Electrically controlled intravenous infusion set

• US 4,038,982 A
• Filed: 12/03/1975
• Issued: 08/02/1977
• Est. Priority Date: 12/03/1975
• Status: Expired due to Term

• Current Assignee: B Braun Medical Incorporated (B. Braun Holding GmbH & Co. KG)
• Original Assignee: Burron Medical Products, Inc. (B. Braun Holding GmbH & Co. KG)
• Inventors: Thomas, Robert E., LeFevre, Robert J., Burke, George K., Turner, James W., Krohn, Peter L.
• Primary Examiner(s): Truluck, Dalton L.
• Application Number:
  US05/637,208
• Time in Patent Office: 608 Days
• Field of Search: 128/214 R, 128/214 C, 128/214 E, 128/214 F, 128/214.2, 128/DIG. 12, 128/DIG. 13, 251/123-125, 251/139, 251/141, 137/486, 137/487.5, 222/52, 222/59, 222/76, 222/420, 222/422, 73/194 E, 250/205, 250/222 PC, 250/564, 250/573, 356/102
• US Class Current: 604/65
• CPC Class Codes: A61M 5/1689 Drip counters
• CPC Class Codes: Y10S 128/13 Infusion monitoring
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

An electronically controlled intravenous infusion set of the gravity feed type having a flow path including a drip chamber and an internal valve for regulating flow through the set. Electromagnetic valve operating structure, positioned outside the IV set, controls the internal valve in response to an electronic control system. The electronic control system serves to open the valve to allow a drop to fall, and includes a control circuit. The control circuit includes an optical drop detector, associated with but positioned outside the drip chamber, which senses the falling drop and signals the control circuit to close the valve. The control circuit also includes a variable frequency clock and associated digital selectors for affording an attendant the ability to precisely select a desired drip rate. An alarm system, operating on digital principles, senses high drop rate or low drop rate conditions and, in response thereto, puts the control system into an alarm condition. The alarm system includes means for digitally adjusting the sensitivity thereof to provide high sensitivity at low drip rates but to decrease the sensitivity at higher rates so that premature alarm conditions are avoided.

Claims

1. An intervenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means within said passage, electromagnetic valve operating means associated with said valve means, drop detector means associated with said drip chamber for sensing drops falling therethrough, a variable frequency clock, digital switch means coupled to said clock for digitally selecting the output frequency of said clock, said variable frequency clock including a time base generator having a preset frequency, a variable modulus counter, said digital switch means being coupled to said counter for allowing an attendant to select the modulus thereof, and means for multiplying said preset frequency by the selected modulus of said counter for digitally selecting the output frequency of said clock, whereby a desired drop rate may be selected by manipulation of the digital switch means, switch means coupled to said valve operating means for controlling energization of said valve operating means, circuit means coupling said clock to said switch means for actuating said switch means to energize the valve operating means to open the valve at the rate selected by said digital switch means, said circuit means including means responsive to said drop detector means for deactuating said switch means to deenergize the valve operating means and thus enable said valve to close upon sensing of a drop by said drop detector means, and alarm means for detecting errors in the drop rate from that set on said digital switch means and entering an alarm mode in response thereto, said alarm means including means for preventing energization of said switch means whenever said alarm means is in said alarm mode.

2. An intervenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means within said passage, electromagnetic valve operating means associated with said valve means, drop detector means associated with said drip chamber for sensing drops falling therethrough, a variable frequency clock, digital switch means coupled to said clock for digitally selecting the output frequency of said clock, said variable frequency clock including a phase locked loop, a time base generator for supplying a preset frequency to said phase locked loop, a variable modulus counter in a feedback path between an output and a second input of said phase locked loop, said digital switch means being coupled to said variable modulus counter for selecting the modulus thereof, whereby the output frequency of said phase locked loop is equal to the base frequency at said first input multiplied by the selected modulus of said counter, switch means coupled to said valve operating means for controlling energization of said valve operating means, circuit means coupling said clock to said switch means for actuating said switch means to energize the valve operating means to open the valve at the rate selected by said digital switch means, said circuit means including means responsive to said drop detector means for deactuating said switch means to deenergize the valve operating means and thus enable said valve to close upon sensing of a drop by said drop detector means, and alarm means for detecting errors in the drop rate from that set on said digital switch means and entering an alarm mode in response thereto, said alarm means including means for preventing energization of said switch means whenever said alarm means is in said alarm mode.

3. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means within said passage, electromagnetic valve operating means associated with said valve means, drop detector means associated with said drip chamber for sensing drops falling therethrough, a variable frequency clock, digital switch means coupled to said clock for digitally selecting the output frequency of said clock, switch means coupled to said valve operating means for controlling energization of said valve operating means, circuit means coupling said clock to said switch means for actuating said switch means to energize the valve operating means to open the valve at the rate selected by said digital switch means, said circuit means including means responsive to said drop detector means for deactuating said switch means to deenergize the valve operating means and thus enable said valve to close upon sensing of a drop by said drop detector means, and alarm means for detecting errors in the drop rate from that set on said digital switch means and entering an alarm mode in response thereto, said alarm means including means for preventing energization of said switch means whenever said alarm means is in said alarm mode, said circuit means including bistable means having a first and second stable state, means responsive to the variable frequency clock for switching said bistable means to its first stable state, means responsive to the drop detector means for returning said bistable means to its second stable state, coupling means interposed between the bistable means and the switch means for energizing said switch means to open said valve when said bistable means is in its first stable state, said alarm means including means for disabling said coupling means and preventing further switching of said bistable means in said alarm mode, and alarm indicator means responsive to the state of said bistable means and said alarm means for indicating high rate and low rate errors in said alarm mode in dependence upon the last state of said bistable means.

4. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means within said passage, electromagnetic valve operating means associated with said valve means, drop detector means associated with said drip chamber for sensing drops falling therethrough, said drop detector means including light emitting means for illuminating at least a portion of said drip chamber, photosensor means opposed to said light emitting means for sensing the light from said light emitting means passing through said drop chamber, first circuit means driven by said photosensor means and responsive to the average light sensed by said photosensor means for regulating the intensity of said light emitting means, and second circuit means driven by said photosensor means and responsive to sudden transitions in light sensed by said photosensor means for producing a drop signal in response to the detection of a drop, whereby said photosensor serves the dual function of detecting drops and compensating for varying levels of illumination received thereby, a variable frequency clock, digital switch means coupled to said clock for digitally selecting the output frequency of said clock, switch means coupled to said valve operating means for controlling energization of said valve operating means, circuit means coupling said clock to said switch means for actuating said switch means to energize the valve operating means to open the valve at the rate selected by said digital switch means, said circuit means including means responsive to said drop detector means for deactuating said switch means to deenergize the valve operating means and thus enable said valve to close upon sensing of a drop by said drop detector means, and alarm means for detecting errors in the drop rate from that set on said digital switch means and entering an alarm mode in response thereto, said alarm means including means for preventing energization of said switch means whenever said alarm means is in said alarm mode.

5. The intravenous infusion set as set forth in claim 4, wherein the light emitting means is of the type emitting light in the non-visible spectrum, said photosensor means including means for preventing said photosensor means from responding to light in the visible spectrum, whereby said photosensor means is insensitive to ambient illumination.

6. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means within said passage, electromagnetic valve operating means associated with said valve means, drop detector means associated with said drip chamber for sensing drops falling therethrough, a variable frequency clock, digital switch means coupled to said clock for digitally selecting the output frequency of said clock, switch means coupled to said valve operating means for controlling energization of said valve operating means, circuit means coupling said clock to said switch means for actuating said switch means to energize the valve operating means to open the valve at the rate selected by said digital switch means, said circuit means including means responsive to said drop detector means for deactuating said switch means to deenergize the valve operating means and thus enable said valve to clsoe upon sensing of a drop by said drop detector means, and alarm means for detecting errors in the drop rate from that set on said digital switch means and entering an alarm mode in response thereto, said alarm means including means for preventing energization of said switch means whenever said alarm means is in said alarm mode, said alarm means including counter means for counting said errors, selector means responsive to the setting on said digital switch means for determining the number of errors required to enter said alarm mode, said selector means being so arranged and constructed to increase the number of errors required to enter the alarm mode with increasing drop rates set on said digital switch means.

7. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means in the passage for controlling flow of fluid in said passage, circuit means including a timer for opening the valve means at a preselected rate to cause the falling of drops at said rate, and drop detector means associated with said drip chamber and operative upon said circuit means for closing the valve in response to sensing of a drop falling through said drip chamber, said drop detector means including light emitting means at one side of the drip chamber for illuminating at least a portion of said drip chamber, photosensor means at the other side of the drip chamber in opposed relation to said light emitting means for sensing the light from said light emitting means passing through said drip chamber, first circuit means driven by said photosensor means and responsive to the average light sensed by said photosensor means for regulating the intensity of said light emitting means, and second circuit means driven by said photosensor means and responsive to sudden transitions in light as produced by a falling drop and sensed by said photosensor means for producing a drop signal in response to the detection of a drop, whereby said photosensor means serves the dual function of detecting drops and compensating for varying levels of illumination received thereby.

8. The intravenous infusion set as set forth in claim 7, wherein the light emitting means is of the type emitting light in the non-visible spectrum, said photosensor means including means for preventing said photosensor from responding to light in the visible spectrum, whereby said drop sensor is insensitive to ambient illumination.

9. The intravenous infusion set as set forth in claim 7, wherein said first circuit means further includes means for preventing said first circuit means from responding to sudden transitions in said light sensed by the photosensor means, whereby the intensity of said light emitting means is unaffected by detection of drops falling through said drip chamber.

10. The intravenous infusion set as set forth in claim 7, wherein said drop detector means includes a housing, said light emitting means including an array of individual light emitters mounted in said housing in a generally horizontal orientation to illuminate the width of said drip chamber, said photosensor means being mounted in said housing and set back from said drip chamber by a channel restricting the vertical field of view of said photosensor but providing a horizontal field of view encompassing the width of said drip chamber.

11. The intravenous infusion set as in claim 10, wherein an emitter supporting chassis is supported in said housing, said chassis including a plurality of sockets receiving respective light emitters and an opposed socket receiving a single photosensor, said array of light emitters focused on the photosensor across the drip chamber and through the channel.

12. The intravenous infusion set as in claim 11, wherein a further light emitter of the type emitting light in the visible spectrum is in said housing adjacent the array of light emitters for giving a visual indication of the operability of said drop detector means.

13. The intravenous infusion set as in claim 12, wherein said chassis comprises a plurality of secured together parts, including a top half and a bottom half, said halves having mating confronting recesses therein defining said sockets and channel.

14. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber and forming with said drip chamber a fluid flow passage, valve means in said passage for controlling flow of fluid therethrough, electromagnetic valve operating means associated with said valve, drop detector means associated with said drip chamber for sensing drops falling therethrough and producing drop pulses in response thereto, a variable frequency clock, drop rate selector means coupled to said clock for selecting the output frequency of said clock to produce clock pulses having a frequency equal to the desired drop rate, switch means coupled to said valve operating means for controlling said valve means, circuit means responsive to said clock pulses for energizing said switch means to open the valve means at the rate selected by said drop rate selector means, said circuit means including means responsive to said drop pulses for deenergizing said switch means to close said valve means upon sensing of a drop by said drop detector, whereby in normal operation clock pulses and drop pulses alternate, and alarm means responsive to said clock pulses and drop pulses for detecting errors in the form of non-alternation between said pulses, said alarm means including counter means for counting said errors, means associated with said counter means for selectively establishing a maximum number of allowable errors dependent upon the selected drop rate and entering an alarm mode in response to said counter means counting a number of errors exceeding said maximum number, and means for preventing energization of said switch means in said alarm mode.

15. The intravenous infusion as set forth in claim 14, wherein said counter means includes a binary counter for counting said drop pulses and said clock pulses, and circuit means operative upon said binary counter for resetting same in response to the alternate occurrence of clock pulses and drop pulses.

16. The intravenous infusion set as set forth in claim 14, wherein said counter associated means is a multiplexer responsive to the selected drop rate for increasing said maximum number with increasing selected drop rates, thereby to avoid premature entry of said alarm mode.

17. The intravenous infusion set as set forth in claim 16, wherein said drop rate selector includes digital switch means for digitally selecting the output frequency of said clock, said multiplexer having selector inputs coupled to said digital switch means for varying said maximum number in accordance with the drop rate selected by said digital switch means.

18. A drop detector for sensing drops falling through a drip chamber, said drop detector comprising in combination, a housing having means for supporting the drop detector adjacent a drip chamber, light emitting means supported in the housing for illuminating at least a portion of a drip chamber, photosensor means supported in the housing in opposed relation to said light emitting means for sensing the light from said light emitting means passing through a drip chamber, first circuit means connected with the light emitting means and photosensor means to be driven by said photosensor means and responsive to the average light sensed by said photosensor means for regulating the intensity of said light emitting means, and second circuit means connected to be driven by said photosensor means and responsive to sudden transitions in light as caused by a falling drop and sensed by said photosensor means for producing a drop signal in response to the detection of a drop, whereby said photosensor means serves the dual function of detecting drops and also compensating for gradually varying levels of illumination received thereby.

19. The drop detector as set forth in claim 18, wherein the light emitting means is of the type emitting light in the non-visible spectrum, said photosensing means including means for preventing said photosensor means from responding to light in the visible spectrum, whereby said drop sensor is insensitive to ambient illumination.

20. The drop detector as set forth in claim 18, wherein said light emitting means is of the type emitting radiation in the infrared spectrum, filter means carried by the housing in a position to be disposed between a drip chamber and the photosensor means for allowing the passing of infrared radiation to the photosensor means but blocking visible illumination therefrom, whereby said drop sensor is insensitive to ambient illumination.

21. The drop detector as set forth in claim 18, wherein said first circuit means further includes means for preventing said first circuit means from responding to sudden transitions in said light sensed by the photosensor means, whereby the intensity of said light emitting means is unaffected by detection of drops falling through a drip chamber.

22. The drop detector as set forth in claim 18, wherein said light emitting means includes an array of individual light emitters mounted in said housing in a generally horizontal orientation to illuminate the width of a drip chamber, said photosensor means being mounted in said housing in a position to be set back from a drip chamber associated therewith by a channel restricting the vertical field of view of said photosensor means but providing a horizontal field of view encompassing the width of said drip chamber.

23. An intravenous infusion set for use with a supply of intravenous fluid, said set comprising in combination, a drip chamber adapted to be connected to said supply, a length of IV tubing connected to said drip chamber, valve means within said tubing, electromagnetic valve operating means associated with said valve, drop detector means associated with said drop chamber for sensing drops falling therethrough and producing drop pulses in response thereto, a preset time base generator, a variable modulus counter, means coupling said time base generator and variable modulus counter for producing clock pulses at a base operating frequency equal to the preset frequency multiplied by the modulus of said counter, digital switch means connected with said counter for allowing an operator to select the modulus of said counter, bistable means having a first and a second stable state, means coupling said base operating frequency to said bistable means for switching said bistable means to its first stable state, means coupling the drop detector means to said bistable means for returning said bistable means to its second stable state in response to sensing of a drop, switch means coupled to said valve operating means for controlling said valve, coupling means interposed between said bistable means and switch means for energizing said switch means when said bistable means is in its first stable state, alarm means responsive to said base operating frequency pulses and said drop pulses and maintained in a first condition in response to alternation between said pulses, means for detecting errors in the form of non-alternation between said pulses and entering an alarm mode in response thereto, means operative in said alarm mode for deenergizing said coupling means for preventing further energization of said valve switch means, and alarm indicator means responsive to said bistable means and operative in said alarm mode to differentiate between and indicate high rate and low rate alarms.

24. The intravenous infusion set as set forth in claim 23, wherein said alarm means further includes counter means for counting said errors, multiplexing means coupling said counter means to said digital switch means to determine the number of counted errors required to enter said alarm mode, said multiplexing means serving to increase the deadband of errors necessary to enter the alarm mode at drip rates above a preselected minimum.

25. The intravenous infusion set as set forth in claim 24, wherein said counter means includes means for counting said clock pulses and drop pulses, and means for cyclically resetting said counter means in response to the return of said bistable means to said second stable state.