Fifty to 60% of children admitted to a pediatric intensive care unit (PICU) are placed under invasive mechanical ventilation (MV) at least once during their stay. After extubation, about 30% of these patients will experience respiratory distress due to upper airway obstruction (RDUAO), and about one-third of these cases will require re-intubation. Treating this RDUAO extends the length of stay in the PICU.

Pre-extubation corticosteroid therapy has been validated in adults as a preventive treatment for the occurrence of RDUAO. However, the lack of robust data in pediatrics has not allowed for a consensus on the benefit of its use in children on MV in the PICU.

The investigators propose to conduct a randomized, multicenter, double-blind, placebo-controlled study evaluating the effect of intravenous dexamethasone (IV-DXM) before extubation on the incidence of RDUAO in children.

Inclusion Criteria:

• Patients intubated with an endotracheal tube with or without a cuff,
• Aged from 2 days post-term to 6 years,
• On mechanical ventilation for at least 36 hours,

And meeting the following extubation criteria:

• Extubation planned by the medical team
• Fraction of inspired oxygen (FiO2) ≤ 45%,
• Oxygen saturation measured by pulse oximeter ≥ 95% or appropriate according to the pathology,
• Positive end-expiratory pressure (PEEP) ≤ 8 cmH2O,
• Peak inspiratory pressure ≤ 22 cmH2O or presence of cough.
• Affiliated with a social security system,
• Collection of informed consent from the parental authority, by both parents or the legal guardian(s).

Exclusion Criteria:

• Refusal of consent by at least one parent or by the legal guardian(s),

• Patient with a contraindication to IV-DXM:

  • Uncontrolled local or general infection,
  • Active viral infections (hepatitis, herpes, chickenpox, shingles),
  • Live vaccines,
  • Severe coagulation disorders,
  • Ongoing gastrointestinal bleeding,
  • Known hypersensitivity to IV-DXM or one of its excipients.

• Patient participating in another interventional study involving human subjects or being in the exclusion period following a previous study involving human subjects, if applicable,

• Patient receiving State Medical Aid,

• Patient on long-term NIV,

• Known upper airway pathology (UAP) before intubation or at the time of extubation,

• History of UAP surgery within the month preceding inclusion,

• Any situation deemed incompatible with the child's participation in the trial at the discretion of the investigating physician,

• Decision to limit or stop therapeutic interventions.

• Premature patients aged less than 40 weeks of gestation

• Newborns aged less than 2 days after post-term birth