Like reference symbols in the various drawings indicate like elements.
This disclosure relates to medical devices such as catheters that have multiple internal lumens. The cross-sectional areas of the multiple internal lumens can be changed, for example, by flowing fluids through one or more of the lumens.
In general, the length L of catheter 10 can be selected as desired. In some embodiments, L can be chosen according to a particular intended use for catheter 10, e.g., according to one or more physiological properties of a body lumen where catheter 10 will be inserted. In certain embodiments, L can be 1 mm or larger (e.g., 5 mm or larger, 10 mm or larger, 20 mm or larger, 30 mm or larger, 40 mm or larger). In some embodiments, L can be 300 cm or smaller (e.g., 20 cm or smaller, 100 cm or smaller, 50 cm or smaller, 1 cm or smaller). As an example, in some embodiments in which catheter 10 is an ocular drainage shunt, L can be 1 mm. As another example, in certain embodiments in which catheter 10 is employed in endoscopic use, L can be 300 cm.
In general, the outer diameter d of catheter 10 can be selected as desired. For example, the outer diameter d can be chosen so that the cross-sectional areas of each of the lumens in catheter 10 are sufficient to provide adequate fluid flow to or from a body site. In some embodiments, d can be 0.03 inch or larger (e.g., 0.05 inch or larger, 0.06 inch or larger, 0.07 inch or larger, 0.08 inch or larger). In certain embodiments, d can be 0.5 inch or smaller (e.g., 0.3 inch or smaller, 0.2 inch or smaller, 0.1 inch or smaller). As an example, in some embodiments in which catheter 10 is an ocular shunt, d can be 0.007 inch.
In general, the inner diameter i of catheter 10 can be selected as desired. For example, in some embodiments, i can be 0.03 inch or larger (e.g., 0.05 inch or larger, 0.06 inch or larger, 0.07 inch or larger, 0.08 inch or larger). In certain embodiments, i can be 0.5 inch or smaller (e.g., 0.3 inch or smaller, 0.2 inch or smaller, 0.1 inch or smaller). As an example, in some embodiments in which catheter 10 is an ocular shunt, i can be 0.005 inch.
The thickness tw of catheter material forming wall 15 can generally be selected as desired to impart particular flexibility and elasticity to lumen walls. In some embodiments, for example, tw can be 0.001 inch or larger (e.g., 0.002 inch or larger, 0.003 inch or larger, 0.005 inch or larger, 0.007 inch or larger, 0.01 inch or larger). In certain embodiments, tw can be 0.05 inch or smaller (e.g., 0.02 inch or smaller, 0.01 inch or smaller, 0.005 inch or smaller, 0.001 inch or smaller).
The thickness ts of material that forms septum 18 can generally be the same as tw or different from tw. For example, in some embodiments, ts can be less than tw so that, depending upon the catheter and septum materials, septum 18 can be more elastic than wall 15 of catheter 10 (e.g., elastic deformation of septum 18 under an applied force is larger than elastic deformation of wall 15). In some embodiments, ts can be 0.001 inch or larger (e.g., 0.002 inch or larger, 0.003 inch or larger, 0.005 inch or larger, 0.007 inch or larger, 0.01 inch or larger). In certain embodiments, ts can be 0.05 inch or smaller (e.g., 0.02 inch or smaller, 0.01 inch or smaller, 0.005 inch or smaller, 0.001 inch or smaller).
In general, the length s of septum 18 is greater than or equal to a maximum distance between two points on inner surface 14 of wall 15. In
In some embodiments, a ratio of the length s of septum 18 to the maximum distance between two points on inner surface 14 of wall 15 is at least 1:1 (e.g., at least 2:1, at least 3:1, at least 4:1, at least 5:1). In certain embodiments, the ratio of the length s of septum 18 to the maximum distance between two points on inner surface 14 of wall 15 is at most 10:1 (e.g., at most 9:1, at most 8:1, at most 7:1, at most 6:1, at most 5:1).
Wall 15 of catheter 10 can generally be formed from any of a variety of materials. Often, wall 15 is formed of a polymer. Examples of polymers include thermoplastic polyurethanes (e.g., thermoplastic polyurethanes based on polyesters, polyethers, polycarbonates, and polysiloxanes such as Tecoflex®, Tecothane®, and Bionate®), polyamides (e.g., polyamide 12, polyamide 11, nylon, polyamide 6-12), polyether block amide elastomers (e.g., PEBAX®), and polyolefins (e.g., EVA, high density polyethylene, medium density polyethylene, low density polyethylene, SBS, and SIBS). Different catheter materials can be selected according to the intended use of catheter 10. For example, if catheter 10 is intended for use as a venous access device, wall 15 can be formed from materials such as polyurethanes and/or silicones. As another example, if catheter 10 is intended for use as a cannula, wall 15 can be formed from materials such as nylons and/or polyether block amides. Optionally, wall 15 can be formed from a mixture of materials (e.g., a mixture of two or more of the materials noted above.)
In some embodiments, catheter 10 can include various types of additives in the material that forms wall 15. For example, the material can include radiopaque materials such as bismuth-containing materials (e.g., bismuth trioxide, bismuth bicarbonate, bismuth oxychloride, and other bismuth-containing materials), metals (e.g., tungsten, platinum, silver, and other metals), alloys (e.g., tungsten-containing alloys, platinum-containing alloys, and other alloys), barium-containing materials (e.g., barium sulfate and other barium-containing materials), and other materials. Wall 15 can also include one or more materials to impart lubricity to catheter 10, such as various fluoropolymer oils, lubricating agents and/or other lubricating additives. Examples include perfluoroethylene, silicone oil, Teflon® flake, Teflon® powder and graphite.
In certain embodiments, the concentrations of additives can vary along the length of catheter 10 (e.g., additive concentrations can vary in a direction parallel to axis 12). For example, concentrations of radiopaque materials can vary to indicate specific locations along a catheter body. The marked locations can then be identified in x-ray images of the catheter as it is inserted or withdrawn from a body site. The markings can be used to ensure reproducible and accurate positioning of catheter 10 with respect to body sites.
Septum 18 can be formed from any of the materials discussed above in connection with wall 15, or from mixtures thereof. Additionally or alternatively, septum 18 can be formed of other materials, such as, for example, natural latex rubber and thermoplastic vulcinates (TPV). In certain embodiments, septum 18 can be formed from the same material used to form wall 15 (e.g., septum 18 can be integral with wall 15). In other embodiments, septum 18 can be formed from a material that is different from the material of wall 15. For example, in certain embodiments, septum 18 can be formed from a material that is more elastic than the material that forms wall 15.
In general, the shape of septum 18 can be selected as desired to provide a particular cross-sectional shape of lumens 24 and 26 within catheter 10. For example, in the embodiment shown in
During use, fluids can be directed to flow through lumens 24 and 26 of catheter 10. Fluids can include gases (e.g., nitrogen, oxygen, nitrous oxide, carbon dioxide, and other gases) and liquids (e.g., water). Fluids can also include solutions of one or more materials dissolved in one or more solvents (e.g., barium ions dissolved in water). The flow rate in a particular lumen varies according to the cross-sectional area of the lumen. Lumens with larger cross-sectional areas can support higher fluid flow rates than lumens with smaller cross-sectional areas.
The cross-sectional areas of lumens 24 and 26 can be changed by displacing septum 18 from its equilibrium position in
The amount by which septum 18 is displaced by fluid pressure and the shape of the displaced septum depend in part upon the septum material. For example, in some embodiments, septum 18 can be formed from a flexible but relatively inelastic material.
In certain embodiments, septum 18 can be formed from a material that is both flexible and elastic, e.g., a material that deforms and stretches under the influence of applied fluid pressure.
When the fluid pressure in lumen 24 is reduced, elastic forces within septum 18 pull the septum material away from inner surface 14 in lumen 26, thereby preventing sticking of septum 18 to inner surface 14 and ensuring that blockage of lumen 26 due to septum adhesion does not occur.
The increase in cross-sectional area of lumen 24 in
In certain embodiments, septum 18 can be attached to inner wall 14 at points that are not symmetrically opposed. For example,
In the embodiment shown in
In some embodiments, one or more anti-adhesion coatings can be applied to inner surfaces of catheters to reduce or prevent adhesion of septum 18 to inner surface 14 of wall 15.
Anti-adhesion coating 40 can be formed from a variety of materials. For example, anti-adhesion coating 40 can include Teflon®-based materials, other fluoropolymer-based materials, and other anti-adhesive materials. Examples of anti-adhesive materials include silicone, parylene, MediGlide™ and BioSlide™. In certain embodiments, coating 40 can include more than one material and/or multiple layers of different materials.
The thickness tc of anti-adhesion coating 40 can generally vary as desired. For example, in some embodiments, tc can be 0.003 inch or more (e.g., 0.004 inch or more, 0.005 inch or more, 0.007 inch or more, 0.01 inch or more). In certain embodiments, tc can be 0.05 inch or smaller (e.g., 0.02 inch or smaller, 0.01 inch or smaller, 0.005 inch or smaller, 0.001 inch or smaller).
In some embodiments, wall 15 can include protrusions configured to reduce or prevent adhesion of septum 18 to inner surface 14 of wall 15.
The maximum length h of protrusions 50 can generally be selected as desired to control a maximum displacement of septum 18, and therefore to control the cross-sectional shapes of lumens 24 and 26 when septum 18 is displaced. For example, in some embodiments, h can be 0.003 inch or more (e.g., 0.004 inch or more, 0.005 inch or more, 0.007 inch or more, 0.01 inch or more). In certain embodiments, h can be 0.05 inch or smaller (e.g., 0.02 inch or smaller, 0.01 inch or smaller, 0.005 inch or smaller, 0.001 inch or smaller). In certain embodiments, the maximum length h of protrusions 50 is less than the thickness tw of wall 15. In some embodiments, a ratio of h/tw is at least 0.05:1 (e.g., at least 0.1:1, at least 0.2:1, at least 0.3:1, at least 0.4:1, at least 0.5:1). In certain embodiments, h/tw is at most 0.95:1 (e.g., at most 0.9:1, at most 0.8:1, at most 0.7:1, at most 0.6:1, at most 0.5:1).
The maximum width w of protrusions 50 can generally be selected as desired to control the surface area of contact between the protrusions and septum 18. In some embodiments, w can be 0.001 inch or more (e.g., 0.002 inch or more, 0.003 inch or more, 0.005 inch or more, 0.007 inch or more). In certain embodiments, w can be 0.05 inch or less (e.g., 0.03 inch or less, 0.01 inch or less, 0.009 inch or less, 0.008 inch or less). In certain embodiments, the ratio of w to h can be at least 0.1:1 (e.g., at least 0.5:1, at least 1:1), and/or at most 10:1 (e.g., at most 5:1, at most 1:1).
The spacing p between protrusions 50 is selected to control the total surface area of contact between the protrusions and septum 18. A larger spacing p corresponds to a smaller number of protrusions 50 in catheter 500, and a greater likelihood (due to the smaller protrusion density) that septum 18 will contact a portion of inner surface 14 of wall 15. A smaller spacing p corresponds to a larger number of protrusions 50 in catheter 500, and a lesser likelihood (due to the larger protrusion density) that septum 18 will contact a portion of inner surface 14 of wall 15. In general, spacing p can be selected as desired. In some embodiments, p can be 0.005 inch or more (e.g., 0.006 inch or more, 0.007 inch or more, 0.008 inch or more, 0.01 inch or more, 0.03 inch or more, 0.05 inch or more). In certain embodiments, p can be 0.1 inch or less (e.g., 0.09 inch or less, 0.08 inch or less, 0.07 inch or less, 0.05 inch or less).
Generally, the number of protrusions 50 can also be selected as desired. For example, in some embodiments, there can be one or more (e.g., two or more, three or more, four or more, five or more) protrusions 50, and or 20 or less (e.g., 15 or less, 10 or less) or protrusions 50.
When fluid flows in a lumen of catheter 500, septum 18 is displaced from its equilibrium position, as discussed previously. If septum 18 is formed from a material that is flexible and elastic, fluid pressure can displace septum 18 so that, in the absence of protrusions 50, septum 18 would contact a portion of inner surface 14 of wall 15. However, as shown in
The cross-sectional shapes of protrusions 50 can generally be selected as desired to prevent adhesion of septum 18 to inner wall 14. A variety of different shapes are possible, including arc segments, half-round shapes. rectangular shapes, triangular shapes, trapezoidal shapes, and other shapes. In certain embodiments, cross-sectional shapes with an undercut (e.g., a 270° arc segment) are advantageous because septum 18 does not generally adhere to undercut portions of a protrusion. As a result, undercut cross-sectional shapes may reduce even further a surface area of contact between septum 18 and protrusions 50. An example of a catheter 600 with protrusions 50 having undercut regions is shown in
In some embodiments, catheters can include fewer protrusions than catheter 500 in
The length h of protrusion 50 is generally less than half the length s of septum 18, and can be selected as desired. The width w of protrusion 50 is generally selected according to a desired stiffness for protrusion 50. That is, w is chosen to be larger to provide a protrusion 50 that is stiffer and less compliant with respect to deformation under an applied load, and w is chosen to be smaller to provide a protrusion 50 that is less stiff and more compliant with respect to deformation.
In the embodiment shown in
In certain embodiments, protrusions can be oriented at an angle to the radial direction of the catheter (e.g., at an angle to a direction perpendicular to axis 12).
In general, catheter 800 can include more than two protrusions (e.g., three or more protrusions, four or more protrusions, five or more protrusions, ten or more protrusions). The protrusions can be symmetrically positioned along inner surface 14 of wall 15, or they can be asymmetrically positioned. Protrusions can further be oriented along radial directions of catheter 800 or along non-radial directions, as desired. The dimensions of protrusions (e.g., maximum length h and maximum width w) and the cross-sectional shapes of protrusions in catheter 800 can all be the same, or some of the protrusions can have different dimensions and/or cross-sectional shapes.
When fluid flows in lumen 24, as shown in
In some embodiments, protrusions can be attached to the septum of a catheter.
Fluid can also flow in either or both of lumens 26 and 28. In certain embodiments, lumens 26 and 28 are coupled to the same fluid source. In other embodiments, lumens 26 and 28 are coupled to different fluid sources. As shown in
In general, multiple protrusions attached to septum 18 can be provided in catheters. In some embodiments, a mixture of elastic and inelastic protrusions can be provided. In other embodiments, all of the protrusions can be either elastic or inelastic. By attaching the protrusions to septum 18, multiple lumens can be formed in a catheter (e.g., two or more lumens, three or more lumens, four or more lumens, five or more lumens, six or more lumens, ten or more lumens).
In certain embodiments, catheters can include one or more recesses extending radially outward from an inner surface of the catheter wall.
Recesses 70 reduce the surface area of contact between septum 18 and inner surface 14 of wall 15. As shown in
The dimensions of recesses 70 can generally be selected as desired to reduce the surface area of contact between septum 18 and inner surface 14 of wall 15. In some embodiments, the spacing v can be 0.005 inch or more (e.g., 0.006 inch or more, 0.007 inch or more, 0.008 inch or more, 0.01 inch or more, 0.03 inch or more, 0.05 inch or more). In certain embodiments, the spacing v can be 0.1 inch or less (e.g., 0.09 inch or less, 0.08 inch or less, 0.07 inch or less, 0.05 inch or less).
In some embodiments, the maximum width m of recesses 70 can be 0.001 inch or more (e.g., 0.002 inch or more, 0.003 inch or more, 0.005 inch or more, 0.007 inch or more). In certain embodiments, the maximum width m of recesses 70 can be 0.05 inch or less (e.g., 0.03 inch or less, 0.01 inch or less, 0.009 inch or less, 0.008 inch or less).
The maximum depth n of recesses 70 can generally be selected as desired. For example, in some embodiments, n can be 0.003 inch or more (e.g., 0.004 inch or more, 0.005 inch or more, 0.007 inch or more, 0.01 inch or more). In certain embodiments, n can be 0.05 inch or smaller (e.g., 0.02 inch or smaller, 0.01 inch or smaller, 0.005 inch or smaller, 0.001 inch or smaller). Typically, the maximum depth n of recesses 70 is less than the thickness tw of wall 15. In some embodiments, a ratio of n/tw is at least 0.05:1 (e.g., at least 0.1:1, at least 0.2:1, at least 0.3:1, at least 0.4:1, at least 0.5:1). In certain embodiments, n/tw is at most 0.95:1 (e.g., at most 0.9:1, at most 0.8:1, at most 0.7:1, at most 0.6:1, at most 0.5:1).
The cross-sectional shapes of recesses 70 can generally be selected as desired to reduce the surface area of contact between septum 18 and inner surface 14 of wall 15. In catheter 1000, as shown in
In some embodiments, catheters can include an outer layer of material to restrict expansion of the catheter.
Coating 80 can be formed from a variety of known materials. Optionally, coating 80 can be formed via a coextrusion process.
Catheters positioned at body sites (e.g., within body lumens) can become occluded during use due to precipitates and other debris carried by fluids flowing therein. In some embodiments, an occlusion in one lumen of a multiple-lumen catheter can be reduced in size or cleared by manipulating the other lumens in the catheter.
The lumens in a multiple-lumen catheter can generally be attached to separate outlet tubes in a hub. Various types of hubs can be used to securely connect a catheter and outlet tubes. A portion of one such hub is shown in
Outlet tubes 96 each have a longitudinal axis 13. The outlet tubes are positioned relative to catheter 10 in the hub so that axis 13 is oriented at an angle γ with respect to axis 12 of catheter 10. In general, γ can be chosen to control an amount of lateral force applied to septum 18 (e.g., force applied in a direction perpendicular to the surface of septum 18). For example, for large angles γ, a relatively large amount of lateral force is applied to septum 18 by fluids flowing into catheter 10 from outlet tubes 96. For small angles γ, a relatively small amount of lateral force is applied to septum 18 by fluids flowing into catheter 10 from outlet tubes 96. Because lateral force results in displacement of septum 18 from its equilibrium position, the ease with which lumen cross-sectional areas in catheter 10 can be enlarged can be controlled by selecting appropriate angles γ. In the embodiment shown in
In certain embodiments, for example, γ can be 3° or more (e.g., 4° or more, 5° or more, 10° or more, 20° or more). In some embodiments, γ can be 70° or less (e.g., 65° or less, 60° or less, 50° or less).
Different features of medical devices such as catheters have been disclosed above. Embodiments can, in general, include any of the disclosed features, as appropriate, to produce medical devices that achieve particular functional and/or performance criteria.
Many different types of catheters can include multiple internal lumens. For example, the catheters disclosed herein can be ocular shunts, endoscopic catheters, peripherally inserted catheters, dialysis catheters, PTA catheters, angiography catheters, drainage catheters, PTCA catheters, overall venous access devices (e.g., tunneled central catheters, midline catheters, subcutaneous port catheters) and other types of catheters.
Multiple-lumen features can also be provided in various types of stents. For example, coronary stents, aortic stents, peripheral vascular stents, gastrointestinal stents, urinary stents, and neurology stents can include the multiple-lumen features disclosed herein. As an example, urinary stents can become occluded with deposits carried by urinary fluids, and the cross-sectional area of the occlusions can be reduced in multiple-lumen urinary stents using the techniques shown in
Other embodiments are in the claims.