Abstract
The authors have been developing a pulmonary mechanical simulator in order to establish a design parameters of a novel artificial cardiovascular devices. In pulmonary circulation, interactive pressure-flow changes are regulated by pulmonary impedance characteristics. We focused on the native impedance characteristics variation in the pulmonary circulation. To examine 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/closed-chest condition. Pulmonary input impedance in two respiratory conditions under the anesthetized open-chest positive pressure ventilation (PPV) and the awake spontaneous respiration (SR) were calculated. Longitudinal impedance at 0 Hz in SR showed lower than in PPV, and at high harmonic area in SR was bigger than in PPV. In order to examine the hemodynamic response for newly designed artificial internal organs, pulmonary impedance variation caused by respiratory control should be considered. For sophisticated pulmonary resistance model, reproducing the negative pressure condition in the thoracic cavity, and pulmonic vascular resistance regulation might be required.
