JP2003507111A - Improvements in catheter positioning - Google Patents

Abstract

SUMMARY A catheter is disclosed that includes means for measuring local pressure at two or more points along a catheter body. The points are preferably located at two different pressure zones, and more preferably at locations across valves such as blood vessels and organs. The present invention is directed to a catheter having means for monitoring local pressure at two or more points along a catheter body, or for measuring pressure at a single point along a catheter body. A method is provided for estimating the location of a catheter within a blood vessel, organ, or the like, with a catheter having means and movable to detect a pressure differential measurement. The present invention can be used by heat transfer devices to obtain more accurate knowledge of the location of blood vessels.

Description

Detailed Description of the Invention

The present invention relates to improvements in catheter positioning for monitoring cardiac output data.

US Pat. No. 5,509,424 discloses a catheter having a heat transfer device near its distal end, for use in monitoring intracardiac cardiac output. The device was chosen to be derived from a temperature difference signal based on the average raw blood temperature measurement detected by the proximal temperature sensor and the heating coil temperature measurement detected by the distal temperature sensor. The characteristics are used to determine the cardiac output.

An important consideration when using such catheters is the importance of the placement of the catheter and its heat transfer device. The human main pulmonary artery is typically only about 5 centimeters in length, so accurate positioning of the catheter is important for accurate cardiac output (CO) information.

An unpublished study of 60 patients found that the main pulmonary artery (PA)
After the normal floating of the catheter in, the tip of the catheter will be located 0 to 8 cm into the left or right main branch of the PA. Cardiac output (C
In the case of a catheter which determines O), this positioning is acceptable. However, in the case of a catheter that measures cardiac output based on the heat transfer principle, as disclosed in US Pat. No. 5,509,424, the position where the heat transfer element (HTD) is arranged is very important. . If the HTD is in the position of entering the branch, H
The TD will be sensitive to the part of the stream that gives lower CO. Also, if HTD
HTD will provide higher CO when is near high turbulence, for example near valves or bifurcations. Therefore, it is important to manage the placement location of the HTD to improve the overall accuracy of the CO determination.

One design of the catheter according to US Pat. No. 5,509,424 has a heat transfer device located 7.5 cm from its distal tip (FIG. 1). this is,
Judging from the clinical studies described above, 95% of those cases would ensure that the HTD is not in the branch. However, judging from a clinical study of 20 patients, it was found that about 20 to 30% of the time was affected by the placement position (CO determined by the heat transfer method was Was significantly lower than the CO determined by the method).

One object of the present invention is to provide an apparatus and method for a catheter for obtaining placement position information.

According to one aspect of the invention, there is provided a catheter including means for measuring localized pressure at two or more points along the catheter body.

The points are preferably located in two different pressure zones. The catheter preferably has a heat transfer device therein, and more preferably has a heat transfer device at or near its distal end. .

The pressure measuring means may be a lumen-filling fluid capable of transmitting a pressure waveform to a pressure transducer, which may be located external to the patient. Alternatively, pressure transducing means may be located at these points, the signal of which may be transmitted via electrical cables, fluids, or optical fibers. The converting means itself may be an optical means, a semiconductor, or some other means. In addition, the pressure measuring means,
It may be the same or different. The above transmission is
It could only travel along one lumen.

The measuring means is preferably two or more pressure measuring devices such as diaphragms arranged along the length of the catheter body. With reference to the information obtained from these different pressure measuring means, it can be calculated to indicate the position of the catheter in the blood vessel or organ, more specifically the position of the tip of the catheter and some heat transfer device. The catheter could use an existing lumen,
Alternatively, it may include an additional lumen for relaying information from the pressure measuring means to its proximal end.

According to a second aspect of the invention, assessing the placement of a catheter in a blood vessel, organ, etc., having means for monitoring local pressure at two or more points along the catheter body. A method is provided in which a catheter is placed along two different pressure regions, and pressure differential measurements between points in those two different regions are indicative of the placement position of the catheter.

The pressure sensing means of the present invention could be placed across a valve, such as a blood vessel or organ, such as a heart valve. In one embodiment of the invention, one pressure sensing means is located in the pulmonary artery and one pressure sensing means is located in the adjacent ventricle. This known and different pressure of blood in the pulmonary artery and ventricle creates a pressure differential, and, in combination with the recognition of arterial pressure at the valve described above, that pressure differential information is provided by the catheter tip and heat transfer device. It can be used to ensure that it is located in the desired location, for example to be sure that its tip is in the atrium, ventricle, or pulmonary artery.

Typically, catheters according to the invention will have means for positioning their pressure points such that the heat transfer device is centered in the main pulmonary artery.

According to a third aspect of the invention, there is provided a method of assessing the placement of a catheter in a blood vessel, organ or the like having means for monitoring local pressure at a point along the catheter body. , Where the catheter is placed in a first location, such as a blood vessel or organ, and the local pressure is measured, and then the catheter is moved to a second location, such as the blood vessel or organ, where it is localized. Pressure is measured, and the pressure measurements at the first and second placement positions are indicative of the placement position of the catheter.

This method will use only one pressure measuring means to detect their pressure waveforms. This allows, for example, in the cardiovascular system of children and neonates,
It allows the size of the catheter to be minimized in applications requiring the smallest possible outer diameter. The catheter will be advanced anteriorly until a change (indicated by the pressure measuring means) in the indicating pressure waveform indicates that the sensor has crossed the valve. The catheter could then be withdrawn until it crosses the valve again to confirm placement. In this way, any part of the catheter at a certain known distance from the pressure sensing means can be placed at a known location with respect to the position of the valve.

In one preferred embodiment, the catheter could be provided with calibrated distance markers on its outer surface to facilitate accurate determination of insertion and retraction distances.

According to a fourth aspect of the invention, for measuring an internal fluid line whose fluid pressure is related to the overall pressure of the surrounding fluid outside the catheter, and its fluid pressure in said internal line. And at least one means of

The tubing could directly utilize a portion of the fluid surrounding the catheter. Alternatively, the tubing could relay information obtained from external pressure measuring means such as a diaphragm. Preferably, the catheter described above has a heat transfer device at or near its distal end.

BRIEF DESCRIPTION OF THE DRAWINGS By way of example only, the accompanying schematic drawings show embodiments of the invention in which: FIG. 1 shows a portion of a first catheter according to the invention. FIG.

[0020]   2 is a cross-sectional view through a portion of a second catheter according to the present invention.

FIG. 3 is an R.V. provided by the catheter shown in FIG. V. A trace and a PA trace are shown.

[0022]   FIG. 4 shows the arrangement position of the pulmonary artery catheter.

Referring to the drawings, first, FIG. 1 is a cross-sectional view of a first catheter 2 having an internal fluid pipe 4. Each end of the tubing 4 is covered with a septum 6 aligned with the outer wall 8 of the catheter. The pipe 4 is filled with a fluid 10 such as sterile saline or gel. This fluid should be non-toxic and biocompatible.

At the center of the tubing 4 is provided a third diaphragm 11 which is connected to a pressure sensor (not shown) at the end of the lumen 14.

In use, the pressure exerted on one end diaphragm 6 of the pipe 4 is the same as the other end diaphragm 6.
This section of catheter 2 is intended to be placed across a pressure differential boundary (dashed line AA), such as a ventricular valve, as opposed to the pressure exerted on it. Their end diaphragm 6
The different pressures on the membranes (through the internal fluid 10) result in a movement of the intermediate membrane 11, and this movement of the membrane 11 can be measured with a pressure sensor.

In combination with the knowledge of the blood pressure in and around the heart, waiting for the desired pressure measurement to confirm that the position of the tubing 4 has crossed the valve provides a clear indication of the correct placement of the catheter 2. You can get a good confirmation. The precise position of the tip of the catheter and any associated heat transfer device can then be ascertained and the precise determination of information related to that heat transfer device also possible.

FIG. 2 shows two measuring means 13, with respective waveform transmitting means 13a, 14a.
A second catheter body 12 having 14 is shown. The broken line BB shows the pulmonary valve. The pressure waveform trace measured at location 13 would be as shown in FIG. The waveform is the right ventricle R. V. Is an index of. Similarly,
Position 14 will show a waveform that is also indicative of the pulmonary artery PA, also shown in FIG. Positioning the catheter 12 so as to obtain these individual waveforms allows the user to know the position of the pressure measuring means 13, 14 and thereby allows them to be spaced a fixed distance along the catheter. The location of some other portion of a catheter 12 may also be known. For example, if distal tip 16 were 10 cm from point 14, the user would know that tip was about 10 cm from the pulmonary valve. For the heat transfer device 15 as well, it will be known that it is located 1 cm from the point 14, for example.

FIG. 4 shows the positioning of the pulmonary artery catheter. Catheter (2)
Extends through the superior vena cava (17) into the right atrium (18), then into the right ventricle (19) and further through the main pulmonary artery (20) into the right pulmonary branch (21). The use of pressure sensing means allows its heat transfer device to be located in the main pulmonary artery. The present invention provides two approaches to actual clinical practice.

Approach 1 Providing a separate lumen for pressure monitoring. Current catheters according to US Pat. No. 5,509,424 have a cross section with six lumens as described below.

The proximal injection lumen terminates in a port located 30 cm from the distal tip. When its distal tip is located in the pulmonary artery, the above-mentioned proximal infusion port is located in the right atrium or vena cava, which results in bolus cardiac output infusion and right arterial pressure. Monitoring, blood sampling, or
Allows injection of solution.

The pulmonary artery (PA) distal injection lumen terminates at the distal tip. During insertion, this port is used to monitor the position of the catheter via transient pressure measurements. When fully inserted, this port is located in the pulmonary artery (which allows for measurement of pulmonary arterial pressure and pressure at the pulmonary arterial capillary wedge, or mixed venous blood sampling). The port also allows for solution injection, pressure monitoring, or blood sampling.

The distal and proximal thermistor lumens are each about 7.
It contains conductive wires for those thermistors located on the catheter surface at a distance of 5 cm and 11 cm. The thermistors are used to measure temperature and, together with a thermal coil, produce the data used to calculate cardiac output. The distal thermistor is located just below the thermal coil described above.

The heat coil lumen includes a heat coil lead located at a distance of 7.5 cm from the distal tip. The thermal coil produces the heat necessary to maintain a constant temperature differential between the proximal and distal thermistors. The energy required to maintain that constant temperature differential is used to continuously calculate cardiac output.

The balloon inflation lumen has a one-way stopcock at its proximal end and terminates in a latex balloon located at the distal tip. Once the catheter is properly placed in the pulmonary artery, the balloon described above is immediately inflated to measure the pressure at the pulmonary wedge. The balloon is inflated with a volume limited syringe.

The coupling of two thermistors and coil wires within one lumen allows two lumens to be used for pressure monitoring.

In this first approach, a heat transfer device (H
There is a slot (PC1) 3 cm below the TD) and another slot (PC2) 2 cm above the HTD in the second emptying lumen. With the catheter floating in place, the trace of PC1 should have a PA waveform, and PC2 should have a right ventricle (RV) waveform if the HTD is placed in the middle PA. The ingenious manipulation of the catheter position to achieve these traces ensures that the HT is in the right place.
Ensure that D is always located.

Approach 2 Another approach would be to empty only one lumen so that only one slot on the lower or upper side of the HTD is used.

A. For example, if the pressure slot is located 3-4 cm below the HTD, the catheter is advanced until the pressure slot shows a PA trace, and then the catheter is tipped in small increments (eg, It can be retracted (in 1 cm increments). At this time, the HTD would be located in the main PA just behind the pulmonary valve.

B. Alternatively, the slot described above is located 2 cm above the HTD. When the catheter is in place, it is retracted until an RV trace is observed, then 4 cm into the PA. At this time, the HTD is located in the main PA above the pulmonary valve.

The present invention can be used to gain a more accurate knowledge of the position of a catheter within a blood vessel, organ or the like. If the catheter contains a heat transfer device, the position of the heat transfer device can be calculated more accurately, which allows more accurate determination of the nature of the heat measurement and associated heart information. be able to.

Specific applications of the invention include: ensuring that a component is located in the pulmonary artery; ensuring that a component is located in the right ventricle; distal tip of a product Ensure that the pulmonary valve does not go beyond a certain distance;

The last point relates to some pulmonary artery catheter. It is important for patient well-being that the tip of any pulmonary artery catheter cannot be placed too far past the pulmonary valve.

The novel apparatus and method of the present invention could also be used in non-medical fields where precise placement of elongate tubing or the like at remote locations is required. Such areas include aeronautics, some fluid flow analysis, food and beverage processing and monitoring, water and sewer management, chemical engineering, engine fueling, and the like. In fact, the present invention is also applicable to any device that needs to be placed across a one-way valve under some fluid flow conditions and / or any fluid flow condition exhibiting a pressure differential.

[Brief description of drawings]

[Figure 1]   FIG. 3 is a cross-sectional view through a portion of a first catheter according to the present invention.

[Fig. 2]   FIG. 6 is a cross-sectional view through a portion of a second catheter according to the present invention.

FIG. 3 is a diagram illustrating the R.D. provided by the catheter shown in FIG. V. A trace and a PA trace are shown.

[Figure 4]   The arranging position of the pulmonary artery catheter is shown.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, K E, LS, MW, MZ, SD, SL, SZ, TZ, UG , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, BZ, C A, CH, CN, CR, CU, CZ, DE, DK, DM , DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, K E, KG, KP, KR, KZ, LC, LK, LR, LS , LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, RO, R U, SD, SE, SG, SI, SK, SL, TJ, TM , TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Weed, Ted Bander             United Kingdom, Stephen M. 40.             6 F L, Flemington Court             5 (72) Inventor McNair, Robert             United Kingdom, Glasgow G 42.9             A-L, Mount Florida, Stra             Nmore Road 93, Flats 2/1 (72) Inventor Wilson, Stephen             Edinburgh E.H.             17/7 eBee, Gil Morton, Dora             Mu Crescent 63 (72) Inventor Andrews, Simon             England, Glasgow G. 33.1.             G.A., Rob Royston, Lauden             Hill Road 24 F term (reference) 2F055 AA05 BB14 CC60 DD20 EE40                       FF49 GG49 HH07 HH08                 4C017 AA08 AA11 AB10 AC07 FF30                 4C167 AA01 AA31 BB05 BB12 BB26                       BB62 BB63 CC07 CC08 CC29                       DD01 HH11

Claims (23)

[Claims] 1. A catheter having a catheter body, the body comprising:
A catheter including means for measuring local pressure at two or more points along the catheter body. 2. A catheter according to claim 1, wherein the measuring means comprises two or more pressure measuring devices arranged along the length of the catheter body. 3. The catheter according to claim 2, wherein the pressure measuring device is a diaphragm. 4. The catheter of claim 1, wherein the means comprises one or more fluid-filled lumens or tubing. 5. The lumen or tubing, or 1 across each lumen or tubing
The catheter of claim 4, having one or more mid-spacing membranes. 6. A catheter according to any of the preceding claims, including a pressure transducing means. 7. A signal transmission means capable of transmitting localized pressure information from one or more points along the catheter body to the proximal end of the catheter. The catheter according to claim 6. 8. The signal comprises one or more electrical cables, fluids,
The catheter according to claim 7, which is also transmitted via an optical fiber. 9. A catheter according to any preceding claim, wherein pressure measurement information is conveyed along the catheter through one or more lumens within the catheter body. 10. A catheter according to any of the preceding claims, comprising one or more heat transfer devices. 11. A method for evaluating the position of a catheter having a means for monitoring local pressure at two or more points along the catheter body in a blood vessel, an organ or the like. A method in which a catheter is placed along two different pressure areas, and the pressure differential between the points in those two different areas is an indicator of the position of the catheter. 12. The method of claim 11, wherein the pressure monitoring means is positioned across a valve such as a blood vessel or organ. 13. The method of claim 12, wherein the pressure monitoring means is located across the valve of the heart. 14. A method for evaluating the placement position of a catheter in a blood vessel, an organ or the like, which has means for monitoring local pressure at a point along the catheter body, the method comprising: The local pressure is measured by being placed in a first position in an organ or the like, and then the catheter is moved to a second position in the blood vessel, organ or the like to measure the local pressure,
Then, a method in which the pressure measurement values at the first and second positions serve as an index regarding the placement position of the catheter. 15. The method of claim 14 for pediatric or neonatal catheters. 16. The method according to claim 14 or 15, wherein the catheter is located in a first position on one side of the valve and a second position on the other side of the valve. Method. 17. The method according to claim 14, wherein the catheter has calibrated distance markers on its outer surface. 18. An internal fluid tubing, the fluid pressure of which is related to the overall pressure of ambient fluid outside the catheter, and at least one means for measuring the fluid pressure within the internal tubing. catheter. 19. The catheter of claim 18, wherein the tubing uses a portion of the fluid surrounding the catheter. 20. The catheter of claim 18, wherein the tubing relays information obtained from the external pressure measuring means. 21. The catheter according to claim 20, wherein the external pressure measuring means is a diaphragm. 22. The catheter of any of claims 18-21, including a heat transfer device at or near its distal end. 23. Use according to any one of the following: aeronautics, fluid flow analysis, food and beverage processing and monitoring, water and sewer management, chemical engineering, fueling engines. And a catheter according to any one of claims 18 to 22.