5. Nitrous II

Question 1

State the colors on the tanks of the corresponding gases

• Air
• CO2
• N2O
• O2
• N2

Answer 1

• Air= yellow
• CO2= light gray
• N2O = blue
• O2= green
• N2= black or dark gray

Question 2

What are the different safety mechanisms used for N2O tanks

Answer 2

• Pin index safety system
• Thread index safety system
• Diameter thread index safety system
• Oxygen fail fase
• Oxygen flush

Question 3

Which of the safety mechanisms previously listed isn’t used anymore

Answer 3

oxygen flush- evacuated the anesthetic gases from the system

Question 4

What is oxygen fail safe

Answer 4

The machine will not flow nitrous unless O2 is already flowing

Question 5

Pressure of N2O in the tank and pressure when delivered to the patient… Oxygen

Answer 5

N20= 750-800 psi 
-Patient= 25-50 psi 

O2= 2000 psi tank 
-Patient= 25-50 psi

Question 6

What is responsible for reducing the pressure from the tank to the patient for anesthetic gases

Answer 6

pressure reduction valve

Question 7

Difference in readings on the measurement gauges between the O2 and the N2O tanks

Answer 7

N2= Some of the gas is compressed to liquid

• The gauge detects the gas but not the liquid phase
• Gauge will not move move until the tank is nearly empty

O2- Gauge give accurate reading of the tank levels

Question 8

What is the difference between demand flow and continuous flow

Answer 8

Demand flow

• Gas release only when the patient breaths (respiratory effort)
• Inaccurate (don’t know how much air the patient is absobing)
• Inexpensive

Continuous

• Gas always flows
• Expensive

Question 9

What are the different continuous gas flow meters

Answer 9

• Ball= most common
• Rood= least accurate
• Rotameter= better
• Digital= best

Question 10

What are the sizes of the reservoir bags for kids and adults

Answer 10

kids= 1 L 
Adult= 3 L

Question 11

Reservoir bag is used to monitor

Answer 11

the patients respiration rate and depth

Question 12

Nasal hoods should be disinfected with

Answer 12

glutaraldehyde

Question 13

Scavenging system requires vacuum removal at what rate

Answer 13

> 45 L/min

Question 14

What type of valve is needed on a scavenging system in a nasal hood

Answer 14

non-rebreathing valve

Question 15

Who regulates N2O and who doesnt

Answer 15

ADA and OSHA don’t

-NIOSH and ACGIH do

Question 16

NIOSH and ACGIH N2O limits

Answer 16

NIOSH
-<25 ppm during admin

ACGIH
-Threshold limit value (TLV) 50 ppm for 8 hr time weighted average

Question 17

Potential causes of hypoxia with N2O use

Answer 17

• Miscalibrated flow meters
• Too high conc. N20
• Hypoventilation
• Diffusion hypoxia

Question 18

Preventing loss of conciousness in patients with N2O

Answer 18

• Titrate to desired level of sedation
• Physiologic monitoring
• Never leave patient unattended

Question 19

Patients are at a greater risk of emesis with N2O under what conditions

Answer 19

> 30 min >50% N2O

Question 20

Prevention of emesis for N2O

Answer 20

• Clear liquids or NPO for 6 hrs prior to sedation
• <30 min procedure
• <50% conc. N2O

Question 21

Treatment of emesis and aspiration

Answer 21

-Make sure airway is clear (emesis) + BLS and EMS for aspiration

Question 22

Treatment of bronchospasm and laryngospasm

Answer 22

Bronchospasm= albuterol inhaler (beta agonist) 
-Laryngospasm= 100% positive pressure O2 ventilaiton

Question 23

Prevention of broncho-/Laryngospasm

Answer 23

• Monitor and avoid over sedation
• Patient selection
• Suction field

Question 24

Patients shouldn’t drive or operate machinery how long after anesthesia with N2O

Answer 24

1 day

Question 25

Sedation records should include

Answer 25

• Medical Hx
• Consent
• Physiologic monitoring (before during and after procedure)
• Mode of N2O/O2 delivery
• Concentrations given

Question 26

Non-autoclavable parts of N2O sedation should be disinfected how

Answer 26

soaking in glutaraldehyde for at least 10 minutes (includes the reservoir bag)