CH685461B5 - liquid substances therapeutic infusion sets and portable device comprising such a device. - Google Patents

Description

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Description

In the treatment of certain diseases, it may be useful to be able to administer liquid therapeutic substances over long periods ranging from 1 to several days.

The best known system is the "drip", comprising a simple constriction to adjust the flow between the tank and the outlet pipe. This passive and imprecise system can only be used in very general applications.

Oven to overcome these faults, it has appeared for ten years motorized systems comprising a pump interposed between the tank and the system outlet pipe. The pump flow can be regulated, or even programmed precisely by suitable electronic control means. These pumps are generally of the “peristatic” type and include a system of rollers carrying the desired substance by crushing a pipe in which it circulates. This system gives periodic variations in flow and has a very poor energy efficiency, but has the advantage that the liquid is never in contact with external elements which could alter it.

Some of these systems are portable and have their own power source, allowing the patient to move with minimal constraints. This represents an important advantage, especially for long-term treatments outside the hospital environment. However, it goes without saying that the smaller the system, the lower the power available at the pump, and the latter can therefore be blocked relatively easily, especially if the efficiency is low.

Another known system does not use a pump proper, since a pump normally has an inlet and an outlet, but a simple syringe body fitted with a plunger. This syringe body acts as a reservoir. In the known case, the piston is simply driven by compressed air. This very simple system, however, has major flaws, since the compression of the air depends on many parameters which are not easily controllable, such as, for example, the temperature, and the flow cannot be controlled in a really effective manner.

Other important parameters of this kind of systems are the operating cost and the difficulty of implementation. Indeed, at a time when the cost of health care is exploding in practically all countries, priority is given to simple systems, easy to implement, and overall inexpensive.

Many other devices of this type are known which each have drawbacks that the invention simultaneously overcomes.

Documents GB-A 2 153 445, EP-A 0 398 394, EP-A 0 143 895, CH-A 607 620 and EP-A 0 246 158 describe motorized infusion devices comprising a linearly driven plunger syringe body into the syringe by an electric motor. These devices however have the disadvantages of being expensive and reserved for complex applications, installed and monitored by professional personnel.

The document EP-A 0 462 508 describes a similar device in which the piston is actuated by means of the energy stored in a spring. This device has the drawback of not making it possible to obtain the linearity of the movement of the piston desired.

The present invention provides an original solution combining reliability with simplicity and precision. It relates to a device for infusion of liquid therapeutic substances according to claim 1 of the patent.

Fig. 1 schematically shows by way of example a simple device according to the invention, with constant speed of displacement of the piston.

Fig. 2 schematically shows by way of example a device according to the invention comprising simple means for programming the speed of movement of the piston.

Fig. 3 schematically shows by way of example the electronic control circuit of the device in FIG. 2.

Fig. 4 schematically shows by way of example certain features of the circuit of FIG. 3.

Fig. 5 schematically shows by way of example means for checking the proper functioning of the devices of FIGS. 1 and 2.

Fig. 6 schematically shows by way of example an electronic circuit for a device according to the invention comprising electronic programming means.

Fig. 7 schematically shows by way of example means for motorizing a device according to the invention corresponding to the circuit of FIG. 6, as well as various accessories for its implementation.

Fig. 8 schematically shows by way of example motorization means for a device according to the invention allowing the filling of the tank.

Fig. 1 schematically shows by way of example a simple version of the device according to the invention. The reservoir (1), which can consist of a standard syringe body 5cc, 10cc, etc. is formed in its useful part of a tube of constant section. This tube comprises a piston (2) comprising an internal thread (3) and driven by a lead screw (4). This lead screw (4) is held in place by an adapter (5) fixed to the tank body (1). The motorization means are contained in a housing (6) which is fixed on the adapter

(5). This box contains a power source (7), a motor-reducer (8) which can be in the form of a current clockwork movement, for example a 6% -8 movement, and a simple electronic circuit in the form an integrated circuit (9). These various elements are assembled on a printed circuit (10) which makes the necessary electrical connections. Once the motor housing

(6) assembled on the adapter (5), the hours axis of the movement (8) acting as a motor /

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reducer is coupled by the intermediate part (11) on the lead screw (4). This coupling can be one hundred percent mechanical, or magnetic. The lead screw will normally perform one revolution for each revolution of the hour axis, but it is also possible to introduce an intermediate reduction in the coupling system by means which we will not describe here.

In a classic watch movement whose motor takes one step per second, the hours axis is rotated for 43,200 steps of the motor. For a lead screw having a pitch of 1 mm, there is therefore a piston advance of 1 mm every 12 hours, or 2 mm per 24 hours. One could legitimately ask the question of knowing whether a classic watch movement is capable of developing sufficient force to ensure reliable operation of the device. Now we can calculate that an advance of 2 mm per 24 hours with a force of 1 kg *, or 10 N corresponds to a power of:

10 N * 2 10-3 m / 86 400s = 0.23 10 "" Watt

A clockwork movement motor typically consumes 1.5 10-6 Watt, or 6 to 7 times more, and we can therefore afford an overall efficiency of around 15%, which is perfectly achievable and largely sufficient to ensure the proper functioning of the device.

It is clear that a displacement of 2 turns per 24 hours may be insufficient. We can act at this time on the speed of the motor by increasing the frequency of the driving impulses. For 32 steps per second, we obtain 64 revolutions per 24 hours; for 16 steps per second, 32 turns per 24 hours are obtained; for 8 steps per second you get 16 turns per 24 hours, and for 4 steps per second you get 8 turns per 24 hours, etc.

These different piston displacement speeds correspond to different durations for emptying the tank. If, for example, once the tank previously filled by methods that we will describe later, it takes 64 turns of the lead screw to bring the piston into the final position, 32 steps per second will empty it in 1 day, 16 steps per second in 2 days, 8 steps per second in 4 days and 4 steps per second in 8 days.

In the example of fig. 1, no means are provided for choosing these different options. It is typically a very simple and therefore very inexpensive system intended for a single use, using an integrated clock-type circuit simply delivering motor pulses at the fixed frequency. It is known that such integrated circuits can be manufactured for very low prices. This execution can exist in several versions for example for a single period of use of 1, 2, 4 and 8 days, these different versions requiring as many versions of the electronic part corresponding to as many different frequencies of the motor pulses. These different versions can be obtained by as many versions of the integrated circuit (9). They can also be obtained by means of the same integrated circuit, by bonding options for example. These different options can be differentiated by an adequate marking of the case, see by different colors of it.

Note that the same motorization means can be used on several types of tanks of various capacities by playing on the pitch of the lead screws (4) and the shape of the adapters (5) as shown in the example (12).

Furthermore, the displacement of the piston is a direct relation of the number of revolutions of the motorization means, and it is therefore possible to establish a precise relation between this number of revolutions and the quantity of liquid dispensed. The only problem that could arise at this level could be a slight angular sliding of the piston. To avoid this, it would be desirable to have a not circular, but slightly oval section of the reservoir and the piston.

We said above that fig. 1 typically concerned an execution for a single use. The detail (13) shows a contact system (14) which closes when the housing (6) containing the motorization means is placed on the adapter (5). Furthermore, this adapter (5) has claws (15) which prevent the housing (6) from being removed when the latter has been put in place, in order to avoid a second use of the motorization means. There are obviously many other ways of obtaining such functions, and we will not describe them in more detail here.

Fig. 1 somehow represents a minimalist version for one use. In many cases, this version is insufficient and it is necessary to add additional functions, which automatically leads to an increase in price, particularly in terms of motorization. It is possible to overcome this drawback by dividing the infusion device according to the invention into two separate parts. The first part comprises the reservoir with its piston and its drive means. This is a simple sub-assembly, made mainly of synthetic materials, therefore inexpensive and intended for a single use. The second part includes the motorization means with its electronic control circuit and its battery. This is a more complex subset but can be reused a number of times without problems. This second part could therefore be intended for a single patient so as to avoid sterilization, but could be reused a limited number of times, for example 10.

Fig. 2 schematically shows by way of example a more sophisticated version of the device according to the invention meeting this criterion.

In this figure we find the tank (1) with its piston (2) and the adapter (5). The lead screw system is formed by three telescopic elements (20, 21, 22), the element (22) being fixed on the piston (2) and being able to form only one piece with it. Finally the axis (20) comprises a toothed wheel (23) for driving the whole. This combination of telescopic elements prevents the lead screw system from being in contact with the liquid contained in the tank and improves the seal.

We see that all these components form a

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first subset that can be treated as such. It is formed only of simple parts that can be made of synthetic material for very low prices. This first subset can therefore be discarded after use.

The second sub-assembly comprises the motorization means with its housing (6), the power source (7), the motor-reducer (8) and the integrated circuit (9) with the printed circuit (10). The coupling part (11) is formed of a toothed wheel forming a gear with the toothed wheel (23) of the first sub-assembly when the whole is assembled. This second sub-assembly is not in direct contact with the therapeutic liquid or other properly medical elements, and is not subject to any particular constraint. It can therefore without others be used several times for the same patient, this number of uses essentially depending on the life of the battery. This makes it possible to distribute the cost of the motorization means over several uses and to introduce more complex functions which will be described below.

Thus, a simple switching device can be introduced, making it possible to select, for example, the four motor speeds corresponding to the durations of use of 1 day, 2 days, 4 days and 8 days, which required in the case of FIG. 1 four different executions. This switching device comprises a screwed button (24) which maintains a selection disc (25) comprising 4 inscriptions (26) corresponding to the 4 durations which can be selected. By unscrewing the button (24), the selection disc (25) is released which can be rotated by quarter turns. When the inscription corresponding to the desired duration appears, the button (24) is screwed back on, which blocks the disc (25) in the chosen position. We will see in the following figures the electrical configuration of this selector.

Another important aspect for the use of the device according to the invention is to be able to easily check whether the device is working. For this purpose, the motor-reducer (8) has been offset relative to the axis of the lead screw system, the coupling being made by the toothed wheels (11 and 23). This allows the seconds axis to be cleared and a display (27) to be fixed on it which rotates when the device is in operation. This viewer, typically made of synthetic material so as to be very light, includes simple graphic elements allowing the user to realize very quickly whether the viewer is running or not. We will see below several variants in the use of this viewer (27).

Fig. 3 schematically shows by way of example the electronic control circuit of the device in FIG. 2.

This electronic circuit firstly comprises an oscillator (30) which can be, for example a quartz oscillator using a 32768 Hz quartz commonly used in watchmaking. This oscillator is connected to a frequency divider (31) which delivers signals of known frequencies to ensure the timing of the various functions, in our example 64, 32, 16, 8 and 4 Hz. These signals go to the inputs of a circuit selection (32) having on its output (33) signals whose frequency depends on the state of a contact selection device (34) connected to inputs of the selection circuit (32). The output (33) is connected on the one hand to a circuit for shaping the motor impulses of the motor (36), and on the other hand to the input of an engine revolution counter (37) by the via an electronic switch (38). In the particular case, the motor (36) is a clock type motor comprising a rotor formed by a cylindrical magnet magnetized perpendicular to the axis of rotation. The revolution counter (37) is connected on the one hand to a counter for the number of uses (39) and on the other hand to a commissioning circuit (40) connected to a starting contact (41) . The commissioning circuit (40) is also connected to the reset input of the divider circuit (31) and to the usage counter.

(39), as well as the switching means (38).

The operation of the circuit of fig. 3 can be explained as follows:

When the device according to FIG. 2 is put into service by assembling the tank and motorization subassemblies, after selecting the desired speed by means of the selector formed by the four contacts (34), the start contact (41) closes.

When the device has never been used and the usage counter (39) is at 0, the divider (31) is kept at 0 by the start-up circuit (40) when the contact (41) is open . There are no signals on the output (33) and the motor

(36) is stationary. By closing the start contact (41) the start circuit (40) switches and on the one hand activates the divider (31), and on the other hand switches the switching means (38) in the position shown in the figure. Simultaneously the revolution counter (37) is set to 0 by the link (42). Signals at the selected frequency appear on the output (33). These signals are put in the form of driving pulses by the circuit (35) and set in motion the motor (36). The signals of the output (33) are also connected to the input of the revolution counter (37). The latter is therefore incremented by 1 step each time the motor receives a driving pulse. Provided that the piston has been placed at the start in a determined position which we will call position 0, the state of the revolution counter

(37) is representative of the number of turns performed by the lead screw system. In a classic watch movement with a motor at 1 step per second, the hour axis makes one revolution for 43,200 steps of the motor. If the total stroke of the piston corresponds for example to 70 turns, it will reach the final position after approximately 3,000,000 engine steps.

When this condition is fulfilled, number of driving pulses = 3,000,000, a signal appears at the output (43) of the counter (37). This output is connected to an input of the start-up circuit

(40).

There are then two possibilities.

If the commissioning was short, only for a function check for example, and

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is interrupted by the opening of the contact (41), the usage counter has not been incremented and has remained at 0. In this case, the commissioning circuit (40) returns to the initial state at l opening of the contact (41) and the divider (31) is set to 0, which puts all the downstream electronic circuits out of service. It is thus possible to carry out functional checks of the device, then to store it with a minimum of consumption.

In the second case, the duration of commissioning was sufficient for a signal delivered on its output (44) by the counter (37) to increment the counter for the number of uses (39). When this condition number of uses greater than 0 is met, the counter (39) delivers on its output (45) a signal which, applied to an input of the commissioning circuit (40), will modify the behavior of that -this. When the counter (37) delivers an end-of-use signal on its output (43), or if the contact (41) is opened, the commissioning circuit (40) switches the switching means (38 ), but the divider (31) remains in service. A 2 Hz signal delivered by the modulation circuit (46) then appears on the input of the number of revolutions counter (37), the motor for its part no longer receiving any pulses is put out of service. A new start-up can only be carried out by opening the contact (41) beforehand if this has not already been done, then closing it.

This particular configuration makes it possible to limit the life of the device when it has been used for the first time, this to avoid long-term storage between the different uses. In fact, when the state of the number of uses counter is greater than 0, the number of turns (37) and number of uses (39) counters continue to run at reduced speed during the non-operation phases. of the motor, which will limit the life of the device. Indeed, the usage counter (39) has an output (47) which delivers a signal to the commissioning circuit (40) when the number of uses exceeds a fixed number, for example 10. This signal number of uses greater than 10 permanently disables the device.

The operation of the device can be summarized as follows:

at. Short-term operations make it possible to control the operation of the device. These short-term operations are not considered to be actual uses.

b. Normal use is considered as such as soon as the revolution counter has incremented a minimum number of revolutions corresponding for example to 10 000 engine steps. The number of uses counter is then incremented by 1 step. Thus any use of more than 10,000 steps of the engine is counted as a full use even if it is interrupted before term by the opening of the commissioning contact. Normally, however, this contact remains closed and use stops automatically after 3,000,000 motor steps corresponding to 70

lead screw system turns. The piston arrived at this point at the end of its travel.

vs. At each normal use, the number of use counter is incremented. When the number of uses reaches a fixed number, the device is permanently put out of service.

d. Normally the device should be used continuously, for a single patient, and discarded when the treatment comes to an end even if there are some uses available. To avoid occasional use, the meters remain in service at reduced speed after the first use. In this way the device is put out of service anyway after a certain time, even if it has only been used once.

These various limitations on the duration of a use and the number of uses are made necessary by the fact that the battery has a limited lifespan and that operation must be ensured under all conditions.

If we base ourselves again on a timepiece movement, we know that the battery is capable of ensuring a lifespan of the order of 1000 days for an engine making one step per second. This represents approximately 90 million engine steps. In our case each use represents 3 million steps which represents 30 million steps for 10 uses. There is therefore a security of 3 between the number of possible steps and the maximum number of steps authorized by the electronic circuit. Furthermore, when the device has been used for the first time, the revolution counter is incremented at 2 Hz, which represents the equivalent of 160,000 steps per day. The life of the device is therefore limited to 30 / 0.16 = 187 days even if it is no longer used in the meantime.

It remains to give more information on the modulation circuit (46) which makes it possible to modulate the signals transmitted to the driving pulse generator (35) by the circuit (32) in response to the state of monitoring circuits (48 and 49).

We saw in the previous figure that the seconds axis of the movement was equipped with a viewer making it easy to see whether the engine was running or not. By improving the system, it is possible to send coded messages, the code being represented by a very particular alternation of operations and stops of the viewer. For example, the circuit (48) is an end-of-life detector, and the circuit (49) is a missed step detector. These two types of circuits are well known in integrated circuits for watchmaking and will therefore not be described here. When the circuit (48) detects the end of battery life condition, it transmits a signal to the circuit (46) which delivers a first modulation signal to the circuit (32) which will deliver on its output (33) corresponding coded signals at the end of battery life. Likewise when the circuit (49) detects the condition of missed steps, it transmits a signal to the circuit (46) which delivers a second modulation signal to the circuit (32) which will deliver on its output (33) coded signals corresponding to detection of missed steps. And so on for other parameters.

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This is a kind of alarm system which allows the user to be informed of certain peculiarities of the operation of the device. Unlike the conventional buzzer alarm system which can be installed without problems in the device according to the invention as in watches and other autonomous devices, but which can only be actuated for very short moments so as not to drain the battery, this alarm by interposed rotary display consumes no additional energy. In addition, this viewer can operate continuously, while short acoustic signals can easily go unnoticed if the person is distracted, for example watching television. We will see below some forms of modulated signals used by the rotary viewer.

Finally, in the cases described so far, there is always an infusion of a fixed quantity, ie the contents of the reservoir, and programming of the time necessary to empty this reservoir, ie 1, 2, 4, or 8 days. A slight modification allows you to work at a fixed infusion time, for example 1 day, and to vary the quantity infused, ie 1, 1/2, 1/4 or 1/8 of the reservoir. For this, the input of the counter (37) is connected directly by the switch (38) to the 32 Hz output of the divider (31) by the link (50). Thus the lap counter (37) becomes a simple duration counter of 3 million / 32 = 90,000 seconds or approximately 1 day. The number of revolutions of the motor during this period will therefore vary depending on whether it is supplied at 4, 8, 16 or 32 steps per second. These variants can be distinguished from each other, as in fig. 1, by color variants of the plastic boxes.

Fig. 4 schematically shows by way of example certain features of the circuit of FIG. 3.

Under 4a is shown in a very simplified manner the selection means 34 of FIG. 3. These selection means comprise the selection disc (25) of FIG. 2. This disc has four protuberances (60) carrying on their respective faces the inscriptions 1, 2, 4 and 8. This disc can be positioned by quarter turns in four different positions. The disc (25) comprises a triangular spring (61), the three ends of which come opposite contact zones of the printed circuit. It can be seen that, in the four positions, one of the ends is in contact with VDD, another with the STOP, while the third touches successively S1, S2, S3 and S4. When the button (24) of fig. 2 is unscrewed, the spring (61) is no longer in contact with the printed circuit and all the contact areas are in the air. When the disc is placed in the desired position and the button (24) is screwed back in, the spring (61) establishes contact between the three contact zones corresponding to the chosen position.

Under 4b are shown the form of the modulated signals for transmitting visual messages via the rotary viewer. This modulation alternates periods with signals of frequency 2f, signals of frequency 0 and signals of nominal frequency f, so that the average frequency of the signals remains f. Thus the transmission of these modulated signals can be maintained ad eternum, without influencing the average speed of displacement of the piston. Short-term variations over a few seconds have no influence on the liquid flow rate due to the very large reduction between the seconds axis and the lead screw. Fig. 4b shows by way of example 4 different modulations corresponding to the detection of the end of battery life (62), to the detection of missed steps (63), to the penultimate possible use (64) and to the last use possible.

Fig. 5 schematically shows by way of example means for checking the proper functioning of the devices of FIGS. 1 and 2. Indeed the rotary viewer of fig. 2 is a good indicator of short-term functioning, but it would also be useful to have a long-term monitoring system. We know that sick people are easily anxious and the existence of such a means of control can be reassuring.

We know that the piston (70) moves at constant speed from a starting point (71) to a maximum point (72). The piston is brought into the starting position for filling by the nursing staff, and it is easy for the latter to check that this starting position is correct when the device is put into service. As the piston moves by a precise quantity at each hour, one can associate the position of this one with the hour of the day by means of an adhesive strip (73) carrying a double graduation in relation to the selected duration, either a 24-hour double graduation for the duration of 1 day, a 48-hour double graduation for the duration of 2 days, etc. The nursing staff cut the adhesive tape a little before the start-up time in the first scale and a little after this time in the second scale. This strip is then glued to the tank in such a way that the start-up time corresponds to the starting position of the piston.

Thereafter, the patient can read the position of the piston on the scale at any time, a position which must correspond to the time of day. In our figure the piston was put into service at 9:30 am and it must be around 11:00 pm. If this is not the case, particularly if the piston is late, it means that there has been a blockage. , and you must notify the nursing staff immediately. This is a rudimentary system but one that can be of great service.

The preceding figures show simple systems without programming or with very rudimentary programming means which can be put into service by any nursing staff with minimum training. This is important insofar as overly complicated systems can provoke understandable rejection reactions given the work overload and the multiplicity of medical novelties appearing on the market. However, in certain cases, it is important to have more extensive possibilities, for example involving more sophisticated programming means.

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Fig. 6 schematically shows by way of example an electronic circuit for a device according to the invention comprising electronic programming means.

The devices shown in the previous figures use electronic circuits using logic of the conventional type. However, it is well known that at present there are microprocessors of the “one chip” type with low consumption making it possible to obtain equivalent functions by programmed logic. These microprocessors include among other memory circuits of the RAM type and timer circuits making it possible, in this case, to program the speed of the motor as a function of time. These circuits also include a certain number of inputs and outputs making it possible either to transmit information from the inside to the outside in logical form, or to receive information from the outside either in logical form or in analog form, some of these microprocessors comprising analog type amplifiers making it possible, for example, to directly manage external sensors, such as temperature, pressure sensors, etc. In addition, most microprocessors of this type also include outputs for LCD type display making it possible to manage relatively complex displays.

Fig. 6 shows an electronic circuit of this type comprising in the area (80) the functions shown in FIG. 3. However, the selection of the motor speed is given by a RAM type memory (81) addressed by means of a timer circuit (82). Each time period defined by this timer circuit (82) corresponds to a motor speed programmed in the corresponding section of the RAM memory. Thus, if the timer circuit (82) defines 24 periods of time corresponding to the 24 hours of the day, to which correspond 24 speeds programmed in 24 positions of the RAM memory (81), om can thus program hour by hour the flow rate of the device of infusion according to the invention, this as needed. This is an important improvement since it is possible to really adapt the treatment to the smallest details to the patient's own needs.

The RAM circuit (81) and the timer circuit (82) are connected by a central computing unit (83) which manages all of the functions of the electronic circuit. Thus, this central computing unit can manage an LCD type display (84) and display a certain number of parameters of which we will give some examples later. Furthermore, this central unit can manage auxiliary circuits such as the end-of-life detection circuits (85) and the missed step detector circuit (86). It is obvious that, in the case of FIG. 6, it is no longer necessary to use a rotary viewer to transmit messages to the user, but that the LCD display can be used directly for this purpose, either by "flashing" the display, or using special symbols or display combinations reserved for each situation, for example "bt" for insufficient battery, "pr" for missed steps, etc.

Another interesting parameter which can be managed by the central computing unit (83) and displayed by the LCD display (84) is the position of the piston. As the speed varies over time, it is no longer possible to associate the position of the piston with the time of day as before. On the other hand, by connecting the central computing unit (83) to the revolution counter by the link (87), it is possible to calculate and display the position of the piston. For example, if the piston makes all of its movement in 70 turns of the lead screw system, it will make 1 tenth of this movement every 7 turns. Using a graduation similar to that in fig. 5, but graduated from 0 to 10 for example, and by displaying on the LCD display the number of times 7 laps that the lap counter has counted, a direct relationship is obtained between the value displayed on the LCD (84) and the position of the piston on the scale. This makes it possible to check at all times if the operation of the device is correct and if there has been no blockage of the piston.

The central computing unit in fact makes it possible to communicate with other internal elements of the electronic circuit such as the display (84) and the detectors (85 and 86), but also with elements external to this one, and first of all place with external RAM programming means (81) which will be described in fig. 7.

In addition to the RAM programming means, it is possible to add other external functions. Let us take the example of messages which must draw the patient's attention to certain malfunctions of the device according to the invention. It has been described how these messages can be displayed by a rotary display or by an LCD display. It has also been said that an acoustic system such as those used for example in watches could be incorporated into the electronic circuit according to the invention, which does not in itself represent a technical innovation. All these systems are interesting but do not constitute a real alarm system and the messages in question can escape the patient if he is distracted, sleeps, watches TV, etc. However in certain critical cases, it is important that the nursing staff or the patient is really put on alarm. To this end, the central computing unit comprises means of communication with the outside (88) which can be connected to an outside alarm unit.

(89) with its own power source

(90) and a circuit (91) for receiving and processing the information transmitted by the communication means (88), a circuit arranged so as to activate an audible alarm (92) having the required power.

It should also be noted that the communication means (88) make it possible to introduce into the central computing unit (83) other information coming from the outside, particularly coming from an external sensor.

Fig. 7 schematically shows by way of example means for motorizing a device according to the invention corresponding to the circuit of FIG. 6, as well as various accessories for its implementation.

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In fig. 7, we recognize the motorization means fixed on the adapter (100) of the tank partially shown. These motorization means include the motor (101) driving the axis (102), a power source (103), the microprocessor circuit (104) and the LCD display (105). These elements are assembled for example on a printed circuit mounted in the housing (106) according to techniques well known to those skilled in the art. The electronic circuit is connected to the outside by a connector (107) provided with a cable (108). One can obviously use other known connecting means by magnetic, optical or acoustic coupling.

A first use of these connection means to the outside is to connect the electronic circuit to a sensor acting at least indirectly on the RAM circuit (81) so as to adapt the speed of the motorization means as a function of a determined parameter. Thus in the treatment of diabetes for example, one could adapt the flow of insulin as a function of the sugar level in the blood, rate measured permanently by a suitable sensor.

A second use of these connection means is to connect the electronic circuit to external programming means. There are very many programming systems and procedures known to those skilled in the art and we will not describe in detail the configuration of these means. However, these are preferably physically in the form of a portable instrument.

(110), light and handy, with a keyboard

(111) for data entry, and display

(112) for reading information transmitted by the instrument. To facilitate the work of nursing staff, this instrument includes a system for reading a removable memory (113). This removable memory (113) is dedicated, at least for the duration of the treatment, to a particular patient and contains information on the treatment thereof. Thus, when the nursing staff has to program a device according to the invention for a specific patient, he first sets up the removable memory (113) dedicated to this patient, and can then introduce the necessary information into the patient by simple manipulations. RAM circuit (81) of the motorization means of FIG. 6.

an important point should be noted at this level, in the sense that the means of communication between the electronic circuit of the device according to the invention and the programming means can be bidirectional, and that there can be interaction between the information contained in the RAM (81) and the programming means themselves. For example, it is possible for the programming system to read the still available capacity of the tank as a function of the number of revolutions made, and to trigger an alarm in the event that the requested program requests a higher capacity. Likewise, the electronic circuit of the device according to the invention can give the programming system information on the operations already carried out, for example the quantities and durations programmed since the start of the treatment, dates of commissioning, etc.

A third use of these connection means is to connect the electronic circuit to a monitoring and alarm system (115) as described in fig. 6. This system can be autonomous and of small dimensions so that it can be carried by the patient, on the belt for example. This system can also be linked to a central monitoring station so that third parties can be notified if necessary. The fact that this monitoring and alarm system is separate from the motorization means themselves makes it possible to maintain a low operating cost, since the monitoring system is a 100% reusable accessory, and is only put into service when 'if necessary. Therefore additional functions can be introduced, for example the display of messages by means of an LCD display (116). This display being more important than that of the motorization means (105) it is possible to read more complete information, information which is transmitted by the microprocessor circuit (104) to the monitoring system (115) via the connection means. (107, 108). Thus, during home treatments, it will be possible for the patient to communicate to the nursing staff, by telephone for example, precise information on the operation of the device, information displayed on the display (116).

It can be seen that the perfusion device according to the invention is integrated into a very complete treatment system ranging from the simplest to the most sophisticated applications, while keeping the same basic principle. The system can be supplemented in many ways, for example by adding additional security elements either at the level of the operation of the device, or to prevent misuse of the device. However, these additional elements do not modify the basic principle of the device according to the invention, and their description in detail would add nothing to the understanding of the device.

Now that we have described several ways to empty the tank, it remains to describe a simple method to fill it. This problem is important insofar as this operation must be easily accessible to the nursing staff.

Fig. 8 schematically shows by way of example motorization means for a device according to the invention allowing the filling of the tank.

To fill the tank, first place the piston in its lowest position, then reverse the direction of rotation to draw the liquid into the tank. To carry out this operation quickly and in good conditions, one can use an accessory as shown in fig. 8. This accessory comprises a reduction motor (120) with two directions of travel, for example a DC motor on which the polarity of the supply voltage can be reversed. This reduction motor is much more powerful than the reduction motors described above, so that the lead screw system can be driven at a sufficient speed for the operation of rem5

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pleating does not take too long, 2 turns per second for example. In the example described, the motor (120) is powered by a commercial battery (121) through a switching device (122) driven by a three-position slide (123). This slide switch allows in a first position to rotate the motor clockwise, in the intermediate position to stop the motor, and in the third position to rotate the motor in the opposite direction, at the way of spit motors. The motor (120) comprises a coupling part (124) which drives the axis of the mother screw system. The whole is mounted in a housing (125) on which the reservoir is fitted with its adapter.

The filling operation takes place as follows:

at. The tank is emptied to the maximum of the air it contains by pushing the piston into its lowest position.

b. The liquid is aspirated by reversing the direction of travel.

vs. Once the tank is partially filled, place everything with the mouth up, so as to raise the residual air towards the outlet.

d. The direction of travel is again reversed to empty this residual air.

e. When the reservoir contains only liquid, it is inverted again and the liquid is sucked until the piston is in position 0.

This operation is simple to do, and it is easy for the nursing staff to check visually if the reservoir still contains air bubbles, in which case we can start again at point c. Thereafter, taking into account the tightness of the piston and the fact that the normal means of motorization are unidirectional, it cannot form air bubbles inside the tank. Therefore it is not necessary to provide security at this level in the device according to the invention, unlike what happens with pumps of the peristatic type.

The accessory shown in fig. 8 is a simple and easy-to-use accessory available to nursing staff at all levels, it is very clear that, for industrial productions, we can use much more sophisticated means, notably making it possible to fully automate the process filling.

Furthermore, in more rudimentary versions, this motorized system can be replaced by simple mechanical means, such as a crank system for example.

There are many other possible combinations of the infusion device according to the invention, but their description would not provide any additional element for the understanding of its operation. So we will not list them here.

Claims (1)

Claims 1. Portable device for perfusion of liquid therapeutic substances comprising firstly a reservoir having a constant section in its useful part, this reservoir comprising a piston and mechanical means for linear drive of this piston, secondly motorization means of the rotary type with control means for these motorization means, and thirdly coupling means between said mechanical linear drive means and said rotary type motorization means arranged so that the displacement of said piston is a direct relation to the number of turns performed by said means motorization means, device characterized in that said motorization means consist of an electric motor and mechanical elements for transmitting and reducing movement of the type of a watch movement and in that said electric motor is powered by a source autonomous power supply. 2. An infusion device according to claim 1, characterized in that said autonomous power source is a button type battery. 3. A device for infusion of therapeutic substances according to claim 1, characterized by a switching member arranged so as to directly or indirectly put into operation the motor control means during the assembly of two sub-assemblies constituting, after assembly, the device. 4. Device for infusion of therapeutic substances according to claim 3, characterized in that it comprises security elements arranged so as to prevent disassembly of the device when the two sub-assemblies have been assembled. 5. Device for infusion of therapeutic substances according to one of claims 1 to 4, characterized in that said control means comprise an electronic circuit including at least a time base in the form of an oscillator and means for dividing the frequency of this oscillator arranged so as to define sequences of operations. 6. Device for infusion of therapeutic substances according to claim 5, characterized in that said electronic circuit comprises at least means for interrupting the supply of motor impulses when the number of motor impulses counted by counting means reached a predetermined value corresponding to the maximum displacement of the piston. 7. Device for perfusion of therapeutic substances according to claim 6, characterized in that it comprises means for counting the number of uses arranged so as to count the number of uses each time the counter of motor impulses reaches said predetermined value. 8. Device for perfusion of therapeutic substances according to claim 7, characterized in that the means for counting the number of uses are connected to a circuit arranged so as to put the device out of service when the number of uses reaches a number predetermined. 5 10 15 20 25 30 35 40 45 50 55 60 65 10 17 CH 685 461G A3 18 9. Device for perfusion of therapeutic substances according to claim 5, characterized in that said electronic circuit comprises electromechanical switching means connected to a selection circuit arranged so as to choose the frequency of the motor pulses as a function of the position of said means of commutation. 10. Device for infusion of therapeutic substances according to claim 7, characterized in that said electronic circuit comprises means arranged to put the device out of service after a determined period, these means being engaged when the pulse counter and d 'uses is incremented by at least one unit. 11. A device for infusion of therapeutic substances according to claim 1, characterized in that the motor drives a rotary viewer mounted on an axis of a gear train forming part of said mechanical elements for reducing movement. 12. Device for perfusion of therapeutic substances according to claims 5 and 11, characterized in that said electronic circuit comprises a circuit for modulating the frequency of the motor pulses arranged so as to generate coded messages according to the state of circuits internal, in particular end-of-life detection circuits, detection of missed steps and / or counting of the number of uses, said coded messages being able to be read on said rotary viewer. 13. Device for perfusion of therapeutic substances according to claim 12, characterized in that the average frequency of the driving pulses of the messages coded by said modulation circuit remains constant and equal to the nominal frequency chosen. 14. A device for infusion of therapeutic substances according to claim 1, characterized in that the reservoir has an area on which a control scale can be fixed, a scale arranged so as to establish a relationship between the position of the piston and the time of the day. 15. A device for infusion of therapeutic substances according to claim 14, characterized in that the said graduation is placed on an adhesive tape. 16. Device for perfusion of therapeutic substances according to claim 5, characterized in that said electronic circuit comprises means for managing an LCD display and displaying on said LCD display the position occupied by the piston on a scale provided for this purpose. 17. A device for infusion of therapeutic substances according to claim 5, characterized in that said electronic circuit comprises means arranged to manage procedures for communication with the outside, possibly bidirectional. 18. Device for perfusion of therapeutic substances according to claims 1 and 12, characterized in that said electronic circuit comprises a missed step detection circuit arranged so as to analyze the voltage and / or current induced in the motor and to deliver a signal when it does not comply. 19. A device for infusion of therapeutic substances according to claims 1 and 12, characterized in that said electronic circuit includes time counting means arranged so as to put the device out of service after a determined period, these counting means being engaged. when the usage counter is incremented by at least one unit. 20. A device for infusion of therapeutic substances according to claims 1 and 12, characterized in that said electronic circuit comprises at least random access memory (RAM) circuits. 21. A device for infusion of therapeutic substances according to claims 1 and 12, characterized in that said electronic circuit comprises an LCD display and means for managing this display. 22. Device for perfusion of therapeutic substances according to claims 1, 12 and 20, characterized in that said electronic circuit is formed at least partially of circuits in programmed logic comprising read only memory circuits (ROM). 23. A device for infusion of therapeutic substances according to claims 1, 12 and 20, characterized in that said random access memory circuits are programmed so as to fix the frequency of the motor pulses and thereby the speed of movement of the piston as a function of the time. 24. device for infusion of therapeutic substances according to claims 1, 12, 20 and 21, characterized in that said electronic circuit comprises means connected to the revolution counter and to the means for managing the LCD display, arranged so as to calculate and display on said LCD display the position occupied by the piston on a scale provided for this purpose. 25. device for perfusion of therapeutic substances according to claims 1, 12, 20 and 21, characterized in that said electronic circuit comprises means connected to means for managing the LCD display and to certain internal circuits, in particular the step detector failures, and / or the usage counter, means arranged so as to display on said LCD display messages relating to the state of these circuits. 26. Device for infusion of therapeutic substances according to claims 1 and 12, characterized in that said electronic circuit comprises means arranged to manage procedures for communication with the outside, these means comprising at least connection means connectors , magnetic optical or acoustic towards the outside. 27. A device for infusion of therapeutic substances according to claims 1, 12 and 26, characterized in that said means for managing procedures for communication with the outside are of bidirectional type. 28. Device for perfusion of therapeutic substances according to claims 1, 12 and 26, characterized in that said means of communication 5 10 15 20 25 30 35 40 45 50 55 60 65 11 19 CH 685 461G A3 nication and connection are arranged so as to allow the connection of said electronic circuit with an external sensor. 29. An assembly comprising a device for infusion of therapeutic substances according to claim 17, and a sensor, characterized in that said communication and connection means are arranged so as to allow the connection of said electronic circuit with said sensor, to control the device flow at a parameter entered by the sensor. 30. An assembly comprising a device for infusion of therapeutic substances according to claim 17, and an apparatus for programming at least part of the content of the random access memory (RAM) circuits, characterized in that said means of communication and of connection are arranged to allow the connection of said electronic circuit with said programming device. 31. An assembly according to claim 30, characterized in that said external programming device comprises a removable memory containing information corresponding to the processing to be programmed. 32. Assembly comprising a device for perfusion of therapeutic substances according to claim 17 and a monitoring and / or alarm system, characterized in that said communication means are arranged so as to allow the connection of said electronic circuit with said system monitoring and / or alarm. 33. An assembly comprising a device for perfusion of therapeutic substances according to claims 20 and 25 or 26 and an apparatus for external programming of at least part of the content of the random access memory (RAM) circuits, characterized in that said means of communication and link are arranged to allow the connection of said electronic circuit with said device. 34. An assembly according to claim 33, comprising a device for infusion of therapeutic substances according to claim 25 or 28, characterized in that said external programming device comprises a removable memory containing information corresponding to the treatment to be programmed. 5. An assembly comprising a device for infusion of therapeutic substances according to claims 1, 12 and 26 and an external monitoring and / or alarm system, characterized in that said communication and connection means are arranged so as to allow the connection of said electronic circuit with said external monitoring and / or alarm system. 36. An assembly according to claim 35, characterized in that said external monitoring and / or alarm system is arranged so as to be autonomous and portable. 37. An assembly according to claim 35, characterized in that said communication and connection means are arranged so as to allow the connection of said electronic circuit with an external sensor. 5 10 15 20 25 30 35 40 45 50 55 60 65 12