Hadeco Smartdop 30EX, Руководство по эксплуатации

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8. Technical Information
8-1. Principles
Model Smartdop 30EX is designed to obtain various blood flow velocity through the
ultrasound which is transmitted from probe to patient body and is reflected by the blood
(hemocyte, etc.).
The unit amplifies the high frequency oscillation output and then supplies it to the
transmitter transducer. It is converted to ultrasound by the transducer and the ultrasound is
transmitted to external objects. The ultrasound moves straight through biophysical object,
and is reflected by the moving object (blood flow, fetal heartbeat etc.).
The reflected ultrasound is received by the receiving transducer and is converted into
electric signals again.
The converted signals are amplified and then detected. After removing unnecessary noise
from the signals and improving S / N ratio at the filter circuit, the Doppler shift signals are
amplified and are converted to audible sounds through a speaker or a headset.
Simultaneously, the Doppler shift signals are applied to the CPU and converted to blood
flow velocity waveform signals which can be displayed and printed.
On the ARM / LEG and TOE pressure modes, the blood pressure cuff is wrapped where
the blood pressure is taken and the probe is put on the lower extremity artery by the
operator.
Before the inflation, the peak amplitudes of the blood flow signals should be stable. As the
cuff pressure goes up by activating the inflation pump, the blood vessel is being pressed
and the peak amplitudes become lower. The CPU finds the point where the peak
amplitudes are below the threshold and waits until the cuff pressure is inflated an
estimated 30 mmHg above the point. Then the CPU deactivates the inflation pump and
lets the cuff pressure go down at a moderate rate until the first blood flow signal that
exceeds the threshold is detected.
The cuff pressure at the first signal is the systolic pressure. After confirming a return of the
rhythmical blood flow signals, the CPU opens the air valve to dump the cuff pressure and
displays the systolic blood pressure on the LCD.