Study design and population
Among 824 infants consecutively admitted for bronchiolitis to the
Pediatric Emergency Department “Sapienza” University of Rome from 2012
to 2019, we have retrospectively reviewed clinical charts of the 130
infants who received oxygen by HFNC. Bronchiolitis was defined as the
first acute lower respiratory tract infection characterized by
respiratory distress with tachypnea, cough, retractions and diffuse
crackles on auscultation, in full term babies less than 12 months of age
[8]. Infants with prematurity, cardiopulmonary disorders,
immunodeficiency or congenital anomalies were excluded. Demographical,
clinical and laboratory data such as age, gender, breastfeeding,
cigarette smoking exposure, body weight, gestational age, days of
illness, length of hospital stay and low flow oxygen therapy before
HFNC, were systematically collected from clinical charts. On hospital
admission and just before starting HFNC, a clinical severity score (from
0 to 8) was assigned to each infant according to respiratory rate,
oxygen saturation in room air, presence of retractions and ability to
feed [9].
According to our internal protocol, patients underwent HFNC for the
following clinical indications: presence of severe retractions and/or
nasal flaring associated to respiratory rate higher than 70 breaths per
minute and heart rate higher than 150 beats per minute and/or oxygen
saturation lower than 92%. HFNC was started with a weight-based gas
flow rate, starting with 1L/Kg/min. After 15 minutes, physicians
performed a clinical evaluation and if necessary gas flow was titrated
up to 2 L/Kg and FiO2 adjusted to target
SaO2 (over 92%). A second clinical evaluation was
performed after 60 minutes and then every 3 hours over the next 24
hours. In case of progressive respiratory distress and inability to keep
SaO2 over 92% with a FiO2 60%, patients were admitted
to PICU where mechanical ventilation was started.
The study protocol was approved by Policlinico Umberto I ethic committee
(Rif. CE 2377/2012).