title: Pulse oximeter performance during desaturation and resaturation: a comparison of seven models.
abstract: OBJECTIVE
  To compare pulse oximeter performance during induced hypoxemia.
  
  
  METHODS
  Prospective investigation in human volunteers.
  
  
  METHODS
  Laboratory facility at a university medical center.
  
  
  METHODS
  8 unanesthetized, healthy ASA physical status I volunteers.
  
  
  METHODS
  We evaluated the accuracy and response times of seven popular pulse oximeters during induced hypoxemia. Arterial blood fractional oxygen saturation (SaO2) measurements were performed simultaneously and considered a gold standard.
  
  
  RESULTS
  All oximeters were accurate (+/-2%) while subjects were breathing room air. During maximal hypoxemia (induced by breathing a FIO2 = 10% in nitrogen), large differences were noted between oxygen saturation as measured by pulse oximetry (SpO2) and SaO2 values, with pulse oximeters consistently underreporting SpO2 when actual SaO2 values were 75% or less. The Ohmeda 3740 (Ohmeda, Boulder, CO) using an ear probe was the first to detect desaturation (change in SpO2 > 3%) in 4 of 8 subjects (p < 0.05), and the Nellcor N200 reflectance oximeter (Nellcor, Inc., Pleasanton, CA) was first in 3 of 8 subjects (p < 0.05). During resaturation (after administering 100% oxygen), the Novametrix Oxypleth (Novametrix, Wallingford, CT) was significantly faster than other oximeters (p < 0.05) to return to baseline (SpO2 = 98%).
  
  
  CONCLUSIONS
  Most models of oximeters tested performed well when hemoglobin oxygen saturation was high, but all were inaccurate when SaO2 was approximately 75%. During induced hypoxemia, there were significant differences in the response times of oximeters tested, with no model demonstrably superior to others in all measures of performance.
authors.affiliation: Department of Anesthesiology, University of California at Irvine, Orange 92668, USA.
authors.forename: N S
authors.initials: NS
authors.lastname: Trivedi
authors.forename: A F
authors.initials: AF
authors.lastname: Ghouri
authors.forename: E
authors.initials: E
authors.lastname: Lai
authors.forename: N K
authors.initials: NK
authors.lastname: Shah
authors.forename: S J
authors.initials: SJ
authors.lastname: Barker
mesh_terms: D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation*; D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D008297:Male; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies
chemical_list: D010100:Oxygen