GE HEALTHCARE B20, User'S Reference Manual

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B40/B20 Patient Monitor
14-12
The operating cycle is composed of four parts: inflation time, deflation time, evaluation time,
and wait time. Wait time, which varies from mode to mode, is affected by the cycle time (auto
mode) or operator intervention (manual mode). The figure shows the basic operating cycle for
an NIBP determination.
Figure 14-5 NIBP - Auto Mode
Systolic Search
If systolic pressure is not found, the NIBP parameter can search at cuff pressures higher than
the initial target pressure. The parameter will inflate the cuff above the initial target pressure to
get better data in the systolic region. The maximum pressure allowed in systolic search is
limited by the normal range for cuff pressures.
In any operating mode, if a patient's systolic pressure exceeds the inflation pressure, the
parameter will begin normal deflation sequence, detect the absence of a systolic value, stop
deflation, reinflate to a higher (than initial) inflation pressure (290 mmHg maximum in adult
mode; 145 mmHg in neonatal mode), and resume the normal deflation sequence.
If it has been 16 minutes or less since the last determination and the current blood pressure is
similar to the previous reading, the monitor will try to make an accelerated determination of
blood pressure. During irregular rhythms, only pulses from the current determination are used
in calculating the blood pressure values. In order to ensure adequate artifact rejection
capability and optimal SuperSTAT NIBP performance, several criteria used to match and qualify
the oscillometric pulses at each pressure step are relaxed while supplementing the criteria with
additional information from ECG.
NOTE: (Adult/Pediatric only) When ECG is monitored, SuperSTAT NIBP is able to
determine blood pressure in the presence of irregular heart rhythms. At the beginning
of a SuperSTAT NIBP determination, the coefficient of variation from the previous 120
ECG R-R intervals is used to determine if an irregular rhythm is present.
Accuracy of the NIBP parameter was validated against the intra-arterial method. Do not use
the auscultatory method to verify the accuracy of the NIBP parameter. Auscultatory method
(using cuff and stethoscope) calculates the mean pressure value from audible sounds at
systolic and diastolic, but the NIBP parameter method detects all three values.