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68 Cards in this Set
- Front
- Back
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ASTM
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-American Society for Testing and Materials
-specifies what is needed for anesthesia machines |
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REQUIRED COMPONENTS OF ANESTHESIA MACHINE
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-Battery backup for at least 30 min
-Alarms high, med, and low priority High priority alarms may not be silenced for more than 2 min |
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DISCONNECT ALARMS MAY BE BASED ON ...
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1) low pressure
2) exhaled volume 3) carbon dioxide |
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REQUIRED MONITORS ON THE ANESTHESIA MACHINE
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-exhaled volume
-inspired O2 with a high priority alarm w/in 30 secs of O2 falling below 18% -O2 supply failure alarm -Hypoxic guard system must protect against <21% of O2 if N2O is in use -anesthetic vapor <> -pulse ox, BP, EKG |
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O2 FLUSH MUST BE...
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-present and capable of 35-75 L/min flow which does not proceed through any vaporizers
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O2 FROM THE CENTRAL SUPPLY ...
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-enters at PSI of 45-55
-DISS (diameter index safety system) *check valves are located downstream from pipeline inlet to prevent reverse flow of gases --> thereby avoiding flow of gas from machine to wall |
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HANGER YOKE ASSEMBLY
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-where O2 enters machine from E cylinder
-ensures air tight seal - orients cylinder - free floating valve - prevents retrograde gas flow - allows change of cylinders during use - min gas leak to atm if a yoke is empty - min transfilling of gases |
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PISS
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PIN INDEX SAFETY SYSTEM
-where the hanger yoke assembly is located -prevents misconnection of a cylinder to the wrong yoke |
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PISS NUMBERS
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-AIR- 1 & 5
-N2O- 3 & 5 -O2- 2 & 5 |
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CYLINDER PRESSURE REGULATOR
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-converts cylinder pressure to a constant pressure of ~ 45 psig downstream of the regulator
-**intentionally slightly less than the pipeline pressure b/c the machine will use the higher gas pressure from the central supply (45-55) preventing silent depletion of the emergency cylinder |
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TIME TO O2 CYLINDER EXHAUSTION
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-shortcut PSI left in the tank x 0.3
Remaining volume in L in an E cylinder is calculated by dividing the cylinder pressure by 2200 psi then x by 660L ex- gauge reads 1000psi 1000/2200 = 0.45 0.45 x 660 L = 300 L |
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O2 CONSUMPTION DURING MECHANICAL VENTILATION
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-O2 flowmeter rate + min ventilation
minute ventilation = TV x RR |
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O2 CONSUMPTION DURING MECHANICAL VENTILATION
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FGF = 0.5 LPM O2 & 1.0 LPM of N20
ventilator setting TV = 0.7L and RR = 10bpm = 0.7 x 10 = 7LPM 300 L left in cylinder O2 consumption 0.5 + 7 = 7.5 LPM mv 300L/7.5LPM ~ 40 min remaining |
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SPONTANEOUSLY BREATHING ... LEFT IN CYLINDER
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-what's remaining in tank/ rr
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N2O CYLINDERS
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N2O will read 745 psi until all the liquid in the cylinder has vaporized to gas
-volume of N2O cylinder cannot be determined based on the psig |
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< CRITICAL TEMP
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molecules will get close together and form a liquid
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> CRITICAL TEMP
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molecules not close together and will stay in the gaseous state
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CRITICAL TEMPS OF O2 AND N2O
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-O2 -119 C
N2O 39.5 (liquid at room temp) |
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CELCIUS CONVERSION TO FARENHEIT
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C x 9/5 + 32
37 C x 9 = 333 333/5 = 66.6 66.6 + 32 = 98.6 |
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WOODS METAL
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-a safety device that melts under excessive heat (>200F) to allow the gas to escape, preventing an explosion
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JOULE THOMPSON EFFECT
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-cooling effect once compressed gas is allowed to escape in open spaces
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E CYLINDER CHARACTERISTICS
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gas - color - psi - capacity - PISS
O2 - green - 2200 - 660L - 2 & 5 N2O - blue - 745 - 1590L - 3 & 5 air - yellow - 1900psi - 625L - 1 & 5 |
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HOOKUP OF O2 SOURCE TO ANESTHESIA MACHINE RESULTS IN 5 IMMEDIATE FUNCTIONS
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1) power outlet accessory- provides pressure to vent
2) O2 flush valve- located at machine outlet to circuit 35-75L/min 3) Pressure sensor shut off valve, when O2 supplied at 50psi it holds open this valve which allows N2O to flow to the flowmeter **this remains open as long as psi remains > 25**if it falls <25 psi N2O flow is shut off 4) Supply failure alarm system- activated when O2 falls < 28psi, alarm sounds before 25 psi (the point at which N2O flow will cease) 5) second stage pressure regulator- gas pressure is decreased to a constant pressure of 16 psi --> flow from wall varies 40-50psi **after passing 2nd stage pressure regulator, sits in "stand by" at flow control valve |
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FLOWMETERS
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-components- needle valve, indicator float, knob, stop valve
-tube is tapered with the largest diameter on top, hand calibrated and no two tubes alike -gas specific -O2 is always downstream (to the right) of all the other gases **b/c there is a decreased chance O2 will be diluted or lost |
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N2O AND O2
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-flow valves are linked mechanically so O2 cannot be set < 25%
If you ^ N2O --> O2 will ^ If you ^ O2 --> N2O will not ^ If you decrease N2O --> O2 will not decrease N2O spindle has 14 teeth O2 spindle has 29 teeth N2O rotate 2.07 x O2 will rotate once |
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VOLATILE ANESTHETICS
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-liq at room temp and atm pressure
-Energy necessary for molecules to escape form the liquid to enter gas phase is supplied as heat -heat of vaporization is the # of C req at a specified temp to convert 1 g of liq to vapor |
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VAPORIZERS
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-agent specific- precisely calibrated to compensate to changes in temp. and variations of gas flow
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VAPORIZER FLOW PATTERN
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-O2 (O2 + N2O) enter vaporizer and pass through a filter
-a relief valve exists which will open if gas flow exceeds that which is req for delivery of gas conc. on dial -there is also a temp compensating bypass valve - changes in temp are constant (room and cooling due to vaporization) --> bypass valve will open and allow gas to bypass vaporizer chamber |
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IF VAPORIZER IS TILTED > 45 DEGREES?
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-must be drained and dried or you can deliver an uncertain % of anesthetic agent
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VAPORIZER INTERLOCK
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-ensures only one vaporizer is on and gas only enters the one that is turned on
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COLORS OF IA'S
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halothane- red
iso-purple enflurane-orange sevo-yellow des-blue |
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WHAT HAPPENS IF INADVERTENTLY WRONG AGENT GETS INTO A VAPORIZER
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-HLH- higher vp agent in lower vp vaporizer --> higher <> delivered
-LHL- lower vp agent in higher vp vaporizer chamber --> lower <> delivered **you must empty, flush with 100% O2 and dry |
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TEC 6 VAPORIZER
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-made for Des b/c vp for Des is 3-4 x's that of other inhaled agents
-Boils at approx 22.8 degrees C, so the vaporizer is electrically heated to 39 deg C **If not heated, large amounts of Des req (due to MAC value 4-9x's other IA's) would cause excessive cooling of the vaporizer making conventional temp compensating mech. ineffective **pressurized, at room temp ~20 deg C des vp is near 1 atm so vaporizer is pressurized to 2 atm --> to control the amount of des output |
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BREATHING SYSTEM
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-function of any is to deliver O2 and anesthetic gases, and eliminate CO2
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CO2 WASHOUT
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-accomplished either with adequate fresh gas flow or by neutralization
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ADV OF CIRCLE SYSTEM OVER MAPLESON
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-avoids problems of pollution of the OR, anesthetic wastage, and loss of pt heat and humidity caused by high FGF req by Mapleson circuits
**circle system is a semi closed system |
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MANUAL VENTILATION AND THE APL VALVE
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-limits the amount of pressure inside the patient's lungs during manual ventilation
**if pressure reaches the setting of the APL knob, the valve opens and allows excess gas escape to the scavenging system |
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APL VALVE
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-turn to right (closing) Increases pressure
-turn to left (opening) decreases the pressure **when ventilator is on it is bypassed |
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CO2 ELIMINATION
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-circle system allows rebreathing of exhaled gases to conserve heat and humidity --> Co2 absorber
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SODA LIME VS BARALYME
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MESH same for both
METHOD OF HARDNESS - SL silica added to minimize dust - BL bound water of crstallization CONTENTS SL- 95% CaOH2, 4% NaOH, 1% KOH - BL- 80% CaOH2, 20% BaOH INDICATOR DYE - both ethyl vilolet ABSORPTIVE CAPACITY (L of CO2/ 100g granules) SL- 14-23, and BL- 9-18 |
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AMSORB
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-CaOH2 and CaCl2
**does not form compound A |
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FINAL PROD OF CO2 NEUTRALIZATION
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-carbonates + water + heat
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COMPOUND A
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-sevo interacts with strong bases in soda lime or baralyme to form degradation prod
*factors that ^ Compound A* -total gas flow rates < 1L/min - use of baralyme over soda lime - high absorbent temp - ^ <> of sevo - drying of the absorbent --> fresh soda lime, machine on all night - length of anesthetic |
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CARBON MONOXIDE PRODUCTION
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-DES > ENF > ISO --> absorbents produce CO --> increasing <> with absorbers that have not been used for 24 hours or longer
**factors that increase CO prod- use of BL > SL, increased temp in absorbers, dry absorbent, increasing anesthetic <>, length of anesthetic |
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UNIDIRECTIONAL VALVES
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-make sure they flutter on expiration and inspiration
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TIDAL VOLUME
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-volume of gas entering or leaving a patient during insp. or exp. phase time
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MINUTE VOLUME
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TV + RR
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INSP. FLOW TIME
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-beginning and end of insp. flow
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INSPIRATORY PAUSE TIME
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-period from the end of inspiratory flow to the start of expiratory flow
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INSPIRATORY PHASE TIME
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-inspiratory flow time + Inspiratory pause time
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EXPIRATORY FLOW TIME
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-beginning and end of expiratory flow
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IE RATIO
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-inspiratory and expiratory phase time
-normal- 1:2 |
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INSPIRATORY FLOW RATE
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-volume of gas per unit time that passes from the patient connection of the breathing system to the patient
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EXPIRATORY FLOW RATE
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-volume of gas per unit time returned from the patient during the expiratory phase
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RESISTANCE
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-pressure difference per unit flow across the airway *usually increases as flow increases
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COMPLIANCE
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-ratio of a change in volume to a change in pressure
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POWER SOURCE
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-compressed gas, electricity, or both
-modern piston vents no driving gas -contemporary bellows req both |
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BELLOWS
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-separates breathing system gases from driving gas
*classified by how the bellows move during EXPIRATION |
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ASCENDING (STANDING) BELLOWS
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-most common
-rise (fill) during expiration and fall (empty) during inspiration |
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DESCENDING (HANGING) BELLOWS
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-less safe
-unrecognizable pt disconnect (will fill and empty even with a disconnect) |
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TWO SETS OF GASES IN VENTS
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DRIVING GAS - outside the bellows
PATIENT GAS - inside the bellows TV = MV/RR |
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SCAVENGING SYSTEMS AND WHAT NIOSH RECOMMENDS
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-N2O- 25ppm
-halogenated agents- 2ppm -halogenated agents + N2O- 0.5ppm |
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COMPONENTS OF SCAVENGING SYSTEMS
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-gas collection assembly (tubes connected to APL and vent relief valve)
-gas disposal tubing- carries gas from interface to disposal assembly -gas disposal assembly- active most common, uses hospital suction system |
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ACTIVE SCAVENGING SYSTEM
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-positive and neg pressure relief valves protect the pt from the neg pressure of the vacuum system and positive pressure of an obstruction in the disposal system
-3L reservoir bag is present to hold excess gas until it can be removed -vacuum control valve is adjusted to 10-15 L of waste gas per min |
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PASSIVE SCAVENGING SYSTEM
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-interfaces with the hospital ventilation duct --> relies on the build up of gases in the bag to passively empty into hospital vent system
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HIGH PRESSURE SYSTEM
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-cylinders on back of machine
-45-55psi -O2 flush valve can flush up to 75L/min -hanger yoke, hanger yoke check valve, cylinder pressure reg., cylinder pressure gauge |
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INTERMEDIATE PRESSURE SYSTEM
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-receives gases at relatively low and constant pressures (35-45 psi/ pipeline pressures)
-pipeline inlets and pressure gauges, ventilator power outlet accessory, O2 flush valve, supply failure alarm system, second stage pressure regulator, flow meter valves |
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LOW PRESSURE SYSTEM
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-components distal to the flow meter needle
-flow meter tubes, vaporizers, temp compensating bypass valve, common gas outlet |
