title: The state of systemic circulation, collapsed or preserved defines the need for hyperoxic or normoxic resuscitation in neonatal mice with hypoxia-ischemia.
abstract: BACKGROUND
  The return of spontaneous circulation (ROSC) is a primary goal of resuscitation. For neonatal resuscitation the International Liaison Committee on Resuscitation (ILCOR) recommends oxygen concentrations ranging from 21% to 100%.
  
  
  OBJECTIVE
  This study (a) compared the efficacy of resuscitation with room air (RA) or 100% O(2) in achieving ROSC in 46 neonatal mice with circulatory collapse induced by lethal hypoxia-ischemia (HI) and (b) determined whether re-oxygenation with RA or 100% O(2) alters the extent of HI cerebral injury in mice with preserved systemic circulation (n=31). We also compared changes in generation of reactive oxygen species (ROS) in cerebral mitochondria in response to re-oxygenation with RA or 100% O(2).
  
  
  RESULTS
  In HI-mice with collapsed circulation re-oxygenation with 100% O(2) versus RA resulted in significantly greater rate of ROSC. In HI-mice with preserved systemic circulation and regional (unilateral) cerebral ischemia the restoration of cerebral blood flow was significantly faster upon re-oxygenation with 100% O(2), than RA. However, no difference in the extent of brain injury was detected. Regardless of the mode of re-oxygenation, reperfusion in these mice was associated with markedly accelerated ROS production in brain mitochondria.
  
  
  CONCLUSIONS
  In murine HI associated with circulatory collapse the resuscitation limited to re-oxygenation with 100% O(2) is superior to the use of RA in achievement of the ROSC. However, in HI-mice with preserved systemic circulation hyperoxic re-oxygenation has no benefit over the normoxic brain recovery.
authors.affiliation: Department of Pediatrics, Division of Neonatology, Columbia University College of Physicians and Surgeons, 3959 Broadway, BHS1-115, Columbia University Medical Center, New York, NY 10032, USA.
authors.forename: Dzmitry
authors.initials: D
authors.lastname: Matsiukevich
authors.forename: Tara M
authors.initials: TM
authors.lastname: Randis
authors.forename: Irina
authors.initials: I
authors.lastname: Utkina-Sosunova
authors.forename: Richard A
authors.initials: RA
authors.lastname: Polin
authors.forename: Vadim S
authors.initials: VS
authors.lastname: Ten
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001775:Blood Circulation; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology* / Q000628:therapy*; D051379:Mice; D008810:Mice, Inbred C57BL; D010102:Oxygen Inhalation Therapy; D012151:Resuscitation / Q000379:methods*