title: Development and validation of a cerebral oximeter capable of absolute accuracy.
abstract: OBJECTIVE
  Cerebral oximetry may be a valuable monitor, but few validation data are available, and most report the change from baseline rather than absolute accuracy, which may be affected by individuals whose oximetric values are outside the expected range. The authors sought to develop and validate a cerebral oximeter capable of absolute accuracy.
  
  
  METHODS
  An in vivo research study.
  
  
  METHODS
  A university human physiology laboratory.
  
  
  METHODS
  Healthy human volunteers were enrolled in calibration and validation studies of 2 cerebral oximetric sensors, the Nonin 8000CA and 8004CA. The 8000CA validation study identified 5 individuals with atypical cerebral oxygenation values; their data were used to design the 8004CA sensor, which subsequently underwent calibration and validation.
  
  
  METHODS
  Volunteers were taken through a stepwise hypoxia protocol to a minimum saturation of peripheral oxygen. Arteriovenous saturation (70% jugular bulb venous saturation and 30% arterial saturation) at 6 hypoxic plateaus was used as the reference value for the cerebral oximeter. Absolute accuracy was defined using a combination of the bias and precision of the paired saturations (A(RMS)).
  
  
  RESULTS
  In the validation study for the 8000CA sensor (n = 9, 106 plateaus), relative accuracy was an A(RMS) of 2.7, with an absolute accuracy of 8.1, meeting the criteria for a relative (trend) monitor, but not an absolute monitor. In the validation study for the 8004CA sensor (n = 11, 119 plateaus), the A(RMS) of the 8004CA was 4.1, meeting the prespecified success criterion of <5.0.
  
  
  CONCLUSIONS
  The Nonin cerebral oximeter using the 8004CA sensor can provide absolute data on regional cerebral saturation compared with arteriovenous saturation, even in subjects previously shown to have values outside the normal population distribution curves.
authors.affiliation: Department of Anesthesiology, Duke University, Durham, NC, USA. david.macleod@duke.edu
authors.forename: David B
authors.initials: DB
authors.lastname: MacLeod
authors.forename: Keita
authors.initials: K
authors.lastname: Ikeda
authors.forename: Charles
authors.initials: C
authors.lastname: Vacchiano
authors.forename: Aaron
authors.initials: A
authors.lastname: Lobbestael
authors.forename: Joyce A
authors.initials: JA
authors.lastname: Wahr
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Shaw
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010092:Oximetry / Q000592:standards* / Q000639:trends*; D011446:Prospective Studies; D055815:Young Adult