Pressure support versus assisted controlled noninvasive ventilation in neuromuscular disease

Introduction: Noninvasive ventilation (NIV) is being increasingly used in patients with chronic neuromuscular disorders, but the optimal ventilation mode remains unknown. We compared physiological short-term effects of assist/controlled ventilation (ACV) and two pressure-limited modes (pressure-support ventilation PSV] and assist pressure-controlled ventilation ACPV]) in patients with neuromuscular disease who needed NIV. Methods: Tidal volume was 10 to 12 mL/kg. The ACPV mode used the same respiratory cycle timing as the volume-limited mode. The level of inspiratory support was set to achieve the same tidal volume during the other ventilatory modes. Results: Thirteen patients with neuromuscular disease who met international criteria for NIV were included. The three ventilatory modes increased alveolar ventilation and decreased respiratory effort indices. However, no difference in breathing or respiratory effort was found among the three modes, with the exception that inspiratory peak flow and percentage of triggered cycles were higher during PSV than volume-limited ventilation. Interestingly, no relationship was observed between subjective patient preference and inspiratory effort indices or percentage of triggered cycles. Conclusion: In chronic, stable patients with neuromuscular disease, both noninvasive ACV, ACPV, and PSV had similar effects on alveolar ventilation and respiratory muscle unloading, despite some differences in the pattern of breathing and percentage of triggered cycles.