Introduction
Bronchiolitis is one of the most common causes of admission to pediatric
intensive care units (PICUs)1. In the first year of
life, 2-3% of infants are admitted in hospital for
bronchiolitis1. Newborns and infants with severe
bronchiolitis admitted to PICUs are exposed to a high risk of being
supported with invasive mechanical ventilation. The costs of health care
support for children under 2 years of age with bronchiolitis exceeded
rate of mortality due to severe bronchiolitis in PICUs has dropped from
20% to less than 1%, in developed countries, it is usually associated
with severe cardiac and respiratory comorbidities 2-3.
After the first 48-72 hours, upper respiratory tract infection symptoms
(i.e., fever, congestion, rhinorrhea, irritability, poor feeding
development) may evolve into lower respiratory tract symptoms in about
one third of patents. These manifest as a typical bronchiolitis pattern
(i.e., cough, tachypnea, wheezing, grunting, nasal flaring, thoracic
retractions, and hyperinflation of the lungs)4. In
such clinical condition, air trapped in the alveoli is reabsorbed,
resulting in localized distal obstruction. This eventually leads to
increased work of breathing, reduction of lung compliance, ventilation
and perfusion mismatch, and hypoxemia, therefore leading to
life–threatening failure of respiratory function. In such cases, the
first-line respiratory support includes high flow nasal cannula (HFNC)
with delivery of high inspired oxygen concentration. Non-invasive
ventilation (NIV) delivered through a mechanical ventilator and
continuous positive airway pressure (CPAP) delivered through specific
devices utilizing only pressure deriving from gas flows are considered
second-line incremental respiratory treatments, reserved for
non-responder hypoxemic patients, who generally require PICU admission.
No recommendations are currently available regarding timing and modality
of the administration of different types of respiratory support for
these patients 5-6. Furthermore, there are not
evidence-based criteria to indicate when invasive ventilation should be
provided 7. Retrospective and prospective
observational studies have indicated that NIV may significantly reduce
intubation rates in infants with bronchiolitis 8-10.
However, available reports on severe bronchiolitis in critically ill
children have not evaluated different levels of positive end expiratory
pressure (PEEP) to determine which concentration provides optimal
respiratory support during helmet continuous positive airway pressure
(HCPAP) administration 11-14.
This randomized study aimed to evaluate the impact of two different
levels of PEEP during HCPAP support on the intubation rate and
requirement of mechanical ventilation in infants with severe
bronchiolitis admitted to PICUs.