title: Have the boundaries of the 'grey zone' of perinatal resuscitation changed for extremely preterm infants over 20 years?
abstract: OBJECTIVE
  To determine the boundaries of the grey zone of discretionary resuscitation over the past 20 years.
  
  
  BACKGROUND
  As the likelihood of survival improves over time, the BW- and GA-specific boundaries of discretionary nonresuscitation should fall.
  
  
  OBJECTIVE
  Between 1988 and 2008 reductions in BW- and GA-specific mortality would drive a parallel reduction in BW and GA boundaries of discretionary resuscitation.
  
  
  METHODS
  We determined the likelihood of resuscitation and survival to NICU discharge for all infants born <700 g or <26 gestational weeks from 1988 to 2008. In addition, for 1988, 1993, 1998, 2003 and 2008, we determined the BW and GA for the 10 smallest infants who were resuscitated, and the 10 largest infants who were not resuscitated. We excluded any infant born with congenital anomaly.
  
  
  RESULTS
  Mortality fell from 80% in 1988 to 28% in 2008, and as expected, the percentage who were resuscitated rose from 63% in 1988-93 to 95% in 2004-2008. However, unexpectedly, over the 20-year study period, the smallest infants who were resuscitated despite extreme immaturity did not change (450-550 g and 23-24 weeks) and the largest infants not resuscitated did not change (600-700 g and 23-24 weeks.
  
  
  CONCLUSIONS
  Neither the BW nor GA boundaries of the grey zone of discretionary resuscitation have fallen over the past 20 years. Factors guiding resuscitation at the border of viability are complex and incompletely understood.
authors.affiliation: Department of Pediatrics, The University of Chicago, Chicago, IL, USA.
authors.forename: J
authors.initials: J
authors.lastname: Condie
authors.forename: L
authors.initials: L
authors.lastname: Caldarelli
authors.forename: L
authors.initials: L
authors.lastname: Tarr
authors.forename: C
authors.initials: C
authors.lastname: Gray
authors.forename: T
authors.initials: T
authors.lastname: Rodriquez
authors.forename: J
authors.initials: J
authors.lastname: Lantos
authors.forename: W
authors.initials: W
authors.lastname: Meadow
mesh_terms: D001724:Birth Weight; D002985:Clinical Protocols; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D062071:Infant, Extremely Premature; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000401:mortality / Q000628:therapy*; D015931:Intensive Care, Neonatal; D018579:Patient Selection; D012151:Resuscitation; D012189:Retrospective Studies; D014481:United States