A Comparison of Adaptive Support Ventilation (ASV) and Conventional Volume-Controlled Ventilation on Respiratory Mechanics in Acute Lung Injury/ARDS

Abstract

Background ASV is a closed-loop ventilation system that guarantees a user-set minimum per-minute volume in intubated patients, whether paralyzed or with spontaneous breathing. Here, we tested the effects of ASV onrespiratory mechanics and compared them with volume-controlled ventilation (VCV). Methods Thirteen patients meeting the criteria for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) were enrolled. All patients were paralyzed to eliminate spontaneous breathing. We started with VCV (VCV1), then used ASV followed by VCV modes (VCV2), maintaining minute volume as much as that of VCV1. Results During ASV, compared with VCV1, the inspiratory and expiratory tidal volumes and expiratory resistance increased. Conversely, the total respiratory rate and maximum pressure decreased. No changes in the arterial blood gases, heart rate, or mean systemic pressure were noted during the trial. Conclusions In ALI/ARDS patients, although no differences were observed in the arterial blood gas analysis between the two modes, ASV provided better respiratory mechanics in terms of peak airway pressure and tidal volume than VCV.