title: Influence of different interfaces on synchrony during pressure support ventilation in a pediatric setting: a bench study.
abstract: BACKGROUND
  In adults and children, patient-ventilator synchrony is strongly dependent on both the ventilator settings and interface used in applying positive pressure to the airway. The aim of this bench study was to determine whether different interfaces and ventilator settings may influence patient-ventilator interaction in pediatric models of normal and mixed obstructive and restrictive respiratory conditions.
  
  
  METHODS
  A test lung, connected to a pediatric mannequin using different interfaces (endotracheal tube [ETT], face mask, and helmet), was ventilated in pressure support ventilation mode testing 2 ventilator settings (pressurization time [Timepress]50%/cycling-off flow threshold [Trexp]25%, Timepress80%/Trexp60%), randomly applied. The test lung was set to simulate one pediatric patient with a healthy respiratory system and another with a mixed obstructive and restricted respiratory condition, at different breathing frequencies (f) (30, 40, and 50 breaths/min). We measured inspiratory trigger delay, pressurization time, expiratory trigger delay, and time of synchrony.
  
  
  RESULTS
  At each breathing frequency, the helmet showed the longest inspiratory trigger delay compared with the ETT and face mask. At f30, the ETT had a reduced Tpress. The helmet had the shortest Tpress in the simulated child with a mixed obstructive and restricted respiratory condition, at f40 during Timepress50%/Trexp25% and at f50 during Timepress80%/Trexp60%. In the simulated child with a normal respiratory condition, the ETT presented the shortest Tpress value at f50 during Timepress80%/Trexp60%. Concerning the expiratory trigger delay, the helmet showed the best interaction at f30, but the worst at f40 and at f50. The helmet showed the shortest time of synchrony during all ventilator settings.
  
  
  CONCLUSIONS
  The choice of the interface can influence patient-ventilator synchrony in a pediatric model breathing at increased f, thus making it more difficult to set the ventilator, particularly during noninvasive ventilation. The helmet demonstrated the worst interaction, suggesting that the face mask should be considered as the first choice for delivering noninvasive ventilation in a pediatric model.
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Conti
authors.affiliation: Post Anesthesia Care Unit, Pain Service, M Adelaide Hospital, Emergency and Intensive Care, Turin, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Gregoretti
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Spinazzola
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy olimpia.mp.festa@gmail.com.
authors.forename: Olimpia
authors.initials: O
authors.lastname: Festa
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Ferrone
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Flora
authors.initials: F
authors.lastname: Cipriani
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Rossi
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Piastra
authors.affiliation: Institute of Anesthesiology and Intensive Care and Pediatric ICU, Policlinico A Gemelli, Catholic University, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Costa
mesh_terms: D002648:Child; D006260:Head Protective Devices; D006801:Humans; D059725:Interactive Ventilatory Support / Q000295:instrumentation* / Q000379:methods; D007442:Intubation, Intratracheal; D008348:Manikins; D008397:Masks; D063087:Noninvasive Ventilation / Q000295:instrumentation* / Q000379:methods; D011175:Positive-Pressure Respiration / Q000295:instrumentation* / Q000379:methods; D012119:Respiration; D015656:Respiratory Mechanics / Q000502:physiology*; D012122:Ventilators, Mechanical
keywords: endotracheal tube; face mask; helmet; noninvasive ventilation; patient-ventilator interaction; pressure-support ventilation