PT  - JOURNAL ARTICLE
AU  - Walter Verbrugghe
AU  - Philippe G Jorens
TI  - Neurally Adjusted Ventilatory Assist: A Ventilation Tool or a Ventilation Toy?
AID  - 10.4187/respcare.00775
DP  - 2011 Mar 01
TA  - Respiratory Care
PG  - 327--335
VI  - 56
IP  - 3
4099  - http://rc.rcjournal.com/content/56/3/327.short
4100  - http://rc.rcjournal.com/content/56/3/327.full
AB  - Mechanical ventilation has, since its introduction into clinical practice, undergone a major evolution from controlled ventilation to various modes of assisted ventilation. Neurally adjusted ventilatory assist (NAVA) is the newest development. The implementation of NAVA requires the introduction of a catheter to measure the electrical activity of the diaphragm (EAdi). NAVA relies, opposite to conventional assisted ventilation modes, on the EAdi to trigger the ventilator breath and to adjust the ventilatory assist to the neural drive. The amplitude of the ventilator assist is determined by the instantaneous EAdi and the NAVA level set by the clinician. The NAVA level amplifies the EAdi signal and determines instantaneous ventilator assist on a breath-to-breath basis. Experimental and clinical data suggest superior patient-ventilator synchrony with NAVA. Patient-ventilator asynchrony is present in 25% of mechanically ventilated patients in the intensive care unit and may contribute to patient discomfort, sleep fragmentation, higher use of sedation, development of delirium, ventilator-induced lung injury, prolonged mechanical ventilation, and ultimately mortality. With NAVA, the reliance on the EAdi signal, together with an intact ventilatory drive and intact breathing reflexes, allows integration of the ventilator in the neuro-ventilatory coupling on a higher level than conventional ventilation modes. The simple monitoring of the EAdi signal alone may provide the clinician with important information to guide ventilator management, especially during the weaning process. Although, until now, little evidence proves the superiority of NAVA on clinically relevant end points, it seems evident that patient populations (eg, COPD and small children) with major patient-ventilator asynchrony may benefit from this new ventilatory tool.