Additional Expiratory Resistance Elevates Airway Pressure and Lung Volume during High-Flow Tracheal Oxygen via Tracheostomy

Sci Rep. 2019 Oct 10;9(1):14542. doi: 10.1038/s41598-019-51158-0.

Abstract

The standard high-flow tracheal (HFT) interface was modified by adding a 5-cm H2O/L/s resistor to the expiratory port. First, in a test lung simulating spontaneous breathing, we found that the modified HFT caused an elevation in airway pressure as a power function of flow. Then, three tracheal oxygen treatments (T-piece oxygen at 10 L/min, HFT and modified HFT at 40 L/min) were delivered in a random crossover fashion to six tracheostomized pigs before and after the induction of lung injury. The modified HFT induced a significantly higher airway pressure compared with that in either T-piece or HFT (p < 0.001). Expiratory resistance significantly increased during modified HFT (p < 0.05) to a mean value of 4.9 to 6.7 cm H2O/L/s. The modified HFT induced significant augmentation in end-expiratory lung volume (p < 0.05) and improved oxygenation for lung injury model (p = 0.038) compared with the HFT and T-piece. There was no significant difference in esophageal pressure swings, transpulmonary driving pressure or pressure time product among the three treatments (p > 0.05). In conclusion, the modified HFT with additional expiratory resistance generated a clinically relevant elevation in airway pressure and lung volume. Although expiratory resistance increased, inspiratory effort, lung stress and work of breathing remained within an acceptable range.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Airway Resistance
  • Algorithms
  • Animals
  • Equipment Design
  • Exhalation
  • Female
  • Hemodynamics
  • Lung / physiology*
  • Oxygen / administration & dosage*
  • Positive-Pressure Respiration
  • Pulmonary Gas Exchange
  • Respiration
  • Respiratory Mechanics*
  • Swine
  • Tidal Volume
  • Tracheostomy / instrumentation*
  • Tracheostomy / methods*

Substances

  • Oxygen