The influence of ventilatory support on coronary flow and oxygen consumption in different circulatory conditions.

The aim of this work is to predict the influence of mechanical ventilation on cardiac output, coronary flow and left ventricular myocardial oxygen consumption in different circulatory conditions. To study this interaction we used a computer simulator of human cardiovascular system in which lumped parameters models were used to reproduce the circulatory phenomena in terms of pressure and volume relationships. Variable elastance models reproduce the Starling's law of the heart, for each ventricle. In the study the left ventricular elastance assumed two different values. Systemic arterial resistance was changed during the simulation. The influenece of mechanical ventilation was introduced by positive mean thoracic pressure. Positive thoracic pressure, changes of peripheral resistance and different ventricular elastance values have a significant influence on cardiac output, coronary flow and myocardial oxygen consumption.