Methods
Ethics statement, study design and
population
We conducted a single-center retrospective study that was approved by
our institutional ethics committee (n° S21031211000) and has been
declared to the Commission Nationale de l’Informatique et des Libertés
(CNIL) (MR-004 n° 2221599). According to the French law, formal consent
was not required for this type of study. We included children aged
<12 months hospitalized for bronchiolitis in Le Havre Hospital
between September 2018 to February 2021. Non-inclusion criteria were: an
age >12 months, a LOS <24h and multiple
hospitalizations.
Data collection and
outcomes
Children’s characteristics were collected from our institution medical
records (SILLAGE® Medical and Care Information System software). The
following reports were consulted, in order: the pediatric emergency
report, the hospitalization report and the detailed care provided
report. The data collected were as follows:
- Demographics: gender, age on admission, weight
- Comorbidities: prematurity (< 36 GA), bronchopulmonary
dysplasia, neuromuscular disease and congenital heart disease, chronic
respiratory disease (childhood asthma), passive smoking, and a
familial history of atopy (asthma, allergies).
- Parameters at the Emergency Department arrival (ED): time from onset
of symptoms to hospitalization, heart rate and Silverman score (/10),
altered general condition (yes, no), feeding (< or
> 50% of usual feeding), respiratory rate (RR), pulsed
oxygen saturation (SpO2%) in room air (>92%,
90%<SpO2% ≤92%, ≤ 90% or cyanosis), and accessory muscle
use (mild, moderate, or intense).
- Care during hospital stay: administration of bronchodilator and/or
corticosteroid therapy, food support (nasogastric tube and/or intra
veinous perfusion), oxygen support, use of ACT (at least every 48 h),
LOFR and LOS.
Statistical analysis
The clinical condition (severe, moderate, mild) as defined in the HAS5 was automatically calculated according to the
extracted data, using an interface created to optimize the data
collection process in Excel - Office 365® software (version 2004), and
based on the aforementioned algorithm. For our main objective, adequate
feeding was defined as a percentage of the daily amount of reconstituted
milk (mL) >70%; on the basis of the Schofield equation and
the latest European nutritional recommendations 10,11.
The daily amount of reconstituted milk (mL) given to exclusively
bottle-fed children was calculated on the basis of the modified Appert
standard 12. This calculation took the average growth
curve values (weight and height by sex), the caloric values per 100 mL
of reconstituted milk (first and second age) and the caloric adaptations
for infants <6 months of age (E-Table 1 ). The
LOFR was then defined as the time needed to reach a daily amount of
feeding >70% of this reference. The LOFR was only
calculated for exclusively bottle-fed children, excluding breastfed
(completely or partially) infants and those who had diversified feeding.
However, the data collected for these infants were analyzable to
investigate the factors associated with the LOS.
The usual procedure for ACT referred in our center is as follows: (1) a
physician assesses the child and (2) refers to a specialist
physiotherapist for ACT evaluation and (3) provide ACT or not regarding
the clinical conditions of the child. The evaluation for ACT is repeated
every day during hospital stay. For the present study, ACT referral
(ACT+) was defined as the realization of an ACT session at least each
48h of hospitalization. A single evaluation was not rated as an ACT
session. To distinguish the characteristics of the children that
received ACT sessions during their hospital stay for bronchiolitis, the
study sample was dichotomized according to whether at least one session
of ACT was provided every 48 hours of hospital stay by a physiotherapist
(ACT+) or not (ACT-).
Patients’ characteristics are reported as numbers (and/or percentages)
for categorical data; and as means (± Standard Deviation (SD)) or median
(InterQuartile Range (IQR)) for continuous data according to the
distribution of the variables. The normality of the distribution for
each variable was assessed using the Shapiro-Wilk test. For our main
objectives, we calculated univariable logistic regressions for the
dependent variables LOFR and LOS, including the patients’
characteristics as independent variables. For this purpose, the LOFR was
transformed into a binary variable between a short length (<1
day) and a prolonged length (≥ 1 day) based on the median LOFR of our
population. Similarly, the LOS was also transformed into a binary
variable between a short (< 3 days) and a prolonged (≥ 3 days)
length, according to the average LOS for bronchiolitis in France13,14. A multivariate logistic regression model, using
the dummy variable technique, was then calculated by including all the
variables significantly associated (p≤0.05) with each outcome, to
isolate factors independently related to prolonged LOFR and LOS. Odds
ratios (OR) and their Confidence Intervals (95%CI) were reported.
The characteristics of the children that received ACT and those who did
not were compared using the Mann-Whitney U test or Student’s t test for
continuous variables and the Fisher’s exact test or the Chi2 test for
categorical variables. A p-value ≤0.05 was considered as significant.
All the statistical analyses were performed using GraphPad Prism
9® software, version 9.0.1.