LAUSR

Background Fixed-ratio and slope-based algorithms are used to derive oscillometric blood pressure (BP). However, a paucity of published data exists assessing the accuracy of these methods. Our objective was to determine the accuracy of fixed-ratio and slope-based algorithms in healthy adults and in adults with cardiovascular risk factors. Patients and methods Overall, 85 healthy adults (age≥18 years) and 85 adults with cardiovascular risk factors were studied. Three oscillometric and four two-observer mercury-based auscultation measurements were performed in each, according to International Standards Organization 2013 methodology. Two fixed-ratio algorithms and one slope-based algorithm were applied to process oscillometric waveform envelopes and derive oscillometric BP. Paired and unpaired t-tests were used to compare mean oscillometric BP within and between each group, respectively. Results For healthy adults, mean age was 50.3±17.8 years, mean arm circumference was 30.4±3.8 cm, and 62% were female. In the cardiovascular risk group, mean age was 63.8±12.4 years, mean arm circumference was 31.9±4.2 cm, and 62% were female. For systolic BP, the fixed-ratio algorithms produced the lowest mean error and narrowest SD. For diastolic BP, mean errors were similar for all three algorithms, but the fixed-ratio algorithms had higher precision. The comparison of healthy adults and those with cardiovascular risk factor showed high variability for systolic and diastolic BP (SD: 8.113.9 mmHg). Conclusion In both healthy adults and in those with cardiovascular risk factors, the fixed-ratio technique performed better than the slope-based algorithm. High between-group variability indicates that subject-specific algorithms may be needed.