tec 6 vaporizer and vaporizers with electronic controls (e.g. Aladin cassettes)
What do not require electric power?
- Mechanical flowmeters
- Scavenger
- Variable bypass vaporizers
Electrical power supply functionality varies by _______!
AGM
What do contemporary AGMs have?
- have battery backup that supports a minimum of 30 minutes of limited operation
- May not include patient monitors and/or mechanical ventilation
Definition of ___________ varies from machine to machine
“limited operation”
Where are the electrical outlets located on the AGM?
- located on back
- Protected by circuit breakers and fuses
What are the electrical outlets on the AGM typically used?
- Typically used for monitors
What should the electrical outlets on the AGM not be used for? What can happen?
- Do not use for devices that convert electricity into heat (e.g. warming blankets, fluid warmers, etc.)
- Blow a circuit or and entire machine and anything plugged into it goes down until breaker is reset
What are the five oxygen tasks?
- Proceeds to fresh gas flowmeter
- Powers oxygen flush
- Activates fail safe mechanisms
- Activates oxygen low pressure alarms
- Drives bellows
