The effect of high flow nasal cannula therapy on the work of breathing in infants with bronchiolitis

Pediatr Pulmonol. 2015 Jul;50(7):713-20. doi: 10.1002/ppul.23060. Epub 2014 May 21.


The main physiological impact of high flow nasal cannula (HFNC) therapy is presumed to be a decrease in work of breathing (WOB). To assess this, diaphragmatic electrical activity and esophageal pressure changes were measured off then on HFNC delivered at 2 L/kg/min, in 14 infants with bronchiolitis and 14 cardiac infants. Electrical activity of the diaphragm (Edi) was measured using an Edi catheter with calculations of signal peak (EdiMAX ) and amplitude (EdiAMPL ). Pressure-rate and pressure-time products (PRP, PTP) were calculated from analyses of esophageal pressure. Changes in end-expiratory lung volume were measured using respiratory inductance plethysmography (RIPEEL ). The EdiMAX and EdiAMPL were significantly higher in infants with bronchiolitis than in cardiac infants (P < 0.05). Within the bronchiolitis group, both were significantly reduced between HFNC states from 27.9 µV [20.4, 35.4] to 21.0 µV [14.8, 27.2] and from 25.1 µV [18.0, 32.2] to 19.2 µV [13.3, 25.1], respectively (mean, 95% CI, P < 0.05). A less prominent offload of the diaphragm was observed in cardiac infants (P < 0.05). WOB decreased in both groups with a significant reduction of PRP and PTP (P < 0.05). RIPEEL increased significantly in bronchiolitis only (P < 0.05). HFNC offloads the diaphragm and reduces the WOB in bronchiolitis. A similar effect was demonstrated in cardiac infants, a group without signs of airway-obstruction.

Keywords: breathing pattern; electrical activity of the diaphragm; end expiratory level; esophageal pressure; oxygen therapy; respiratory distress.

Publication types

  • Clinical Study
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bronchiolitis / physiopathology
  • Bronchiolitis / therapy*
  • Diaphragm / physiology
  • Esophagus / physiology
  • Heart Defects, Congenital / physiopathology
  • Humans
  • Infant
  • Oxygen Inhalation Therapy / methods*
  • Plethysmography
  • Pressure
  • Prospective Studies
  • Work of Breathing / physiology*