US20040171942A1 - Esophageal balloon catheter device - Google Patents

Abstract

An esophageal catheter device including a catheter with a balloon pressure sensor affixed to an exterior surface of the catheter, and a stylet assembly including a stylet for providing appropriate rigidity to the catheter to aid insertion in the esophagus and a port for removably mounting a pressure transducer.

Description

FIELD OF THE INVENTION
• The present invention relates to a device that provides a conduit through which intra-thoracic pressures can be monitored and measured. More particularly, the present invention relates to an improved esophageal balloon catheter device that is used to obtain esophageal pressure data for evaluating, treating and diagnosing patients with various respiratory conditions and diseases.[0001]
BACKGROUND OF THE INVENTION
• Esophageal balloon catheter devices are commonly used as a research or clinical tool in the study of lung mechanics. Specifically, many investigators have utilized esophageal balloons to characterize the mechanical properties of the lung in both health and in disease as well as in determining the work or effort of breathing.[0002]
• More recently, esophageal balloon catheter devices have been used as part of monitoring systems for diagnosing sleep disorders, the clinical management of ventilator patients, as well as a part of pulmonary function systems in the measurement of lung mechanics.[0003]
• Typical esophageal balloon catheter devices employ an air-containing balloon sealed over the distal or near distal end of a catheter that transmits balloon pressure to a pressure transducer attached to the proximal end of the catheter. A pressure transducer in this context converts mechanical energy (balloon pressure) into electrical signals and units of measurement. The balloon of the catheter is usually positioned in the lower or middle third of the esophagus to monitor esophageal pressure to determine lung compliance and respiratory effort. As is known; during inhalation the pressure in the esophagus and thorax decreases, while it increases in the viscera below the diaphragm and during exhalation the pressure in the esophagus and thorax increases while it decreases in the viscera below the diaphragm[0004]
• The catheter used in these devices is sometimes constructed to be stiff and rigid enough to allow insertion through the nasal passage and down into the esophagus. A serious disadvantage of these devices is that they are uncomfortable to patients being monitored to an extent that the pressure data may be affected as well as the patient's ability to sleep. The catheter used in these devices may also be constructed to be limp and flaccid to provide comfort during overnight esophageal pressure testing. However, the limp and flaccid nature of the catheter makes it virtually impossible to insert it into the esophagus. Accordingly, such a catheter device includes a removable stylet assembly, which consists of a wire that is inserted into the lumen of the catheter at the proximal end thereof to stiffen the catheter so that it can be inserted into the esophagus and the balloon properly positioned therein. Once the balloon of the catheter device is positioned in the esophagus, the stylet assembly needs to be removed so the pressure transducer can be attached to the proximal end of the catheter.[0005]
• A major disadvantage of these devices is that it is very difficult to position the balloon correctly in the esophagus. There is an advantage in being able to monitor esophageal pressure oscillation while positioning the balloon in the esophagus. This is possible with the stiffer more rigid catheters but not with the more comfortable soft and flaccid catheters. Once the stylet is removed and the pressure transducer attached, it is often discovered that the balloon is not properly positioned in the esophagus. Because the catheter is so soft and flaccid this necessitates removing the pressure transducer and reinserting the stylet into the catheter to stiffen it so that the position of the balloon can be corrected. Unfortunately, reinserting the stylet assembly into the catheter is extremely dangerous as it can puncture the catheter and the esophagus.[0006]
• Accordingly, there is a need for an improved esophageal balloon catheter device, which is soft and flaccid for comfort and yet allows for monitoring esophageal pressure oscillation to aid proper positioning of the balloon. Such a device would avoid the need for removal of the stylet to attach the pressure transducer and the subsequent risk of reinserting the stylet assembly for balloon repositioning.[0007]
SUMMARY OF THE INVENTION
• An esophageal catheter device comprises a catheter with a balloon as pressure sensor affixed to an exterior surface of the catheter, and a stylet assembly including a stylet for preventing bending and flexing of the catheter during insertion in the esophagus and a port for removably attaching a pressure transducer.[0008]
BRIEF DESCRIPTION OF THE DRAWINGS
• The advantages, nature, and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to be described in detail in connection with accompanying drawings wherein:[0009]
• FIG. 1 is an elevational view of an esophageal balloon catheter device according to an exemplary embodiment of the present invention;[0010]
• FIG. 2 is a sectional view of a balloon air pressure sensor according to an exemplary embodiment of the catheter device of the present invention;[0011]
• FIG. 3 is a side elevational view of an exemplary stylet transducer coupler assembly according to an exemplary embodiment of the catheter device of the present invention;[0012]
• FIG. 4 is a side elevational view showing a pressure transducer mounted to the transducer port of the coupler assembly; and[0013]
• FIG. 5 is a side elevational view showing a pressure transducer mounted to a hub connector of the catheter device.[0014]
DETAILED DESCRIPTION OF THE INVENTION
• Referring to the drawings wherein like reference numerals identify similar or like elements throughout the several views and initially to FIG. 1, there is shown an esophageal[0015]balloon catheter device10 according to an exemplary embodiment of the invention. Thecatheter device10 generally comprises acatheter12, apressure sensor14 sealingly affixed to the exterior surface of thecatheter12 in a conventional manner, and a stylettransducer coupler assembly16 having atransducer port18 for mounting a pressure transducer which may be used for correctly positioning thepressure sensor14 of the device in the esophagus. The ability to attach a pressure transducer to thecoupler assembly16 substantially eliminates the need for guess work when placing thepressure sensor14 in the esophagus.
• The[0016]catheter12 typically comprises a 5 french, pliable and softtubular body20 which maximizes patient comfort and minimizes effects on normal breathing. Thecatheter12 has a length which, in one exemplary embodiment, may be about 87 cm when sized for an adult. A conventional femaleLuer hub connector22 or other suitable connector may be provided at aproximal end24 of thecatheter12 for permitting a pressure transducer to be easily connected to thecatheter12 as explained further on. As shown in FIG. 2, thecatheter12 defines an inflation lumen26 that typically extends within thecatheter12 such that it communicates with the interior of thepressure sensor14 via one or more openings28 located in a wall portion of thecatheter12 enclosed by thepressure sensor14.
• The[0017]catheter12 is preferably made from a radio-opaque material such as poly(vinyl chloride) or polyurethane. Thecatheter12 may be provided with a plurality ofdepth markings30, typically in the form of circumferential gradations. Themarkings30 are preferably of a type that can be easily seen, therefore, further aiding the user of thecatheter device10 to appropriately position thepressure sensor14 within the esophagus or other part of the body of the patient.
• The[0018]pressure sensor14 preferably comprises anelongated balloon15 element having a length which is typically about 10 cm and about 3-4 cc in air capacity, although the exact size of theballoon14 may be selected so that when positioned within the esophagus, it occupies the lower third of the thorax to properly represent intra-thoracic pressure oscillation independent of cardiac oscillation. Theballoon15 may be made from a soft, preferably latex free material such as poly(vinyl chloride) or polyurethane. Thedistal-most end32 of thepressure sensor14 is located about 5 cm from the distal end of thecatheter12 offering a thin lead ahead of the balloon to ease passage through the nasal passages, oral pharynx and esophagus.
• In operation, the[0019]pressure sensor14 of thecatheter device10 monitors esophageal pressure in the following manner. Theballoon15 is only partially filled with air (about 1 cc) as it rests inside the esophagus. During inhalation intra-thoracic pressure becomes sub-atmospheric (negative). The sub-atmospheric pressure is applied to the walls of the pressure sensor balloon attempting to more fully expand or fill the balloon. During exhalation intra-thoracic pressure becomes positive. The positive pressure is applied to the walls of the pressure sensor balloon attempting to collapse or empty the balloon. The conduit defined by the inflation lumen26 of thecatheter12 connects thepressure sensor balloon14 to a transducer attached to theport18. It is important that the pressure sensor balloon has the correct amount of residual air so slight changes in intra-thoracic pressures are transmitted to the transducer without the distortion of any elastic properties from the balloon wall stretching. The lumen26 channels air and pressure into theballoon15 through the one or more openings28 in the catheter wall that pass directly to the inside of theballoon15. The pressure in theballoon15 is transmitted to the proximal end of the lumen26 which communicates with apressure transducer50 via the stylettransducer coupler assembly16 as shown in FIG. 4 or via thehub connector22 as shown in FIG. 5. The pressure transducer converts the positive and negative esophageal pressure oscillations (mechanical energy) to electronic signals and units of pressure. The esophageal pressures of the person receiving thecatheter device10 will be reflected by air pressure changes within theballoon15.
• As shown in FIG. 3, the stylet[0020]transducer coupler assembly16 of thecatheter device10 comprises acoupler34 and astylet36. Thecoupler34 includes a substantially straightmain tube section38 having distal40 and proximal ends42, and the earlier mentionedtransducer port tube18. Thedistal end40 of themain tube section38 is tapered to permit thecoupler34 to be received within thehub connector22 of thecatheter12 in a friction fit manner. The proximal end42 of themain tube section38 is sealed by a cap-like closure44. Thestylet36 is a wire-like member, the proximal end of which may be permanently affixed to a cylindrical portion46 of theclosure44 extending into themain tube section38.
• The[0021]stylet36 of thetransducer coupler assembly16 is threaded through the inflation lumen26 of the catheter12 (FIG. 2) adding rigidity to thecatheter12, hence aiding the insertion thereof into the esophagus and the positioning of thepressure sensor14 therein. It is preferred that the distal end48 of thestylet36 be blunt (FIG. 2), with a rounded tip, and that the entire stylet be coated with PTFE to aid in removing it from the inflation lumen26 after the balloon is properly placed.
• The[0022]transducer port18 of thestylet coupler assembly16 is adapted to accept astandard pressure transducer50 to thecoupler assembly16 so that thetransducer50, in conjunction with thepressure sensor14, may be used in concert for correctly positioning the pressure sensor in the esophagus. Once the pressure sensor is correctly positioned in the esophagus, thepressure transducer50 is then removed from theport18 of thecoupler assembly16. The stylettransducer coupler assembly16 is withdrawn from thecatheter12. Thepressure transducer50 may then be attached to theconnector22 of thecatheter12 and operated in conjunction with thepressure sensor14 to monitor esophageal pressure.
• While the foregoing invention has been described with reference to the above embodiments, various modifications and changes can be made without departing from the spirit of the invention. Accordingly, all such modifications and changes are considered to be within the scope of the appended claims.[0023]

Claims (20)

What is claimed is:

1. An esophageal catheter device comprising:

a catheter including an open end and a closed end, the closed end for removably mounting one of a pressure transducer and removably receiving a stylet;

a balloon affixed to an exterior surface of the catheter, the balloon useable as a pressure sensor;

a balloon inflation lumen extending through the catheter in communication with the interior of the balloon through at least one aperture extending through the catheter; and

a stylet assembly including a stylet for providing appropriate rigidity to the catheter to aid insertion into the esophagus and a port for removably mounting a pressure transducer.

2. The esophageal catheter device according toclaim 1, wherein the stylet assembly further includes a coupler.

3. The esophageal catheter device according toclaim 2, wherein the coupler includes the port for mounting the pressure transducer.

4. The esophageal catheter device according toclaim 2, wherein the coupler includes a main tube section, the port for mounting the pressure transducer extending from the main tube section.

5. The esophageal catheter device according toclaim 1, wherein the catheter includes a plurality of depth markings.

6. The esophageal catheter device according toclaim 1, wherein the stylet assembly further includes a coupler and a closure sealing an end of the coupler, the stylet having an end affixed to a portion of the closure.

7. The esophageal catheter device according toclaim 6, wherein the coupler includes the port for mounting the pressure transducer.

8. The esophageal catheter device according toclaim 1, further comprising a hub connector disposed at the open end of the catheter.

9. The esophageal catheter device according toclaim 1, wherein the catheter is made from a radio-opaque material.

10. The esophageal catheter device according toclaim 1, wherein the balloon is made from a latex-free material.

11. A stylet assembly for an esophageal catheter device having a balloon affixed to an exterior surface of the catheter, the balloon useable as a pressure sensor; the stylet assembly comprising:

a coupler;

a stylet having an end affixed to the coupler; and

a port extending from the coupler for removably mounting a pressure transducer.

12. The stylet assembly according toclaim 11, wherein the coupler includes a main tube section, the port for mounting the pressure transducer extending from the main tube section.

13. The stylet assembly according toclaim 11, wherein the stylet assembly further includes a closure sealing an end of the coupler, the stylet having an end affixed to a portion of the closure.

14. A method for intra-thoracic pressure monitoring, the method comprising the steps of:

providing an esophageal catheter device including a catheter, a balloon affixed to an exterior surface of the catheter, the balloon useable as a pressure sensor, a balloon inflation lumen extending through the catheter in communication with the interior of the balloon through at least one aperture extending through the catheter, and a stylet assembly including a stylet for providing appropriate rigidity to the catheter to aid insertion in the esophagus and a port for removably mounting a pressure transducer;

mounting a pressure transducer to the port of the stylet assembly;

inserting the catheter device into an esophagus;

adding the correct amount of air to the sensor balloon;

positioning the sensor balloon of the catheter device in a desired location in the esophagus using pressure information obtained through the sensor balloon, the stylet assembly and pressure transducer working in concert.

15. The method according toclaim 14, further comprising the steps of:

removing the pressure transducer from the port;

removing the stylet assembly from the open end of the catheter;

mounting the pressure transducer to the open end of the catheter; and

monitoring esophageal pressure using pressure information obtained through the sensor balloon and the pressure transducer working in concert.

16. The method according toclaim 14, wherein the stylet assembly further includes a coupler.

17. The method according toclaim 16, wherein the coupler includes the port for mounting the pressure transducer.

18. The method according toclaim 16, wherein the coupler includes a main tube section, the port for mounting the pressure transducer extending from the main tube section.

19. The method according toclaim 14, wherein the catheter is made from a radio-opaque material.

20. The method according toclaim 14, wherein the balloon is made from a latex-free material.

Images