title: Volume Oscillations Delivered to a Lung Model Using 4 Different Bubble CPAP Systems.
abstract: BACKGROUND
  High-frequency pressure oscillations created by gas bubbling through an underwater seal during bubble CPAP may enhance ventilation and aid in lung recruitment in premature infants. We hypothesized that there are no differences in the magnitude of oscillations in lung volume (ΔV) in a preterm neonatal lung model when different bubble CPAP systems are used.
  
  
  METHODS
  An anatomically realistic replica of an infant nasal airway model was attached to a Silastic test lung sealed within a calibrated plethysmograph. Nasal prongs were affixed to the simulated neonate and supported using bubble CPAP systems set at 6 cm H2O. ΔV was calculated using pressure measurements obtained from the plethysmograph.
  
  
  RESULTS
  The Fisher & Paykel Healthcare bubble CPAP system provided greater ΔV than any of the other devices at all of the respective bias flows (P < .05). The Fisher & Paykel Healthcare and Babi.Plus systems generally provided ΔV at lower frequencies than the other bubble CPAP systems. The magnitude of ΔV increased at bias flows of > 4 L/min in the Fisher & Paykel Healthcare, Airways Development, and homemade systems, but appeared to decrease as bias flow increased with the Babi.Plus system.
  
  
  CONCLUSIONS
  The major finding of this study is that bubble CPAP can provide measureable ventilation effects in an infant lung model. We speculate that the differences noted in ΔV between the different devices are a combination of the circuit/nasal prong configuration, bubbler configuration, and frequency of oscillations. Additional testing is needed in spontaneously breathing infants to determine whether a physiologic benefit exists when using the different bubble CPAP systems.
authors.affiliation: Center for Developmental Therapeutics, Seattle Children's Hospital Research Institute, Seattle, Washington. jpoli43@gmail.com.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Poli
authors.affiliation: Center for Developmental Therapeutics, Seattle Children's Hospital Research Institute, Seattle, Washington. University of Washington School of Medicine, Seattle, Washington.
authors.forename: C Peter
authors.initials: CP
authors.lastname: Richardson
authors.affiliation: Center for Developmental Therapeutics, Seattle Children's Hospital Research Institute, Seattle, Washington. Respiratory Care Department, Children's Hospital and Regional Medical Center, Seattle, Washington.
authors.forename: Robert M
authors.initials: RM
authors.lastname: DiBlasi
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000295:instrumentation*; D004867:Equipment Design; D006612:High-Frequency Ventilation / Q000295:instrumentation*; D006801:Humans; D007231:Infant, Newborn; D008954:Models, Biological; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology / Q000628:therapy*; D013990:Tidal Volume; D012122:Ventilators, Mechanical / Q000592:standards*; D014939:Work of Breathing / Q000502:physiology*
keywords: bubble CPAP; flow dependence; lung model; nasal prongs; noninvasive ventilation; respiratory distress syndrome