Anesthesia machine 4 Flashcards

1
Q

Choose the statement that BEST describes the Tec 6 vaporizer (select two):
a. it is pressurized to two atmospheres
b. it uses a flow-over design
c. it is heated to 42 degrees
d. its output is increased inside a hyperbaric chamber

A

a. it is pressurized to two atmospheres
d. its output is increased inside a hyperbaric chamber

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2
Q

The Tec 6 is different than a variable bypass vaporizer in that it

A

injects a precise amount of vaporized desflurane directly into the fresh gas flow

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3
Q

To ensure precise vaporizer output, the desflurane vaporizer heats the liquid anesthetic to ________ and pressurizes it to _______

A

39 C and 2 atmospheres

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4
Q

The Tec 6 vaporizer does not

A

compensate for changes in elevation

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5
Q

With the Tec 6, a lower ambient pressure (high altitude) requires

A

a higher setting on the dial

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6
Q

With the Tec 6, a higher ambient pressure (hyperbaric oxygen tank) requires

A

a lower setting on the dial

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7
Q

Which device will be the FIRST to detect an oxygen pipeline crossover?
a. proportioning system
b. oxygen analyzer
c. fail-safe device
d. pulse oximeter

A

b. oxygen analyzer

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8
Q

The oxygen analyzer typically resides in the

A

inspiratory limb of the breathing circuit

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9
Q

The oxygen analyzer is the final defense against

A

the delivery of a hypoxic mixture

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10
Q

The only safety device in the anesthesia machine that measures oxygen concentration is

A

the oxygen analyzer

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11
Q

If O2 consumption increases, but O2 delivery remains constant, then it’s possible

A

to create a hypoxic mixture

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12
Q

What are the three roles of the oxygen analyzer?

A

it monitors oxygen concentration (not pressure)
it can detect an oxygen pipeline crossover
it can detect a hypoxic mixture caused by a leak in the oxygen flowmeter

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13
Q

The galvanic fuel-cell oxygen analyzer must be

A

calibrated daily and the components are consumable so must be replaced over time

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14
Q

The paramagnetic device oxygen analyzer is

A

self-calibrating and has no consumale parts

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15
Q

Compared to the galvanic fuel-cell, the paramagnetic device

A

has a faster response time

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16
Q

What are the MOST critical actions to perform during an oxygen pipeline crossover? (select 2)
a. disconnect the pipeline supply
b. replace the oxygen analyzer
c. ventilate with an ambu with the auxillary oxgyen flowmeter
d. turn on the oxygen tank

A

a. disconnect the pipeline supply
d. turn on the oxygen tank

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17
Q

When the oxygen analyzer alarms, it’s best to assume

A

that a pipeline crossover has occurred until other causes can be ruled out

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18
Q

If you have a pipeline crossover, you must perform these two critical steps:

A

turn on the oxygen cylinder AND disconnect the pipeline oxygen supply

19
Q

The second step of a potential pipeline crossover is to,

A

verify that the oxygen concentration in the circuit is increasing; if not, ventilate the patient with an Ambu bag connected to a different oxygen tank & convert to a TIVA

20
Q

With a pipeline crossover, it is important to conserve tank oxygen by _________. If your machine uses oxygen as the ventilator drive gas, then convert to

A

using low flows; hand ventilation

21
Q

Select the true statements regarding the oxygen flush valve. (select 2).
a. the risk of barotrauma is minimized by ventilators with fresh gas decoupling
b. it will deliver a continuous pressure of 35-75 psi
c. excessive use can lead to awareness
d. it will cause the ventilator spill valve to close during inspiration

A

a. the risk of barotrauma is minimized by ventilators with fresh gas decoupling
c. excessive use can lead to awareness

22
Q

The oxygen flush valve provides a path for oxygen to travel from the

A

intermediate-pressure system to the breathing circuit

23
Q

Pressing the oxygen flush valve exposes the breathing circuit to oxygen flow of

A

~35-75 L/min.

24
Q

Pressing the oxygen flush valve exposes the breathing circuit to oxygen pressure of

A

~50 psi (pipeline pressure)

25
Q

Most manufacturers do not recommend using the oxygen flush valve for

A

jet ventilation- its use in this context is considered “off label”

26
Q

The gas from the oxygen flush does not pass through

A

the vaporizers which can dilute the partial pressure of the volatile agent and may lead to patient awareness

27
Q

During mechanical ventilation, the ventilator spill valve is

A

closed during the inspiratory phase

28
Q

Pressing the oxygen flush during the inspiratory phase

A

transfers pressure to the patient’s lungs leading to risk of barotrauma

29
Q

Describe what happens to the bellows and spill valve during inspiration.

A

drive gas compresses bellows
drive gas closes spill valve
fresh gas form the ventilator goes to the patient

30
Q

Describe what happens to the bellows during expiration.

A

expired gas refills the bellows
bellows fills completely
when circuit pressure >2-4 cm H2O expire gas is directed through the spill vale to the scavenger

31
Q

Methods on anesthesia machines to minimize the risk of barotrauma include

A

isolating the tidal volume delivered to the ventilator from the flowmeters and oxygen flush valve- known as fresh gas decoupling
inspiratory pressure limiter- limits the breathing circuit pressure where excess gas is vented out the scavenger

32
Q

A stuck open flush valve will result in

A

barotrauma

33
Q

What 2 functions does the drive gas on a pneumatic ventilator serve?

A

it compresses the bellows
it opens and closes the ventilator spill valve

34
Q

What is the minimum expiratory pressure needed to open the ventilator spill valve?

A

~3 cmH2o

35
Q

Select the true statements about the pneumatic ventilator bellows. (select 2)
a. a descending bellows is made safer by fresh gas coupling
b. a descending bellows cannot rise and fall with a circuit disconnect
c. a leak in the bellows may cause the reading on the oxygen analyzer to increase
d. a hole in the bellows may cause barotrauma

A

c. a leak in the bellow may cause the reading on the oxygen analyzer to increase
d. a hole in the bellows may cause barotrauma

36
Q

The bellows is classified by its movement during

A

expiration

37
Q

An ascending bellows_______ during expiration, and a descending bellows _______during expiration.

A

rises; falls

38
Q

The ___________ bellows design is generally regarded as safer

A

ascending bellows

39
Q

The ascending bellows design is generally safer because the

A

descending bellows continue to rise and fall if there is a circuit disconnect; newer descending bellows designs mitigate this risk

40
Q

A leak in the bellows creates a path between

A

the ventilator drive gas (the gas that compresses the bellows) and the gas inside the patient breathing circuit

41
Q

What is fresh gas flow decoupling?

A

tidal volume set on the ventilator is what the patient actually receives

42
Q

What is the equation for fresh gas flow coupling?

A

total tidal volume= Vt set on ventilator + FGF during inspiration - volume lost to circuit compliance

43
Q

A bellows leak could allow

A

anesthetic vapor to escape from the breathing circuit leading to risk of awareness