Photoplethysmographic signal aids indirect blood-pressure measurement

In the daily routine blood-pressure is measured non-invasively. The presently used methods are not reliable, the precision (reproducibility) of instruments applying these methods is modest. The photoplethysmographic (PPG) signal recorded simultaneously with the cuff pressure helps eliminate erroneous results during indirect blood pressure measurement. The PPG signal can also be used to estimate the change in blood-pressure without applying a cuff. The time delay between the ECG R peak and the leading edge of the PPG signal is influenced also by the arterial blood-pressure. This method might be useful in applications when the tracking of changes in - and not the absolute value of - blood-pressure is important, e.g. in intensive care monitoring.