title: A comparison of linear and logarithmic auditory tones in pulse oximeters.
abstract: This study compared the ability of forty anaesthetists to judge absolute levels of oxygen saturation, direction of change, and size of change in saturation using auditory pitch and pitch difference in two laboratory-based studies that compared a linear pitch scale with a logarithmic scale. In the former the differences in saturation become perceptually closer as the oxygenation level becomes higher whereas in the latter the pitch differences are perceptually equivalent across the whole range of values. The results show that anaesthetist participants produce significantly more accurate judgements of both absolute oxygenation values and size of oxygenation level difference when a logarithmic, rather than a linear, scale is used. The line of best fit for the logarithmic function was also closer to x = y than for the linear function. The results of these studies can inform the development and standardisation of pulse oximetry tones in order to improve patient safety.
authors.affiliation: Department of Pediatric Anesthesia, BC Children's Hospital, Vancouver, BC, Canada; Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Zoe
authors.initials: Z
authors.lastname: Brown
authors.affiliation: Cognition Institute, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK. Electronic address: jedworthy@plymouth.ac.uk.
authors.forename: Judy
authors.initials: J
authors.lastname: Edworthy
authors.affiliation: Plymouth University Penninsula School of Medicine and Dentistry, The John Bull Building, Plymouth Science Park, Plymouth, Devon PL6 8BU, UK.
authors.forename: J Robert
authors.initials: JR
authors.lastname: Sneyd
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Centre, Nashville, TN, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Schlesinger
mesh_terms: D000465:Algorithms; D000776:Anesthesiology; D006801:Humans; D016014:Linear Models; D010092:Oximetry / Q000706:statistics & numerical data*; D010100:Oxygen / Q000097:blood; D010897:Pitch Discrimination; D013016:Sound
chemical_list: D010100:Oxygen
keywords: Auditory perception; Patient monitoring; Patient safety; Pulse oximetry