GB2085596A - Esophageal Probe and Sheath Therefor - Google Patents

Abstract

An esophageal probe 10 includes a removable, reusable temperature transducer 26 encased within a flexible lumen 12, the lumen also being adapted for use as part of an acoustic esophageal stethoscope 16, 18, 20, 22, 24. The temperature transducer includes a cable 30 having a coating of high lubricity material such as polytetrafluoroethylene. The lower portion of the cable and the transducer are passed into the lumen through a flexible seal 46 attached to a fitting 32 at the upper end of the lumen. The fitting includes a branch for the attachment of an acoustical ear piece or electrical microphone. <IMAGE>

Description

SPECIFICATION Esophageal Probe and Sheath Therefor The invention concerns apparatus for measuring the temperature and monitoring the heart and lung sounds of the human body. More specifically, the invention concerns an esophageal probe which includes a removable, reusable temperature transducer and the esophageal portions of an acoustic esophageal stethoscope.

Esophageal stethoscopes embodying some means for measuring body temperature have been known for several years. One example of such a device is shown in U.S. Patent No.

3,951,136 issued to Wall, in which a temperature transducer is positioned near the bottom of a balloon-type esophageal stethoscope. The stethoscope or sheath and the temperature transducer in such devices are permanently joined to each other. This unitary construction makes it necessary either to discard the entire device after only a single use or to attempt to resterilize the device with attendant risk of damage to the electrical temperature transducer. Presumably some devices would survive the resterilization in condition for reuse, but the prevailing practice is to eliminate resterilization altogether and just discard the unit following its first use. A need has existed for such a device in which at least a portion of the device is reusable without being resterilized, thereby reducing costs and senseless waste.

An object of the invention is to provide an improved esophageal temperature probe in which the temperature measuring transducer is readily removable from the probe for subsequent reuse.

Another object of the invention is to provide such a probe which can be simultaneously used as an acoustic esophageal stethoscope.

A further object of the invention is to provide an improved, inexpensive and disposable sheath for an esophageal temperature transducer, the sheath also being adapted for use alone as an acoustic esophageal stethoscope.

These objects of the invention are given only by way of example. Thus, other desirable objectives and advantages inherently achieved by the disclosed structure may occur or become apparent to those skilled in the art. Nevertheless, the scope of the invention is to be limited only by the appended claims.

According to one aspect of the present invention there is provided an esophageal temperature probe, comprising: a flexible lumen adapted for insertion into the esophagus; first means for closing the lower end of said lumen to prevent entry of bodily fluids into the interior thereof; a temperature measuring transducer positioned adjacent said lower end, said transducer comprising an electrical cable, said cable extending upward through the interior space of said lumen and past the upper end of said lumen; and second means located at said upper end of said lumen for providing a seal surrounding said cable, said seal being adapted to permit said transducer and cable to be inserted into and withdrawn from said lumen through said seal.

According to another aspect of the present invention there is provided a sheath for an esophageal probe, comprising: a flexible lumen adapted for insertion into the esophagus, first means for closing the lower end of said lumen to prevent entry of bodily fluids into the interior thereof; and second means located at the upper end of said lumen for providing a seal surrounding an elongated instrument to be inserted into the sheath, said seal being adapted to permit the elongated instrument to be inserted into and withdrawn from said lumen through said seal.

The lumen may comprise a plurality of radially extending holes spaced about its circumference and along a portion of its length in the region of said lumen which is to be inserted into the esophagus. The first means may comprise a flexible tubular diaphragm extending along and surrounding said lumen at the location of said holes. The second means may comprise a fitting adapted to receive said upper end, said fitting having an interior bore through which said cable passes, said seal being adapted to cooperate with said fitting to close the upper end of said interior and to surround said cable. The fitting may also have a bore branching from said interior bore for transmitting pressure variations from the interior space of said lumen to external means for monitoring heart and lung sounds.A portion of said cable or instrument within said lumen may comprise an exterior covering of a material having a high degree of lubricity, said seal comprising an elastomeric injection cap through which said transducer and cable or instrument may be passed.

The sheath for the temperature transducer also may be used, by itself or in combination with the temperature transducer, as an esophageal stethoscope. The branch bore of the fitting attached to the upper end of the lumen may be connected to an acoustic earpiece or to an electrical microphone when a temperature tranducer is in place in the sheath. Or, when temperature monitoring is not required, the branch bore may be used for connection to an acoustic earpiece and an electrical microphone may be attached in place of the injection cap.

Because the sheath can be made from relatively inexpensive materials, it may be discarded following each use; whereas, the more expensive temperature transducer and cable may be retained for repeated use with new, sterile sheaths.

As esophageal probe and a sheath for an esophageal probe, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a plan view of an assembled esophageal probe according to the invention; Figure 2 shows an enlarged, partially sectioned view of the lower end of the probe, indicating the relative positions of the lumen, tubular diaphragm, temperature transducer and cable; and Figure 3 shows an enlarged exploded, partially sectioned view of the upper end of the sheath indicating the relative position of the lumen, fitting and injection cap.

Referring simultaneously to Figures 1 to 3, those skilled in the art will understand the structure of an esophageal probe 10 made in accordance with the invention. A flexible plastic tube or lumen 12 is closed at its lower end 14 by a thin tubular diaphragm 16 having a bulbous lower end 18, a lower cuff 20 extending upward from end 1 8 and an upper cuff 22. Diaphragm 1 6 may be made using conventional blow-moulding or mandrel-dipping techniques. It both seals the lower end of lumen 12 and transmits heart and lung sounds to the interior of lumen 12, via a plurality of radially extending openings 24. The structure thus far described has been known in the art for several years.

Within lumen 12 is located a temperature transducer 26 which is positioned in close proximity to the inside surface of bulbous end 18.

Transducer 26 may comprise a conventional temperature sensing element such as a thermistor, a thermocouple or a combination of elements. To protect the temperature sensing elements from damage during assembly and disassembly of probe 10, a corrosion resistant sheath 28 is potted around the sensing elements.

Sheath 28 may be made from any suitable metal plastic having good corrosion resistance and thermal conductivity. A cable 30 extends from transducer 26 to a point outside a plastic fitting 32 which is attached to the upper end 34 of lumen 12. Preferably, cable 30 is provided with an exterior cover or coating of a material having a high degree of lubricity, such as polytetrafluoroethylene.

Fitting 32 comprises a molded cylindrical body 36 having a central bore 38 sized so that transducer 26 and cable 30 may be easily threaded through the fitting. The lower end of fitting 32 is provided with a male luer attachment 40 over which upper end 34 is glued. A stop shoulder 42 limits the penetration of Luer attachment 40 into lumen 12. At the upper end of fitting 32 a circumferential lip 44 is provided for removably mounting a molded elastomeric injection cap 46. Preferably, cap 46 is provided with a minute central aperture, not illustrated, made by passing means such as a 14-gauge needle through the top wall of the cap. This tiny aperture can expand to permit transducer 26 and cable 30 to pass through the cap and yet provide an effective seal around the cable when the probe is in use.

Fitting 32 preferably also includes a branch conduit 48 having a further male Luer attachment 50 and a bore 52. An acoustical ear piece or electrical microphone may be attached at 50 when cable 30 is present in cap 46 and bore 38.

If the sheath made up from lumen 12, diaphragm 16 and fitting 32 is used alone as an esophageal stethoscope, then an acoustic earpiece may be attached at 50 and an electrical microphone at 44. Cable 30 terminates at a stainless steel transition piece 54 which joins it to a heavier cable 56 designed to extend from the area of the patient to appropriate monitoring equipment (not shown) into which it is plugged using a connector 58. If desired, transition piece 54 may comprise a quick disconnect.

To assembly the entire probe, diaphragm 1 6 and fitting 32 are glued to their respective ends of lumen 12. Transducer 26 and cable 30 are pushed through cap 46 which then is moved upn cable 30 to just below transition piece 54.

Transducer 26 and cable 30 are then threaded down through fitting 32 until transducer 26 just barely contacts bulbous end 18. Injection cap 46 is moved back down cable 30 and snapped over circumferential lip 44 to provide a seal between cable 30 and fitting 32. An acoustic earphone or electrical transducer may be connected at 50.

Following use, the sheath comprised of lumen 12, diaphragm 16 and fitting 32 is slipped off the cable and transducer assembly and then discarded, after which the cable and transducer may be used again.

The invention is particularly suited for use in esophageal measurement of temperature in human beings, with or without accompanying use as a stethoscope, and also may be used in similar manner with animals. The disposable sheath may be used alone as a stethoscope.

Claims (19)

Claims

1. An esophageal temperature probe, comprising: a flexible lumen adapted for insertion into the esophagus; first means for closing the lower end of said lumen to prevent entry of bodily fluids into the interior thereof; a temperature measuring transducer positioned adjacent said lower end, said transducer comprising an electrical cable, said cable extending upward through the interior space of said lumen and past the upper end of said lumen; and second means located at said upper end of said lumen for providing a seal surrounding said cable, said seal being adapted to permit said transducer and cable to be inserted into and withdrawn from said lumen, through said seal.

2. A probe according to Claim 1, wherein said lumen comprises a plurality of radially extending holes spaced about its circumference and along a portion of its length in the region of said lumen which is to be inserted into the esophagus.

3. A probe according to Claim 2, wherein said first means comprises a flexible tubular diaphragm extending along and surrounding said lumen at the location of said holes.

4. A probe according to any one of the preceding claims, wherein said second means further comprises a bore for transmitting pressure variations transmitted to the interior space of said lumen from the lungs and heart to external means for monitoring heart and lung sounds.

5. A probe according to any one of the preceding claims, wherein said second means comprises a fitting adapted to receive said upper end, said fitting having an interior bore through which said cable passes, said seal being adapted to cooperate with said fitting to close the upper end of said interior and to surround said cable.

6. A probe according to Claim 5, wherein said fitting also has a bore branching from said interior bore for transmitting pressure variations from the interior space of said lumen to external means for monitoring heart and lung sounds.

7. A probe according to any one of the preceding claims, wherein at least the portion of said cable within said lumen comprises an exterior covering of a material having a high degree of lubricity and said seal comprises an elastomeric injection cap through which said transducer and cable may be passed.

8. A probe according to any one of the preceding claims, further comprising an electrical connector means attached to said cable for connecting said transducer to external means for monitoring temperature.

9. A probe according to any one of the preceding claims, wherein said transducer is encased in a corrosion-resistant sleeve.

10. A sheath for an esophageal probe, comprising: a flexible lumen adapted for insertion into the esophagus; first means for closing the lower end of said lumen to prevent entry of bodily fluids into the interior thereof; and second means located at the upper end of said lumen for providing a seal surrounding an elongated instrument to be inserted into the sheath, said seal being adapted to permit the elongated instrument to be inserted into and withdrawn from said lumen, through said seal.

11. A sheath according to Claim 10, wherein said lumen comprises a plurality of radially extending holes spaced about its circumference and along a portion of its length in the region of said lumen which is to be inserted into the esophagus.

12. A sheath according to Claim 11, wherein said first means comprises a flexible tubular diaphragm extending along and surrounding said lumen at the location of said holes.

13. A sheath according to any one of Claims 10 to 12, wherein said second means further comprises a bore for transmitting pressure variations transmitted to the interior space of said lumen from the lungs and heart to external means for monitoring heart and lung sounds.

14. A sheath according to any one of Claims 10 to 13, wherein said second means comprises a fitting adapted to receive said upper end, said fitting having an interior bore through which said instrument passes, said seal being adapted to cooperate with said fitting to close the upper end of said interior bore and to surround said instrument.

15. A sheath according to Claim 14, wherein said fitting also has a bore branching from said interior bore for transmitting pressure variations from the interior space of said lumen to external means for monitoring heart and lung sounds.

16. A sheath according to any one of Claims 10 to 15, wherein said seal comprises an elastomeric injection cap through which said instrument may be passed into said lumen.

17. A sheath according to Claim 16, wherein said upper end of said interior bore is provided with means for removably mounting said injection cap.

18. An esophageal temperature probe substantially as hereinbefore described with reference to the accompanying drawings.

19. A sheath for an esophageal probe, said sheath being substantially as hereinbefore described with reference to the accompanying drawings.