Medical Gas Systems

Question 1

Purity of cylinders is regulated by

Answer 1

Pharmacopeia of US

Question 2

Cylinders are inspected

Answer 2

Q 10 years by DOT

Question 3

Regulates storage/transportation of compressed gas

Answer 3

DOT

Question 4

Standards for manufacturing/delivering compressed gas

Answer 4

Compressed gas association

Question 5

Publishes minimum safety/performance standards for anesthesia machine

Answer 5

ANSI - American National Standards Institute

ASTM - American Society for Testing and Materials

Question 6

Oxygen E-Cylinder

Answer 6

2000 psi

625-700L

Question 7

Nitrous Oxide E-Cylinder

Answer 7

CT 36.5* (kept liquefied)
745 psi
1590 L
—> must be weighed

Question 8

Air E-Cylinder

Answer 8

*Same as Oxygen

Blended O2+N2O

Question 9

Cylinders marked 3AA, 3AL, 3ALM

Answer 9

Do not bring in MRI

Question 10

DISS

Answer 10

End of hose—> gas outlet in pipeline

*safety precaution

Question 11

PISS

Answer 11

E-Cylinders: 2 holes in cylinder valve —> corresponding pins in yoke in anesthesia machine

Question 12

O2 Pin index position

Answer 12

2+5

Question 13

Air Pin Index Position

Answer 13

1+5

Question 14

Nitrous Oxide Pin Index Position

Answer 14

3+5

Question 15

Sources of resistance

Answer 15

APL valve
Connectors
HMEs/Humidity
CO2 Absorbers
ET tubes
Circuit Tubing

Question 16

Breathing system that adds least resistance

Answer 16

Open system (insufflation)

Question 17

Location of most resistance in intubated pt

Answer 17

Connxn btwn ETT—> circuit connector/Y-piece

Question 18

Location of most resistance in unintubated pt

Answer 18

Expiratory valve in semi-closed system

Question 19

Open systems

Answer 19

No reservoir bar, rebreathing, CO2 neutralization or valves

• insufflation
• open drop ether

Question 20

Open drop methods used today

Answer 20

Pediatric mask induction with mask not on face —> blowby

Question 21

Semi-open systems

Answer 21

Gas reservoir, corrugated tubing, APL, common source of fresh gas
=mask on face
FGF > MV, no rebreathing

Question 22

Circuit changes classes based on

Answer 22

FGF rates

Question 23

Semi open systems

Answer 23

Mapleson systems

Question 24

Semi closed systems

Answer 24

=Mask on face
No room air inspired 
FGF < MV
Unidirectional, inspiratory/exp limb
CO2 absorber

Question 25

Closed system

Answer 25

APL closed

Gas flow = pt uptake (CO2 absorbers used)

Question 26

Best for spontaneous ventilation

Answer 26

Mapleson A

Question 27

Mapleson B

Answer 27

Reqs 2X MV of FGF (prevent rebreathing)

Question 28

FGF requirement = NO rebreathing

Answer 28

250 mL/min

FGF > Alveolar ventilation

Question 29

Mapleson Circuits: Controlled Ventilation

Answer 29

D>B>C>A

“Dead Bodies Can’t Argue”

Question 30

Mapleson Circuits: Spontaneous Ventilation

Answer 30

A>D>C>B

All Dogs Can Bite

Question 31

Most common semi-closed system used today

Answer 31

Circle system

Question 32

Closed system

Answer 32

FGF is 150 - 500 mL/min
Anesthetic agents contained in system, not vented
Closure of APL valve (rebreathing gases)

Question 33

Disadvantages of closed system

Answer 33

Unpredictable (gas % and O2)