Does Neurally Adjusted Ventilatory Assist Compared to Pressure Support Ventilation Decrease Patient Ventilator Asynchrony?

Abstract

BACKGROUND: Patient-mechanical ventilator (MV) asynchrony despite optimal adjustment of MV parameters is a common problem that is partly associated with difficult weaning of MV. Neurally adjusted ventilatory assist (NAVA) is a mode of proportional ventilation that count on diaphragmatic activity (measured by special esophageal probe and expressed as diaphragm electrical [Edi]) to provide proportional support to patient effort which differs from one breath to another according to Edi signal. AIM: The purpose of this trial is to determine the impact of NAVA compared to pressure support ventilation (PSV) mode in decreasing patient-MV asynchrony and hemodynamic effect in patients on MV with expected difficult weaning. MATERIALS AND METHODS: This prospective interventional trial was conducted on 30 critically ill on MV with expected difficult weaning. First, patients were put on PSV mode for 24 h. Then, patients were put on NAVA mode (for weaning) for the next 24 h. The incidence of different types of asynchrony in both modes was investigated. RESULTS: NAVA mode significantly reduced the asynchrony index when compared to PSV (1.1 ± 0.39% vs. 2.8 ± 1.1, respectively, p < 0.001), P/F ratio was significantly higher during NAVA (250 in NAVA vs. 210 in PSV, p < 0.001), heart rate, and mean arterial blood pressure were significantly reduced during NAVA (p < 0.001 and 0.015, respectively). CONCLUSIONS: Compared to PSV, NAVA-reduced patient-MV asynchrony significantly and increased the P/F ratio significantly with better hemodynamics.