Infectious acute respiratory failure in patients under 5 years of age: a retrospective cohort study

Acute lower respiratory infections in children under 5 years present a real challenge for diagnosis and treatment and are the first cause of mortality for this group of age. The study aimed to describe the characteristics of infectious acute respiratory failure due to bronchiolitis, pulmonary infection or severe acute asthma related to a virus or bacteria in this population of children under 5 years old at admission to the paediatric intensive care unit (PICU), PICU management and outcomes in order to better identify the needs of these patients. Our secondary aim was to compare the characteristics and PICU management of this population (1) depending on their age (less or more than 6 months old) and (2) depending on the pulmonary imaging (absence or presence of an alveolar condensation on the chest X-ray or lung ultrasound).

We conducted a retrospective study in two PICUs in the Ile-de-France region. We included children under 5 years old hospitalised between 1 January 2017 and 31 December 2021 due to a respiratory infection complicated by acute respiratory failure.

We included 707 patients. The median age was 3 months. On arrival, patients were oxygen-dependent with a mean fraction of inspired oxygen (FiO2) of 34% and 63% required non-invasive ventilation (NIV). During hospitalisation, more than 70% required ventilatory support by NIV and 10% by tracheal intubation. 18% required volaemic expansion and 4% vasopressors. Nearly 90% of PCRs for respiratory viruses were positive, and respiratory syncytial virus (RSV) was found in almost two-thirds of cases. Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae were frequently found. Significantly, patients aged less than 6 months old needed more NIV, had less alveolar condensation, had slightly lower oxygen requirements, a less frank inflammatory syndrome and a more frequently positive PCR for respiratory viruses.

We highlighted similarities between patients hospitalised for lower respiratory infection in PICU in France and those in Australia or Brazil. Optimal management relies mainly on NIV, oxygen therapy with FiO2 under 40% and available antibiotics. These results lead us to believe that the implementation of NIV training and equipment could help reduce mortality due to lower respiratory infections in children worldwide.