Neurally adjusted NIV improves patient-ventilator interaction in COPD

Background: Non-invasive ventilation (NIV) still frequently fails in managing acute respiratory failure. Amongst the reasons for NIV failure is poor patient-ventilator interaction (PVI). Neurally adjusted ventilatory assist (NAVA) is a ventilator mode that uses electrical activity of the diaphragm (Edi) to control ventilation. There are no studies of PVI during NIV-NAVA in strictly COPD patients, while these patients are most likely to exhibit poor PVI. Therefore, our aim was to compare PVI between NAVA and conventional modes in COPD patients. Methods: Twelve COPD patients were ventilated for 30 minutes with: PSV with the BiPAP Vision (dedicated NIV ventilator); PSV with the Servo-I (ICU ventilator); and NAVA. PVI was evaluated by comparing airway pressure and Edi with computer algorithms. Results: Figure 1 depicts individual trigger delays and cycle-off errors for each mode. Figure 2 plots the distribution of synchrony, dyssynchrony and asynchronies for each mode. Conclusion: This study shows that NIV-NAVA synchronizes assist to inspiratory effort in COPD patients, whereas PSV (with dedicated and ICU ventilator) does not ensure acceptable patient-ventilator interaction.