title: Neurally adjusted ventilatory assist (NAVA) improves patient-ventilator interaction during non-invasive ventilation delivered by face mask.
abstract: OBJECTIVE
  To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation with an oronasal face mask.
  
  
  METHODS
  In this prospective interventional study we compared patient-ventilator synchrony between PS (with ventilator settings determined by the clinician) and NAVA (with the level set so as to obtain the same maximal airway pressure as in PS). Two 20-min recordings of airway pressure, flow and electrical activity of the diaphragm during PS and NAVA were acquired in a randomized order. Trigger delay (T(d)), the patient's neural inspiratory time (T(in)), ventilator pressurization duration (T(iv)), inspiratory time in excess (T(iex)), number of asynchrony events per minute and asynchrony index (AI) were determined.
  
  
  RESULTS
  The study included 13 patients, six with COPD, and two with mixed pulmonary disease. T(d) was reduced with NAVA: median 35 ms (IQR 31-53 ms) versus 181 ms (122-208 ms); p = 0.0002. NAVA reduced both premature and delayed cyclings in the majority of patients, but not the median T(iex) value. The total number of asynchrony events tended to be reduced with NAVA: 1.0 events/min (0.5-3.1 events/min) versus 4.4 events/min (0.9-12.1 events/min); p = 0.08. AI was lower with NAVA: 4.9 % (2.5-10.5 %) versus 15.8 % (5.5-49.6 %); p = 0.03. During NAVA, there were no ineffective efforts, or late or premature cyclings. PaO(2) and PaCO(2) were not different between ventilatory modes.
  
  
  CONCLUSIONS
  Compared to PS, NAVA improved patient ventilator synchrony during noninvasive ventilation by reducing T(d) and AI. Moreover, with NAVA, ineffective efforts, and late and premature cyclings were absent.
authors.affiliation: Intensive Care and Burn Unit, University Hospital of Lausanne (CHUV), Lausanne, Switzerland. lise.piquilloud@chuv.ch
authors.forename: Lise
authors.initials: L
authors.lastname: Piquilloud
authors.forename: Didier
authors.initials: D
authors.lastname: Tassaux
authors.forename: Emilie
authors.initials: E
authors.lastname: Bialais
authors.forename: Bernard
authors.initials: B
authors.lastname: Lambermont
authors.forename: Thierry
authors.initials: T
authors.lastname: Sottiaux
authors.forename: Jean
authors.initials: J
authors.lastname: Roeseler
authors.forename: Pierre-François
authors.initials: PF
authors.lastname: Laterre
authors.forename: Philippe
authors.initials: P
authors.lastname: Jolliet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Revelly
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D059725:Interactive Ventilatory Support / Q000379:methods*; D008297:Male; D008397:Masks; D008875:Middle Aged; D063087:Noninvasive Ventilation / Q000379:methods*; D011446:Prospective Studies; D012128:Respiratory Distress Syndrome / Q000628:therapy*; D012131:Respiratory Insufficiency / Q000628:therapy*