Nasal spray could replace needles for sickle cell pain emergencies

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age 18 to 75 years old; * Sickle-cell patient. * Signs of a vaso-occlusive crisis (migratory bone pain, which may occur in the limbs, spine, thorax, pelvis, skull) or crisis known as such by the patient; * Severe pain (NRS ≥ 6/10) on admission to the ED; * Registered with the social security scheme or his beneficiaries (except AME) * Signature of free and informed consen. Exclusion Criteria: * Strong opioids received in the previous 6 hours; * Pregnancy or breastfeeding; * Woman not menopausal nor sterile without effective contraception (HAS criteria) * Oxygen saturation below 93%; * Patients who cannot cooperate because of a State of agitation or a Cognitive impairment * Unable to communicate; * Unable to do self-assessment; * Allergy or intolerance to opiates or nitrous oxide. * Abuse or addiction to opioids * Liver insufficiency * Renal insufficiency * Severe asthma or chronic obstructive bronchopulmonary disease * Pulmonary disease necessitating oxygen * Presence of seriousness signs: * All respiratory seriousness signs * all neurologic signs or consciousness impairment (coma Glasgow scale under 15) * hyperthermia over than 39°C * Signs of intolerance of acute anemia * Signs of hemodynamic failure * Known organ failure (renal insufficiency, pulmonary high blood pressure) * A description by the patient of a non usual crisis. * Current treatment with nasal vasoconstrictors is ongoing * Head injury with suspicion of high intracranial pressure * Severe thoracic trauma or decompensated respiratory insufficiency * Contraindications of intranasal administration: * Facial trauma * Nose or sinusal surgery in the previous 6 months before inclusion * Chronic nose and upper airway alteration (ex. facial malformation) * Acute nose and upper airway alteration (ex. Epistaxis, acute respiratory infection, sinusitis). * Contraindication to nitrous oxide * Contraindication to morphine * Patient's refusal to participate in the study. * Previous inclusion in the study of less than 14 days.