US 4,906,238 AGrant
Exterior Antimigration Refinements for Self-Cleaning Indwelling Therapeutic Articles
Issue Date:1990-03-06
•11 Claims
•3 Drawing Sheets
Abstract
External grooving on a catheter traps microorganisms nurtured by mucus in a patient's body. The grooving also traps contaminating debris, originating outside the body, that migrates into the body along the catheter exterior. Energy, which may be a propagating vibration or electrical energy or a radioactive material, is carried to the groove (or grooves), from a source outside the body. This function is performed by a fiber embedded or held in the catheter, or by a liquid column (e.g., in an annular lumen) in the catheter, or in other ways. The energy disables microorganisms and disintegrates debris trapped at the groove. The groove depth, interface geometry, and in the case of vibrational energy the vibration frequency too, are selected to minimize projection of energy into the patient's tissues. Suction may be applied as through an auxiliary lumen (or, in some drain catheters, intermittently through the primary drain lumen itself), to remove resulting detritus at the grooving. Circumferential grooves may be used to impede migration longitudinally, longitudinal grooves to deter formation of continuous circumferential sheets of contaminants, or spiral grooves to lengthen the migration path along the catheter--or combinations of these forms.
Metadata
Assignee
- Greenfeld; Albert R.
Inventors
- Albert R. Greenfeld
- Jonathan I. Greenfeld
Application Information
Application Number:US 0960683
Filing Date:1987-09-14
Priority Date:1985-10-15
Art Unit:341
Classifications
IPC:
A61M 2500
Field of Search:
60412822;35;43;264;265;266;267;275;27624 A;303.15;328
Patent Drawings (3 sheets)
Description
Brief Description of the Drawings
FIG. 1 is a generally schematic representation of a preferred embodiment of our invention in use. In this embodiment the therapeutic article is a catheter or other tube.
FIG. 2 is a perspective drawing, greatly enlarged but not to scale with respect to the groove depth, of a segment of the catheter portion of the FIG. 1 system. The segment illustrated is one which, in use, is within a patient's body.
FIG. 3 is a longitudinal section of one form of the preferred embodiment of FIGS. 1 and 2, particularly showing the same segment of the catheter as in FIG. 2. This form of the preferred embodiment employs an embedded fiber as part of the conveying means, and an auxiliary lumen for applying suction.
FIG. 4 is a cross section of the FIG. 3 form, taken along the line 4--4 in FIG. 3.
FIG. 5 is a longitudinal section of another form of the preferred embodiment of FIGS. 1 and 2, also showing the same segment of the catheter as in FIG. 2. This form of the preferred embodiment employs a liquid column in an auxiliary lumen as part of the conveying means, and another, separate auxiliary lumen for applying suction.
FIG. 6 is a cross section of the FIG. 5 form, taken along the line 6--6 in FIG. 5.
FIG. 7 is a longitudinal section of another form of the preferred embodiment of FIGS. 1 and 2, also showing the same segment of the catheter as in FIG. 2. This form of the preferred embodiment employs the primary lumen for application of suction.
FIG. 8 is a cross section of the FIG. 7 form, taken along the line 8--8 in FIG. 7.
Detailed Description of the Preferred Embodiments
As shown in FIG. 1, a preferred embodiment of our self-cleaning indwelling therapeutic-article system includes a suitably powered device 21-23 for developing a flow of energy in appropriate form for projecting along the therapeutic article. In the case of electromagnetic vibration, for example, the device 21-23 may include a power supply 21, transmitting electrical power as at 22 to a high-power pulse laser, microwave transmitter or x-ray generator 23.
If a laser is used at 23, its output may be coupled to one or more optical fibers 32/35 for transmission to the locations along the article where energy is to be applied for disabling of bacteria. If radio-frequency or x-ray radiation is used, analogous provision must be made for conveying and constraining the energy along the therapeutic article without injurious leakage to the patient's body tissues.
As will now be clear, the many forms of energy that might be used to disable bacteria are not all equally amenable to such transmission. In fact some individuals who are skilled in the art may judge implementation of the two forms just mentioned to be so difficult or so costly as to be noneconomic for many purposes. Nevertheless, to the extent that they do have practical uses for particular situations, such forms are encompassed within our invention.
Alternatively, in the case of energy in the form of electricity, the device 21-23 may simply be a power supply for transmitting electrical voltage along wire pairs into the therapeutic article. In the case of mechanical vibration, by comparison, the device 21-23 includes an oscillator and amplifier 21, whose output 22 energizes an electromechanical driver 23. The driver may take any of a variety of forms, particularly including but not limited to piezoelectric, electromagnetic and dynamic-capacitive.
The output of such a driver 23 is mechanical vibration in a manifold bar, rod or the like 31. For some embodiments of our invention, this vibration is advantageously coupled to a plurality of individual vibration-conveying elements 32/35.
These conveying elements 32/35 may include a plurality of elements 32 for carrying cleansing (i.e., disabling and disintegrating) vibration to proximal drain or medication-supply orifices. Various such configurations are detailed fully in the above-mentioned patent.
It is to be understood throughout the present description that the vibration source used for vibrationally cleansing the exterior of a catheter, as herein described, may thus be advantageously shared with conveying elements 32 for vibrationally cleansing the proximal orifices. If preferred, however, separate vibration sources may be used.
In some applications, moreover, it may be desired to use a vibration source for cleansing the exterior of a catheter while vibrational cleansing of proximal orifices is omitted. All such possibilities are to be understood as incorporated by reference into the following discussion and illustrations.
For relative simplicity of the following descriptions and appended drawings, provision for application of vibration to proximal orifices has been uniformly omitted. Thus in FIG. 1 the conveying elements 32 for the orifices are shown terminated as at 34.
Of the numerous remaining conveying elements 35 for vibrational cleansing of the outside of the catheter, again for simplicity only a single representative conveying element 36 is shown in FIG. 1 as continuing into the catheter 811. The catheter 811 has an attachment nipple 13, which may be angled as shown to permit lateral attachment of liquid-carrying tubing 15 while vibration is coupled to the catheter with less-abrupt change of direction.
Liquid is transmitted in or out of the catheter 811 through the tubing 15 as suggested by the double-headed arrow 18. An optical suction device 18a, inter alia, may be connected to the tubing 15, for use as discussed later. For simplicity of the drawing, the tubing 15 is drawn as terminated at 16.
Also for convenience in illustration, a length of the tubing 811 has been omitted between the points 12 in FIG. 1. Thus the equipment 21-35 and 13-18 may be at some convenient distance from the body 1 of a patient--and particularly from the exterior surface 2 of the body, and from the distal aperture 3 (such as a urethral meatus) of the duct or incision 4 to be catheterized.
The catheter 811 may continue at some considerable distance into the patient's body 1. In addition, the phenomena that are of particular interest for purposes of this document occur along the shaft of the catheter 811--most generally without regard to distance from the distal aperture 3, although to some extent the more important regions are more distal.
For these reasons the proximal portions of the catheter 811, the patient's body 1, and the duct or incision 4 have all been drawn in FIG. 1 interrupted as at 5.
In FIG. 1 the portions of the catheter 811 that are outside the patient's body 1, as well as the nipple 13 and tubing 15, are shown in section. The catheter outer surface 846, however, is illustrated in elevation, along most of the portion that is shown inside the patient's body 1. The transition between the sectional portions and the exterior-elevational portions is designated as 12a.
The region of particular interest in FIG. 1 is the very irregular but generally annular volume between the exterior surface 846 of the catheter and the interior surface 4 of the duct (as defined above) or incision. It is in this region that mucus is secreted (particularly in the case of mucous-membrane ducts). It is in this region too that contaminating debris tends to migrate inwardly from the unsterile ambient environment.
Formed in the outside surface 846 of the catheter 811, as shown in FIGS. 1 and 2, is a shallow groove or groove network 847-849. This groove 847-849 includes at least one circumferential depression 848 and at least one spiral depression 847. For some applications these depressions may come together in an intersection or intersections 849.
Groove depths and widths will vary with the type of energy source used and when applicable its frequency, and also with different patient-tissue types, the type of bacteria or debris of greatest concern, and other factors. For mechanical vibration, we believe that adequate cleansing can be obtained, without projecting significant energy into surrounding tissues, by employing a groove depth on the order of two millimeters.
This order of magnitude appears in keeping with the results of ultrasound tissue-attenuation measurements reported for a different medical application by Joie P. Jones, in U.S. Pat. No. 3,941,122. In Jones' experiments, a one-degree maximum rise in temperature appeared at a distance of two millimeters from an ultrasound transducer used for dissolving various organic materials.
A sizable plurality of circumferential grooves 848 may be provided. As will be seen, these circumferential grooves 848 trap and interfere positively with colonization and migration of contaminants along the catheter, and should be disposed for optimum overall impact upon the contaminant problem.
Our invention contemplates instrumenting each groove for the disabling energy--electromagnetic or mechanical vibration, electricity, etc. as previously discussed. Furthermore, other costs will be associated with placement of each groove. It is thus desirable to form only enough grooves to achieve the intended benefits.
For example, such grooves may be placed at regular intervals (e.g., one-inch intervals) along the catheter. Alternatively, they may be placed at relatively short intervals in regions (e.g., near the aperture 3) where contaminant propagation is particularly severe, and at relatively long intervals in less-critical regions.
FIG. 2 representatively includes two spiral grooves 847. Such grooves may be maintained in a mutually diametrical relationship, relative to the body of the catheter, or as suggested in the illustration may have a generally arbitrary relationship.
Spiral grooves--also instrumented for vibration--tend to lengthen the migration path for contaminants, and also prevent the formation of a continuous sheath of contaminants entirely encircling the catheter. The spiral grooves also trap and destroy some contaminants.
We have not determined experimentally the relative benefits of spiral and circumferential grooves. For deeper or more abruptly contoured grooves, however, it is possible that spiral patterns may be preferable to circumferential, for minimum patient discomfort.
Longitudinal grooves have some of these beneficial effects of spiral grooves, but as will be apparent do not lengthen the migration path. Though not specifically illustrated, longitudinal grooving is to be taken as shown by implication: a longitudinal groove is in effect a special case of spiral groove, with zero angle of inclination to the catheter axis.
Our invention encompasses provision of suction apertures 844, 845 at intervals along the grooves 847-849. These apertures, and a suction system (see, e.g., FIG. 1) connected to the catheter outside the patient's body, cooperate to remove the products of action of vibration or other disabling and disintegrating energy applied to the grooves 847-849.
Several representative arrangements for applying energy and suction to the grooves 847-849 will now be discussed.
As shown in FIGS. 3 and 4, vibration or other forms of energy may be conveyed from the manifold bar 31 of FIG. 1 to each groove 847a, 848a by a separate fiber 836a, 836a'. Each fiber 836a, 836a' may be embedded within the catheter wall as shown, and terminated at its respective groove 847a, 848a--directed either toward the side wall or toward the bottom wall of the groove. Alternatively for some applications, as mentioned earlier, the fibers may pass adjacent to the groove, without termination there.
Various fiber materials may be used, depending on frequency when applicable, and on form of energy, power level, therapeutic-article size, the kind and size of patient and site, etc. Plastic, metal and quartz are among the candidate materials.
It is believed that the optimum location of the fiber termination or course relative to the groove for each application can be found with moderate trial and error. Such a location may for example be near the "corner" formed by the base and bottom walls.
An important part of implementing our invention is avoiding patient injury due to projection of vibration into the patient's body tissues. The exact geometry chosen for coupling vibration from the fiber to the groove is expected to be of considerable importance for safety. One possible configuration that may be particularly safe, but whose efficacy in disabling bacteria remains to be seen, is a fiber that runs adjacent--and possibly parallel--to the groove, without termination at the groove.
Hence the evaluation of performance for each fiber-groove configuration must include measurements of energy coupling into surrounding tissue. Such measurements should be made in test circumstances reasonably simulating actual operating conditions.
The vibration-conveying provisions of FIGS. 3 and 4 are closely paralleled in FIGS. 7 and 8. In those latter drawings, corresponding or analogous features have been marked with the same reference numerals as used in FIGS. 3 and 4--but with a suffix "c" instead of "a".
In the embodiment of FIGS. 3 and 4, however, a separate suction lumen 881a is provided for drawing off disabled and disintegrated organisms, or disintegrated debris, from the grooves 847-849. In other words, the previously mentioned external suction orifices 844 and 845 of FIG. 2, here represented as 844a and 845a, communicate inside the catheter with a separate suction lumen 881a.
This form of our invention allows uninterrupted continuing operation of the primary lumen 819a for drainage or medicament supply. Such operation may optimize the effectiveness of any self-cleaning mechanisms at the proximal orifices.
On the other hand, as is particularly clear from FIG. 4, this configuration does to some extent limit the range of circumferential positions available for use in forming suction ducts communicating with the grooves. Moreover, a dual-lumen catheter may be somewhat more costly, and for the same external gauge requires greater care (as, for example, application of more disintegrating energy in accordance with our above-mentioned earlier patent) to prevent clogging, than a single-lumen catheter.
All three of these limitations are avoided in the geometry of FIG. 8, which is suitable for use in some drain applications, and in some other applications not requiring sterility within the primary lumen of the catheter. Here suction is applied (as indicated in FIG. 1) to the primary lumen, from time to time, to draw off disabled and disintegrated organisms, or disintegrated debris, from the grooves 847c-849c.
In the embodiment of FIGS. 7 and 8 it may be necessary to strike a careful balance between the size and configuration of the orifices 844c, 845c at the grooves 847c, 848c, and the size and configuration of the proximal orifices (not illustrated) nearer the proximal end of the catheter. This is important to avoid drawing debris into the proximal orifices, in excess of what can pass through those orifices or what can be handled by the disabling- and disintegrating-energy arrangements there.
Another way of conveying energy to the trapping grooves 847b, 848b is illustrated in FIGS. 5 and 6. Here the conveying means includes a separate lumen 832, preferably an annular lumen as shown. Energy is coupled from the manifold 31 (FIG. 1) through a fixture (not illustrated) to a column of liquid within this lumen.
The lumen may advantageously be made relatively narrow, and the exterior wall enclosing it relatively thin, so that the lumen traverses a distinct step at each groove. It is contemplated that the resulting "water hammer" effect, at the interior side of the wall and undersurface of each groove, will couple energy from the liquid column to materials trapped in the groove.
The conveying means shown in FIGS. 5 and 6 may have a particular benefit--use of the same annular or other lumen to supply energy to the trap grooves and the proximal orifices in common. Formation of the suction-bridge ducts 844b, 845b may be difficult or expensive, but may be favorable in comparison with embedding and terminating a large number of plastic, metal or quartz fibers.
The embodiment of FIGS. 5 and 6 may have, as illustrated, a separate suction lumen 881b analogous to the already discussed suction lumen 881a of FIG. 4. If preferred, however, a unitary drainage-and-suction lumen (not illustrated) like that of FIG. 8 may be substituted.
For the various reasons presented at length in the above-mentioned patent, we prefer to use shear-wave vibration at ultrasound or adjacent frequencies; and vibration-conveying means in the form of quartz fibers, for most applications not over one to two millimeters in diameter. Similarly, the timing of patient vibration exposure should be considered carefully and may be monitored in sensitive cases; and feedback and servocontrolled frequency hunting as described in our earlier patent may be included in the system at the trap grooves. Other features of the above-mentioned patent may be included as appropriate, in the system disclosed here.
While for particularity our invention has been illustrated in use with catheters or like tubes, it is to be borne in mind that nonlumenal articles of therapy are also subject to the benefits of the invention.
It will be understood that the foregoing disclosure is intended to be merely exemplary, and not to limit the scope of the invention--which is to be determined by reference to the appended claims.
Claims
We claim:
1. A self-cleaning indwelling therapeutic-article system, for protected use in an extended condition within a patient's body, the article passing between tissues of a duct or incision in the patient's body; said system comprising: a therapeutic article that has a periphery and a length, and that during indwelling use: passes through such duct or incision, includes a part of said length that is inside such patient's body, includes a portion that is closely encircled by such duct or incision tissues, and defines an external surface that is subject to the presence and propagation of undesirable microorganisms, along the portion that is closely encircled by tissues of such duct or incision; a shallow groove defined in the external surface of the article to trap and interfere with migration of contaminants, said groove being defined along at least the portion that is closely encircled by tissues of such duct or incision during such use; wherein the groove comprises: a generally circumferential depression that passes substantially around the article periphery; and a generally spiral depression that passes substantially around and along at least a part of the article length that is inside such patient's body; a source of effective disabling energy; and means for conveying the energy from the source to the contaminant-trapping groove to effectively disable such undesirable microorganisms at the contaminanttrapping groove and deter such propagation along the portion that is closely encircled by tissues of such duct or incision during use.
2. The system of claim 1, wherein: the generally spiral depression intersects the circumferential depression.
3. A self-cleaning catheter system, for use in protracted transfer of substance between a patient's body and a point outside such patient's body, by way of passage between tissues of a duct or incision in the patient's body, and comprising: a catheter that defines an internal lumen for such protracted transfer of substance, and that: during such protracted transfer passes through such duct or incision, includes a portion which during such protracted transfer is closely encircled by such duct or incision tissues, defines an external surface that is subject to the presence and propagation of undesirable microorganisms, during such protracted transfer, along the portion that is closely encircled by tissues of such duct or incision, and also subject to accumulation and passive migration of contaminating debris along that portion; a shallow groove defined in the external surface of the catheter to trap and interfere with migration and propagation of debris and microorganisms, said groove being defined along at least the portion that is closely encircled by tissues of such duct or incision during such protracted transfer and including: a generally circumferential depression that passes substantially around the catheter periphery, and a generally spiral depression that passes substantially around and along at least a part of the catheter length that is within such patient's body; a source, disposed outside such patient's body, of effective disabling and fragmenting energy; and means for conveying the energy from the source to the trapping groove to effectively disable such undesirable microorganisms at the trapping groove and deter such propagation along the portion that is closely encircled by tissues of such duct or incision during such protracted transfer, and to fragment such debris at the groove.
4. The system of claim 3, wherein: the catheter has a long axis; and the generally spiral depression has at least one segment that runs substantially perpendicular to the long axis of the catheter.
5. The system of claim 4, wherein: the generally spiral depression intersects the circumferential depression.
6. The system of claim 4, wherein: the catheter has a long axis; and the generally spiral depression intersects the circumferential depression and has at least one segment that runs substantially perpendicular to the long axis of the catheter.
7. The system of claim 4, further comprising: suction means for drawing off such microorganisms, or such debris or fragmented debris, or combinations of all three, from the groove.
8. The catheter system of claim 3, wherein: the conveying means comprise a fiber embedded or carried within the catheter.
9. The catheter system of claim 3, wherein: the conveying means comprise a fiber embedded or carried within the catheter and having a termination at the groove.
10. The catheter system of claim 3, wherein: the conveying means comprise a fiber embedded or carried within the catheter and running adjacent to the groove.
11. The catheter system of claim 3, wherein: the energy is in the form of a propagating vibration; and the depth and configuration of the groove, in relation to the configuration of the conveying means and in relation to employed frequencies of the vibration, are particularly adapted to deter significant projection of the vibration out from the groove into tissues of the patient's body.