Influence of inertance on respiratory mechanics measurements in mechanically ventilated puppies

Lanteri, C.J., Petak, F., Gurrin, L. and Sly, P.D. (1999) Influence of inertance on respiratory mechanics measurements in mechanically ventilated puppies. Pediatric Pulmonology, 28 2: 130-138. doi:10.1002/(SICI)1099-0496(199908)28:2<130::AID-PPUL9>3.0.CO;2-X

Author Lanteri, C.J.
Petak, F.
Gurrin, L.
Sly, P.D.
Title Influence of inertance on respiratory mechanics measurements in mechanically ventilated puppies
Journal name Pediatric Pulmonology   Check publisher's open access policy
ISSN 8755-6863
Publication date 1999-08
Sub-type Article (original research)
DOI 10.1002/(SICI)1099-0496(199908)28:2<130::AID-PPUL9>3.0.CO;2-X
Volume 28
Issue 2
Start page 130
End page 138
Total pages 9
Place of publication Hoboken, NJ, United States
Publisher John Wiley & Sons
Language eng
Abstract The complete equation of motion for a single compartment model (SCM) includes an inertance term to describe pressure changes in phase with acceleration, as well as terms for resistance and elastance. Inertance has traditionally been excluded from the model when measuring respiratory mechanics at conventional ventilatory frequencies in mature respiratory systems. However, this omission has been questioned recently for measurements of respiratory mechanics in intubated infants where higher ventilation frequencies and smaller tracheal tubes are the norm. We investigated 1) the significance of inertance in an immature respiratory system during mechanical ventilation, and 2) the effect of omitting it from the model on estimates of respiratory mechanics. Six anesthetised, paralysed and mechanically ventilated puppies (2.6-3.9 kg) were studied. A SCM, including an inertance term was fitted to measurements of flow and airway opening (P(AO)) or transpulmonary (P(TP)) pressure using multiple linear regression to estimate respiratory system and lung resistance (R(RS), R(L)), elastance (E(RS), E(L)) and inertance (I(RS), I(L)) respectively, at various ventilation frequencies (0.2-2 Hz). Data obtained at each ventilation frequency were also fitted with a similar model without the inertance term. Inertance contributed significantly to the model at frequencies greater than approximately 0.3-0.5 Hz (20-30 breaths per minute), with I(RS) dominated by the lung. The importance of including the inertance term in the model increased as ventilation frequency increased. Exclusion of inertance from the model led to underestimation of E(RS) and E(L), but no errors in estimates of R(RS) or R(L). The errors increased with ventilation frequency to ~10-20% for E(RS) and ~10-40% for E(L) at 2 Hz. While inertance contributed significantly to the SCM at ventilation frequencies typically required to maintain normal gas exchange in puppies, the errors from excluding this term were small: <3% for E(RS) and <9% for E(L).
Keyword Modeling
Frequency dependence
Pulmonary function
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Medicine Publications
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Citation counts: TR Web of Science Citation Count  Cited 13 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 17 Nov 2010, 11:36:53 EST