The role of spontaneous breathing during mechanical ventilation.

The tremendous progress in microprocessor-driven ventilator technology over the last years has facilitated the introduction of a broad variety of different ventilatory modes into the clinical practice of mechanical ventilation. Many of these newer modalities are designed for partial ventilatory support, which might reflect the complexity of the issue of patient ventilator interactions when spontaneous breathing activity is present compared to controlled mechanical ventilation. There are reasons to believe that allowing some degree of spontaneous breathing activity during mechanical ventilation is useful not only to gradually withdraw ventilatory assistance in the process of weaning but also to avoid some of the adverse effects of mechanical ventilation in the early phase of acute respiratory failure when classically controlled modes of ventilation are used. It is the aim of this article to review the effects of preserved spontaneous breathing activity during mechanical ventilation with different ventilatory modalities in acute respiratory failure patients.