title: How well can anaesthetists discriminate pulse oximeter tones?
abstract: The ability of experienced anaesthetists to discern oxygen saturation by listening to the tones of a Datex AS3 pulse oximeter was examined. Five-second samples were recorded using a high fidelity patient simulator and replayed singly and in pairs. Whilst the lower saturations were generally recognized as lower, the perceived range was greatly compressed. Median perceived estimates for 70% saturation was 89%, for 80% was 93% and for 94% was 94%. When comparing pairs of samples, the direction of the difference was correctly discerned by 70% of anaesthetists for differences of 2%, rising to 95% for differences of greater than 8% oxygen saturation. The magnitude of the difference was consistently underestimated. With an actual difference of 20%, the median estimate was 5%. The results indicate that while qualitative estimate changes in oxygen saturation are moderately reliable, quantitative estimation is severely limited by a compromised perceived scale. This may lead to underestimation of the severity if the auditory signal is relied on in isolation. A non-linear (musical) scale may prove more appropriate and should be investigated. Testing experienced anaesthetists demonstrated that most could detect the direction, but not the magnitude of a change in saturation by listening to the change in pitch of a Datex AS3 pulse oximeter tone.
authors.affiliation: Sydney Medical Simulation Centre, Royal North Shore Hospital and The University of Sydney, New South Wales.
authors.forename: R W
authors.initials: RW
authors.lastname: Morris
authors.forename: P J
authors.initials: PJ
authors.lastname: Mohacsi
mesh_terms: D000328:Adult; D000776:Anesthesiology; D005246:Feedback; D006801:Humans; D008875:Middle Aged; D010092:Oximetry / Q000295:instrumentation*; D010100:Oxygen / Q000097:blood; D010897:Pitch Discrimination / Q000502:physiology*; D013016:Sound
chemical_list: D010100:Oxygen