JPH0143048Y2 - - Google Patents

Description

[Detailed description of the invention] This invention measures and maintains the maximum and diastolic blood pressure each time the cuff wrapped around the arm is automatically increased or decreased with a pump intermittently, and each numerical value is maintained until the next increase or decrease process. The present invention relates to a non-invasive automatic blood pressure monitor.

With this type of automatic blood pressure monitor, a patient's blood pressure can be continuously monitored non-invasively at the bedside. However, since blood pressure monitoring using a remote monitoring device targets critically ill patients, conventional blood pressure monitors have only been used with invasive blood pressure monitors. The detected blood pressure waveform signal was monitored.
However, depending on the patient's condition or the type of disease, non-invasive measurement may be sufficient.

Therefore, an object of the present invention is to provide a non-invasive automatic blood pressure monitor of the type mentioned at the beginning, which enables remote monitoring of blood pressure measured non-invasively instead of blood pressure waveform signals measured by an invasive method. shall be.

Next, embodiments will be described based on the illustrated embodiments.

Reference numeral 1 denotes a measurement/numeric display unit as an example of a conventional non-invasive automatic blood pressure monitor, and a pump 3 that automatically increases and depressurizes a cuff 2 wrapped around the arm intermittently at predetermined intervals, and a Korotkoff blood pressure monitor. A timing signal generation circuit 4 detects the systolic and diastolic blood pressure points using a so-called oscillometric method based on sound microphone detection or pulse changes and generates respective signals, and a transducer detects cuff pressure as an analog signal. Yusa 5
, an A/D converter 6 that outputs the detection signal as, for example, a BCD signal, and a systolic blood pressure point signal a.
a buffer memory 7 that temporarily stores the output signal of the A/D converter 6 when the signal b occurs, and a display 8 that numerically displays the systolic blood pressure by latching and decoding the contents of the buffer memory 7 when the diastolic blood pressure point signal b occurs. , a display 9 that similarly latches and decodes the output signal of the A/D converter 6 to numerically display the diastolic blood pressure when the diastolic blood pressure point signal b is generated, and a buffer memory 7 and the A/D converter that simultaneously display the systolic and diastolic blood pressure signals. 6, and a printer 10 that records the numerical values supplied from 6.

Reference numeral 20 denotes a blood pressure display waveform forming unit according to the present invention that displays non-invasively measured systolic and diastolic blood pressure as analog waveforms, and includes latch circuits 21 and 22 that hold the systolic and diastolic blood pressure signals as BCD signals. , a multiplexer 23 that switches continuously in synchronization with the clock pulse CP ₁ and alternately selects the output signals of the latch circuits 21 and 22, and a PWM that pulse width modulates the level of the selected blood pressure signal based on the clock pulse CP ₂ . (Pulse width modulation) circuit 2
4 and an R-C smoothing circuit 25 that demodulates its modulated output as an analog level signal, and the scale is adjusted so that the analog level matches the remote monitoring device that monitors it, that is, its scale is adjusted accurately. An analog level adjustment circuit, e.g., a variable resistor 26, for adjusting the level as measured, and an isolator, e.g., a photocoupler 27, for preventing accidental application of mains power to the remote monitoring device; A push button switch 28 to make the voltage zero, and an output terminal for sending an analog level signal and introducing a voltage for excitation of a transducer for an invasive blood pressure monitor to be used as the power supply voltage for the output side of the photocoupler 27 and the smoothing circuit 25. It consists of 29. The interval of the clock pulses CP ₁ input to the multiplexer 23 is preferably different from the normal pulse wave interval to facilitate differentiation from the invasive blood pressure waveform signal input interchangeably to the remote monitoring device. For example, it is set to 250ms. The interval of the clock pulses CP ₂ input to the PWM circuit 24 is set so that the systolic blood pressure can be sufficiently modulated by the number of pulses, that is, the time width, and the number of clock pulses CP 2 necessary for obtaining the desired flatness of the smooth demodulated analog level signal is 30, for example. The modulation signal of the degree is
For example, it is set to 13 μs so that it can occur within a 250 ms period. Since the PWM circuit 24 has two counting sections, it counts the clock pulses _CP2 up to a number corresponding to the blood pressure value loaded into the first counting section, and calculates the pulses with the time width required for the counting. After that, the output is stopped until the preset value of the second counting section is reached. That is, this second
After the time width set by the counting section has elapsed, the clock pulse _CP2 is counted again, and the PWM process of outputting and pausing the pulse of the counted time width is repeated about 30 times during the 250 ms interval of the clock pulse _CP1 .

Next, the operation will be explained.

When the pump 3 automatically increases or decreases the cuff 2 in the measurement/numerical display section 1, the transducer 5 detects the cuff pressure and responds to the A/D converter 6.
Output BCD signal. When the timing signal generation circuit 4 generates the systolic blood pressure point signal a during the pressure reduction process, the buffer memory 7 stores the output of the A/D converter 6 as the systolic blood pressure signal, and when the diastolic blood pressure signal b is subsequently generated, the buffer memory 7 stores the output of the A/D converter 6 as the systolic blood pressure signal. The output signal from buffer memory 7 is latched and displayed on the display 9 as the diastolic blood pressure value, and at the same time, the output signal from the buffer memory 7 is latched and displayed on the display 8 as the systolic blood pressure value, and the printer 10 prints out both blood pressure values. Ru. At this time, the diastolic blood pressure point signal b causes the latch circuits 21 and 22 of the blood pressure display waveform forming section 20 to hold the systolic and diastolic blood pressure signals. As a result, the BCD systolic and diastolic blood pressure signals alternately and continuously selected by the multiplexer 23 are converted to the clock pulse CP ₁ by the PWM circuit 24.
As shown in Fig. 2, the clock pulse CP ₂
Pulse width modulation corresponding to the number of pulse widths is performed repeatedly, and the modulated signal c is supplied to the smoothing circuit 25 through the photocoupler 27. As a result, the modulated signal c becomes a substantially flat rectangular analog waveform signal d due to the smoothing effect, as shown in FIG. Since the conversion to an analog level signal is performed after passing through the photocoupler 27, highly accurate analog leveling is possible regardless of its nonlinearity. Then, the level is adjusted by the variable resistor 26 to match the reading scale of the remote monitoring device, and the blood pressure display waveform signal e is continuously produced at levels corresponding to the systolic and diastolic blood pressures as shown in FIG. 4 with the time axis compressed. output terminal 29
It becomes possible to send from This signal transmission continues until the next pressurization/depression process of the pump 3, and is intermittently updated at predetermined intervals.

Such a blood pressure display waveform forming section 20 is formed, for example, as an adapter attached to the back of the blood pressure monitor main body, and a connector as an output terminal 29 is connected to the tip of a cable led out from the adapter, and a wireless remote monitoring device is connected. If desired, it can be connected to the cable end of a transmitter or a wired remote monitoring device in a manner compatible with an invasive blood pressure waveform signal.

The power for the smoothing circuit 25 and the photocoupler 27 can be supplied from a battery or from the main body side in an insulated state. In addition, the blood pressure display waveform forming section 2
0 can also be modified in various ways. For example, if it is acceptable to arrange photocouplers 31 in parallel to the latch circuits 21 and 22 for the number of bits as shown in FIG. The multiplexer 34 may also be of one circuit. The latch circuits 21 and 22 can also be used for the displays 8 and 9 of the measurement/numerical display section 1. Of course, various circuit configurations for the measurement/numeric display unit 1 are well known. When the systolic and diastolic blood pressure signals are aged using an analog type holding circuit, this circuit itself also functions as the analog level forming circuit according to the present invention. The blood pressure display waveform forming section 20 can be built into the non-invasive automatic blood pressure monitor body instead of the adapter. The blood pressure display waveform is not a simple rectangular waveform, but it is also conceivable to use another waveform type in which the period is the same as that of the pulse wave. The analog level adjustment circuit can also be a digital circuit.

Furthermore, in order to obtain the mean blood pressure according to the present invention, the multiplexer 23 or 34 is used to match the well-known approximate formula for non-invasive blood pressure monitors: mean blood pressure = systolic blood pressure - diastolic blood pressure / 3 + diastolic blood pressure.
If the time width for selecting the systolic blood pressure value is set to 1/3 of one cycle, the average blood pressure can be easily obtained by simply integrating the obtained signal.

As described above, with this invention, by displaying systolic and diastolic blood pressure measured non-invasively as analog levels alternately and continuously, when invasive blood pressure measurement is not necessary, it can be measured non-invasively through a normal remote monitoring device. It becomes possible to switch to a blood pressure monitor. By adjusting the signal level to match the remote monitoring device that can also be used as a monitor for an invasive blood pressure monitor, it is possible to measure blood pressure with such a remote monitoring device, and the maximum and minimum monitoring waveforms can also be monitored. Since the level fluctuation period between blood pressures is different from the normal pulse wave interval, it is easy to distinguish it from the invasive blood pressure waveform.

[Brief explanation of the drawing]

FIG. 1 shows the circuit configuration of a non-invasive automatic blood pressure monitor according to the present invention, FIGS. 2 to 4 show waveforms of various parts thereof, and FIG. 5 shows another embodiment of the present invention. 1...Measurement/numerical display unit of a conventional non-invasive automatic blood pressure monitor, 20...Blood pressure display waveform forming unit according to the present invention.

Claims (1)

[Claim for Utility Model Registration] During depressurization of the pump that automatically increases and decreases the pressure of the cuff intermittently, the systolic and diastolic blood pressure signals are detected and held in a holding circuit until the next automatic pressurization and depressurization process, and these signals are used as the systolic and diastolic blood pressure, respectively. A non-invasive automatic blood pressure monitor equipped with a display that displays numerical values includes an analog level forming circuit that generates an analog level signal corresponding to the systolic and diastolic blood pressure signals held, and an invasive blood pressure an analog level adjustment circuit that adjusts the level to match a remote monitoring device that can also be used as a monitor of the blood pressure meter; a multiplexer that selects at a cycle different from the normal pulse wave interval; and a blood pressure waveform display signal that alternately fluctuates between the level-adjusted systolic and diastolic blood pressure levels by selection of this multiplexer is output to the remote monitoring device; A non-invasive automatic blood pressure monitor characterized by having an output terminal.