Inhalation sedation using nitrous oxide

LAUGHING GAS (nitrous oxide) is very safe and harmless. It has long been used in medicine and dentistry. The method is not yet known in Poland, hence you will certainly not have heard anything earlier about it. Inhalation sedation using nitrous oxide is especially suitable for children and adults who are very afraid of dental treatment or of injections (anaesthesia).

SEDATION is achieved by inhaling the laughing gas with the help of a mask placed over the nose. The patient then feels a very pleasant sense of bewilderment. Due to the pleasure of being in this state the patient does not feel any dread or fear. Very frequently patients (mainly children and young people) begin to dream. Their dreams are also very pleasant and usually involve a sensation of floating, flying or drifting in water, the air, on clouds or in space.

Apart from clearly improving the patient’s mood, nitrous oxide also has an anesthetising effect, thanks to which small fillings can be made without the need for an anaesthetic, as nitrous oxide alone suffices for this purpose. The advantages of using laughing gas are most evident when treating children. If you want to find out more about this form of inhalation sedation you will find a separate brochure on this subject in our waiting room or you can ask our receptionist.

Everyone can receive treatment free of fear and pain!
Feel free to familiarise yourself with our inhalation sedative technique based on a mixture of nitrous oxide and oxygen. This is a very pleasant and safe method for combating fear and pain. It is used in dentistry as well as in various other areas of medicine (e.g. ENT-therapy, gynaecology, etc.).
Inhalation sedation is a little known technique, mainly due to the fact that it only made its first appearance in 1995. In addition, compared with Poland during the communist period, dentists have adopted a more pleasant approach to their patients and show more empathy. Standards of treatment have likewise evolved. Whereas once treatment without anaesthetic was the norm, now anaesthesia is the standard.
Dental surgeries equipped with inhalation sedation apparatus certainly put great emphasis not only on the quality of treatment but also on ensuring pain-free operations.

What is inhalation sedation?
Nitrous oxide sedation can be defined as a state of physical relaxation, a pleasant feeling of bewilderment as well as a being distanced from reality as a result of inhaling a mixture of nitrous oxide and oxygen. In addition, the patient becomes susceptible to hypnotic suggestion while at the same time maintaining basic movement and consciousness. The patient always receives a large amount of oxygen (approx. 60%). Nitrous oxide is not administered independently in 100% dose, nor in pre-set doses (e.g. 66% N2O and 33% O2). Rather, the dose is adjusted in accordance with the reactions of the patient. You will find the details in the description of the method.

Indications for using N2O/O2 inhalation sedation.
- In clinical situations where the use of sedation ensures the best results.
- The patient exhibits considerable fear of any kind of treatment.
- In cases of children and adults who are afraid of needles being inserted in them.
- Strong vomiting reactions.
- Overexcitement, nervous hyperactivity.
- For long, monotonous or especially unpleasant surgical procedures, prosthetic procedures, impression taking
  in the case of people with strong vomiting reactions.
- Removal of calculus.
- Opening up teeth featuring gangrenous decomposition of the pulp
- Preparation of initial caries lesions.

Medical conditions for which inhalation sedation is the recommended choice:
- Asthma - N2O does not irritate the respiratory system. Reducing stress helps lower the risk of an attack.
  The respiratory mixture administered to the patient includes approx. 60% oxygen. This improves efficacy
  of breathing and the patient’s mental state.
- Epilepsy - reducing stress helps reduce the risk of an attack.
- Heart and circulatory diseases – N2O has no clear effect on the cardiovascular system.
- The patient receives a higher concentration of oxygen (approx. 60%). The pulse oximeter then has a reading
   of approx. 100%.
  More oxygen reaches the coronary vessels. Moreover, because there is no stress there is no increased need
  for oxygen.
- Hypertension – N2O has no effect on the vascular system. It reduces fear and stress and safeguards against
  any increase in blood pressure during surgical procedures.
- Haemophilia – in certain cases N2O can help circumvent the need for needle injections.

Contraindications for using N2O/O2 sedation.
- a cold, swelling of tonsils - obstruction of upper airways.
- First third of pregnancy.
- Mental disorders.
- Multiple sclerosis, porphyria, myasthenia gravis.
- Bronchiectasia, emphesyma.
- Alcoholism.
- Non-compliant patients.

Behaviour of patient under sedation
The first period of the anaesthesia process can be divided into three phases of sedation. Below is a description of the behaviour of the patient during sedation.

Phase 1 – a moderate state of sedation as well as a mild anaesthetic effect (5-25% N2O). The patient can feel a very slight tingling sensation in his or her fingers, cheeks, tongue, back, head and chest. The patient clearly relaxes and calms, his or pain threshold rises and both fear and nervous tension are reduced. The patient quickly and effectively reacts to instructions and answers questions. Their sense of touch, hearing and sight may be slightly impaired. Pupils react properly to light.
 

Phase 2 - dissociation and partial anaesthesia (20-55% N2O). A state of dissociation is observed - this is one of the key factors facilitating the surgical procedure. Dissociation is an unusual state which takes the form of the patient’s consciousness becoming detached to a lesser or greater extent from surrounding reality. The patient is aware of the place he or she is in and the actions being performed by the dental surgeon, but everything seems to be very distant. The patient has no power of resistance, all the more so as the state of sedation is a very pleasant sensation. Advanced states of dissociation result in the appearance of very vivid hallucinations similar to dreams. Hence patients are then also peaceful and mentally relaxed. The tingling sensation in different parts of the body intensifies. (A very characteristic feature of phase 2.) Eyelid movement is reduced. Verbal contact is still maintained. The patient reacts with delayed answers to questions or with answers unrelated to the question. Dream states occur, especially in the case of children. Adults do not so easily lose control over the situation Suggesting to the patient what the content of these dreams should be is advisable.
A feeling of floating, flying or drifting in water, air, clouds or space. (A very characteristic feature of phase 2.) In such situations the dentist can stop increasing the concentration and leave N2O at the achieved level.
Partial amnesia – the patient does not remember what happened during the operation and remembers only the dream, the contents of which he or she can tell immediately after the surgical procedure. The patient may also have a similar feeling to that of alcohol intoxication.
The patient’s sensitivity to, e.g. the pain of an injected needle, is then considerably reduced.
Physical relaxation involves the loosening of the muscles and the casual arrangement of both upper and lower limbs.
The most important sign that the patient remains in the dissociation phase is when the patient keeps his mouth wide open at the request of the dental surgeon (the Lang symptom). This is proof that the patient is still conscious.
Cough reflex functioning fully.

Phase 3 - status of being completely pain free (50-70% N2O). In this phase all of the above symptoms intensify. Often the patient suffers from total amnesia. The patient’s cough reflex is slightly impaired. The patient’s ability to open his or her mouth at the request of the dental surgeon still remains the basic controlled symptom.

Effectiveness of inhalation sedation depends on several factors. These are as follows:
The experience of the dental surgeon – the more experienced a dental surgeon is the more he or she can ensure that the patient is effectively sedated. The patient’s susceptibility to nitrous oxide - roughly 10% of patients are insensitive to the effects of laughing gas. The patient’s previous experiences - the greater the trauma suffered by patients in earlier visits, the more difficult it will be to sedate the patient. Sometimes it is impossible and the patient is recommended for surgery under general anaesthesia. The age of the patient – the younger the child the more difficult it is to sedate, owing to a lack of co-operation. The psycho-physical structure of the patient - patients (especially children) that are afraid of every action performed by the dentist frequently also refuse to take inhalation sedation. Gender – women less frequently consent to inhalation sedation, fearing loss of self control. The average effectiveness of inhalation sedation, i.e. patients who are successfully sedated – is roughly 80%.
 
N2O/O2 inhalation sedation in the dental treatment of “difficult children”. Author: Jolanta Pawlikowska-Kowalska, DDS
Children are among the most difficult patients that any clinic must deal with, and this is not only true of dental surgeries. Why are children so difficult to treat? The basic barrier facing dentists is the child’s intolerance to stress and pain. The primary trigger of stress among children is the unknown as well as those things they do know, but which, unfortunately, they consider to be painful. Coping with the first is relatively easy. The latter poses a serious problem. The tolerance of most children to pain is for all sense and purposes zero. There are obviously “polite” children who endure even painful treatment on live pulp. Children can obviously become accustomed to dental visits and slightly painful prophylactic check-ups, but eventually the child must eventually confront the real crux of the matter, i.e. the treatment itself, which they know will be painful. Well, here the problems begin. To be sure the biggest problem when treating children is choosing the right method for the child patient that removes stress and any feeling of pain. How can this be achieved? How can we make sure we don’t lose the child’s trust? Everyone copes with this problem as they can. Dental surgeons have developed their own procedural methods. In Poland, stress-free methods of treating children,, e.g. premedication through oral sedatives, still remains little known. The most popular method for Polish dentists when treating difficult children is holding the child and inserting a metal finger between the teeth. On the other hand, dental surgeons in the USA and many other western countries make use of needleless syringes, Cito-Ject and Paro-Ject syringes, Wand syringes and N2O/O2 sedation. The basic rule of thumb when treating children is to apply many methods in different combinations. With experience the dental surgeon can choose the right selection of methods. Even when all known methods are used, an operation can still fail because the child is terrified of injections. With no anaesthesia the visit comes for all sense and purposes to an end. Even when the anaesthetic is administered it does not guarantee success. Children hate the feeling of numbness of the anaesthetised tissue, which they perceive as a kind of pain. The child’s fear of painful actions due to past experiences is stronger than their trust in the dentist and this fear is often impossible to overcome. Many dentists thus prefer to carry out operations without an anaesthetic, taking the young patient by surprise.
To make the operation possible, it is important to proceed in such a way that the child’s stress is reduced to a minimum. One of the best methods for controlling stress is inhalation sedation using NO2. Combining inhalation sedation with other methods is a very good approach to combating pain. Inhalation sedation helps limit the patient’s awareness and partially reduces the pain threshold. Contact is maintained with the child at all times – this is very important from the point of view of the little patient’s safety. It is very easy to control the dose of nitrous oxide, deepening or reducing the sedation when necessary. N2O is an effective means of reducing the patient’s fear. Under the influence of the gas the child is calm, passive and indifferent to the surrounding reality. Moreover, children are highly susceptible to dream states, imagining themselves floating in water, flying by plane, by balloon, by space rocket, dancing at a ball with Cinderella, or riding in a carousel.
Before beginning the operation we carry out a preliminary examination of the child, primarily with regard to its age. Inhalation sedation is very rarely used on children below three years of age as they are uncooperative. It is very important to know whether the child has already been treated "by force", for there are some children who have suffer such serious psychological trauma that further dental treatment is only possible under general anaesthesia.
A detailed medical history should be taken in an interview with the parents regarding the child’s health. It is very important to ask them about the meals that the child has eaten. A child should refrain from eating at least two hours before the operation. Once we have obtained written consent for the operation we can familiarise the little patient with the apparatus for administering the N2O gas. It is not always possible to get the child to agree to have the mask placed over its nose. Of course, they smell nice and they get a dinosaur sticker as a reward, but that does not always suffice. When the child still resists the operation should be postponed until the next visit. They could be given a mask to take home. The process of familiarising the child with inhalation sedation is frequently a long one which may be drawn out over several visits. We are certain that devoting more time to convincing a difficult patient to take laughing gas will pay off in the end.
It is no longer necessary then to get the child fully acquainted with particular stages of treatment. Under the influence of a mix of N2O/O2, they have limited awareness of being in the dental surgery (during the dissociation phase most children are dreaming), and are indifferent to the work being performed by the dentist. It should be admitted, however, that children who have had major traumatic experiences when treated “by force” in the past are not so easily affected by nitrous oxide. In many such cases, even when in a state of bewilderment, they remain in control of the situation and are unwilling to co-operate and eagerly await the moment when the dentist reaches for the "drilling machine". The operation must then be interrupted and another attempt made at the next visit, when the child has more trust in the dentist. If no improvement is seen in later visits, then an operation under general anaesthetic should be recommended. It is important to stress in particular that the best patients for laughing gas sedation are first timers. Those children who have been treated with N2O ever since their first trip to the dentist regard the experience as pleasant and look forward to future visits. Very often, however, children come to my clinic who have been referred to me by other dentists who have tried to treat them using traditional methods without resorting to any kind of anaesthesia. In many cases they have endured treatment on several of their teeth without an anaesthesia up to the moment of the trepanation of the tooth chamber with vital pulp. After this they refuse to allow the treatment to go on.
N2O has an anesthetising effect, albeit a weak one. Nevertheless, many operations treating superficial or even medium dental caries (depending on the child’s sensitivity) can be carried out without an anaesthetic. This then considerably shortens the duration of the procedure. If the child complains about pain, I interrupt the procedure and administer an anaesthetic. After the child is suitably sedated it is possible to apply other methods for controlling pain. A number of approaches are possible, e.g. topical anaesthesia or anaesthesia with ethyl chloride, a local anaesthetic with a standard syringe, a needle-less injection, or nerve block anaesthesia. All these methods can be applied simultaneously. Using the thinnest possible needle, i.e. 0.3 mm, facilitates the work. Another fairly good method is to use a needle-less syringe – this is especially useful for anesthetising patients before infiltration anaesthesia or block anaesthesia. Administering an anaesthetic solely with a needle-less syringe is often insufficient. Using a Cito-Ject or Paro-Ject syringe or a computer guided Wand syringe often helps control the pain when administering the anaesthesia. In general, it is much easier to administer anaesthesia using laughing gas. The same is true when performing operations. In such cases children are calmer or do not move at all. Using children’s music, fairy tales in headphones also facilitates the operation since it distracts the child from the unpleasant sound of the turbine drill, the low speed drill or the sound of cracking when a tooth is extracted. Music makes the state of sedation much more pleasant. During inhalation sedation, dramatic noises and loud conversations or shouts should be avoided as it is easy to awaken the child from its dreamlike state.
In addition, inhalation sedation using N2O/O2 is very effective when carrying out short procedures that require opening up the chamber of teeth whose pulp is undergoing gangrenous decomposition. It is not easy to convince a child that "drilling" into a tooth that is causing so much suffering will not hurt. Moreover, the smell during trepanation is often unbearable. Laughing gas removes their fear of the operation, and the nose mask in turn completely cuts them off from the smell.
A very interesting effect of laughing gas is amnesia, although not all children experience this. Amnesia is very beneficial. Children simply do not remember what happened in the dentist’s chair and for many of them everything there is alien and terrifying.
Those children that are regular patients of mine and have been receiving treatment in my surgery for years eventually no longer need N2O. Those toddlers who had once been “dragged” onto the dentist’s chair in tears, become normal, self-controlled patients. However, they still need to be treated with extra special care. Some of them simply grow up to be brave patients, completely trusting their dentist and willingly accept treatment. This state of mind is achieved by gradually reducing the amount of time they spend under the influence of N2O. Initially children receive the gas for the entire duration of the operation. In subsequent visits the gas is cut off earlier and is used only until the anaesthesia is administered.
I must admit that although I do not use laughing gas with every child I cannot imagine working without it. I often decide whether or not to use N2O/O2 inhalation sedation on the spot during a check-up. Provided that the child has not eaten within two hours of the visit the gas can be administered right away. If the child clearly refuses to take the usual pain-killing methods (topical, infiltration and block anaesthesia, instead of wasting time convincing them that it really does not hurt, I persuade the child to put on the nose mask. This is a very simple and completely safe method. The dental surgeon can administer a mixture of N2O/O2 with the help of special apparatus. There are no longer any special restrictions when buying N2O, and having oxygen in the surgery is very beneficial.

Inhalation sedation and the dental surgeon
An ordinance of the Minister of Health and Social Welfare of 27 February 1998 "Regarding standards of procedure and medical procedures for providing health care in the fields of anaesthesiology and intensive therapy in health care units" does not mention inhalation sedation as a form of health care which can be provided by an anaesthesiologist. Dentists can use inhalation sedation on their own but only with suitable safe apparatus. It is very unwise for a dental surgeon to independently operate apparatus for general anaesthesia. Such apparatus may only be operated by an anaesthesiologist.
Dentists’ use of laughing gas varies from country to country, varying from extremely unfavourable attitudes in France, where N2O can only be used in hospitals, to an extremely liberal approach in the USA, where even firemen can use N2O on victims of accidents. One might ask here why Americans, normally so cautious and fearful of litigation, are so willing to allow medically trained firemen to administer N2O while the French restrict this right to anaesthesiologists. But France is an exception in Europe. Dentists in other European countries can use inhalation sedation techniques without any problem.
In Poland these two viewpoints collide. One advocate of the liberal approach to dentists’ use of nitrous oxide was the late renowned Polish anaesthesiologist Dr. Janusz Kącki. Thanks to this attitude dentists can use inhalation sedation in Poland.