WO1988000809A1 - Intrauterine catheter apparatus and method of use - Google Patents

Abstract

An intrauterine catheter (10) adapted for transcervical insertion into the uterus during labor. At least two independent lumens (20, 22) are provided in the catheter (10) to allow monitoring intrauterine pressure while simultaneously conducting various therapeutic or diagnostic procedures. A first lumen (20) includes a pressure sensing means (46) at an intrauterine end (28) of the catheter. Signals from the pressure sensing means (46) are transmitted through the first lumen (20) to a device (60) which converts the signals into a visual display (66) of the amount of intrauterine pressure. An access port (44) extends through the intrauterine end (30) of a second lumen (22), thus allowing fluid communication between the uterus and the second lumen (22). The second lumen (22) is utilized for access to the uterus for therapeutic or diagnostic procedures such as saline amnioinfusion.

Description

INTRAUTERINE CATHETER APPARATUS AND METHOD OF USE

Background of the Invention This invention relates generally to the field of obstetrics, and in particular to an intrauterine catheter which is used during labor.

Previously, intrauterine catheters have been developed for measuring pressure within the uterus during labor, in order to monitor the frequency and intensity of uterine contractions. Typically, these catheters have been tubular and have a plurality of radially extending perforations through the catheter adjacent its intrauterine end, the end of the catheter which is inserted within the uterus. The catheter is filled with fluid, and the pressure within the uterus is transmitted to this fluid through the perforations. The other end of the catheter, the extracorporeal end, is attached to a transducer and recorder which generate a visual display of the intrauterine pressure. In addition to monitoring intrauterine pressure, it is also desirable to gain access to the uterine cavity during labor to perform certain therapeutic or diagnostic procedures. One such procedure which is particularly beneficial is "saline amnioinfusion," or the infusion of normal saline solution into the uterus. In the event that membranes rupture in the early stages of labor, allowing the loss of amniotic fluid, uterine contractions can cause compression of the umbilical cord and placenta. This decreases the flow of blood to the fetus and results in an irregular and harmful fetal heart rate pattern referred to as "repetitive variable decelerations". It has been found that saline amnioinfusion relieves pressure on the umbilical cord and ameliorates variable decelerations without maternal or neonatal complications. This technique has often improved the fetal heart rate condition so significantly that the patient has been able to continue labor until normal vaginal delivery of an infant. In contrast, had the pattern of variable decelerations continued without amnioinfusion, cesarean section would have been performed. Saline amnioinfusion has also been beneficial for the dilution of in utero meconium, a condition during which meconium, which is fetal fecal matter, is present in the uterus.

Previously, saline amnioinfusion has been conducted with the above described pressure monitoring catheter. However, the extracorporeal end of the catheter must first be disconnected from the transducer and attached to a source of saline solution. The saline flows into the uterus through the radial perforations at the intrauterine end of the catheter. After amnioinfusion is completed, the catheter must be reconnected to the transducer, flushed with saline, and the visual pressure display must be recalibrated. Even if the extracorporeal end of the catheter were to branch off into a "Y" shape, so that the catheter could be secured to both the pressure transducer and the source of saline, a falsely elevated baseline pressure is seen which may not accurately reflect the real intrauterine pressure.

The major disadvantage of these arrangements is that while amnioinfusion is taking place, pressure monitoring must be interrupted, thus depriving the medical staff of critical information about uterine contractions. Because of the lack of information, or the lack of accurate information, catastrophic uterine rupture may occur. Further, rearranging the catheter and auxiliary equipment each time amnioinfusion is required is a time consuming and confusing process which may be incorrectly carried out, particularly if the medical staff is inexperienced. Additionally, the manipulation of the extracorporeal end of the catheter while the catheter is inserted within the saline amnioinfusion is only in use at a number of well equipped hospitals in large urban areas.

Thus, there is a need for an easily operated apparatus which allows access to the uterus for diagnostic and therapeutic procedures, while permitting simultaneous monitoring of intrauterine pressure.

Summary of the Invention

The present invention comprises a catheter which is elongated, flexible, and of small enough outside diameter to be inserted transcervically during labor. The catheter includes at least two lumens, each with an intrauterine end and an extracorporeal end. Means are provided on the first lumen intrauterine end for sensing pressure within the uterus. Also, means are provided on the second lumen intrauterine end for permitting access to the uterus for therapeutic and diagnostic procedures, such as saline amnioinfusion.

A key feature of the present invention is that while access to the uterus is being provided through the second lumen, intrauterine pressure can be simultaneously monitored through the first lumen. As a result, intrauterine pressure monitoring does not need to be interrupted in order to use the catheter for procedures such as saline amnioinfusion, and false elevation of baseline pressure does not occur.

In one preferred embodiment of the invention, the pressure sensing means comprises at least one pressure port extending through the first lumen. When the first lumen is filled with fluid, changes in pressure within the uterus are transmitted through the fluid within the first lumen. The extracorporeal end of the first lumen is attached to a transducer which converts changes in fluid pressure within the first lumen to an electrical signal which, in turn, is fed to a recorder to provide a visual display and a record of the amount of intrauterine pressure. The intrauterine end of the second lumen includes an access port so that the second lumen is in fluid communication with the uterus. Thus, second lumen can be utilized for procedures requiring the infusion of fluids into or the withdrawal of fluids from the uterus. To conduct saline amnioinfusion, the intrauterine end of the catheter is simply secured to a source of saline solution.

Advantageously, the present catheter is simple to operate in that the first lumen does not have to be disconnected and reattached to the transducer each time access to the uterus through the second lumen is required. Furthermore, the false elevation of baseline pressure that occurs during amnioinfusion is eliminated. Once the catheter is set up in combination with the proper auxiliary equipment, there is minimal intervention required for operation of the catheter, thus saving time and avoiding the risk of mistakes by the medical staff while setting up the catheter and its auxiliary equipment. As a result of its ease in operation, the present invention will make available the use of procedures such as saline amnioinfusion in smaller hospitals where diagnostic and therapeutic intervention are not presently available.

The present catheter may be packaged in a kit with other sterile disposable auxiliary components. Such a kit would include the catheter; a syringe for filling the first lumen with fluid; a stopcock for attaching the first lumen and the syringe to the transducer; and a rigid introducer tube through which the catheter is inserted into the uterus. Some or all of these components can be eliminated if an electronic pressure transducer is used in one lumen.

Another aspect of the invention is the arrangement of auxiliary components used in combination with the catheter for simultaneous pressure monitoring and saline amnioinfusion. Preferably, the extracorporeal end of the first lumen is attached to a signal processing means which receives signals from the pressure sensing means within the first lumen, and converts these signals to a visual display of the intrauterine pressure. Also, a source of saline solution is provided for introduction to the second lumen, as well as a means for controlling the rate of flow of saline through the second lumen. The arrangement may also include a warmer for raising the temperature of the saline solution to approximately body temperature. Brief Description of the Drawings

Figure 1 is a perspective view of an intrauterine catheter according to one preferred embodiment of the present invention.

Figure 2a is a cross sectional view of the catheter in Figure 1, taken along line 2-2, showing one preferred embodiment of the catheter construction.

Figure 2b is a cross sectional view of the catheter in Figure 1, taken along line 2-2, showing another preferred embodiment of the catheter construction. Figure 3 is an enlarged perspective view of the intrauterine end of the catheter shown in Figures 1 and 2a.

Figure 4 is an enlarged perspective view of the intrauterine end of the catheter shown in Figures 1 and 2b.

Figure 5 is a schematic representation of the present catheter and auxiliary equipment used during simultaneous saline amnioinfusion and pressure monitoring, according to one preferred embodiment of the invention. Figure 6 is a schematic representation of the present catheter and auxiliary equipment used during simultaneous saline amnioinfusion and pressure monitoring, according to another preferred embodiment of the invention.

Figure 7 is an enlarged partial perspective view of the intrauterine end of a catheter and auxiliary equipment according to yet another preferred embodiment of the invention.

Detailed Description of the Preferred Embodiments Referring to Figure 1, a preferred embodiment of the present catheter 10 is shown. The catheter 10 has an intrauterine end 12 and an extracorporeal end 14. The catheter 10 is elongated and flexible, and ma y be formed from any one of a number of biocompfatible polymers, such as polyurethane.

The catheter 10 includes a body portion 16, one end of which forms the intrauterine end 12 of the catheter 10. The other end of the body portion 16 is joined to a tubular coupler 18. Referring to Figures 2a and 3, it can be seen that the interior of the body portion 16 is divided into two independent lumens, a pressure lumen 20 and an access lumen 22. The lumens 20,22 are substantially parallel to each other, and extend through the entire body portion 16. The exterior of the body portion 16 is substantially circular in cross section, and is formed by an outer wall 24. Extending the across the interior of the outer wall 24 is a curved, arcuate inner wall 26. Both ends of the inner wall 26 are joined to the outer wall 24, so that the boundaries of each lumen 20,22 are defined by a side of the inner wall 26, and an arcuate portion of the outer wall 24. As a result, the pressure lumen 20 is crescent shaped in cross section, whereas the access lumen 22 is oblong.

Each lumen 20, 22 has an intrauterine end 28, 30, respectively, and an extracorporeal end 32, 34, respectively. The intrauterine ends 28, 30, of the lumens 20, 22 are coincident with the intrauterine end 12 of the catheter 10. Likewise, the extracorporeal ends 32, 34 of the lumens 20, 22 are coincident with the extracorporeal end 14 of the catheter 10. As seen in Figure 1, the extracorporeal ends 32, 34 of the lumens 20, 22 form tubular branches 36, 38 which are independent of each other. The independent branches 36, 38 of the lumens 20, 22 are joined together by the coupler 18 and feed into the body portion 16. The extracorporeal end 32, 34 of each lumen 20, 22 terminates in an adapter 40 which allows fluid flow into and out of the lumens 20, 22. Preferably, the adapters 40 are male luer locks. A clip 42 surrounds the branch 38 of the access lumen 22, and is shown in an open position. When in a closed position (not shown), the clamp 40 pinches the access lumen 22 to prevent fluid flow therethrough.

The intrauterine end 12 of the catheter 10 is shown in detail in Figure 3. The intrauterine end 30 of the access lumen 22 terminates in an access port 44, which extends axially into the access lumen 22. Likewise, the intrauterine end 28 of the pressure lumen 20 terminates in a pressure port 46, which extends axially into the pressure lumen 20. The access lumen 22 is slightly longer than the pressure lumen 20, and thus the intrauterine end

30 of the access lumen 22 extends past the intrauterine end 28 of the pressure lumen 20. Preferably, the resulting space between the access port 44 and the pressure port 46 is on the order of 1 to 5 centimeters. This avoids the intermingling of any fluid flow through the access port 44 and through the pressure port 46.

Figures 2b and 4 show an alternate embodiment of the body portion 16. Similar numbers, with the subscript "a" will be used to describe similar elements of the body portion 16. In this embodiment, both the access lumen 22a, and the pressure lumen 20a are circular in cross section. The lumens 20a, 22a are joined along their respective exterior surfaces so as to form a "double barrel" or "figure 8" type shape when viewed in cross section. As seen in Figure 4, the access lumen 22a and the pressure lumen 20a are coterminal. The intrauterine end 28a of the pressure lumen 20a terminates at a cap 48. Adjacent the intrauterine end 28a of the pressure lumen 20a, a plurality of perforate pressure ports 46a extend radially into the pressure lumen 20a. The access lumen 22a terminates in an axially extending access port 44a.

Turning now to Figure 5, the catheter 10 is shown in operation. The outside diameter of the body portion 16 is sufficiently small for the intrauterine end 12 of the catheter 10 to be inserted transcervically into a uterus 50. Preferably, the body portion 16 has a substantially uniform outside diameter of less than about 2 centimeters. An elongated inserter tube 52 is provided to aid the insertion of the catheter 10. The tube 52 is substantially rigid relatively to the catheter 10, and has an inside diameter which permits the body portion 16 of the catheter 10 to be slid through the tube 52. The tube 52 is partially inserted into the uterus 50 and guides the catheter 10 as it is slid past a fetus 54. The catheter 10 is slid into the tube 52 far enough for the intrauterine end 12 of the catheter 10 to extend out of the tube 52. The length of the body portion 16, from the coupler 18 to the intrauterine end 12 of the catheter, preferably is at least 45 centimeters in order for the catheter 10 to extend sufficiently far into the uterus 50 beyond the inserter tube 52. Once inserted within the uterus 50, no balloons are required to anchor the catheter 10.

Auxiliary pressure sensing equipment 56 is provided so that intrauterine pressure can be monitored through the pressure lumen 20. Prior to insertion of the catheter 10 within in the uterus 50, the pressure lumen 20 is filled with saline solution. This is accomplished with a syringe 58, which mates with the adapter 40 on the pressure lumen extracorporeal end 32. After filling the pressure lumen 20 and inserting the catheter 10, the fluid within in the pressure lumen 20 communicates with the amniotic fluid within the uterus 50 through the pressure port 46. Thus, changes in the uterine pressure are transmitted through the fluid within the pressure lumen 20. To convert these signals into a visual display, the extracorporeal end 32 of the pressure lumen 20 is attached to a stem 60 on a physiological pressure transducer 62, such as that sold by Transamerica Delaval of Pasadena, California. Fluid pressure signals from the pressure port 46 are processed by the transducer 60 into electrical signals which pass through a conductor 64 to a recorder 66. The recorder 66 provides a visual display and record of the amount of intrauterine pressure.

To properly "zero" or calibrate the recorder 66, the syringe 58 and a three-way stop cock 68 are also attached to another stem 70 on the transducer 60. The stop cock 68 has three fittings; a lower fitting 72, which is secured to the transducer stem 70; a central fitting 74, which is secured to the syringe 58; and an upper fitting 76, which is open to the atmosphere. A lever 80, shown in broken lines, is rotatable to three different positions which allow flow through any two of the fittings 72, 74 and 76. To zero the recorder 66, the lever 80 is initially adjusted so that flow is permitted through the central and lower fittings 74, 72 to fill the transducer 60 with saline from the syringe 60. The lever 80 is then rotated to allow flow through the lower and upper fittings 72, 76, which vents the transducer 60 to the atmosphere through the upper fitting 76. At this point, the recorder 66 is calibrated to read zero pressure. The lever 80 is then rotated to close all flow through the upper fitting 76. Preferably, the syringe 58, the stop cock fittings 72, 74, 76 and the transducer stems 62, 70 all have luer lock type adapters to facilitate the attachment of each of the components. The inserter tube 52, the stop cock 68, syringe 58, and catheter 10 preferably are all sold together as a sterile kit which is used for a single patient and then disposed. While pressure monitoring is taking place through the pressure lumen 20, the access lumen 22 is free to provide access to the uterus 50 for any of a number of therapeutic or diagnostic procedures. These procedures can be carried out without requiring the interruption of pressure monitoring through the pressure lumen 20.

Figure 5 schematically shows a layout for auxiliary infusion equipment 82 used for performing saline amnioinfusion through the access lumen 22. The equipment 82 comprises a source of normal saline solution such as a flexible, plastic saline bag 84. Saline from the saline bag 84 flows into a variable speed pump 86 of the type sold by IVAC or IMAD. The pump 86 is adjustable to selectively vary the flow rate of saline being pumped into the uterus 50 to one of at least two known flow rates. The saline passes from the pump 80 to a warmer 88, which raises the temperature of the saline to approximately body temperature. The extracorporeal end 34 of the access lumen 22 is attached to the warmer 88. Saline passing through the access lumen 22 is introduced to the uterus through the access port 44.

As will be apparent to those skilled in the art, various types of devices can be used for the warmer 88, for example a heat exchanger normally used as a blood warmer. Although not shown, the branch 36 of the access lumen 22 may pass directly through the warmer 86, or alternatively the warmer 88 may be positioned between the saline bag 84 and the pump 46.

Preferably, saline amnioinfusion is conducted in two stages. During each stage, a certain volume of saline is infused at a certain flow rate. By adjusting the pump 86 so that the flow rate is known, the volume of saline infused can be determined by timing the period during which the pump 86 is turned on. After the desired amount of infusion has taken place, the pump 86 is turned off and the clamp 42 is closed to prevent additional flow through the access lumen 22. Thus, once the access lumen 22 is attached to the auxiliary infusion equipment 82, there is no need to rearrange the equipment 82 or detach the access lumen 22.

Figure 6 shows an alternate arrangement for the auxiliary equipment 82 used during saline amnioinfusion.

Although not shown, the pressure lumen 20 may be attached to the same auxiliary pressure sensing equipment 56 as used in Figure 5 and described above. Saline is provided from a saline bag 84, however, rather than using the pump 86, a constant pressure source 90 is provided to cause the saline to flow into the uterus 50. For example, the pressure source 90 may comprise a weight (not shown) which is placed on the saline bag 84, causing it to collapse.

Alternatively, the saline bag 84 may be raised above the intrauterine end 30 of the access lumen 22 so that gravity is the source of pressure 90.

The saline flows from the saline bag 84 and through a flow regulator 92 which is adjustable to limit the saline flow to at least two different known flow rates. Flow is controlled by a restrictive flow type valve, such as that sold as the "DIAL-A-FLO" DAF-30, manufactured by Sorenson Research Co., Salt Lake City, Utah. Although not shown, the valve may be located along the lumen 22. A warmer 88 is downstream of the flow regulator 92, and raises the temperature of the saline. Saline is introduced to the access lumen 22 through the adaptor 40, which is attached to the warmer 88.

It is to be understood that in addition to saline amnioinfusion, the access lumen 22 can be utilized for other procedures such as infusion of antibiotics, the withdrawal of amniotic fluid for culture and gram stain analysis, the withdrawal of amniotic fluid to detect in utero meconium, providing visualization of the uterus through an optical device, etc.

Figure 7 shows the intrauterine end 12 of an alternate embodiment of the catheter 10. The subscript "b" is used to denote like elements. The access lumen 22b is substantially circular when viewed in cross-section. The pressure lumen 20b also has a circular cross-section, but of a smaller diameter than the access lumen 22b. The pressure lumen 20b is positioned within the access lumen 22b and extends through the access lumen 22b. The exterior of the pressure lumen 20b is secured to the interior of the access lumen 22b.

A pressure sensing device 100 is shown at the intrauterine end 28b of the pressure lumen 20b. A cable 102 extends from the pressure sensing device 100 through the pressure lumen 20b, and transmits signals from the pressure sensing device 100 through the pressure lumen 20b and to a recorder 104. The pressure sensor 100 may, for example, comprise a electronic transducer which, when exposed to fluid within the uterus 50, generates an electrical signal which is transmitted through the cable 102 and converted by the recorder 104 into a visual display. Alternatively, the pressure sensor 100 may comprise an optical transducer and the cable 102 may be a fiber optic cable which transmits signals from the pressure sensor 100 to the recorder 104, which would include means for processing the optical signals from the pressure sensor 100 and converting them to a visual display. Such an optical pressure sensing system is sold as the "Camino System 420" by Camino Labs, of San Diego, California. Although the present invention has been described with reference to preferred embodiments, numerous modifications and rearrangements can be made, and still the result will come within the scope of the invention. For example, the catheter may be provided with more than two lumens.

Claims

1. An intrauterine catheter (10) characterized by: a body portion (16) which is elongated, flexible, and of a small enough outside diameter to be inserted transcervically during labor subsequent to the rupture of the amniotic membrane, said body portion (16) being sufficiently long to remain inserted within the uterus without an inflatable anchoring device; a first lumen (20) within said body portion (16) for monitoring pressure within the uterus, said first lumen (20) having an intrauterine end (28) and an extracorporeal end (32); means (46) on said first lumen intrauterine end (28) for sensing pressure; means (40) on said first lumen extracorporeal end

(32) for attaching said first lumen (20) to a device (60) for processing signals from said pressure sensing means (46); a second lumen (22) independent of said first lumen (20), for providing access to the uterus for saline amnioinfusion or other diagnostic or therapeutic procedures while permitting simultaneous, uninterrupted pressure monitoring through said first lumen (20), said second lumen (22) extending substantially parallel to said first lumen (20) throughout said body portion (16) and having an extracorporeal end (34) and an intrauterine end (30), said second lumen intrauterine end (30) including an access port (44) proximate said pressure sensing means (46), said access port (44) establishing direct fluid communication between said second lumen (22) and the uterus, thus permitting fluid infusion to the uterus and withdrawal of fluid from the uterus through said second lumen (22); and means (40) on said second lumen extracorporeal end (34) for attaching. said second lumen (22) to a source of fluid (84) for infusion into the uterus, said first lumen extracorporeal end (32) and said second lumen extracorporeal (34) end branching off individually from said body portion (16), permitting simultaneous pressure monitoring and access to the uterus without disconnecting or reattaching the extracorporeal ends (32, 34) of said first and second lumens (20, 22) once attached to said signal processing device (60) and said fluid source (84), respectively.

2. A catheter as defined by Claim 1 further characterized in that said pressure sensing means comprises one or more pressure ports (46, 46a) in said first lumen which permit fluid communication between the uterus and said first lumen (20).

3. A catheter as defined by Claim 2, characterized in that said pressure port comprises a plurality of perforations (46a) extending radially (46a) through said first lumen (20), said perforations adjacent (46a) said first lumen intrauterine end (28a).

4. A catheter as defined by Claim 2, characterized in that said first lumen intrauterine end (28) terminates at said pressure port (46), said pressure port (46) extending axially into said first lumen (20).

5. A catheter as defined by Claim 4, characterized in that said second lumen intrauterine end (30) extends past said pressure port (46) on said first lumen (20).

6. A catheter as defined by Claim 1, characterized in that said pressure sensing means comprises a transducer (100) positioned at said first lumen intrauterine end (28) so as to be exposed to fluid within the uterus, and a conductive element (102) extending from said transducer (100) through said first lumen.

7. A catheter as defined by Claim 1, characterized in that said pressure sensing means comprises an optical pressure sensing device (100) positioned at said first lumen intrauterine end (28) so as to be exposed to fluid within the uterus, and at least one fiber optic cable (102) extending from said optical device (100) through said first lumen (20).

8. A catheter as defined by Claim 1, characterized in that said catheter includes an outer wall (24) having a substantially circular cross section, and an arcuate inner wall (26) extending across the interior of said outer wall (24), said inner wall (26) dividing the interior of said catheter into said first lumen (20) and said second lumen (22), so that said when viewed in cross section, said first lumen (20) is substantially crescent shaped and said second lumen is substantially oblong (22).

9. A catheter as defined by Claim 1, characterized in that said body portion (16) has a substantially uniform outside diameter.

10. A catheter as defined by Claim 1, characterized in that said first lumen (20) and said second lumen (22) are both substantially circular in cross section, said lumens (20, 22) being joined side by side along respective exterior surfaces.

11. A catheter as defined by Claim 1, characterized in that said first lumen (20c) and said second lumen (22c) are both substantially circular in cross section, said first lumen (20c) having a smaller diameter than said second lumen (22c), said first lumen (20c) extending through said second lumen (22c), the exterior of said first lumen (20c) being secured to the interior of said second lumen (22c).

12. A catheter as defined by Claim 1, characterized in that the outside diameter of said catheter (10) is less than approximately two centimeters.

13. A catheter as defined by Claim 1, characterized in that said attachment means comprises luer locks (40).

14. A catheter as defined by Claim 1, characterized in that said first lumen intrauterine end (28a) is coterminal with said second lumen intrauterine end (30).

15. An intrauterine catheter (10) which is elongated, flexible, and of a small enough outside diameter to be inserted transcervically during labor, subsequent to the rupture of the amniotic membrane, said catheter characterized by: a first lumen (20) for monitoring pressure within the uterus, said first lumen (20) having intrauterine end (28) and an extracorporeal end (32); means (46) on said first lumen intrauterine end

(28) for sensing pressure; a second lumen (22) independent of said first lumen (20) and having an extracorporeal end (34) and an intrauterine end (30); means (44) on said second lumen (22) for permitting access to the uterus for therapeutic or diagnostic procedures through said second lumen (22), while permitting simultaneous pressure monitoring through said first lumen (20).

16. A catheter as defined by Claim 15, characterized in that said pressure sensing means comprises one or more pressure ports (46) proximate said first lumen intrauterine end (28), said pressure ports (46) permitting fluid communication between the uterus and said first lumen (20).

17. A catheter as defined by Claim 15, characterized in that said access means comprises an access port (44) proximate said second lumen intrauterine end (30), said access port (44) permitting fluid communication between said second lumen (22) and the uterus.

18. A kit characterized: a) an elongated, flexible intrauterine catheter (10), said catheter (10) comprised of: a first lumen (20) for monitoring intrauterine pressure, said first lumen (20) having an intrauterine end (28) and an extracorporeal end (32), at least one pressure port (46) provided proximate said intrauterine end (28) to permit fluid communication between said uterus and said first lumen (20), an adapter (40) on said extracorporeal end (32) for attaching said first lumen (20) to a pressure transducer (60); and a second lumen (22) independent of said first lumen for providing direct access to the uterus for diagnostic or therapeutic procedures, including saline amnioinfusion, while intrauterine pressure is simultaneously being monitored through said first lumen (20), said second lumen (22) extending substantially parallel to said first lumen (20), said second lumen (22) having an intrauterine end (30) and an extracorporeal end (34), said second lumen intrauterine end (30) terminating in an access port (44) proximate said pressure port (46) on said first lumen (20) so that fluid communication is established between said second lumen (22) and the uterus, an adapter (40) on said second lumen (22) for attaching said second lumen extracorporeal end (34) to a source of fluid for amnioinfusion; b) a syringe (58) for injecting fluid into said first lumen (20); c) a three-way stop cock (68) comprising: a first fitting (72) which is adapted to be secured to said transducer (60); a second fitting (74) which is adapted to be secured to said syringe (58); a third fitting (76) to allow venting to the atmosphere; a lever (80) which is rotatable to permit flow through any two of said fittings; and d) a substantially rigid introducer tube (52) which is partially inserted into the uterus, said catheter (10) being inserted within the uterus by sliding through said introducer tube (52).

19. A kit as defined by Claim 18, characterized in that said catheter (10) is formed from an outer wall (24) having a substantially circular cross section, and an arcuate inner wall (26) extending across the interior of said outer wall (24), said inner wall (26) dividing the interior of said catheter (10) into said first lumen (20) and said second lumen (22), so that when viewed in cross section, said first lumen (20) is substantially crescent shaped, and said second lumen (22) is substantially oblong.

20. A kit as defined by Claim 19, characterized in that said first lumen intrauterine end (28) terminates in said pressure port (46), said pressure port (46) extending axially through said first lumen (22), said second lumen intrauterine end (30) terminating in said access port (44), said access port (44) extending axially through said second lumen (22).

21. A kit as defined by Claim 18, characterized in that said first lumen (20a) and said second lumen (22a) are both substantially circular in cross section, said lumens (20a, 22a) being joined side by side along respective exterior surfaces.

22. A kit as defined by Claim 21, characterized in that said pressure port and said first lumen (20) is comprised of a plurality of perforations (46a) extending radially through said first lumen (20), and said second lumen intrauterine end (30) terminating at said access opening (44), said access port (44) extending axially through said second lumen (22).

23. An apparatus for simultaneously monitoring intrauterine pressure and infusing saline solution into the uterus during labor, said apparatus characterized by: an elongated, flexible catheter (10) having a small enough outside diameter to be inserted transcervically during labor subsequent to the rupture of the amniotic membrane, said catheter (10) comprising: a first lumen (20) for monitoring pressure within the uterus, said first lumen (20) having an intrauterine end (28) and an extracorporeal end (30); means (46) on said first lumen intrauterine end (28) for sensing pressure; a second lumen (22) for providing access to the uterus for saline amnioinfusion while pressure monitoring is simultaneously taking place through said first lumen (20), said second lumen (22) extending substantially parallel to said first lumen (20) and having an extracorporeal end (34) and an intrauterine end (30), said second lumen intrauterine end (30) including an access port (44) proximate said pressure sensing means (46), said access port (44) permitting saline which is introduced through said second lumen extracorporeal end (34) to be infused into the uterus; means (60, 66) for processing signals from said pressure sensing means (46) and providing a visual display of the amount of intrauterine pressure, said first lumen extracorporeal end (32) being removably secured to said signal processing means (60, 66); a source of saline solution (84), said saline solution being introduced to said second lumen (22) through said second lumen extracorporeal end (34), said second lumen extracorporeal end (34) being removably secured to said saline source (84), said catheter (10) permitting simultaneous pressure monitoring and saline amnioinfusion without disconnecting and reattaching said extracorporeal ends (32, 34); and means (46, 92) for controlling the rate of flow of saline through said second lumen (22).

24. An apparatus as defined by Claim 23, further characterized by a warmer (88) which raises the temperature of the saline solution passing through said second lumen (22) to approximately body temperature.

25. An apparatus as defined by Claim 23, characterized in that said pressure sensing means comprises one or more pressure ports (46a) through said first lumen (20) which permit fluid communication between the uterus and said first lumen (20).

26. An apparatus as defined by Claim 23, characterized in that said flow controlling means comprises a pump (86), said pump (86) being adjustable to pump saline into said second lumen (22) at one of a plurality of predetermined flow rates.

27. An apparatus as defined by Claim 23, wherein said flow controlling means is characterized by: means (90) for providing pressure on the saline solution entering said second lumen (22); and a flow regulator (92) which is adjustable to limit the flow of saline solution through said second lumen (22) to one of a plurality of predetermined flow rates.

28. A method of monitoring intrauterine pressure and performing therapeutic and diagnostic procedures during labor, said method characterized by the steps of: providing a catheter (10) comprised of a first lumen (20) having intrauterine end (28) and an extracorporeal end (32), an independent second lumen (22) having an intrauterine end (30) and an extracorporeal end (34), a pressure sensing means (46) located proximate said first lumen intrauterine end (28), said second lumen intrauterine end (30) including an access port (44) which provides direct fluid communication between said uterus and said second lumen (22) means (40) on said first lumen extracorporeal end (32) for attaching said first lumen extracorporeal end (32) to a device (60) for processing signals from said pressure sensing means (46), and means (40) on said second lumen extracorporeal end (34) for attaching said second lumen (22) to a source of saline (84) for infusion into the uterus; joining said first lumen extracorporeal end (32) to a device (60, 66) which processes signals from said pressure sensing means (40) so as to provide a display of the intrauterine pressure; joining the second lumen extracorporeal end (34) to a source of saline solution (84); inserting said catheter (10) transcervically into the uterus, subsequent to the rupture of the amniotic membrane; monitoring intrauterine pressure through said first lumen (20) through said pressure sensing means (46); and simultaneously performing saline amnioinfusion or other therapeutic and diagnostic procedures through said second lumen (22) without requiring interruption of said pressure monitoring or rearranging the connections with said first and second lumen extracorporeal ends (32,

34).

29. A method as defined by Claim 28, wherein said pressure sensing means comprises a pressure port (46) through said first lumen (20), said method further characterized by the steps of; filling said first lumen (20) with fluid; transmitting changes in pressure within the uterus through said fluid in said first lumen (20) to a transducer (60) attached to said first lumen extracorporeal end (32); and converting electrical signals generated by the transducer (60) into a visual display of the value of the intrauterine pressure.

30. A method as defined by Claim 28, characterized in that said first lumen (20) is utilized for saline amnioinfusion.

31. A method as defined by Claim 30, further characterized by the steps of: controlling the rate of flow of saline solution into the uterus through said second lumen (22); and warming the saline solution within said second lumen (22) to approximately body temperature.