Neurally adjusted ventilatory assist vs pressure support ventilation for noninvasive ventilation during acute respiratory failure: a crossover physiologic study.
BACKGROUND
Patient-ventilator asynchrony is common during noninvasive ventilation (NIV) with pressure support ventilation (PSV). We examined the effect of neurally adjusted ventilatory assist (NAVA) delivered through a facemask on synchronization in patients with acute respiratory failure (ARF).


METHODS
This was a prospective, physiologic, crossover study of 13 patients with ARF (median Pa(O(2))/F(IO(2)), 196 [interquartile range (IQR), 142-225]) given two 30-min trials of NIV with PSV and NAVA in random order. Diaphragm electrical activity (EAdi), neural inspiratory time (T(In)), trigger delay (Td), asynchrony index (AI), arterial blood gas levels, and patient discomfort were recorded.


RESULTS
There were significantly fewer asynchrony events during NAVA than during PSV (10 [IQR, 5-14] events vs 17 [IQR, 8-24] events, P = .017), and the occurrence of severe asynchrony (AI > 10%) was also less under NAVA (P = .027). Ineffective efforts and delayed cycling were significantly less with NAVA (P < .05 for both). NAVA was also associated with reduced Td (0 [IQR, 0-30] milliseconds vs 90 [IQR, 30-130] milliseconds, P < .001) and inspiratory time in excess (10 [IQR, 0-28] milliseconds vs 125 [IQR, 20-312] milliseconds, P < .001), but T(In) was similar under PSV and NAVA. The EAdi signal to its maximal value was higher during NAVA than during PSV ( P = .017). There were no significant differences in arterial blood gases or patient discomfort under PSV and NAVA.


CONCLUSIONS
In view of specific experimental conditions, our comparison of PSV and NAVA indicated that NAVA significantly reduced severe patient-ventilator asynchrony and resulted in similar improvements in gas exchange during NIV for ARF.


BACKGROUND
ClinicalTrials.gov; No.: NCT01426178; URL: www.clinicaltrials.gov.
Department of Anesthesiology and Critical Care, Estaing Hospital, University Hospital of Clermont-Ferrand, Clermont-Ferrand.
Pierre-Marie
PM
Bertrand
Department of Anesthesiology and Critical Care, Estaing Hospital, University Hospital of Clermont-Ferrand, Clermont-Ferrand. Electronic address: efutier@chu-clermontferrand.fr.
Emmanuel
E
Futier
Department of Anesthesiology and Critical Care (SAR B), Saint Eloi Hospital, University Hospital of Montpellier, Montpellier, France.
Yannael
Y
Coisel
Institut National de la Santé et de la Recherche Médicale (INSERM), Unit U1046, University of Montpellier, Montpellier, France.
Stefan
S
Matecki
Department of Anesthesiology and Critical Care (SAR B), Saint Eloi Hospital, University Hospital of Montpellier, Montpellier, France; Institut National de la Santé et de la Recherche Médicale (INSERM), Unit U1046, University of Montpellier, Montpellier, France.
Samir
S
Jaber
Department of Anesthesiology and Critical Care, Estaing Hospital, University Hospital of Clermont-Ferrand, Clermont-Ferrand.
Jean-Michel
JM
Constantin
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D059725:Interactive Ventilatory Support / Q000379:methods*; D008297:Male; D008875:Middle Aged; D063087:Noninvasive Ventilation / Q000379:methods*; D011175:Positive-Pressure Respiration / Q000379:methods*; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000628:therapy*