Alfentanil Versus Sufentanil for Pain in Children During for Tracheal Suction

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