C. SCHRANZ ET AL.
Copyright © 2013 SciRes. ENG
Figure 4. Statistical analysis of identified model parameters in terms of plateau pressure (pPlat). Top line: FOM parameters,
Bottom lines: IHM parameters.
Thus, these model-based results may indicate the IHM
as an alternative approach to obtain measures of dynamic
changes of inhomogeneous lung aeration. Still, the inter-
pretation of model parameters, in particular, the validity
of the identified compartments are only valid if the mod-
el assumption is correct.
However, the same model prediction quality could be
obtained by the viscoelastic model (VEM), which de-
scribes the observed by the same equation but different
coefficients [5,14]. In this case, measured data of flow
rate and airway pressure lead to the problem of undistin-
guishable models. It is unclear whether the observed dy-
namics can be assigned to viscoelastic or inhomogeneity
characteristics. Thus, further investigations combined
with imaging methods are necessary to analyze both dy-
namics separately to further validate the model assump-
tions of the IHM.
Once the IHM is fully validated, it might offer a new
possibility to easily assess ventilation inhomogeneities to
evaluate and guide personalized lung protective ventila-
tor strategies on intensive care units.
5. Acknowledgements
The authors thank the McREM Study Group and Dräger
Medical for providing the clinical data for the evaluation.
This research was supported by the German Federal
Ministry of Education and Research (WiM-Vent, Grants
01IB10002D, PulMODS Grant 01DR12095) and by EU
FP7 PIRSES--GA-2012-318943 eTime.
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