Journal of Applied Physiology, Vol 52, Issue 4 955-963, Copyright © 1982 by American Physiological Society
Parameter estimation of transpulmonary mechanics by a nonlinear inertive model
Z. Hantos, B. Daroczy, J. Klebniczki, K. Dombos and S. Nagy
Transpulmonary mechanics of anesthetized intubated dogs were studied during
control breathing and hemorrhage-induced hyperventilation by
least-mean-squares parameter estimation using several model versions. The
classical elastance-resistance model was modified to include nonlinear
elastic and viscous pressure terms with and without a linear inertive
pressure component. Inclusion of the nonlinear terms decreased the
root-mean-square error of fitting (q) of the classical model on the average
to 67% in the control period and to 58% during hyperventilation. An
additional decrease due to inertance was 4% (control) and 22%
(hyperventilation) and was associated with acceptable estimates of
inertance [0.056 +/- 0.02 (SD) and 0.063 +/- 0.008 cmH2O . l-1 . s2,
respectively]. When inertance alone was added to the classical model,
negligible improvement in q and unrealistic values of inertance were
obtained. Conventional measures (Edyn and midvolume resistance) were close
to the corresponding least-mean-squares estimates (E and R) of all model
versions, except that in hyperventilation neglecting the inertance caused
Edyn to markedly overestimate E of nonlinear inertive model.
