title: End-Tidal Carbon Dioxide Measurement during Pediatric Polysomnography: Signal Quality, Association with Apnea Severity, and Prediction of Neurobehavioral Outcomes.
abstract: OBJECTIVE
  To identify the role of end-tidal carbon dioxide (EtCO2) monitoring during polysomnography in evaluation of children with obstructive sleep apnea syndrome (OSAS), including the correlation of EtCO2 with other measures of OSAS and prediction of changes in cognition and behavior after adenotonsillectomy.
  
  
  METHODS
  Analysis of screening and endpoint data from the Childhood Adenotonsillectomy Trial, a randomized, controlled, multicenter study comparing early adenotonsillectomy (eAT) to watchful waiting/supportive care (WWSC) in children with OSAS.
  
  
  METHODS
  Multisite clinical referral settings.
  
  
  METHODS
  Children, ages 5.0 to 9.9 y with suspected sleep apnea.
  
  
  METHODS
  eAT or WWSC.
  
  
  RESULTS
  Quality EtCO2 waveforms were present for ≥ 75% of total sleep time (TST) in 876 of 960 (91.3%) screening polysomnograms. Among the 322 children who were randomized, 55 (17%) met pediatric criteria for hypoventilation. The mean TST with EtCO2 > 50 mmHg was modestly correlated with apnea-hypopnea index (AHI) (r = 0.33; P < 0.0001) and with oxygen saturation ≤ 92% (r = 0.26; P < 0.0001). After adjusting for AHI, obesity, and other factors, EtCO2 > 50 mmHg was higher in African American children than others. The TST with EtCO2 > 50 mmHg decreased significantly more after eAT than WWSC. In adjusted analyses, baseline TST with EtCO2 > 50 mmHg did not predict postoperative changes in cognitive and behavioral measurements.
  
  
  CONCLUSIONS
  Among children with suspected obstructive sleep apnea syndrome, overnight end-tidal carbon dioxide (EtCO2) levels are weakly to modestly correlated with other polysomnographic indices and therefore provide independent information on hypoventilation. EtCO2 levels improve with adenotonsillectomy but are not as responsive as AHI and do not provide independent prediction of cognitive or behavioral response to surgery.
  
  
  BACKGROUND
  Childhood Adenotonsillectomy Study for Children with OSAS (CHAT). ClinicalTrials.gov Identifier #NCT00560859.
authors.affiliation: Department of Pediatrics, Saint Louis University, St. Louis, MO.
authors.forename: Shalini
authors.initials: S
authors.lastname: Paruthi
authors.affiliation: Department of Pediatrics, Rainbow Babies & Children's Hospital, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, Cleveland, OH.
authors.forename: Carol L
authors.initials: CL
authors.lastname: Rosen
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital; University of Pennsylvania, Philadelphia, PA.|Department of Biostatistics, Harvard School of Public Health; University of Pennsylvania, Philadelphia, PA.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Division of Sleep Medicine, Brigham and Women's Hospital; University of Pennsylvania, Philadelphia, PA.
authors.forename: Jia
authors.initials: J
authors.lastname: Weng
authors.affiliation: Department of Pediatrics, Sleep Center, Children's Hospital of Philadelphia; University of Pennsylvania, Philadelphia, PA.
authors.forename: Carole L
authors.initials: CL
authors.lastname: Marcus
authors.affiliation: Department of Neurology and Sleep Disorders Center, University of Michigan, Ann Arbor, MI.
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Chervin
authors.affiliation: Departments of Otolaryngology and Neurology and Sleep Disorders Center, University of Michigan, Ann Arbor, MI.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Stanley
authors.affiliation: Division of Respiratory Diseases, Boston Children's Hospital, Boston, MA.
authors.forename: Eliot S
authors.initials: ES
authors.lastname: Katz
authors.affiliation: Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH.
authors.forename: Raouf
authors.initials: R
authors.lastname: Amin
authors.affiliation: Departments of Medicine, Brigham and Women's Hospital and Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Susan
authors.initials: S
authors.lastname: Redline
mesh_terms: D000233:Adenoidectomy; D001741:Black or African American; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism*; D002648:Child; D002652:Child Behavior; D002675:Child, Preschool; D003071:Cognition; D005260:Female; D006801:Humans; D007040:Hypoventilation / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000150:complications; D017286:Polysomnography; D011184:Postoperative Period; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D013990:Tidal Volume; D014068:Tonsillectomy; D057832:Watchful Waiting
chemical_list: D002245:Carbon Dioxide
keywords: CO2; capnography; end-tidal; hypercapnia; hypoventilation; pediatric; polysomnogram; sleep apnea