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91 Cards in this Set
- Front
- Back
How do gases come to the anesthesia machine?
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Pipeline- wall outlets, connecting valves and hoses, filers and check valves, pressure gauges
Cylinders- hanger yolks, filters and check valves, pressure gauge, pressure regulators |
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how does the anesthesia gas machine prepare gases before their delivery to the patient? & what are some aspects of processing?
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Site:within the machine, proximal to common gas outlet
Failsafe- o2 pressure-failure devices, flowmeters, o2 flush, low o2 alarms, venilator driving gas, proportioning systems (hypoxic gaurd), vaporizers, common gas outlet |
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how is the interaction of gases with the patient controlled and monitored?
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(site breathing circit)
gas delivery hose connecting common gas outlet and breathign circit -carbon dioxide absorber ventilators integral monitors (o2 analysis, disconnect, spirometer, capno, airway pressure, vent alarms) -Peep -humidification |
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how are gases disposed of?
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scavenger system
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what is the primary gas source pressure and what is a full cylinder pressure?
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pipeline pressure is 50psi
O2 cylinder pressure full is 2000psi |
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What are required monitors on an anesthesia machine?
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Exhaled volume
Inspired oxygen, with a high priority alarm within 30 seconds of oxygen falling below 18% (or a user-adjustable limit). Oxygen supply failure alarm A hypoxic guard system must protect against less than 21% inspired oxygen if nitrous oxide is in use. Anesthetic vapor concentration must be monitored. Pulse oximetry, blood pressure monitoring, and EKG are required |
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what is o2 flush pressure?
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25-75 L/min
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How are pipeline linlets connected?
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Pileline inlets are connected with DISS (diameter index saftey system) non-interchangeable connections.
The check valve (located downstream form the pipeline inlet) prevents reverse flow of gases (from machine to pipeline) |
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What are the colors for o2, no2, and air?
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o2 green
o2 blue air yellow |
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Cylinder saftey system?
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PISS Pin index saftey system prevents misconnection of a sylinder to the wrong yolk.
Use only one washer!! |
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What does the hanger yolk do?
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Hanger yolk orientes cylinders, provides unidirectional flow and ensures gas-tight seal
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cylinder pressure regulator converts ___ cylinder pressure to a constant prssure of ___ downstream of the regulator?
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cylinder pressure regulator converts HIGH cylinder pressure to a constant prssure of 45 downstream of the regulator?
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Devices and techniques which do NOT rely on wall outlet electrical power include?
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spontaneous or manually assisted ventilation
mechanical flowmeters scavenging laryngoscope, flashlights intravenous bolus or infusion battery operated peripheral nerve stimulators or intravenous infusion pumps monitoring using the anesthetist's five senses |
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In the event of a o2 crossover ( o2/no2) or low o2 pipeline pressure what should the CRNA do ?
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turnb on backup o2 cylinder and disconnect o2 pipeline supply hose from the wall (because the gas will flow from whichever has the highest pressure, pipeline 50 psi, cylinder 45psi)
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Does the fail- safe system prevent a hypoxic mixture from being delivered?
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NO! only the hypoxic gard only connects o2 and no2 flowmeters.
The failsafe ensures the o2 concentration is delivered (pressure) |
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What should you do if you lose o2 pipeline pressure?
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Same as a crossover! Open the o2 cylinder completely and disconnect the pipeline because it delivers a higher pressure than the cylinder! o2 analyzer should warn of a crossover or the pulse ox will after all o2 is washed out of the FRC! and Ventilate by hand because it uses less o2 than the vent!
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Proportioning Systems are the board exam terminology for the hypoxic guard system. What do they do?
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These systems link nitrous oxide and oxygen flows (mechanically, pneumatically, or electronically) to prevent final inspired oxygen concentration less than 0.25.
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How to eliminate Co2 during anesthesia?
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Co2 is eliminated by washout with FGF or soda lime absorption
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What is vent deadspace for
VD/VT= ____ normally, ___ if intubated ___mask case. |
Dead space is increased (by all respiratory apparatus). VD/VT= 0.33 normally, 0.46 if intubated and 0.65 if mask case.
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What is the soda lime activators?
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NaOh or KOH
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Capnography has been shown to be effective in the early detection of? (4)
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adverse respiratory events
malpositioning of ET tube Circulatory failure defective breathing circuits |
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True or False? Capnography is the best method to confirm correct placement of the ETT?
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TRUE
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PHYSICS: This technique is the most popular for monitoring and analysing gases. It absorbs specific wavelengths.
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Infra Red Spectrography
(Oxygen does not absorb IR light and is not measured using this technique) |
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What is the correlation between PaCo2 and ETCO2?
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ETCO2 is 5-10 torr lower than PaCO2
(because ETCO2 is diluted with alveolar deadspace gas from under perfused alveoli) |
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Name some problems with pipeline supply?
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pressure loss, excessive pressure, cross-connection of delivery pipelines, contamination, leaks
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True or False? Always trust the oxygen analyser until you can prove it wrong?
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TRUE
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what is the function of the pipeline inlet check valve?
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unidirectional flow
prevents retrograde flow |
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what is the most fragile part of the cylinder?
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cylinder valve! protect it during transport
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What are the 3 functions of the hanger yolk?
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orientes cylinders, provides a gas-tight seal, ensures unidirectional flow
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What will happen if the oxygen cylinder is left open after checking it and pipeline pressure fails?
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Nothing, the operator will not be alerted to the failure because gas will simply begin to flow from the cylinder due to it becoming the higher pressure.
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Which reglitory agency issues regulations for the manufacture, handling, transport, storage and disposal of cylinders?
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Department of transportation
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name 4 circumstances can permit a hypoxic mixture even when the hypoxic gaurd system is employed?
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1. wrong supply gas in oxygen pipeline or cylinder
2. defective pneumatics or mechanics (hypoxic gaurd system is broken) 3. leaks downsteram of flowmeter control valves 4. inert gas administration (third gas such as helium administration) O2 analyzer is of great importance!!!! |
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Name the only system that ensures that oxygen is present
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ONLY ONE SYSTEM that ensures that oxygen is present in the oxygen pipeline or cylinder: the inspired oxygen analyzer
supply failure alarms warn of trouble with o2 supply & hypoxic guard and fail-safe systems lessen the chance of hypoxemia but are based on pressure within the system. They do not sample the lines to determine that o2 is present. |
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Does a face mask or ett have greater deadspace?
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face mask
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Where does deadspace end?
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Deadspace ends where the inspiratory and expiratorygas streams diverge. in a circle system this is the y piece
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Can you have a semi-open classicication with a circle system?
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yes, at high fresh gas flow (more than minute ventilation) or with the use of a nonrebreathing circuit
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for a closed breathing circuit the flow should be (high/low) and the APL valve should be ____?
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for a closed breathing circuit the flow should be HIGH and the APL valve should be CLOSED?
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4 common reaturs of nonrebreathing systems
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NO UNIDIRECTIONAL VALVES
NO SODALIME/ CO2 ABSORPTION REBRETHING IS HIGHLY DEPENDENT ON FGF LOW RESISTENCE |
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NAME 3 NON-REBREATHING (semi-open) CIRCUITS
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BAIN
MAPLESON CIRCLE WITH HIGH FGF (GREATER THAN MINUTE VENTILATION) |
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2 causes for increase in inspired co2?
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exhaused co2 absorber
unidirectional valves are faulty |
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if inspired co2 on the capnogrophy is 1-3 mmhg what can be done?
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increase FGF to 5-8L (this converts the closed system to a semi-open and minimized rebreathing of exhaled gases.
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How do you check the unidirectional valves?
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place a reservoir bag on the y piece and mechanically ventilate watching the valves.
or occlude one side at a time and breath into the unidirectional tubing. should only be able to expire not inspire on the expiratory limb and viseversa |
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carbon monoxide is most common with which agent____ and with a __dry/moist__ absorbant?
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carbon monoxide is most common with des and with dry absorbent.
it is recommended that o2 be turned off at the end of each case to keep grandules moist. |
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Carbon dioxide absorbers recommendations?
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1.turn off all gases when not in use
2. change absorbent regularly 3. change both canesters not just one 4. change absorber if hydration state unknown of if gas left on overnight/weekend 5. low flows preserve humidity, dry absorbent exhausts quickly |
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2 examples of open breathing systems?
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nasal canula
open drop ether |
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this type of breathing system has a minumum FGF of 5L/min
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semi-open. 5L/Min required to prevent rebreathing
the FGF exceeds minute ventilation 2-3 times |
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this is a version of the mapleson D with 200-300cc/kg/min for spontenaous and 70cc/kg/min for controlled
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Bain
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describe the bain system including the tube, where FGF enters, and FGF required for spontenous and controlled ventilation
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bain system is a coaxial tube (tube within a tube)
FGF enters though a narrow inner tube FGF to prevent rebreathing 200-300ml/kg/min with sponteneous breathing and 70mg/kg/min with controlled vent. |
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name advantages of bain system
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warming and humidification of gases
ease of scavenging APL valve disposable |
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does the semiclosed circle system allow for rebreathing of exhaled gases?
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partial
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does the semiclosed circle system have sodalime?
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yes
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true or false, semiclosed circle system has a higher FGF than minute ventilation?
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false, FGF is less than minute ventilation
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name the 7 components of the semi-closed circle system
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FGF
inspiratory and expiratory unidirectional valves insp aind exp corrugated tubes y piece apl reservoir bag co2 absorbent |
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name 3 advantages to a semi-closed circle system
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consistancy of inspired concentration
concserves resp moisture minimal pollution (scavenging) |
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What is the APL valve
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limits the amount of pressure build up that can occure during manual ventilation
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if you have no air in you resevior bag is you pop off valve open or closed
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open
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what is the reaction with a co2 absorber?
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a BASE neutralizing an ACID
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name 3 endproducts of CO2 absorber reaction
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heat, water, carbonate
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what is the mesh size of the granules for co2 absorber
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4-8 mesh. higher the number smaller the granule
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carbon monoxide production increases with (4)
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des (and other agents)
low fresh gas flows high concentrations of agents dry absorbent |
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what is the nitrous oxide cylinder pressure when full
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745psi
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what does the failsafe gaurd against?
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decrease oxygen pressure
if pressure is lost the failsafe shuts off the flow of all other gases. can NOT DETECT A CROSSOVER |
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what does the hypoxic gaurd?
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works on oxygen pressure. it controls the ratio of oxygen and nitrous oxide so that there is a minimum of 25% oxygen. it does not analyze the gas.
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what 2 devices willl inform you of a crossover of o2 and n2o?
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FIRST- oxygen analyzer
second- pulse oximeter |
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how do you calculate how long your cylinder will last?
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contents L/gauge pressure= capacity L/ service pressure
EX: xL/1000psi(whats left in container)= 660L/ 2000psi answer is in L then divide by however many L/min. |
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2 things that can cause high positive pressure to the patient that are related to the anesthesia machine?
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obstruction of the scavenger
failure of the ventilator relief valve |
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what is the most common site for disconnecton? and what is the most important monitor for disconnection?
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common site is y piece
monitors for disconnect: apnea, circuit pressure, co2, acustic sound of ventilator or percordial steth. |
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What is the preferred bellow design and why?
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descending bellows do not indicate a disconnection and it collects exhaled humidity
ascending is best!! |
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every vent is different, what is the best way to initiate machanical ven
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switch to bag/vent
make sure the vent starts to cycle (check for chest expansion with the first breathing cycles) review mode, volume or pressure, and rate settings |
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during an emergency what is the minimum that must be checked even when time is at a premium?
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1. high pressure test of the breathing circuit (ensure no leaks are present distal to the common gas outlet)
2. when placing the mask on the patients face to rpe-oxygenate them always observe or palpabe the breathing bag for fluctuation (flow) 3. check suction |
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what is the best way to preoxygenate?
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4-6L/min FGF
apl fully open tight mask 3-5 min of TB or 4-8 vital capacity |
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what is the threshold for smelling volatile agents and what is the NIOSH standard concentration amount?
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smelling agents 5-300ppm and standard is not more than 2ppm
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if you can smell an agent what should you do? what are the causes?
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poor mask fit
unscavenging technique such as insufflation agent on before mask is on patient spilled agent uncuffed tracheal tube machine leak increase scavenger |
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if your fgf is 4L/min how much is scavenged per minute
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must be the same amount or else barotrauma
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this system consists of a NEEP and PEEP relief valve
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scavenging system
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This alarm system detects disconnects, major air leaks, leaking tracheal cuff and failure to cycle
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LOW PRESSURE ALARM
This alarm system detects disconnects, major air leaks, leaking tracheal cuff and failure to cycle |
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This alarm system detects airway obstruction, laryngospasm, decreased lung compliance (bronchospasm), kinked or occluded ETT, patients coughing against ETT, occlusion of expiratory limb
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HIGH PRESSURE ALARM
This alarm system detects airway obstruction, laryngospasm, decreased lung compliance (bronchospasm), kinked or occluded ETT, patients coughing against ETT, occlusion of expiratory limb |
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This alarm system detects NG tube in the trachea, blocked inspiratory limb, malfunctioning scavenging system, inhalation against an empty reservoir bag
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SUB-AMNIENT PRESSURE
This alarm system detects NG tube in the trachea, blocked inspiratory limb, malfunctioning scavenging system, inhalation against an empty reservoir bag |
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The apnea pressure alarm limit should be adjusted as close as possible to the patients ____ without exceeding it?
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PIP
because... if threshold is too low it will not detect partial breathing, leaks, or disconnect. ALARM WILL NOT SOUND. |
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When preoxygenating your patient what should your FGF be? APL valve?
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8-10 L and APL should be OPEN
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3 Pressure relief valves for cylinders? (can have one or more of the following)
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fusible plug (thermally operated)
frangible disc (burst with high pressure) safety relief valve (opens under high perssure) |
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what is the fail-safe valve and where is it located?
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controlled by oxygen poressure, it senses a drop in o2 pressure (below 12-30) and (shuts off or proportionaly decreases supply of N2O.
Located in-line between the N2O supply and the flowmeter (can not sense a crossover) |
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what is the fail-safe valve and where is it located?
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controlled by oxygen poressure, it senses a drop in o2 pressure (below 12-30) and (shuts off or proportionaly decreases supply of N2O.
Located in-line between the N2O supply and the flowmeter (can not sense a crossover) |
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Give examples of ways the the fail-safe system helps prevent hypoxia?
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disconnects, low 02 pressure in pipeline, depletion of o2 cylinders
EX: disconnect the o2 and the No2 shold decrease to zero |
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Give examples of ways the the fail-safe system helps prevent hypoxia?
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disconnects, low 02 pressure in pipeline, depletion of o2 cylinders
EX: disconnect the o2 and the No2 shold decrease to zero |
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Where is the oxygen analyzer positioned?
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inspiratory limb
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Where is the oxygen analyzer positioned?
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inspiratory limb
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what is part of the low pressure system?
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vaporizers, common gas outlet, flowmeters
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what is part of the low pressure system?
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vaporizers, common gas outlet, flowmeters
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Where is the hypoxic gard system located?
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flowmeters, minimum oxygen ratio device, actively increases o2 when n2o is increased
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Where is the hypoxic gard system located?
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flowmeters, minimum oxygen ratio device, actively increases o2 when n2o is increased
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