#18 – Nitrous Oxide Administration

One of your first client centered, and therefore most important, tasks to learn in this level is how to set up 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. Doesn’t notice pain as much
  3. Can more easily relax and cooperate
  4. Time passes more quickly
  5. Reduces gagging, saliva, and tongue movements
  6. Muscles relax more ‑ less chance of cramps
  7. Won’t remember as much about appointment

What advantages to us when our client is more relaxed?

  1.  The less chance they will move 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. Allows us to use long well planned appointments

Is it safe?

  1. Use 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. Groups not to use –      a. chemical dependent or psychiatric care clients,      b. people with colds – can’t breathe through the nose,      c. pregnant women,      d. middle ear infections (pressure could damage tympanic membrane),      e. detached retina (pressure could cause blindness),      f. congestive heart failure,      g. tuberculosis,      h. multiple sclerosis
  5.  Can cause an upset stomach (leading to vomiting) if dosage is too high ‑ Be careful of conversation in operatory

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 in 1793 by Joseph Priestly, and English scientist.
  2. On December 10, 1844 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. Dr. Wells had the exhibitor induce him with nitrous oxide while a fellow dentist pulled his tooth.  It was easier and he began using it in his practice.
  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 Novocaine 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 virtually no side effects.
  7. Now, about 40% of dentists use nitrous.

What safety procedures are used?

  1. Color-coding won’t allow reversing the two –    a. Green ‑ oxygen,   b. Blue ‑ nitrous oxide
  2. Size and shape of the attachments is different for oxygen and nitrous oxide
  3. You can’t give less than 20% oxygen.  The system won’t let you.  We never go less than 50% nitrous in our practice.
  4. Since a tank of nitrous will last 2 1/2 times as long as an oxygen tank, the nitrous will stop when the oxygen stops.
  5. An alarm is attached at the secretary’s are to warn us when the oxygen runs out.
  6. 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.

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 themselves ‑ if breath through nose will get sensation, goes away if breathe 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

Administering Nitrous Oxide

* Overhead paddle fans should always be on when nitrous is in use.

*The dentist is the only person to turn on the nitrous

When you seat the client, look at his/her yellow treatment sheet. Have they used nitrous before?  If they have, your question 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 no 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 combination of gases designed to help you relax during the treatment.”

If the client prefers not to use nitrous make a note of this 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 vent line.  Go to your doctor.  Tell him/her that your client would like to use nitrous oxide.  Turn on the oxygen, turn on the suction within the green zone, and then place the nosepiece on and check that it seals the nose well. If you put the nosepiece on before you turn on the gases, the client will have trouble breathing.  Ask your client “Are you comfortable?” If not, readjust the nosepiece or have the client do so. When the client is comfortable, ask the doctor to turn on the nitrous oxide and adjust the concentration.

If the client decides to use nitrous and hasn’t worked with it before, use this procedure.  Turn on the oxygen and set them at 4 1/2 liters O2.  Hold the nasal inhaler up so the client can see it and put it on your nose lightly and say, “Mrs. Brown, this piece fits over your nose like this, and you breathe through it.”  Place the inhaler over the client’s nose and ask the client to adjust it for comfort.

Say the following to your client.  “______ although N20 is completely safe for you, there are some health concerns for those of us that are exposed every day.  For our safety, we ask you not to breath through your mouth or talk, since this would let N20 escape into the room where your doctor or I would breathe it.  Is this okay with you?  Here, let me place the nosepiece.  Go ahead and adjust it so it’s comfortable.  (you make sure the nosepiece makes a good seal.)  Remember, lips together, breathe through your nose.  No talking, deep “breaths”.

If the client talks or breathes through her mouth, give her one warning.  Then switch to 100% 02 and let your dentist know (don’t say anything to your client)

After your doctor has set the level of nitrous oxide at 2 1/2 liters you should stay with the client to monitor his/her reactions. Memorize the following speech.  It is designed to provide your client all the information they need while keeping them from talking, which pollutes our air and slows their uptake of nitrous oxide.

“Mrs. Brown, be sure to breathe in and out through your nose.  That whooshing sound you hear is the used gas you exhale being removed from the room and then from the office.  Although nitrous oxide is harmless to you, it could be a problem for us if we inhaled it for several hours everyday.  Everyone responds to nitrous oxide a little differently.  The first thing you will probably notice is that the tips of your fingers or your toes will feel a little tingly.  Next, you’ll notice a warm, floaty, fuzzy, relaxed, nice feeling.  Everyone has their own level at which they feel the best. If you get too little nitrous oxide, you’ll just feel normal.  If you get too much it will make you feel like you’re going to float right out of the room. We have started you at a low dose.  You may not notice any change at this level.  Remember to breathe in and out through your nose.  Can you tell a difference yet?”  Stay with the client until the doctor comes.  Try not to talk with them.

If your client doesn’t notice a change after 3 minutes, your doctor will increase the nitrous ½ liter and decrease the oxygen ½ liter.  Wait 3 minutes.  If no change, go to 3L N2 O and 3L O2.  Never give more than 50% nitrous oxide.  You’ll know a client has the right amount of nitrous when your client:

  • Is smiling
  • Hands are relaxed
  • Comfortable, pleasant
  • Treatment is going well

Make sure the breathing bag is not over (cause excessive leakage around mask) or under inflated.  Make sure the exhaust tube monitor is in the green zone.  This is the correct amount of suction.  Do not have a conversation with the client.  This contaminates the operatory.  Remind your client to breath 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 and leave the room.  Do not say anything to the client.  They may not even realize what you have done.

Anytime you offer clients N2O, offer them a movie or music also.  The sounds help block out the sound of the drill.  The movie or music will help distract your client from what the doctor is doing.

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. Never allow a client to leave the operatory if they are groggy.

Always leave the client on oxygen for at least 5 minutes.

When you are introducing nitrous oxide to children, use some different words. “Amy, doctor ______ 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 which 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:

  • Not talk rationally
  • Uncoordinated movements
  • Uncontrolled laughing, crying
  • Uncooperative or angry
  • Uncomfortable
  • Nausea, sweating
  • Constant opening and closing of the mouth

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, stop nitrous, flush ambu bag with 100% oxygen, 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 nasal 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 100% oxygen. Even though no studies show any damage to dental personnel, use every precaution.

  • The rooms are wide open
  • Use an exhaust system that takes the waste nitrous out of the office.
  • Make sure the nosepiece fits well.  There are different sizes.
  • Remind the client to breathe through nose.
  • Turn on the ceiling fans
  • Place client on 100% oxygen as soon as possible.
  • Don’t talk with the client. This allows them to breathe out N2O, both contaminating the operatory and decreasing the effectiveness of the N2O.

Removing client from nitrous oxide

  1. The dentist will start client on 100% oxygen while they 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,” and at least 3 minutes of oxygen only have been used.
  4. Clients who have been on N2O for over an hour may shiver for a few minutes.  This is due to vasodilation.  Cover the client with a blanket for a couple minutes and reassure them they are okay.     Some clients may shiver as they return to normal.  Cover with a blanket.  They will return to normal quickly.

Clean up

  • The nasal inhaler should be statimed after every use.
  • The inside nosepiece should be statimed after every use.

Extremely Apprehensive Clients

Premedicate the night before and then 1 hour before using one of:

  1. 15 ‑ 30 mg Dalmain
  2. 10 ‑ 20 mg Valium
  3. 2 mg Atavan
  4. 30 mg Cerax

Plus 1 Lomotil tablet 1/2 hour before appointment for those who vomit easily

Contra‑indications to using nitrous

  1. History of chemical abuse
  2. Nasal obstruction (mouth breather)
  3. Severe psychic problems
  4. Upper respiratory infection (colds, flu, etc.)
  5. Retarded
  6. Pregnancy
  7. Feelings of claustrophobia
  8. Emphysema, bronchitis

Monitoring badge: Once every 6 months one staff member will wear a monitor to check our level of exposure.  Currently the National Institute of Occupational Safety and Health recommends 25ppm while the American Conference of Governmental Industrial Hygienists sets a safe threshold of 50ppm.



  1. Listen for any poor connection to floor connector
  2. Look for any cracks or wear areas in rubber goods
  3. Make sure all connections are secure
  4. Four times per year – Use a soap solution to check all rubber goods for leaks.  Be sure to wash soap off completely.
  5. Every 10 years – Return N20 head to manufacturer to check calibration


  1. “Dr. _______ got this mainly for kids.  They really have fun with it.”
  2. “Some of the kids feel like clowns, some feel like they’re flying an airplane.  I like to know whether you’re a pilot or a clown, so tell me when you know.”
  3. Show the child the nosepiece on your nose first.  “This is what you breathe through.  It looks like what pilots or scuba divers wear.”

When you have read and understand this section, tell your doctor. He will let you try the N2O.  This is the best way to understand its effect.  Have your doctor take you to a heavy 50‑50 or even 60‑40 range so you can experience the uncomfortable “buzz” of too much N2O.  Now go to pure O2 with the nitrous off.  Remove the inhaler after 30 seconds.  Notices that you can talk ok, but you’ll still feel lightheaded.  At this stage it may not wear off quickly enough for you to drive.  Now put the inhaler back on and breathe O2 for another 4 minutes.  Notice that you have now lost the sensation.

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.

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 nosepiece that fits.
  2. Start and end the gas flow with oxygen 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

Nitrous Oxide Safety

We have spent most of this section discussing how to keep the client from polluting our air.  Now we’ll discuss the other potential sources of contamination.

  •  High pressure hose connections to the gas tanks
  • Hose connections to the wall connectors
  • Hose connections to the floor mounts
  • Hose connections to the mobile delivery system
  • Hose connections to the scavenging mask
  • Rubber breathing bag

Use a soap solution once each week on all those connections.  If you see bubbles, then the connection is leaking.  Rinse the soap off when you finish since the soap could reduce the life of the rubber goods.

Signed off by ____________________          Date ___________