title: Effects of low oxygen saturation limits on the ductus arteriosus in extremely low birth weight infants.
abstract: OBJECTIVE
  Postnatal increase in oxygen promotes constriction of the patent ductus arteriosus (PDA). According to the findings of prospective observational studies, the clinical practice of targeting lower fractional oxygen saturation between 70 and 90% has been associated with a reduced incidence of severe retinopathy of prematurity (ROP) without affecting survival or neurodevelopmental disability at 1 year of age. Our objective was to investigate the impact of the use of a lower oxygen saturation target range on the incidence of early hemodynamically significant PDA (hsPDA) and the need for ductal ligation in extremely low birth weight (ELBW, <1000 g) infants.
  
  
  METHODS
  In this retrospective study, we analyzed data from 263 ELBW infants managed 4 years before (episode I: target oxygen saturation 89 to 94%) and after (episode II: target oxygen saturation 83 to 89%) implementation of the use of lower oxygen saturation limits in two neonatal intensive care units. Infants with a birth weight of 1000 to 1500 g were managed with the same oxygen saturation target range (89 to 94%) during both episodes, and they served as controls. Parametric and nonparametric tests were used as appropriate and multivariate logistic regression models were used to correct for confounders.
  
  
  RESULTS
  There was an increase in the incidence of hsPDA (63.2 vs 74.8%, P=0.043), without an increase in the need for surgical ligation (24.2 vs 29.9%, P=0.3) after implementation of the lower oxygen saturation target range policy. After adjusting for confounders, there was an increase in the odds of having an hsPDA (odds ratio (OR) 1.77, 95% confidence interval (CI) (1.03 to 3.06), P=0.04) but the odds for ductal ligation did not change in episode II (OR 1.25, 95% CI (0.70 to 2.25), P=0.4). The incidence of ROP > or = stage III (50.7 vs 15.7%; P<0.0001) and the need for laser ablation (33.8% vs 8.7%; P<0.0001) were significantly reduced. There was no change in the incidence of hsPDA or ductal ligation in the control group.
  
  
  CONCLUSIONS
  Targeting lower oxygen saturation limits to minimize periods of hyperoxemia in ELBW infants reduced the incidence of severe ROP and the need for laser ablation. The incidence of early hsPDA was increased; however, final closure rate and the incidence of surgical ligation of the ductus arteriosus were not affected.
authors.affiliation: Department of Pediatrics, Neonatal-Perinatal Medicine, The Children's Hospital, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. snoori@ouhsc.edu
authors.forename: S
authors.initials: S
authors.lastname: Noori
authors.forename: D
authors.initials: D
authors.lastname: Patel
authors.forename: P
authors.initials: P
authors.lastname: Friedlich
authors.forename: B
authors.initials: B
authors.lastname: Siassi
authors.forename: I
authors.initials: I
authors.lastname: Seri
authors.forename: R
authors.initials: R
authors.lastname: Ramanathan
mesh_terms: D001784:Blood Gas Analysis; D006348:Cardiac Surgical Procedures; D019091:Critical Pathways; D004374:Ductus Arteriosus, Patent / Q000601:surgery / Q000628:therapy*; D006439:Hemodynamics; D006801:Humans; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D008026:Ligation; D016017:Odds Ratio; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects / Q000379:methods*; D012178:Retinopathy of Prematurity / Q000209:etiology / Q000517:prevention & control*; D012189:Retrospective Studies