title: Effects of Multiple Ventilation Courses and Duration of Mechanical Ventilation on Respiratory Outcomes in Extremely Low-Birth-Weight Infants.
abstract: OBJECTIVE
  Extubation failure is common in extremely preterm infants. The current paucity of data on the adverse long-term respiratory outcomes associated with reinitiation of mechanical ventilation prevents assessment of the risks and benefits of a trial of extubation in this population.
  
  
  OBJECTIVE
  To evaluate whether exposure to multiple courses of mechanical ventilation increases the risk of adverse respiratory outcomes before and after adjustment for the cumulative duration of mechanical ventilation.
  
  
  METHODS
  We performed a retrospective cohort study of extremely low-birth-weight (ELBW; birth weight <1000 g) infants born from January 1, 2006, through December 31, 2012, who were receiving mechanical ventilation. Analysis was conducted between November 2014 and February 2015. Data were obtained from the Alere Neonatal Database.
  
  
  METHODS
  The primary study exposures were the cumulative duration of mechanical ventilation and the number of ventilation courses.
  
  
  METHODS
  The primary outcome was bronchopulmonary dysplasia (BPD) among survivors. Secondary outcomes were death, use of supplemental oxygen at discharge, and tracheostomy.
  
  
  RESULTS
  We identified 3343 ELBW infants, of whom 2867 (85.8%) survived to discharge. Among the survivors, 1695 (59.1%) were diagnosed as having BPD, 856 (29.9%) received supplemental oxygen at discharge, and 31 (1.1%) underwent tracheostomy. Exposure to a greater number of mechanical ventilation courses was associated with a progressive increase in the risk of BPD and use of supplemental oxygen at discharge. Compared with a single ventilation course, the adjusted odds ratios for BPD ranged from 1.88 (95% CI, 1.54-2.31) among infants with 2 ventilation courses to 3.81 (95% CI, 2.88-5.04) among those with 4 or more courses. After adjustment for the cumulative duration of mechanical ventilation, the odds of BPD were only increased among infants exposed to 4 or more ventilation courses (adjusted odds ratio, 1.44; 95% CI, 1.04-2.01). The number of ventilation courses was not associated with increased risk of supplemental oxygen use at discharge after adjustment for the length of ventilation. A greater number of ventilation courses did not increase the risk of tracheostomy.
  
  
  CONCLUSIONS
  Among ELBW infants, a longer cumulative duration of mechanical ventilation largely accounts for the increased risk of chronic respiratory morbidity associated with reinitiation of mechanical ventilation. These results support attempts of extubation in ELBW infants receiving mechanical ventilation on low ventilator settings, even when success is not guaranteed.
authors.affiliation: Division of Neonatology, Department of Pediatrics, The Children's Hospital of Philadelphia and The University of Pennsylvania School of Medicine, Philadelphia.
authors.forename: Erik A
authors.initials: EA
authors.lastname: Jensen
authors.affiliation: Division of Neonatology, Department of Pediatrics, The Children's Hospital of Philadelphia and The University of Pennsylvania School of Medicine, Philadelphia.
authors.forename: Sara B
authors.initials: SB
authors.lastname: DeMauro
authors.affiliation: Alere Inc, Waltham, Massachusetts.
authors.forename: Michael
authors.initials: M
authors.lastname: Kornhauser
authors.affiliation: Division of Neonatology, Nemours/Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Zubair H
authors.initials: ZH
authors.lastname: Aghai
authors.affiliation: Division of Neonatology, Nemours/Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania.
authors.forename: Jay S
authors.initials: JS
authors.lastname: Greenspan
authors.affiliation: Division of Neonatology, Department of Pediatrics, The Children's Hospital of Philadelphia and The University of Pennsylvania School of Medicine, Philadelphia.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Dysart
mesh_terms: D060666:Airway Extubation / Q000706:statistics & numerical data*; D001997:Bronchopulmonary Dysplasia / Q000453:epidemiology* / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D012189:Retrospective Studies; D012307:Risk Factors; D014139:Tracheostomy / Q000706:statistics & numerical data