title: Feasibility and accuracy of nasal alar pulse oximetry.
abstract: BACKGROUND
  The nasal ala is an attractive site for pulse oximetry because of perfusion by branches of the external and internal carotid arteries. We evaluated the accuracy of a novel pulse oximetry sensor custom designed for the nasal ala.
  
  
  METHODS
  After IRB approval, healthy non-smoking subjects [n=12; aged 28 (23-41) yr; 6M/6F] breathed hypoxic mixtures of fresh gas by a facemask to achieve oxyhaemoglobin saturations of 70-100% measured by traditional co-oximetry from radial artery samples. Concurrent alar and finger pulse oximetry values were measured using probes designed for these sites. Data were analysed using the Bland-Altman method for multiple observations per subject.
  
  
  RESULTS
  Bias, precision, and accuracy root mean square error (ARMS) over a range of 70-100% were significantly better for the alar probe compared with a standard finger probe. The mean bias for the alar and finger probes was 0.73% and 1.90% (P<0.001), respectively, with corresponding precision values of 1.65 and 1.83 (P=0.015) and ARMS values of 1.78% and 2.72% (P=0.047). The coefficients of determination were 0.96 and 0.96 for the alar and finger probes, respectively. The within/between-subject variation for the alar and finger probes were 1.14/1.57% and 1.87/1.47%, respectively. The limits of agreement were 3.96/-2.50% and 5.48/-1.68% for the alar and finger probes, respectively.
  
  
  CONCLUSIONS
  Nasal alar pulse oximetry is feasible and demonstrates accurate pulse oximetry values over a range of 70-100%. The alar probe demonstrated greater accuracy compared with a conventional finger pulse oximeter.
authors.affiliation: Department of Anesthesiology, University of Florida, PO 100254, 1600 SW Archer Road, Gainesville, FL 32601-0254, USA morey@ufl.edu.
authors.forename: T E
authors.initials: TE
authors.lastname: Morey
authors.affiliation: Department of Anesthesiology, University of Florida, PO 100254, 1600 SW Archer Road, Gainesville, FL 32601-0254, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rice
authors.affiliation: Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S. Maryland Ave., MC 3077, CNPRU, Room L-603, Chicago, IL 60637, USA.
authors.forename: T
authors.initials: T
authors.lastname: Vasilopoulos
authors.affiliation: Department of Anesthesiology, University of Florida, PO 100254, 1600 SW Archer Road, Gainesville, FL 32601-0254, USA Xhale, Inc., 3630 SW 47th Ave., Suite 100, Gainesville, FL 32608, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Dennis
authors.affiliation: Department of Anesthesiology, University of Florida, PO 100254, 1600 SW Archer Road, Gainesville, FL 32601-0254, USA Xhale, Inc., 3630 SW 47th Ave., Suite 100, Gainesville, FL 32608, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Melker
mesh_terms: D000328:Adult; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D055171:Nasal Cartilages / Q000098:blood supply*; D010092:Oximetry / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D055815:Young Adult
keywords: alar nasal cartilages; lateral nasal cartilages; nasal cartilages; oximetry; pulse oximetry