title: Cross-sectional changes in lung volume measured by electrical impedance tomography are representative for the whole lung in ventilated preterm infants.
abstract: OBJECTIVE
  Electrical impedance tomography measures lung volume in a cross-sectional slice of the lung. Whether these cross-sectional volume changes are representative of the whole lung has only been investigated in adults, showing conflicting results. This study aimed to compare cross-sectional and whole lung volume changes using electrical impedance tomography and respiratory inductive plethysmography.
  
  
  METHODS
  A prospective, single-center, observational, nonrandomized study.
  
  
  METHODS
  The study was conducted in a neonatal ICU in the Netherlands.
  
  
  METHODS
  High-frequency ventilated preterm infants with respiratory distress syndrome.
  
  
  METHODS
  Cross-sectional and whole lung volume changes were continuously and simultaneously measured by, respectively, electrical impedance tomography and respiratory inductive plethysmography during a stepwise recruitment procedure. End-expiratory lung volume changes were assessed by mapping the inflation and deflation limbs using both the pressure/impedance and pressure/inductance pairs and characterized by calculating the inflection points. In addition, oscillatory tidal volume changes were assessed at each pressure step.
  
  
  RESULTS
  Twenty-three infants were included in the study. Of these, eight infants had to be excluded because the quality of the registration was insufficient for analysis (two electrical impedance tomography and six respiratory inductive plethysmography). In the remaining 15 infants (gestational age 28.0 ± 2.6 wk; birth weight 1,027 ± 514 g), end-expiratory lung volume changes measured by electrical impedance tomography were significantly correlated to respiratory inductive plethysmography measurements in 12 patients (mean r = 0.93 ± 0.05). This was also true for the upper inflection point on the inflation (r = 0.91, p < 0.01) and deflation limb (r = 0.83, p < 0.01). In 13 patients, impedance and inductance data also correlated significantly on oscillatory tidal volume/pressure relationships (mean r = 0.81 ± 0.18).
  
  
  CONCLUSIONS
  This study shows that cross-sectional lung volume changes measured by electrical impedance tomography are representative for the whole lung and that this concept also applies to newborn infants.
authors.affiliation: 1Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands. 2Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Germany.
authors.forename: Pauline S
authors.initials: PS
authors.lastname: van der Burg
authors.forename: Martijn
authors.initials: M
authors.lastname: Miedema
authors.forename: Frans H
authors.initials: FH
authors.lastname: de Jongh
authors.forename: Inez
authors.initials: I
authors.lastname: Frerichs
authors.forename: Anton H
authors.initials: AH
authors.lastname: van Kaam
mesh_terms: D001823:Body Composition; D017097:Electric Impedance; D005260:Female; D006612:High-Frequency Ventilation / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D007363:Intensive Care Units, Neonatal; D008168:Lung / Q000033:anatomy & histology* / Q000502:physiology; D008176:Lung Volume Measurements / Q000295:instrumentation* / Q000379:methods; D008297:Male; D010991:Plethysmography / Q000295:instrumentation / Q000379:methods*; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D018709:Statistics, Nonparametric; D013990:Tidal Volume / Q000502:physiology; D014054:Tomography / Q000379:methods