EP1135184A1

EP1135184A1 - Tubus with sealed cuff

Info

Publication number: EP1135184A1
Application number: EP99960903A
Authority: EP
Inventors: F. Waldeck
Original assignee: TRACOE Gesellschaft fur Medizinische Bedarfsgegenstande mbH
Current assignee: TRACOE Gesellschaft fur Medizinische Bedarfsgegenstande mbH
Priority date: 1998-12-02
Filing date: 1999-11-09
Publication date: 2001-09-26
Also published as: CA2353007A1; TW458789B; JP2002531187A; WO2000032262A1; AU1771400A; HUP0104580A2; DE19855521A1

Abstract

The present invention relates to a tubus (1) for intubating into the trachea of a patient. Said tubus (1) comprises a central lumen (4) for ventilation or respiration and at least one inflatable cuff (2) which is provided at the outer side of the tubus (1). Said cuff (1) is used for sealing the outer side of the tubus against the wall of the trachea. The outer surface of said cuff (2) is provided with a coating (6) which is more or less free-flowing and/or can swell. The problem of the insufficient sealing is thereby resolved. The cuff (2) is not very sensitive. There is no need for particularly high swelling pressures.

Description

Tube with sealed cuff

The present invention relates to a tube for insertion into a patient's trachea, with a central lumen for respiration or breathing and with at least one inflatable sleeve provided on the outside of the tube, which serves to seal the outside of the tube against the wall of the trachea.

Such a tube can be a tracheotomy tube, which is inserted through a tracheal incision, or an endotracheal tube, which is used through the mouth or nose to ventilate an anesthetized patient or in a coma.

Such tubes are used very frequently in intensive care medicine. A particular problem, especially in the case of prolonged ventilation with the help of an appropriate tube, is the development of pneumonia, which occurs comparatively frequently in intensively cared-for patients and apparently has some connection with this type of ventilation.

When using a corresponding tube, this is, as already mentioned, inserted into the trachea of a patient and positioned so that the area of the tube which is equipped on the outside with the inflatable cuff is in the area of the trachea and generally immediately located below the larynx. The cuff is then inflated via a separate hose or a line integrated into the wall of the tube, the pressure in the cuff being able to be a few tens of millibars. As a result, the cuff swells and lies with its outer wall against the inner surface of the trachea. However, this hinders the regular transport of secretions along the wall of the trachea (from bottom to top) and the secretion may also be strongly stimulated by the foreign body. The secretions that form and accumulate, for example, above the cuff in the area around the tube are very good breeding grounds for the most diverse types of bacteria and other pathogens under the prevailing conditions of temperature and humidity. One might think that a lung infection is nevertheless prevented because the cuff lies close to the wall of the trachea and thus prevents the secretion, which is highly enriched with pathogens and accumulates on the outward-facing end of the cuff, from entering the deep bronchi can penetrate, but it has been found that pneumonia still occurs again and again, which is to a large extent attributable to the use of such a tube. In particular, studies seem to prove that, despite their flexibility and mobility and despite being inflated to relatively high pressures, which can be a few tens of millibars, the cuffs do not yet lie tightly against the wall of the trachea and / or tend to wrinkle, these folds form a channel for secretions and pathogens, which can then lead to serious infections of the lungs.

It has already been proposed to use particularly thin-walled and / or particularly elastic sleeves to avoid such wrinkling, but these sleeves have the problem that they are relatively sensitive and can be damaged very easily, in which case they completely fulfill their sealing and holding function to lose.

Alternatively, one could also try to increase the pressure in these cuffs, but this could lead to an excessive load on the trachea, the surface cells (mucous membrane) of which can be destroyed by the high pressure to which they would then be exposed, possibly even deeper necrosis including the cricoid cartilage can arise.

Compared to this prior art, the present invention has for its object to provide a tube with a corresponding inflatable cuff, which eliminates the problem of inadequate sealing and yet is neither particularly sensitive nor requires particularly high inflation pressures.

This object is achieved in that the sleeve has a coating on its outer surface which is swellable and / or has limited flowability.

If such a coating is caused to swell after the cuff has been inflated or inflated in a patient's trachea, any leaks that may still be present are closed by the swelling material. In particular, the coating material, which may be in any folds and the like, swells, so that these folds no longer form channels through which anything else can pass the cuff. Even if the coating is not necessarily swellable, but at least has a limited flow, a similar effect can be achieved, namely the coating material at mechanically stressed points, for example along the crease lines or the outer surfaces pressed against one another in the area of folds or the like is displaced and distributed to other, non-binding areas. Wrinkles are filled with the coating material, so that the formation of any transport channels in the longitudinal direction of these sleeves can be prevented. It goes without saying that the coating material must have a sufficiently good adhesion to the material of the cuff, in order not to be displaced from the sealing surface into the end face regions of the cuff by the small pressure differences that can occur in the trachea between the two ends of the cuffs be so that the sealing function could be lost.

For the same reason, the material should not be too free-flowing and could, for example, have the consistency of a gel or cream, possibly even a very viscous oil, when in use. A viscosity of the material at body temperature (37 ° C.) of at least 10 Pas (Pascal second), preferably of more than 40 Pas, is preferred.

The coating material can also more or less form a unit with the material of the cuff, for example by partially diffusing the coating material into the wall of the cuff or by inducing it to diffuse or by forming a chemical bond with the material of the cuff. Furthermore, thin binding layers can also be applied to the sleeve material in a targeted manner, which in turn adhere well to the sleeve material, but at the same time also offer a good adhesive base for the sealing coating. The transition from the elastic material of the sleeve to the coating material, which is as tear-resistant and practically non-flowable as possible, can therefore be more or less fluid, which improves the adhesion properties of the coating material to the sleeve material. The coating material can also be one in which neither swelling takes place during normal storage at room temperature nor is there any appreciable flowability (in the range between 1 and 10 Pas). The swellability or flowability can be triggered, for example, by moisture and heat, in particular by the moisture and temperature conditions that are present inside the trachea, but also by reagents, by catalysts, by radiation with X-rays, UV radiation, light or ultrasound or by other mechanical treatment. Otherwise, reagents, catalysts and radiation or mechanical treatments of the aforementioned type can also be used to achieve a good bond between the coating and the base material of the membrane.

An embodiment of the invention is particularly preferred in which the coating material is swellable with water, the swollen coating material also being able to flow to a limited extent. The wall of the cuff itself is preferably made of a polymer and, if possible, is relatively thin, i.e. the thickness of the wall should preferably be no more than 500 μm, better still no more than 200 μm and particularly preferably no more than 30 μm.

Very diverse substances can be considered as coating materials, in particular mucilages and slime formers or gel formers, as well as foaming agents. In detail can these are non-ionogenic mucilages, such as, for example, Salep Mannan, guaran, carobin, starch from wheat, maize, etc., xanthan gum, chitosan, collagen, carmellose, hypromellose, macrogoie, etc. Carrant gum, karaya gum, pectins, alginic acid, carragen, agar, agarose, in particular rehydrable agarose gels, type B gelatin and carboxymethyl cellulose. Cation-active mucilages (gelatin type A) can also be used for the coating. Also suitable are mucilages from drugs, such as Radix Althaeae, Semen Lini, Semen Psylli, Semen Foenugreci, Semen Isphaghulae, seed husks from Plantago Ovata, inorganic gel formers and water-swellable gels from gel formers of synthetic origin, their modification products and combinations of all of the above substances. Furthermore, polymethacrylic acid and its salts, polyacrylic acid and its salts, polydimethylsiloxanes and mixtures thereof in combination with glycerol, waxes, fats or petroleum jelly, and emulsifiers. Another important group of coating compositions which are suitable for the present invention are polyethylene glycols.

Furthermore, the coatings can be made from auxiliaries such as association colloids (amphiphilic, non-ionogenic, anionic or cationic in nature) and / or solubilizers (ionic or non-ionic in nature). It is also possible to provide a plurality of coatings on top of one another which, on their own, may not yet have the desired sealing property, but which mix or react with one another when the double layer is subjected to mechanical stress and thereby form a layer which has the desired properties.

In principle, all water-swellable gels, natural or synthetic substances, polymers or combinations thereof can be used. Thixotropic substances are also particularly suitable, i.e. Materials that change their flow behavior under load, i.e. are easier to flow at higher loads and when shear forces occur than at lower loads. The foaming agents already mentioned can also improve the property of the sealing layer.

With regard to these foaming agents mentioned above, it should also be noted that small bubbles which form in a corresponding layer between the cuff and the wall of the trachea significantly impede any liquid transport. This is related to the relatively large capillary forces or surface tensions that occur on the surface of foam bubbles, so that liquid secretions are bound by appropriate foam bubbles due to these adhesive forces and prevent further flow of secretions.

Also particularly suitable for the coatings according to the invention are polymeric foams and, in particular, those foams which, if possible, consist of the same or a very similar base material as the wall of the membrane itself on the other hand, as already mentioned, the foam layer effectively prevents any Chen secretion flow between the outer wall of the membrane and the wall of the trachea, as well as in the channels formed in folds of the membrane. Open-pore foams or foam layers are particularly suitable. The foam layers also have the advantageous property that they are very highly compressible and in that they are well suited to fill the cavities forming in folds, while the foam is strongly compressed and compressed in some fold areas, it can be used in areas with larger cross sections, which are typically arise at the bottom of corresponding folds, remain extended and thus completely fill the resulting cavity.

As an alternative to the water-swellable gels, it is also possible to use hydrophobic, spreadable preparation forms with a sufficient viscosity, for example hydrocarbon gels, such as lipogels or silicone gels, as are known as solution, suspension, emulsion or suspension emulsion lipogels. Stearate ointments or creams are also suitable as coatings. It is useful if the coating is relatively firm and not very flowable at room temperature, but melts or softens at body temperature.

If possible, the cuffs should be wrinkle-free when they are inflated and nestle against the wall of the windpipe, with thin-walled cuffs being an advantage. The pressures applied should be well below 1 bar.

Polymer materials that have a glass transition point at a temperature above 30 ° C. are also suitable as coating materials.

In a further preferred embodiment of the invention it is provided that the cuff consists of an elastic material and is dimensioned such that it lies practically without folds and relatively close to the outer wall of the tube when not inflated, while in an inflated state under a Inflation pressure between 20 and 30 millibars has a diameter - to be measured perpendicular to the axis of the tube - which is at least 50% larger than the outside diameter of the tube or the previous diameter of the cuff in the non-inflated state, this diameter also in the inflated state can be 100% larger.

By using an appropriately elastic material, which even at a relatively low inflation pressure of a few tens of millibars, the cuff radius is increased by 50% or more, you can ensure that the cuff is free of wrinkles in the inflated state, since the cuff is already in the non-inflated state is essentially wrinkle-free. This also avoids the occurrence of the channels described above, particularly along folds, along which secretions can possibly penetrate from the area above the cuff into the area below the cuff. This execution Form could therefore be used under certain circumstances without an additional coating agent on the outer surface of the cuff and yet seal tightly.

In combination with cuffs made of polymer material, coatings made of water-swellable gels from gel formers with non-covalent linkage of the polymer chains (in the manner of homopolar half-valence gels, secondary valence gels or substances cross-linked by Coulomb forces, etc.) have proven to be very suitable.

Coatings made from water-free, spreadable preparation forms, but which can absorb water in order to swell and which consist, for example, of natural or synthetic substances or polymers and / or combinations thereof, have also proven to be very suitable. Another group of suitable coatings consists of hydrophobic, spreadable preparation forms with a viscosity of 2 Pas and more (for example hydrocarbon gels such as lipogels or silicone gels in the form of solution, suspension, emulsion or suspension emulsion lipogels and stearate ointments or creams).

In general, most of the coatings in question can be classified into at least one of the following groups, although the properties in question should of course also be permanently retained in the trachea.

a) The viscosity of the coating (in the state in the trachea and under the prevailing temperature and / or humidity conditions) is at least 2 Pas, better still at least 10 Pas, z. B. 40 Pas or more. b) the coating material has a relatively large adhesive force on the material of the sleeve, this adhesive force being so great, for example, that a pressure difference of, for example, 30 millibars at the ends of a sealing gap, for example 200 μm wide, does not cause the layer material to flow out leads to the gap, c) the material is highly swellable (at least a 5-fold increase in volume), d) the material is applied in a foam layer (with a minimum thickness of, for example, 200 μ) and it is tens of times at low surface pressures millibars compressible by at least a factor of 3.

Further advantages, features and possible uses of the present invention will become clear from the following description of a preferred embodiment and the associated figures. Show it:

FIG. 1 shows schematically a tube according to the invention with an inflated cuff, Figure 2 is a sectional view looking in the direction of the axis of the tube and with a

Section plane, which runs approximately along the dash-dotted line designated in FIG. 1 and

Figure 3 shows an enlarged section corresponding to the circle labeled III in Figure

Second

1 shows an endotracheal or tracheotomy tube 1, which essentially consists of a tube or a tube 1, on the outer circumference of which an inflatable cuff 2 is provided in a central section. The cuff 2 can optionally be firmly welded to the hose or tube 1, but it can also be glued or made in one piece with the tube 1. A provided in the wall of the tube 1, here not recognizable channel has in the outer wall of the tube 1 an opening in the area of the cuff 2, so that the cuff 2 inflatable via this outlet opening of the channel provided in the wall of the tube 1, but possibly also is ventable. Breathing or ventilation takes place through the central lumen 4 of the tube 1.

Figures 1 to 3 show the subject of the invention only very schematically and the formation of folds 3, which can be seen in all three figures, is only shown schematically here and the folds do not of course have to be uniform over the entire longitudinal extent of the cuff to have.

In Figure 2, the tube in the area of the cuff 2 is shown in section. One can see hatched the wall of the tube 1, a central lumen 4, and two channels 5 provided in the wall of the tube 1, which can be used for inflating, deflating or also for supplying or aspirating liquid or secretion, depending on where the lower ends of these channels 5 open, which can open at the upper end of the tube in corresponding suction or flushing devices.

A corresponding channel 5 also opens into the outer wall of the tube 1 in the area of the cuff 2.

In the figures, the inflated cuff, which can rest against the wall of an air pipe in the state shown, is shown with a whole series of longitudinal folds 3. It goes without saying that these folds 3 do not all have to run parallel and that such folds do not necessarily have to extend over the full length of the sleeve 2. Rather, the illustration is only schematic and is intended to show that there are any folds 3 at all and that due to these folds 3 there can also be channels, albeit with a very small cross-section, along which possibly secretions from the area above the cuff 2 into the Area below the cuff 2 can flow, causing pathogens, especially above the cuff can find favorable growth conditions in the secretion, can penetrate into the deeper respiratory tract and can cause pneumonia.

According to the invention, this is prevented by a coating 6 on the outer surface of the sleeve 2, which can only be seen in the enlargement according to FIG. 3. As already mentioned, FIG. 3 shows the area encircled in FIG. 2 in a further enlarged state, the illustration here also being only schematic and in particular the thickness of the coating layer 6 in relation to the thickness of the wall of the sleeve 2 shown only as a line is possibly exaggerated, but on the other hand, corresponding thickness ratios should not be excluded.

In the enlarged area of FIG. 3, two folds 3 can be seen, namely a slightly less deep fold 3 on the left in FIG. 3 and a comparatively deep fold 3 on the right in FIG. 3. A coating 6 is also shown hatched, which for example consists of a water-swellable gel consists.

If the tube 1 is inserted into the trachea of a patient together with the cuff 2, which has not yet been inflated and lies tightly against the tube 1, the layer 6 is still very thin and hardly recognizable, i.e. one would probably only recognize them in the illustration in FIG. 3 as a layer which, together with the wall of the sleeve 2, could only be represented by a slightly larger line width.

In contact with the water-containing secretion in a patient's trachea, this coating material can swell to form a layer 6, which is shown in broken lines in FIG. The individual folds 3 form a cavity or a channel with the cross section of a drop, especially in the vicinity of their base, where the wall material of the sleeve has the greatest curvature. Ie that the two opposite wall sections of the sleeve 2 in the area of such a fold 3 near the bottom of such a fold are not tight and close to each other, which is probably related to the elastic restoring forces that act in the material of the sleeve 2 and lead to the fact that the kink at the bottom of the fold 3 can not be arbitrarily sharp, but has a finite curvature, which leads to this channel formation. If, however, a coating is provided in this area that swells under the influence of moisture or, for example, heat, this swelling coating material 6, which can be plastically deformable or flowable, closes this channel. In addition, of course, the coating material 6 also swells in the areas where the wall sections of the cuff 2 abut against one another with their outer surfaces in the fold area, and possibly push them apart a little there, so that the layer material 6 is continuously formed in all folds and on Any folds that may be forming are sealed. The same goes for Incidentally, also in the gusset area at the transition of the outer, more or less cylindrical circumference of the cuff to one of these folds 3. The swelling layer 6 also expands there and forms a continuous, homogeneous layer which lies between the inner surface of the trachea and the cuff material 2 . A similar effect is also achieved if the layer is spread thinly on the outer surface of the sleeve 2 as a more or less flowable layer in the form of a cream or a gel. Due to the pressure that the adjacent wall sections of a fold 3 exert on the flowable coating material 6, this coating material 6 is partly squeezed out of the fold area, but partly also pressed into the bottom of the fold 3, where otherwise the channels already described above typically form . Corresponding channels are thereby blocked or prevented. The coating material is distributed on the surface between the trachea and cuff wall 2 in accordance with the available space.

Apart from embodiments in which the coating 6 is relatively firm and in particular abrasion-resistant during storage at room temperature and in the dry state, and these layers only obtain the desired flowability and by means of irradiation, moisture, heat, a reagent or also in connection with catalysts Assuming sealing properties, the coatings can also permanently have the gel-like, flowable state and they can then be covered for the purpose of storage and transport, for example with a thin protective film or protective sleeve, which extend over the cuff and possibly also take up the entire tube. Such a sleeve or cover preferably then consists of a material which in any case has no greater adhesiveness or adhesive force in relation to the coating agent than the sleeve material. The latter preferably consists of a polymeric material. If, moreover, the wall material of the sleeve 2 is as thin-walled as possible, it is ensured that the channels which may be present in the form of the folds 3 have a very small cross-section from the outset, so that these small cross-sections can be filled particularly easily and with little coating material.

Claims

Patent claims

1. tube for insertion into the trachea, with a central lumen (4) for ventilation and with at least one inflatable cuff (2) provided on the outside of the tube (1), which seals the tube (1) on its outside serves the wall of the trachea, characterized in that the sleeve has a coating (6) which is provided on its outer surface and which is swellable and / or has limited flowability.

2. Tube according to claim 1, characterized in that the coating (6) has good adhesion to the surface material of the sleeve (2).

3. Tube according to claim 1 or 2, characterized in that the material of the layering (6) is at least partially diffused into the surface of the material of the sleeve or that a continuous transition from the non-flowable and preferably tear-resistant material of the sleeve ( 2) is provided for the coating (6).

4. Tube according to one of claims 1 to 3, characterized in that the cuff has a maximum wall thickness of 500 μ, preferably 200 μ, and particularly preferably 30 μ or less.

5. Tube according to claim 4, characterized in that the sleeve consists of a polymer material.

6. Tube according to one of claims 1 to 5, characterized in that the coated sleeve is covered with a removable protective sleeve or a removable protective film.

7. Tube according to one of claims 1 to 6, characterized in that the coating (6) swells upon contact with water and / or becomes fluid to a limited extent.

8. Tube according to one of claims 1 to 6, characterized in that the coating (6) swells upon contact with an additional reagent to be added or with a catalyst in the trachea and / or becomes fluid to a limited extent.

9. Tube according to one of claims 1 to 8, characterized in that the coating at body temperature (about 36 ° C) has a considerably greater swellability and / or fluidity than at room temperature (20 ° C).

10. Tube according to one of claims 1 to 9, characterized in that the material of the coating enters into a chemical connection with the material of the sleeve (2).

11. Tube according to one of claims 1 to 10, characterized in that the coating consists of a water-swellable gel.

12. Tube according to claim 11, characterized in that the coating contains at least one mucilaginous or slime-forming agent which is selected from the group of non-ionic mucilages (Salep Mannan, Guaran, Carobin, starch from wheat, corn etc., xanthan gum, chitosan, collagen , Carmellose, Hypromellose, Macrogole etc.), the group of anionic slime formers (gum arabic, tragacanth, karaya gum, pectins, alginic acid, carrageen, agar, agarose, especially rehydrable agarose gels, gelatin type B, carboxymethycellulose), the cationic Mucilage gelatin type A, the group of mucilages from drugs (Radix Althaeae, Semen Lini, Semen Psylli, Semen Foenugreci, Semen Isphaghulae, seed pods from Plantago Ovata) and / or the group of inorganic gel formers (silicates, especially colloidal silica such as aerosil , Bentonite, montmorilonite, hectorite, baydelite, elkonite, halloysite, Veegum etc.) is selected.

13. Tube according to one of claims 1 to 12, characterized in that the coating consists of water-swellable gels, which are produced using gel formers of synthetic origin, their modification products and / or combinations thereof, where appropriate crosslinking agents are used to, for example, Po - lyelectrolytes, polycarboxylic acids such as polyacrylic acid and its salts (Carpopol 904), polymethacrylic acid and its salts, polysuifonic acids, polyacrylonitriles etc., polyalcohols (polyvinyl alcohol, polyhydroxyethyl methyl acrylate etc.), polyethylene glycols (MW 200 - 7500), polyvinyl pyrrolidones, polyols such as, for example, polydimethylsiloxanes (siloprene U1, U10, U165), so-called hydrophilic polyurethanes and mixtures thereof in combination with glycerol, waxes, fats or petroleum jelly and emulsifiers.

14. Tube according to one of claims 1 to 13, characterized in that the coating is additionally produced using auxiliaries such as association colloids (ampiphiier, non-ionic, anionic or cationic in nature) and / or solubilizers (ionic or non-ionic in nature) .

15. Tube according to one of claims 1 to 12, characterized in that the coating of the cuff using gel formers with non-covalent linkage of the polymer chains via physical interactions (in the manner of homopolar semi- valence gels, secondary valence gels or substances crosslinked by Coulomb forces (salt formation).

16. Tube according to one of claims 1 to 15, characterized in that the coating contains foaming agents.

17. Tube according to one of claims 1 to 15, characterized in that the coating consists of a polymer foam.

18. Tube according to one of claims 1 to 17, characterized in that the coating has a viscosity of at least 10, preferably about 40 Pascal seconds (40,000 centipoise) or more.

19. Tube according to one of claims 1 to 18, characterized in that the material of the sleeve consists of a polymer which has a glass transition point at a temperature between 20 and 40 ° C.

20. Tube according to one of claims 1 to 19, characterized in that the cuff consists of a sufficiently elastic material and is dimensioned such that it lies in a non-inflated state smooth and wrinkle-free on the outside of the tube and under an inflation pressure of 20 up to 30 mbar without any external restriction has a diameter which is at least 50%, preferably 100% larger than in the non-inflated state.

21. Tube according to claim 20, characterized in that the cuff has an inflation pressure of 20 to 30 mbar without an external limitation a diameter between 25 and 30 mm.