title: Noninvasive Estimation of Arterial CO2 From End-Tidal CO2 in Mechanically Ventilated Children: The GRAeDIENT Pilot Study.
abstract: The aim of our pilot study was to develop a model to better predict Paco2 in mechanically ventilated children using noninvasive parameters including volumetric capnography.
  
  
  
  Prospective clinical pilot study.
  
  
  
  Level III PICU.
  
  
  
  Sixty-five mechanically ventilated children.
  
  
  
  None.
  
  
  
  We conducted a prospective clinical pilot study that included all children admitted to the PICU (< 18 yr; weight, > 3 kg; mechanically ventilated, > 6 hr; with an arterial line). A predictive model for PaCO2 was developed using linear multivariable regression. Among the data collected in PICU patients, candidate predictors of PaCO2 were defined by a panel of experts and included end-tidal partial pressure of carbon dioxide, ventilation parameters, and data resulting from the analysis of volumetric capnogram recorded 5 minutes before an arterial blood gas. Children with tidal volume less than 30 mL were excluded because of technical limits.
  
  
  
  A total of 65 children (43 boys, 65%) (65 [21-150] mo old) were analyzed. By linear multivariable regression, the best model included the mean airway pressure, end-tidal partial pressure of carbon dioxide, FIO2, and the capnographic index with an R equal to 0.90, p value less than 0.001. After correction, 95% (n = 62) of children had an estimated PaCO2 at ± 5 mm Hg.
  
  
  
  Our model developed provides an accurate estimation of the PaCO2 using end-tidal CO2 and noninvasive variables. Studies are needed to validate the equation in PICUs.
authors.affiliation: 1Pediatric Intensive Care Unit, Department of Pediatrics, CHU Sainte-Justine, Montreal, QC, Canada.2Pediatric Intensive Care Unit, Department of Pediatrics, HFME-Hospices Civils de Lyon, Bron, France.3Pediatric Intensive Care Unit, Department of Pediatrics, CHU-Nantes, Nantes, France.4Pediatric Intensive Care Unit, Department of Pediatrics, Hôpitaux Universitaires Paris-Sud AP-HP, Kremlin-Bicêtre, Paris.5Research Center, CHU Sainte-Justine, Montreal, QC, Canada.
authors.forename: Florent
authors.initials: F
authors.lastname: Baudin
authors.forename: Pierre
authors.initials: P
authors.lastname: Bourgoin
authors.forename: David
authors.initials: D
authors.lastname: Brossier
authors.forename: Sandrine
authors.initials: S
authors.lastname: Essouri
authors.forename: Guillaume
authors.initials: G
authors.lastname: Emeriaud
authors.forename: Marc
authors.initials: M
authors.lastname: Wysocki
authors.forename: Philippe
authors.initials: P
authors.lastname: Jouvet
mesh_terms: D000293:Adolescent; D001158:Arteries; D015415:Biomarkers / Q000378:metabolism; D001784:Blood Gas Analysis; D019296:Capnography; D002245:Carbon Dioxide / Q000097:blood* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D010865:Pilot Projects; D011446:Prospective Studies; D012121:Respiration, Artificial; D013990:Tidal Volume
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide