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.