Systolic peak foot-to-apex time interval, a novel oscillometric technique for systolic blood pressure measurement

Abstract

Background:Noninvasive blood pressure (BP) measurement is essential for the study of human physiology but automatic oscillometric devices only estimate SBP and DBP using various, undisclosed algorithms, precluding standardization and interchangeability. We propose a novel approach by tracking, during pneumatic cuff deflation, the time interval from the foot to the apex of the systolic peak of the oscillometric signal, which reaches a maximum concomitant with the first Korotkoff sound.Method:In 145 study participants and patients (group 1), we measured the systolic brachial artery blood pressure by Korotkoff sound recording, conventional oscillometry, and our fully automated systolic peak foot-to-apex time interval (SFATI) technique. In 35 other patients (group 2), we compared SFATI with intra-arterial measurement.Results:In group 1, the concordance correlation coefficient was 0.989 and 0.984 between SFATI and Korotkoff sounds, 0.884 and 0.917 between oscillometry and Korotkoff sounds, and 0.882 and 0.919 between SFATI and oscillometry, respectively, on the left and right arm. In group 2, it was 0.72 between SFATI and intra-arterial measurement, 0.67 between oscillometry and intra-arterial measurement, and 0.92 between SFATI and Korotkoff sounds. In 40 study participants, the reproducibility study yielded a concordance coefficient of 0.95 for SFATI and 0.94 for Korotkoff sounds.Conclusion:SFATI BP measurement shows an excellent concordance with the auscultatory technique, offering a major improvement over current oscillometric techniques and allowing standardization.

Direct Determination rather than Oscillometric Estimation of Systolic Blood Pressure in Patients with Severe Chronic Kidney Disease

“…Our study illustrates this issue by revealing frequent, large measurement errors with oscillometry and confirms that SFATI is more accurate [26], even though both techniques showed satisfactory reproducibility. Interestingly, the present study compares the SFATI technique to a nonvalidated but widely used oscillometric device (VS-800 Vital Signs Monitoring Module; Mindray) different from the one we used in our previous study [26] (Dinamap ProCare-300; GE Healthcare, Chicago, IL, USA), which had been duly validated but showed similar discrepancies with the Korotkoff sounds. This suggests that the measurement bias (about 6 mm Hg in the present study) is related to the oscillometry technique itself rather than to a specific device and is not just a reproducibility issue.…”

“…The standardization of NIBP devices is still an unattained goal and, even with duly validated devices [30], BP measurement may prove unreliable or erroneous in certain clinical settings [31]. Our study illustrates this issue by revealing frequent, large measurement errors with oscillometry and confirms that SFATI is more accurate [26], even though both techniques showed satisfactory reproducibility. Interestingly, the present study compares the SFATI technique to a nonvalidated but widely used oscillometric device (VS-800 Vital Signs Monitoring Module; Mindray) different from the one we used in our previous study [26] (Dinamap ProCare-300; GE Healthcare, Chicago, IL, USA), which had been duly validated but showed similar discrepancies with the Korotkoff sounds.…”

“…The Korotkoff sound-based systolic (SBPk) and diastolic BPs were automatically detected by the software on the signals recorded as the cuff pressure at which the amplitude of Korotkoff sounds became, respectively, higher and then lower than the predetermined threshold of 5% of its maximum value. The recorded cuff pressure signal was independently processed with the SFATI algorithm implemented as a MATLAB R2019b routine (MathWorks, Natick, MA, USA) to determine SBPs [26].…”

“…The systolic peak foot-to-apex time interval (SFATI) is a new technique which provides consistently improved concordance with Korotkoff sounds in the measurement of SBP [26]. Unlike oscillometry, which relies on the amplitude of the oscillations of pneumatic-cuff pressure during deflation, the SFATI algorithm tracks the time interval from the onset to the apex of the systolic peak of these oscillations.…”

Dempster–Shafer Fusion Based on a Deep Boltzmann Machine for Blood Pressure Estimation

“…The algorithm of maximum amplitude (MAA) is predominantly utilized to estimate the BP mean by monitoring the cuff pressure in the maximum oscillation. However, the MAA using a fixed ratio is insufficient for estimating the BP since the proportion of these fixed characteristics significantly varies according to the rhythm of the heart, movement artifacts, and cuff size [1,2], which leads to uncertainties of the BP in practice in the oscillometric BP measurements [3][4][5]. Physiological characteristics have a significant impact on these ratios.…”