Anesthetic Delivery Systems: Prodigy Flashcards
(41 cards)
what are two components of the circle system test on an anesthesia machine? Between what two machine components does the circle system test?
the circle system test evaluates the circle breathing system from the common gas outlet to the y-piece and consists of two parts, the leak test and the flow test.
what is the most common critical incident in anesthesia?
breathing circuit disconnections which most commonly occur at the y-piece
which are considered safer on the anesthesia machine, ascending or descending bellows?
ascending (standing) bellows are considered safer than descending (hanging)
in the event of a circuit disconnect, ascending bellows will fail to rise whereas descending bellows will continue to descend due to gravity and ascend during inspiratory phase
how is the leak test performed on an anesthesia machine?
closing the pop-off valve, occluding the y-piece and evaluating for a drop in pressure after pressurizing the circuit to 30 cm H2O using the flush valve
what anesthesia machine alarms are based on the circuit pressure?
disconnect and high pressure alarms
how is the flow test performed on an anesthesia machine?
flow test checks the integrity of the unidirectional valves by removing the y-piece and breathing through each individual hose to observe the movement of each valve
on an anesthesia machine, what components are found in the low pressure system?
flowmeters, CO2 absorber, scavenging system, unidirectional valves, ventilator fresh gas delivery tubing to the breathing circuit and the breathing hoses
what components are found in the intermediate pressure system?
pneumatic part of the master switch, pipeline inlet connections and pressure indicators, the gas power outlet, oxygen flush valve, oxygen pressure failure devices and flow control valves
where does the oxygen flush receive its gas supply?
O2 flush receives an unmetered O2 supply from the cylinder pressure regulator or the pipeline inlet at a flow rate between 35-75 L/min
when is use of the O2 flush control valve contraindicated in a mechanically ventilated patient?
should never be used when there is no outlet for excess gas pressure to escape to avoid barotrauma.
when the patient is in the inspiratory phase of mechanical ventilation when the inspiratory valve is open to the patient but there is no vent for gases to escape
three functions of the hanger-yoke assembly on the anesthesia machine?
orients the gas cylinder
provides for unidirectional gas flow
provides an air-tight seal
how does a variable-bypass vaporizer work?
splits the fresh gas flow into two parts
one portion enters the vaporizing chamber where it becomes saturated with anesthetic agent
the other enters the bypass chamber and does not come into contact with the anesthetic agent
by controlling the amount of gas that enters the vaporizing chamber, the amount of anesthetic agent delivered to the patient can be controlled
is the Tec-6 vaporizer a variable-bypass vaporizer?
No
tec-6 vaporizer is heated to 39C and pressurized to 2 atm
no fresh gas flows through the sump
which vaporizer is electrically heated?
desflurane
the vaporizers for other contemporary gases are temperature compensated and have a variable-bypass, flow-over design
what is the function of the bimetallic strip in a contemporary vaporizer?
temperature sensitive and expands and contracts in response to ambient temperature changes to alter the total gas flow between the vaporizing and bypass chambers
if the temp of the liquid decreases, it will allow more gas flow into the vaporizing chamber to compensate for the decreased vapor pressure of the cooled liquid
what color is the CO2 absorbent pH indicator ethyl violet when it is exhausted?
purple
what is the pumping effect and when might it occur?
intermittent back pressure caused by positive pressure ventilation or use of the oxygen flush valve results in elevated vaporizer output
more prominent with low flows, low vaporizer dial settings, low levels of anesthetic in the vaporizer chamber, high respiratory rates and high PIP
what should you avoid using a desiccated CO2 absorbent with desflurane?
prolonged exposure of desflurane or isoflurane to desiccated CO2 absorbent can result in the degradation of the anesthetic with the resulting production of carbon monoxide
increased temperature and higher doses of anesthetic agent both increase the amount of carbon monoxide produced
the inhaled anesthetic that produces the greatest amount of carbon monoxide is desflurane
which gas flowmeter should be positioned last in the anesthesia manifold?
O2 should always be positioned last to reduce likelihood that a leak in one of the flowmeters would allow O2 to escape and lower the inspired O2 concentration
pressing the oxygen flush valve allows oxygen to bypass what components?
opens flow directly from the oxygen pipeline or first stage regulator to the common gas outlet bypassing all switches, valves, flowmeters and vaporizers
when an anesthesia machine is connected to a pipeline gas supply should the backup cylinder valves be open or closed?
closed
a pipeline pressure failure would be detected earlier and to prevent pressure variations in the pipeline from draining oxygen from the cylinders
how much does an oxygen E-cylinder hold?
660 L, 2200 or 1900 psi
how much oxygen does a D cylinder hold?
412 L, 2200 or 1900 psi
how much N2O does an E cylinder hold?
1590 L, 750 psi
