Abstract
Expiratory flow limitation (EFL) can occur in mechanically ventilated patients with chronic obstructive pulmonary disease and other disorders. It leads to dynamic hyperinflation with ensuing deleterious consequences. Detecting EFL is thus clinically relevant. Easily applicable methods however lack this detection being routinely made in intensive care. Using a simple mathematical model, we propose a new method to detect EFL that does not require any intervention or modification of the ongoing therapeutic. The model consists in a monoalveolar representation of the respiratory system, including a collapsible airway that is submitted to periodic changes in pressure at the airway opening: EFL provokes a sharp expiratory increase in the resistance Rc of the collapsible airway. The model parameters were identified via the Levenberg-Marquardt method by fitting simulated data on the airway pressure and the flow signals recorded in 10 mechanically ventilated patients. A sensitivity study demonstrated that only 8/11 parameters needed to be identified, the remaining three being given reasonable physiological values. Flow-volume curves built at different levels of positive expiratory pressure, PEEP, during “PEEP trials” (stepwise increases in positive end-expiratory pressure to optimize ventilator settings) have shown evidence of EFL in three cases. This was concordant with parameter identification (high Rc during expiration for EFL patients). We conclude from these preliminary results that our model is a potential tool for the non-invasive detection of EFL in mechanically ventilated patients.
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REFERENCES
Avanzolini, G.,P.Barbini, F.Bernardi, G.Cevenini and G.Gnudi (2001).Role of the mechanical properties of tracheobronchial airways in determining the respiratory resistance time course.Annals of Biomedical Engineering 29: 575–586.
Barbini, P.,G. Cevenini, F. Bernardi, M.R. Massai, G. Gnudi and G. Avanzolini (2001).Effect of compliant intermediate airways on total respiratory resistance and elastance in mechanical ventilation.Medical Engineering and Physics 23:185–94.
Barbini, P.,G. Cevenini and G. Avanzolini (2003).Nonlinear mechanisms determining expiratory flow limitation in mechanical ventilation:a model-based interpretation.Annals of Biomedical Engineering 31: 908–916.
Bland, J.and D. Altman (1986).Statistical methods for assessing agreement between two methods of clinical measurement.Lancet 1: 307–310.
Golden, J.F.,J.W. Clark and P.M. Stevens (1973).Mathematical Modelling of Pulmonary Airway Dynamics.IEEE Transactions on Biomedical Engineering 20: 397–404.
Heyer, L.,P. Baconnier, A. Eberhard, L. Biot, J-P Viale, J.P. Perdrix and P.Y. Carry (2002). Noninvasive detection of respiratory muscles activity during assisted ventilation.Comptes Rendus Biologies 325:1–9.
Khirani, S.,L. Biot, A. Eberhard and P. Baconnier (2001).Positive End Expiratory Pressure and Expiratory Flow Limitation:A Model Study.Acta Biotheoretica 49: 277–290.
Liu, C.H.,S.C. Niranjan, J.W. Clark, K.Y. San, J.B. Zwischenberger and A. Bidani (1998). Airway mechanics,gas exchange,and blood flow in a nonlinear model of the normal human lung.Journal of Applied Physiology 84:1447–1469.
Lourens, M.S.,B.V. Berg, H.C. Hoogsteden and J.M. Bogaard (2001).Detection of flow limitation in mechanically ventilated patients.Intensive Care Medicine 27:1312–20.
Mead, J.,J.M. Turner, P.T. Macklem and J.B. Little (1967).Significance of the relationship between lung recoil and maximum expiratory flow.Journal of Applied Physiology 22: 95–108.
Passing, H.and W. Bablok (1983).A new biometrical procedure for testing the equality of measurements from two different analytical methods.Application of linear regression procedures for method comparison studies in clinical chemistry,part i.Journal of Clinical Chemistry and Clinical Biochemistry 21: 709–720.
Valta, P.,C. Corbeil, A. Lavoie, R. Campodonico, N. Koulouris, M. Chasse, J. Braidy and J. Milic-Emili (1994).Detection of expiratory flow limitation during mechanical ventilation. American Journal of Respiratory and Critical Care Medicine 150:1311–1317.
Vassiliou, M.,R. Peslin, C. Saunier and C. Duvivier (1996).Expiratory flow limitation during mechanical ventilation detected by the forced oscillation method.European Respiratory Journal 9:779–86.
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Khirani, S., Biot, L., Lavagne, P. et al. Identification of a Non-Linear Model as a New Method to Detect Expiratory Airflow Limitation in Mechanically Ventilated Patients. Acta Biotheor 52, 241–254 (2004). https://doi.org/10.1023/B:ACBI.0000046596.43503.36
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DOI: https://doi.org/10.1023/B:ACBI.0000046596.43503.36