A SYSTEM AND A METHOD FOR MEASURING VOLUMETRIC FLOW IN ARTERIES

Abstract

An arterial flow measurement system comprising: a catheter tube being which may be configured to be inserted into an artery, the catheter tube having longitudinal axis, a proximal end and a distal end, a first inner lumen providing fluid communication along the longitudinal axis of the catheter tube, a first opening (input opening) configured to provide fluid communication from the outside of the catheter tube and into the first inner lumen through a side wall of the catheter tube, a fluid guide element having an insertion state where the fluid guide element has a first cross-sectional diameter, and in a measuring state where the fluid guide element has a second-cross-sectional diameter, where the fluid guide element is configured to guide at least part of an arterial flow surrounding the fluid guide element into the first opening, a conversion element, where the conversion element is connected to the fluid guide element allowing a user to selectively transform the fluid guide element from an insertion state to a measuring state, and vice versa; and where the arterial flow measurement system comprises a flowmeter configured to measure the flow of a fluid wherein the flowmeter is in fluid communication with the first inner lumen of the catheter tube

Claims

1. An arterial flow measurement system comprising: a catheter tube being adapted to be inserted into an artery, the catheter tube having longitudinal axis, a proximal end and a distal end, a first inner lumen providing fluid communication along the longitudinal axis of the catheter tube, a first opening configured to provide fluid communication from the outside of the catheter tube and into the first inner lumen through a side wall of the catheter tube, a fluid guide element configured to guide at least part of an arterial flow surrounding the fluid guide element into the first opening, a flowmeter configured to measure the flow of a fluid, wherein the flowmeter is an outside-the-body flowmeter, and where the flowmeter is in fluid communication with the first inner lumen of the catheter tube; and the catheter tube comprising a third inner lumen extending along the longitudinal axis of the catheter tube, where the third inner lumen provides a return conduit for arterial flow from the flowmeter, and is in fluid communication with a second opening (output opening) positioned on the catheter tube.

2. An arterial flow measurement system in accordance with claim 1, wherein the fluid guide element is positioned between a proximal tip of the catheter and the first opening.

3. An arterial flow measurement system in accordance with claim 1, wherein the first cross-sectional diameter is smaller than the second cross-sectional diameter.

4. An arterial flow measurement system in accordance with claim 1, wherein the fluid guide element has a concave distal part facing the distal end of the catheter tube, where the concave part is configured to guide at least part of the surrounding arterial flow into the first opening.

5. An arterial flow measurement system in accordance with claim 3, wherein the concave distal part is connected to a part of the catheter tube that is between a proximal end of the catheter and the first opening.

6. An arterial flow measurement system in accordance with claim 17, wherein the fluid guide element is an inflatable balloon connected to the conversion element of the catheter.

7. An arterial flow measurement system in accordance with claim 17, wherein the conversion element has a second inner lumen providing fluid communication along the longitudinal axis of the catheter tube, where the second inner lumen is in fluid communication with the fluid guide element.

8. An arterial flow measurement system in accordance with claim 1, wherein the first inner lumen of the catheter tube is in fluid communication with the flowmeter via an arterial flow tube, where the arterial flow tube has a proximal end connected to the first inner lumen of the catheter and a distal end connected to the flowmeter.

9. An arterial flow measurement system in accordance with claim 1, wherein the second opening is positioned proximally to the first opening and/or the fluid guide element.

10. An arterial flow measurement system in accordance with claim 1, wherein the second opening is positioned on a terminal proximal end of the catheter tube, optionally where a central axis of the second opening is coaxial with the longitudinal axis of the catheter tube.

11. An arterial flow measurement system in accordance with claim 1, wherein a central axis of the first opening is perpendicular to the longitudinal axis of the catheter tube.

12. An arterial flow measurement system in accordance with claim 1, wherein the first inner lumen, second inner lumen and/or third inner lumen are separated from each other.

13. An arterial flow measurement system in accordance with claim 1, wherein in input part of the flowmeter is in fluid communication with the first lumen of the catheter tube, and/or an output part of the flowmeter is in fluid communication with the third inner lumen.

14. An arterial flow measurement system in accordance with claim 1, wherein the distal end of the catheter tube comprises a first connector for the first internal lumen, a second connector for the second internal lumen and/or a third connector for the third internal lumen.

15. (canceled)

16. (canceled)

17. An arterial flow measurement system in accordance with claim 1, further comprising a conversion element, where the conversion element is connected to the fluid guide element allowing a user to selectively transform the fluid guide element from an insertion state to a measuring state, and vice versa.

18. An arterial flow measurement system in accordance with claim 1, wherein the fluid guide element has an insertion state where the fluid guide element has a first cross-sectional diameter and in a measuring state where the fluid guide element has a second cross-sectional diameter.

19. An arterial flow measurement system in accordance with claim 18 wherein: the arterial flow measurement system comprises a conversion element, where the conversion element is connected to the fluid guide element allowing a user to selectively transform the fluid guide element from an insertion state to a measuring state, and vice versa; and the conversion element has a second inner lumen providing fluid communication along the longitudinal axis of the catheter tube, where the second inner lumen is in fluid communication with the fluid guide element, to allow the selectively conversion of the fluid guide element from the insertion state to the measuring state, and vice versa.

20. A method of measuring arterial flow in an artery, the method comprising: inserting a catheter tube having a longitudinal axis, a proximal end and a distal end, a first inner lumen providing fluid communication along the longitudinal axis of the catheter tube, a first opening (input opening) configured to provide fluid communication from the outside of the catheter tube and into the first inner lumen through a side wall of the catheter tube, and a fluid guide element configured to guide at least part of an arterial flow surrounding the fluid guide element into the first opening; and extracting arterial blood along the first inner lumen and into a flowmeter, where the flowmeter measures the flow rate of the blood entering the flowmeter.

21. A method in accordance with claim 20, wherein the fluid guide element comprises an insertion state where the fluid guide element has a first cross-sectional diameter, and a measuring state where the fluid guide element has a second cross-sectional diameter.

22. A method in accordance with claim 21, wherein catheter tube comprises a conversion element, where the conversion element is connected to the fluid guide element allowing a user to selectively transform the fluid guide element from the insertion state to the measuring state, and vice versa, wherein the method further comprises: converting the fluid guide element to a measuring state where the fluid guide element guides the arterial blood into the first opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The following is an explanation of exemplary embodiments with reference to the drawings, in which

[0040] FIG. 1 is a perspective frontal view of a catheter,

[0041] FIG. 2 is a perspective rear view of a catheter,

[0042] FIGS. 3a and 3b are side views of a catheter in an measurement state and a insertion state, respectively,

[0043] FIG. 4 is a side sectional view of a catheter, and

[0044] FIG. 5 is a schematic view of a arterial flow measurement system.

DETAILED DESCRIPTION

[0045] FIG. 1 and FIG. 2 show a front perspective view and a rear perspective view of a catheter 1, respectively. The catheter 1 comprises a catheter tube 2 having a proximal end 3 and a distal end 4. The catheter 1 may comprise a fluid guide 5, where the fluid guide 5 extends around the circumference of the catheter tube 2, and provides an area of a catheter 1, i.e. the fluid guide, where the catheter 1 has an increased diameter. The fluid guide 5 has a proximal part 6 and a distal part 7, where the proximal part 6 of the fluid guide faces the proximal end 3 of the catheter tube 2 and the distal part 7 of the fluid guide 5 faces the proximal end 3 of the catheter tube 2. The distal part 7 of the fluid guide 5 may have a collection volume 8, where the collection volume 8 may be a concave part, where a distal peripheral edge 9 of the fluid guide extends in a direction closer to the distal end 3 of the catheter tube 2 than an inner radial part 10, which abuts the catheter tube 2. The collection volume 8 of the fluid guide 5 is configured to face the flow direction of arterial blood, so that the blood is adapted to be captured in the collection volume 8.

[0046] The catheter tube 2 may comprise a first lumen 11, which extends along the length of the catheter tube 2, where the first lumen 11 terminates in a first opening 12, which abuts the inner radial part 10 of the fluid guide 5 in a distal direction, so that the blood that is collected in the collecting volume 8, may be diverted into the first opening 12, allowing the blood to be directed out of the artery, via the first opening 12 and along the first lumen 11 in a proximal direction. The first lumen 11, may be in fluid connection with an input of a flowmeter (not shown) to measure the flow of blood through the first lumen 11.

[0047] The catheter tube 2, may comprise a third lumen 13, which extends along the length of the catheter tube 2, where the third lumen 13 terminates in the proximal end 3 of the catheter tube 2, in the form of a second opening 14. The third lumen 13 may be a fluid communication to an output of a flowmeter (not shown) inside the catheter tube, where the third lumen 13 may be utilized to return blood back to an artery after the blood has been diverted out of an artery, where the blood exits the second opening 14 in a direction that is in parallel to the blood flow inside the artery.

[0048] The catheter tube 2, may comprise a second lumen 15, where the second lumen 15 may be in fluid communication with the fluid guide 5, where the second lumen 15 may be utilized to accommodate a conversion element that is capable of providing means of transitioning the fluid guide 5 from an insertion state (shown in FIG. 3b), to a measurement state (shown in FIG. 3a). The fluid guide 5 may be a shaped balloon 16, where the shape of the balloon in a measurement state is the form shown in the present disclosure, allowing the fluid guide 5 to guide the flow of fluid into the first opening 12.

[0049] FIG. 3a shows the catheter 1, where the fluid guide 5 is in a measurement state, i.e. in an expanded state. When the fluid guide 5 is in a measurement state, the cross-sectional diameter A of the fluid guide 5 is larger than the cross-sectional diameter B of the catheter tube 2, where the increased diameter means that flow of blood in a direction C can be collected inside the collecting volume 8, and guided towards the first opening (not shown).

[0050] FIG. 3b shows the catheter 1, where the fluid guide 5 is in a insertion state, i.e. in a collapsed state. When the fluid guide 5 is in an insertion state, the cross-sectional diameter D of the fluid guide 5 is substantially equal to the cross-sectional diameter B of the catheter tube, where the collapsed fluid guide 5 means that the fluid guide does not interfere with the flow of blood in a direction C more than the catheter tube 2 does. The insertion state of the fluid guide 5 may also be utilized, when the catheter 1 is to be extracted from an artery.

[0051] FIG. 4 shows a cross-sectional schematic view of a catheter 1 which is introduced into an artery 16, where the fluid guide 5 is in its measurement state, i.e. in an expanded state, where the cross-sectional diameter of the fluid guide 5 is larger than the cross-sectional diameter of the catheter tube 2. The flow of blood inside 17 the artery may be seen as the distal flow C1 and the proximal flow C2, where the distal flow C1 may be seen as the flow which the fluid guide can intersect, while the proximal flow C2 may be seen as the flow which passes the fluid guide 5 and also the blood flow which exits the second opening 14, in a direction E, where the direction E may be the same direction as the flow directions C1 and C2.

[0052] The blood flow C1 may be collected inside the collecting volume 8 of the fluid guide 5, where the blood may be guided into the first opening 12, where the flow of blood may be seen as reversing in a direction F inside the first lumen 11, which is an opposite direction to the direction C1, where the first lumen may be fluid communication with a flowmeter (not shown) which is capable of measuring the flow of blood inside the first lumen 11. When the flowmeter (not shown) has measured the blood flow, the blood may be returned via the third lumen 13, and exits the catheter at its proximal end 3 through the second opening 14, which returns the blood into the inner volume 17 of the artery 16.

[0053] The catheter 1 also comprises a second lumen 15, where the second lumen 15 is in fluid communication with an inner volume 18 of the fluid guide 5, where the fluid communication may e.g. be through a third opening 19, which allows fluids to pass from the second lumen 15 and into the inner volume 18 of the fluid guide 5. The fluid guide 5 in this example may be an inflatable balloon, which may be inflated and deflated by communicating a fluid in the both a proximal direction and a distal direction, as shown with arrow G, to selectively inflate and/or deflate the inner volume 18 of the fluid guide 5, to transform the fluid guide 5 from an insertion state to a measurement state (as shown in FIGS. 3a and 3b).

[0054] FIG. 5 shows a schematic diagram of a system 100 for measuring flow in an artery 108 and/or a vein 108 inside the body 102, where the flowmeter 104 may be positioned outside 106 the body. A part of the blood flow 110 may be diverted from the artery 108 and into a flowmeter 104, where the diverted blood flow 110 may be returned 114 back into the artery 108, when the flow of the diverted blood flow 110 has been measured by the flowmeter.

[0055] The calculations regarding the measured flow in the system 100 may be influenced by a resistance in the system, where resistance may be divided into resistance R1, which is the resistance in the tubes diverting the blood from the artery 108, resistance R2 which is the resistance in the flowmeter, resistance R3 which is the resistance in the fluid communication leading the blood flow back into the artery 108, resistance R4 which may be the resistance of inside the artery 108 due to the insertion of the catheter and/or the resistance R5 which may be the resistance in microcirculation 116 which is in fluid communication with the artery. If the resistances in the system 100 may be measured or calculated the flow measured in the flowmeter may be mathematically transformed to represent the actual flow in the artery. The shape and size of the fluid guide and the catheter will influence the measurements, and by performing tests and experiments the correlation between the fluid guide and the collected flow of blood may be established, to assist in the calculation of the blood flow through the artery.

[0056] The use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not imply any particular order, but are included to identify individual elements. Moreover, the use of the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. does not denote any order or importance, but rather the terms “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used to distinguish one element from another. Note that the words “first”, “second”, “third” and “fourth”, “primary”, “secondary”, “tertiary” etc. are used here and elsewhere for labelling purposes only and are not intended to denote any specific spatial or temporal ordering.

[0057] Furthermore, the labelling of a first element does not imply the presence of a second element and vice versa.

[0058] It is to be noted that the word “comprising” does not necessarily exclude the presence of other elements or steps than those listed.

[0059] It is to be noted that the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements.

[0060] It should further be noted that any reference signs do not limit the scope of the claims, that the exemplary embodiments may be implemented at least in part by means of both hardware and software, and that several “means”, “units” or “devices” may be represented by the same item of hardware.

[0061] Although features have been shown and described, it will be understood that they are not intended to limit the claimed invention, and it will be made obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the claimed invention. The specification and drawings are, accordingly to be regarded in an illustrative rather than restrictive sense. The claimed invention is intended to cover all alternatives, modifications, and equivalents.