CO.sub.2 diagnostic monitor with rupturable container

• US 5,156,159 A
• Filed: 04/09/1990
• Issued: 10/20/1992
• Est. Priority Date: 10/11/1988
• Status: Expired due to Fees

• Current Assignee: University of Florida (State University System of Florida)
• Original Assignee: University of Florida (State University System of Florida)
• Inventors: Gravenstein, Nikolaus, Lampotang, Samsun, Gravenstein, Dietrich, Banner, Michael J., Gravenstein, Joachim S.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): NASSER, ROBERT L
• Application Number:
  US07/505,689
• Time in Patent Office: 925 Days
• Field of Search: 128/716, 128/719, 128/630, 128/772, 128/204.22, 128/205.23, 128/207.14, 128/200.26, 412/61, 236/133
• US Class Current: 600/532
• CPC Class Codes: A61M 16/0488 Mouthpieces; Means for guiding, securing or introducing the tubes guiding or introducing with laryngoscopes A61B1/267; holding devices on the body A61M25/02
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 2016/0413 with detectors of CO2 in exhaled gases
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)

Abstract

A diagnostic monitor checks the carbon dioxide (CO₂) content of a gas exiting a patient during endotracheal or esophageal intubation. A plurality of composition portions substantially change color in response to exposure to the carbon dioxide. The composition portions change color in response to different times of exposure to carbon dioxide. A magnifying or condensing lens may be positioned on the monitor to enhance viewing of the color change. The monitor may advantageously be made part of an intubation system through which the gases from a patient exit the patient. The differences in time of exposure needed to cause the color change may be accomplished by using semipermeable membranes having differing thicknesses, CO₂ permeabilities, and/or surface areas with each membrane corresponding to a particular one of the composition portions. An arrangement is provided whereby the monitor is automatically activated by the normal assembly steps of a patient breathing circuit.

Claims

1. A self-contained diagnostic monitor for screening the CO₂ content of a gas exiting a patient during endotracheal or esophageal intubation comprising:

a plurality of portions of compositions having an initial pH in solution above about 3.8 and which substantially change color in solution in response to exposure to CO₂, each of said composition portions being within a reservoir constructed substantially of a substantially transparent material for exteriorly viewing said color change;

an opening adapted for communication only with said gas exiting and entering said patient during endotracheal or esophageal intubation; and

a plurality of semipermeable membrane portions which are permeable to CO₂, each membrane portion separating at least one composition portion from said exiting and entering gases, and wherein said plurality of composition portions require a different time of exposure of CO₂ to effect said change in pH thereby causing said color change.

2. The monitor of claim 1 further comprising a solid inert substrate for each composition portion having a construction which enhances the viewing of said color change, each substrate maintaining the dimensions of a corresponding one composition portion substantially constant irrespective of the orientation of said monitor.

3. The monitor of claim 1 wherein each of said plurality of composition portions has a different initial pH.

4. The monitor of claim 1 wherein each composition portion is a liquid and is sealed in a fluid tight, removable wrapper to prevent dessication of each composition portion prior to use thereof in said intubation.

5. The monitor of claim 1 wherein at least one composition portion is non-liquid and further comprising means for introducing a liquid solvent to said composition prior to or during said intubation.

6. The monitor of claim 1 wherein said at least one composition is a buffered solution of bromothymol blue and phenolphthalein.

7. The monitor of claim 1 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having differing thicknesses.

8. The monitor of claim 1 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having differing CO₂ permeabilities.

9. The monitor of claim 1 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having differing surface areas.

10. In an endotracheal or esophageal intubation system containing means through which gases exit the patient during said intubation, the improvement comprising a self-contained diagnostic monitor for screening the CO₂ content of a gas exiting said patient during said intubation comprising:

a plurality of portions of a composition having an initial pH in solution above about 3.8 and which substantially change color in solution in response to exposure to CO₂, each of said composition portions being within a reservoir constructed substantially of a substantially transparent material for exteriorly viewing said color change in said at least one composition;

an opening adapted for communication only with said gases exiting and entering during said intubation; and

a plurality of semipermeable membrane portions which are permeable to CO₂, each membrane portion separating said at least one composition portion from said exiting and entering gases,

and wherein said plurality of composition portions require a different time of exposure to CO₂ to effect said change in pH thereby causing said color change.

11. The system of claim 10 further comprising a solid inert substrate for each composition portion having a construction which enhances the viewing of said color change, each substrate maintaining the dimensions of a corresponding one composition portion substantially constant irrespective of the orientation of said monitor.

12. The system of claim 11 wherein each of said plurality of compositions has a different initial pH.

13. The system of claim 10 wherein each composition portion is a liquid and said monitor is sealed in a fluid tight, removable wrapper to prevent dessication of each composition portion prior to use thereof in said intubation.

14. The system of claim 10 wherein at least one composition portion is non-liquid and further comprising means for introducing a liquid solvent to said composition prior to or during said intubation.

15. The monitor of claim 10 wherein said at least one composition is a buffered solution of bromothymol blue and phenolphthalein.

16. The system of claim 10 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having the same or differing thicknesses.

17. The system of claim 10 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having the same or differing CO₂ permeabilities.

18. The system of claim 10 wherein each of said plurality of composition portions is separated from said exiting gas by semipermeable membranes having the same or differing surface areas.

19. The system of claim 10 having a magnifying lens positioned thereon to enhance viewing of said color change.

20. The system of claim 10 having a condensing lens positioned thereon to enhance viewing of said color change.

21. In a method for monitoring the CO₂ content of gases exiting a patient during endotracheal or esophageal intubation, the improvement comprising contacting said exiting gases with a self-contained CO₂ diagnostic monitor integral with a breathing circuit piece, said monitor comprising:

1) a reservoir for containing at least one composition which substantially changes color in solution in response to CO₂, said reservoir having an opening adapted for communication only with said entering and exiting gases during said intubation; and

2) a semipermeable membrane which is permeable to CO₂, said membrane separating said at least one composition from said entering and exiting gases;

upon or immediately prior to contacting said exiting gases with the monitor, rupturing a container part of said monitor by connecting said breathing circuit piece to another breathing circuit piece such that a liquid will flow to adjacent said semipermeable membrane to activate the monitor; and

viewing said at least one composition.

22. In an endotracheal or esophageal intubation system containing a breathing circuit with means through which gases exit the patient during said intubation, the improvement comprising a self-contained diagnostic monitor for screening the CO₂ content of a gas exiting said patient during said intubation comprising:

1) a reservoir containing at least one portion of a composition which substantially changes color in solution in response to exposure to CO₂, said reservoir having an opening adapted for communication only with said gases exiting and entering during said intubation; and

2) a semipermeable membrane which is permeable to CO₂, said membrane separating said at least one composition from said exiting and entering gases, and

wherein said monitor is integral with a breathing circuit piece and includes a container part which is rupturable to allow a liquid within the container part to flow to adjacent said semipermeable membrane to activate the monitor;

said container part projecting from said breathing circuit piece such that said container part ruptures automatically when said breathing circuit piece is connected to another breathing circuit piece.

23. The system of claim 22 wherein said liquid is a solvent which activates a dry indicator disposed adjacent to said semipermeable membrane.

24. The system of claim 22 wherein said container part is integral with the adapter for an intubation tube.

25. The system of claim 24 wherein said container part is on an outer periphery of said adapter.