High flow nasal cannula in the pediatric intensive care unit

ABSTRACT

Introduction

The use of high flow nasal cannula (HFNC) has become widely used in pediatric intensive care units (PICUs) throughout the world. The rapid adoption has outpaced the number of studies evaluating the safety and efficacy in a variety of pediatric diseases/conditions.

Areas covered

This scoping review begins with the definition and mechanisms of action of HFNC and then follows with a review of the literature focused on studies performed on critically ill children cared for in the PICU. The PubMed database was searched with a pediatric filter from the time period 2000 to 2021.

Expert opinion

The rapid adoption of HFNC in PICUs has largely been driven by changes in institutional practices and small observational studies. There is a lack of adequately powered studies evaluating patient-centered outcomes, such as intubation rates, mortality, PICU, and hospital length of stay. Given the wide variability in flow rates and clinical indications, more research is needed to better define effective flow rates for different disease states as well as markers of treatment success and failure. One particular entity that is poorly studied is the use of HFNC in those at risk for developing pediatric acute respiratory distress syndrome (PARDS).

KEYWORDS:

• High flow nasal cannula
• pediatric intensive care unit
• acute lung injury
• pediatric acute respiratory distress syndrome
• bronchiolitis
• hypoxia
• hypercapnia
• infant
• pediatric

Article highlights

• Several mechanisms are postulated to demonstrate efficacy of HFNC, including improving mucociliary clearance and reducing bronchoreactivity with heated and humidified gas, increasing effective FiO₂ by providing oxygen-rich gas, washing out nasopharyngeal deadspace, improving work of breathing by improving diaphragm dynamics, and reducing airway resistance by applying positive pharyngeal pressure.

• The application of HFNC in the pediatric intensive care unit, initially studied as an alternative for noninvasive ventilation, has largely been driven by small observational studies that have been generally consistent in showing a therapeutic benefit with respect to vital signs and clinical measures of the patient’s work of breathing, although definitive outcome data are lacking.

• The most common and well-studied indication for HFNC in the PICU is acute bronchiolitis.

• For asthma, aerosol delivery via HFNC is significantly reduced with higher flow rates and smaller cannula sizes.

• More research is needed in patients at risk for PARDS, including optimal flow rates, risk factors for progression to PARDS, and factors related to prevention of progression to PARDS.

• There is wide variability in practice with respect to flow settings and disease indications as well as a lack of studies evaluating indications for initiating, escalating, and weaning of HFNC therapy.

• When compared to conventional therapies, HFNC appears safe in a variety of conditions including asthma, bronchiolitis, pneumonia, and post-extubation respiratory distress.

• Given the broad acceptance of HFNC and perceived lack of equipoise, future studies utilizing the tools of Quality Improvement may be helpful to design initiation and weaning protocols and appropriate flow rates for a range of disease indications.

Declaration of interests

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.