SEE EQUIPMENTS/TECH : Delivery and Airway Equipment Flashcards
What is the volume of the gases that cannot be accurately estimated from the cylinder pressure gauge?
Nitrous
With nitrous the pressure will remain
constant until the LIQUID portion of the gas is depleted.
If you’re doing a case and you suspect a pipeline cross over ,2 corrective actions that must be undertaken are?
Open the backup oxygen cylinder
Disconnect the pipeline gas
When you suspect a pipeline crossover, you disconnect the pipeline gas from the wall why?
Because the anesthesia machine will continue to draw from the higher pressure system even if the lower pressure O2 cylinder is open
If the flow of O2 is 2L/min , and the cylinder’s gauge pressure is 500 psi, how long will it last?
87 minutes
Molecular weight of N2O is
44g/mol , one mole at STP is 22.4 L
Names 3 components of the low pressure system
Common gas outlet
Flow meters
Vaporizer
Flush valve is part of which system?
Intermediate pressure system
Hanger yoke and cylinder pressure gauge is part of what system?
High pressure system
What is the purpose of the Diameter index safety system (DISS)
Prevents incorrect hose attachment.
The DISS Is required by the
American Society for TESTING and MATERIALS for an anesthesia workstation
What is the purpose of the pressure regulator on the gas machine?
Reduces cylinder pressure to a lower pressure before it enters the flow valve.
The pressure regulator decrease the variable cylinder pressure to
45-47 psig, to prevent dangerous levels to enter the flow valve.
What device reduces the pressure of gas from an E-cylinder to a usable pressure?
Regulator
A dula hanger yoke system hold 2 oxygen e-cylinder. If both cylinders are open , where will the gauge indicate the pressure?
The cylinder that has the highest pressure.
The HANGER Yoke functions?
Orients cylinders
provides a gas tight seal
Ensures unidirectional low.
The hanger yoke has a _____system
PIN index systme, in order to prevent the connection of a cylinder of one gas to a yoke intended for another.
What type of valve is an oxygen regulator?
DIAPHRAGM
Describe the design of the THORPE TUBE.
Gas specific
Tapered
Narrowest part of the bottom
Largest part on top
What is the minimum oxygen flow rate through the oxygen flow valve when the anesthesia machine is turned on?
150 ml/min
Oxygen flow valves are designed to deliver a minimum flow of
150ml/min when the anesthesia machine is on
Flow meter knobs are ____coded and _____coded
Color and touch
Ball types floats are read in the
Center of the float
Plumb types floats are read
At the top of the float
Changing the inspired gas composition from 100% O2 to 70% nitrous oxide may have what transient effect through the vaporizer?
A decrease volatile anesthetic concentration due to the higher solubility of nitrous in volatile agents. [
2 things that may occur from filling a VARIABLE BYPASS vaporizer with DESFLURANE?
The patient may receive a hypoxic mixture
The patient may receive a overdose of desflurane.
Desflurane has a _____boiling point and a ______VP
Low; high
At normal flow rate, changing the inspired gas composition from 100% O2 to 70% nitrous oxide will cause which of the following to happen to a vaporizing chamber output?
Increase until a new steady state is achieved.
The quantity of inhalational agent delivered from a vaporizer is dependent on the
Flow rate of the carrier gas through the vaporizer.
Effect of altering the carrier gas
Causes a temporary decrease in the vaporizer output followed quickly by an increase in output until a new steady state is achieved.
What are factors that affect the steady state of convential vaporizers ?
Viscosity of the Carrier gas
Density of the carrier gas
solubility of the carrier gas in the anesthetic liquids
Flow splitting characteristic of the specific vaporizer.
Concentration set on the vaporizer dial
Filling an enflurane-specific vaporizer with halothane will have what effect on anesthetic gas delivery?
40% increase in the anesthetic gas delivery, leading to anesthetic overdose.
Desflurane vaporizers have which of the following features?
Temperature regulation
separation of fresh gas flow from liquid agent
Desflurane vapor is added to
the fresh gas mixture before exiting
The Vaporizer for desflurane is called a
TEC 6 (tec ,4, 5, 7) and they are temperature compensated.
What are factors that influence variable bypass vaporizer output ?
High fresh gas flowrate through the vaporizer
intermittent back pressure for the use of PPV
Carrier gas composition
Vaporizer output is influenced by the _______. What is the significance of that ?
Carrier gas composition ; Changes the carrier gas to a one more soluble than oxygen changes vaporizer output.
2 things that can create higher than expected vaporizer output?
Using the flush valve
Positive pressure ventilation
Why are certain metals chosen for vaporizer construction?
Metal with HIGH THERMAL CONDUCTIVITY are chosen to maintain a uniform internal temperature/
What is thermal conductivity?
It is a measure of the speed with which heat flow through a substance.
What is the purpose of gas machine proportioning system?
Prevent the delivery of a hypoxic gas mixture to the patient.
What does the proportioning system do?/
Decrease the pressure of nitrous when oxygen pressure decreases proportionately to prevent a hypoxic gas mixture.
Nitrous oxide gas flow is regulated to maintain a minimum oxygen concentration of _____ by linking it with which gas?
21-25% Oxygen
Which of the following gases carries the greatest risk of creating a hypoxic mixture when delivered to the patient via a nitrous oxide-oxygen (3:1) FGF? why?
Desflurane. Because high concentration of a less-potent volatile, such as desflurane, can result in a vapor mixture that contains less than 21% oxygen even with a fully functioning proportioning system. This high concentration may become a higher percentage of total gas flows, lowering the inspired oxygen levels.
Oxygen supply pressure safety devices are
Oxygen failure cut-off valve
Pneumatic alarm
Second stage oxygen pressure regulator
Electronic alarm
Electronic flowmeters do what?
Allow the anesthetist to estimate total gas flow quantity in the event of a total electrical power outage but does not prevent a hypoxic mixture.
The oxygen supply pressure safety devices function
Ensure the delivered oxygen concentration will not fall below 19% at the common gas outlet if there is an oxygen pressure failure.
The Datex-Ohmeda 2nd stage oxygen pressure regulator is set to which of the following pressure ranges
12-19 psi
Oxygen supply low pressure sensors are designed to activate a gas whistle or electronic alarm when inlet gas pressure drops below the usual threshold?
20-35 psi
The 2000 ATSM F1850-00 standard states:
The anesthesia gas supply device shall be designed so that whenever oxygen supply pressure is reduced to below the manufacturer specified minimum, the delivered Oxygen concentration shall not decrease below 19% at the common gas outlet
Systems that warn of troubles with the oxygen supply or less the chances of hypoxemia are based on monitoring which of the following?
The pressure within the oxygen circuitry of the gas machine
Does the warning system of a oxygen supply problem ensure that oxygen is present?
NO . It is based solely on OXYGEN PRESSURE
What is the only MONITOR that can verify that oxygen is present?
Inspired oxygen analysis sensor.
Older gas machines, the pressure sensor shutoff valves operate under which of the following principles
Oxygen pressure > 20 psi is needed to maintain the nitrous oxide valve in the open position. If the oxygen supply pressure drops below 20psi the valve will shut and nitrous flow stops
Most modern gas use a proportioning safety device which
reduces the pressure of all gases, except air in the event of a loss of O2 pressure
At what pressure is the FAIL-SAFE VALVE ACTIVATED?
< 30 Psi
What is the purpose of the fail-safe device ensures that
When the oxygen pressure is lowered, the oxygen concentration will not decrease at the common gas outlet.
The loss of the oxygen pressure will result in an
Alarm at or below 30 psi of pipeline pressure.
Which gas is shut off by modern fail-safe valve?
Nitrous oxide
What literally hold open the gate so that nitrous oxide can flow through the gas machine?
Pressure in the oxygen line
What is the purpose of the fail-safe system?
Prevents delivery of a hypoxic gas mixture.
The fail-safe allows the flow of other gases only if there is
Sufficient oxygen pressure in the supply pipeline. If the oxygen pipeline pressure falls, gases such as nitrous oxide are stopped, thus preventing accidental delivery of a hypoxic mixture.
Because of the design of the ventilator spill valve, bellows ventilators have what level of intrinsic PEEP?
2-3 cm H2O
Standing bellows ventilator shave a mandatory PEEP of
2-3 cm H2O
When the bag/vent selector switch is set to vent which of the following component is taken out of line from a circle anesthetic system?
APL valve
bag
Machine prep for a patient with known or suspected MH?
Change breathing circuit
Change CO2 absorbent
Remove vaporizers
Flush machine at a rate of 10L/min for 20 minutes
During maintenance this is required?
Increased fresh gas flows.
Features of a DESCENDING bellows ventilator
Bellows continue to move upward and downward despite a patient disconnnection.
The driving gas pushes the bellow upward during inspiratory phase.
Features of a ASCENDING bellows ventilator
A ball type valve in the base of the ventilator relief valve produces 2-3 cm H2O of PEEP During ventilator use in all ascending-bellows ventilators.
In ascending bellows ventilator, scavenging ONLY OCCURS DURING
Expiratory phase.
In ascending bellows ventilator, a weighted ball produces 2-3 cm H2O of pressure when the
Patient exhales
Use of the flush valve inappropriately?
Inaprappropriate use of the flush valve delivers oxygen at a rate 25-75L/min directly into the circuit, can cause BAROTRAUMA of the lungs.
Leaks in the bellows assembly of an ascending-bellows ventilator may cause what with ventilation?
Inadequate ventilation because the driving gas is vented to the atmosphere.
Leaks in the bellows assembly of an ascending-bellows ventilator may cause what with alveolar ventilation?
Alveolar hyperinflation due to high pressure driving gas entering the patient circuit.
Leaks in the bellows assembly of an ascending-bellows ventilator may cause what with oxygen concentration?
A possible increase of the O2 concentration of the patient gas to 100% if the driving gas is oxygen .
Leaks in the bellows assembly of an ascending-bellows ventilator may cause what with Volatile concentration?
A lower than anticipated delivered volatile concentration.
A hole in the bellows can lead to
Alveolar hyperinflation
Possible barotrauma
High pressure circuits parts are
Hanger yoke
Yoke Block
Cylinder pressure gauge
Cylinder pressure regulators
Pipeline inlets and pressure gauges: H/I/L
Intermediate pressure circuits parts
ventilator power inlet H/I/L
Intermediate
Oxygen pressure failure device (fail-safe) and alarm H/I/L
Intermediate
Flowmeters valves part of H/I/L
Intermediate
Oxygen and nitrous oxide second stage regulators H/I/L
Intermediate
Oxygen flush valve H/I/L
Intermediate
The low pressure circuit includes components distal to the flowmeter needle
Valve
Flowmeters
Vaporizers
CGO
Commercial soda lime has a water content of
14-19%
Which of the following indicators is sued in CO2 absorbent?
Ethyl violet