title: High-fidelity digital recording and playback sphygmomanometry system: device description and proof of concept.
abstract: OBJECTIVE
  This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study.
  
  
  METHODS
  A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated.
  
  
  RESULTS
  The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP).
  
  
  CONCLUSIONS
  The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.
authors.affiliation: aDepartment of Biomedical Engineering, Hanyang University, Seoul bDepartment of Biomedical Engineering, University of Ulsan, Ulsan, Korea cHypertension Center, STRIDE-7, Third University Department of Medicine, Sotiria Hospital, Athens, Greece dMedaval Ltd eConway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
authors.forename: Jongshill
authors.initials: J
authors.lastname: Lee
authors.forename: Youngjoon
authors.initials: Y
authors.lastname: Chee
authors.forename: Inyoung
authors.initials: I
authors.lastname: Kim
authors.forename: Nikos
authors.initials: N
authors.lastname: Karpettas
authors.forename: Anastasios
authors.initials: A
authors.lastname: Kollias
authors.forename: Neil
authors.initials: N
authors.lastname: Atkins
authors.forename: George S
authors.initials: GS
authors.lastname: Stergiou
authors.forename: Eoin
authors.initials: E
authors.lastname: O'Brien
mesh_terms: D000465:Algorithms; D000703:Analog-Digital Conversion; D001795:Blood Pressure Determination / Q000295:instrumentation*; D003971:Diastole; D004581:Electronics; D004867:Equipment Design; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D015588:Observer Variation; D009991:Oscillometry / Q000295:instrumentation; D010865:Pilot Projects; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D019722:Sphygmomanometers; D018709:Statistics, Nonparametric; D019023:Stethoscopes; D013599:Systole; D014741:Video Recording / Q000295:instrumentation