This article explains the use of nitrous oxide for conscious sedation in pediatric dentistry, detailing its benefits, levels of analgesia, and administration techniques.

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Conscious sedation

Importance of nitrous oxide

• Reduce dental fear and anxiety
• Enhances child communication and cooperation
• Prevent untoward movement during dental treatment
• Reduced gagging
• Decreased number of visits
• Build a positive dental attitude
• Improved efficiency
• Improved quality of dental treatment.
• Less fatigue
• Increased productivity
• Increased trust and faith of parents and children

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Advantages

• Fast onset
• Easy administration
• Sedation level & duration can be adjusted based on the response
• Quick recovery
• Ability to communicate during procedures
• Safe
• No impact on daily activities

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Levels of nitrous oxide analgesia

The degree of analgesia is directly proportional to the concentration of nitrous oxide being inhaled.

The therapeutic range of nitrous oxide can be broadly divided into two planes analgesia and amnalgesia (amnesia along with analgesia). It is possible to further split each of these planes into two zones.

1. Analgesia

• Moderate analgesia
• Dissociative analgesia

2. Amnalgesia

• Analgesic anaesthesia
• Light anaesthesia

Zone 1: Moderate analgesia (6–25% Nitrous Oxide)

1. The clinician can maintain full contact with the patient.
2. It may also cause euphoria.
3. However, no nausea occur.
4. Psychomotor activity may be slightly affected.

Zone 2: Dissociative analgesia (26–45% Nitrous Oxide)

1. The pleasant effects of nitrous oxide are experienced by a sense of dreaminess, detachment, and lack of ability to concentrate.
2. Marked analgesia is experienced along with a slight sedative effect.
3. Marked sedation or drowsiness.
4. Slight amnesia, paresthesia with dizziness.

Zone 3: Analgesic anaesthesia (46–65% Nitrous Oxide)

1. Amnesia is more marked.
2. Loss of consciousness.
3. Nausea is more common.

Zone 4: Light anaesthesia (>66% Nitrous Oxide)

Amnesia is complete.

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Clinical signs and effects

1. General Appearance

1. The child is relaxed.
2. Few children may feel less scared & avoid eye contact.

2. Body movement and position

1. Body movements may be reduced.
2. Tense appearance of the body may be reduced.
3. Tingling in extremities and warmth in the body.
4. A child holding an object in his/her hand may drop the object.
5. Hands may fall.
6. Shoulders may relax and drop down.

3. Eye response

1. Eyeball movements reduce.
2. Slight drooping of the upper eyelid.
3. The blink rate may be reduced.

4. Expressions on the face

1. The face appears less tense and relaxed.
2. Tonicity of facial muscles & frowning reduces.
3. The child may have a smile on their face.
4. Voice changes.

5. Knowledge about surroundings

1. The child is fully aware of their surroundings.
2. Few children may begin to cry and look for their parents.

6. Cognitive ability

1. Nitrous oxide can lead to slowing of response.
2. It may even have the characteristics of a CNS stimulant.

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Technological aspects of nitrous oxide use in pediatric dentistry

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Technique of administration

1. First nitrous visit

First, the term "nitrous visit" refers to the visit during which the youngster is exposed to nitrous oxide.

Careful use of conventional behaviour management/modification techniques, such as TSD, modelling, and distraction along with TLC, will ensure the success of the first nitrous visit, which in turn is important for carrying out the treatment under nitrous oxide

Introduce the technique to parents by explaining the benefits and purpose of it.

2. Pre-sedation instructions

1. A child should not be having runny nose on the day of the procedure.
2. Avoid eating 2 hours before treatment.
3. A light meal may be consumed.
4. Avert fried or high-fat foods as well as milk and dairy products (such as pastries).
5. A child can consume water until just before the procedure.

3. Pre-administration assessment

It is important to review medical history and carry out physical assessment before administering nitrous oxide sedation to a child.

4. Preparation of the equipment

Before starting to administer nitrous oxide/oxygen to the child, a quick check of equipment should be done for proper function, flow, calibration, and fail-safe mechanism.

5. Titration

It is the process of determining the medication dose that reduces symptoms to the greatest possible degree while avoiding possible side effects.

There are two categories of nitrous oxide administration techniques:

• Slow titration or the standard titration
• Rapid titration

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1. Standard titration method

In this technique, nitrous oxide concentration is gradually increased by 10% every 2–3 minutes. The standard titration method is divided into the following steps:

• Introduction phase
• Induction phase
• Injection phase
• Maintenance phase
• Withdrawal phase

A. Introduction phase

1. Press oxygen flush to fill the reservoir bag to two-thirds of its capacity and then place the nasal hood on the child’s nose.
2. In this phase, oxygen is administered for 2–3 min in a concentration of 100% at a flow rate of 3–5 L/min.

B. Induction phase

1. In this phase, nitrous oxide concentration is gradually increased by 10% every 2–3 mins till desirable clinical symptoms are achieved is known as the “Critical Point.”
2. This is usually manifested as a hand/wrist drop, dropping off a toy or ball in the child’s palm, a relaxed appearance on the face, and reduced eyeball movements. This is usually in the range of 35–50%.

C. Injection phase

When some painful procedure has to be performed such as injection of local anesthesia or extraction of an abscessed tooth, the concentration of nitrous oxide should be increased to 50–60%, 2–3 min before the painful stimulus.

D. Maintenance phase

Once the injection has been given, the nitrous oxide concentration is again brought to the level at which the desired clinical symptoms were achieved.

E. Withdrawal phase

1. Following the dental procedure, the concentration of oxygen is increased to 100% and the concentration of nitrous oxide is decreased to zero.
2. The child is administered oxygen at this concentration for 5 min.

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2. Rapid titration method

This procedure involves starting the titration at a higher nitrous oxide concentration and lowering it progressively to the maintenance level.

The rapid titration method is divided into the following steps -

• Explosion phase
• Maintenance phase
• Withdrawal phase

A. Explosion phase

During this phase, nitrous oxide is administered at a high concentration (in the range of 55–65%) for the first few minutes, till the child begins to calm down.

B. Maintenance phase

The nitrous oxide concentration is brought down to a level at which desired clinical symptoms can be maintained.

C. Withdrawal phase

After the procedure is carried out, the child is administered only oxygen at a concentration of 100% for 3–5 min or a little longer till the child appears normal as before.

Indications for rapid titration

1. Negative or negative child.
2. Emergency treatment is to be carried out.
3. Introduction of nitrous oxide to a special child.

Discharge criteria

1. Cardiovascular function & Airway patency is satisfactory and stable.
2. The patient is easily arousable and protective reflexes are intact.
3. The state of hydration is adequate.
4. The patient can talk & sit unaided if applicable.
5. The patient can ambulate, if applicable, with minimal assistance. 
6. Responsible individual available

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Neha Kalantri is a practising dentist from Nashik.