DE2754334A1 - METHOD AND APPARATUS FOR DETERMINING SYSTOLIC PRESSURE USING INTEGRATION TO DETERMINE PULSE AMPLITUDE - Google Patents

Description

The invention relates generally to the field of blood pressure surprises and, more particularly, to automatic systolic blood pressure monitoring.

There are numerous prior art devices for Measuring a living being's systolic pressure. An ancient and simple device is a pressurizable cuff that is inserted into the Combination with a mercury manometer is applied, which reads the pressure in the cuff, and there is a stethoscope for listening to Korotkof sounds. A more advanced method of measuring blood pressure is removal from a blood pressure cuff to the wall of an artery precisely determined by measuring the Doppler shifts of the through the Artery reflected sound waves. Other methods of measuring blood pressure often insert devices directly into the Blood vessels introduced.

Oscillometer methods are also in the field known for determining systolic pressure. In such methods, the operator observes the representation of the strength the pressure pulsation arteries inside an artery. This can be done optically, e.g. by monitoring the amount of twitching at the top of a column of mercury in a mercury manometer pressurized with the cuff, or this can be done indirectly, e.g. by measuring the occlusion that enters the auricle in a blood vessel Applying pressure to the same. These oscillometric methods define systolic pressure as the greatest applied pressure at which threshold oscillations are observed. With a typical mercury manometer and a pressurized cuff, this pressure would then be the highest pressure the Operator observed twitching at the top of the mercury column as the pressure in the cuff is slowly and uniformly reduced. This procedure for determining the However, threshold oscillations are subject to inaccuracies, since the inertial force of the mercury column does not allow it to respond appreciably to pressure pulses of narrow width.

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Each of these modes of operation or devices for measuring systolic pressure has a disadvantage such as an inaccurate one Response to narrow width pressure pulses or the need to have an intricate and / or expensive meter.

In US-PS (US patent application SN 578 047) entitled "Apparatus and Method for Determining Systolic Pressure" ^ st a method and apparatus for automatic and relative simple execution of precise synthetic blood pressure measurements is described, odby overcoming the disadvantages of the prior art prefabrications. This device determines the systolic pressure by applying a pressure to a living being by changing the pressure in a pressure cuff, which is attached adjacent to a blood vessel. Here, an amount on the cuff is proportional to a time-dependent one Fluctuation component measured, which is characteristic of the pulsation pressure is in the blood vessel. This amount is proportional to the amplitude of the pulsating pressure and a determination is made of the highest value achieved by the amount when changing the pressure applied, and it continues to be an indicator for the highest pressure stored, as well as determined when the amount is practically equal to about half of the greatest pressure for one applied pressure is greater than the pressure applied when the greatest fourth or result occurs, as well as by reading out the applied pressure accordingly the amount which is practically equal to about half of the largest value as well as reading out the pressure which corresponds to the systolic pressure of the Living being. The signal coming from the pressure cuff has a fluctuating amount that is proportional to a Sum is and this sum consists of a time-dependent fluctuation component proportional to the amplitude of the pulsating pressure in the blood vessel and this component has a steep increase Waveform between the end of the diastole and the systole plus the selectively changeable pressure that is adjacent from the outside is acted upon the blood vessel through the cuff.

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With the device according to the above-mentioned US-PS (ÜSSN 578 047), the signal coming from the pressure cuff is applied to a screen network in order to remove the effects of the cuff pressure slope. The resulting oscillating signal is considered proportional to the amplitude of the pulsating pressure in the blood vessel and then a maxinuin-an-liaximura detector takes amplitude measurements which are used to complete the signal processing. An indiscriminate and uncontrollable deviation from the assumed linearity of the pressure slope can, however, introduce errors into this amplitude determination. There is a need for a large disturbance in the cuff pressure slope; Filter to recover over a considerable period of time and may allow some change in the baseline from which the fluctuating signal is measured proportional to the amplitude of the pulsating pressure in the blood vessel. too-maxiiaum detector yields.

According to the invention, a solution is now created for the problems those with occasional disturbances in the applied pressure slope of the cuff in a systolic blood pressure monitor of the type occur, v.ie it is described in the aforementioned US-S (USSN 578 047) is.

According to the invention an improvement of a device for the Determination of the systolic pressure of a living being described, which has the following components: a pressure cuff for the Applying a selectively changeable pressure to the living being adjacent to a blood vessel, transducer for measuring a fluctuating amount proportional to a sum, where the sum is a time-dependent fluctuating component proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure that is externally adjacent to by the cuff the blood vessel is acted upon, an arrangement for determining the maximum value that is reached by the fluctuating component when changing the application of the pressure, an arrangement for storing the characteristic of the maximum pressure, an arrangement for determining the fluctuating one Component, equal to a predetermined fraction of the maximum Is a value for an applied pressure that is greater than the applied pressure, if the maximum value results, and a

Arrangement for reading out the applied pressure accordingly dsr fluctuating component, which is practically equal to the previous

tireiiiten 3ruchteil of the maximum fourth is, v / ob with the read out Pressure corresponds to the systolic pressure of life, where the improvement achieved by the present invention specifically from the following consists: an arrangement for converting the fluctuating Quantity in an indicator of a time-derived amount of the fluctuating Component of the same, an arrangement for forming the time integral of the time-derived amount over an interval r.it predetermined limit values in each of the successive Blood pressure pulses, with the predetermined intervals of integration between the onset of the systolic rise and the systolic 'iaxin.un occur in the corresponding blood pressure pulses, : o how each of the integrals is proportional to the amplitude of the pulsating pressure for a corresponding pulse, as well Furthermore, an arrangement for the transfer of the time integral values to the arrangement for determining the maximum value.

In other respects, there is an improved method of determining of the systolic blood pressure is created, which has the following characteristics: it is pressure on a living being Changing the pressure in a Druckiaanschette applied to the is attached to the living person adjacent to a blood vessel to which Cuff is measured a ranks proportional to a sum

whether the sum of a time-dependent fluctuating component proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure applied by the cuff externally adjacent to the blood vessel, and the maximum fourth is determined, which is achieved by the fluctuating component when the applied pressure changes, an identifier of the maximum fourth is stored, and it is established that the fluctuating component is practically equal to a predetermined fraction of the maximum value for an applied pressure which is greater than the applied pressure Pressure is when the maximum value is obtained and the pressure applied is read out, which corresponds to the fluctuating component and is practically equal to the predetermined fraction of the maximum fourth, the value read out corresponding to the systolic pressure of the living being, according to the invention the following V procedural steps apply:

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Converting the amount, which is proportional to the Sunme, into a representation of a time-derived amount representing the fluctuating component thereof, determining the time integral of the time-derived amount over an interval of previously determined limit values in each of the successive blood pressure pulses, the pre-existing red interval of integration between the beginning of the systolic rise and the systolic peak occurs in the corresponding blood pressure impulses, where the determined integral is proportional to the amplitude of the pulsating pressure for the corresponding impulse and this time integral value is used to determine the naxinal I-th , which is achieved by the fluctuating component when changing the applied pressure.

The invention is based on the knowledge that the signal coming from the pressure cuff and especially the time-dependent fluctuating component thereof, which is characteristic of the pulsating pressure in the blood vessel, can be differentiated by forming the first time derivative of the fluctuating component. It was further found that this time derivative crosses a "zero baseline" in the positive direction at the time of end diastole and returns below the zero reference line as soon as the systolic maximum occurs at the end of the systolic rise. It was further found according to the invention that the "above zero" area under the time-derived waveform is indicative of the maximum-to- maximum (diastolic to systolic) amplitude of the corresponding blood pressure pulse, and that such an area can be determined by integrating the time-derived Waveform over its "zero dimension".

According to the invention it has furthermore been found that the double differentiation of the cuff signal in the lower frequency range of the cuff pressure slope helps to avoid a shift of the fluctuating component derivative from the envelope reference line.

The method according to the invention and the device according to the invention furthermore require an integration of the time derivative, if it passes through a reference value such as the zero value in the positive direction, and the integration is completed when the same passes through the extension line in the negative direction.

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BATH

Inventions 3 also include sampling and calibration of the integral value at the end of the integration period and a deletion of the Integration arrangement provided before the integration is carried out in the event of a subsequent blood pressure pulse.

Krfindungsgeriäß an improved arrangement and method is further provided through which a substantially periodic steep T ^T elle front of an input signal, with the possible presence of interference signals and low Ariplitude is identified possibly Intsrferenzsignalen high amplitude and low frequency and quantitated. Such an improved apparatus comprises an arrangement by which a signaling of the time derivative of at least the steeply rising I wavefront portion of the input signal is obtained, an arrangement for obtaining the time integral of the time derivative over an interval of predetermined limit values at j or successive repetitions of the steeply rising one v'ellenfront, where the interval is the side during which the time derivative rises above a predetermined value, an arrangement for the formation of a threshold value signal which is characteristic of the magnitude practically only of the time derivative, which is the steeply increasing value wavefront reflects a ^r .rordnung for comparing the time derivative of the train riingangssignals with Sch './ elleru / ortsigral v ^ hrenc ^first the Seitableituiig "is TBER the Dszugsvert under a control signal which gives an indication of whether or not the time derivative lies above the reference vert characterize c for an actually steeply rising cell front, as well as an arrangement which only responds to a verification note to the effect that a special time derivative is, however, according to the Fazugsvart, an actual steeply rising cell front for the recognition that the corresponding integral of the special time derivative is the quantized ^T .7srt the steeply rising 7? ellon front is.

.. In the method according to the invention, there is a change in the Input signal into a reproduction of a time derivative of at least one steeply rising wavefront part of the input signal, Determining the time integral of the time derivative over an interval predetermined limit values for each of the successive reproductions of the steeply rising V-cell front, ... with the interval is the time within which the time derivative over a previous

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determined reference value is formed, a threshold value signal that is indicative of the size of the tent discharge representing the steeply rising wavefront is the time derivative of the input signal with the threshold signal is compared while the time derivative is above the reference value and the formation of a control signal which gives an indication of whether or not the time derivative is above the reference value characterizing for an actually steeply rising wave front and as the quantized values of the corresponding steeply rising wave front Wavefront only the corresponding integrals are recognized, who receive a verification notice.

The method according to the invention and the device according to the invention further lead to the formation of the threshold value signal as a function of the size to be at least the immediately preceding one The time derivative above the reference value is above another reference value, the other reference value being normally is a zero reference value and the same as the reference value.

The method according to the invention and the device according to the invention furthermore lead to a double differentiation of the input signal in the low-frequency range to alternation of components high amplitude and low frequency.

According to one embodiment of the invention, the inventive leads Method and device according to the invention for integration the time derivative in a memory as soon as it is over goes beyond the reference value and it is then considered a valid integral. ert only recognized the integral obtained during the interval in which the time derivative is above the threshold at a point in time.

In a further embodiment according to the invention, a direct previous part of the time derivative with a duration of at least as long as the greatest expected duration of the rise temporarily stored for the steeply rising wave front. When the time derivative crosses the reference value in a negative direction and it has been determined that the time derivative is above the threshold during the immediately preceding "above zero"

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The stored time derivative is then used read out from the memory in a sequence introduced last and led out first, and the "above zero" part of the same is integrated in a memory to form the required integral value.

The device according to the invention is particularly useful as Ußberwachungsgerät for the blood pressure, whereby one the maximum anilaximum Value of each blood pressure pulse over the systolic rise (steeply rising waveform) from the end diastole to the systole want to measure. This knowledge of the maximum-at-maximum value of each In a preferred embodiment, this is accompanied by a bicut pressure pulse used to determine the systolic pressure of a living being. The input signal can come from a pressure cuff or other device. There is an arrangement for determining the the largest value is provided, which is obtained by successively determined (i.e. valid) integral values,. whether this Values correspond to the maximum-to-maximum value of the corresponding pulses. The largest determined integral value is stored and there is an arrangement for determining when the integral value is practically equal to about one half of the maximum integral for an applied pressure that is greater than the pressure applied by the cuff when a maximum Integral value, and the applied pressure at which this special half, maximum integral value occurs is read out as the systolic pressure.

An object of the invention is thus to provide an improved device and method for determining the to create systolic pressure. In this context, an improved method and apparatus is created, which with increased Determine the accuracy of the systolic pressure.

Another object of the invention is to an improved apparatus and method for identifying and quantifying a substantially periodically steep slope Wavefront in the presence or possible presence of low amplitude interference and possibly in the presence of

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High amplitude, low frequency interference ”.

An embodiment of the invention is shown in the drawings and is described in more detail below. Show it:

Fig. 1 shows a prior art operation for determining the maximum-to-maximum magnitude of the pulsating pressure in a blood vessel;

2 shows a mode of operation for the best mining of the maximum-to-maximum Amplitude of the pulsating pressure in a manner according to the invention;

3a shows a typical oscillometric envelope of the pulsating Pressure of a blood vessel;

Figure 3B shows the time derivative of the waveform of Figure 3A;

3C is a controlled timing diagram according to the invention Method and the device according to the invention;

FIG. 3D shows time intervals which, according to the invention, are based on the Waveform of Figure 3B are obtained;

4 shows a block diagram of the device according to the invention;

5 shows a plot of the gain against the frequency characteristics of a differentiating network applied in accordance with a preferred embodiment of the invention;

Figure 6A is an enlarged portion of the time-derived waveform of Figure 3B showing a verifying threshold and the timing of the various control states assigned in accordance with the invention according to ligur 4;

6B shows a control state diagram according to FIG. 6A and FIG Embodiment of Figure 4;

7 shows a flow diagram or decision tree of the control sequence, as used in the embodiment according to FIG. 4 between successive heartbeats;

FIG. 8 is an abbreviated block diagram supplemented by FIG and represents a further embodiment of the invention;

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9 shows a working mode similar to that of FIG. 2 for determining the maximum-to-maximum amplitude of the pulsating Drucks and further includes a threshold detector that derives the special "above zero" crossings of the waveform derivatives identified as valid Systolic Attacks.

Referring now to Figure 1, there is shown a functional block diagram of certain parts of the systolic pressure measuring device described in Ur above-referenced US-L'S (US Patent Application 578,047). In particular, the functional blocks of FIG. 1 show a filter network 100, the outlet of which is connected via the amplifier 102 to the input of a maximum-to-maximum detector 104. The filter network 100 receives an input signal on the input conductor 106. The input signal 106a has a slowly rising slope, which gives an indication of the applied cuff pressure and has superimposed on it the time-dependent fluctuating component, which is characteristic of the pulsating pressure in the blood vessel of the living being , and it has a steeply rising wavefront relative to the remaining components during the rise from end-diastole to systole. The filter network 100 is typically constructed in such a way that its output waveform 100a removed therefrom has the linear effects of the pressure slope, but any random and uncontrollable deviation from the assumed linearity of the pressure slope would introduce errors in the signal 100a. For example, if there is a significant disturbance in the cuff pressure slope, the filter 100 will take a considerable amount of time to recover and could allow some change in the baseline 100b (dotted) from which the fluctuating signal is proportional to the amplitude of the pulsating pressure in the Blood vessel was measured. Thus, each maximum-to-maximum detector 104 is actuated on the basis of the scanning signals 108, and the output signal 110a appearing on the line 110 contains these maximum-to-maximum errors introduced by the change in the baseline 10Ob.

According to the invention and as generally explained in FIG an input signal 206a having a waveform identical to that of waveform 106a of Figure 1 on the input conductor

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applied to the differentiating agitation 2OO. The differentiating Network 200 is constructed so that it does the same for a single differentiation of signal 206a over the range of frequencies, which leads to the frequencies of the fluctuating signal proportional to the amplitude of the pulsating pressure in the blood vessel and there is a double differentiation of the input signal below this range of frequencies in order to reduce the effects of the displacement to remove the linear pressure slope and any very low frequency interference that is in the otherwise linear Draft may have occurred.

A filter or differentiating network with the properties required for the network 200 will have the gain versus friency characteristics shown in FIG. ^UIM ^ ^e * - ^ne ~ 12db slope for frequencies below f ^ shows. The frequency range f ₁ - f ~ corresponds to the bandwidth

of the P signal, which has the fluctuating amount that characterizes ac . .

is indicative of the pulsating pressure. This part of the input signal 6a, which is characteristic of the pulsating blood pressure, is differentiated and occurs at the exit of the differentiating Network 200 as signal 200a, hereinafter P. on. The ρ signal 200a is fed through the amplifier 202 to the input of the integrator 204 is applied, which by integrating the P signal over a predetermined interval during each pulse produces an output

ert which is the maximum-to-maximum pressure of each blood pressure pulse is equivalent to. A sample-and-hold circuit 2Ο5 assigned to the integrator 204 is used to sample the at the output of the integrator 204 occurring at the end of each integration interval Value and holds this value for an interim period until the integration of the next pressure pulse begins. A control of the Integrator 204 and the sample and hold circuit 2 05 results from the reset / integration / hold signal 208, which is the integration period controls and serves to delete the integrator before each new integration. That from sample and hold circuit 205 Incoming output occurs on line 210 as a waveform 210a with a size corresponding to the area under that part of the integrating waveform P.

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Referring to Figures 3a and 3D for an understanding the theory on which the subject of the invention is based, it follows, taking into account the above-mentioned US-S (US patent application 578 047) that the systolic pressure is equal to the applied cuff pressure when the fluctuating amount is about is equal to one half of the maximum of the value of the fluctuating amount. The maximum value of the fluctuating amount is given by Measure diastole and systole in successive blood pressure pulses certainly. The impulse with the greatest P- 'amplitude becomes taken as the greatest value, and the applied cuff pressure is further increased such that the P-P amplitude decreases, and the systolic pressure is determined by determining the applied pressure Cuff pressure at which the P-P pressure assumes a value of half the P-P maximum.

FIG. 3Λ explains the time-dependent fluctuating component

P, which is indicative of the pulsating pressure in a blood geac

is a vessel. The root ED corresponds to each valley in the P waveform

cLC

the time of diastole or, more precisely, end diastole in the heartbeat, and the waveform set SP corresponds to the time of systole in the Heartbeat. As explained above, the signal firing from the cuff is differentiated by removing the applied signal Pressure slope and low frequency random noise and results in the derivative P of the waveform P as shown in Figure 3B. Since the waveform P has a zero slope at both the end

ac

diastole (ED) and the systole peak SP shows / ird the derived Waveform P will have zero magnitude at each of these times.

Since P still has a positive inclination during the systolic ac «

Shows a rise between ED and SP, the P waveform lies above the zero reference line during this interval. The zero crossing points ED and SP of the P waveform correspond to the points of maximum amplitude between successive P pulses and thus the area under the P waveform, xmd above the zero reference line between the end diastole ED and the systole peak SP there is a fourth, which is the P-P fourth of the corresponding blood pressure pulse is equivalent to. This area is determined by integrating over the zero portion of the P waveform. It should be noted that the Lnddiastole ED also essentially corresponds to the beginning of the rise to the systolic peak SP.

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Figure 3C illustrates a control signal generally similar to that Signal 208 according to FIG. 2, which clears or resets the integrator before the integration interval, then the P signal via the Integration interval Integrated and finally the integration. ert as a reproduction of the P-P value of the corresponding blood pressure pulse and holds it. This series of control operations is repeated with the reset operation shown by R- and the integration operation shown by S. and the sample and hold operation is represented by S + II. In fact, the sampled integral can be held longer than this is suggested by the short duration of the S + H signal in FIG. 3C.

The results of the integration of the P waveform between the limit values between ED and SP are shown in FIG. 3 D. The size of the integral at the time of the systolic peak SP corresponds to the P-P value of the corresponding blood pressure pulse.

Regarding the integration of the P waveform over the interval of the systolic rise while obtaining the corresponding P values for the corresponding blood pressure impulses or heartbeats a Conventional circuitry can be used for determining when the P waveform crosses the zero reference line in the positive Direction so as to begin the integration, as well as to determine ..then same the zero reference line in the negative Direction steps through so as to end the integration and / or to carry out the sampling and holding function. The integrator can be reset immediately after the sample and hold and preferably continues to work until the next step through

P takes place in the positive direction through the reference line. The resulting integral can then be used as indicative of the P-P value of the corresponding impulse apply. Certain Characteristics of the P-P waveform and / or the presence of signal interference during the sy diastolic decline, however, can cause P to briefly exceed the zero reference line except between the End diastole and the systolic peak occurs. As e.g. in the As illustrated in FIGS. 3A and 3B, if indiscriminate muscle activity a radio frequency signal disturbance (ART) is imminent of the end diastole, if the slope of the P _ waveform is relatively

ac

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tively flat, the derived P waveform is part of the signal interference present VJert as greater than zero and this leads to the provisional ones shown in parentheses in Figures 3C and 3D Values.

Mach an embodiment according to the invention as shown in FIG a threshold for discriminating between those P values greater than mull that occur in the systolic rise and those signals that are signal interference and the like are formed, which are not associated with the systolic rise. The magnitude of the P signal associated with the systolic rise is normal substantially larger than the size of any other (via Mull) part of the signal, e.g. resulting from signal interference, and accordingly this enables discrimination between such signals. Finding that the P waveform is above the threshold while the special "above Hull" passage is, the integration above this "above zero" passage between to verify the corresponding ED and SP limit values.

With reference to FIG. 9, in which those components which are functionally identical to the corresponding components of the 2, the input signal 206a is differentiated by the differentiating network 200 to form the

P waveform fed by amplifier 200 to the respective inputs of integrator 204, threshold detector 912, and Hull crossing detector 907. The mullion crossing detector 907, not shown in FIG. 2, can correspond to arrangements which define the integration interval and lead to the control signal 208 therein. The threshold detector 912 forms a threshold value of the signal magnitude above which it is assumed that the P waveform gives an indication of the valid systolic rise. If the incoming P waveform is above the threshold value of the detector 912, a signal is output at the input of the verification logic circuit 914, which gives an indication that this threshold value has been exceeded. Similarly, verifying logic circuit 914 receives an input from the output of zero crossing detector 907 to determine when the P waveform crosses a zero reference line in the positive direction and is also

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! .. " ⁱ⁷ ' 2Vb4334

if in the negative seal "crosses. The output 908 'of the verifying logic circuit 914 is connected to the reset input of the integrator 204 for the purpose of resetting the" intearator at least practically at the beginning of each desired integration period beginning with an overcrossing of the P V-shape of the * Tull reference line in the positive Direction. The output 908 of the verifying logic circuit 914 is connected to the "sample input" of the optional sample and hold circuit 205 and is used to store the value collected by the integrator 204 between the positive and negative crossings of the panel shape only if

hen the threshold detector 912 has given an indication of this has that the P. waveform was actually a valid systolic rise during this interval. The output signal 910 of the Sampling and Ilaltekreises 205 is different from the Output signal from 210 according to FIG. 2 only where the latter has an invalid output value that points to a systolic rise, although there was actually a signal disturbance. Albeit a threshold or fixed size above the zero reference line can be applied if a

"Above zero" part of the P waveform does not change size in consecutive Pulses showed, this is not the case, especially when using the oscillating transfer according to the invention

Ackon technique for the blood pressure, at which a pressure signal P of a small amplitude with a small applied pressure to a large amplitude with a larger applied pressure increases and then becomes a smaller amplitude with an even larger applied pressure. The one indicated as TRLD in FIG. 3B The threshold is thus selected to be a function of the magnitude of the systolic slope portion of the P signal over a or more of the immediately preceding blood pressure pulsations. The increase (and then decrease) in the size of the successive systolic increases in the P waveform is sufficiently gradual and the relative amplitude of any "above zero" is not systolic P ellenform slope components are sufficiently small such that a dynamic threshold is 50% of the maximum "Above zero" corresponds to the amplitude of the systolic rise of the P ellenform during the previous pulse, here as sufficient it is believed that only those "above zero" parts of the P waveform that are actually the systolic Increase. 8098 2 9/0618 -28-

It can be seen that the dynamic threshold value by summing and Weighting various previous systolic rise portions of the P waveform can be established, in this case the Threshold TRJjD can be at a preselected value, which is greater or less than 50% the size of the immediately preceding one systolic rise. An analogous example of a dynamic threshold detector of the kind used here is described in detail in U.S. Patent 3,590,811. A digital arrangement for establishing a dynamic threshold is described in detail below.

With reference to Figures 4, 6 and 7, there is one according to the invention Embodiment explained. The device is under With reference to the functional block diagram of FIG. 4, the digital processing of the received from the converter 23 is described Analog signals accomplished. It goes without saying, however, that an analogous mode of operation is possible in a similar manner. In particular discrete electronic components, discrete digital chips, microprocessor technology or digital computers can be used. Figures 6 and 7 show a state diagram and a flow diagram or decision tree relating to the processing of the P signal between successive blood pressure pulses correspondingly more successive Referring to heartbeats. Generally speaking, the signal processing stages correspond to those according to the invention Device, see Figures 6 and 7 of the device according to Figure 4, the P signal between the limit values ED -> SP integrated.

The arm 11 of a test person with artery 13 is treated with a typical Blood pressure cuff 15 wrapped around. Typically, the brachial artery present in the upper arm is used for this type of blood pressure measurement applied. A pump 19 and a pressure transducer 23 are connected to the cuff via lines 17 and 21. The converter 23 has a converter function such that the electrical output signal is essentially indicative of the signal supplied to it Pressure is up to the information limit present in the pulse pressure. The pressure transducer is used to measure the pressure in the Measure the cuff, which is the sum of the pressure applied by the pump and the fraction of the pressure caused by the blood pressure

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Fluctuations are formed in the artery, see waveforms 106a and 206a in Figures 1 and 2. The fluctuating part of the The output signal of the transducer 23 represents the amplitude of the pulsating pressure. The output signal of the transducer 23 is, see the line 24, an input of the multiplexer switch 25 is supplied. The output signal of the converter 23 is also, see the line 26, through the normally closed switch 27 fed to the input of a differentiating network 28. The output signal of the differentiating network 28 is, ie through the line 29 reproduced, fed to an amplifier 30 and see the line 31, ird then the other input of the multiplexer switch 25 supplied.

The differentiating network 28 differentiates the input signal over the f., -F _o bandwidth of the signal P-, see FIGS. 5, and

I ** aC

additionally performs a double differentiation of the frequencies under f ₁ . In this way, practically the only signal appearing on line 31 is that resulting from the differentiated (P) rendering of the P _a _ waveform.

The output signal of the multiplexer switch 25 is fed to an analog-to-digital (A / -) converter 33, as shown by the line 32. The output signal of the A / _n converter 33 is, as shown by the line 48, fed to the inputs of the gates 40 and 42, respectively. A clock generator 34 generates clock pulses which, ie reproduced by the line 35, are fed to a timing control unit 36 which controls the switching of the multiplexer 25, the conversion of the analog signal into a digital signal and the fading in of the gates 40 and 42. An output signal of the timing controller 36 is, as shown by the line 44, the multiplexer 25, A / converter 33 and the other input of the gate 40 supplied under control of the conversion of the P signal appearing on line 31 into digital form, which is then transmitted via the Reveal 48 is applied to the gate 40. Another output signal of the time control unit 36 is, as shown by the reveal 46, the multiplexer 25, A / _. Converter 33 and the other input of the gate 42, in order to control the conversion of the analog signal coming from the converter 23 into a digital form which is applied to the gate 42.

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The fade-in signals appearing on lines 44 and 46, which are fed to the inputs of gates 40 and 42, iron a sufficient duration in such a way that the digitally converted data assigned to the same and sent to the other input to the corresponding Gate occur through the special gate. Ilan also sees that the lines 44 and 46 reproduced control signals mutually mutually exclusive in such a way insist that the data appearing on lines 31 or 24 are fed to the most suitable port 40 or 42.

The period between successive blood pressure pulses is normally on the order of 800-1000 milliseconds, woei the systolic surge takes about 10 to 20% of each period. The P signal can be sampled across the systolic slope

• ·

a sufficient one. Number of increment parts (P.) of the P. line form can be integrated, closely approximating the area under the P waveform. Typically 10 to 20 samples are taken during the 100 to 200 milliseconds of the typical systemic rise sufficient to give the required number of P. increments and the rate of the clock 34 and control signals on line 44 are selected accordingly. One operates on line 46 at least once during each blood pressure pulse occurring control signal to the effect that the signal present on the line 24 is converted into digital form and the digitized Signal in the calculation and averaging unit 83 is transferred as a measure of the acted upon in the cuff 15 Pressure, as explained below.

Whenever a conversion and fade-in signal is on line 44 occurs coming from the time control unit 36, a time occurs

• ·

incremental sample P. of the P waveform at the output of the gate 40 on. This incremental sampling of the P waveform preferably occurs repeatedly during the blood pressure pulse and at least during the interval when the P waveform is above the ITuIl-]. reference value is. The timing of the system also results in sampling of the waveform on line 24 at least once during each pressure pulse at a time (s) other than the sampling of the P waveform on line 31 is in conflict.

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Each sample P. is from the gate 40, as represented by the line 50, the corresponding inputs ah the gate 52, comparator 54,,

■ - ■ ·

Comparator 56 and comparator 58 supplied. The P. input signal for the comparator 54 the »so-called zero reference value (P) compare that is present on line 60. The output signal of the comparator 54, as represented by the line 62, is set to a value which is indicative of the unit, if the P. point value that occurs at the input of the comoerator,

is greater than the zero reference value P_ and is set to a value

z ■■■■■■ - ■ ■

which is indicative of zero if it is equal to or is less than P_. The reference value P appearing on the line 60 is intended to correspond to the zero reference value of FIG. 3B. The voltage actually occurring on line 60 is adjustable and occurs as the voltage on the wiper of the potentiometer 20, the terminals of which with the voltages above or below a Voltage that correspond to the appropriate P_ voltage

- - - ·. ■■ * ■■■

can. To determine exactly the correct P voltage setting, . The switch 27 can be operated temporarily in such a way that a zero value occurs at the P. output of the gate 40 on the line 50 and the P "value on the line 60 is set so that is the same as that appearing on line 50. It can be seen that the P "voltage value on line 60 appears in digital form (via an A / _ converter not shown), namely for comparison with the digitized P. value appearing on line 50.

Whenever the P ₄ value exceeds P., the output

X Z '

signal on line 62 that the gate 52 transfers the special P., Fourth to the gate output, as shown by the line 64 is shown. Accordingly, the data value appearing on line 64 is indicative of a P ₁ value greater than P ₃₅ . Each such P ₄ value appearing on line 64 is applied to and accumulated in accumulator 66 which, by summing successive increments P, integrates the P waveform over the relevant interval from which the incremental samples were taken The accumulated sum of P, increments is available at the output of accumulator 66, such as

- 32 -

800829/0618

. 32 - 275433 *

represented by line 68 following the addition of each successive P. increnent to the sum. This output signal 68 coming from the accumulator 66 is fed as an input signal to the gate 70 for the controlled introduction into the "blow-to-blow" circuit, as explained further below.

The interval over which the accumulator accumulates 66 P. increments, is limited at its rear end by the P. increment, which is equal to or less than P compared to the Bull reference value.

. ζ

To identify this limit, the P. value is placed on the Line 50 and the P value on line 60 as the two input signals applied to the comparator 56, and the output signal, ·. Reproduced through the line 70, / is set from a zero value to a unit value, if P. is equal to or less

than P is.
ζ

A bistable element 72 has the effect that the output signal of the comparator 54, which occurs on the line 62, is fed to a "setting" input of the same for the purpose of setting the "U" output signal of the same to the unit value when P falls below P for the first time and the output of the comparator 54

goes from zero to the standard value. Similarly , the output signal of the comparator 56 on the line 70 is transferred via the delay element 74 to the "reset" input of the bistable element 72 in such a way that the Q output signal of the bistable element is set from zero to the unit value practically at the time where P. is no longer in a greater than zero state. In this way, the bistable element 72 serves to identify the interval within which the P increments of the waveform P go beyond P.

The Q output signal of the bistable element 72, ie represented by the line 76, is fed to the reset input of the accumulator 66 for the purpose of clearing or resetting the accumulator to zero when the Q output signal is at the uniformity value. The resetting of the accumulator 66 is intended to include not only the time at which the P waveform first moves toward or below the P reference value, but also within the time when it remains at or below P. In this

- 33 -

809829/0618

Thus, the accumulator 66 is prevented from being in any part of the P .. form of the arrow except for those above the P

Reference value lies. The delay element 74, which is a monostable Can be multivibrator or the like, is used to briefly delay the resetting of the bistable element 72 by an interval that is smaller than the interval between successive P. scans, but large enough to allow the resetting of the Accumulator 66 to delay until the final integral value occurring on line 68 through gate 78, ie explained below.

A fade-in pulse appearing on line 80 becomes the goal at the end of each systolic increase interval is applied in such a way that the time integral of the P waveform between the limit values ED and SP occurs at the output of the gate and, * ie through line 82 reproduced is fed to the beat-to-beat signal processing circuit. So that the fade-in impulses on of lead 80 occur only at the end of the systolic rise and not at the end of any other "above zero" portion of the P waveform associated with the dicrotic notch or the like are formed, the P 1 increments appearing on line 50 are matched in comparator 58 with one on line 84 occurring, stored threshold value compared with setting a bistable element 86, -enn the threshold value is exceeded.

The stored threshold value appearing on line 84 is one-half the size of the P 1 increment of maximum magnitude during the systolic rise of the previous one Blood pressure pulse, as explained below. The output signal coming from the comparator 58 is, as shown by the line 88, the "setting" input of the bistable multivibrator 86 and is transferred from the zero value to the unit value when the first P. increment is above the stored threshold value t. This makes the Q output value of the bistable Multivibrator 86 is set to the unit value at which it remains when a reset is made by a signal that occurs on line 70 which is fed to the "reset" input of the bistable element. The zero-to-unity signal

809829/0618

gang occurs on line 70 when P _.; is less than P for the first time. At this latter point in time, the Q output signal of the bistable element 86 is converted from the zero value to the unit value and this output signal, ie reproduced by the line 90, is fed to the inputs of the pulse generators 92 and 94, respectively.

The pulse generator 92 responds to the zero-to-unit input signal transitions while generating the output fade-in pulse, 'ie reproduced by the line 80, and thereby the on The integral value occurring on the line 68 is passed through the gate 78 to its output 82. It can be seen that the delay element 74 conditional delay is sufficient to show the integral value on line 68 through gate 78 before resetting of the accumulator 66 by the reset signal occurring on the line 16 to enable.

Regarding the provision of a dynamic threshold against which the P waveform is compared for verification or rejection at the above zero crossing of the waveform as a systolic rise, the signal appearing on line 64 becomes the indicative of P. increments greater than P on the input

X Z

of the comparator 95 and an input of the gate 96 out. The comparator 95, as represented by the line 97, controls the gate 96. The gate 96 serves to cause selected P. increments to be introduced into the storage unit 98 via the line 99. The P value stored in the memory unit 98 is fed to the other input of the comparator 95 via the line 120. The output of the comparator 95 '■■ ie represented by the line 97, goes from a zero value to a goal INFUNKTION releasing unit value whenever, νenn the incoming P, incremental

χ ·

ment is greater than the P. increment retained in storage unit 98. In this way, there is in the storage unit 98 Retained P. increment the P. increment of maximum size again compared to the time within which the special "above zero" Part of the P waveform is present.

At the point in time when the P waveform returns below the P, reference / value crosses, the value stored in the * unit 98 is indicative for the maximum P. (P. max), which occurs during the immediate

- 35 809829/0618

previous "above zero" P rarely occurs. The retained P ₁ max. Ert is applied to the "divided by two" circle 122 above line 124, developing the threshold

that is transferred to the storage unit 126. The actual division of the P ^ raax. However, the data and its storage in the unit 126 do not occur until a trigger or fade-in signal occurs on the line 128 from the output of the pulse generator 94. As with the fade-in signal 80 from the pulse generator 92, the fade-in signal 128 occurs only if the "above zero" crossing of the P waveform has been recognized as a valid systolic rise after comparison with the threshold value established by the previous systolic rise as this occurs to the lateral point where the P waveform comes below the P reference value. At this point the new ⁱ ^ ^{aaX value is introduced on line 130 into threshold storage unit} 126 on line 130 and becomes the new threshold against which the next "above zero" crossing of the P 'waveform is compared.

The "reset signal" represented by line 76 is shown in FIG similarly fed to the "reset" or cleared input of memory unit 98 shortly after the new threshold has been stored in the unit 126 for the purpose of erasing the memory unit 98. It can be seen that resetting the P ^ max. Memory unit 98 only enters when a "above zero" crossing of the P waveform is recognized as a systolic slope but also following any further "above zero" crossing of the P waveform, and this latter process is

required in order to avoid the occurrence of a disturbance P. value in the determination of P. max. and the development of a new threshold value.

Referring to the value represented by line 82 which encloses the time integral of the P waveform between the limits ED / SP, such a value is available for the purpose of loading after the conclusion of each corresponding systolic increase to the slide-to-slide circuitry described in the above referenced US-IS (US Patent Application 578 047). Short outlined, the P time integral runs on the line occurs, through nine optional average unit 39 (through

- 36 -809829/0618

dashed lines), which is an average of different, successive blood pressure pulses, e.g. four, and then, as represented by line 49, there is a transfer to the inputs of the comparator 43, gate 47 and systolic comparator 63. The comparator 43, like reproduced by line 45 controls gate 47. The gate enables entry into averaging unit 39 as through the Line 49 shown, the selected value of the (possibly average) P ^ ystolic slope integral introduced is, which is characteristic of the P-P fourth, ie reproduced by the line 51, then a transfer takes place in the Storage unit 53.

The fourth of the amount stored in the memory 53 is fed to the comparator 43, as represented by the line 55. Inside the comparator 43 are the stored previous representations of the provisional maximum value of the P-systolic Increase integral compared with the current values of the amount that is reproduced in the comparator 43, ie through the line 49, is introduced, ο the fourth of this to the comparator 43 The amount supplied through the line 49 is greater than the amount provisionally stored in the storage unit 53, ie by means of the line 55 is fed to the comparator 43, the gate 47 is then activated by the comparator 43 via the line 45 is set and the larger V7ert of this amount replaces the provisional maximum value in the storage unit 53.

The provisional maximum value of the P-P amount, as indicated by the line 57 reproduced, divided into a halving unit (divided by two) 59, in which a division takes place in half. The fourth divided into half is fed to the systolic comparator 63 as indicated by the line 61. The (now) The current value of the (possibly average) P systolic increase interval becomes the systolic via line 49 Comparator 61 is supplied. If the systollsche comparator determines that the same amount supplied via line 49 less than or equal to half of the provisional maximum

- 37 -

809829/0618

Is the value that is fed via the line 61, the systolic comparator 63, as shown by the line 67, indicates that the switching arrangement 69 stops the pump 19 and out of the Cuff 15 lets out air through the control valve line 20, although the order to stop and let out air is shown through line 71.

The switching arrangement 69, as represented by the line 73, and the systolic comparators 63, ie represented by the line 93, also arrange that the interpolation unit 75 between the values of the applied pressure, i.e. interpolates the pressure supplied to the cuff 15 by the pump 19, uri to determine the exact applied pressure, which corresponds to this amount (P-P), which is about half of the maximum Worth.

The values of the applied pressure are fed to the interpolation unit 75, ie reproduced by the lines 77 and 79. The line 77 reflects the introduction of the applied pressure value, specifically for the measurement immediately before the quantity was less than half of the maximum value, and the line 79 shows the pressure applied again, if the amount is equal or is slightly less than one half of the maximum value. In other words, line 79 represents the most recent value of the pressure applied. These values of the acted upon By introducing the digitized waveform of the line 24 from the transducer 23 through the port 42 to a pressure (last) "! -primest" storage unit 83 which contains an average value of the signal over the last "n" (e.g. recent blood pressure itopulse forms. When each new one occurs Blood pressure pulse, the average value occurring in the average and storage unit 83 becomes immediately with the previous average value, <-; ie reproduced by the line 89, modernized and fed to the storage unit 81, the then saves the "just previous" average value.

It is usually used for what is on line 24 The analog signal will be sufficient to be converted into the digital value practically at the time of the systolic peak SP, e.g. using the signal from bistable element 86 and appearing on line 90 as a timing input

809829/0618 - 38 -

for the timing unit 36. Essentially, the analog signal appearing on the line 24, which is finally converted into a digitized Form occurs on the line 48, from the slowly increasing pressure slope,. With only a very small fluctuating Amount is present, which is characteristic of the pulsating pressure superimposed on it. Thus, the one occurring on line 24 will be Value practically proportional to the pressure applied by the cuff and is represented as "P," it can however, low pass filters can also be introduced into line 24 if appropriate for removing the pulsating component .

Certain obvious aspects and controls of the Figure 4 embodiment have been omitted here and there includes, for example, the application of an initiation signal, "enn die Pump 19 is put into operation for the purpose of erasing and / or resetting essentially all storage elements to a corresponding one Original value. Normally, this initial value will be regarded as a "zero state". However, it may prove to be useful prove to first store a smallest threshold value in the threshold value storage unit 126 which is not a zero value represents, such that the verification of the systolic rise takes place at the first blood pressure pulse.

Furthermore, the systolic rising portion of the P waveform can be over greater or lesser limit values than the preferred ED-SP limit values be integrated to form a value that is essentially indicative of the P-P value of the corresponding blood pressure pulse is. In such a case, the so-called P_ reference value appearing on line 60 and by the various Comparators are used, assume a value that is slightly above or below zero.

Although P. max. Has been divided by two, it is further understood that another suitable divisor with practically the same value e ± n -other can also be used if the cuff 15 and / or the arm of the patient are of this type exist that the cuff applies a maximum pressure on one side or the other side of the normal position in the center of the cuff.

- 39 -

809829/0618

Furthermore, with regard to the explanation of FIG. 4, in particular with a view to digitizing the P waveform, determining the systolic slope limits and determining of a valid systolic rise, this is essentially only one of possible alternative circuit systems for implementation reflect the invention. For example, the determination of when the

P waveform goes above and below P "and whether or not a valid systolic surge has occurred can be performed using the analog P waveform prior to digitization and such determinations can then be used to control those Portions of the P waveform are applied as P increments for insertion into the accumulator 66 can be applied. Further- -tin can be the comparator 56 and "state indicating" bistable Elements 72 and 86 are omitted if the comparators 54 and 58 only worked on analog vials or in other formats Way the same is continuously supplied with the digital signal information.

It is understood by the person skilled in the art that the various functions shown in FIG. 4 are carried out by conventional commercially available components. With the exception of the pneumatics, pneumatic controls, and the original analog circuitry associated with transducer 23, the remaining functional blocks from commercially available microprocessors and other digital circuit elements built up. The following is a brief description of the state diagram according to the 6B and the associated waveform according to FIG. 6A, and a flow chart or decision tree according to FIG Heartbeats is applied.

Figure 6A shows part of the P waveform and divides the Waveform according to time in five different states, which are shown in the signal processing state diagram shown in FIG. 6B assigned. The state diagram and further details The decision tree according to FIG. 7, derived therefrom, provides sufficient information for the person skilled in the art. in order to build the device according to the invention of digital construction, e.g. with microprocessors.

- 40 -

809829/0618

With reference to FIG. 7 and the instruction sequence given by it between the systolic peak SP and the end diastole LD of the previous blood pressure pulse and thus before the beginning of the systolic rise of the current pressure pulse, the memory unit 93 containing P max

^x fs? '

Storage unit (accumulator 66, which contains the sum _BD J p)

next deleted as well. Then there is a short time increment the row form is converted into a digital fourth, represented by P., which indicates the size of the special increment. Assuming that the system is in state (one "or possibly" two "of waveform P, then P. compared to P. If P is less than or equal to P, remains

Zx Z

the system in the "-: ins" state and the sequence returns to the "delete."

• ·

P. Total step back and is repeated. On the other hand, if P. χ. χ

is greater than P, the state "two" is entered, and ζ. . ·

the size of P, above the reference P, becomes the sum of the P. incre- _ ζ ι.

ments (in the accumulator 66) are added, whereby the value of the P. Sum is increased.

A determination is then made as to whether or not a valid systolic rise has been recognized by the setting of a "V. Threshold" flag. Assuming that the "V flag" has not yet been set, * ie this is the case until the state "three" has been introduced according to FIGS. 6A and 6B, the sequence will then consider whether P. is less than the threshold is. Since the system is still in the "two" state, the program will then branch and the sequence beginning with the conversion of the next increment of the P waveform into a P. will be repeated. The sequence of the state "two" continues until P ₁ is>. ^a ^ - ^s the threshold value, and at this point in time the "threshold value flag" is set and the transition from state "two" to state "three" takes place.

The sequence then determines whether or not the special

P. is smaller than the stored fourth P max. Since P. max. Through χ. χ

the largest previous P. increment is determined, a

new P. normally smaller than P. max. in the state "three"

i j-

be. Thus the sequence for the current value of P.

- 41 -

809829/0618

the P. max. storage location is to be transferred to the fact that a new P. max. Is formed. The sequence then determines whether or not

• X · ·

P. is greater than P_. Assuming that P. is either in the

XZ X

State "three" or in state "four": e finds it will be greater than P ₂ and accordingly the sequence returns to the stage / o converting the P waveform to a new P. increment and the

Xr

Sequence is repeated. In this way, the P. increments

• J-

continuously added to the stored P ₁ sum over the state "three" or "four" and the state "two".

When the P waveform peak is reached, namely in the transition from state "three" to state "four", a maximum P. will occur and each subsequent P. will normally be one have a value less than P, max., which was retained in the memory at the top. Thus the sequence branches the step, which would otherwise be the value of the now smaller P.

• X

would be transferred to the P. max. memory.

The transition from the state "four" to the state "five" requires

that a new P. is no longer greater than P_, and the sequence

X Z

recognizes that the integration has been completed. Then P. can be scaled as required. The scaled P. total is stored in a location that is indicative of the maximum-to-maximum (P-P) size of the corresponding blood pressure pulse, namely for the application at the intermediate stroke processing.

Finally, the previously saved value in P. max. Is displayed and this wager is stored in a location indicative of the threshold value forming the threshold value for the subsequent impulse. It can be seen that the threshold increases as the size of the final P.max in each pulse increases

X ·

and in a similar way with the decrease of the final P ^ max. The "V threshold value flag", which was previously set, is reset either now or at the end of the present sequence or optionally at the beginning of the sequence in the sequence in the next blood pressure pulse.

- 42 -809829/0618

If a special state "two" never exceeds the threshold value (state three) before it falls below P (like this

the case is in the presence of a fault) the "V threshold - return flag" will remain in the deferred state. Although Pi increments continuously to the P. sum during this state d "two" are added during the interval, but they are not subsequently considered to be a valid T7ert, since the "five" threshold flag has not yet been set and the sequence branches back to the "Delete P ^ Sum" Step while the 'Jellenform P remains under continuous

• Z

Deletion of the P. summation memory element.

Referring to Figure 8, there is an optional one in accordance with the present invention Embodiment reproduced in which it is appropriate may prove to store a larger portion of the P waveform than would be reproduced by a single P. increment will. In such a system, integration of the appropriate intervals of the P waveform can be achieved by using the "above zero" *·_. Data value is read that is in another Memory is present and is introduced into the integration arrangement, such as the accumulator 66 according to FIG. 4, from where the data values can then be further processed in the same way as has been explained with reference to FIG. Each of the Elements of the embodiment according to FIG. 4, which are common to the elements according to the embodiment of FIG. 8, and which are here do not contribute to the further understanding of the subject matter of the invention, are omitted from FIG. In a similar way those elements and functions are according to the embodiment of the FIG. 4, which are identical to that according to FIG. 8, numbered in a similar manner and reproduced in FIG.

The P. increments 50 are on the front input of the last imported and first read out (LIFO) memory element or memory 569. Memory 569 has one Word length of "m" units, where "m" corresponds to the number of P. increments that occur during a systolic rise the maximum expected duration (i.e. lowest anticipated pulse rate). This can range from about 20 to

- 43 -

809829/0618

25 P ₁ increments act. The zero crossing and the threshold detection circuit of Figure 4 operate to bring the Q output of the bistable 96 to the unit value at the time the P waveform becomes equal to or less than zero, below that Assumption that the threshold has been exceeded. This positive exceeding of the Q output signal of the bistable element 86 occurs on the line 90 and is fed as an input signal to the »pulse generator 564, which in turn forms a pulse output signal on the line 565, which is fed to the functional input of the LIFO circuit 566. The LIFO circuit 566 receives an input signal from the timing circuit 36 via the line 567 and, once activated, it operates in such a way that opposing pulses are supplied in the LIFO memory 569. These opposite pulses result in the P. data stored in LIFO memory 569 being read therefrom on line 64 'in the opposite order in which it was introduced. The timing control 36 * I: can deliver pulses at a rate sufficient for the entire contents of the memory 569, which is read in the opposite direction between successive feeds of new P. increments. However, if the rate of these pulses from timing controller 36 * is slower, it may be necessary to inhibit the delivery of new P 1 increments 50 to memory 569 during LIFO readout.

The P. increment which has led to the positive conversion of the Q output signal of the bistable element 86 is as such not stored in memory 569 and so the last P. increment introduced will have a small psotential value. if the content of memory 569 is read out in the opposite order, becomes that occurring on line 64 ' The data value will initially have a positive value and will increase in the positive direction and then decrease in the PJ direction towards the zero reference point in the opposite sequence compared to the one with which it was initially saved is. The line 64 * is connected to an input of a comparator 560 connected, and the other input of the same is the P_ reference point

■ ■ - z

- 44 -

80 9129 ifÖ618

60. The Xoiaperator 560 goes from the ITull value to the unit value v / if the data appearing on the line 64 'are the same or ground less than the P reference point. The output signal of the comparator 560 becomes the input of a pulse generator via line 561 S 562 is supplied for the purpose of generating output pulses as soon as the operator makes a transition from the zero value to the on-side value power. The output of the pulse generator 562 is applied via line 563 to an inoperative input of the LIFO control circuit 566, so as to continue applying oppositely directed impulses to the LIFO memory 569 to inhibit. Xn this way, the on line 64 occurring P. data temporally opposite data values above zero, which are indicative of a valid systolic Increase in blood pressure pulse.

The data values present on the line 64 'are fed to the accumulator 66, in which they are summed up in the manner described above. The light coming from the accumulator 66 output signal is fed to the input of the gate 78 via line 68 ·. The control pulse 80 applied to the gate 78 serves to lead the resulting sum accumulated in the accumulator 66 through the gate 78 to its output , as shown by the line 82 and then to the processing circuit (not shown) as described above has been explained with reference to FIG.

809829/061 8

Blank

Claims (1)

PATENT ADVERTISER D-I BERLIN 33 11/26/77 MANFREDMIEHE "r _{/ 00 /} FALKSNRIEO 4 2 / 04o3H Telephone: * »» · M »so Dlplom-Chcmikcr · ^ ^ ^ Tdtr «« »« i indusprop berlin TeUx: OH5443 ÜS / 02/2367 ΛΟ-2986 ON AMERICAN OPTICAL CORPORATI Southbridge, Mass. 01550, USA Method and apparatus for determining systolic pressure using integration to determine pulse amplitude Patent claims .J device for determining the systolic pressure of a living being, which includes an arrangement for the application of a selectively variable pressure on the living being adjacent to a blood vessel, an arrangement for measuring a fluctuating amount proportional to a sum, ..wherein the sum of a time-dependent, fluctuating component proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure applied externally adjacent to the blood vessel there is an arrangement for determining the greatest value reached by the fluctuating component when changing the applied pressure, an arrangement for storing a representation of the maximum value, an arrangement for detection when the fluctuating component practically equals a predetermined fraction of the greatest value for an applied Is pressure which is greater than the applied pressure .. when the maximum value results, and an arrangement for reading it out of the applied pressure corresponding to the fluctuating component, which is practically equal to a predetermined fraction of the is the maximum value, the read-out pressure corresponds to the systolic pressure of the living being, is present, characterized in that an arrangement for converting the amount into a representation of a time derivative of the fluctuating component thereof, an arrangement for forming the time integral 809829/0618 ~ ² ~ the timing over an interval of predetermined limit values in each successive pulse of blood pressure, v / obei das Integration interval between the beginning of the systolic rise and the systolic peak in the corresponding blood pressure impulses occurs so / ie each integral proportional to the amplitude of the pulsating pressure for the corresponding pulse and an arrangement for transferring the time integral to the arrangement for determining the maximum fourth. 2. Apparatus according to claim 1, characterized in that the predetermined integration intervals differ from the beginning of the systolic rise to the systolic peak in the corresponding blood pressure pulses extend. 3. Apparatus according to claim 1, characterized in that the arrangement for forming the time integral resettable integration arrangement, an arrangement based on the time derivative for resetting the integration arrangement in responsive to an initial state, an arrangement that responds to the time derivative for initiating the integration of the time derivative responds at a selected start of time and has an arrangement that is responsive to the time derivative for the sampling of the Responds to the integral value that has been collected by the integration arrangement at a selected sampling time for the Transfer to the arrangement for determining the maximum fourth. 4. Apparatus according to claim 3, characterized in that that the time derivative is a reference in one direction at the beginning of the systolic rise and the reference in the opposite direction Direction at the systolic tip crosses, the arrangement for starting the integration and the sensing arrangement respond to the derivation of time * the reference terms crosses the first and the opposite direction so as to start the integration and the sampling of the integrated value. 5. Apparatus according to claim 4, characterized in that that the reset arrangement is responsive to the time derivative for the purpose of resetting the integration arrangement when the time derivative is in the opposite direction with respect to the reference quantity. 809829/0618 ~ ³ ~ 6. Apparatus according to claim 5, characterized in that the resetting arrangement interrupts the resetting of an integration arrangement practically at your point in time, ο the integration begins. 7. Apparatus according to claim 6, characterized in that that the reference is practically zero and the magnitude of the time derivative is greater than zero during the systolic rise. 8. Apparatus according to claim 3, characterized in that an arrangement for converting the time derivative into successive time-coordinated increments are present, the increments of the integration arrangement for the purpose of integrating the same are fed. 9. Performing according to claim 1, characterized in that the arrangement for converting the quantity is a differentiating one Network for converting the quantity into a representation of the first temporal variation of the same over the Frequency band of the fluctuating component and for converting the quantity into a representation of the second time derivative thereof at the lower frequency of the selectively variable pressure. 10. A method for determining the systolic pressure of a living being, in which a selectively variable pressure is applied to the living being adjacent to the blood vessel, a length proportional is measured to a sum, the sum being a time-dependent fluctuating component proportional to the amplitude of the pulsating Pressure in the blood vessel plus the selectively changeable Pressure applied externally adjacent to the blood vessel, which is caused by the fluctuating component when changing the applied pressure reached maximum value Representation of the maximum value is stored, as well as it is determined when the fluctuating component practically equals one predetermined fraction of the maximum value for an applied Is pressure which is greater than the applied pressure, if the maximum value results, as well as the applied pressure -A- 809829/061 which corresponds to the fluctuating component and practically equal to a predetermined fraction of the maximum Value is that the pressure read out corresponds to the systolic pressure of the living esens, characterized in that the amount proportional to the sum is converted into a representation of a time derivative of the fluctuating component thereof, the time integral of the time derivative is determined over an interval of predetermined limit values in each of the successive blood pressure pulses, the predetermined integration interval between the beginning of the systolic rise and peak systolic in the corresponding Blutdruckirripulsen occurs, whereby the detected integral is proportional to the amplitude of the pulsating pressure to the pulsating pulse, as well as the reproduction of the Zeitintograls maximum in Bestmnung Ces value applied v / ground, the at by the fluctuating component Changing the applied pressure is achieved. •• 11ee —- ^ essential periodic, ... partly rising wave front etnejr signal, where the F-signal feed occurs in the possible presence of interference with low amplitude, thereby g ^ -eke η η indicates that an arrangement for the formation of a reproduction a lateral derivative of at least the steeply rising wavefront part of the r.input signal, an arrangement for forming the time integral of the time derivative over ^ Xn predetermined interval in each of the successive repetitions of the ι steeply rising "rush front, where the interval is the time, within which the time derivative over a predetermined reference value increases, an arrangement for forming a threshold signal, this is practically purely indicative of the size of the time derivative is / ^ aie characteristic of the steeply rising Wavefront is use an arrangement for comparing the time derivative of the input signal with the threshold value signal during the time elapse above the reference value increases with training a control signal which gives an indication of whether or not the time derivative is above the reference value and is indicative e 809829/0618 BAOJGRQmAL '"; - /.' 275A33A / on after a special time derivative lying over the jjßzugswört a valid, steeply rising, -Werlehfront is for the purpose of recognition of the correchejjdeft-InTifegral of the special time derivative as the 1 ^. Device according to Claim 1, characterized in that the arrangement for forming the threshold value signal trains it as a function of size, uri that at least the immediately preceding time derivative is above the reference value and exceeds a further reference value. i3> Device according to claim 1, characterized in that the reference value and the other reference value are the same. A. Apparatus according to claim 3, characterized in that the threshold value is proportional only to the size by which the immediately preceding time derivative is above the reference value. iff. Apparatus according to claim 4, characterized in that the input signal is additionally present in the possible presence of high amplitude and low frequency interference, as well as the arrangement for establishing the time derivative a differentiating network for converting the input signal into a representation of the first time derivative thereof a frequency band including the steeply rising wavefront and in a representation of the second derivative thereof at the has a lower frequency of the high amplitude, low frequency interference that may be present. i £ 7 Device according to claim 4, characterized in that the threshold value is practically 50? the one above that Reference value lying magnitude of the immediately preceding time derivative. φ. Device according to Claim 1, characterized in that the arrangement for forming the time integral of the time derivative comprises an accumulator, the time derivative is introduced into the accumulator and accumulated therein during each interval within which the same is above the reference value, the accumulated value of each of the above the reference value 809829/0618 - ο - Intervals has a provisional value of the integral, the Systolic Slope Verification Arrangement works so that only those integrals corresponding to valid systolic increases in the assignment for determining the maximum Integral value are supplied, with only those provisional integrals that receive verification as the corresponding quantized fourth of the corresponding, steeply rising urine fronts are recognized. ί Apparatus according to claim 7, characterized in that the input signal is obtained from an ilcuff measuring the blood pressure and represents a sum which contains a time-dependent fluctuating component proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure which is externally adjacent applied to the blood vessel, the fluctuating component of the input signal normally has a periodic, steeply rising wavefront part which is characteristic of the systolic rise, and furthermore an arrangement for determining the greatest value which is achieved by successive integrals during the applied pressure in the cuff is varied, an arrangement for storing a representation of the largest integral value, an arrangement for determining when the integral is practically equal to about half the maximum integral value for an applied cuff pressure, the is greater than the pressure that is then applied,. If the maximum integral value is obtained and has an arrangement for reading out the applied pressure corresponding to the integral, which is practically equal to approximately half the maximum value, as an indication of the patient's systolic pressure. λ9. Device for determining the systolic pressure of a living being, characterized in that an arrangement for applying a selectively variable pressure to the living being adjacent to a blood vessel, an arrangement for measuring a fluctuating amount proportional to a sum, v. The sum of a time-dependent fluctuating component proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure that is externally adjacent to the 809829/0618 - ⁷ " Blood vessel is acted upon, there is an arrangement for transforming the amount into a representation of a time derivative of the fluctuating Component of the same, an arrangement for the formation of the time integral of the time derivative over a predetermined interval Limit values in each of the successive blood pressure pulses, the interval being the time within which the time derivative rises above a predetermined reference value, an arrangement for the determination of the greatest value that is achieved by successive integrals when the applied blood pressure changes, an arrangement for storing a representation of the maximum integral value, an arrangement for determining when an integral is is practically equal to a predetermined fraction of the maximum integral value for an applied pressure which is greater than is the pressure that is applied when the maximum integral value is results in an arrangement for reading out the applied pressure according to the integral, which is practically the same the predetermined fraction of the maximum value is the read out Pressure corresponds to the systolic pressure of the living being, there is an arrangement for the formation of a threshold value signal, which is indicative of the size practically only the time derivative reproduced the systolic rise, one Arrangement for comparing the time derivative of the fluctuating component of the set with the threshold signal during the time derivative is above the reference value with the formation of a control signal which gives an indication of whether or not the Time derivative lying above the reference value is characteristic of a valid systolic and an arrangement is present that only is responsive to verification that the particular time derivative above the reference value is a systolic rise for the purpose of transferring the integral to the device for determining the maximum integral value and the arrangement for determining the fraction of the maximum integral value. Device according to claim 9, characterized in that that the arrangement for forming the threshold value signal forms the same as a function of the magnitude by the at least immediately preceding lateral derivation above the reference value beyond a further reference value. 809829/0610 - 8 - 2φ. Device according to claim D, characterized in that the 7> pull value and the other t pull value are the same. o — a net that the threshold value is only proportional to the size is to transfer the previous time derivative over to the __dO £ - «nrT ± Device according to Claim 9, characterized in that the device is designated as a t that the arrangement for forming the time integral of the time derivative is an accumulator on v / e, the time derivative dem Accumulator is fed and accumulated therein during each Interval in which the same is above the reference value, the accumulated liert jeues about deir. Reference value has a corresponding provisional integral, the verification arrangement for the systolic rise works in such a way that the integrals of the Arrangement for determining the maximum integral value are supplied. 2 ^. Device according to claim 14, characterized in that that an arrangement is provided for erasing the accumulator before each subsequent integration accumulation. 28. The device according to claim 14, characterized in that that an arrangement for converting at least the parts of the time derivative above the reference value into successive ones timed discrete increments of the same are present, as well as the accumulator sums the discrete increments that are above the reference value. 2t ". Device according to claim 13, characterized in that the arrangement for forming the time integral of the time derivative has an accumulator, the time derivative is fed to the accumulator and is accumulated therein during each interval at which the same is above the reference value, the accumulated value of the intervals above the reference value 809829/0618 BATH ORIGINAL has a corresponding provisional integral, the verifying arrangement for the systolic rise works in such a way that only those integrals are transferred to the arrangement for determining the maximum integral value which valid systolic increases are assigned. Device according to Claim 9, characterized in that the arrangement for forming the time integral of Time derivative an accumulator, an arrangement for temporarily storing that part of the time derivative that is about a immediately preceding interval extends, the immediately preceding interval being at least exactly as long as the maximum expected duration of the systolic rise part of the blood pressure impulses, an arrangement which is responsive to the time derivative, which goes from a value above the reference value to a value which does not exceed the reference value and which responds to an indication of a valid systolic increase based on the verification arrangement for the purpose of influencing one introduced last and as the first read-out signal of the part of the time derivative which is stored in the memory, an arrangement for transferring the part read out from the memory to the accumulator and for accumulating only those values of the read part which is above the reference value, whereby the value of the read-out time lapse, which is accumulated by the accumulator, is fed to the arrangement for determining the maximum integral value. 2f). Device according to Claim 18, characterized in that there is an arrangement for erasing the accumulator before each subsequent integration accumulation. 2ψς device according to claim 13, characterized in that the arrangement for forming the time integral of the time derivative an accumulator, an arrangement for the temporary storage of the part of the time derivative that extends over an immediately preceding interval, the immediately preceding interval at least as long as is the maximum expected duration of the systolic rise portion of the blood pressure pulses, an arrangement which is responsive to the time derivative being from a value above the reference value to a value not above the reference value and to a 09 * 2 * / β * 1 - ίο - QAS 275A334 An indication of a valid systolic rise established by a verification arrangement for conversion of the last introduced and first read out portion of that part of the time derivative stored in the memory is, an arrangement for the transfer of the read from the memory Part for the accumulator and for accumulating only those values of the read part that are above the reference word lie whether the 'Jert of the extracted time derivative, the is accumulated by the accumulator supplied to the arrangement for determining the maximum integral value. "3Φ. Method for determining the systolic pressure of a living being, ; - <ei which a selectively changeable pressure on the living being acted upon adjacent to a blood vessel, a lot is measured proportionally to a sum, the sum of a time-dependent fluctuating component being proportional to the amplitude of the pulsating pressure in the blood vessel plus the selectively variable pressure that is externally adjacent to the blood vessel is applied, this amount is converted into a representation of a time derivative of the fluctuating component of the same, the time integral of the time derivative over a predetermined interval Limit values are determined in each of the successive blood pressure pulses, ... with the interval being the time, within which the time derivative is above a predetermined reference value, which is determined by the fluctuating component when changing of the applied pressure is determined, the reproduction of the maximum integral value is stored and determined becomes when the integral value is practically equal to a predetermined one Fraction of the maximum integral value for an applied pressure that is greater than the pressure that is then is applied when the maximum integral value is obtained, as well as the applied pressure is read out, which corresponds to the integral \ .ert, which is practically equal to the predetermined fraction of the maximum integral value is, ' Pressure corresponds to the systolic pressure of the living being, characterized in that a threshold value signal is formed which is characteristic of the size practically only the time derivative representing a systolic rise, this time derivative the fluctuating component of the quantity is compared with the threshold signal, while the time derivation over the reference 809829/0618 - n - . ert lies under the aid of a control signal which is an indication dfarauf shows whether or not the time derivative is above the reference value, indicative of a valid systolic increase and only the integral values of the time derivative are used, which are a valid systemic increase in the determinations of the maximum integral value and the fraction of the maximum integral value. Jl6j £ 4-. A device for determining the blood pressure of a living being, which includes an arrangement for applying a selectively variable pressure to the living being adjacent to a blood vessel, an arrangement for measuring a fluctuating lienge proportional to a sum, the sum of a time-dependent fluctuating component proportional to the Amplitude of the pulsating pressure in the blood vessel plus the. ¹ , selectively changeable pressure which is applied externally adjacent to the blood vessel v? IrcT, ... is an arrangement for converting the quantity into a? 7iac successive blood pressure pulses is indicative of the sistolic rise, an arrangement for forming the time integral of the time derivative over an interval of predetermined limit values in each of the successive blood pressure pulses as an Ila3 for the systolic rise, the interval being the time within which the lateral derivative is present ^ rbeatinuiiten reference value rises and has an order which responds in a predefined manner to the time integrals of successive blood pressure pulses with formation of an indication of the actual blood pressure, characterized in that an arrangement for the formation of a threshold value signal indicative of the magnitude is practical sch only the time derivative of a systolic rise, an arrangement for comparing the time elapse of the fluctuating component of the quantity with the threshold value signal while the time derivative is above the reference value with the formation of a control signal which gives an indication of whether or not the time derivative is above the reference value is indicative of a valid systolic rise, and has an arrangement which responds only to a verifying indication that the particular time reading above the reference value is a systolic rise for the purpose of converting the integral of the particular representation to the 809829/06 * 8 - ¹² - BATH ORIGINAL Arrangement for indicating blood pressure. * ft2>. Method of determining the blood pressure of a living being, thereby characterized in that a selectively changeable Pressure applied to the living being adjacent to a blood vessel, an amount proportional to a sum is measured that from a time-dependent fluctuating component is proportional to the amplitude of the pulsating pressure in the pressure vessel plus the selectively changeable pressure applied externally adjacent to the blood vessel converts this amount into a reproduction the time derivative of the fluctuating component of the same becomes, \ obei a part of the time derivative in each of the successive Pressure blood impulses are characteristic of the systolic rise, the time integral of the time derivative over an interval predetermined limit values in each of the successive blood pressure pulses is determined as a measure of the systolic rise, wherein the interval is the time during which the time derivative is above a predetermined reference value, a threshold signal is formed, which is characteristic of the size practically only the time derivative of a systolic rise, the The time derivative of the fluctuating component of the set is compared with the threshold value signal, while the time derivative is over the reference value lies with the formation of a control signal which gives an indication of whether or not the time derivative is above the The reference value is indicative of a valid systolic rise, selective time integrals are processed with formation an indication of the blood pressure, as well as for processing only the time interval of the time derivative renditions that give an indication that the systolic increases are valid. - 13 - 809829/0618