Device for monitoring and controlling an intravenous infusion system

• US 5,800,386 A
• Filed: 11/20/1995
• Issued: 09/01/1998
• Est. Priority Date: 11/25/1994
• Status: Expired due to Term

• Current Assignee: Francesco Bellifemine
• Original Assignee: Francesco Bellifemine
• Inventors: Bellifemine, Francesco
• Primary Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US08/559,839
• Time in Patent Office: 1,016 Days
• Field of Search: 604/65-67, 604/30-34, 604/49-50, 604/118, 604/151, 604/246-247
• US Class Current: 604/65
• CPC Class Codes: A61M 39/281 Automatic tube cut-off devices, e.g. squeezing tube on detection of air
• CPC Class Codes: A61M 5/1689 Drip counters

Abstract

A device for monitoring and controlling an intravenous infusion system includes a storage battery within a housing defining a drip chamber from which an intravenous infusion tube emerges which can be regulated by a shutoff device. The shutoff device is defined by first and second levers biased by respective first and second springs which are tripped through a microcontroller circuit responding to droplet sensing.

Claims

1. A device for monitoring and controlling an intravenous infusion system (1) comprising:

at least one electrical storage battery (2);

a housing (3) adapted to be closed about a drip chamber (17) from which a tube (14) of intravenous infusion system emerges;

a shutoff device (4) having an electromagnet (5) and being constructed and arranged to trip respective first and second levers (6,

     7) biased by respective first and second springs (9,

     8); and

electronic circuit means (12) comprising control means contained within microcontroller means (40), sensor means (28,

     29) for sensing droplets, generating droplet signals and transferring droplet signals to the microcontroller means (40) for either activating or not activating indicating means (13,

     33);

said electronic circuit means (12) further includes;

means for activating the sensor means (28,

     29), means for measuring the time interval between the passage of two consecutive droplets;

means for comparing the value of said time interval with a first reference time interval originally preset in the microcontroller means (40), to recognize whether the infusion underway is of the type classifiable as slow or fast;

means for calculating the arithmetic mean of the times elapsing between a number of successive droplets, the number of successive droplets being preset originally in the microcontroller means (40) on the basis of the type of infusion, such that for fast infusion this number is greater than the corresponding number preset for slow infusion;

said comparing means further compares said arithmetic time mean with the time interval between two successively delivered droplets to establish whether said time interval between two successively delivered droplets is equal to the value of the arithmetic mean plus or minus a first or second tolerance time interval originally preset in the microcontroller means (40);

means for setting one of a pre-alarm condition and an alarm condition depending on the extent of the difference between the value of the arithmetic time mean and the value of the time interval between the passage of two successive droplets;

means for activating the indicating means (13,

     33) both when in the pre-alarm condition and when in the alarm condition;

means for activating the shutoff device (4) only when in the alarm condition; and

means for interrupting the operation of the sensor means (28,

     29) during a second time interval included within the time interval between the passage of two successive droplets.

2. A device as claimed in claim 1, wherein the pre-alarm condition arises when, for at least three consecutive times, the difference between the value of the arithmetic time mean and the value of the time interval between the passage of two successive droplets is between 16% and 20% of the value of the arithmetic time mean.

3. A device as claimed in claim 1, wherein the alarm condition arises when, for at least three consecutive times, the difference between the value of the arithmetic time mean and the value of the time interval between the passage of two successive droplets exceeds 20% of the value of the arithmetic time mean, said alarm condition also arising in the case of delivery interruption.

4. A device as claimed in claim 1, wherein said sensor means (28, 29) are powered pulse-wise intermittently.

5. A device as claimed in claim 1, wherein said sensor means (28, 29) operate pulse-wise discontinuously, but uninterruptedly during the time interval between the passage of at least two successive droplets.

6. A device as claimed in claim 5, wherein said sensor means (28, 29) operate uninterruptedly after the delivery of groups of eight successive droplets.

7. A device as claimed in claim 1, wherein the time interval during which the operation of the sensor means (28, 29) is interrupted is determined on the basis of the following algorithm:

the value of the arithmetic mean of the times elapsing between a number of successive droplets less a value preset in the microcontroller (40).

8. A device as claimed in claim 7, wherein said microcontroller means (40) comprises an element (24) arranged to count said time interval and/or the activation times and/or the deactivation times of the indicating means (13, 33).

9. A device as claimed in claim 7, wherein said microcontroller means (40) continuously monitors the state of charge of said set of electrical storage batteries (2) and activates said indicating means (13, 33) when said state of charge falls below a level preset in the microcontroller (40).

10. A device as claimed in claim 1, wherein said sensor means (28, 29) are of an optical type.

11. A device as claimed in claim 10, wherein said sensor means (28, 29) are an emitter diode and a photodiode operating within the infrared spectrum.

12. A device as claimed in claim 1, wherein said sensor means (28, 29) include at least one transmitter element (28);

at least one receiver element (29) positioned on the same side as and adjacent to the transmitter element (28), with respect to a vertical axis which constitutes the trajectory undertaken by a droplet within the drip chamber (17); and

at least one reflector means (30) situated opposite to said receiver and transmitter elements (29, 28, respectively).

13. A device as claimed in claim 12, wherein said reflector means (30) is a concave mirror.

14. A device as claimed in claim 13, wherein said reflector means (30) is located on a base of a cavity (31).

15. A device as claimed in claim 1, wherein said indicating means (13, 33) are of optical and/or acoustic type.

16. A device as claimed in claim 15 wherein said indicating means of optical type are at least one two-colour LED (13).

17. A device as claimed in claim 16, wherein said two-colour LED (13) assumes one of the two colours when in the pre-alarm condition.

18. A device as claimed in claim 16, wherein said two-colour LED (13) assumes the other colour when in the alarm condition.

19. A device as claimed in claim 18, wherein said two-colour LEDs (13) are powered pulse-wise.

20. A device as claimed in claim 1, wherein said indicating means (13) of acoustic type is a pulse-wise operated piezoelectric buzzer (33).

21. A device as claimed in claim 1, including a first compartment (15) housing said storage battery (2);

a second compartment (16) within which there is provided a housing (3) which closes about said drip chamber (17) and in which said shutoff device (4) is housed;

a third compartment (18) housing the electromagnet (5) with which the shutoff device (4) is provided, the sensor means (28,

     29), the indicating means (13,

     33) and the electronic circuit (12), such that all the components are assembled within a single container having dimensions such as to result in a small overall size of the device (1).

22. A device as claimed in claim 21, wherein said shutoff device (4) second lever (7) has one arm (19) shorter than another arm (20);

a counteracting pin (22) which maintains one end (23) of the second lever (7) in the pre-loaded position;

said first lever (6) having an end on which there acts the electromagnet (5), against which said electromagnet (5) is held under the thrust of said second spring (9); and

a pushbutton (26) for resetting the shutoff device (4).

23. A device as claimed in claim 22, wherein said second lever (7) and first lever (6) are first class levers.

24. A device as claimed in claim 22, wherein a shorter arm (19) of said second lever (7) is substantially 7 mm in length.

25. A device as claimed in claim 22, wherein a longer arm (20) of the second lever (7) is at least substantially 16 mm in length.

26. A device as claimed in claim 25, wherein said shutoff device (4) can apply a force of at least 20 newtons to the tube (14).

27. A device as claimed in claim 22, wherein said electromagnet (5) is operated by at least two successive current pulses.

28. A device as claimed in claim 26, wherein when electric current passes through the electromagnet (5), an end (36) of the first lever (6) is moved by a rod (25) rigid with a moving core of the electromagnet (5), and with it there also moves the counteracting pin (22) to release the second lever (7), and end (32) of said second lever (7) throttles the tube (14) of the system.

29. A device as claimed in claim 28, including a permanent magnet (27) located at an end of the electromagnet (5) distant from an end from which the rod (25) travels outwards from said electromagnet (5), on termination of its return travel said rod (25) at least partially traversing said permanent magnet (27) so that said permanent magnet (27) causes the rod (25), rigid with the moving core of the electromagnet (5), to return to its initial position after the electromagnet (5) has operated.

30. A device as claimed in claim 28, including an idle travel portion before the action of the electromagnet (5) causes the rod (25) to strike the first lever (6) such that the rod (25) has a hammer effect on an end (36) of the first lever (6).

31. A device as claimed in claim 1, wherein the walls of the housing (3) are of dark and/or opaque color.

32. A device as claimed in claim 1, wherein said storage battery (2) includes at least one storage battery element rechargeable by means external to the device (1).

33. A device as claimed in claim 1, including a capacitor (37) which charges at the moment of activation of the device (1) and transfers energy to the electromagnet (5) should the consumed current be high in relation to the capacity of the storage battery (2).

34. A device for monitoring and controlling an intravenous infusion system (1) comprising:

at least one electrical storage battery (2);

a housing (3) adapted to be closed about a drip chamber (17) from which a tube (14) of the intravenous infusion system emerges;

at least one geared motor (42) powered by direct current from the storage battery (2);

a cam (44) connected to the geared motor (42);

a lever (45) biased by a torsion spring (46);

electronic circuit means (12) comprising control means contained within at least one microcontroller means (40);

sensor means (28,

     29) for sensing droplets, generating droplet signals and transferring droplet signals to the microcontroller means (40) for either activating or not activating indicating means (13,

     33);

means for generating electrical signals for controlling the operation of the geared motor (42) such that said geared motor (42) acts, via the cam (44), on the lever (45) which consequently continuously regulates the opening and closing of the tube (14) and hence the rate of infusion of the solution to be administered.

35. A device as claimed in claim 34, wherein said electrical signals generating means includes a keypad and/or a bar code.

36. A device as claimed in claim 34, wherein said electrical signals generating means includes reader means defined by laser diodes.

37. A device as claimed in claim 34, wherein said lever (45) is a first class lever having a fulcrum (52) closer to the point of application of the force which throttles the tube (14) than a point of application of the force impressed by said cam (44).

38. A device as claimed in claim 34, wherein said lever (45) is provided with a protuberance (47) on which said cam (44) acts.

39. A device as claimed in claim 38, wherein said cam (44) engages the protuberance (47) of said lever (45).

40. A device as claimed in claim 34, wherein said electrical signals generating means includes a dedicated enabling means to prevent possible tampering and/or adjustment.

41. A device as claimed in claim 40, wherein said dedicated enabling means includes a pulse code.

42. A device as claimed in claim 40, wherein said dedicated enabling means includes a jack plug.

43. A device as claimed in claim 34, wherein said electronic circuit means (12) includes a memory device to maintain the data inserted into said electrical signals generating means.