Physiologic effect of high-flow nasal cannula in infants with bronchiolitis.

OBJECTIVE: To assess the effect of delivering high-flow nasal cannula flow on end-expiratory lung volume, continuous distending pressure, and regional ventilation distribution in infants less than 12 months old with bronchiolitis.

DESIGN: Prospective observational clinical study.

SETTING: Nineteen bed medical and surgical PICU.

PATIENTS: Thirteen infants with bronchiolitis on high-flow nasal therapy.

INTERVENTIONS: The study infants were measured on a flow rate applied at 2 and 8 L/min through the high-flow nasal cannula system.

MEASUREMENTS AND RESULTS: Ventilation distribution was measured with regional electrical impedance amplitudes and end-expiratory lung volume using electrical impedance tomography. Changes in continuous distending pressure were measured from the esophagus via the nasogastric tube. Physiological variables were also recorded. High-flow nasal cannula delivered at 8 L/min resulted in significant increases in global and anterior end-expiratory lung volume (p < 0.01) and improvements in the physiological variables of respiratory rate, SpO2, and FIO2 when compared with flows of 2 L/min.

CONCLUSION: In infants with bronchiolitis, high-flow nasal cannula oxygen/air delivered at 8 L/min resulted in increases in end-expiratory lung volume and improved respiratory rate, FIO2, and SpO2.