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Chapter 10: NIBP Monitoring
User Manual
10.1 GENERAL
NIBP (Non-invasive Blood Pressure) measurement is based on the oscillometric technique.
Initially, cuff is inflated to a pressure greater than systolic pressure as blood flow in the extremity
occludes effectively. Then the pressure in the cuff is gradually reduced until the patient pressure
is detected and the cuff is deflated completely.
Systolic, Diastolic and Mean Arterial pressures can be calculated using pressure pulses detected
during pressure drop. Oscillation amplitude increases to a maximum peak and then decreases. If
the process of the cuff pressure reduction is done appropriately and pulses detected between
systolic and diastolic pressures are collected, the profile curve can be obtained using pulses'
pressure and amplitude. The peak oscillation amplitude is defined as the Mean Arterial Pressure
(MAP). Systolic and diastolic pressures can be obtained from suitable thresholds before and after
MAP pressure.
These thresholds are based on a data set containing a large number of measurements that are
obtained in comparison with the IBP pressure. It should be noted that in patients with high
pressure, the systolic and diastolic values may have lower accuracy than those with normal
pressure. This restriction is not specific to the SAADAT monitor and includes all monitors that
use an oscillometric method to measure NIBP.
Changes in cuff pressure during measurement
10-2
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