Anesthesia Delivery System Part II

Question 1

This is the only protection against a hypoxic mixture within the low-pressure section of the pneumatic system:

Answer 1

Oxygen Analyzer

Question 2

This makes sure that All WALL-SUPPLY GAS CONNECTORS are keyed so only the O2 supply hose can be plugged into the O2 connector on the wall, in the same manner that the N2O hose into the N2O outlet:

A. PISS
B. DISS

Answer 2

Diameter-Index-Safety-System (DISS)

Question 3

The gas cylinders are keyed using a ______, so
that only the correct TANK can be attached to the corresponding YOLK on the anesthesia machine:

A. PISS
B. DISS

Answer 3

A. PISS

Pin-Index-Safety-System

Question 4

Which of the following is able to detect a hypoxic gas mixture:

A. oxygen analyzer
B. fail-safe valve
C. DISS
D. PISS

Answer 4

Oxygen analyzer

Question 5

Why are the flowmeters for air, O2, and N2O arranged in a specific order?

Answer 5

In the United States the O2 flowmeter must always be on the RIGHT, closest to the point of egress into the common gas manifold, just PROXIMAL TO THE ANESTHESIA VAPORIZER. With the O2 flowmeter in that position, most leaks will tend to selectively lose gases other than O2.

Question 6

This is designed to cut off the flow of all gases except O2 when the O2 pressure falls below a set value:

A. oxygen analyzer
B. fail-safe valve
C. DISS
D. PISS

Answer 6

B. fail-safe valve

Question 7

The fail-safe valve device is designed to cut off the flow of all gases except O2 when the O2 pressure falls below a set value, usually a about ___ psig?

A. 25 psig
B. 15 psig
C. 55 psig

Answer 7

25 psig

Question 8

What is a pumping effect?

Answer 8

Positive pressure can be transmitted back into the vaporizer during ventilation of the patient. The positive pressure can briefly cause gas to reverse flow within the vaporizer, allowing gas to periodically reenter the vaporizing chamber. The result of the pumping effect is increased vaporizer output beyond that indicated on the concentration dial.

Question 9

mapleson A-F are what type of circuit?

A. semi-open
B. closed
C. open

Answer 9

SEMI-OPEN

Question 10

Which of the MAPLESON system is accurately ranked from BEST to LEAST efficient for controlled ventilation?

A. D > B > C > A
B. B > D > C > A
C. A > B > D > C

Answer 10

Dog Bites Can Ache

Controlled: D > B > C > A

Question 11

Which of the MAPLESON system is best for controlled ventilation?

A. Mapleson A
B. Mapleson B
C. Mapleson D
D. Mapleson F

Answer 11

MAPLESON D

Question 12

Which of the MAPLESON system is best for spontaneous ventilation?

A. Mapleson A
B. Mapleson B
C. Mapleson D
D. Mapleson F

Answer 12

A. Mapleson A

Question 13

Rank the Mapleson circuits in order of efficiency for spontaneous ventilation?

A. D > B > C > A
B. B > D > C > A
C. A > D > C > B

Answer 13

(All Dogs Can Bite)

Spontaneous: A > D > C > B

Question 14

Soda lime is the most common absorber, and at most can absorb ____ L of CO2 per 100 g of absorbent:

A. 10L
B. 20L
C. 23L
D. 13L

Answer 14

C. 23L

Question 15

What gas is used to drive the bellows in an anesthesia ventilator?

A. O2
B. CO
C. CO2

Answer 15

A. O2

Question 16

During a leak test to check for the competency of a circle system, the pressure that the O2 flush can give to safely validate for absence of leaks is:

A. 15 cm H2O
B. 30 cm H2O
C. 45 cm H2O

Answer 16

B. 30 cm H2O

You should close the pop-off valve, occlude the Y-piece, and press the O2 flush valve until the pressure is 30 cm H2O. The pressure will not decline if there are no leaks

Question 17

The pressure inside the bellows MUST always be slightly higher than in the chamber outside, which is:

A. 1 to 2 cm H2O
B. 4 to 5 cm H2O
C. 5 to 10 cm H2O

Answer 17

A. 1 to 2 cm H2O

Question 18

Answer 18

READ

Question 19

Answer 19

READ

Question 20

What is the active base in CO2 adsorbents?

Answer 20

calcium hydroxide

Question 21

What is the flow rate when you use the O2 flush?

A. 35-75 L/min at 50 psi
B. 15-25 L/min at 50 psi
C. 10-15 L/min at 50 psi

Answer 21

35-75 L/min at 50 psi

Question 22

How should you adjust a variable bypass vaporizer at high altitude? Below sea level?

Answer 22

Leave the setting the same because the partial pressure of gas delivered won’t change (e.g., for sevoflurane and isoflurane).

Question 23

How should you adjust a desflurane vaporizer at high altitude? Below sea level?

Answer 23

Turn up the dial at high altitude and turn down the dial below sea level to achieve the same partial pressure that you would at sea level.

Question 24

Why can’t we use variable vaporizer with the desflurane?

Answer 24

Desflurane’s low boiling point and high vapor pressure make it unsuitable for a variable bypass
vaporizer. Misfilling a variable bypass vaporizer with desflurane could theoretically cause delivery
of a hypoxic mixture and a massive overdose of inhaled desflurane.

Low boiling point and High vapor pressure

Question 25

TRUE or FALSE

To test for leaks, a static test is performed which is testing if the circle system is pressurized and the airway pressure gauge is observed NOT TO FALL.

Answer 25

TRUE

To test for leaks, a static test is performed: the circle system is pressurized and the airway pressure gauge is observed not to fall.

To rule out obstruction or faulty valves, a dynamic test is performed, ventilating a test lung (usually a breathing bag) using the anesthesia workstation’s
ventilator, and observing for appropriate “lung” motion.

Question 26

Which bellow-type is considered safer:

A. ascending
B. descending

Answer 26

ASCENDING BELLOW

For bellows-type anesthesia ventilators, ascending bellows (bellows that ascend during the expiratory
phase) are safer than descending bellows (bellows that descend during the expiratory phase) because disconnections are readily manifested by failure of ascending bellows to refill.

Question 27

In a standard anesthesia workstation, the intermediate pressure starts from pipeline/step-down input from E cylinder to _____

A. flowmeter control valves
B. common gas outlet
C. oxygen analyzer

Answer 27

A. flowmeter control valves

The hospital’s gas pipelines are themselves of intermediate pressure (50- 55 psig), so the intermediate pressure section starts from the pipelines or from the stepped-down input from the E-cylinders, and extends up to the flowmeter control valves.

Question 28

In a standard anesthesia workstation, the low pressure system starts from flowmeter control valves to _____

A. oxygen flush valve
B. common fresh gas outlet
C. oxygen analyzer
D. pressure relief device

Answer 28

B. common fresh gas outlet

The low-pressure section begins at the flowmeter control valves, includes the flowmeters and anesthetic vaporizer, and ends at the fresh gas outlet.

Question 29

TRUE or FALSE

In a standard anesthesia workstation, the only high-pressure elements in the anesthesia machine
are the auxiliary gas tanks (E-cylinders) on the back of the anesthesia machine.

Answer 29

TRUE

The gas supply system can be divided into three sections: high-pressure, intermediate-pressure, and low-pressure.

The only high-pressure elements in the anesthesia machine are the auxiliary gas tanks (E-cylinders) on the back of the anesthesia machine. The pressure in these tanks (approximately 2000 pounds per square inch gauge [psig] for air and oxygen, 745 psig for nitrous oxide) is immediately stepped down to an intermediate pressure.

Question 30

Why is CO2 removal essential in a semi-closed system?

Answer 30

Circle breathing systems require a means of CO2 removal from the exhaled gases to avoid rebreathing and hypercapnia.

Although increasing the fresh gas inflow to high
levels can dilute out most CO2 in the circle system, this is a very inefficient way to conduct an anesthetic. Because typical gas flows through the anesthesia machine are less than minute ventilation (semiclosed system), absorption of CO2 is essential.

Question 31

Soda lime is a mixture of chemicals that contains mostly with:

A. Calcium
B. Sodium hydroxide (NaOH)
C. Potassium hydroxide (KOH

Answer 31

Calcium

Most absorbents use calcium hydroxide [Ca(OH)2] to react with the expired CO2, producing
insoluble calcium carbonate (CaCO3).

Soda lime is a mixture of chemicals that contains about 80% Ca(OH)2, also known as slaked lime, along with water and small amounts of strong base.

Question 32

What is the rate limiting step in the sequential process involving the carbon dioxide absorber reaction?

A. Step 1
B. Step 2
C. Step 3

Answer 32

Since additional CO2 cannot dissolve in
water until H2CO3 is consumed by strong base (step 2), the rate of NaOH and KOH regeneration (step 3) is the rate-limiting step. Some CO2 may react directly with Ca(OH)2, but as mentioned, this reaction is slower. Byproducts of the entire process are water and heat.

Question 33

Which of the following IS NOT a predisposing factor to develop higher concentration of COMPOUND A?

A. High-flow or closed-circuit anesthetic techniques
B. Higher concentrations of sevoflurane
C. KOH-containing absorbent
D. Higher absorbent temperatures

Answer 33

A. High-flow or closed-circuit anesthetic techniques

Several physical factors may predispose to higher concentrations of compound A in the breathing circuit, including the following:

□ Low-flow or closed-circuit anesthetic techniques
□ Higher concentrations of sevoflurane
□ Type of absorbent (KOH or NaOH-containing)
□ Higher absorbent temperatures
□ Fresh absorbent

Question 34

Which of the following volatile agent has the highest propensity to Carbon Monoxide toxicity?

A. Desflurane
B. Halothane
C. Sevoflurane
D. Isoflurane

Answer 34

From most to least propensity to CARBON MONOXIDE toxicity:

• desflurane ≥ enflurane > isoflurane&raquo_space;
  halothane = sevoflurane

Question 35

Which of the following has a higher risk in developing OR fire?

A. Barlyme
B. Sodalime
C. Lithium based absrobent

Answer 35

A. Barlyme

Avoiding the use of sevoflurane with strong base-rich absorbents (e.g., the now discontinued Baralyme), especially when desiccated, is the
best way to prevent such complications.

Question 36

ethyl violet undergoes color change around the pH:

A. below 8
B. below 10
C. below 6
D. below 7

Answer 36

B. 10

Conventional absorbents contain an indicator
dye, ethyl violet, that allows anesthesia personnel to visually assess the functional integrity of the absorbent. Ethyl violet is a substituted triphenylmethane dye that undergoes a color change around pH 10.3

As the absorbent becomes exhausted, the pH drops below 10.3 and the dye becomes purple. The color change indicates that the absorptive capacity of the material has been depleted.