Measurement of the pulmonary input impedance for development of a sophisticated pulmonary vascular resistance model

The authors have been developing a pulmonary mechanical circulatory system in order to establish design parameters of artificial cardiovascular assist devices. In the quantitative examination of heart valves in pulmonary mock circulation, interactive changes in pressure and flow are regulated by pulmonary impedance characteristics. We focused on the native characteristics changes in impedance in the pulmonary circulation. To obtain the effect of respiratory control on pulmonary resistance, we measured pulmonary arterial pressure and flow in adult goat under the different respiratory settings with open- and closed-chest condition. We calculated pulmonary input impedance in two respiratory conditions under the anesthetized open-chest positive pressure ventilation (PPV) and the awake spontaneous respiration (SR). Longitudinal impedance in SR showed lower than in PPV. Characteristic impedance in SR was bigger than in PPV. Therefore, we concluded that the pulmonary impedance should be considered for more sophisticated simulation of pulmonary circulatory support devices.