#18 – Understands and uses Nitrous Oxide

When not to use nitrous oxide

1. Impediments to adequate breathing
2. Drug and substance abuse
3. Mental disorders
4. Pregnancy
5. Recent middle ear surgery
6. Surgical treatment to the ocular area with a gas bubble
7. Conditions where gas distention is problematic
8. Use of antidepressants, psychotropic drugs, sleep-inducing medication
9. Bieomycin sulfate therapy
10. Severe cardiac conditions
11. Cystic fibrosis
12. Unknown or dubious medical history or health status

Four situations to use nitrous

(1) Person is nervous…we respond… “I hear what you’re saying – we have developed ways to control that” (new patient typically).
(2) Scaling/root planning patients
(3) Patient appears uncomfortable during appointment
(4) Recall patient that has used nitrous in past

One of our first client centered, and therefore most important, tasks to learn in this level is how to start the client using nitrous oxide. Here are the potential benefits to our client from using nitrous oxide:

1. Decreases fear (lowers blood pressure, pulse rate, and respirations)
2. Analgesic
3. Can easily relax and cooperate
4. Time passes more quickly(slight amnesic effect)
5. Reduces gagging, saliva, and tongue movements
6. Muscles relax more less chance of cramps
7. Won’t remember as much about appointment

8. Contraindications
1. first pregnancy trimester
2. nasal obstruction
3. chemical dependency
4. recent eye surgery
5. mental illness

What advantages to us when our client is more relaxed?

1. The less chance they will move quickly and be injured
2. Treatment will go more quickly
3. We are under less strain when the client relaxes
4. Pride when the client says “its the best visit I’ve ever had to the dentist!”
5. The office atmosphere is more calm and relaxed
6. Happy clients come back and bring their friends
7. Just another way to visibly show the client that we are a modern, caring office
8. Allow us to use long well planned appointments

Is it safe?

1. Used in “modern” dentistry since 1960
2. Nitrous oxide is an inert gas that enters and leaves the bloodstream unchanged
3. The client is always conscious
4. No known allergic reactions to nitrous


1. Person can feel claustrophobic
2. Not effective for some people
3. Unmanageable children won’t cooperate
4. Chemical dependent or psychiatric care clients shouldn’t use it
5. People with colds shouldn’t use could pass on to next user
6. Can cause an upset stomach (leading to vomiting) if dosage is too high

A. First, learn some of the history of nitrous oxide. While you are discussing whether a client wants to use it or are inducing a client it is useful information to share.
1. It was discovered about 200 years ago.
2. Around 1850 Horace Wells, a dentist, was watching a stage show where a “professor” induced a volunteer from the audience with nitrous. As the man laughed, he ran his leg into the side of a table and, even though his leg was bleeding, he didn’t notice the pain.
3. This dentist then began to use nitrous in his practice. This was the first time doctors had a way to remove pain.
4. Nitrous was used at 100%. The patient was induced and before they passed out – and within a few minutes would die of asphyxiation, the leg was cut off or the tooth pulled. Then, before they smothered, they were placed on 100% oxygen and revived.
5. Later, ether and then local anesthetics like Novacaine were developed. They were easier to use and took the place of nitrous.
6. In the 1960’s dentists began to use nitrous again, but in a different way. Instead of trying to use it to deaden pain by making the patient unconscious, they used a light level to relax the patient. This light level allowed the patient to breath 3-4 times the amount of oxygen they would get in normal air (20%). There were no known reactions and no side effects.
7. Now, about 40% of dentists use nitrous.

B. What safety procedures are used?
1. Color coding won’t allow reversing the two
a. Green – oxygen
b. Blue – nitrous
1. Size and shape of the attachments is different for oxygen and nitrous oxide.
2. Flow meter to measure ventilation.
3. Variety of mask sizes
4. An alarm is attached at the secretary’s desk warns us when the oxygen runs out.
5. All exhaled nitrous oxide is sucked away from the operatory and vented out of the building. This reduces our air concentrations from about 2000 parts per million to about 25 parts per million.
6. Open operatories allow huge room air mixing.
7. Nitrous oxide monitoring.
8. Limit client talking
9. Paddle fans must be on
10. Flow meters calibrated every 5 years

C. Discussion with the client who has never used nitrous
1. Perfectly safe – no allergic reactions, the weakest of all anesthetic gases.
2. Feeling comes on in 3-5 minutes – and goes away as quickly (client can drive home safely)
3. Won’t lose consciousness – actually controls themself – if breath through nose will get sensation, goes away if breath through mouth
4. A warm, relaxed, floating sensation for most people, for some it isn’t effective, others can feel claustrophobic, recommend try it – if not like it, we’ll remove it.

D. Administering Nitrous Oxide

When you seat the client, look at his/her yellow treatment sheet. Have they used nitrous before? If they have, your questions should indicate you are familiar with their past treatment. Mrs. Brown, you’ve used Nitrous Oxide during treatment in the past. Would you care to use it today?

If this is a new client, or there is not record of nitrous in the treatment sheet, ask them differently. Mrs. Brown, (new client) have you used nitrous oxide to make your treatment more comfortable in the past? Or Mrs. Brown, (established client), in reviewing your record, I don’t see that you’ve used nitrous oxide. Would you care to use it today?

If your client asks you about it, you can say. Mrs. Brown, nitrous oxide is a totally safe method to help you be more comfortable during your treatment. There are not allergic reactions and virtually no side effects. It takes only a few minutes for you to notice the effect and it goes away quickly when we’re finished. It gives you a warm, light, relaxed, floating sensation. Your doctor will do everything else the same with or without you using it. If you would care to try it, I’ll start it. If you don’t like it, I’ll take it off and we’ll not use it again.

If the client prefers not to use nitrous, make a note of it in the remarks section of the client’s yellow treatment sheet.

If the client decides to use nitrous and they have used it in the past, plug in the lines, attach the suction to the ventline. Turn on the oxygen only, set the indicator at 6 liters, and then place the nosepiece on. If you put the nosepiece on before your turn on the gases, the client will have trouble breathing. Have the client adjust the nosepiece to fit snugly around the nose. Ask your client to make sure that no air is blowing into their eyes. Do NOT leave pt. unattended while on N2O for longer than 3-4 minutes.

Make sure the breathing bag is not over (cause excessive leakage around mask) or under inflated. Do not talk with the client. This contaminates the operatory. Use the lowest concentration of N2O possible to reduce the amount of N2O you could breathe. Remind your client to breathe in and out through the nose. If the client continues to breathe through mouth or talk, reach over and turn nitrous off and let the client breathe oxygen only. Do not say anything to the client. They may not even realize what you have done.

Many apprehensive clients prefer to use N2O during injections and the difficult parts of an appointment (tooth preperation, scaling, etc.). As soon as the difficult portion is finished, place the client on 100% O2. If your client uses the N2O throughout the appointment, when the appointment is almost over, the doctor will place the client on 100% oxygen for at least 3-5 minutes. After 5 minutes, the breathing bag only contains oxygen. Never use the oxygen flush button. You’ll know a client has the right amount of nitrous when your client:
1. Is smiling
2. Hands are relaxed
3. Comfortable, pleasant
4. Treatment is going well

Be sure to have one of the staff let you try the nitrous oxide so you understand the experience.

The dentist will say, Mrs. Brown, I’ve turned off the nitrous oxide. You’re breathing pure oxygen now. This should leave you feeling relaxed and refreshed, like you’ve had a good nap. Isn’t this a great way to have a dental treatment? If the client isn’t given enough oxygen to flush his/her system, they may develop a headache.

When you are introducing nitrous oxide to children, use some different words. Amy, Dr. Smith got laughing gas just for kids. They really enjoy it. Here’s what it looks like. (putting it up against your nose) It’s like what airplane pilots wear. All you do is breath in and out your nose for a few minutes. Some of the kids feel like they’re flying an airplane, others feel like a clown. I like to know what you’re feeling like. Most of the kids today have felt clowny. You tell me how you feel. It smells like a balloon.

If a client is getting too much nitrous oxide, you will notice one or more of these symptoms:
1. Not talk rationally
2. Uncoordinated movements
3. Uncontrolled laughing, crying
4. Uncooperative, irritable
5. Uncomfortable
6. Nausea, sweating

Your doctor will reduce the level of nitrous by 10% and monitor him/her closely. Continue further reductions of 10% per minute until your client is comfortable.

If your client loses color, begins to sweat, increases salivation, swallows frequently, or feels nauseous, place him/her on 100% oxygen immediately. There are several causes for nausea:
1. Depth of sedation
2. Length of sedation
3. Client’s emotional status
4. How recently has eaten
5. Constant changes in chair position

If your client is going to vomit, remove the nosehood. Turn the head to the side. Hold an emesis basin under the chin. When finished, put a cold compress on the forehead and replace the nosepiece and turn on 100% oxygen.

Finally, there are potential health hazards to us when nitrous is used. Spontaneous abortions, depressed blood cell formation, as well as liver and kidney dysfunction have been reported in hospital room personnel. These people are exposed in a closed room to high concentrations.

Most experts believe that exposure to 3000 hours over 10 years is a heavy exposure.

Nitrous oxide is stored in fat tissue. Therefore, the heavier a client, the more time s/he should be on 100% oxygen. Even though no studies show any damage to dental personnel, use every precaution.
1. The rooms are wide open.
2. We use an exhaust system that takes the waste nitrous out of the office.
3. Make sure the nosepiece fits well.
4. Remind the client to breath through nose.
5. Turn on the ceiling fans.
6. Place client on 100% oxygen as soon as possible.
7. Don’t talk with client.

A. Remove client from nitrous oxide
1. Start client on 100% oxygen while we still have 5 minutes left in the treatment.
2. Tell the client, You have been breathing 2-3 times the amount of oxygen that you get in room air. This will leave you feeling relaxed and refreshed, just like you had a good nap. Isn’t this a great way to sit through a dental appointment?
3. Don’t remove the nosepiece until your client feels back to normal.

Some clients may shiver as they return to normal. Cover them with a blanket. They will return to normal quickly.

B. Clean up
1. The outside of the nosepiece should be put in cold sterile solution.
2. The inside nosepiece should be statimed after each use.

C. Extremely Apprehensive Clients

1. Premedicate the night before and then 1 hour before using one of:
a. 15 30 mg Dalmain
b. 10 20 mg Valium
c. 2 mg Atavan
d. 30 mg Cerax
2. 1 Lomotil tablet 1/2 hour before appointment for those who vomit easily

D. Contra indications to using nitrous
1. History of chemical abuse
2. Nasal obstruction (mouth breather)
3. Sever psychic problems
4. Upper respiratory infection (cold, flu, etc.)
5. Mentally Challenged
6. Feelings of claustrophobia
7. Emphysema, bronchitis

E. Maintenance
1. Daily
a. Listen for any poor connection to floor connector
b. Look for any cracks or wear areas in rubber goods
c. Make sure all connections are secure
d. All tanks secure in N2O room
e. All unused cannistors covered

2. Four times per year.
a. Use a soap solution to check all rubber goods for leaks. Be sure to wash soap off completely.
b. Use a soap solution to check all connections in N2O room.

3. Every 10 years
a. Return N2O head to manufacturer to check calibration.

Your Safety

Nitrous oxide is safe for clients with good health histories. The person at risk is you. A 1980 study of 61,000 American dentists and chairside assistants indicated that women assistants exposed regularly to nitrous oxide had a 50% increase in congenital abnormalities in newborns.

In our office we use every safety device to protect you.

1. Well fitting nose pieces
2. Good staff instructions
3. Paddle fans to circulate air
4. Open operatory design
5. Scavenging system
6. Waste gas is exhausted out of the building

You have learned all the necessary safety procedures. These include:

1. Make sure the mask fits well. Don’t use 2×2’s to plug spaces, find a nose piece that fits.
2. Start and end the gas flow with O2 until the nosepiece is in position.
3. Encourage the client not to talk and to breathe in and out through the nose.
4. Use a soap solution to make sure there are no leaks in the rubber goods and connections