WO1985002546A1

WO1985002546A1 - Infusion device

Info

Publication number: WO1985002546A1
Application number: PCT/CH1984/000167
Authority: WO
Inventors: Peter Michel; Peter Raemy; Heinz Suesstrunk
Original assignee: Disetronic Ag
Priority date: 1983-12-08
Filing date: 1984-10-09
Publication date: 1985-06-20
Also published as: EP0164359A1; JPS61500589A

Abstract

The piston (4) is actuated by a stepping motor (2) to deliver for example insulin by means of a syringe (1). The motor is started by a control means (5) which comprises a clock and a memory (11) wherein are stored a plurality of times forming a schedule. For example, each hour of the day is stored in a memory compartment (12). By means of a data input device (30) the doctor has the possibility of entering into each memory compartment (12) a value which sets for each hour the volume to be delivered. The control pulse rate of the stepping motor (2) delivered by the control means (5) will be modified as a function of the time proportionally to the infusion volume to be delivered. The patient can not modify the value which sets the volume but may however modify by means of two keys (40, 41) the infusion rate to decrease or increase it. However the increase is limited. The doctor may thus adapt the infusion rate to the variable needs of the patient during the day while preventing the patient from excessively increasing the infusion which could put the patient in danger.

Description

Infusion device

The invention relates to an infusion device according to the preamble of claim 1 and an input device for the device.

In the known infusion devices, the piston rod of the spray ampoule or syringe is advanced by means of a pinion which is driven by a clockwork (US Pat. No. 3,886,938) or by an electric motor which is fed by a battery and controlled by a control device (published European patent application No. 42 282). In US Pat. No. 3,886,938, the patient can control the fluid supply by switching the clockwork on and off.

The invention is based on the knowledge that the patient's need for infusion fluid, in particular insulin, changes in the course of the day depending on the personal lifestyle (higher insulin requirement after Meals, lower insulin requirements at night and during strenuous physical activity), but that it is not only tedious for the patient but can also be dangerous if he himself controls the dosage by switching the drive device on and off or controlling it according to his wishes changes.

The object of the invention is to provide an infusion device of the type mentioned in the introduction, in which the infusion rate changes in the course of the day according to a function of the time to be determined by the doctor on the basis of the individual circumstances of the patient.

The achievement of this object according to the invention is the subject of the characterizing part of claim 1.

The memory can e.g. 24 storage locations, so that a different infusion rate (number of volume units per hour) can be selected for each hour in the daily routine.

The device preferably has a connecting part for connecting an input device which is independent of it and for inputting the control values into the storage locations. The input device according to the invention for the infusion device provided with the connecting part is the subject of claim 9. The input device, which is independent of the device, is intended for the doctor and should not be given to the patient, so that only the doctor and not the patient receive the control values (and for the Embodiment of claim 5 can enter or change the maximum value). Entering or changing the control values that determine the infusion rate, which is reserved for the doctor, is indicated in particular in the case of insulin treatment for diabetics, because an excessively high infusion rate can lead to life-threatening hypoglycemia. The same purpose, namely the prevention of hypoglycemia, is served by the preferred embodiment of the device according to claim 3, which has a stop device which stops the drive device if the patient does not press one of the control buttons of the device for a certain, long period of time, for example 12 hours. This prevents insulin from being passed to a patient who has passed out, which would lead to hypoglycemia.

In order to enable the patient to change this rate within certain permissible limits despite the infusion rate specified by the doctor, the device can be equipped with a button-operated command device, by means of which the infusion rate, which is dependent on the control values, can be used for a specific period of time , can be increased or decreased by, for example, one or two hours. A diabetic can thus increase the infusion rate after a particularly rich meal and reduce the infusion rate during strenuous physical activity, for example during sports. So that the patient does not increase the infusion rates too often during a day and this creates the risk of hypoglycemia, a counter is provided in the embodiment according to claim 5, which pays the additional liquid units dispensed, preventing an increase in the infusion rate if the number of For example, within 24 hours, the additional quantity of liquid dispensed exceeds a maximum value to be determined by the doctor and expediently stored in a second memory of the device by means of the input device. An exemplary embodiment of the invention is explained in more detail below with reference to the drawing.

The single figure shows a block diagram of an infusion device with an input device that can be connected to the device.

The infusion device shown schematically in the drawing and intended for the automatic delivery of insulin has a housing which is designed for the interchangeable mounting of a spray ampoule 1 and in which a stepping motor 2 and a screw gear 3 for the advancement of the piston 4 of the spray ampoule 1 as well as a control device 5 are arranged for the control of the stepping motor 2. The gear 3 consists of a rotatably mounted driving sleeve driven by the stepper motor 2, into which a threaded rod for the advance of the plunger of the spray ampoule is inserted in a rotationally fixed but longitudinally displaceable manner. A nut sits on the threaded rod and is held in a rotationally fixed manner on the housing part adjoining the rear end of the spray ampoule. The gear and the holder of the spray ampoule are the subject of Swiss patent application No. 4 887/83. Of course, the stepper motor 2 could also have the piston 4 of the spray ampoule or a syringe in the manner described in US Pat. No. 3,886,938 or the Europ. Drive patent application No. 42 282 known manner in the manner of a conventional rack and pinion drive. The control circuit 7 of the stepping motor 5 is fed by a battery 8 provided exclusively for the motor drive. A second battery, not shown, is provided in the device for the control device 5 and the circuit parts connected to it. The control pulses for the control circuit 7 are generated by the control circuit 5 at a clock frequency which, in the manner described below, according to the time of a clock 10 (timer) as a function of control values and stored in a first memory 11 at every hour of the day any commands from a command generator 14 is changed.

By means of a measuring mechanism 16 and a counter 17, the control device 5 periodically monitors the number of steps carried out by the motor 2 in the relevant period. The measuring mechanism 16 consists of an aluminum disk which is seated on the output shaft of the stepping motor 2 and is provided with a ring of light / dark fields and a laser diode / photodiode unit which emits light pulses and detects the light pulses reflected by the bright fields of the disk. The counter 17 counts the light pulses detected by the diode unit and the control device 5 periodically sets the counter 17 to 0 and at the end of each period compares the number of control pulses emitted by it in this period with the counter reading and gives a pulse sequence to a buzzer if it does not match 19. For this purpose, the control device 5 has a counter (not shown) which counts the control pulses emitted by it and a comparator (not shown) which compares the counter reading of the counter 17 with that of the counter for the control pulses and switches the pulse train on emits the signal triggering the buzzer 19 when the difference in the counter readings passes agreed tolerance value exceeds. The intermittent buzzer signal indicates to the patient that the fluid supply is disrupted, for example due to a catheter occlusion or a blockage of the needle.

The memory 11 has a memory location 12 for every hour of the day, that is a total of 24 memory locations. In these storage locations 12 control values are stored which indicate the number of volume units to be dispensed in the respective hour. The control device 5 also has a second, third and fourth memory 22, 23, 24, each with one memory location. The memory 22 is used to store a maximum value which specifies the maximum number of volume units (VE), which may also be issued during a whole day without any risk to the patient by commands from the command generator 14. The memory 23 stores in each case a value emitted by the command transmitter 14, which indicates the number of volume units which are to be additionally dispensed within the hour following the actuation of the command transmitter 14. Correspondingly, the memory 24 stores in each case a value indicating the number of volume units by which the liquid volume to be dispensed within the hour after the one or the two decisive control values is to be reduced.

To enter the control values in the memory 11 and the maximum value in the memory 22, an input device 30 intended for the doctor is provided, which can be connected to an interface 32 of the control device 5 by means of a plug connector 31. The input device 30 has one corresponding to the memory 11 Memory 33 with also 24 memory locations 34, into which the control values for the 24 hours can be entered using four keys 35. A screen 36 shows a bar diagram of the control values (number of volume units VE) stored in the storage locations 34 as a function of time. (The length of the strings that are assigned to one hour of the day is proportional to the respective control values.) With the left and right keys 35, which are identified by an arrow pointing left and right, the storage location or time is selected , with the upper and lower keys, which are indicated by an arrow pointing upwards or downwards, the control value stored in the respectively selected storage location is incremented or decremented. The maximum value to be stored in the second memory 22 is entered into a second memory 38 of the input device 30 by means of a keyboard 37 and displayed by a digital display 39. After entering and checking the control values and the maximum value, the doctor connects the input device 30 to the device and the contents of the memories 33 and 38 are transferred to the memories 11 and 22 of the device. It is essential that the control values and the maximum value can only be entered by means of the input device 30 in the possession of the doctor and the patient has no possibility of changing these values by means of the keys 40, 41 provided for him on the device.

The keys 40, 41 are used to actuate a start-stop unit 43 and the command device 14. The start-stop unit 43 issues a start or stop signal to the control device 5 if the key 40 or the key 41 is longer than Is pressed continuously for 4 seconds. Simultaneously with the start or stop signal the unit 43 sends a reset signal to the command generator 14, which stores 23 and 24 on the basis of this signal

0 sets. When the key 40 is pressed briefly (less than 4 seconds), the command generator 14 sets both memories 23 and 24 to 0 and generates a 30 second pulse, during which time it presses the memory 23 each time the key 40 is pressed and each time the key is pressed 41 increments the memory 24, ie increases the stored value by 1. The value stored in the memory 23 and corresponding to the number of actuations of the key 40 indicates the number of additional volume units (VE) to be dispensed; accordingly, the value stored in the memory 24 by actuating the key 41 indicates the desired reduction in liquid delivery. The value that can be entered into the memory 23 is limited in that the command generator 14 has a counter (not shown) and only increments the memory 23 if the counter reading does not exceed a certain maximum value. At the end of the 30 second pulse, the command generator 14 issues a command to the control device 5 for reading the memories 12, 23, 24 and for calculating the clock frequency.

Each time the button 40 is actuated, two time counters 45, 46 connected to the clock 10 and serving as transit time meters are set to 0. (If the time counters 45, 46 are designed as a down counter, they will open

1 or 12 hours.) After an hour has elapsed, the time counter 45 sends a reset signal to the command generator 14, which then clears the memories 23, 24 and again issues a read and arithmetic command to the control device 5. After 12 hours, the time counter 46 sends a signal to a stop unit 47, as a result of which the latter sends a stop signal to the control device 5. The tax prep Direction 5 then interrupts the delivery of the control pulses and triggers a continuous warning signal from the buzzer 19 until the starting unit 43 triggers the renewed delivery of control pulses by continuously pressing the button 40 for at least 4 seconds. The time counter 46 and the stop unit 47 prevent insulin from being passed to a patient who has passed out for a longer period of time, which could lead to hypoglycemia. In order to avoid hypoglycemia due to an increased insulin delivery by the patient, for example hourly by actuating the command device 14, a counter 48 is provided, which is set to 0 by the clock 10 at midnight and which is reset by the control device 5 due to the respective in memory 23 stored value counts additional delivered volume units. A comparator 49 compares the counter reading of the counter 48 with the maximum value stored in the second memory 22 and sends a signal to the command generator 14 when the counter reading reaches the maximum value. The command generator 14 then clears the memory 23. The clear command is retained regardless of an actuation of the key 40 until the counter 48 is set to 0 by the clock 10 (at midnight).

A display 50 shows the patient the contents of the memories 23 and 24. The display 50 also expediently shows the difference between the content of the memory 22 and the status of the counter 48, i.e. the maximum volume of liquid that can be dispensed on each day.

The control device 5 calculates the clock frequency of the control pulses by means of an arithmetic unit 51 at the beginning of each hour indicated by the clock 10 by an hourly signal and with each command of the command donor 14. It reads the content of the memory location 12 assigned to the relevant hour as well as the memories 23 and 24, adds the content of the memory location 12 and the memory 23 and subtracts the content of the memory 24 from the sum. The multiplied amount is multiplied by a , stored in a read-only memory (not shown), which indicates the number of steps or the fraction of a step that the motor has to perform 2 per second, so that a total volume unit is dispensed for one hour. The product is the clock frequency with which the control device 5 generates the control pulses for the control circuit 7 until an hourly signal from the clock 10 or a command from the command generator 14 triggers a new calculation of the clock frequency.

The control device 5 further uses the arithmetic unit 51 to calculate the time interval within which an additional volume unit is dispensed by dividing one hour by the value stored in the memory 23, and periodically gives a pulse to the counter 48 after this time interval has elapsed until a command from the command generator 14 triggers a new calculation of the clock frequency and thus also of the time interval.

In order for the patient to feel the effectiveness of a command to increase the infusion rate as quickly as possible, the command generator 14 can set the value in the third memory 23 higher during a first time segment of, for example, 15 minutes than during the remaining time until the memory 23 is deleted as a result of the reset. Signals of the counter 45. The command generator 14 can be a buffer for storing the value selected by pressing the key 40 several times and have an arithmetic unit and multiply the value stored in the buffer for the first time period, for example by a factor of 4/3 and for the remaining time period by a factor of 8/9. In this case, the command generator 14 first stores the value multiplied by the factor 4/3 in the memory 23 and after 15 minutes (indicated by the time counter 45) the value multiplied by the factor 8/9, at the same time issuing a command for the recalculation the clock frequency there. As a result, 1/3 of the additional fluid volume desired by the patient is dispensed during the first 15 minutes and 2/3 during the remaining 45 minutes.

In a variant of the infusion device, not shown, a 4-bit 1-chip microprocessor of the type NEC 7503 with a 4K x 8 ROM program memory and a 224 x 4 RAM read / write memory is provided for controlling the stepping motor 2. A 16 x 8 EEPROM memory is connected to the microprocessor for storing the data that can be input by means of the input device 30 (4 bits are available for the 24 control values and the maximum value). The input-output channels of the processor are linked to the control circuit 7, the measuring mechanism 16, the interface 32, the keys 40, 41, the buzzer 19 and an LCD display corresponding to the display 50. The program written in the ROM program memory in a mask-programmed manner is designed such that the processor essentially carries out the switching functions described above in connection with the control device 5, the command device 14, the clock 10 and the counters 17, 45, 46, 48. The following will be therefore only the deviating or additional steps of the program are explained.

The processor, like the control device 5, is powered by a second battery that is provided for the control 7 in addition to the battery 8. It has a circuit which, when the second battery is replaced or a voltage drop, ensures that the processor switches to a standby mode in which the memories are supplied with an auxiliary voltage from the battery 8, so that the contents of the memory cells are retained . When the second battery is inserted, the processor goes into a hold or wait state (stop) in which no control pulses are given to the control circuit 7. By pressing the button 40 for at least 4 seconds, the processor is set to the operating state (Run), in which it gives the control circuit 7 control pulses, the clock frequency of which is set in proportion to the control value stored at the respective time (the clock present in the microprocessor).

A subroutine is provided for increasing or decreasing the infusion rate (the clock frequency of the control pulses), which is called up in the processor's operating state (Run) by briefly (less than 4 seconds) pressing key 41. The command to increase or decrease the clock frequency is then given by pressing the key 40 or 41 several times, the subroutine being terminated with a return command ten seconds after the last key actuation. (So only button presses that are consecutive at intervals of less than ten seconds are taken into account.) Depending on the number of times the button 40 or 41 is pressed, various data are written into the RAM memory by means of the subroutine, which, after returning to the main program, do the following:

By pressing the key 40 n times, the value n-1 is stored in a first memory location of the RAM, which indicates the number of volume units which are additionally to be dispensed within one hour. The value is limited to 15; when button 40 is pressed for the seventeenth time, the value is reset to 0. The processor has a counter that is started as a timer with the return command of the subroutine. The main program periodically calls up the value stored in the first memory location of the RAM at short time intervals (e.g. every minute) and increases the clock frequency so that in addition to the liquid volume, which is to be output due to the control values stored in the EEPROM based on the times, the first A quarter of an hour after the return order, and during the subsequent three-quarter hour the remaining two thirds of the additional volume of liquid indicated by the retrieved value. After the hour, the first memory location of the RAM is reset to 0.

Pressing the key 41 stores the value 1 (pressing once), 2/3 (pressing twice), 1/3 (pressing three times) or 0 (pressing four times) in a second memory location of the RAM memory. When the button is pressed a fifth time, the value 1 is saved again. The main program also periodically retrieves the value stored in the second memory location of the RAM and multiplies it based on the the clock frequency, which is the relevant control value stored in the EEPROM, with the retrieved value, so that the clock frequency is maintained or reduced to 2/3, 1/3 or 0 depending on the retrieved value. The reduction is maintained for two hours, the reduced clock frequency changing according to the time in accordance with the control values. After the two hours, the second memory location is set to 1. It should also be noted that when the key 40 is pressed, the second memory location is set to 1 and when the key 41 is pressed, the first memory location is set to 0, so that values for increasing and decreasing the infusion rate cannot be stored at the same time.

To enter the control values and the maximum value by means of the input device 30 into the EEPROM, the processor is to be put into the stop or waiting state (stop), which is done in the operating state (run) by pressing the key 40 for longer than 4 seconds.

The LCD display of the processor shows the following: the time, the total liquid supply still available in the spray ampoule 1, the reduction in the infusion rate (3/3, 2/3, 1/3, 0) selected by means of the key 41 the number of additional volume units (0, 1, 2, ..., 15) selected by means of the key 41 and the difference between the latter and the additional number of volume units already output therefrom.

The two embodiments of the invention described above are intended for insulin delivery. Of course, the device according to the invention can also be used for the infusion of other liquids can be used, and if necessary the reduction in the infusion rate can also be limited, in a manner corresponding to that in the above exemplary embodiments the increase in the infusion rate is limited because of the risk of hypoglycemia.

Claims

1. Infusion device for automatically dispensing liquids from a spray ampoule (1) or syringe, in particular insulin, with a drive device (2) for advancing the plunger (4) of the spray ampoule (1) or syringe and a control device (5) for the Control of the drive device, characterized in that the control device (5) has a clock (10) and a memory (11) with memory locations (12) assigned to specific times, in each of which a control value is to be stored, which is the number of times between them volume units assigned and to be output to the next time, and that the control device (5) controls the drive speed of the drive device (2) according to the time depending on the control values stored in the storage locations (12).

2. Apparatus according to claim 1, characterized in that the drive device has a piston (4) by means of a gear (3) driving stepper motor (2) controlled by control pulses from the control device (5), and the control device (5) has the clock frequency of Control pulses according to the time proportional to the control values stored in the memory locations (12).

3. Apparatus according to claim 1 or 2, characterized by a stop device (47) which has a runtime meter (46) connected to an operating button (40) of the device and reset each time the button is pressed, and the drive device (2) stops when the runtime meter (46) specified duration exceeds a predetermined maximum.

4. Device according to one of claims 1 to 3, characterized by a by means of one or more keys (40, 41) operable command transmitter (14) through which the drive speed of the drive device (2) or clock frequency depending on the time and the control values Control pulses can be increased and / or reduced during a certain period of time.

5. Apparatus according to claim 4, characterized by a second memory (22) in which a maximum value is to be stored, which indicates the maximum number of volume units, each of which during a period of e.g. 24 hours without danger to the patient may additionally be issued by commands from the commanding party (14), and a counter (48) which counts the additional volume units given by commands from the commanding party (14) during the period and at the end of the period for the Counting is reset to 0 in the subsequent period, as well as a comparator (49) which compares the counter reading of the counter (48) with the maximum value stored in the second memory (22) and an increase in the drive speed of the drive device or the clock frequency of the control pulses emits a blocking signal by the command generator (14) when the sum reaches the maximum value.

6. Device according to claims 2, 4 and 5, characterized by a third memory (23) for storing an additional value given by the command generator (14) to increase the clock frequency, which indicates the number of additional volume units to be delivered, and an arithmetic unit ( 51) the tax Device (-5) for the calculation of the clock frequency, which occurs in the third memory (23) and at each of the specific times and with each command of the commanding party (14) or periodically in short time intervals compared to the specific time period and the time differences between the specific times the value stored in the memory location (12) of the first memory (11) assigned to the respective time added and the sum multiplied by a constant factor, the product being the clock frequency.

7. Apparatus according to claim 6, characterized in that the command generator (14) has a time-of-flight meter (45) which is reset when an additional value is entered in the third memory (23) and after the expiry of a first period of the determined period of time the additional value in the third memory ( 23) reduced to a certain fraction and at the end of the certain time period deletes the third memory (23).

8. Device according to one of claims 1 to 7, characterized by a connecting part (31) for connecting an input device (30) for entering the control values in the memory locations (12) of the first memory (11) or the maximum value in the second memory (22).

9. Input device for the infusion device according to claim 8, characterized by a plug-in part (31) that can be connected to the connection part (31) of the device and a keyboard (35, 37) for the selection of the individual storage locations (12) of the first memory (11 ) control values to be entered or the maximum value to be entered into the second memory (22).

10. The device according to claim 9, characterized by a display (36), which is a bar diagram of the selected by means of the keyboard (35) in the memory locations (12) of the first memory (11) of the connected device or an intermediate memory (33) of the device stored control values in the sequence of the assigned times.