title: Impact of Oxygenation Status on the Noninvasive Measurement of Hemoglobin.
abstract: Noninvasive monitoring of hemoglobin (SpHgb) via pulse oximetry has the potential to alert caregivers to blood loss. Previous studies have demonstrated that changes in oxygenation may impact accuracy.
  
  
  
  Twenty normal volunteers were monitored using SpHgb at sea level, during ascent to 14,000 feet, at 14,000 feet with 100% oxygen delivery, and again at sea level. Each period consisted of 15 minutes of monitoring. SpHgb measurements were compared to a blood sample using Bland Altman analysis. The loss of the SpHgb signal was also recorded.
  
  
  
  The mean difference in measured hemoglobin (Hgb) between a venous sample and SpHgb was -2.6 ± 0.96 at 14,000 feet. Ascent to 14,000 feet resulted in a predictable fall in SpO2and was associated with loss of the SpHgb signal for half the period of observation (7.4 minutes). In the other three conditions, SpHgb signal was missing 1 to 12.6% of the time. The nadir SpO2 was not predictive of the loss of SpHgb signal.
  
  
  
  Changes in oxygenation in normal volunteers are associated with short-term SpHgb signal loss (<10 minutes), but no impact on the measured SpHgb.
authors.affiliation: Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267.
authors.forename: Dina
authors.initials: D
authors.lastname: Gomaa
authors.affiliation: Aeromedical Research Branch, USAFSAM, 2510 Fifth Street Building 840, Wright-Patterson AFB, OH 45433-7901.
authors.forename: Dario
authors.initials: D
authors.lastname: Rodriquez
authors.affiliation: Center of Sustainment and Trauma Readiness Skills, 234 Goodman Street, Cincinnati, OH 45229.
authors.forename: Michael
authors.initials: M
authors.lastname: Petro
authors.affiliation: Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Blakeman
authors.affiliation: Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Branson
mesh_terms: D000328:Adult; D000531:Altitude; D005260:Female; D006454:Hemoglobins / Q000502:physiology*; D006470:Hemorrhage / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008991:Monitoring, Physiologic / Q000592:standards*; D010102:Oxygen Inhalation Therapy / Q000379:methods
chemical_list: D006454:Hemoglobins