### Abstract

We present a theoretical model of gas transport through the dead space during high-frequency ventilation (HFV) with volumes less than dead space volume. The analysis is based on the axial distribution of transit times of gas moving through the dead space. The model predicts that for tidal volumes (V) much less than dead space (V_{d}), gas exchange will be proportional to the product of frequency (f) and V^{2}. If gas transport is analyzed in terms of Fick's law, then the effective diffusion coefficient (D_{eff}) can be shown to be equal to fV^{2} times a constant, whose value equals the square of the coefficient of dispersion of axial transit times through the dead space {Mathematical expression}. Experimental results in straight tubes fit the predictions of this model quite well. A {Mathematical expression} through the entire dead space of about 30% is more than sufficient to account for gas exchange during HFV in physical models or in intact animals. An axial dispersion of this magnitude can be measured directly from a typical Fowler dead space determination in healthy subjects.

Original language | English (US) |
---|---|

Pages (from-to) | 407-419 |

Number of pages | 13 |

Journal | Annals of Biomedical Engineering |

Volume | 12 |

Issue number | 4 |

DOIs | |

State | Published - Jul 1984 |

### Fingerprint

### Keywords

- Dead space
- Effective diffusivity
- Enhanced diffusion
- Gamma distribution

### ASJC Scopus subject areas

- Biomedical Engineering

### Cite this

*Annals of Biomedical Engineering*,

*12*(4), 407-419. https://doi.org/10.1007/BF02407783

**Gas transport during high-frequency ventilation : Theoretical model and experimental validation.** / Mitzner, Wayne A; Permutt, S.; Weinmann, G.

Research output: Contribution to journal › Article

*Annals of Biomedical Engineering*, vol. 12, no. 4, pp. 407-419. https://doi.org/10.1007/BF02407783

}

TY - JOUR

T1 - Gas transport during high-frequency ventilation

T2 - Theoretical model and experimental validation

AU - Mitzner, Wayne A

AU - Permutt, S.

AU - Weinmann, G.

PY - 1984/7

Y1 - 1984/7

N2 - We present a theoretical model of gas transport through the dead space during high-frequency ventilation (HFV) with volumes less than dead space volume. The analysis is based on the axial distribution of transit times of gas moving through the dead space. The model predicts that for tidal volumes (V) much less than dead space (Vd), gas exchange will be proportional to the product of frequency (f) and V2. If gas transport is analyzed in terms of Fick's law, then the effective diffusion coefficient (Deff) can be shown to be equal to fV2 times a constant, whose value equals the square of the coefficient of dispersion of axial transit times through the dead space {Mathematical expression}. Experimental results in straight tubes fit the predictions of this model quite well. A {Mathematical expression} through the entire dead space of about 30% is more than sufficient to account for gas exchange during HFV in physical models or in intact animals. An axial dispersion of this magnitude can be measured directly from a typical Fowler dead space determination in healthy subjects.

AB - We present a theoretical model of gas transport through the dead space during high-frequency ventilation (HFV) with volumes less than dead space volume. The analysis is based on the axial distribution of transit times of gas moving through the dead space. The model predicts that for tidal volumes (V) much less than dead space (Vd), gas exchange will be proportional to the product of frequency (f) and V2. If gas transport is analyzed in terms of Fick's law, then the effective diffusion coefficient (Deff) can be shown to be equal to fV2 times a constant, whose value equals the square of the coefficient of dispersion of axial transit times through the dead space {Mathematical expression}. Experimental results in straight tubes fit the predictions of this model quite well. A {Mathematical expression} through the entire dead space of about 30% is more than sufficient to account for gas exchange during HFV in physical models or in intact animals. An axial dispersion of this magnitude can be measured directly from a typical Fowler dead space determination in healthy subjects.

KW - Dead space

KW - Effective diffusivity

KW - Enhanced diffusion

KW - Gamma distribution

UR - http://www.scopus.com/inward/record.url?scp=0021734859&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021734859&partnerID=8YFLogxK

U2 - 10.1007/BF02407783

DO - 10.1007/BF02407783

M3 - Article

C2 - 6532274

AN - SCOPUS:0021734859

VL - 12

SP - 407

EP - 419

JO - Annals of Biomedical Engineering

JF - Annals of Biomedical Engineering

SN - 0090-6964

IS - 4

ER -