Materials and Methods
Four hundred forty children aged 1-24 months hospitalized with diagnoses
of acute bronchiolitis between February 2018 and February 2019 were
included in this prospective study. The study was designed in compliance
with the principles of the Declaration of Helsinki, and approval was
granted by the Clinical Research Ethical Committee (No. 2018/1-6 dated
23.01.2018). Informed consent forms were obtained from individuals
legally responsible for the care of the patients included in the study.
Patients younger than one or older than 24 months, or with histories of
congenital heart disease, neuromuscular disease, immunodeficiency,
chronic lung disease (such as cystic fibrosis or bronchopulmonary
dysplasia), metabolic disease, or sibling death were excluded from the
study.
Marked retractions resulting from the functioning of the accessory
respiratory muscles, an increased respiration rate, and oxygen
saturation of 90% or less were regarded as severe
bronchiolitis.1 Weight-for-age z-score values of +2.00
or above were regarded as obesity, values between -1.00 and -1.99 as
mild malnutrition, scores between -2.00 and -2.99 as moderate
malnutrition, and values of -3.00 or below as severe malnutrition.
The age, sex, weight, and weight-for-age z-score of patients
hospitalized to the infant ward were recorded. Weight-for-age z-scores
were calculated using the World Health Organizations (WHO) Anthro
software. The presentation symptom, time of onset, and time elapsed
between onset and worsening of symptoms were subsequently investigated.
Data concerning type of delivery and gestational week, type of feeding
(mother’s milk only, mother’s milk plus formula, or formula only),
presence of atopy/food allergy, previous history of bronchiolitis,
history of admission to the neonatal intensive care unit (NICU), and
presence of gastroesophageal reflux disease (GERD) were also recorded.
Parental history of asthma, history of maternal smoking during
pregnancy, history of smoking in the home, parental education levels,
number of siblings, and number of individuals in the household were also
noted. Characteristics of the place of residence (rural area or urban,
type of heating, and type of accommodation) were investigated in the
environmental history. The patient’s physical examination findings, type
of feeding during the disease, oxygen requirements, bronchiolitis
clinical status, methods providing oxygen support (mask, high-flow nasal
cannula (HFNC), or intubation), and data concerning treatment were
recorded. Laboratory parameter findings such as white blood cell (WBC)
count, hemoglobin (Hb), platelet count, absolute neutrophil count (ANC),
lymphocyte count, serum C-reactive protein (CRP), and blood gas values
(pH, partial carbon dioxide pressure (pCO2), partial oxygen pressure
(pO2) and bicarbonate (HCO3)) were also recorded.
Statistical Analyses
Data were analyzed on Statistical Package for Social Sciences
Statistical Software, version 23.0 (SPSS Inc., Chicago, IL, USA).
Descriptive statistics were produced. Data were expressed as number
(percentage) or mean±standard deviation (minimum-maximum). Categorical
data were compared using the chi-square and Fisher’s exact tests. The
Kolmogorov-Smirnov test was applied to determine whether continuous data
were normally distributed. Normally distributed data were expressed as
mean±standard deviation (minimum-maximum) and were compared using the
independent two sample t test. p values <0.05 were regarded as
statistically significant.
Single variable logistic regression analysis was applied to identify
independent predictors of severe bronchiolitis development, and the
parameters determined were then subjected to multivariate logistic
regression analysis (backward LR model).