How Is Central Blood Pressure Measured - Microlife BP 3SZ1-1 Instruction Manual

Special functions

How is central blood pressure measured?

The device measures brachial systolic and diastolic blood
pressure as usual. However, where the cuff normally
totally deflates after the blood pressure measurement,
the cuff now stops deflating at approximately 60 mmHg
cuff pressure to keep a stable pressure on the brachial
artery for approximately 10 seconds which is needed to
acquire brachial pulse volume plethysmography (PVP)
waveforms (pulse volume recording). During these 10
seconds approximately 10 PVP waveforms are recorded
from which one average PVP waveform is determined
and analysed. From the average PVP waveform, some
characteristic points (parameters) are identified that
are directly related to arterial compliance (stiffness) and
wave reflections. With these parameters and previously
measured peripheral (regular) blood pressure the central
systolic blood pressure value and the central pulse
pressure value are then determined
The time that is needed to determine the central blood
pressure value may vary among patients; i.e. with faster
heart rate, less time is required for collecting the number
18
1 .
of required PVP waveforms. It is very important to keep
the arm still during the time the PVP waveforms are
collected.
Accuracy of the central blood pressure
parameters
The accuracy of central blood pressure parameters
performed with this device can only reliably
be determined against intra-arterial blood
pressure measurement. The device is a certified
equivalence with the WatchBP Office Central that has
been validated against simultaneous recorded intra-
arterial blood pressure measurement in 85 subjects
and showed high accuracy
1. Sung, S.H., et al., Measurement of central systolic blood pressure by
pulse volume plethysmography with a noninvasive blood pressure
monitor. Am J Hypertens, 2012. 25: 542-8.
Cheng, H.M., et al., Measurement accuracy of a stand-alone
2.
oscillometric central blood pressure monitor: a validation report for
Microlife WatchBP Office Central. Am J Hypertens, 2013. 26: 42-50.
2 .