Effects of Neurally Adjusted Ventilatory Assist (NAVA) Levels in Non-invasive Ventilated Patients: Titrating NAVA Levels with Electric Diaphragmatic Activity and Tidal Volume Matching

摘要

Background: Neurally adjusted ventilatory assist (NAVA) delivers pressure in proportionto diaphragm electrical activity (Eadi). However, each patient responds differently toNAVA levels. This study aims to examine the matching between tidal volume (Vt) andpatients’ inspiratory demand (Eadi), and to investigate patient-specific response tovarious NAVA levels in non-invasively ventilated patients.Methods: 12 patients were ventilated non-invasively with NAVA using three differentNAVA levels. NAVA100 was set according to the manufacturer’s recommendation tohave similar peak airway pressure as during pressure support. NAVA level was thenadjusted ±50% (NAVA50, NAVA150). Airway pressure, flow and Eadi were recorded for15 minutes at each NAVA level. The matching of Vt and integral of Eadi (ʃEadi) wereassessed at the different NAVA levels. A metric, Range90, was defined as the 5-95%range of Vt/ʃEadi ratio to assess matching for each NAVA level. Smaller Range90 valuesindicated better matching of supply to demand.