Product Manual

2036991-001C CARESCAPE V100 Vital Signs Monitor D-5
Principles of Noninvasive Blood Pressure Determination: DINAMAP Classic and Auscultatory Reference Algorithm
DINAMAP Classic and Auscultatory Reference Algorithm
The oscillometric method of determining NIBP 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 160 mmHg for adult/pediatric patients or 110 mmHg for
neonates depending on initial target pressure preset. After inflating the cuff, the
monitor begins to deflate it and measures systolic pressure, mean arterial
pressure, and diastolic pressure. When the diastolic pressure has been
determined, the monitor finishes deflating the cuff and updates the screen.
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 NIBP determination sequence.
NIBP determination sequence
At each step the microprocessor stores cuff pressure, the matched pulse
amplitude, and the time between successive pulses. The stepped deflation and
matched pulse detection continues until diastolic pressure is determined or total
cuff pressure falls below 7 mmHg. The monitor then deflates the cuff (to zero
detected pressure), analyzes the stored data, and updates the screen.