Jiaci

39 / 80

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
Introduction
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
(NO 2), fine particulate matter measuring 10 µm or less in
diameter (PM10 ) [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 dyspnea.
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 (NO2 and PM10)
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/m3); the concentration of Alternaria
alternata 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 2 test
was used to analyze categorical variables. Multiple logistic
regression was used to assess the association between daily
pollution (NO 2, PM10, and ozone) and admission to the ED
because of asthma. The independent variables were levels
of air pollutants (NO 2, PM10 , and ozone), pollen, and molds.
Admission to the ED was considered the dependent variable.
Statistical significance was set at P<.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:
PI-2347).
Results
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%) (P<.0001).
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
ß 2-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
366