A Simple Dynamic Model of Respiratory Pump

Abstract

To study the interaction of forces that produce chest wall motion, we propose a model based on the lever system of Hillman and Finucane (J Appl Physiol 63(3):951-961, 1987) and introduce some dynamic properties of the respiratory system. The passive elements (rib cage and abdomen) are considered as elastic compartments linked to the open air via a resistive tube, an image of airways. The respiratory muscles (active) force is applied to both compartments. Parameters of the model are identified in using experimental data of airflow signal measured by pneumotachography and rib cage and abdomen signals measured by respiratory inductive plethysmography on eleven healthy volunteers in five conditions: at rest and with four level of added loads. A breath by breath analysis showed, whatever the individual and the condition are, that there are several breaths on which the airflow simulated by our model is well fitted to the airflow measured by pneumotachography as estimated by a determination coefficient R(2) > or = 0.70. This very simple model may well represent the behaviour of the chest wall and thus may be useful to interpret the relative motion of rib cage and abdomen during quiet breathing.

Mathematical Modeling of Respiratory System Mechanics in the Newborn Lamb

“…Previous studies have proposed simplified mechanical models of the respiratory system, including the rib cage and the abdominal compartments [4] and mathematical models of the central respiratory oscillator [10] [39] [40] to represent respiratory muscle activity. Such a description is very useful to study the effects of respiratory rate variations, but the oscillator parameters do not explicitly describe the respiratory signal morphology and thus, reproduction of real respiratory waveforms cannot be performed with this approach.…”