On Better Estimating and Normalizing the Relationship between Clinical Parameters: Comparing Respiratory Modulations in the Photoplethysmogram and Blood Pressure Signal (DPOP versus PPV)

Figure 4

Distribution of gradient-associated errors in DPOP. A five-point smoothing distribution is overlaid on the histograms to aid interpretation. (a) Theoretical distribution using simple model with amplitude modulations ranging from 0 to and a gradient error from to . These are arbitrarily chosen ranges and other ranges lead to a similar positively skewed distribution of the error. (b) Actual distribution or errors from the LMSO method. Note that these will also include errors from other sources including random signal noise, although a positive skew is obvious in the data.

(a)

(b)