The main objective is to assess the efficacy of Alfentanil for pain in children treated by tracheal suction in pediatric intensive care units in France, compared to Sufentanyl, the current standard treatment.

Inclusion Criteria:

• child between 1 month and 15 years of age
• affiliation to the French social security system or equivalent
• child receiving mechanical ventilation for at least 4 hours and less than 48 hours
• ventilation to be provided for at least 8 hours
• less than 30 days in pediatric intensive care
• child under intravenous sedation
• consent of both parents
• consent of child when possible

Exclusion Criteria:

• curarized child
• ketamine treatment
• children suffering from facial and/or severe brain traumatism
• known hypersensitivity reaction to morphine or intolerance insufficiency to sufentanyl
• respiratory
• chronic obstructive pulmonary disease
• myasthenia
• treatment with morphine agonists-antagonists, or combination with MAOIs
• renal or liver disorders
• preterm birth of more than one month of life (but not at full term by corrected age)
• associated treatment or pathology contra-indicating administration of Sufentanyl epidural