Heartrate Variability During Conventional and Variable Pressure Support Mechanical Ventilation

Rationale Studies show that about a third of all postoperative complications are due to cardiovascular reasons. Furthermore it was shown that more than 50% of postoperative deaths are associated with severe cardiovascular incidents. After surgical interventions seriously ill patients are transferred to intensive care units and mechanically ventilated. However there is not much evidence about the impact of mechanical ventilation on the cardiovascular system and cardiovascular complications. Artificial mechanical ventilation greatly differs from physiological breathing. In contrast to physiological negative pressure ventilation of th lung, mechanical positive pressure ventilation can cause ventilator induced lung injuries. Furthermore a significant deterioration of lung-heart-interaction during mechanical ventilation is known. Relevance Mechanical ventilation leads to a decreased heartrate-variability, which has to be understood as increased stress on the cardiovascular system. Recently, a new ventilation mode called \"variable pressure support ventilation\" (VPSV) also known as \"noisy pressure support ventilation\". This new ventilation mode is similar to the ventilator mode \"spontaneous-continuous positive airway pressure/pressure support\" (SPN-CPAP), which is often used in a intensive care unit routine. Though VPSV differs through varying applicated pressure support and therefore tidal volumes. Therefore the new ventilation mode rather imitates physiological situation, since tidal volumes vary in physiological breathing, which has positive impact on heart-lung-interaction.