This is a therapeutic, randomized, single center, two parallel-arm trial comparing pain control via "MEOPA" (equimolar mixture of nitrous oxide and oxygen) in one arm versus "Hypnosis + MEOPA if needed" in the second arm.

The primary objective is to compare the two study arms in terms of efficacity for pain control according to the FLACC (Face Legs Activity Cry Consolability Observational Tool) behavioural scale.

The secondary objectives of this study are to compare the two study arms in terms of:

• Efficacity for pain relief during suturing according to other validated scales (a visual analog scale (VAS), the EVENDOL (Evaluation Enfant Douleur) scale);
• the duration of the procedure, the time between the start of the care process for pain (hypnosis or nitrous oxide) and the beginning of the suture;
• the amount of nitrous oxide administered;
• the conditions under which suturing takes place, in terms of (i) the general conditions of implementation, (ii) the need to use physical restraint, (iii) failure of the procedure and the need to resort to supplementary means of anesthesia, (iv) satisfaction of the operator and his/her perceived ease of operations, (v) satisfaction of the parents;
• the behavior of the patient during removal of the suture;
• the conditions under which suture removal takes place;
• complications related to the used treatments.

Inclusion Criteria:

• The patient was informed about the implementation of the study, its objectives, constraints and patient rights
• The legal representative of the patient must have given free and informed consent and signed the consent
• The patient must be affiliated with or beneficiary of a health insurance plan
• The patient is available for 15 days of follow-up
• The patient is consulting in the emergency department for a wound requiring the completion of a suture and for which the operator considers that the use of nitrous oxide is necessary and possible.

Exclusion Criteria:

• The patient is participating in another interventional study
• The patient has participated in another interventional study in the last 3 months
• The patient is in an exclusion period determined by a previous study
• The patient and/or his/her parents (or legal representative) refuses to sign the consent
• It proves impossible to correctly inform the patient and / or his/her parents (or legal representative)
• The patient has a contra-indication (or an incompatible drug combination) for a treatment required in this study (MEOPA): intracranial hypertension, impaired consciousness, pneumothorax, high rate oxygen-dependence, facial trauma preventing mask application.
• The patient has a condition that makes hypnosis impossible: e.g. encephalopathy, deafness, communication disorders, does not speak French
• Suture requiring surgical exploration or an operating room, or general anesthesia or an ears-nose-throat, orthopedic or visceral surgeon (e.g. wound of the oral cavity, abdominal or thoracic penetrating wound, finger or palm wound requiring exploration by an orthopaedist)
• Fractures associated with wound
• Use of level II/III analgesics before the beginning of pre-suture care support