Omron HBP-1100 - Инструкция по эксплуатации - Страница 24

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Non-Invasive Pressure Measurement Principles

Oscillometric method

The beat in the pulsation generated by the contraction of the heart is captured 

as the pressure inside the cuff to measure the blood pressure. If the cuff 

wrapped  around  the  upper  arm  is  pressurized  suf ficiently,  the  blood  flow 

stops, but the beat of the pulsation is present and the pressure inside the cuff 

receives this and oscillates. Next, as the pressure inside the cuff gradually 

decreases, the oscillation of the pressure within the cuff gradually increases 

and reaches a peak. As the pressure within the cuff decreases further, the 

oscillation decreases from its peak.

The pressure within the cuf f and the relationship with the increase and 

decrease of the oscillation within the cuf f in this series of processes are 

stored into memor y, calculations are carried out, and the blood pressure 

value is determined.

The pressure within the cuf f when the oscillation increases drastically is 

the systolic pressure and the pressure within the cuf f when the oscillation 

decreases drastically is the diastolic pressure. Also, the pressure within the cuff 

when the oscillation peaks is taken as the average pulsation pressure.

The oscillometric method does not determine the blood pressure value 

instantly like a microphone type automatic blood pressure gauge with the 

auscultation method, but rather determines it from the series of change 

curves as explained above. Therefore, it is not easily affected by external 

noise, an electric scalpel or other electro surgical instruments.

KOROTKOV SOUNDS

RADIAL PULSE

5 SEC

OSCILLATIONS IN CUFF PRESSURE

CUFF 

PRESSURE

Comparison between the auscultatory, oscillometric and 

palpatory methods of measuring blood pressure.

L.A. Geddes,

“The Direct and Indirect Measurement of Blood Pressure”, Year Book Medical Publishers, Inc. 1970