title: Timing of antenatal corticosteroids and neonatal pulmonary mechanics.
abstract: OBJECTIVE
  We sought to compare lung mechanics in infants treated with multiple courses of antenatal corticosteroids with those in matched control infants delivered >7 days from dosing and those of matched untreated infants.
  
  
  METHODS
  Eighteen infants who received multiple courses of corticosteroids and were delivered within 7 days of dosing were matched with 18 infants who received 1 course of corticosteroids >7 days before delivery (remote) and 18 untreated infants. Respiratory compliance and functional residual capacity were measured within 36 hours. Differences were compared by analysis of variance.
  
  
  RESULTS
  Infant demographics were similar. Respiratory compliance was higher in the multiple-course group than in the remote or untreated group (P <.02). Functional residual capacity was higher in the multiple-course group than in the untreated group (P <.05) but similar to that found in the remote group.
  
  
  CONCLUSIONS
  Babies delivered after multiple courses of corticosteroids and within 7 days of dosing demonstrated improved respiratory compliance compared with untreated and remotely treated infants. This suggests that the enzyme system responsible for surfactant production can be repetitively induced despite prior treatment with corticosteroids. The increased functional residual capacity in remotely treated infants may reflect a maturation of lung architecture independent of surfactant production.
authors.affiliation: Department of Pediatrics and Obstetrics, Sacred Heart Hospital, University of Florida, Pensacola, Florida, USA.
authors.forename: C
authors.initials: C
authors.lastname: McEvoy
authors.forename: S
authors.initials: S
authors.lastname: Bowling
authors.forename: K
authors.initials: K
authors.lastname: Williamson
authors.forename: J
authors.initials: J
authors.lastname: Collins
authors.forename: L
authors.initials: L
authors.lastname: Tolaymat
authors.forename: J
authors.initials: J
authors.lastname: Maher
mesh_terms: D001623:Betamethasone / Q000008:administration & dosage* / Q000627:therapeutic use; D036861:Delivery, Obstetric; D004334:Drug Administration Schedule; D005333:Fetus / Q000187:drug effects*; D005652:Functional Residual Capacity / Q000187:drug effects; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D008168:Lung / Q000502:physiology*; D008170:Lung Compliance / Q000187:drug effects; D011446:Prospective Studies; D015656:Respiratory Mechanics; D013997:Time Factors
chemical_list: D005938:Glucocorticoids; D001623:Betamethasone