Portable blood pressure measurements: performance of Korotkov sound analysis techniques

Noninvasive portable blood pressure systems (PBPS) are typically based on korotkov sound technique. The performance of related Korotkov sound analysis techniques was assessed in PBPS data obtained from nine normotensive and nine hypertensive men. Multiple-seated PBPS measurements were taken, each following 1 minute of quiet rest, moderate walking, and stair climbing; each PBPS measurement was accompanied by a simultaneous auscultatory measurement in the same arm. In subsequent manual PBPS data analysis, PBPS systolic and diastolic BPs were within 4 mm Hg of corresponding auscultatory BPs 86% and 88% of the time; BPs following rest and walking showed greater accuracy, while those following stair climbing were less accurate. Interestingly, automated analysis of diastolic PBPS data (using selective bandpass filtering, amplitude normalization, and comparator decision ratios) provided a level of accuracy similar to that obtained from manual data analysis. Overall, both manual and automated Korotkov sound analysis techniques can provide BP results that agree quite well with auscultatory determinations.