DE2710936A1 - DEVICE FOR THE ELECTRONIC CORRECTION OF THE COAGULATION TIME OF THE BLOOD - Google Patents

Description

The invention relates to a device for the electronic correction of the coagulation time of the Blood.

During dialysis, for example hemodialysis with artificial kidneys, the surgeon usually regulates the speeds, consequently the flow rates by means of two pumps, one of which is a heparin pump (if the coagulation time is too short) and the other protamine pump (if the coagulation time is too is short) is used to reduce the coagulation time of the blood to a desired value.

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The invention is therefore based on the object of creating a device for the electronic correction of the coagulation time of the blood according to the type mentioned at the beginning, which shows the surgeon the actual and the desired coagulation time and which automatically carries out a time correction based on the difference between these two times and, according to the sign of the difference, the speed of either the heparin pump or the protamine pump is supposed to regulate.

According to the invention, this object is achieved by a display unit for the desired coagulation time in the form of an electrical voltage (VCS) and a display unit for the measured coagulation time in the form of an electrical voltage (VOM), whereby each unit has an amplifier separation stage in front of its output, a subtractor to which the two Output signals of the display units are given and its output signal (VD) proportional to the algebraic Difference between the two output signals (VOS and VCM) of the two units is an isolating amplifier on the the generated difference signal (VD) is applied, a double unit for sign recognition of the sign of the Output signal of the isolation amplifier, with each half this unit has a transistor which is blocked for one sign and conductive for the other sign

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and its output signal to a relay with a work contact abandoned, with the transistors switched in opposite directions and a double supply unit, E.g. for pumps, each half of which is connected to the Difference signal (VD) is fed, each half having an amplifier, each with a pre-adjustable Bias is provided and the supplied output signal of each half, e.g. towards the motor of one of the pumps, either is a constant function of said bias when the working contact is open, or a puncture of the called bias voltage and the difference signal (VD) is when the Arbeltkontakt is closed.

In the inventive device for electronic Correction of the coagulation time of the blood, according to the present invention, the display unit can display the measured coagulation time replaced by an automatic device that generates the electrical voltage signal (VCM) for the corrector supplies.

Further advantageous refinements of the invention are characterized in the subclaims.

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The invention has the salient advantage that with it the true and the desired coagulation time of the Blood can be displayed, the device according to the invention corresponding to the preselected coagulation time this is automatically readjusted in the event of deviation. The device according to the invention can advantageously be used in dialysis or hemodialysis, artificial kidneys, and operations.

The invention particularly seeks to provide a corrector in accordance with the above arrangements, regardless of below which realization and which form: the circuits can be built up classically, printed or integrated, whereby the installations in which the device according to the invention is used are included, in particular the installations for dialysis or hemodialysis.

The invention is described in the following description with reference to an embodiment shown in the drawing explained in more detail. It shows:

Figure 1 is an electrical schematic diagram of a device for electronic correction of the Blood coagulation time and

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Figure 2 shows a detail of a circuit

with a central breaker for clearly highlighting a display which can be used as one or the other of the displays of FIG.

However, it is obvious that the drawing and the associated parts described are only intended to illustrate the Invention are given, and they are in no way limiting the same. Likewise, the numerical values and The types of components listed in the description are only given for display purposes only and because results that can be assessed satisfactorily are obtained in this way, but by no means to limit the invention.

FIG. 1 shows an electrical circuit diagram of the principle of the device for electronic correction of the coagulation time of the blood: a classic power supply unit (supply), e.g. from the 50 Hz network, supplies this corrector with plus 15 Volt (terminals + of the circuit diagram) and with minus 15 volts (Terminals - of the circuit diagram) and with 200 mA. The totality 10 of the time display of the desired coagulation includes a voltage divider 101 between the plus terminal and the Hasse a variable voltage tap 102.

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This voltage divider 101 with variable tap 102 is preferably shown in a detailed scheme according to FIG reproduced: it comprises the plus terminal of the switching

-Proschemas starting in series a ^ l / iderstand 103 for example of 82K ohms, (where the resistance value, as already said, is only given as an example) the tap 102, one Toggle switch 104 at intervals of hundreds with ten positions, with position indicator, which can be switched over using ten different resistors 105 (e.g. with 1200 ohms each), one Changeover switch 106 at intervals of ten, analogous to changeover switch 104 and with ten changeover resistors 107, which are ten times smaller than the resistors 105 (120 ohms each) and a changeover switch 108 in units of distance, analogous to the changeover switch 104 and consisting of ten switching resistors 109, which are a hundred times smaller than the resistors 105 (12 ohms each).

If one looks again at FIG. 1, the tap 102 feeds a capacitor 110 (e.g. the size of 47 nF) and with the interposition of a resistor 111 (e.g. of 470 k ohm) the input of an operational amplifier 112, its plus input or non-inverting input via the interposition of a buffer resistor 113 (e.g. from 390 k ohms) is connected to ground; the operational amplifier 112 is connected between its output and its inverting input (minus input) with a resistor 114 (e.g. of 2.2 H ohm).

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tet; the said signal YCS is at the output of the amplifier 112 at. As an example only, commercially available types under the designation SFC 2741 DC from SESCO can be used.

The whole 12 of the time display of the measured coagulation with the elements 121 to 134 is identical to the whole 10, which has just been described with its individual parts 101 to 114. The whole 12 also contains one Resistor 135 (e.g. from 4.7 k ohms) and a resistor 136 (e.g. from 15 k ohms), which are connected to terminals 1 and 5 of the Operational amplifier 132 are connected, with the other two connections of both resistors 135 and 136 brought together and shared to the minus source of the circuit diagram are placed in order to adjust the function of the assembly 12. The said signal YCM is now available at the output of the operational amplifier 132.

The entirety of the subtracter 14 comprises an operational amplifier 141; its minus or inverting input is via the interconnection of an amplifier 142 (e.g. 120 kΩ) with the signal VCS, which is derived from the Display 10 for the desired coagulation time originates; the positive or non-inverting input of the operational amplifier 141 is connected to a resistor 143 (e.g. from 120 k ohm)

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the signal VCM supplied, which from the display 12 for the measured eoagulation time comes from, in addition, this plus input is via a resistor 144 (e.g. from 12Ok Ohm) connected to ground; the operational amplifier 141 is furthermore between its output and its inverting input with a resistor 145 (e.g. of 120 k Ohm) and provided with a potentiometer 146 (e.g. of 10 k Ohm), which is connected between the outputs 1 and 5 of the operational amplifier 141, the movable tap of the Resistor 146 connected to the negative voltage supply i.it in order to stabilize the function of the subtracter 14. The said algebraic difference signal VD appears at the output of the subtracter 14.

The isolating amplifier 16 comprises an operational amplifier 161, the inverting or minus input of which is connected via the interposition of a resistor 162 (e.g. of 56 k ohms) the difference signal VD is applied, which comes from the subtracter 14; the non-inverting or Plus input of the differential amplifier 161 is via a Resistor 163 (e.g. of 56 k ohms) connected to ground; the output of the operational amplifier 161 and its minus input are connected across a capacitor 164 (e.g. 10 nF).

One half (the one from above in FIG. 1) of the double signal display unit 18 of the output signal of the isolating

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amplifier 16 comprises two resistors 181 (e.g. of 22 k ohms) and 182 (e.g. of 22 k ohms) placed between the signal and ground and centered on the anode of a Diode 183 (the cathode of which is connected to ground) and with a capacitor 184 (e.g. of 6.8 nF) and with a resistor 185 connected to the base of a PNP transistor 186 leads (e.g. BC 251B from ITT), its emitter to ground is laid, as is the capacitor 184; between the collector of transistor 186 and the negative voltage source on the one hand an optical signal transmitter 187 (e.g. a light bulb with 12 V, 40 mA) and on the other hand a relay 188 (e.g. a Reed relays of the type GB831A1 from CELDUC) switched, with a discharge diode 189 (with its Cathode to collector) and is in series with the parallel circuit of relay 188 and discharge diode 189 a resistor 190 (e.g., 470 ohms, 0.5 watts power); the relay 188 is provided with a normally open contact 191.

The mode of operation of this half double unit 18 is as follows: When the input signal (the signal at the output of the isolation amplifier 16) is positive, the diode 183 holds the base of transistor 186 to ground, whereby this is blocked: the optical signal indicator 187 gives no signal and the Contact 191 is open. If, on the other hand, the input signal is negative, the diode 183 does not matter, the basis of the Transistor 186 goes negative, causing it to saturate

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controlled or conductive: the collector assumes approximately emitter potential, i.e. it is connected to ground: the optical Signal generator 187 gives a signal and relay 188 closes its working contact 191 · The other half of double unit 18 (the one in the lower part of FIG. 1) is constructed in the same way, but with the following opposites: the diode 203 has its anode connected to ground, transistor 206 is an NPN transistor (e.g. a type BC171B) and the circuit is connected to the positive terminal + of the switchschetna. Hler is a negative input signal with no effect, whereas a positive input signal makes the transistor 206 conductive, the optical signal generator 207 thereby gives a signal and the Normally open contact 211 is closed.

The difference signal VD at the output of the subtracter 14 given a neutralization circuit 17: the open position of which makes it possible to momentarily stop the operation of the corrector so that the manual signal returns when it should be necessary or desired. The normal position of the neutralization circuit 17 is a closed position, in which case the difference signal TD is set to the both working contacts 191 and 211 abandoned, of which at Need for correction a single closed 1st (the one that corresponds to the signal VD, as out can be found in the description) and then transmits this signal VD to the double supply unit 22 of the motors

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of pumps.

One half of the double supply unit 22 (the one in the upper part of Figure t) of the motors of the pumps comprises one Operational amplifier 221; its non-inverting or The plus input is connected to the normally open contact 191 via the interconnection of a resistor 222 (e.g. 330 k Ohm) and through a resistor 223 (e.g. 180k ohms) to ground; the inverting or minus input is connected to ground via a resistor 224 (e.g. of 220 k ohms) and to the movable tap via a resistor 225 (e.g. of 220 k ohms) of a potentiometer 226 (e.g. of 4.7 kOhm) placed between the ground and a resistor 227 (e.g. of 10 kOhm) lies which latter resistor 227 is connected to the minus terminal of the circuit diagram; the output of the operational amplifier 221 and its minus input are connected to one another via a resistor 228 (e.g. of 220 k ohms). Of the The output of the operational amplifier 221 feeds the motor of the protamine pump (arrow VP).

The mode of operation of this half of the double unit 22 is as follows: in the absence of the signal via the resistor 222 (plus input of the operational amplifier 221), the supply VP of the motor of the protamine pump is only regulated by the potentiometer 226, i.e. by initial (manual) )Regulation; appears on the _contrary) a signal at the positive input of the

Operational amplifier 221, the voltage VP is above the

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mentioned regulation.

The other half of the double unit 22 (the one in the lower fell τοπ figur 1) including an operational amplifier 241 » whose pins or non-inverting input is connected to Hasse via a resistor 242 (see, for example, 100 k ohms); the inverting or minus input is in turn via two parallel connected resistors 243 (e.g. from 220 k Ohm) and 244 (see e.g. 2.2 MO Ohm) bit the normally open contact 211 and on the other hand via a resistor 245 (e.g. of 220 k Ohm) ι lit the movable pickup of a potentiometer 246 (e.g. of 4.7 k Ohm) connected between ground and a resistor 24? (e.g. of 10 k ohms), which is the latter ■ connected to the minus terminal of the circuit diagram; the output and the minus input of the operational amplifier 241 are connected to one another via a resistor 248 (e.g. 220 k ohms); the output "1" of the operational amplifier 241 is with a resistor 249 (e.g. of 5.6 k ohms) and the output "5" of the operational amplifier 241 is with a Resistor 250 (e.g. of 15 k Ohm) connected, which are brought together and their common line with the minus source of the circuit is connected to adjust the operation of the operational amplifier 241, the output of the Operational amplifier 241 feeds the motor of the heparin pump (arrow VH). You work this half of the double unit 22 is analogous to that used for the other half of the same

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Unit has been described.

The working method of the proofreader in its entirety 1st as follows. It is first assumed that, for example, the coagulation time is very short: then that indicated by the display unit 10 the desired coagulation time delivered voltage greater than that measured by the display unit 12 of the Coagulation time supplied voltage VCM. The subtracter generates a difference signal TD at its output, which is proportional to the algebraic difference YCS - VCM and which is positive. The isolation amplifier 16, which with this Signal is applied, generates a positive signal at its output, which within the double unit 18 leaves the work 8ko nt a let 191 open and the work contact 211 closes. In the double unit 22, the state of half VP does not change as a result, while half VH receives the difference signal VD; the supply voltage VH of the motor the heparin pump then rises proportionally to this said difference VF, which is precisely the aim pursued is equivalent to.

In contrast, if the coagulation time is too long, VCS is smaller than VCM; VD is negative; the isolation amplifier 16 supplies a negative signal at its output, which closes the normally open contact 191 in the double unit 18 and

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leaves the Arbeitekontalrt 211 open; Within the double supply unit 22, the state of half VH changes not, while the voltage VP rises proportionally to minus VD, which also just corresponds to the goal sought.

Such a corrector according to the present invention comprises coagulation times between 100 and 300 seconds (times like with a coagulation accelerator) and it can measure up to 999 seconds. The accuracy obtained is of the order of 5% when using resistors with an accuracy of 5 #, the accuracy obtained can be increased by using resistors with an accuracy of 1%. This corrector can be placed in a container 270 mm long, 80 mm high and 200 mm deep; the front panel of this container carries the operating buttons of the three tens switches 105, 106, 107 to display the desired times; furthermore, to display the measured times, operating buttons of the three tens inverters 125, 126, 127; furthermore the optical signal indicators 187 and 207; furthermore the operating buttons of the potentiometers 226 and 246; the switch 17; an on-off switch, and terminals for the outputs VP and VH to the motors of the pumps.

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From the foregoing description it follows that, whatever the designs and realizations of the same, that a coagulation time corrector is obtained which has important advantages, the most important of which were enumerated above and which, among other advantages, in the course of the use of devices for correcting the Coagulation time will occur in accordance with the present invention.

The subject matter of the present invention is not limited to the application for measuring the coagulation time of the blood, but can be used in a wide technical field, including design variants.

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Claims (8)

Claims Device for the electronic correction of the coagulation time of the blood, characterized by a display unit (10) the desired coagulation time in the form of an electrical voltage (VCS) and a display unit (12) the measured coagulation time in the form of an electrical voltage (VCM), with each unit has an amplifier separation stage (112, 132) in front of its output, a subtracter (14) to which the two Output signals of the display units (10,12) are given and its output signal (VD) proportional to the algebraic difference between the two output signals (VCS, VCM) of the two units is one Isolation amplifier (16) to which the generated difference signal (VD) is applied, a double unit (18) for sign recognition of the output signal of the isolation amplifier (16), each half of this unit a transistor (186, 206) which is blocking for one sign and conductive for the other sign is and the output signal is applied to a relay (188, 208) with a normally open contact (191,211), wherein the two transistors are connected in opposition, and a double supply unit, e.g. for pumps, each half of which via the interconnection of a switch (17) and one of the working contacts (191,211) 709838/0840 ORKjI (MMl. Claims is fed with the difference signal (VD), each half having an amplifier (221,241) which each is provided with a pre-adjustable bias voltage, and the output voltage signal supplied each Half, e.g. towards the motor of one of the pumps, either a constant function of the preload mentioned is (if the normally open contact is open) or a puncture of said polarization and the difference signal (VD) is (when the normally open contact is closed). 2. Apparatus according to claim 1, characterized in that the display unit (10, 12) of the desired coagulation time a potentiometric voltage divider (101, 102), which lies between the plus terminal of the supply voltage and the ground and is more movable Tap (102) is led to an operational amplifier (112). 3. Apparatus according to claim 1 or 2, characterized in that the display unit (12) of the measured coagulation time has a potentiometric voltage divider (121, 122) connected between the plus terminal of the voltage supply and the ground is and its movable tap (122) is fed to an operational amplifier (132) is. 709838/0840 Claims 4. Device according to one of the preceding claims, characterized in that each of the two potentioroetrisehen Voltage divider (101,121) from a Vorwider et and (103) and three changeover switches (105,107, 109) with ten positions each, the first toggle switch a decade of ten resistors, the second switch a decade of ten by the factor ten smaller resistors and the last switch a decade out of ten around the factor one hundred includes smaller resistors than the resistors of the first changeover switch. 5. Device according to one of the preceding claims, characterized in that instead of the potentiometry Voltage divider of the display unit of the measured coagulation time an automatic device is available is for measuring the real coagulation time. 6. Device according to one of the preceding claims, characterized in that the subtracter (14) comprises an operational amplifier (141), at whose minus input the voltage signal VCS and at whose plus input the voltage signal VCM is applied. 709838/0840 Claims 7. Device according to one of the preceding claims, characterized in that the isolating amplifier (16) an operational amplifier (161), at whose minus input the difference signal (VD) of the subtracter (14) and its plus input is connected to ground. 8. Device according to one of the preceding claims, characterized in that the double unit (18) to recognize the sign of the output signal of the isolation amplifier (16) on the one hand consists of: a bridge of two resistors (181,182) between this signal and ground, the center tap with a Diode (the cathode of which is grounded) and is connected to the base of a PNP transistor (186) whose emitter is connected to ground, and between the collector of this transistor (186) and the negative voltage supply of the Circuit diagrams of an optical signal display (187), the parallel to the relay (188) with the normally open contact (191) lies and on the other hand includes a bridge from two resistors (201,202) between the signal and the ground, the center tap with a diode (203), the anode of which is connected to ground, and the base of the NPN transistor (206), whose emitter is connected Ground is and between the collector of this transistor and the positive voltage supply of the circuit diagram 709838/0840 a second optical signal indicator (207), the parallel the second relay (208) is connected to a normally open contact (211). 9. Device according to one of the preceding claims, characterized in that the double supply unit (22), e.g. for supplying the motors of pumps, on the one hand comprises: an operational amplifier (221), which on its minus input with the adjustable bias voltage and on its plus input via the interconnection of the first working contact (191) with the Difference signal (VD) is applied, and the output of which feeds the motor of the protamine pump, and on the other hand comprises: an operational amplifier (241), on the minus input of which said controllable bias voltage and the differential signal (VD) is applied via the interconnection of the second normally open contact (211), wherein the plus input of the differential amplifier is connected to ground and the output of the same feeds the motor of the heparin pump. 709838/0840