Intraaortic balloon pumping and ventilatory support

Intraaortic balloon pump (IABP) is one of the mechanical methods to assist circulation to increase coronary blood flow and myocardial oxygen supply that are strictly related to ventricular energetics. This process can be affected by the application of mechanical ventilation. The aim of our computer simulation is to predict the influence of IABP on major energetic cardiovascular variables: external work (EW), pressure volume area (PVA), potential energy (PE) and cardiac mechanical efficiency (CME) in the presence of ventilatory support. Method: Pathological conditions of the heart were modelled by decreased left ventricle elastance (Ev=0.77 mmHgocm-3) and increased left ventricle rest volume (Vo=10 cm3). Systemic arterial resistance (Ras) was also changed during simulation (0.45 - 0.97 -1.52 mmHgocm-3osec). The influence of mechanical ventilation was introduced by positive mean thoracic pressures (Pt=0-5 mmHg). CARDIOSIM(C), the computer simulator of human cardiovascular system, was used to predict changes of energetic ventricular variables during ventilatory support and simultaneous IABP. Results and Conclusion: Positive thoracic pressure has a significant influence on the energetic cardiovascular variables. This fact should be taken into account during the simultaneous use of IABP and mechanical ventilation. Changes of Ras have a considerable effect on EW, PVA and PE of left ventricle when IABP is used or not. On the other hand energetic parameters of the right ventricle are not especially effected by changes of Ras.