2 | MATERIAL AND METHODS
A prospective study of children aged 1–24 months who were hospitalized
with acute bronchiolitis was performed between December 2018 and May
2019. In accordance with American Academy of Pediatrics guidelines, a
diagnosis of acute bronchiolitis was based on at least two of the
following signs: chest retractions, tachypnea, and the first episode of
wheezing or rales on auscultation
following a viral upper respiratory tract infection in children aged
younger than 24 months6. The study included 179
patients with acute bronchiolitis and 80 healthy children. Inclusion
criteria were: aged 1–24 months, first wheezing episode, no previous
disease history, and no previous medication. Exclusion criteria were:
chronic disease, premature birth, birth weight < 2500 g,
malnutrition, passive smoking, proven immune deficiency, proven or
suspected acute bacterial infection, previous treatment with
bronchodilators or corticosteroids, or having symptoms for more than 7
days. On admission, the clinical severity score (CSS) for acute
bronchiolitis (i.e., a composite clinical score including
respiratory rate, retraction, wheezing, and general condition) was used
to evaluate patients, as previously described by Wang et
al .7 Each patient with bronchiolitis was classified
into one of three groups, depending on whether they had mild, moderate,
or severe bronchiolitis. Complete blood count measurements (including
white blood cells, MPV, and platelets) were recorded from the blood
samples taken on the first day of hospitalization using a BC-6800
analyzer (Mindray, Shenzhen, China). The IPF was recorded using flow
cytometry and the reticulocyte/platelet channel of an XE-5000 automated
hematology analyzer (Sysmex, Kobe, Japan) with a fluorescent dye
containing polymethrin and oxazine. The IPF is the fraction (%) of
immature platelets in the total platelet population. No standard
reference range for the IPF has been determined. Data from each patient
recorded in the emergency room included: age, sex, disease history,
medication, birth history, whether this was the first attack of
bronchiolitis, weight, vital signs (i.e., heart rate, respiratory
rate, tympanic temperature, and oxygen saturation when breathing ambient
air, which was measured using pulse oximetry and expressed as
SpO2). The control group included 80 healthy children
who attended pediatric clinics for routine health checks or
vaccinations. They had similar age/sex demographic characteristics to
the children with bronchiolitis. Complete blood counts and IPF data were
obtained from blood samples taken for routine testing of these children
at their first visit. The families of all children were informed about
the study objectives, and written informed consent was obtained before
enrollment in the study. The study protocol was approved by the Ethics
and Research Committee of Erciyes University (Kayseri, Turkey).