Spacelabs Healthcare 98000, Operation Manual

Page: 87 / 122

070-2567-03 Rev. A
15-9
Each epoch’s sequence of PSD values is a different color to distinguish one from another. By
default, the system shows each epoch as a colored 3-D line graph. This may be changed to a 3-D
bar graph using the buttons provided on the toolbar.
15.12.1 To use the Frequency 3D screen:
1. In the window pane view on the left, click Frequency 3D.
2. If you wish to change the maximum PSD, locate the Max PSD box, click the down arrow,
and select another value.
3. To rotate the 3-D graph clockwise, click Rotate right.
4. To rotate the 3-D graph counter-clockwise, click Rotate left.
5. To scroll the 3D graph up / down / left / right, click the appropriate red arrow button.
Note that scrolling left / right refers to the frequency values shown, regardless of how the
graph is currently rotated.
6. To zoom the 3D graph in or out, either horizontally or vertically, click the appropriate
zoom button. Note that zooming horizontally refers to the frequency values shown,
regardless of how the graph is currently rotated.
7. To change the format of how the epoch PSD values are drawn, click either Line or Bar as
appropriate.
15.13 HRV Terms and calculations
NN 50
This is the count of successive normal-to-normal intervals differing by more than x milliseconds,
where x is the threshold value entered in the Time Parameters screen (default 50). Calculation is
based on qualified intervals only. % NN 50. This is the NN 50 value expressed as a percentage of
the total number of qualified beats.
Day / Night Epochs
The Day and Night epochs are specified by these periods. Both of these epochs are analyzed
separately and in isolation from the full recording.
Day / Night Deltas
After calculation of each discrete Day / Night epoch value, these represent the difference
between corresponding results for the two epochs.
15.14 Heart Rate Calculation
Pathfinder SL calculates heart rate as follows.
For each beat
The heart rate is calculated using a sliding average of the intervals of the previous 3 beats.
For each period
The heart rate for the period is calculated by summing the intervals for all valid beats within the
period and then dividing by the number of valid beats in the period to get the average HR.