FR2544987A1 - Semi-automatic insulin pump for patient in bed - Google Patents

Abstract

This pump is of the type comprising, disposed on a framework, an injection syringe and its stationary support, an electrical "step" motor and its pulse generator, coupled to a leading screw via a gearing, and an element which can move along this leading screw to which it is connected by a clutch and which is hitched to the piston of the syringe so as to cause, when it is moved in one direction, injection, into the body of the patient, of the product contained in the syringe. There are provided, on the one hand, three preadjusted frequencies of the pulse generator, each of which can be selected by a control member, such as a push button 23a, 23b, 23c, which can be reached by the patient or nurse, and each of which corresponds to a predetermined small delivery of basal insulin and, on the other hand, a fourth frequency which can also be selected by a control member corresponding to a high delivery of prandial insulin and intended to prevent the onset of hyperglycaemia, the control assembly being arranged so that the delivery of basal insulin is interrupted when the delivery of prandial insulin is started, and so that it is reestablished when the latter ceases.

Description

SEMI-AUTOMATIC INSULIN PUMP FOR SICK LAYER
The present invention relates to a semi-automatic insulin pump for lying patients. There are known pumps used for injecting a product into a human organism comprising, arranged on a frame, an injection syringe and its fixed support, a "stepping" electric motor and its pulse generator, coupled to a lead screw by means of a reduction gear, a mobile assembly along this lead screw to which it is linked by a clutch and which is coupled to the piston of the syringe so as to cause, by its displacement in one direction, the injection into the patient's body of the product contained in the syringe.

 Pumps of this type, although satisfactory, have the disadvantage of not allowing easy adjustment of the injection rate, for example by the patient himself or the nurse.

 In addition, studies and tests have made it possible to discover that for the treatment of blood sugar levels, three different rates were sufficient to allow adaptation of the permanent insulin infusion, called basal insulin, that is to say that intended to correct Interprandial blood sugar fluctuations meet the needs of virtually all sleeping diabetics.

 It is on the basis of this observation that the insulin pump according to the invention was developed, which is of the aforementioned type and in which there are provided, on the one hand, three preset frequencies of the pulse generator, each of which is selectable by a control member, such as a push button, accessible by the patient or the nurse and each of which corresponds to a predetermined low rate of basal insulin and, on the other hand, a fourth preset frequency linked to a preset timer, also selectable by a control device, such as a push button, accessible by the patient or nurse, and corresponding to a high flow of insulin limited in time, or meal insulin, and intended to prevent the glycemic increases following the absorption of the meals, the control assembly being, in addition, arranged so that the selected flow of basal insulin is interrupted when the flow of meal insulin is started and so that it is again forgot when the meal insulin flow stopped.

 This pump therefore allows the patient or nurse to select their basal insulin flow themselves according to the regular tests to which they are required during the day. It also allows it to trigger high flow at mealtimes.

 Preferably, the means for limiting the flow of mealtime insulin over time consist of a countdown clock, the countdown time of which results from the amount of insulin displayed by the patient or the nurse, expressed in units d insulin and translated in time by the clock taking into account the constant flow of the pump.

 According to yet another very interesting characteristic of the invention making it possible to take into account the receptivity of the patient towards insulin, means are provided to make it possible to slightly reduce the flow of basal insulin, whatever else the selected flow rate, these means being controlled by a two-position switch accessible by the patient or the nurse.

 According to another characteristic of the invention allowing very rapid intervention by medical personnel in the event of a diabetic coma, a fifth preselected frequency is provided corresponding to a very high flow of insulin required in the event of a diabetic coma, selectable with the using a control member such as a push button, not accessible to the patient.

 In any case, the invention will be clearly understood with the aid of the description which follows with reference to the appended schematic drawing showing by way of nonlimiting example, an embodiment of this pump.

Figure 1 is a perspective view,
Figure 2 is a rear view,
Figure 3 is a schematic view illustrating its operation.

As shown in particular in Figure 3, this pump is of the type comprising a syringe (2) whose body (2a) is held fixed by collars (3) supported by an element (4) integral with the pump frame. This syringe (2) whose body (2a) contains the product to be injected is equipped with a flexible tube (5) itself
equipped at its free end with an injection needle (6) intended to be placed on the patient.

 In this pump which is of a known type, an electric motor (7) is provided "step by step" connected by means of a reduction gear (8) to a mother screw (9) immobilized axially with respect to to the frame of the apparatus, that is to say, with respect to the aforementioned element (4) and to a bracket (11) integral with this element (4) and on which the motor (7) is fixed and its reducer (8). A unit (12) movable along this lead screw (9) is carried by a column (13) parallel to the lead screw and by a tube (14) enveloping the lead screw (9). The column (13) and the tube (14) pass through a block (15) secured to the frame of the apparatus, that is to say of its element (4) through guide bearings (16). (13) and the tube (14) are integral, at their opposite ends, with the movable assembly (12) of a spacer or head (17) provided with an extension (17a) - intended to be coupled to the piston ( 2b) of the syringe (2). As clearly shown in Figure 3, the movable assembly (12) is normally engaged with the mother screw (9) by means of a clutch member (18) movable transversely relative to the mother screw (9) and normally kept engaged against this lead screw by a return spring (1 9). This arrangement allows disengagement of the member (18) relative to the mother screw (9) in the event that a retaining force greater than a predetermined threshold prevents movement of the piston (2b) of the syringe (2) in the direction of arrow (21).

The operation of this pump is as follows
The electric motor (7) drives the lead screw (9) in rotation in the direction corresponding to the displacement # of the mobile assembly (12) in the direction of the arrow (21). During this movement, the mobile assembly (12) carries with it the column (13) and the tube (14), the spacer (17), and consequently, the piston (2b) of the syringe (2) , thereby causing the insulin it contains to be injected through the tube (5) and the needle (6).

 The frequency of the pulses transmitted to the electric motor (7) obviously determines the flow of insulin injected from the syringe (2). It is therefore easily understood that by adjusting these pulses, it is possible to adjust the insulin flow rate. To this end, the supply of the "step-by-step" electric motor (7) is carried out through a pulse generator (22).

 As shown in Figures 1 and 2, unlike pulse generators used with known pumps of this type, in the pump according to the invention, there are provided three preset frequencies each of which is selectable by a push button (23a, 23b, 23c), corresponds to a determined rate of basal insulin; for example, the frequency controlled by the push button (23a) corresponds to a basal insulin flow of 0.5 unit per hour, the push button (23b) corresponds to a flow of 1 unit per hour and finally, the button pusher (23c) corresponds to a flow rate of 3 units per hour.

 To be accessible to the patient or the nurse, these three push buttons (23a, 23b, 23c) are placed on the front of the device, like the start switch (24).

 As previously mentioned, the nurse's patient selects the basal insulin flow based on the results of the tests that the patient undergoes several times a day so that he can determine which of these three flow rates is best suited to his rate of blood sugar of the moment.

 In an improved embodiment of the invention making it possible to take into account the receptivity of the patient towards insulin, a two-position switch (28) is provided, allowing the basal insulin flow rate to be slightly reduced, whatever the flow rate selected by one of the three pushbuttons (23a, 23b or 23c). This switch is placed in a location making it easily accessible by the patient or nurse; for example, by placing this switch (28) in its position of slowing down the basal insulin flow, the flow controlled by the push button (23a) goes from 0.5 unit per hour to 0.4 unit per hour, that ordered by the push button (23b) goes from 1 unit per hour to 0.8 unit per hour and that controlled by the push button (23c) goes from 3 units per hour to 1.5 units per hour.

 To also allow the patient or nurse to adapt the insulin flow to the needs made necessary by the ingestion of meals, so-called prandial insulin flow, there is also a fourth preset frequency corresponding to a high flow d insulin and selectable using a push button (25). With the means for selecting this third frequency, there are associated time-out means simply constituted by a clock (26), allowing the patient or the nurse to display the time during which this flow of mealtime insulin must be maintained. . In reality, it suffices #ffit the patient or nurse to display the number of units of insulin required according to the nature of the meal considered, the clock translating in time this number- units to take into account constant pump flow.

 Means not shown in the drawing are associated with the pulse generator (22) for controlling the stopping of the basal insulin flow rate when starting the mealtime insulin flow rate and vice versa, controlling the start up of the flow rate of basal insulin when stopping the meal insulin flow.

 As we can see, with this pump, the patient can administer himself the insulin injections or infusions that his condition requires without absolute necessity of constant intervention on the part of the medical personnel who, therefore, finds himself released for other duties.

 As shown in FIG. 2, the pulse generator advantageously comprises a fifth preset frequency corresponding to a very high flow of insulin capable of being used during a diabetic coma of the patient. In this case, the intervention of medical personnel is compulsory and this is the reason why the control push button (27) of this frequency is arranged on the rear face of this pump. Pressing the push button (27) cancels all other prior commands. Each control push button is associated with a control indicator light designated by the same reference with the sign (').

 As is obvious and as follows from the above, the invention is not limited to the only embodiment of this pump which has been described above by way of nonlimiting example; on the contrary, it embraces all of its variant embodiments.

Claims (6)

 1. - Insulin pump - semi-automatic for the lying patient of the type comprising, arranged on a frame, an injection syringe (2) and its fixed support (3, 4), a "step by step" electric motor (7) and its pulse generator (22), coupled to a mother screw (9) by means of a reduction gear (8), an assembly (12) movable along this mother screw (9) to which it is linked by a clutch (18) and which is coupled to the piston (2b) of the syringe (2) so as to cause, by its displacement in one direction, the injection, into the patient's body, of the product contained in the syringe (2), characterized in that, on the one hand, three preset frequencies of the pulse generator are provided, each of which is selectable by a control member, such as a push button (23a, 23b, 23c), accessible by the patient or the nurse and each of which corresponds to a predetermined low rate of basal insulin and, on the other hand, a fourth preset frequency linked to a preset delay ( 26), this fourth frequency also being selectable by a control member, such as a push button (25), accessible by the patient or the nurse, and corresponding to a high flow of insulin limited in time, or prandial insulin, and intended to prevent glycemic increases following the absorption of meals, the control assembly being, in addition, - arranged so that the selected flow of basal insulin is interrupted when the flow of mealtime insulin and to be re-established when the mealtime insulin flow stops.  2. An insulin pump according to claim 1, characterized in that the means (26) for delaying or limiting in time the flow of mealtime insulin consist of a clock (26) with countdown and whose time to count down results from the quantity of insulin displayed by the patient or the nurse, expressed in units of insulin and translated into time by the clock, taking into account the constant flow delivered by the pump.  3. - Insulin pump according to claim 2, characterized in that the three preset basal insulin rates are respectively 0.5 - 1 and 3 units per hour.  4. - Insulin pump according to any one of the preceding claims, characterized in that means are provided to allow a slight reduction in the flow of basal insulin, regardless of the flow selected, these means being controlled by a two-position switch (28) accessible by the patient or the nurse.  5. - Insulin pump according to claim 5, characterized in that the slowed rates corresponding to the three preset rates of basal insulin are respectively 0.4 - 0.8 and 1.5 units per hour.  6. - Insulin pump according to any one of the preceding claims, characterized in that there is provided a fifth preselected frequency corresponding to a very high insulin flow rate necessary in case of diabetic coma, selectable using a control organ, such as a push button (27), not accessible to the patient.