title: Effect of Minimally Invasive Surfactant Therapy on Lung Volume and Ventilation in Preterm Infants.
abstract: OBJECTIVE
  To assess the changes in (regional) lung volume and gas exchange during minimally invasive surfactant therapy (MIST) in preterm infants with respiratory distress syndrome.
  
  
  METHODS
  In this prospective observational study, infants requiring a fraction of inspired oxygen (FiO2) ≥ 0.30 during nasal continuous positive airway pressure of 6 cmH2O were eligible for MIST. Surfactant (160-240 mg/kg) was administered in supine position in 1-3 minutes via an umbilical catheter placed 2 cm below the vocal cords. Changes in end-expiratory lung volume (EELV), tidal volume, and its distribution were recorded continuously with electrical impedance tomography before and up to 60 minutes after MIST. Changes in transcutaneous oxygen saturation (SpO2) and partial carbon dioxide pressure, FiO2, respiratory rate, and minute ventilation were recorded.
  
  
  RESULTS
  A total of 16 preterm infants were included. One patient did not finish study protocol because of severe apnea 10 minutes after MIST. In the remaining infants (gestational age 29.8 ± 2.8 weeks, body weight 1545 ± 481 g) EELV showed a rapid and sustained increase, starting in the dependent lung regions, followed by the nondependent regions approximately 5 minutes later. Oxygenation, expressed as the SpO2/FiO2 ratio, increased from 233 (IQR 206-257) to 418 (IQR 356-446) after 60 minutes (P < .001). This change was significantly correlated with the change in EELV (ρ = 0.70, P < .01). Tidal volume and minute volume decreased significantly after MIST, but transcutaneous partial carbon dioxide pressure was comparable with pre-MIST values. Ventilation distribution remained unchanged.
  
  
  CONCLUSIONS
  MIST results in a rapid and homogeneous increase in EELV, which is associated with an improvement in oxygenation.
authors.affiliation: Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands. Electronic address: p.s.burgvander@amc.uva.nl.
authors.forename: Pauline S
authors.initials: PS
authors.lastname: van der Burg
authors.affiliation: Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Frans H
authors.initials: FH
authors.lastname: de Jongh
authors.affiliation: Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Miedema
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
authors.forename: Inez
authors.initials: I
authors.lastname: Frerichs
authors.affiliation: Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Anton H
authors.initials: AH
authors.lastname: van Kaam
mesh_terms: D001784:Blood Gas Analysis; D045422:Continuous Positive Airway Pressure / Q000379:methods; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D011446:Prospective Studies; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000627:therapeutic use*; D012127:Respiratory Distress Syndrome, Newborn / Q000503:physiopathology / Q000628:therapy*; D013990:Tidal Volume / Q000502:physiology*; D014054:Tomography
chemical_list: D011663:Pulmonary Surfactants