Primary Outcomes

Measure: Mean Ec50% in response to rising concentration of isoproterenol

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Primary Outcomes

Measure: B2AR polymorphisms associated with albuterol responsiveness in acute asthma.

Time: ~ 1 hour following 3 doses of albuterol Q 20 min

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Secondary Outcomes

Measure: B2AR haplotypes

Time: ~ 1hr post 3 doses of albuterol

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Primary Outcomes

Description: Hospital admission was defined as the need to stay in the emergency room for more than 4 hours, due to the failure to meet the discharge criteria (PRAM score ≤ 3 and pulse oximetry, ≥ 92%)

Measure: Hospital Admission

Time: Starting at 4 hours post-treatment

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Secondary Outcomes

Description: Change in FEV1 one hour post-treatment in comparison with baseline. Spirometry was performed only in subjects older than 6 years and who could perform the maneuver properly.

Measure: Forced Expiratory Volume in the First Second

Time: One hour post-treatment in comparison with baseline

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Description: Change in the Pediatric Respiratory Assessment Measure (PRAM) score one hour post-treatment in comparison with baseline. The PRAM score is used to assess the severity of asthma attacks, it ranges from 0 to 15, and the higher the score, the greater the severity of the attack. We calculated the difference between the PRAM score measured one hour post treatment and the PRAM score at baseline (PRAM score 1 hour - PRAM score baseline). The larger the absolute value of the difference, the better the outcome (e.g., a difference of -4 indicates a better outcome that a difference of -2). minimum value of the difference (Albuterol - Higher Dose, experimental group): -8 maximum value of the difference (Albuterol - Higher Dose, experimental group): 0 minimum value of the difference (Albuterol - Lower Dose, control group): -8 maximum value of the difference (Albuterol - Lower Dose, control group): 0

Measure: Change in PRAM Score After One Hour

Time: One hour post-treatment

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Description: Albuterol determination in the plasma was carried out at at discharge or hospital admission (up to 4 hours post treatment), dosage was accomplished by High Performance Liquid Chromatography.

Measure: Albuterol Determination in the Plasma

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: Changes in glucose serum levels at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Glucose Serum Levels

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Electrocardiogram performed at baseline

Measure: Electrocardiogram at Baseline

Time: at baseline

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Description: Change in respiratory rate one hour post-treatment in comparison with baseline.

Measure: Changes in Respiratory Rate After One Hour

Time: One hour post-treatment in comparison with baseline

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Description: The need for additional therapies such as magnesium sulphate or intravenous albuterol were recorded

Measure: Need for Additional Therapies

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: Change in the Pediatric Respiratory Assessment Measure (PRAM) score at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline. The PRAM score is used to assess the severity of asthma attacks, it ranges from 0 to 15, and the higher the score, the greater the severity of the attack. We calculated the difference between the PRAM score measured at discharge or admission and the PRAM score at baseline (PRAM score discharge or admission - PRAM score baseline). The larger the absolute value of the difference, the better the outcome (e.g., a difference of -4 indicates a better outcome that a difference of -2). minimum value of the difference (Albuterol - Higher Dose, experimental group): -9 maximum value of the difference (Albuterol - Higher Dose, experimental group): 0 minimum value of the difference (Albuterol - Lower Dose, control group): -9 maximum value of the difference (Albuterol - Lower Dose, control group): 1

Measure: Changes in PRAM Score at Discharge or Hospital Admission

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Changes in potassium serum levels at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Potassium Serum Levels

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Changes in bicarbonate serum levels at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Bicarbonate Serum Levels

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Changes in respiratory rate at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Respiratory Rate at at Discharge or Hospital Admission.

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Change in pulse oximetry one hour post-treatment in comparison with baseline

Measure: Change in Pulse Oximetry One Hour Post-treatment

Time: One hour post-treatment in comparison with baseline

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Description: Changes in pulse oximetry at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Pulse Oximetry at Discharge or Hospital Admission.

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment) in comparison with baseline.

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Description: Change in heart rate one hour post-treatment in comparison with baseline.

Measure: Changes in Heart Rate After One Hour

Time: One hour post-treatment in comparison with baseline

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Description: Changes in heart rate at discharge or hospital admission (up to 4 hours post treatment) in comparison with baseline.

Measure: Changes in Heart Rate at Discharge or Hospital Admission

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: Electrocardiogram one hour post-treatment to identify possible rhythm disturbances.

Measure: Electrocardiogram One Hour Post-treatment.

Time: One hour post-treatment

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Description: Electrocardiogram at discharge or hospital admission to identify possible rhythm disturbances.

Measure: Electrocardiogram at Discharge or Hospital Admission

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: lengths of stay in the emergency room for discharged patients

Measure: Lengths of Stay in the Emergency Room

Time: one to four hours

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Description: Admission rates in patients with and without any of the following viruses detected by PCR in nasal lavage samples: Adenovirus; Bocavirus; Coronavirus; Enterovirus (Echovirus); Influenza (A H3N2, A H1N1/2009, B and C); Metapneumovirus (subtypes A and B); Parainfluenza 1, 2, 3 and 4 (subtypes A and B); Rhinovirus; Respiratory Syncytial Virus type A and Respiratory Syncytial Virus type B.

Measure: Admission Rates in Patients With and Without Any Virus Detected

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: Admission rates in patients with and without rhinovirus detected by PCR in nasal lavage samples.

Measure: Admission Rates in Patients With and Without Rhinovirus Detect

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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Description: Admission rates in patients with the Arg16Gly polymorphisms of the beta-2 adrenergic receptor (Arg16Gly, Arg16Arg and Gly16Gly genotypes).

Measure: Admission Rates in Patients With the Arg16Gly Polymorphisms

Time: at discharge or admission (up to 4 hours post treatment, minimum 1 hour, maximum 4 hours post treatment)

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