A&D TM-2440, Инструкция по эксплуатации

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11.
Appendix
11.1.
Principle of Blood Pressure Measurement
Measurement procedure : Wrap the cuff around the upper arm.
Inflate the cuff to a pressure exceeding the systolic blood pressure.
Then, exhaust the air from the cuff gradually. While the pressure is
detected in the cuff in the air exhaustion stage, the pulse waveform
appears in synchronization with the heartbeat. The pulse waveform
suddenly increases near the systolic blood pressure. It increases
further with exhaustion until it reaches the highest in amplitude, then
decreases gradually. The changes in the pulse waveform are
illustrated at next page. In the oscillometric blood pressure
measurement, the systolic blood pressure is specified as the point
where the amplitude increases suddenly after the pulse in the cuff
pressure is detected, the mean blood pressure is specified as the
point where the amplitude reaches the highest, the diastolic blood
pressure is specified as the point where the amplitude decreases
gradually and becomes small. Actually, the pressure sensor detects
the subtle changes in the cuff pressure with time, stores the pulse
waveform in memory, and evaluates the systolic and diastolic blood
pressures according to the oscillometric measurement algorithm.
The details in the algorithm vary with the blood pressure monitor.
Blood pressure values of adults and infants are measured by the
oscillometric method and are compared with those measured by the
auscultatory method. Diastolic blood pressure is defined to be the
end point of phase
4
in the auscultatory method. The pulse
waveform of the cuff pressure depends on the characteristics of the
cuff material. Therefore, by using the specified cuff and the
measurement algorithm, the measurement accuracy is maintained.
Air hose length is within
3.5
m because of the damping
characteristics due to pulse wave propagation.