Non Invasive Positive Pressure Ventilation for Prevention of Acute Chest Syndrome in Sickle Cell Disease

Acute chest syndrome is a severe respiratory complication of sickle cell disease. The standard prevention of this dangerous complication is spirometry in wich patient is required to take deep breaths trough a little device several times a day. This treatment is compromised when pain in important or when the patient is asleep and cannot participate. The investigators hypothesised that non invasive ventilation in wich patient have no effort to take might be a better prevention than spirometry and may improve pain and quality of sleep. Children with vaso-occlusive crisis necessitating morphinic treatment will be randomly assigned with either spirometry or ventilation and the investigators will monitor for occurrence of acute chest syndrome, pain and quality of sleep.