Helium-oxygen Gas Mixtures Delivered by a High Flow Nasal Cannula in Bronchiolitis

Respiratory syncytial virus associated bronchiolitis is a leading cause of global infant
morbidity and mortality [1], yet care remains largely supportive. Several recent studies show
that a helium-oxygen gas mixture (heliox) improves outcomes in children with moderate to
severe bronchiolitis [2-5, 7]. Heliox is a safe, inert gas with no biological effects and
very low density [6]. By improving laminar flow, heliox improves gas exchange in conditions
where airway resistance is increased, such as asthma, croup and bronchiolitis [6].

Recent data shows that infants with moderate to severe bronchiolitis have a reduced length of
hospital stay when heliox is delivered via facemask or CPAP, as compared to heliox via nasal
cannula [2]. Limitations to this study include the small number of patients (84/319 [26%])
who tolerated the facemask therapy and the fact that nasal cannula heliox was delivered at
low flows (3 LPM). Oxygen is increasingly being delivered with a heated, humidified, high
flow nasal cannula (HFNC) system to infants with moderate to severe bronchiolitis in our
PICU. To date, there are no definitive randomized controlled trials that show the HFNC system
is an effective treatment in bronchiolitis. However, there are several retrospective,
prospective and pilot interventional studies showing clinical improvement in this patient
population treated with the HFNC system [8-11]. We hypothesize that delivering heliox via a
heated, humidified, high flow nasal cannula will be well tolerated, safe and effective.

Specific Aim #1: The aim of this prospective pilot study is to determine the effect of heliox
delivered via a proprietary calibrated heated and humidified high flow nasal cannula (HFNC)
system (Vapotherm Precision Flow Heliox) in children ages 0-24 months with severe
bronchiolitis.

Hypothesis #1: Clinical and physiologic markers of respiratory distress will be improved in
patients receiving heliox via HFNC compared to standard therapy following separation from
mechanical ventilation.

Inclusion Criteria:

- Children 0-24 months

- Admission to the Pediatric Intensive Care Unit

- Diagnosis of bronchiolitis, with respiratory syncytial virus infection confirmed by
laboratory testing

- Mechanical ventilation

Exclusion Criteria:

- Inclusion in another clinical trial

- Significant cardiac disease

- Anatomically abnormal airway

- Neurologic disease

- Immunodeficiency

- History of chronic lung disease

- Craniofacial anomaly

- Chromosomal anomalies

- Known or suspected dysphagia