[Premixed 50% nitrous oxide and oxygen: theoretical recalls and practical modalities]

The concept of premixed 50% nitrous oxide and oxygen dated back to 1961 in England, where it is commercialised under the name Entonox. In France, after a so marginal use, premixed 50% nitrous oxide and oxygen now knows such a revival since we first consider the pain provoked by the cure. To use correctly premixed 50% nitrous oxide and oxygen, we need to know the main properties of the nitrous oxide. The four commercial versions, now on the market, are presented (Kalinox, Medimix, Antasol, Oxynox. Except a few contraindications, these indications are large, as well at hospital as outside. In less than 10% of the cases, side effects are possible. Conditions of administration are given in details. The limits of the technic and the particular precautions of use are precised.