Distal projection of insufflated gas during tracheal gas insufflation

Christopher S. Carter, John R. Hotchkiss, Alexander B. Adams, Mary K. Stone, John J. Marini

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Tracheal gas insufflation (TGI) flushes expired gas from the ventilator circuitry and central airways, augmenting CO2 clearance. Whereas a significant portion of this washout effect may occur distal to the injection orifice, the penetration and mixing behavior of TGI gas has not been studied experimentally. We examined the behavior of 100% oxygen TGI injected at set flow rates of 1-20 l/min into a simulated trachea consisting of a smooth-walled, 14-mm-diameter tube. Models incorporating a separate coaxial TGI injector, a rough-walled trachea, and a bifurcated trachea were also studied. One-hundred percent nitrogen, representing expiratory flow, passed in the direction opposite to TGI at set flow rates of 1-25 l/min. Oxygen concentration within the "trachea" was mapped as a function of axial and radial position. Three consistent findings were observed: 1) mixing of expiratory and TGI gases occurred close to the TGI orifice; 2) the oxygenated domain extended several centimeters beyond the endotracheal tube, even at high-expiratory flows, but had a defined distal limit; and 3) more distally from the site of gas injection, the TGI gas tended to propagate along the tracheal wall, rather than as a central projection. We conclude that forward-directed TGI penetrates a substantial distance into the central airways, extending the compartment susceptible to CO2 washout.

Original languageEnglish (US)
Pages (from-to)1843-1850
Number of pages8
JournalJournal of applied physiology
Issue number5
StatePublished - 2002


  • Artificial respiration
  • Pulmonary gas exchange
  • Respiratory dead space
  • Respiratory failure


Dive into the research topics of 'Distal projection of insufflated gas during tracheal gas insufflation'. Together they form a unique fingerprint.

Cite this