Medical Gas Systems and Breathing Systems

Question 1

What branch of the government regulates the purity of cylinders

Answer 1

Pharmocopeia of the United States or National Formulary

Question 2

How is Oxygen manufactured?

critical temp?

what is the psi when it is stored via pipeline?

pressure and capacity of E cylinders?

Answer 2

—Oxygen

• Manufactured by fractional distilatiion of liquefied air
• Compressed gas at room temperature If refrigerated, critical temp –119*C
• Stored via pipeline with pressure of 2000 +/- 5 psi
• E cylinders have pressure 1800-2200 psi at temp 20*C with capacity 625-700 liters

Question 3

How is Nitorus manfucatured?

Critical temp?

E cylinder pressure and capacity

Answer 3

NITROUS OXIDE

• —Manufactured by heating ammonium nitrate (thermal decomposition)
• —Critical temp 36.5*C
• Since above room temp, kept liquefied; if rises above room temp, becomes gaseous
• —E cylinders have pressure of 745 psi @ temp 20*C with capacity of 1590 liters

Question 4

You have Nitrous at 600 psi, how much volume is left?

Answer 4

NITROUS OXIDE

by the time you see a decrease in psi, there is only about 400 L remaining

the only reliable way to measure how much in the cylinder is to weigh it

Question 5

How would a nonliquefied gas such as oxygen show decline in pressure?

Answer 5

A nonliquefied gas such as oxygen will show a steady decline in pressure until the cylinder is evacuated. Each cylinder, however, will show a steady decline in weight as gas is discharged.

Question 6

What is the critical temp of Air?

capacity and psi?

Answer 6

AIR

critical temp: - 140.6 C

E cylinder pressure: 1800 -2200 psi at temp 20 C with capacity of 625 - 700 L

Question 7

What is the marking on the cylinder that signifies if they are made of steal of aluminum, why is this important?

Answer 7

3AA –> STEEL

3 AL OR 3ALM –> ALUMINUM

—> safety for MRI machines

Question 8

What is DISS?

why is it made?

Answer 8

DISS (diameter index safety system)

Coupling mechanism that connects end of hose with appropriate gas outlet (color coded)

• Made to prevent incorrect hose attachment to hospital gas pipeline

Question 9

What is PISS?

What holes correlate with Air, Oxygen, and Nitrous?

Answer 9

PISS (Pin index safety system)

• E cylinders have 2 holes in cylinder valve that mate with corresponding pins in yoke in anesthesia machine
  *

Question 10

What are some samples of resistance in breathing systems

what system has the least resistance?

Answer 10

Open system has the least resistance

• Unidirectional valces/ APL valve
• Connectors
• HME/ Humidity
• Carbon dioxide absorbers
• Endotracheal tubes
• Circuit tubing

Question 11

Where is most resistance in an intubated patient?

Answer 11

connection between ETT and circuit connector/ Y-piece

Question 12

Where is the most resistance in unintubated patient?

Answer 12

EXPIRATORY VALVE IN SEMI-CLOSED SYSTEM

Question 13

How do you decrease resistance?

Answer 13

• Appropriate size ETT try to insert the LARGEST lumen appropriate for patient
• Controlled vs Spontaneous ventilation
• Use curved connectors to reduce sharp angles