Specifications

73
Principles of Noninvasive Blood Pressure
Determination
The oscillometric method of determining BP is
accomplished by a sensitive transducer which measures cuff
pressure and minute pressure oscillations within the cuff.
The first determination sequence initially pumps up to a cuff
pressure of about 180 mmHg for adult/pediatric patients, or
110 mmHg for neonates depending on the initial target
pressure preset. After inflating the cuff, the Monitor begins
to deflate it and measures systolic pressure, mean pressure,
and diastolic pressure. When the diastolic pressure has been
determined, the Monitor finishes deflating the cuff and
updates the systolic, diastolic, and MAP displays on the
front panel.
The Monitor deflates the cuff one step each time it detects
two pulsations of relatively equal amplitude. The time
between deflation steps depends on the frequency of these
matched pulses (pulse rate of the patient). However, if the
Monitor is unable to find any pulse within several seconds,
it will deflate to the next step. The process of finding two
matched pulses at each step provides artifact rejection due
to patient movement and greatly enhances the accuracy of
the Monitor. The figure shows the BP determination
sequence.
OSCILLATION
AMPLITUDE
CUFF PRESSURE
170
162
154
146
138
130
122
114
106
98
90
82
74
66
58
SYSTOLIC
MAP
DIASTOLIC
TIME
BP Determination Sequence
Appendix C
COMPACT MAN-REV B 1/12/99, 9:47 AM73