FR2490958A1 - METHOD AND APPARATUS FOR INTERMITTENTLY DISTRIBUTING MEDICAL SOLUTION IN MINIMAL DOSES - Google Patents

Abstract

METHOD AND APPARATUS FOR INTERMITTENTLY DISTRIBUTING A MEDICAL SOLUTION IN MINIMAL DOSES. THE APPARATUS ACCORDING TO THE PRESENT INVENTION INCLUDES A CONTROL MEANS 11 WHICH IS CONNECTED TO A MOTOR 6 DRIVING A PERISTALTIC PUMP 8. THE CONTROL MEANS 11 INTERMITTENTLY ACTIVATES THE MOTOR FOR A TIME CORRESPONDING TO AN ENTIRE MULTIPLE OF THE PULSED PERIOD OF THE PERISTALTIC PUMP. A CUMULATIVE DOSE PER UNIT OF TIME CAN BE MODIFIED BY A MEANS 12 SERVING TO SELECTIVELY ESTABLISH THE ENTIRE MULTIPLE OF THE PULSATION PERIOD OF THE PERISTALTIC PUMP AND OR A MEANS 13 TO SELECTIVELY ESTABLISH THE INTERVAL OF ACTION TIME OF THE MOTOR.

Description

Method and apparatus for intermittently dispensing

  a medical solution in minimal doses.

  The present invention relates to a method and apparatus for intermittently dispensing a medical solution in minute doses over a long period of time by means of

a peristaltic pump.

  Devices for administering medical solutions,

  such as hormonal agents and chemotherapeutic agents

  minimal doses for a long period of time

  lO well known. Such devices are now of the type

  tif and use a battery as a way energy source

  that the treatment can be prolonged effectively without

  ruin the patient's daily life. In general, these devices distribute medical solutions intermittently and not continuously, mainly because they

  in the case of prolonged use, it is necessary to

  to minimize the current consumption of the batteries and to obtain operation of the drive section in

  optimal conditions. Another reason is that an inJec-

  continued use would result in an overload of medical

  wedge that would harm the patient. In addition, an extremely complicated mechanism is required to continuously inject medical solutions at minimal doses. For example, in the case of insulin administration, a daily dose of 10 ml of insulin solution is administered little by little at 15 minute intervals. It is virtually impossible to inject this minute volume continuously. Most injection devices use a peristaltic pump

  intermittently operated so as to distribute

  to drink a medical solution by dosesminim essur a long

periode of time.

  Peristaltic pumps propel fluid through a tube locally applying a pressure to the tube so as to pinch the tube and gradually move the point

  pinching towards the discharge end. The clamp

  The tube stops when the pinch point reaches the discharge end. This operation is repeated cyclically. Unfortunately, because the pinched tube returns to its cylindrical shape immediately after nip stops, the liquid supply is momentarily interrupted at this point. A countercurrent appears at the discharge end. In other words, a pulsation occurs in the liquid supply. Various processes have been proposed

  Until now to prevent this pulsation. All procedures

  previous years have sought to reduce the influence of

  pulsation by bringing the flow of

liquid to be dispensed.

  Because a pulsation appears in an inherent way in peristaltic pumps, the apparatus for dispensing

  medical solutions in minimal doses over a long period of time

  time period using such peristaltic pumps has the disadvantage that a noticeable error occurs in the

  dose for each individual distribution if the pulse cycle

  is selected incorrectly. Such an error in the dose has an undesirable influence on the patient. This error is not important in relation to the envisaged dose if the simple or individual distribution time is sufficiently longer than the pulsation period. However, an error in the distribution dose will deviate significantly from

  the precision sought if the time of an indi-

  The vidual is more cclurt or a little longer than the pulse period. If the operation of the pump is continuous, an error in the delivery dose due to the pulsation is quickly compensated. On the other hand, because a long time interval separates a distribution of the following distribution in the case of intermittent operation, an error in the dispensing dose is not compensated for until the distribution follows. start. In intermittent operation, one can not avoid a variation in a

  dose of individual distribution as a result of the pulsation.

  The inventors have researched the peristaltic dispensing apparatus to find how to control the apparatus [1 to eliminate the influence of the

  inherent pulsation on each dose of distribution.

  The pulsation appears when the pinching of the tube stops immediately after which pinch point has reached the discharge end. The amount of the solution discharged by the displacement of the pinch point from the suction end to the discharge end is always constant. Since the displacement of the pinch point from the suction end to the discharge end is accurately repeated, the amount of the solution propelled between the beginning of the pinch point displacement from a certain position and the end of the displacement at the initial position is always constant. In others

  In other words, the quantity of the solution discharged during a

pulse period is constant.

  If the single or individual intermittent dose was set to an integer multiple of one pulse period, the successive doses could be equal

  whatever the pulsation occurring in the perishable pump

  taltique. In the prior art, the dose of

  It was difficult to adjust the dose to a desired value for a particular user. Recently, we. has developed devices

  input having a digital electronic circuit / control

  than. incorporated and in which a numerical value

  dose may be introduced by the user.

  tor. In such devices, an input value can be set as an integer. With a device

  combined with a digital control device

  the distribution dose in proportion to the established value. Therefore, the user can easily

  establish, that is, set a desired value. Another advantage

  is an increased accuracy as a result of the numerical control

  than. In such a controlled dispensing apparatus, all adjustable dispensing doses are multiples of the minimum unit. The dose per intermittent individual distribution can be constant through the use of the minimum unit

  corresponding to a pulsation period.

  An object of the present invention is therefore to provide

  a process and / or apparatus for dispensing a medical solution.

  dose per minute over a long period of time using

  a peristaltic distribution system, in which

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  the intermittent and intermittent dose is always

  Days maintained at a precise constant value.

  Another object of the present invention is to provide

  a method and apparatus of the type mentioned above, in which the dose by intermittentindividual distribution

  can be electrically modified.

  According to the first aspect of the present invention, the Applicant has created a method for intermittently dispensing a medical solution in minimal doses over a

  long period of time by means of a distribution device

  characterized in that the dose by individual intermittent dispensing is set to be equal to a dose corresponding to a period which is an integer multiple of the pulsation period of the device

  peristaltic distribution, thanks to which the dose

  vidual is constant regardless of the pulsation. Preferably, a cumulative dose per unit time may be varied depending on the therapy applied to the patient and the symptom presented by the patient. The cumulative dose may be varied by varying the integral multiple of the pulse period and / or the interval of the intermittent distribution. According to the second aspect of the present invention, the Applicant has created an apparatus for intermittently dispensing a medical solution in minute doses over a long period of time through the intermittent operation of a peristaltic pump, characterized in that it comprises a motor for driving the peristaltic pump and a control means for intermittently actuating the motor for a time corresponding to an integer multiple of the pulsation period of the peristaltic pump. The apparatus further comprises means for selectively setting the integral multiple of the pulsation period of the peristaltic pump and / or means for selectively adjusting the time interval of the actuation of the motor, by to what a cumulative dose per unit of time is selectively modified to meet a particular therapy and symptom

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  The peristaltic pump that can be used in the present invention can be of the type with rollers, fingers as well as any other type. When using a roller type peristaltic pump, the rotor is fixedly attached to a rotary drive shaft and a plurality of equidistant rollers

  are rotatably mounted on the rotor in a device

  symmetrical mutual relation to the drive shaft.

  The rotary drive shaft may preferably be associated with a revolution detector which detects the rotation of the shaft so as to output detection pulses in proportion to the number of rotations detected. The preferred engine to drive the

  Peristaltic pump is a stepper motor.

  The present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a pebble type peristaltic pump; Fig. 2 is a diagram showing the waveform of the peristaltic pump; Fig. 3 is a block diagram of one embodiment of the present invention utilizing a DC motor; and Fig. 4 is a block diagram of another embodiment of the present invention using an engine

step by step.

  We will describe in more detail by referring

  illustrated embodiments using a perishable pump

  talty of the roller type the process for intermittently dispensing a medical solution in minimal doses according to

the present invention.

  With reference to FIG. 1, it will be seen that there is shown a typical peristaltic pump of the roller type comprising a rotary drive shaft 3, a rotor 1 permanently fixed to this shaft, and a plurality (four) d-years a present embodiment, pebble 2 equidistant, mounted

  rotatingly on the rotor 1 in a mutual arrangement.

  the symmetrical with respect to the shaft 3. A stator 4 comprises a semicircular cavity which is arranged concentrically to the rotor. A tube 5 having an input connected to a source

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  medical solution and an output connected to a needle (not shown) extends between the rotor 1 and the stator 4. The tube is clamped in two or three points by rollers 2 bearing against the stator cavity through the tube. As the rotor 1 rotates in the direction represented by an arrow, the medical solution is delivered in a quantity or dose defined by the quantity in the

  the tube 5 between the two adjacent points pinched by the rollers.

  A pulsating flow or peristaltic discharge occurs when the front roller 2 ceases to be in contact with the stator 4 at the discharge end. Since four rollers are mounted on the rotor 1 in the present embodiment, a pulsation takes place four times per revolution of the rotor 1. The

  symmetrical arrangement of the pebbles results in

  pulsating elements with the same waveform. The waveform

  of the pulsating flow is shown in FIG.

  When an intermittent distribution is performed in equal sections of the pulsation period represented in t and t 'according to

  the previous method, the quantity or dose of solution

  The vapor varies each time under the influence of a pulsation as can be understood from FIG. 2. According to the present invention, an intermittent distribution is performed in a dose corresponding to a pulsation period represented by T or T 'or by an integer multiple of a period. Then each

  dose is maintained continuously at a predetermined dose value.

  for a long period of time.

  A preferred embodiment of the present invention is illustrated by the block diagram of FIG. 3. The structure of the embodiment represented by this block diagram will be described together with its operation. Reference 8 designates a peristaltic pump of the roller type

  as shown in Figure 1. The drive shaft

  The rotary rotor of the pump rotor is coupled to the final output shaft of a reduction gear train 7 whose input shaft

  primary is coupled to a DC motor 6. Rotation

  tion of the motor 6 causes the entrainment of the pump 8 via the shaft. A drive shaft of the pump 8 associated with a detector 9 turns that detects the rotation of the pump shaft so as to generate the detection pulses in proportion to the number of revolutions. The detector 9

  of turns can be a pulse encoder, for example.

  Reference numeral 12 denotes a dose adjustment device where the dose is set by means of a rotary switch with a digital display, for example, a set value or set value appears at the output in the form of a digital signal BCD (binary). decimal coded). The device 12 of

  dose adjustment is electrically connected to a

  in the form of a pre-set down counter

  ble, for example. The control circuit 11 is electrically connected

  only to a timer 13 which transmits a preset signal

  to the control circuit 11 whenever an internal distribution

  termittente must be performed. At the reception of the signal

  preset of the timer 13, the control circuit 11 introduces

  The digital signal BCD of the dose setting device 12 is fed into the counter to preset the contents of this counter to the setpoint. The meter is designed so

  its "0" output provides a training signal to a cir-

  Cooks motor drive 10 so as to operate the motor when the contents of the meter has a value other than "0". Because the preset content of the comp is

  the dose setting value, the output "0" of the counter

  Nit a motor drive signal under the action of which the motor 6 controls his tour. Depending on the rotation of the motor, the 9-revolution detector generates detection pulses. A divider 14 having a 1 / n frequency division ratio is connected between the detector 9 and the control circuit 11 when the ratio between the number of pulses and the number of detection pulses is 1: n. The divider 14

  can be deleted when this ratio is 1: 1.

  The detection pulses from divider 14 or directly from detector 9 are applied to the counting input of preset counter 11. Counter 11 subtracts "1" from its contents each time it receives a detection pulse. When the contents of the counter 11 are finally reduced to "0", the output "0" stops supplying a motor drive signal, whereby the motor 6 stops. The detector 9 also has the trouble of generating

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  a detection pulse, so that the contents of the counter

  is kept at "0". As a result, the engine, and consequently

  the perimeter pump is kept at standstill

  next moment of distribution. At the next moment of distribution

  bution, the timer 13 provides at its output a signal

  preset and the operation mentioned above is then carried out

killed again.

  Thanks to the above arrangement, the counting input

  the preset counter 11 receives detection pulses

  At the point corresponding to the same positions on the pulse waveforms generated by the pump 8, therefore, the roller type peristaltic pump 8 always starts the distribution at the same positions on the pulse waveforms independently of the preset value in

  the dose adjustment device. The dose of the solution dis-

  tribe between start and stop of the pump 8 is always

  Days an integer multiple of the amount of solution dispensed during a pulse cycle. If the minimum unit of doses

  is greater than the quantity of solution distributed

  during a pulsation cycle, the divider 14 must pre-

  a division ratio of l / nm, where mn is a number

integer equal to 2 or more.

  Another embodiment of the present invention

  is represented by the block diagram of FIG.

  FIG. 4 is similar to that of FIG. 3, except that the detector 9 of the TME is removed from the arrangement of FIG. 3 by replacing the conventional DC motor 6 with a 6 'step motor. and that a drive pulse generator 15 is added. Unlike the conventional DC motor, the stepper motor requires a special drive circuit 10 'because the simple application of voltage is not enough to drive the stepper motor. Because the stepper motor turns one step each time it receives a pulse at its input, it can

  order the number of turns based on the number of

  input impulses. The drive pulse generator generates pulses at a constant frequency when the contents of the preset down counter 11 are not "0" but stops the generation of pulses when the contents of the counter are

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  "O". The divider 14 divides the number of driving pulses

  and provides the split value to the count input of the

counter 11.

  If P is the number of steps required for the stepper motor 6 'to take a turn, if Q is the ratio of

  reduction of the reducing train 7 and if R is the number of lmpul-

  As per turns of the peristaltic pump 8, the divider 14 has a division ratio of R / PQ. The minimum dose unit on the basis of which any desired dose is set by the dose adjustment device 12 then becomes equal

  the amount of solution dispensed during a pulse cycle

  which eliminates any variation or error in the dose due

  pulsation, as is the case in the first embodiment.

  tion shown in Figure 3.

  Although a pebble-type peristaltic pump was used in the embodiments described above,

  the present invention is not limited to such a pump.

  Finger type peristaltic pumps or any other type of device could equally well be used in the present invention.

  another peristaltic pump provided that it can

  a cyclic flow a pulsating flow.

  As seen from the foregoing, the dose of a single intermittent medical solution may be maintained at a desired fixed value for a long period of time by the present invention. The dose may be varied selectively in accordance with the therapy applied to a patient as well as the symptoms presented by that patient. The control system is simple and reliable. The

  The present invention has great advantages over the

than earlier.

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Claims (8)

  1. Method for intermittently dispensing medical solution in minute doses for a long time   period of time by means of a device for distributing   characterized in that the individual intermittent dispensing dose is set to be equal to a dose corresponding to a period which is an integer multiple of the pulsation period of the device   peristaltic distribution, thanks to which the individual dose   the is constant regardless of the pulsation.   A method for intermittently dispensing a medical solution in small doses according to claim 1, characterized in that a cumulative dose per unit of time can be varied by varying the integer multiple of   the pulse period and / or the time interval of dis- intermittent tribution.   Apparatus for intermittently dispensing medical solution in minute doses over a long period of time by intermittent operation of a peristaltic pump, characterized by comprising: a motor for driving said peristaltic pump; and   control means for operating intermittently   attempts said engine for a time corresponding to a multiple   whole of the pulsation period of said peristaltic pump.   4. Apparatus for intermittently dispensing a medical solution in minute doses according to claim 3, characterized in that it comprises means for selectively adjusting the integral multiple of the pulsation period.   of said peristaltic pump and / or means for adjusting   selectively the time interval for actuating said motor to drive said peristaltic pump, a comulative dose   per unit of time thus selectively modified.   5. Apparatus for intermittently dispensing a medical solution in small doses according to claim 4, characterized in that said peristaltic pump is a peristaltic pump of the roller typecomprenant rotor permanently fixed to a rotating drive shaft and a plurality 24% 95S   he equidistant rollers mounted on the rotor in a provision   mutual symmetrical with respect to the drive shaft.   6. Apparatus for intermittently dispensing   a medical solution in minimal doses according to   3 or 4, characterized in that said peristal pump   Tick is a peristaltic pump of the finger type.   7. Apparatus for intermittently dispensing   a medical solution in minute doses according to any   than claims 3 to 6, characterized by the fact that   further comprises a revolution detector associated with the shaft   rotary drive of said peristaltic pump for detecting   the number of turns of the tree so as to generate   detection pulses in proportion to the number of laps detected.   your. 8. Apparatus for intermittently dispensing   a medical solution in minute doses according to any   than claims 5 to 8, characterized in that   said motor driving the peristaltic pump is a motor step by step.