Are Korotkoff sounds reliable markers for accurate estimation of systolic and diastolic pressure using brachial cuff sphygmomanometry

Branko G. Celler, Mark Butlin, Ahmadreza Argha, Isabella Tan, Andy Yong, Alberto Avolio

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)


    It is well known that non-invasive blood pressure measurements significantly underestimate true systolic blood pressure (SBP), and overestimate diastolic blood pressure (DBP). The aetiology for these errors has not yet been fully established. This study aimed to investigate the accuracy of Korotkoff sounds for detection of SBP and DBP points as used in brachial cuff sphygmomanometry. Brachial cuff pressure and Korotkoff sounds were obtained in 11 patients (6 males: 69.0 ± 6.2 years, 5 females: 71.8 ± 5.5 years) undergoing diagnostic coronary angiography. K2 Korotkoff sounds were obtained by high-pass filtering (>20 Hz) the microphone-recorded signal to eliminate low frequency components. Analysis of the timing of K2 Korotkoff sounds relative to cuff pressure and intra-arterial pressure shows that the onset of K2 Korotkoff sounds reliably detect the start of blood flow under the brachial cuff and their termination, marks the cuff pressure closely coincident with DBP. We have made the critical observation that blood flow under the cuff does not begin when cuff pressure falls just below SBP as is conventionally assumed, and that the delay in the opening of the artery following occlusion, and the consequent delay in the generation of K2 Korotkoff sounds, may lead to significant errors in the determination of SBP of up to 24 mmHg. Our data suggest a potential role of arterial stiffness as a major component of the errors recorded, with underestimation of SBP much more significant for subjects with stiff arteries than for subjects with more compliant arteries.

    Original languageEnglish
    Pages (from-to)3593-3601
    Number of pages9
    JournalIEEE Transactions on Biomedical Engineering
    Issue number12
    Early online date12 May 2021
    Publication statusPublished - Dec 2021


    • Arteries
    • Biomedical monitoring
    • Blood
    • Blood pressure
    • Brachytherapy
    • invasive and noninvasive blood pressure measurement
    • Korotkoff sounds
    • Measurement uncertainty
    • non-invasive blood pressure monitoring devices
    • Pressure measurement
    • systolic and diastolic blood pressure estimation


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