DE3228958A1 - Method and device for recording and storing curves of forced expiration - Google Patents

Abstract

In the method according to the invention, a constant volume increment is determined; in the course of expiration, those periods are measured and stored which are necessary to change the volume of the expired air by the given increment; furthermore, a count is kept of how frequently the volume of the expired air changes by the given increment during expiration, after which the periods required to reach the previously determined volume increment are compared in sequence with a prescribed period; as soon as the period required to reach the volume increment becomes longer than the given period, the recording of the expiration curve is terminated. In the proposed device, the respiration meter is connected via a measuring transducer to a computing unit (16) which is provided with a display (17) and a supply unit (19). The measuring transducer contains mechanically attached, periodically repeating elements which are arranged at spaces of equal distances corresponding to a given volume increment; the computing unit (16) contains a microprocessor which has a memory and whose interrupt input is connected via a signal convertor to the output of the measuring transducer. <IMAGE>

Description

Procedure and facility for recording and storage

Securing curves of forced exhalation The invention relates to a Method and device for recording and storing curves forced Exhalation, especially during screening.

In spirography, the investigation of forced exhalation is used especially to separate healthy and sick groups, but such tests are also widely used for other diagnostic examinations.

In the course of such examinations one leads more intensively after it has been carried out Inhalation (with the largest possible volume) forced exhalation (with as much great power and speed). For the doctor, the curve delivers the perfect one Volume (change) - time the most important information. To characterize the Forced exhalation (forced vital capacity) curve will mostly be the final value or the steepness of the significant points agreed upon or through the selected Points drawn tangents and secants are used. The characterization of the The parameters used in the curve are mostly taken from the on the chart paper existing expirogram determined graphically.

Several companies provide those suitable for taking the expirogram (designed in a closed system) respiratory meters, including the Hungarian company Medicor Werke (known under the name Eutest). The graphic Evaluation is quite laborious and time consuming; so is lately in the respiratory meter also built in a target computer unit. The first such apparatus was made by the Dutch company Mijnhardt under the brand name Vicatest-2. In this apparatus, a microprocessor data processing unit calculates the necessary Parameter.

The breathing meter, which is designed in a closed system, is the displacement of the system measuring the volume or its change (the bell) relatively large (about 300 mm) and takes place at a highly variable speed instead of. This means that the entire curve is stored in the memory of the arithmetic unit the (forced) exhalation must be stored formally.

The conventional solution exists (also with the Vicatest-2 apparatus of the Company Mijnhardt) from converting the displacement of the bell into an analog one electrical signal, from digitizing the signal with an A / D converter and from the input of the digital signal series. The frequency of sampling must be make sure none of the information is lost. (From the saved Data, the original curve should be able to be reconstructed true to form). That means in the case of spirography, sampling with a frequency of more than 16 / s.

These solutions are used to specify the speed-time function generally uses a method in the sense of which the values of the functions in given times (generally in equal time periods). In these cases the independent variable is time, and the dependent variable the speed chosen.

This classic solution appears from a metrological point of view by no means considered to be the best. At a given sampling frequency (Time division) fall namely on the steep (particularly changeable) section only relatively few points on the curve; a loss of information can occur here, which may have to be compensated for by increasing the sampling frequency; as a result, they are now on the flatter (less changing) section of the curve unnecessarily many points containing no information are dropped in such a way that that the transducer only measures the noise of the system. The many superfluous Points unnecessarily drain both memory and processing capacity.

The aim of the invention is a method and a device for Application in spirographs (expirographs) to develop with the known Solutions compared significantly easier and substantial in terms of the circuits is cheaper.

The invention is based on the knowledge that from the standpoint Metrology is considered much more beneficial when the roles of independent and of the dependent variables are interchanged, and e.g. in the present Case, the length of the period of time assigned to a certain increase in volume (e.g. 50 ml) is measured.

In this case, the steep sections of the curve - with the compared to previous situation - much fewer points in memory will be superfluous Values (points) (not containing information) not entered, all information the saved points is valuable. The sampling with constant increase fits better at the curve shape; at high growth rates the equivalent increases Sampling frequency increases, with a slight increase in speed the frequency increases away. That way the information doesn't even go on the significantly changing one Sections are lost, and even longer changes can lead to redundant points be avoided.

The prerequisite for taking a sample with a constant increment is present in a periodic arrangement (with equal pitch), which when changing (from of the same size) the desired variable to be measured is an electrical signal releases, furthermore in an arrangement that shows the time interval between the to measure the signals mentioned and the length of the time interval between them is capable.

The length of the time intervals between those possible from the above Realization originating signals can also contain a microprocessor with a Circuit arrangement can be measured in such a way that the signals after suitable forming be fed to the interrupt input of a microprocessor. The microprocessor measures (with an internal program) and stores it in its writable memory the time elapsed between the individual interruptions in sequence.

the time measurement takes place within the processor with the implementation a "timing cycle" instead. The lengths of the commands occurring here - like the Microprocessor commands in general - are timed; the exact This enables time measurement. After this period of time has elapsed the register grows, the increment is a double byte (the content increases by one unit). The arrival of the interrupt sets up the processor to the program part of the data memory which is responsible for correcting the content of the Timing register and takes care of the storage; at the same time, the increase in the Contents of the interrupt counter register made by one. Subsequent runs the processor returns to the timing routine. The steps outlined above will be Repeatedly until signals arrive at the interrupt input or any predetermined boundary condition is met. (In the case of an expirograph, the boundary condition fulfilled by the fact that between successive interrupts (interrupts) more than 3 seconds pass).

In the course of the method according to the invention, a permanent one in advance Increase in volume determined; during exhalation, those periods of time are measured and saved the changes in the volume of exhaled air to the given Increments are required; at the same time it is counted how often the volume of the exhaled air increased by the given increment during exhalation; further become the time spans required to reach the specified volume increment compared in turn with a given duration, and when the to reach the time required for the volume increment is longer than the specified time, the recording of the exhalation curve is ended.

In the proposed device, the respiratory meter is about one Transducer connected to a computing unit with a feed unit and is provided with an indicator. The transducer contains mechanically attached, self periodically repeating elements that correspond to the given volume increment, are arranged at equal intervals existing pitches; also contains the arithmetic unit has a microprocessor provided with a memory, its interrupt input is connected to the output of the transducer via a signal converter.

With regard to the fact that in the expirograph the measuring (moving) Bell only performs a one-way shift, there is no need to take and Storage of the volume measurement, as it is based on the running number on the sensing element forming signal can be calculated.

In order to be able to save the expirogram correctly, the measurement and taking those of the same amount required for the successive increments Times indispensable.

In this case the inversion of the function appears in the memory V / t (volume-time), but from the standpoint of further processing with the original Function is identical.

The invention is based on an advantageous exemplary embodiment below explained in more detail with reference to the drawings.

In the drawings, Fig. 1 shows a scheme of the invention Device, Fig. 2 is a block diagram of the timer and memory program, Fig. 3 the keyboard, and FIG. 4 the protection circuit of the printer.

During the investigation, the system of the establishment and the Respiratory organs of the patient a uniform closed gas space. The investigation extends only to the duration of a (forced) exhalation.

The basic structure is shown in FIG. The patient will via a single-use (or sterilizable) Mouthpiece 1 provided ribbed hose 2 connected to the apparatus.

The connector 22 with a serving to drain off the condensation water provided breathing meter of the apparatus works on the piston principle - like it from Figure 1 can be seen - with the airtight seal between one with one Moving metal cylinder 21 provided with a push rod 7 and a housing 5 the breathing meter with the help of a thin-walled rubber cylinder 4 ensured will. The air blown into the apparatus via a valve 3 shifts moving metal cylinder 21 from its basic position, at the same time it sets one attached to the push rod 7 or to a pen 12, the displacement Perceptual element 6 via a computing unit to forward the diagram paper Motor 13 in motion. The arm holding the pen 12 is stationary on the moving metal cylinder 21 and moves in a in the housing 5 formed vertical gap. Draws under the action of the blown air the pen 12, which moves with the metal cylinder 21, the expirogram on, which is connected to the motor 13 and an accompanying paper feed role 15 animated scribed writing with a suitable two-dimensional scale (Volume-Time) provided graph paper 14 on. The stationary part of the transducer of the apparatus contains a mechanically attached, periodically repeating An element such as one arranged in a film holder 8 is fixed on a film optical column row 9 with the same division (from light and dark bands of same width), in front of which is the one on the moving part of the breathing meter attached pen 12 together from an infrared light source 10 and an infrared sensor 11 (a phototransistor) moves the existing sensor element, which forms the movable part of the transducer. Under the action of the movement before the row of columns 9 arise on the sensor element voltage pulses that are from the Output of the transducer via a signal converter to the interrupt input of a Microprocessor of a computing unit 16 are fed. The inner program of the The microprocessor measures the time elapsed between each interruption and stores them in sequence in a writable memory. Furthermore the arithmetic unit fulfills the following tasks: The unit observes the length of the individual time intervals, and should exceed this 3 sec., i.e. if within 3 sec. No pulse has arrived at the interrupt input, consider it the data acquisition is finished and begins to calculate the required parameters. The unit continues to watch the keyboard used to search for the parameter and writes the parameter searched for by pressing the corresponding pushbutton on an indicator 17. In addition, it supplies the control of a pressure connection sleeve band 20 connected Thermal printer and prepares over all measured Parameters a printed record. The computing unit 16 is also with a Feed unit 19 connected.

The internal timing program of the microprocessor is related described in detail with FIG. Preceding the arrival of the first interruption the microprocessor carries out the necessary initializations.

Then the microprocessor allows the interruption and gets into a "Halt State". In this dynamic standby state generally reaches him the first interruption (possibly RESET, which causes the processor to start a new measurement being prepared). This way the time of the first increment (50 ml) will not measured, which, by the way, would be impossible in principle, since the (initializing) Program of the processor starting RESET signal and the beginning of the measurement (exhalation) are not synchronized. This missing first information is implied by the second. The microprocessor measures the time elapsed between the individual interruptions as part of a. "Timing Cycle". The length of those occurring within this cycle Commands (like microprocessor commands in general) are strictly timed. The time measurement is made possible by this. The processor performs the in the "Zeitmeßzykius" commands contained exactly within 50 #sec. Meanwhile, an increments (Inner) register with a length of one double byte. The arrival of a new interruption directs the processor to the data memory program part responsible for the correction of the content of the timing register, for storage and for the increment of the Contents of an interrupt counter register provides for one. Subsequent leads the microprocessor repeats a "timing cycle" from which only one new interruption occurs ~ tear him out "can.

The steps described above are repeated until between expire more than 3 seconds after two interruptions have occurred. Now consider the Microprocessor stops breathing and forbids receiving further (delayed) Interrupts and begins to evaluate the data.

At the end of the measurement process there are partial times of double bytes in the memory, measured in 50 ßsec units, all available in a volume increment of 50 ml belong. The interrupt counter compartment contains the number of all accepted Interruptions, i.e. the total exhaled volume value in units of 50 ml.

The printer following the pressure connection sleeve band is useful with a functional and numeric keypad for entering patient data (age, Body weight, height, gender). The arithmetic unit forms from this information 16 the statistical average values (normal values) and thus compares the measured values Parameter.

The basic circuit diagram of a row of pushbuttons searching for parameters 18 and a push-button keyboard is shown in FIG. One with the arithmetic unit Address bus A0 that establishes the connection. . . A3 and a data bus Dg D3 adjoin each other in a matrix arrangement. In the matrix nodes the pushbuttons N are available with a simple closing contact.

The diodes separate the matrix from the address bus AO ~~~ A3 (the one Contact of the pushbuttons), while the remaining contacts are tri-state buffers BO ~~~ B3 join the data bus Do ... D3.

The inputs of the buffers Bo0 * B3 are with resistors R0. . R3 on brought the H level to the load on the data bus D0. . . Avoid D3 even then to be able to, if this does not fulfill a keyboard function.

Buffer B10 ... B13 10 # .B13 of the address bus A0 ~~~ A3 only realize the bus driving function of the system.

If a keyboard reading signal TR is issued, the one just depressed conducts Push button N any "O" level sent on address bus Aov * A3 onto the data bus D0 ... D3 via the buffer B0 ... B3, the level being passed on which has been approved by the keyboard read signal TR of the arithmetic unit 16.

On the address bus A0 ... A3 (line directly connected to the keyboard) an H level is present with the exception of an address bus.

The continuous query takes place in such a way that the processor always sends the level "O" to a different address bus, after which the signals of the Data bus D0 ... D3 to be admitted. On the data bus D0 ... D3 is due to the Resistors R0 R0 ... R3 have an H level, the data bus is an exception the just depressed push button N, which goes to the level L when the depressed Push button N changes the "O" level appearing on the address bus to the corresponding one Data bus transmits. From which data bus and under which address the level L appears, the pressed pushbutton N can be identified.

On the (in a more strict sense) taken data bus A0 ... A3 will the address formed from the power of the number 2; this can easily be done with a program to be generated. If two or more pushbuttons are pressed at the same time, the simultaneous pressing is filtered by the program check, i.e. exclusively A push button is only accepted as pressed if during three (complete) a match can be determined for subsequent queries.

The particular advantage of the circuit arrangement described shows The fact that not even the use of numerous pushbuttons does the circuitry complicated, i.e. the number of hardware elements does not increase by leaps and bounds.

In the thermal pressure unit adjoining the pressure connection sleeve band 20 there is a new type of protection of the pressure segments against overloading (power limitation).

The pressure segments must be for a specified time and with a certain electrical power can be heated.

In order to be able to protect the segments, it must be ensured that over the duration of the function and an electrical one within the set cool-down period Performance cannot get to the segments at all - not even when damaged of the control circuit - and during the normal operating period, i.e. during the Pressure, only the set (limited) power gets there.

The electrical diagram of the proposed new solution is in shown in FIG.

The protection circuit is in the same module as one the supply unit 41 connected to the mains voltage UIN.

This solution is much more beneficial than if the protection circuit would be assembled with a power control unit. This advantage can continue be increased if the printer (or the one demanding a power control Means) is arranged on several cards, since in this case also the print head is protected if a card is withdrawn as a result of negligence, which leads to malfunction.

There is also the option of using the logic protection circuit a feed unit that is independent of the feed resistance of the system to be protected to provide; in this way the operational safety can be increased. In the ungrounded A small-value resistor R5 is provided to branch off the feed unit 41. Its value can be chosen so that a suitable comparison voltage (5-10 mV) arises. For a comparator K, the reference voltage is from one in front of the resistor R5 arranged, generated from resistors Rq, R5 voltage divider. Opposite to the output voltage UOUT can be the desired difference of 5-10 mV with the divider can be adjusted, whereby the resultant from the fluctuation of the supply voltage any uncertainties in the comparison can be eliminated. When heating up of the segments, the voltage applied to the resistor RS exceeds the set voltage Value. In such a case, the comparator flips over and sets a monostable Multivibrator (with the possibility of repeated starting) in operation, to be on the safe side, set to a higher time control (larger pulse width) is than the calorific value of the segment permitted by the control electronics. The exit of the monostable multivibrator 42 connects to an AND gate 44. Also the The initial state of the comparator K reaches through an inverter 43 here. A certain delay time must be ensured during the inversion which must be longer than the transit time of the monostable multivibrator 42. At using logical elements of different types, this value can be different be. With a normal function, the signal at the output of the AND gate changes 44 not. If the control electronics malfunction, however, appears the high level at the output, and in view of the fact that the control (heating) the state indicating the segment lasts longer than the timing time of the monostable Multivibrator 42, the signal appearing at the output of AND gate 44 arrives to the ignition electrode of the thyristor T, which in the switched-on state between the resistor R5 and the feed unit arranged fuse B can burn out. The input of the AND gate 44 is followed by the RESET signal of the arithmetic unit 16, the function for the duration of the processing of the switch-on transients of the circuit is prohibited. For the sake of order, it should be noted that the Output signal of the AND gate 44 in addition to those mentioned above also to fulfill other Functions, e.g. for error display on the front panel or for error display for the control logic.

The feed unit must have a structure in which the fuse B and a thyristor T immediately follow the high-quality buffer capacitor. Of the Stabilizer circuit (if any) is after the fuse or the thyristor T in the non-earthed junction. This measure does not affect the essence of the function, but it prevents the from going under Stabilizer circuits as a result of a high (short-circuit) current.

The circuit arrangement according to the invention represents a fully-fledged solution for the protection task described above, since they, if from any Reason (during or outside of the printing process) a heating current that lasted too long would get to the segments, the segments by burning out the fuse B protects. Another advantage is that the protective function with right a few circuit elements can be implemented easily and cheaply.

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Claims (4)

Method and device for recording and storing curves forced exhalation PATENT CLAIMS: Method for absorbing and storing Curves of forced exhalation, in that a constant Volume increment is determined in advance, in the course of exhalation those periods of time Measured and stored, the changes in the volume of exhaled Air around the given increment are required, furthermore it is counted as often the volume of air exhaled during exhalation is around the given Increment changes, whereupon it takes to reach the predetermined volume increment required time periods are compared sequentially with a predetermined period and the recording of the exhalation curve is terminated as soon as it is reached of the volume increment becomes longer than the given period will. 2. Device for performing the method according to claim 1, in which a respiratory meter is connected to a computer unit via a transducer, which is provided with a feed unit and an indicator, thereby g e k e n n notes that the transducer was mechanically attached, repeating periodically Contains elements that correspond to the divisions in a given volume increment are arranged at equal intervals, and that the arithmetic unit (16) has one contains a memory provided microprocessor whose interrupt input is connected to the output of the transducer via a signal converter. 3. Device according to claim 2, characterized in that g e k e n n z e i c h n e t, that a parameter-seeking print is sent to the arithmetic unit (16) #: # row of rows (18) and a printer provided with a keyboard is connected via a pressure connection sleeve band (20) are that the parameter-searching push button row (18) and the keyboard of the printer are designed such that the connection to the computing unit (16) is established Bringing address bus (A0.. .A3) and data bus (Do *** D3) form a matrix arrangement, in the nodes of which pushbuttons (N) with closing contacts are arranged, whose a contact via an isolating diode (DoXD3) with the address bus (A0 .. .A3) and their other contact on the one hand via a three-state buffer (B0 ... B3), on the other hand is connected to the supply voltage source via a resistor (R0.. .R3), and that the keyboard reading input signal (TR) of the buffer (B0 .. .B3) to the arithmetic unit (16) is connected. 4. Device according to claim 3, characterized in that g e k e n n z e i c h n e t that it is connected to a supply voltage unit (41) via a printer protection circuit connected that in the protective circuit a series-connected fuse (B) and a resistor (R5) are included that between the fuse (B) and the in Series connected resistor (Rs) a parallel made from a connected thyristor (T) or a voltage divider composed of resistors (R4, R5) is connected to its division point and its in the direction of the output of the series-connected Resistance (Rs) lying point connected to the inputs of a comparator (K) are, while the output of the comparator (K) on the one hand via a monostable Multivibrator (42), on the other hand via an inverter (43) to the inputs of an AND gate (44) is connected, and that another input (RESET) of the AND gate (44) with the computing unit (16) is connected, the output of the AND gate (44) to the Ignition electrode of the thyristor (T) is connected.