Heated high flow nasal cannula flow rates in critical pediatric asthma: an observational cohort study

Area of Science:

• Pediatric Critical Care Medicine
• Respiratory Therapy
• Pharmacology

Background:

• Heated high flow nasal cannula (HHFNC) use is increasing in pediatric critical asthma management.
• Concerns exist regarding the efficacy of HHFNC in delivering nebulized medications to the lower airway.
• Optimal HHFNC flow rates for continuous medication delivery remain under investigation.

Purpose of the Study:

• To evaluate the association between low versus high HHFNC flow rates and clinical outcomes in critically ill pediatric asthma patients receiving continuously inhaled short acting beta agonist (cSABA).
• To determine if HHFNC flow rate impacts the duration of cSABA treatment, respiratory support, and length of stay.

Main Methods:

• Retrospective cohort study of pediatric intensive care unit (PICU) patients with critical asthma receiving HHFNC for cSABA delivery.
• Patients were categorized into low flow (≤5 L/min) and high flow (>5 L/min) groups based on average HHFNC flow rate.
• Outcomes analyzed included duration of cSABA, noninvasive respiratory support (HHFNC, CPAP, BPAP), and PICU/hospital length of stay (LOS).

Main Results:

• 112 patients were included; high flow group received significantly higher median HHFNC flow rates (9.6 L/min vs. 4.0 L/min).
• The low flow group demonstrated significantly shorter total duration of cSABA (p=0.048).
• Low flow HHFNC was associated with shorter durations of noninvasive respiratory support (p=0.0234), PICU LOS (p<0.001), and hospital LOS (p=0.0063).

Conclusions:

• Lower HHFNC flow rates for cSABA delivery in pediatric critical asthma are associated with improved clinical outcomes.
• Shorter durations of cSABA, noninvasive respiratory support, and reduced hospital length of stay were observed with lower flow rates.
• These findings suggest that optimizing HHFNC flow settings may be beneficial for managing pediatric critical asthma.