WO2022064491A1

WO2022064491A1 - Hi flow rate and/or multi-lumen cannula

Info

Publication number: WO2022064491A1
Application number: PCT/IL2021/051151
Authority: WO
Inventors: Mohammad Sarraf; Reuven FILMAN; Paulo NEVES; Moshe LICHTENSTEIN
Original assignee: Gross, Amir; Maisano, Francesco
Priority date: 2020-09-24
Filing date: 2021-09-22
Publication date: 2022-03-31

Abstract

Some embodiments relate to a cannula configured to facilitate high flow rates. For example, a cannula may foster vortex flow (e.g., a spiral vortex along an axis of a tube and/or spiral flow along a pipe). Optionally, the cannula may include rifling and/or a funnel section and/or a spiral vortex generating section and/or multiple openings. Alternatively, or additionally, cannula stiffness may be adjusted e.g., to discourage sharp bends and/or changes in pressure. Some embodiments relate to a multi-lumen cannula wherein at the distal end of the cannula the lumens diverge in a way that fits a geometry of a target of flow from the separate lumens. For example, a lumen (e.g., a perfusion lumen) of the cannula may extend beyond a second lumen (e.g., a drainage lumen). Optionally, the extended lumen may be configured to bend at a predetermined angle with respect to the second lumen.

Description

APPLICATION FOR PATENT

Hi Flow Rate and/or Multi-Lumen Cannula

RELATED APPLICATION/S

This application claims the benefit of priority under 35 USC §119(e) of U.S. Provisional Patent Application No. 63082475 filed 24 Sept. 2020, the contents of which are incorporated herein by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to a cannula and, more particularly, but not exclusively, a cannula for high flow rate applications optionally having multiple lumens.

U.S. Patent no. 6685664 appears to disclose, “Method and apparatus for the extracorporeal treatment of blood by utilizing a peripherally inserted catheter assembly for the continuous removal of blood for renal replacement treatment, in particularly, treatment of congestive heart failure and fluid overload by ultrafiltration. A catheter is inserted in a peripheral vein and maneuvered upward through the vascular system to access the reservoir of blood in the large or great veins for continuous blood withdrawal and treatment. Air-tight connectors are incorporated in the catheter assembly to overcome the untoward effects of negative pressure in blood withdrawal.”

U.S. Patent Publication no. US20050192558 appears to disclose, “A peripherally inserted catheter assembly having multiple side holes to be inserted in a peripheral vein and maneuvered upward through the vascular system to access the reservoir of blood beyond and between the venous flappers for continuous blood withdrawal and treatment.”

U.S. Patent no. 5738649 Appears to disclose, “a closed chest intravascular catheter system for a simultaneous biventricular approach to 1) intravascular cardiopulmonary surgery and 2) acute or prolonged mechanical circulatory support.”

Additional background art includes, Daniel Goldstein et al., "Venoarterial Shunting for the Treatment of Right Sided Circulatory Failure After Left Ventricular Assist Device Placement", ASAIO Journal 1997, pp. 171-176. Giulio Russo, MD; Maunzio Taramasso, MD, PhD; and Francesco Maisano, MD; Transseptal Puncture: A Step-by-Step Procedural Guide; CARDIAC INTERVENTIONS TODAY MAY/JUNE 2019 VOL. 13, NO. 3, pg. 22. Jonas Andersson Lindholm; Cannulation for veno-venous extracorporeal membrane oxygenation; Journal of Thoracic Disease 2018;10(Suppl 5): S606-S612.

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

SUMMARY OF THE INVENTION

According to an aspect of some embodiments of the invention, there is provided a cannula including: an elongated flexible body a main lumen along a length of the body; a vortex generator for generating vortex flow associated with the main lumen.

According to some embodiments of the invention, the elongated flexible body is configured for insertion into a mammal.

According to some embodiments of the invention, the cannula of claim 1, further includes a positioning feature.

According to some embodiments of the invention, the positioning feature includes a ridge.

According to some embodiments of the invention, the first vortex generator includes rifling along a length of the main lumen.

According to some embodiments of the invention, the rifling includes a protrusion from an inner wall of the lumen.

According to some embodiments of the invention, the rifling includes a groove in an inner wall of the lumen.

According to some embodiments of the invention, the first vortex generator includes an entrance chamber at an inlet of the lumen.

According to some embodiments of the invention, the cannula further includes: a secondary lumen. According to some embodiments of the invention, the secondary lumen includes a second vortex generator.

According to some embodiments of the invention, the secondary lumen extends distally past the main lumen.

According to some embodiments of the invention, the Camilla further compromising an entrance chamber.

According to some embodiments of the invention, the entrance chamber is shaped for funneling flow.

According to some embodiments of the invention, the cannula has multiple lumens including a first lumen configured for insertion into a right atrium and a second lumen configured for insertion into a left atrium.

According to an aspect of some embodiments of the invention, there is provided a method of opening channels to a first chamber and a second chamber in- vivo including: supplying a catheter having a first and a second lumen; Inserting a distal end of the catheter into the first chamber; supplying an opening to the first lumen in the first chamber; extending a distal end of an extension canella from the catheter into the second chamber; and supplying an opening to the second lumen through the extension canella in the second chamber.

According to some embodiments of the invention, the method further includes extracting fluid from the first chamber and injecting fluid into the second chamber.

According to some embodiments of the invention, the inserting is into a right atrium.

According to some embodiments of the invention, the extending is into a left atrium.

According to some embodiments of the invention, the method further includes: inhibiting overinsertion of the extension canella.

According to some embodiments of the invention, the inhibiting includes causing a tactile sensation at a completion of insertion.

According to some embodiments of the invention, the method further includes: directing a outlet hole of the extension canella towards a mitral valve.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

In the drawings: FIG. 1 is a block diagram illustration of a cannula configured for augmented flow in accordance with an embodiment of the current invention;

FIG. 2 illustrates a multi-lumen cannula in accordance with an embodiment of the current invention;

FIG. 3 is a block diagram of a cannula in accordance with an embodiment of the current invention;

FIG. 4 is a flow chart of a method of transporting fluid into and/or out of a body in accordance with an embodiment of the current invention;

FIG. 5A is a flow chart illustration of a method of inserting a multi-lumen cannula in accordance with an embodiment of the current invention;

FIGs. 5B and 5C are flow chart illustrations of inserting a transseptal cannula for extracorporeal membrane oxygenation ECMO into a heart of a subject in accordance with embodiments of the current invention;

FIG. 6 is a schematic illustration of a rifled pattern along the inner surface of a lumen in accordance with an embodiment of the current invention;

FIGs. 7A and 7B are schematic illustrations of protruding rifling features in a lumen in accordance with an embodiment of the current invention;

FIGs. 7C and 7D are schematic illustrations of rifling grooves in a lumen in accordance with an embodiment of the current invention;

FIG. 8A, 8B and 8C are a schematic illustration of a distal end of a multilumen cannula in accordance with an embodiment of the current invention;

FIG. 9 is a schematic illustration of a rifled cannula 2 with and entrance chamber 1 in accordance with an embodiment of the current invention;

Fig. 10 illustrates a cannula with multiple entrance openings positioned to encourage vortex flow in accordance with an embodiment of the current invention;

FIGs. 11 to 14 illustrate alternative cross-sectional geometries for a multilumen cannula in accordance with the current invention;

FIG. 15 is a schematic perspective illustration of a multi -lumen cannula having a feature for positional feedback in accordance with an embodiment of the current invention;

FIG. 16 is a schematic cutaway illustration of a multi-lumen cannula having a feature for positional feedback in accordance with an embodiment of the current invention; and FIG. 17 is a schematic illustration of a cannula having features fitting geometry of a target in accordance with an embodiment of the current invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

OVERVIEW

An aspect of some embodiments of the current invention relates to a cannula configured to facilitate high flow rates. For example, the cannula may include one or more lumens designed to foster a low resistance flow regime. For example, a cannula may be designed to foster vortex flow (herein vortex flow refers to ordered flow, for example with a spiral vortex along an axis of a tube, for example spiral flow along a pipe). For example, the vortex flow may remain ordered and/or have lower flow resistance than fully laminar flow. For example, vortex flow may be sustainable at higher Reynolds numbers than simple laminar flow. Optionally, the cannula may include rifling and/or a funnel section and/or a spiral vortex generating section and/or an opening that promotes vortex flow. For example, the funnel and/or vortex generating section may be at an entrance to the cannula. Alternately or additionally, the inner walls of a portion of a cannula and/or the entire cannula may be rifled. Additionally, or alternatively, the cross-sectional shape of a lumen may be designed to reduce flow resistance. For example, multiple lumens of a multi-lumen cannula may be shaped to balance resistance and flow between the lumens and/or the lumens may be shape to encourage low resistance flow regimes (for example they may be shaped circularly or near circularly to encourage vortex flow). Alternatively, or additionally, cannula stiffness may be adjusted to discourage sharp bends on it that may increase flow resistance.

An aspect of some embodiments of the current invention relates to a multilumen cannula wherein at the distal end of the cannula the lumens diverge in a way that fits a geometry of a target of flow from the separate lumens. For example, a lumen (e.g., a perfusion lumen) of the cannula may extend beyond a second lumen (e.g., a drainage lumen). Optionally, the extended lumen may be configured to bend at a predetermined angle with respect to the second lumen. Optionally, a lumen may include a marker (for example, near a distal end thereof) for determining the correct positioning of that lumen and/or other lumens and/or the entire cannula.

In some embodiments, the shape and/or flow characteristics and/or mechanical properties of a cannula and/or one or more lumens may be configured to support a desired flow rate under expected conditions within a mammalian body. For example, the flow may be supported under unsteady flow and/or under available pressures and/or along a twisted path of the cannula through the body and/or within limited space. In some embodiments the locations of entrances of the lumens may reflect the geometry of the body. For example, one lumen may extend past and/or at angle to another lumen.

SPECIFIC EMBODIMENTS

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

FIG. 1 is a block diagram illustration of a cannula configured for augmented flow in accordance with an embodiment of the current invention. In some embodiments, a cannula may include a flexible cannula 102. For example, the cannula 102 may be configured for insertion into a mammalian body. Optionally, the cannula 102 includes a vortex generator 104 configured to promote vortex flow within the cannula 102. Optionally, the vortex flow may be adjusted according to the expected flow in the cannula. For example, the direction and/or the angle of spiraling may be adjusted according to the direction and/or speed of flow in the cannula 102 and/or the angle to which the cannula 102 is bent and/or the steadiness/unsteadiness of flow.

In some embodiments, a vortex generator 104 may include rifling on the inside of the cannula. For example, the rifling may include protrusions or channels in an inner wall of the cannula 102. For example, channels may be extruded from the wall. Optionally the rifling may spiral only the inner wall of the cannula. Alternatively, or additionally, the shape and/or position of inlets to the cannula may be configured to promote vortex flow. Alternatively, or additionally, the shape of the entrance of the cannula 102 may be configured to promote vortex flow. Alternatively, or additionally, the vortex generator 104 may include a vortex generating addition at a distal end of the cannula 102.

In some embodiments, the cannula 102 may be made with and/or coated with biologically compatible material and/or may be sterile and/or may be designed for easy cleaning and/or sterilization and/or may be designed for one-time use and/or packaged in a sterile packaging.

In some embodiments, the cannula 102, may include one or more channels. For example, the channels may be configured according to the desired flow regime. For example, as described in various embodiments herein below.

Optionally a cannula may have a French size of between 1 to 5 and/or between 5 to 10 and/or between 10 to 15 and/or between 15 to 18 and/or between 18 to 25 French.

FIG. 2 illustrates a multi-lumen cannula in accordance with an embodiment of the current invention. For example, a multi-lumen cannula may be configured to inject and/or extract fluids to and/or from a mammalian subject in accordance with an embodiment of the current invention. In some embodiments, a cannula includes an outer cannula 202. Optionally, the outer cannula may include multiple lumens 206a, 206b. In some embodiments, the shape of the lumens’ 206a, 206b may be configured to fit an internal geometry of the subject. For example, the distal end of the lumens may diverge to reach different portions of the subject. For example, the flow characteristics of the lumens 206a, 206b may be configured to support a preferred flow regime under geometric and/or hydraulic limitations of the subject. For example, the flow regime may account for available pressure, twisting of the lumen 206a, 206b as it passes through the subject, changes in flow over time etc. For example, the distal end of the cannula may be designed to facilitate inserting an entrance of one lumen 206a into one location in the subject (for example a right atrium of the heart) with an entrance of a second lumen 210 extending further and/or angled towards into a second location (for example, a left atrium of the heart).

In some embodiments, a cross section of the cannula may be arranged to support a flow regime. For example, the hydraulic diameter of each lumen 206a, 206b may be configured to support a desired flow rate powered by a pressure drop between fluid source outside the subject and/or a fluid source inside the subject. For example, some fluid will be drawn out of the subject at a desired flow rate based on an internal pressure inside the body and/or fluid will be pumped back into the body at a similar flow rate using an artificial pump outside the subject. For example, the artificial pump may create a head difference greater than the subject’s internal body pressure. For example, the lumen 206a for flow from the body may have a larger hydraulic radius and/or more flow resistance than the lumen 206b for flow into the body.

In some embodiments, a cannula may include a marker. For example, a marker may be used to determine the position of a portion of the cannula inside a subject. For example, a marker may be configured to cause a tactile sensation and/or to be detectable using a machine (e.g., a fluoroscope and/or a radiation sensor). For example, a lumen cannula may include a ridge that causes a change in resistance to movement as the cannula is moved through a constriction.

In some embodiments, one or more of the lumens may include a flow enhancement, for example, a feature configured to promote vortex flow.

FIG. 3 is a block diagram of a cannula in accordance with an embodiment of the current invention. In some embodiments, cannula 302 may have a flow enhancing addition. For example, there may be a pulsation reducer 304. For example, an elastic portion of the cannula 302 may absorb energy when there is a high-pressure pulse and/or redistribute the energy over time. For example, redistributing the energy may help prevent flow from becoming disordered due to temporal fluctuations and/or redistributing energy may help keep high flow rates over the entire flow cycle giving a higher average flow rate.

FIG. 4 is a flow chart of a method of transporting fluid into and/or out of a body in accordance with an embodiment of the current invention. In some embodiments, a cannula is inserted 402 into a subject. Optionally, ordered flow is induced 404 in the cannula. For example, the cannula may be shaped to induce laminar flow and/or reduce turbulence and/or induce vortex flow and/or reduce flow fluctuation over time and/or reduce changes in flow resistance along the cannula (for example by reducing the sharpness of curves and/or configuring the cannula to take a low resistance shape when it curves. Optionally the cannula will be used for enhanced transport 406 of fluids into and/or out of the subject.

FIG. 5A is a flow chart illustration of a method of inserting a multi-lumen cannula in accordance with an embodiment of the current invention. In some embodiments, a guidewire is inserted and/or positioned 508a in a desired target. Optionally a cannula is then inserted 502a over the guidewire to the target. In some embodiments, the guidewire may be further positioned 502b to the furthest location of the cannula and/or an extended beyond the lumen. Optionally, an extension of catheter may be positioned 510a further to a desired location. For example, the extended lumen of the cannula may be positioned 510a around the guidewire to the desired location. Optionally, once the extended lumen has been positioned 510a, the location of the cannula may be adjusted to position an opening of the extended cannula and/or a second cannula in a desired location. In some embodiments, once the cannula and/or extended cannula are positioned, the guidewire may be removed 512. Optionally, the position of the cannula and/or extended cannula may be adjusted, for example to position 514a an entrance hole thereof in a desired location.

FIGs. 5B and 5C are flow chart illustrations of inserting a transseptal cannula for extracorporeal membrane oxygenation ECMO into a heart of a subject in accordance with embodiments of the current invention. For example, the cannula may include a distal perfusion port and/or a drainage port. For example, the perfusion port may be placed in the left atrium and/or drainage port in the right atrium. The ECMO cannula may include features illustrated in various embodiments described herein. In some embodiments, a cannula may be used for ECMO.

In some embodiments a transseptal puncture is performed 518. For example, the transseptal puncture may be performed 518 using standard techniques. Imaging may be used for example by means of a fluoroscope and/or Transesophageal Echocardiogram (TEE). A guidewire is optionally advanced 508b into the left atrium LA. Optionally, an outer cannula may be positioned 502b with an opening of one lumen in the right atrium RA. Additionally or alternatively, an extension of the cannula is extended 510b into the left atrium LA. For example, some steps in insertion of the cannula may include:

Perform a percutaneous echo guided puncture in the femoral vein and or jugular vein; Under transesophageal echocardiography TEE and/or fluoroscope, perform 518 a transseptal puncture;

Advance 508b a stiff wire in the LA, place it on left superior pulmonary vein;

Advance a veno-venous VV cannula over the wire with external markings properly directed (e.g., at 12 o’clock) to ensure proper drainage hole alignment. For example, the drainage hole may be placed in right atmim and/or directed 514c toward inferior vena cava. Optionally, an outlet hole is placed 510b into the left atrium and/or the outlet hole is directed 514b towards the mitral valve. In some embodiments, (e.g., as illustrated in FIG. 5C) a second cannula is placed 510c into the common femoral artery. Optionally the procedure is performed under TEE and/or fluoroscopic guidance. Optionally, there will be a backstop mechanism will inhibit 520 over insertion. After insertions, and/or once the introducer is removed 512, the lumens may optionally be flushed and/or connected 526a, 526b to an extracorporeal membrane oxygenation ECMO circuit. For example, the drainage port may be connected 526a to a venous line and/or the outlet port may be connected 526a to an arterial line. Alternatively or additionally, (e.g., as illustrated in FIG. 5C), connection 526b to the ECMO may include connecting 526b both ports of the VV cannula to a venous line (for example using a Y-connector). Additionally or alternatively, the femoral and/or an arterial cannula may be connected 526b to an arterial line. Optionally, once connected 526a, 526b, the system may start pumping.

FIG. 6 is a schematic illustration of a rifled pattern 630 along the inner surface of a lumen 602 in accordance with an embodiment of the current invention. In some embodiments rifling may be machined and/or etched into an inner wall of a lumen. Alternatively, or additionally, rifling may include features that are added to an inner wall of the lumen 602. Alternatively, or additionally, rifling may be formed on an inner wall of a lumen 602 by applying force and/or chemicals to an outer wall of the lumen 602. Alternatively, or additionally, a lumen 602 may be formed with rifling. For example, a cannula may be formed by molding and/or extrusion and/or the inner wall of the lumen 602 may be formed with rifling features. For example, rifling may include spiral grooves and/or protrusions along the inner wall of the lumen.

In some embodiments, a rifling groove and/or protrusion may have a height that is between 1/10 and 1/50 of the hydraulic radius of the lumen and/or between 1/5 and 1/10 and/or between 1/50 to 1/200 and/or between 1/200 to 1/500. In some embodiments rifling will only be on a portion of the lumen, for example rifling for example between 100% to 50% of the length of the lumen and/or between 10 to 50% and/or between 1 to 10%. Optionally, the rifling will be near an entrance to the lumen and/or distributed along the lumen. Optionally the rifling will twist 1 full rotation over between 0. 1 to 1 cm of length and/or between 1 to 3 cm and/or between 3 to 10 cm of length and/or between 10 to 30 cm and/or 30 to 200 cm. For example, the rifling length may be proportional to the hydraulic radius of the lumen and/or to the flow rate for which the lumen is designed.

FIGs. 7A and 7B are schematic illustrations of protruding rifling features 730a in a lumen 702a in accordance with an embodiment of the current invention.

FIGs. 7C and 7D are schematic illustrations of rifling grooves 730b in a lumen 702b in accordance with an embodiment of the current invention.

FIG. 8A, 8B and 8C are a schematic illustration of a distal end of a multilumen cannula 802 in accordance with an embodiment of the current invention. Optionally, cannula 802 includes a first lumen 832a that extends as an extended cannula 810 past a second lumen 832a. For example, blood may flow into the second drainage lumen 832a from a right atrium and/or blood may exit the cannula 802 through a first extended perfusion cannula 810 into a left atrium (e.g., as illustrated in FIG. 17). Optionally each lumen 832a, 832b includes a distal opening 834a, 834b and/or one or more auxiliary openings 835a, 835b along a distal portion (e.g., the distalmost 0.25 cm and/or 0.5 cm and/or 1 cm and/or 2 cm and/or 4 cm and/or 8 cm). Optionally one or both of the lumens 832a, 832b includes features 804 to foster ordered flow (for example rifling to foster vortex flow).

One or more openings 834a, 834b, 835a, 835b to a lumen 832a, 832b may supplied. The position and/or size of the openings 834a, 834b, 835a, 835b may be intended to fit geometry of a target organ and/or to support a desired flow rate and/or to foster a desired flow regime.

Optionally the inner cannula extends 810 a past the distal end of the outer cannula 802. For example, the inner cannula may extend between 0.1 to 0.5 cm and/or between 0.5 to 1.0 and/or 1.0 to 2.0 and/or 2.0 to 5.0 and/or 5.0 to 10 cm beyond the distal end of the outer cannula 802. For example, the extension of inner cannula 810 may be biased to make an angle with the outer cannula 802. For example, the angle may range between 1 to 15 degrees and/or between 15 to 30 degrees and/or between 30 to 45 degrees and/or between 45 to 60 degrees and/or between 60 to 90 degrees and/or between 90 to 120 degrees. In some embodiments, this angulation is only evident without the introducer. For example, the introducer may straighten the cannula, facilitating its insertion. In some embodiments, openings 834a, 834b, 835a, 835b to a lumen 832a, 832b may include one or more port hole type openings 835a, 835b on the side of the limen and/or an end opening 834a, 834b. For example, none of the lumens, one lumen 832a, 832b, multiple lumens 832a, 832b and/or all of the lumens 832a, 832b may include have one opening 834a, 834b, 835a, 835b or more. The openings 834a, 834b, 835a, 835b may be arranged to in order to have redundancy, increase flow rate and/or reduce flow resistance.

FIG. 9 is a schematic illustration of a rifled cannula 902 with and entrance chamber 936 in accordance with an embodiment of the current invention. The cannula 902 assembly may contain dedicated portion vortex generating chamber 936 as part of the cannula 902 or attached to the cannula 902 that may generate vortex. For example, the chamber 936 may generate the vortex flow shorter and/or quicker than it would be done inside the cannula 902.

In some embodiments, the entrance chamber 936 may include rifling 904a, for example, to initiate vortex flow before the entrance of the cannula 902. Optionally the entrance chamber 936 may funnel flow and/or increase flow order and/or decrease flow unsteadiness as flow enters the cannula 902. For example, the entrance chamber 936 may include an elastic element. Optionally, the rifling 904a in the entrance chamber 936 may be stronger than rifling 904b in the cannula 902.

Fig. 10 illustrates a cannula 1002 with multiple entrance openings 1034, 1035a, 1035b positioned to encourage vortex flow 1038 in accordance with an embodiment of the current invention. For example, entrance openings 1034, 1035a, 1035b may be directed at angles to the axis of the cannula 1002 and/or may be positioned along the cannula 1002 to foster vortex flow 1038. For example, in the example of FIG. 10, fluid entering into entrance 1034 is pushed rightward in a spiraling pattern by fluid entering in entrance 1035a and/or entrance 1035b. For example, entrance 1034 may be off center to the cannula 1002 and/or entrance 1035a and entrance 1035b may be arranged in a spiral pattern along the length of the cannula 1002.

FIGs. 11 to 14 illustrate alternative cross-sectional geometries for a multilumen cannula in accordance with the current invention. In some embodiments, the cross section of one or more lumens of a cannula may be adjusted to improve flow performance. For example, a geometry may be selected to achieve a large hydraulic radius and/or to encourage an ordered flow regime. For example, the lumens 1132a, 1132b, 1232a, 1232b of the cannulas 1102, 1202 ofFIGs. 11 and 12 are shaped to achieve a large flow space and/or large hydraulic radius for each of a plurality of lumens. In some, embodiments, a discontinuity in the boundary of the flow domain may be adjusted (for example rounding a sharp comer 1142) to reduce the creation of disordered flow and/or free vortexes and/or turbulence (for example as illustrated in FIG. 11). In some embodiments, a cross section may be rounded (for example as illustrated in FIG. 12) to encourage ordered flow (for example vortex flow). Such rounding may improve flow characteristics even where is reduces the hydraulic radius. In some embodiments, where flow geometries (e.g., a rounded lumens 1232a, 1232b, 1332a, 1332b that increases ordering) results in wasted space (e.g., as illustrated in FIG. 12) an extra lumen 1332c may be added (e.g., as illustrated in FIG. 13). For example, flow in one direction may be directed through multiple round channels rather than through one larger channel having discontinuities. Optionally, multi-lumens are tuned to achieved balanced flow. For example, for a flow cannula suppling a similar rate of inflow and outflow, the inflow lumen may have more resistance to flow (e.g., be smaller) than the outflow lumen (e.g., because flow in the outflow lumen is powered by a small natural head drop while flow in an inflow lumen flow may be driven by and external pump and/or high head differential). Alternatively or additionally, sharp comers may be used to increase the area of flow for example as illustrated in lumens 1442a and 1442b of cannula 1402.

FIGs. 15 and 16 are schematic perspective and cutaway illustrations respectively of a multi-lumen cannula 802, 1510 having a feature for positional feedback in accordance with an embodiment of the current invention. For example, in some embodiments, a feature may give tactile feedback when a cannula 1510 reaches a desired location. For example, the extended cannula 1510 may include a ridge 1544. As the extended cannula 1510 passes through a tight space, there will be a change in resistance to movement as the ridge passes into or out of the tight zone. An operator may feel this change in resistance and understand that the extended cannula 1510 has reached a particular space. For example, when the cannula 1510 is being pushed through an incision, the change in resistance may be a sign the cannula 1510 has passed the incision and/or reached an intended space.

FIG. 17 is a schematic illustration of a cannula 802, 810 having features fitting geometry of a target in accordance with an embodiment of the current invention. For example, cannula 802, 810 of FIG. 17 may be designed for ECMO by drawing blood from a right atrium 1784 and returning the blood to the left atrium 1752. The distal portion of the cannula may be designed with an outer cannula 802 that is designed to access to the right atrium 1754 of a heart (for example the cannula 802 may have a length of between 10 to 35 cm and/or a width of between 2 to 5 French and/or between 5 to 9 and/or 9 to 15 and/or 15 to 18 and/or 18 to 25 French.

In some embodiments the extended cannula 810 may be sized to fit the right atrium 1784 and through an incision into the left atrium 1752. Optionally this may protect the patient and/or inhibit over insertion. For example, the extended cannula may be sized to extend 3 to 5 cm from the right atrium 1754 into the left atrium 1752. Optionally the extended cannula 810 is biased to an angle at between 5 to 45 degrees and/or between 15 to 30 degrees to the outer cannula. Optionally, while fit over a guidewire the extended cannula 810 may be bent approximately parallel to the cannula 802 or at another angle according to convenience, for example while sliding the cannula 802, 810 through the veins of the patient to the heart. In some embodiments, the entrance openings of the extended cannula are located on the inner side of the bent tube such that when the extended cannula 810 is inserted into the left atrium 1752, the openings point toward the left ventricle 1758 (e.g., towards the mitral valve 1756). The right ventricle 1760 is also illustrated.

GENERAL

It is expected that during the life of a patent maturing from this application many relevant building technologies, artificial intelligence methodologies, computer user interfaces, image capture devices will be developed and the scope of the terms for design elements, analysis routines, user devices is intended to include all such new technologies a priori.

As used herein the term “about” refers to ± 10%

The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

The term “consisting of’ means “including and limited to”.

The term "consisting essentially of means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

WHAT IS CLAIMED IS:

1. A cannula comprising: an elongated flexible body a main lumen along a length of said body; a vortex generator for generating vortex flow associated with said main lumen.

2. The cannula of claim 1, wherein said elongated flexible body is configured for insertion into a mammal.

3. The cannula of claim 1, of claim 1, further comprising a positioning feature.

4. The cannula of claim 3, wherein said positioning feature includes a ridge.

5. The cannula of claim 1, wherein said first vortex generator includes rifling along a length of said main lumen.

6. The cannula of claim 5, wherein said rifling includes a protrusion from an inner wall of said lumen.

7. The cannula of claim 5, wherein said rifling includes a groove in an inner wall of said lumen.

8. The cannula of claim 1, wherein said first vortex generator includes an entrance chamber at an inlet of said lumen.

9. The cannula of claim 1, further comprising: a secondary lumen.

10. The cannula of claim 9, wherein said secondary lumen includes a second vortex generator.

11. The cannula of claim 9, wherein said secondary lumen extends distally past said main lumen.

12. The Camilla of claim 1, further compromising an entrance chamber.

13. The cannulla of claim 12, wherein said entrance chamber is shaped for funneling flow.

14. The cannula of claim 13, wherein the cannula has multiple lumens including a first lumen configured for insertion into a right atrium and a second lumen configured for insertion into a left atrium.

15. A method of opening channels to a first chamber and a second chamber in- vivo comprising: supplying a catheter having a first and a second lumen;

Inserting a distal end of said catheter into the first chamber; supplying an opening to the first lumen in the first chamber; extending a distal end of an extension canella from said catheter into the second chamber; and supplying an opening to the second lumen through the extension canella in the second chamber.

16. The method of claim 15, further comprising extracting fluid from said first chamber and injecting fluid into said second chamber.

17. The method of claim 15, wherein said inserting is into a right atrium.

18. The method of claim 17, wherein said extending is into a left atrium.

19. The method of claim 18, further comprising: inhibiting overinsertion of said extension canella.

20. The method of claim 19, wherein said inhibiting includes causing a tactile sensation at a completion of insertion.

21. The method of claim 19, further comprising: directing a outlet hole of said extension canella towards a mitral valve.