24
Human NIBP Nano
Owner’s Guide
during an AutoCal, the last valid value is extrapolated during this
period.
•
Heart rate:
The heart rate is calculated from the number of 5 ms
sample intervals, N, in a beat (the sampling rate is 200 Hz). Hence,
heart rate = (60 × 200/N) beats per minute (bpm).
•
Interbeat interval:
This is the period between two successive
upstrokes in the Finger Pressure channel, in 5 ms resolution.
This puts certain constraints on the resolution of the interval,
particularly at short intervals. Note: If the pressure wave is not
available, such as when an AutoCal is performed, detection is
switched to the plethysmographic pulse wave. Hence, heart rate
and interbeat interval are available during an AutoCal. However,
during finger cuff switching, no sensible data is recorded and a
zero value is returned. The calculated data (Systolic, Mean Arterial,
Diastolic, Heart Rate and Interbeat Interval) is advanced by one
interbeat interval value and a second to correctly align with the
Finger Pressure signal.
Figure 2–11
The Human NIBP
LabChart settings fi le
showing the 11 channels
recorded from the Human
NIBP Nano Interface.