Nitrous oxide sedation

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The nitrous oxide sedation is a medical method of pain - and anxiety relief , the patient laughing gas ( nitrous oxide ) is fed by inhalation. It is particularly used in dentistry and obstetrics . Nitrous oxide sedation differs from nitrous oxide anesthesia, among other things, in that it maintains consciousness and respiratory and protective reflexes .

history

Nitrous oxide ( chem. N 2 O), also known as laughing gas or nitrogen oxide, was discovered in 1772 by the English theologian , philosopher , physicist and chemist Joseph Priestley ; the first description of the analgesic effect was in 1799 by the chemist Humphry Davy , who also came from England . The first use as a pain reliever is attributed to the American dentist Horace Wells , who had a tooth extracted in 1844 while breathing nitrous oxide. A mixture of nitrous oxide and oxygen has been used as an anesthetic in clinical operations since 1868 .

The method of laughing gas analgesia to supplement local dental anesthesia was introduced in 1954 by E. Fuchs, H. Tracksdorf and P. von Vonow and then expanded between 1956 and 1968 by A. Tom and JH Klock for longer-term conservative dental treatments.

The process of nitrous oxide sedation using the sedative effect has been practiced less frequently in Germany in the past few decades (as of 2018) because the technical equipment for precise control of the sedation depth was lacking. With the advancement of technology and the associated solution to the problems, the process is again being used more and more in Germany . The process is more common in the USA, England, the Netherlands and Scandinavia .

Certification is recommended for German doctors and dentists, but not mandatory.

Effect and application

The distinction between nitrous oxide sedation and anesthesia is essential. While the patient loses consciousness during anesthesia and is dependent on artificial respiration , sedation poses fewer risks. The patient remains approachable as far as possible and retains his breathing and protective reflexes .

The procedure is used particularly in children and adults with dental phobias, the calming, gag suppressing effect can also be a decisive reason for particularly restless and anxious patients from four to six years. Furthermore, alternatives such as general anesthesia are comparatively expensive and have to be performed by an anesthetist .

Inhaled through face / nasal masks and absorbed through the lungs , dissolved in the blood and absorbed by the central nervous system and the brain , the largely inert laughing gas is practically not metabolized . The effect is developed in the CNS , the patient perceives the treatment as shorter, less painful, relaxed with less gagging and swallowing stimuli and is also more receptive to hypnosis , especially children. The gas is quickly excreted again after the end of the supply, for the most part pulmonarily .

At the start of treatment, the patient is given 100% oxygen . After one to two minutes, the nitrous oxide dosage is increased in 10% steps. Less common, especially for restless children, is the so-called “lightning initiation”, in which a mixture is administered right from the start that contains 30 to 50% of the active ingredient. In dentistry, a mixture of 30 to 50, a maximum of 70%, is common; higher amounts can increase the patient's morbidity and mortality rate. After treatment is complete, the patient is given pure oxygen for three minutes to avoid diffusion hypoxia .

In order to ensure pain-free treatment, the sedated patient is usually injected with an additional local anesthetic , since nitrous oxide alone does not sufficiently eliminate pain.

In recent years, nitrous oxide has been increasingly used as an analgesic in obstetrics and dermatology , in particular gas mixtures of 50% nitrous oxide and 50% oxygen . During the birth, the breathing mask is held by the woman giving birth and the strength and effectiveness of the analgesic is controlled, as is the breathing rate. The gas mixture is used by dermatologists, for example, as a means to relieve pain when removing tattoos and permanent make-up, as well as for laser treatments for rosacea .

Risks

Contraindications for nitrous oxide sedation consist in patients in the ASA classification in groups 3 or fall higher, and especially pregnant women, drug addicts and patients with intestinal obstruction , otitis media , mastoiditis , a recent vitrectomy , a non-treated lack of vitamin B12 and those who are undergoing treatment with bleomycin . The reason for many of these contraindications is that nitrous oxide diffuses into the cavities of the body and these can expand. There are no known cases of allergies to nitrous oxide and if the treatment is carried out correctly, if it does not exceed 4-6 hours, it is largely risk-free and the patient can carry out everyday tasks without long-lasting after-effects. The risk of diffusion hypoxia is minimized by supplying pure oxygen after the end of treatment.

However, each patient must be monitored during treatment, during which the oxygen levels, the depth of sedation, and the respiratory and cardiovascular functions are measured. Overdosing with nitrous oxide carries risks such as loss of consciousness , nausea , vomiting , and laughing spasms , but is almost impossible with today's technology, since the depth of sedation has become very directly controllable and measurable.

In the past, deaths and dangerous accidents were caused by a lack of oxygen due to human error, for example by inadvertently swapping oxygen and nitrous oxide connections.

Furthermore, according to TRGS 900, a limit value of 100 ml / m³ nitrous oxide in indoor air in Germany must not be exceeded for workplace safety. The use of so-called double mask systems and ventilation systems are recommended for this.

Individual evidence

  1. ^ Nitrous oxide textbook online: History. Retrieved November 19, 2018 .
  2. ^ Edmund Andrews: The oxygen mixture, a new anaesthetic combination. In: Chicago Medical Examiner . tape November 9 , 1868, p. 656-661 (English).
  3. ↑ H. Bergmann: The anesthesia in the tooth, mouth and jaw surgery. In: Rudolf Frey , Werner Hügin , Otto Mayrhofer (ed.): Textbook of anesthesiology and resuscitation. Springer, Heidelberg / Basel / Vienna 1955; 2nd, revised and expanded edition. With the collaboration of H. Benzer. Springer-Verlag, Berlin / Heidelberg / New York 1971. ISBN 3-540-05196-1 , pp. 599-716, here: pp. 708 f.
  4. ^ RD Sanders, J. Weimann, M. Maze: Biologic effects of nitrous oxide: a mechanistic and toxicologic review. In: Anesthesiology. Volume 109, No. 4, (October) 2008, pp. 707-722. doi : 10.1097 / ALN.0b013e3181870a17 .
  5. ↑ a b Angela Pontzen: Laughing gas as a pain reliever in childbirth. Rheinische Post , November 6, 2014, accessed on November 20, 2018 .
  6. ^ A b Frank G. Mathers: Laughing gas sedation in children very successful. DZW - Die ZahnarztWoche , accessed on November 20, 2018 .
  7. ↑ Certification according to the guidelines of the Council of European Dentists Decision 2012. Accessed on November 21, 2018 .
  8. ↑ Calming with laughing gas - old method of treatment rediscovered . In: Free Press . January 23, 2013, p. 5 .
  9. ↑ nitrous oxide sedation, "treatment as pleasant and less perceived". DZW - Die ZahnarztWoche , accessed on November 21, 2018 .
  10. ↑ a b c d F. G. Mathers: CME training: laughing gas sedation in dentistry. (PDF) ZWR - Das Deutsche Zahnärzteblatt / Thieme Verlagsgruppe , 2013, accessed on November 21, 2018 .
  11. ↑ Jesko Gärtner: Laughing gas sedation in children's dentistry. ZWP online , June 21, 2013, accessed November 21, 2018 . }
  12. ↑ Dirk H. Groene: Analgesia in aesthetic dermatology: "The implementation of nitrous oxide anesthesia is easy to learn". (PDF) Springer Medizin , March 2014, accessed on November 24, 2018 .
  13. ↑ Nitrous oxide in the dental practice. zm-online.de, November 13, 2015, accessed on November 21, 2018 .
  14. ^ A b Tanja Wolf: Laughing gas renaissance: relaxing, but not without danger. Badische Zeitung , July 23, 2012, accessed on November 21, 2018 .
  15. ↑ Wolfgang Wegschneider, Günter Naujoks, Gerhard Wahl, Barbara Mohr: Laughing gas sedation: Inhalative exposure of dental staff - final report. (PDF) BGW , February 2017, accessed on November 24, 2018 .