The subjects will receive a 5 ml normal saline inhalation right after extubation and will be re-evaluated in 5 to 10 minutes. The ones who develop upper airway obstruction and stridor with a Downes-Raphaelly score of 2 or higher will receive 0.5 ml/kg of inhaled epinephrine 1:1000 diluted to a final volume of 5 ml with a maximum dose of 2.5 ml in children up to 4 years and 5 ml in children with 5 years and above, as recommended by the American Academy of Pediatrics. The subjects who do not show an improvement after the epinephrine treatment will then be randomized to receive 8 ml of inhaled normal saline and 0.6 mg/kg of IV dexamethasone. The dexamethasone group will receive 8 ml of inhaled NS q12hs and 0.15 mg/kg/dose of dexamethasone q6hs.

Extubation failure will be considered as a need for re-intubation during de 48 hours after extubation.

The inhaled epinephrine will be used as rescue therapy to absence of improvement. The number of inhaled epinephrine dosage used on each patient will be a measure of efficacy of budesonide or dexamethasone.

The non invasive mechanical ventilation and Heliox are rescue therapies. The number of patients treated with those rescue therapies will be a measure of efficacy of budesonide or dexamethasone.

The bronchoscopy will demonstrate the non-inflammatory causes of stridor, such as: vocal cord paralysis, granuloma formation, subglottic stenosis, cricoarytenoid joint disfunction. In these cases, neither dexamethasone nor budesonide will improve clinical conditions.