Selection of respiratory mode for weaning from ventilator

What mode is the best for weaning

Abstract

SIMV (synchronized intermittent mandatory ventilation) have been widely used during weaning process from mechanical ventilatory support. SIMV however, is not an optimal mode for weaning, because a patient sometimes complains of respiratory discomfort such as feeling of airway obstruction and dyspnea.
Aims of this study were performed to evaluate SIMV, CPAP and PSV (pressure support ventilation) which was provided with newly developed ventilators. From the results of comparison of work of breathing and oxygen consumption between demand valve type and continuous flow type, the first study indicated that patient's respiratory discomfort on IMV mode was attributable to airway resistance of respiratory circuit including valve system, when demand valve type's ventilator was used. On the second study, by using graphical analysis of presssure volume curve we observed the mechanical improvement about IMV/CPAP mode of recent advanced ventilators. As one of features of PSV which is recently designed, this mode can provide patient's demand inspiratory time, even though inspiratory airway pressure is reached to a clinician-selected level of assisted ventilation. On the clinical application of PSV to a patient during weaning process, patient comfort, reduced respiratory rate and decreased CO₂ production (VCO₂) were observed.
We may conclude that the PSV is thus the preferable pressure assist mode for intubated patients. The clinical significance of these properties during the weaning process remains to be determined and needs further investigation.