Blood pressure monitoring apparatus

#1. Field of Invention

#The present invention relates to a blood pressure monitoring apparatus used in the fields where the continuous blood monitoring for the patient is required in the operation room, the intensive care unit, the emergency treatment room, or the artificial dialysis treatment room.

#2. Related Art

#FIG. 1 is a block diagram of the schematic system configuration showing one example of a blood pressure monitoring apparatus according to the present invention.

#FIG. 2 is a flowchart showing the operation of the blood pressure monitoring apparatus according to the invention.

#FIG. 3 is a waveform chart for explaining the pulse wave propagation time for measurement in the blood pressure monitoring apparatus according to the invention.

#A fundamental idea of this invention is as follows.

#One method for the blood pressure monitoring apparatus for making the noninvasive blood pressure measurement involves measuring the blood pressure using the pulse wave propagation velocity (pulse wave propagation time for fixed distance). A principal for measuring the blood pressure from this pulse wave propagation velocity is as follows. That is, a specific point of pulse wave appears at later time than the specific point of aorta wave in the peripheral blood vessel side for the fingers or ears for example, as shown in FIG. 3. This delay time is the pulse wave propagation time. And the pulse wave propagation velocity corresponding to the pulse wave propagation time for fixed distance is represented as a function of the volumetric elasticity of blood vessel, and if the blood pressure increases, the volumetric elasticity of blood vessel increases, the blood vessel wall is hardened, and the propagation velocity becomes fast.

#Accordingly, the fluctuation of blood pressure can be obtained from the pulse wave propagation velocity. And the fluctuation of blood pressure of the subject can be monitored by measuring the pulse wave propagation time successively. In this case, the amount of change ΔT in pulse wave propagation time exceeds a predetermined change threshold ΔTs of pulse wave propagation time, it is judged that the subject has a sudden change in blood pressure, at which point the noninvasive blood pressure measurement with the cuff may be performed.