title: The association between the end tidal alveolar dead space fraction and mortality in pediatric acute hypoxemic respiratory failure.
abstract: OBJECTIVE
  To investigate the relationship of markers of oxygenation, PaO2/FIO2 ratio, SpO2/FIO2 ratio, oxygenation index, oxygen saturation index, and dead space (end tidal alveolar dead space fraction) with mortality in children with acute hypoxemic respiratory failure.
  
  
  METHODS
  Retrospective.
  
  
  METHODS
  Single-center tertiary care pediatric intensive care unit.
  
  
  METHODS
  Ninety-five mechanically ventilated children with a PaO2/FIO2 ratio <300 within 24 hrs of the initiation of mechanical ventilation.
  
  
  METHODS
  None.
  
  
  RESULTS
  The end tidal alveolar dead space fraction, PaO2/FIO2 ratio, SpO2/FIO2 ratio, oxygenation index, and oxygen saturation index were all associated with mortality (p < .02). There was a small correlation between the end tidal alveolar dead space fraction and decreasing PaO2/FIO2 (r2 = .21) and SpO2/FIO2 ratios (r2 = .22), and increasing oxygenation index (r2= .25) and oxygen saturation index (r2 = .24). In multivariate logistic regression modeling, the end tidal alveolar dead space fraction was independently associated with mortality (p < .02). Oxygenation index, oxygen saturation index, and the end tidal alveolar dead space fraction were all acceptable discriminators of mortality with receiver operating characteristic plot area under the curves ≥ 0.7.
  
  
  CONCLUSIONS
  In pediatric acute hypoxemic respiratory failure, easily obtainable pulmonary specific markers of disease severity (SpO2/FIO2 ratio, oxygen saturation index, and the end tidal alveolar dead space fraction) may be useful for the early identification of children at high risk of death. Furthermore, the end tidal alveolar dead space fraction should be considered for risk stratification of children with acute hypoxemic respiratory failure, given that it was independently associated with mortality.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA, USA. aghuman@chla.usc.edu
authors.forename: Anoopindar K
authors.initials: AK
authors.lastname: Ghuman
authors.forename: Christopher J L
authors.initials: CJ
authors.lastname: Newth
authors.forename: Robinder G
authors.initials: RG
authors.lastname: Khemani
mesh_terms: D000208:Acute Disease; D055371:Acute Lung Injury / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016638:Critical Illness / Q000401:mortality / Q000628:therapy; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D007223:Infant; D015278:Intensive Care Units, Pediatric; D008297:Male; D011379:Prognosis; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012372:ROC Curve; D012121:Respiration, Artificial; D012126:Respiratory Dead Space / Q000502:physiology*; D012131:Respiratory Insufficiency / Q000175:diagnosis* / Q000401:mortality* / Q000628:therapy; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013990:Tidal Volume / Q000502:physiology