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Asthma Exacerbations in the Pediatric Emergency Department

J Investig Allergol Clin Immunol 2019; Vol. 29(5): 365-370

© 2019 Esmon Publicidad

doi: 10.18176/jiaci.0364


The prevalence of asthma among children in the European

Union is currently estimated to be 9.4% [1]. The incidence

of the disease continues to increase around the world [2],

generating a considerable economic burden through direct

and indirect costs in developed countries. A large part of

the costs is related to emergency department (ED) care and

hospitalization [3,4]. In Spain, asthma exacerbation episodes

account for 5% of pediatric ED visits, which may reach 10%-

15% at certain times of the year [5,6].

An asthma exacerbation can be defined as an increase

in airway inflammation that causes airflow limitation and

triggers asthma symptoms (wheezing, shortness of breath,

coughing, and chest tightness). It can be considered severe

if it requires systemic corticosteroids and/or ED care or

hospitalization [7,8].

Children are more susceptible than adults to the negative

health effects of pollutants [9,10]. In many cohorts, a positive

association has been demonstrated between exposure to

pollutants and mild to severe asthma exacerbations and has

been directly linked to reduced lung function [7,9-11].

The air pollutants most frequently associated with

severe exacerbations are daily levels of nitrogen dioxide



), fine particulate matter measuring 10 µm or less in

diameter (PM


) [12,13], ozone, and airborne pollen [14]. The

relationship between asthma exacerbation and factors such

as allergic inflammation, infection, and pollution remains

unclear [15].

The aim of this study was to describe the prevalence of

episodes of asthma exacerbation and their management in

a cohort of pediatric patients attended in an ED in Madrid,

Spain. Secondary analyses were performed to predict potential

triggers. We report on management of ED admissions for

asthma in the largest pediatric cohort analyzed to date. We

also examine the association between asthma exacerbations

and environmental factors in Spain during the last 10 years.

Material and Methods

We performed an observational, retrospective, single-

center study in the pediatric ED of Hospital Universitario La

Paz, Madrid, Spain from January 1 to December 31, 2015.

We performed a computerized search for patients based on

the key words

difficulty breathing, wheezing

, and/or



Those with a diagnosis of asthma exacerbation were enrolled

in the study. Data on each visit were collected from the ED

computer system and hospital medical records. The variables

included were sex, age, treatment received in the ED, need

for hospitalization, month of the year of admission, probable

cause of symptoms, and referral to the allergy or pneumology

department. Information on allergy tests performed during the

follow-up visits was obtained from the medical records of the

pediatric allergy department.

Pollen and mold spore counts were collected for the

study period from the Aerobiology Committee of the Spanish

Allergy and Clinical Immunology (SEAIC) website (https://

. Environmental pollution data

were retrieved from the website of the air quality section of

Madrid City Council



es/opencms/opencms/calaire). Air pollutants (NO


and PM



were monitored from Plaza Castilla station, one of the main

stations in the city (2.7 km from the hospital). We calculated

the mean daily, weekly, and monthly count during that period.

For pollen and mold data, the mean monthly concentrations of

Gramineae, Cupressaceae, and

Olea europaea

were recorded in

grains per cubic meter (g/m


); the concentration of



was recorded in spores per cubic meter.

Statistical Analysis

The analysis was based on descriptive statistics. Continuous

variables were expressed as median (IQR), and categorical

variables were expressed as frequency and percentage.ANOVA

or theWilcoxon rank-sum test was used to identify differences

between groups for continuous variables. The Pearson



was used to analyze categorical variables. Multiple logistic

regression was used to assess the association between daily

pollution (NO


, PM


, and ozone) and admission to the ED

because of asthma. The independent variables were levels

of air pollutants (NO


, PM


, and ozone), pollen, and molds.

Admission to the ED was considered the dependent variable.

Statistical significance was set at


<.05. All the analyses were

performed using SPSS R version 3.4.3, platform: x86_64-

w64-mingw32/x64 (64-bit), running under Windows 10 ×64

(build 16299).

This study was approved in its initial version by the Ethics

Committee of Hospital Universitario La Paz (code HULP:



During 2015, a total of 50 619 patients were attended in

the ED of our hospital. Of these, 2609 (5%) were diagnosed

with asthma exacerbation/bronchospasm. The distribution by

sex was 1534 boys (58.8%) and 1075 girls (41.2%) (



The children included were between 0 and 15 years old, with

a mean (SD) age of 3.59 (3.11) years.

Most cases resolved with outpatient care (78.3%), while

21.7% required admission to hospital. The mean age of

admitted patients was 3.2 (2.87) years. Two or more episodes

were registered in 607.8 (23.3%) patients, 23 of whom (0.9%)

had experienced 6-8 episodes during that year. The number of

recurrent episodes is shown by month of the year in the Table.

The most commonly used treatment was short-acting



-agonists in 85.1% of cases, followed by systemic

corticosteroids in 54.7%. Inhaled corticosteroids were used in

1.8%, and other treatments such as anticholinergics, oxygen,

and antipyretics were used in 41.7% of the sample. Up to

10.8% of the patients did not receive any treatment in the ED

owing to absence of symptoms during the medical assessment

and/or previous medication at home or in other health centers.

The main triggers of exacerbations were infections in 1841

cases (70.6%), followed by unknown factors in 748 (28.7%).

The remaining possible causes were cutaneous exposure to

allergens (0.6%) and food allergy (0.1%). Although there

was no systematic microbiological confirmation of suspected

respiratory infections, most were believed to be secondary