Nellcor OxiMax N 5500 Service Manual page 95

System Processing Description
MAP
Distole
Systole
Systole
MAP
Distole
Overall Accuracy Discussion
Overall system accuracy shall be determined by considering various influences of the
pressure sensor accuracy, motion artifacts, other artifact created by pressure valve,
technical errors of electrical components, and the origin error of oscillometric method.
The origin error of oscillometric comes from the basic theory of that the MAP is
determined by the pulse. Therefore, there might be an error of the time between two
pulses. In another words, the greatest amplitude point of pulses could not represent the
MAP point exactly.
On clinical trial perspective, overall system accuracy is not easy to be determined. The
clinical trial test protocols have been tried and have been described in many treatises,
and international standards. So, there are many methods to determine the overall system
accuracy of Automated Sphygmomanometer using the oscillometric method. But, there
are no absolute test protocols to determine the overall system accuracy of the
Automated Sphygmomanometer using oscillometric method. Normally, the Gold
standards of Blood pressure for the reference are the intra-arterial pressure and the
auscultatory method.
The popular standard for the overall system accuracy is AAMI, SP -10 1992; 1996
(Electronic or automated sphygmomanometers).
The main test conditions are as follow:
A. Data comparing the Intra-arterial or the auscultatory by the clinical experts with the
automated sphygmomanometer.
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TIME
TIME
N5500 Service Manual
Oscillometric Response
(Pressure Pulses)
Cuff Pressure