title: Neurally triggered breaths reduce trigger delay and improve ventilator response times in ventilated infants with bronchiolitis.
abstract: OBJECTIVE
  Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation designed to improve patient-ventilator interaction by interpreting a neural signal from the diaphragm to trigger a supported breath. We hypothesized that neurally triggered breaths would reduce trigger delay, ventilator response times, and work of breathing in pediatric patients with bronchiolitis.
  
  
  METHODS
  Subjects with a clinical diagnosis of bronchiolitis were studied in volume support (pneumatic trigger) and NAVA (pneumatic and neural trigger) in a crossover design. Airway flow and pressure waveforms were obtained with a pneumotachograph and computerized digital recorder and were recorded for 120 s for each experiment.
  
  
  RESULTS
  Neurally triggered breaths had less trigger delay (ms) (40 ± 27 vs. 98 ± 34; p < 0.001) and reduced ventilator response times (ms) (15 ± 7 vs. 36 ± 25; p < 0.001) compared with pneumatically triggered breaths. Neurally triggered breaths had reduced pressure-time product (PTP) area A (cmH(2)O * s), the area of the pressure curve from initiation of breath to start of ventilator pressurization (0.013 ± 0.010; p < 0.001), and reduced PTP area B (cmH(2)O * s), the area of the pressure curve from start of ventilator pressurization to return of baseline pressure (0.008 ± 0.006 vs. 0.023 ± 0.009; p = 0.003). Reduced PTP may indicate decreased work of breathing.
  
  
  CONCLUSIONS
  Neurally triggered breaths reduce trigger delay, improve ventilator response times, and may decrease work of breathing in children with bronchiolitis. Further analysis is required to determine if neurally triggered breaths will improve patient-ventilator synchrony.
authors.affiliation: Division of Pediatric Critical Care Medicine, Department of Anesthesiology, University of North Carolina at Chapel Hill, 214 MacNider, CB 7221, Chapel Hill, NC 27599-7221, USA. kclement@aims.unc.edu
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Clement
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Thurman
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Holt
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Heulitt
mesh_terms: D001131:Arkansas; D001988:Bronchiolitis / Q000628:therapy*; D002675:Child, Preschool; D018592:Cross-Over Studies; D003964:Diaphragm / Q000294:innervation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D012119:Respiration; D012121:Respiration, Artificial / Q000295:instrumentation* / Q000379:methods*; D013997:Time Factors; D014939:Work of Breathing