The incidence of child fractures is around 180 per 10,000 children under 16 years old in industrialized countries. More and more hospitals, such as Nice University Hospital, are using vigilant procedural sedation for simple surgical procedures such as fracture reduction, allowing ambulatory care. This is why the investigators propose the alternative of intranasal ketamine associated with nitrous oxide inhalation in the management of children's pain. Indeed, thanks to its short duration of action and short duration of effectiveness, ketamine is already used in pediatric anesthesia and resuscitation for many years and is considered safe and effective.

The objective of this work is to evaluate the efficacy of intranasal ketamine associated with nitrous oxide inhalation in the reduction of isolated fractures from the extremity of the upper limb in children allowing optimal management.

This work will consist of research involving non-randomized, monocentric prospective interventional category 1 for duration of 18 months. Patients over 4 years of age and under 18 years, with a closed fracture isolated from the distal extremity of the upper limb, with stable hemodynamic will be included. In view of active queue of pediatric emergencies Nice University Hospital, the investigators can include 60 patients, allowing to have a representative sample of the pediatric population.

The treatment administered will be intranasal ketamine, using a tip MAD® (Mucosal Atomization Device) at a dosage of 1 mg/kg in a single administration, under continuous cardiorespiratory monitoring for 2 hours. The reduction of the fracture will be done under inhalation of nitrous oxide. The primary endpoint will be pain control during and after fracture reduction, defined by the FLACC Hetero-Assessment Pain Rating Scale. Others parameters as the evaluation of the degree of sedation, evaluation of the child's feeling of pain after the reduction, evaluation of the feasibility of the preparation and administration of the drug by the nurse will be reported.

The incidence of child fractures is around 180 per 10,000 children under 16 years old in industrialized countries (Norway, Sweden, Great Britain and France). However, the rate of fractures treated in pediatric emergencies varies according to the different sports activities and the location of the hospital. In Nice, the number of fractures of the upper limb in children is about 400 per year, because of the sporting diversity between sea and mountains to which children have access.

Most of the child's fractures are treated in operating theaters in hospitals in France. However, more and more hospitals, such as Nice University Hospital, are using vigilant procedural sedation for simple surgical procedures such as fracture reduction, allowing ambulatory care. At the University Hospital of Nice, analgesic management of simple fractures of the child, including fractures of the upper limb, combines 2 drugs: midazolam and nalbuphine intra-rectal. This therapy is used in combination with nitrous oxide inhalation for the reduction of the fracture site.

However, this treatment is not optimal: midazolam has significant side effects (respiratory depressant, hypotensive, excessive drowsiness, etc.) and the intrarectal way of administration suggests a problem of delayed action of the administered product, causing a variability of the effectiveness of the drug over time and a social problem. This is why the investigators propose the alternative of intranasal ketamine associated with nitrous oxide inhalation in the management of children's pain. Indeed, thanks to its short duration of action and short duration of effectiveness, ketamine is already used in pediatric anesthesia and resuscitation for many years and is considered safe and effective. This drug is a very interesting choice in the treatment of analgesics in surgical emergencies. However, it is not used in pediatric emergencies for excessive fear of side effects and service habits.

The objective of this work is to evaluate the efficacy of intranasal ketamine associated with nitrous oxide inhalation in the reduction of isolated fractures from the extremity of the upper limb in children allowing optimal management.

This work will consist of research involving non-randomized, monocentric prospective interventional category 1 for a duration of 18 months. Patients over 4 years of age and under 18 years, with a closed fracture isolated from the distal extremity of the upper limb, with stable hemodynamic will be included. In view of active queue of pediatric emergencies Nice University Hospital and taking into account lost sight, the investigators can include 60 patients, allowing to have a representative sample of the pediatric population.

The treatment administered will be intranasal ketamine, using a tip MAD® (Mucosal Atomization Device) at a dosage of 1 mg/kg in a single administration, under continuous cardiorespiratory monitoring for 2 hours. The reduction of the fracture will be done under inhalation of nitrous oxide.

The primary endpoint will be pain control during and after fracture reduction, defined by the FLACC Hetero-Assessment Pain Rating Scale < 4/10.

The secondary evaluation criteria will be: the evaluation of the degree of sedation during the gesture by the "University of Michigan Sedation Scale" score, the evaluation of the tolerance of the treatment in the child during and after the gesture (presence of desaturation) O2 <94%, hypersialorrhea, apnea, laryngospasm), evaluation of the child's feeling of pain after the reduction, evaluation of the feasibility of the preparation and administration of the drug by the nurse.

Inclusion Criteria:

• Male or Female Children
• Aged 4 to 17 years old
• Presenting a fracture isolated from the distal end of the upper limb with closed focus, requiring a reduction
• Fracture dating from <72h
• stable hemodynamics
• Affiliation to a social security scheme
• Signature of the authorization documents of the 2 parents or the representative of the parental authority for the participation of the child in the study
• Signature of informed consent for children over 15 years of age

Exclusion Criteria:

• Known hypersensitivity to ketamine
• History of epilepsy or known psychiatric illness
• Any child with a developing respiratory disease (asthma, laryngitis, tracheitis)
• Any child who has received an analgesic of level 2 or 3 in the 3 hours preceding the treatment in pediatric emergencies
• High Blood Pressure
• Severe Heart Failure
• polytrauma
• Open fracture
• Proven pregnancy
• Any child requiring pure oxygen ventilation.
• Nitrous oxide should not be used in situations at risk of accumulation in cavities and when its expansion could be dangerous, such as cranial trauma with alteration of the state of consciousness, maxillofacial trauma, pneumothorax, gas embolism , bullous emphysema, sinus or middle ear surgery, internal ear surgery, severe abdominal distension (eg, bowel occlusion)
• A child who has recently received an ophthalmic gas (SF6, C3F8, C2F6) used in ocular surgery as long as a gas bubble persists inside the eye and at a minimum for a period of 3 months. Severe post-operative complications may occur in relation to increased intraocular pressure