title: A new approach to an old hypothesis; phototherapy does not affect ductal patency via PGE2 and PGI2.
abstract: OBJECTIVE
  Numerous investigations have demonstrated that phototherapy (PT) directly or indirectly causes ductal patency by photorelaxation effect. In this observational study, we aimed to assess the effect of PT on the incidence of patent ductus arteriosus (PDA) together with prostaglandins (PGE2) and (PGI2) levels in preterm infants.
  
  
  METHODS
  Preterm infants whose gestational age<34 weeks and who required PT in the first 3 d of life were enrolled in this prospective study. The clinical signs of PDA, the data of detailed echocardiographic study were recorded and plasma PGE2 and PGI2 levels were measured before and after PT. The outcome measures were the status of ductus arteriosus and alterations of PGE2 and PGI2 levels under the effect of PT.
  
  
  RESULTS
  A total of 44 preterm infants were enrolled in the study, of these 21 (47.7%) were in Group 1 (Non-PDA Group) and 23 (52.3%) were in Group 2 (PDA Group). After PT, ductal reopening occurred in three infants (14.3%) in Group 1, while ductus closed in four infants in Group 2 (17.3%). PT does not seem to effect ductal patency for both groups (p=0.250 and p=0.125, respectively). PGE2 levels were not different before and after PT for both groups (p=0.087, p=0.408, respectively). However, PGI2 levels were significantly decreased after PT in both groups (p=0.006, and p=0.003, respectively).
  
  
  CONCLUSIONS
  There was no effect of PT on ductal patency. We can conclude that PGs were eliminated simultaneously with ductal closure and photorelaxation effect did not influence PG levels.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Faculty of Medicine, Hacettepe University , Ankara , Turkey .
authors.forename: Ozge
authors.initials: O
authors.lastname: Surmeli-Onay
authors.forename: Murat
authors.initials: M
authors.lastname: Yurdakok
authors.forename: Tevfik
authors.initials: T
authors.lastname: Karagoz
authors.forename: Pinar
authors.initials: P
authors.lastname: Erkekoglu
authors.forename: Ilker
authors.initials: I
authors.lastname: Ertugrul
authors.forename: Sahin
authors.initials: S
authors.lastname: Takci
authors.forename: Belma Kocer
authors.initials: BK
authors.lastname: Giray
authors.forename: Hayrettin Hakan
authors.initials: HH
authors.lastname: Aykan
authors.forename: Ayse
authors.initials: A
authors.lastname: Korkmaz
authors.forename: Sule
authors.initials: S
authors.lastname: Yigit
mesh_terms: D016022:Case-Control Studies; D015232:Dinoprostone / Q000097:blood*; D004373:Ductus Arteriosus / Q000528:radiation effects*; D004374:Ductus Arteriosus, Patent / Q000209:etiology*; D011464:Epoprostenol / Q000097:blood*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D010789:Phototherapy; D011446:Prospective Studies
chemical_list: D011464:Epoprostenol; D015232:Dinoprostone
keywords: Patent ductus arteriosus; phototherapy; preterm infant; prostaglandin