L6 Nitrous Oxide Sedation

Question 1

What is nitrous oxide made of

Answer 1

Dinitrogen monoxide (g)
Stored as a liquid

Question 2

What are properties of N2O

Answer 2

1. Analgesic (like morphine)
2. Anxiolytic
3. Colourless
4. Non-flammable
5. Slightly sweet
   odour
6. Low solubility in blood
7. Rapidly diffuses across membrane
8. Excreted unchanged from lungs

Question 3

What affects does nitrous have on BP and heart rate?

Answer 3

No change to BP (if at all a slight increase)

No effect on HR

Question 4

Where does N2O act?

Answer 4

On opioid receptors in the mid-brain - same is morphine and heroin

Descending inhibitory pathway
Altering pain processing in the spinal cord

Question 5

What do the effects of N2O feel like?

Answer 5

Alcohol

Question 6

What is the common percentage of N2O

Answer 6

40-70%

Usually used with other things as well - ex. will not be used alone for GA

Question 7

What is the onset time of nitrous?

Answer 7

2-5 minutes

Question 8

What are potential uses for nitrous?

Answer 8

Start GA
Titrate GA
Anxiolytic
Reduce pain

Question 9

What must be given in first and last 5 minutes?

Answer 9

Oxygen

Question 10

What is a general effect of N2O?

Answer 10

Calm, comfortable, relaxed, reduced fear/anxiety

Aware patient, that responds, but has a glazed look in eyes

Question 11

What are the general sensations people feel from nitrous?

Answer 11

1. tingling extremities
2. heaviness, heaven ness
3. warmth
4. Chills
5. Floating sensation
6. Vasodilation

Loss of gag reflex

Question 12

What is involved in the metabolism of N2O

Answer 12

Oxidizes cobalt enzyme of vitamin b12

– b12 required for myelin sheath synthesis

Question 13

Pressure volume problems

Answer 13

N2O pressure is 31x more than N2

N2O physically replaces N2 and increases the volume +/or pressure of that space

N2O 34x more soluble in blood, replacement of N2 faster than N2 is taken out, increasing pressure in air filled spaces

Question 14

What are some benefits of nitrous?

Answer 14

Good for long procedure, good for pain and anxiety, quick and easy to reverse, easily titratable
Still lets people have protective reflexes, with few side effects

Question 15

Is nitrous stored in body or metabolized by the liver?

Answer 15

Neither

99% eliminated through lungs without biotransformation

Question 16

What are indications for nitrous?

Answer 16

Fearful anxious patient 
Special health care need
Strong gag reflex 
Profound LA can't be obtained
Lengthy procedure

Question 17

What are contraindications for nitrous?

Answer 17

Lung issues
Phychological issues
Pregnancy
Bleomycin sulfate (a cancer med for SCC)
B12 efficiency 
Pulmonary hypertension
Severe cardiac disease
Claustrophobia 
Congestion, nasal probs
Resp tract infections
Full meal
Cystic fibrosis 
Pneumothorax, middle ear probs, eye surgery, hyperthermia

Question 18

What are the names of the nitrous machine we use?

Answer 18

Accutron or porter

Question 19

What colour is the oxygen side?

Answer 19

White/green

Question 20

What colour is the nitrous side

Answer 20

Blue

Question 21

Requirements for nitrous

Answer 21

5 cases per year in log book, re-register q5yr

Question 22

To certify in nitrous

Answer 22

6 cases and a 6 hour course

Question 23

What is the minimum oxygen percentage delivery?

Answer 23

30%

Question 24

What percentage of nitrous patients don’t receive enough sedation?

Answer 24

3%

Question 25

Why do patients not achieve enough sedation?

Answer 25

Claustrophobia Need more than the 70% nitrous system can deliver Too fearful

Question 26

Is vomiting possible from nitrous?

Answer 26

Yes, position upright, suction and assess for aspiration

Question 27

What is diffusion hypoxia?

Answer 27

After sedation N2O leaves the body relatively unaltered through the lungs. N2O will leave faster than N2 can replace it --> diluted supply of O2 and reducing O2 blood saturation This is why we need 5 mins of Oxygen

Question 28

Symptoms of acute nitrous exposure

Answer 28

``` Dizzy hard to breath headache nausea fatigue irritability loss of consciousness ```

Question 29

Chronic exposure symptoms

Answer 29

``` tingling numbness mental performance manual dexterity adverse reproductive effects ```

Question 30

What does it mean to minimize N2O pollution

Answer 30

``` Minimize talking Scavenge area of mixing unit Turn the tank off all the way cannot use any cracked stuff pressure test ```

Question 31

Office air zones for nitrous

Answer 31

1. patient zone - within 10 cm from nose 2. operator zone - 36-72 cm away from pt nose 3. operators zone - whole op with nitrous oxide use 4. office zone - all areas outside of operators served by same ventilation system

Question 32

What are the zones we're concerned about?

Answer 32

2 and 3

Question 33

What is the limit for nitrous use per day?

Answer 33

30 minutes to maintain a 25 ppm safety level