Abstract
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 language | English |
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Pages (from-to) | 3593-3601 |
Number of pages | 9 |
Journal | IEEE Transactions on Biomedical Engineering |
Volume | 68 |
Issue number | 12 |
Early online date | 12 May 2021 |
DOIs | |
Publication status | Published - Dec 2021 |
Keywords
- 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