Standing position increased carotid-femoral pulse wave velocity compared to supine (7.3 vs 5.2 m/s, p<0.001), enabling the measurement of an individualized blood pressure calibration index.
Observational (n=27)
Does measuring blood pressure and carotid-femoral pulse wave velocity in supine and standing positions provide a reliable subject-specific calibration index for blood pressure estimation?
Measuring blood pressure and carotid-femoral pulse wave velocity in supine and standing positions provides a simple, individualized calibration index for continuous blood pressure monitoring.
Absolute Event Rate: 7.3% vs 5.2%
p-value: p=<0.001
Devices that estimate blood pressure from arterial pulse wave velocity (PWV) potentially provide continuous, ambulatory blood pressure monitoring. Accurate blood pressure estimation requires reliable quantification of the relationship between blood pressure and PWV. Regression to population normal values or, when using limb artery PWV, changing hydrostatic blood pressure within the limb provides a calibration index. Population lookup tables require accurate anthropometric correlates, assuming no individual variation. Only devices that measure PWV in the limb can use limb position changes. This study proposes a method for developing a calibration curve independent of lookup tables and useful for large artery PWV measurement, such as carotid-femoral PWV (PWVcf). PWVcf was measured in 27 normal subjects (15 female, 36±19 years) in both the supine and standing position. The change in systemic pressure was measured and hydrostatic pressure change calculated from estimated vessel path length height, measured using body surface distances. Brachial diastolic blood pressure increased for all subjects from supine to standing (supine 70±8 mmHg, standing 83±8 mmHg, p<;0.001) with an additional hydrostatic change across the carotid-femoral path length of 19±2 mmHg (p<;0.001). PWVcf also increased in all subjects (supine 5.2±1.3 m/s, standing 7.3±2.2 m/s, p<;0.001). The subject-specific calibration index (ΔDP/ΔPWVcf) varied amongst the cohort (20±8 mmHg/m/s), was correlated with age (-0.57, p=0.002) and seated aortic systolic pressure (-0.38, p=0.048) and was always greater than zero. Thus, this study describes a simple but novel method of measuring an individualized calibration index using blood pressure and PWV measurements in the supine and standing position.
Butlin et al. (Sat,) conducted a observational in Healthy subjects (n=27). Standing position vs. Supine position was evaluated on Carotid-femoral pulse wave velocity (PWVcf) (p=<0.001). Standing position increased carotid-femoral pulse wave velocity compared to supine (7.3 vs 5.2 m/s, p<0.001), enabling the measurement of an individualized blood pressure calibration index.