12-1 
12 Monitoring NIBP 
 
 
12.1 Introduction 
The patient monitor uses the oscillometric method for measuring the non-invasive blood 
pressure (NIBP). This measurement can be used for adults, pediatrics and neonates. 
 
Automatic non-invasive blood pressure monitoring uses the oscillometric method of 
measurement. To understand how this method works, we’ll compare it to the auscultative 
method. With auscultation, the clinician listens to the blood pressure and determines the 
systolic and diastolic pressures. The mean pressure can then be calculated with reference to 
these pressures as long as the arterial pressure curve is normal. 
 
Since the monitor cannot hear the blood pressure, it measures cuff pressure oscillation 
amplitudes. Oscillations are caused by blood pressure pulses against the cuff. The oscillation 
with the greatest amplitude is the mean pressure. This is the most accurate parameter 
measured by the oscillometric method. Once the mean pressure is determined, the systolic 
and diastolic pressures are calculated with reference to the mean. 
 
Simply stated, auscultation measures systolic and diastolic pressures and the mean pressure is 
calculated. The oscillometric method measures the mean pressure and determines the systolic 
and diastolic pressures. 
 
As specified by IEC 60601-2-30, NIBP measurement can be performed during 
electro-surgery and discharge of defibrillator. 
 
NIBP diagnostic significance must be decided by the doctor who performs the measurement. 
 
NOTE
z  Blood pressure measurements determined with this device are equivalent to those 
obtained by a trained observer using the cuff/stethoscope auscultatory method or 
an intra-arterial blood pressure measurement device, within the limits prescribed 
by the American National Standard, Manual, electronic, or automated 
sphygmomanometers.