FR2519255A1 - CATHETER WITH SELECTIVELY RIGIDIFIED PORTION - Google Patents

Abstract

CATHETER 10 HAVING A RELATIVELY SOFT BODY 12 IN THE FORM OF A HYDROPHOBIC ELASTOMER AND A 14 END PORTION COATED WITH A WATER-INSOLUBLE HYDROPHILIC POLYMER GRAFT ON THIS PORTION TO MAKE IT RIGID IN THE DRY STATE. IN USE, THE HYDROPHILIC COATING ABSORBES OR ADSORBES WATER WITH SOFTENING RESULTING FROM THE COATING SO AS TO MOLTEN THE END PORTION. THE INVENTION ALSO INDICATES A METHOD FOR FACILITATING THE PLACEMENT OF A CATHETER HAVING A MOMENTALLY RIGIDIFIED END PORTION.

Description

Catheter with a selectively stiffened portion.

  The present invention relates generally to an elastomeric tube used for medical devices and in particular for urethral and venous catheters. Such catheters are normally considered to be indwelling catheters in the sense that they are placed and maintained inside.

  the urethra or a vein for a relatively long time.

  The fact that in use these catheters constitute a body

  stranger, they tend to cause considerable irritation

  ble of the fabrics with which they come into contact.

  The problem of minimizing tissue irritation from an indwelling catheter is complicated by the fact that it is generally preferable to provide a relatively rigid tip for the indwelling part in order to facilitate

  the passage of the catheter through the urethra or the vein On no-

  stera that the relatively rigid tip portion of the indwelling catheter worsens the irritation of the adjacent tissue, i.e.

  from the bladder wall or the inner wall of the vein.

  Thus, the invention aims to provide catheters made so as to have a relatively rigid tip portion to facilitate the placement of the catheter, this relatively rigid tip portion losing in service its rigidity for

  reduce irritation of the adjacent tissue.

  A specific example of a case in which it is desirable

  that various sections of a catheter have characteristics

  what is different is that of a urethral catheter

  in which it is desirable to have a curved tip relative to

  rigidly to facilitate the introduction of the catheter through the urethra, which is curved and tightened in its part

upper tie.

  U.S. Patent No. 3,865,666 states that, from a structural point of view, a catheter, such as a urinary catheter, must be rigid enough to be sure that when it travels there urinary tract for placement in the bladder, the catheter tube does not bend

  not to the point of completely or partially blocking the orifice

  this evacuation and the inflation orifice used to inflate a balloon to retain the end of the catheter inside the bladder Said patent therefore describes a catheter having a relatively rigid end portion, but it then lifts

  a significant problem that this tip portion con-

  serve its rigidity in service, which leads to a risk of ir-

ritation of the bladder wall.

  The catheters considered here are generally formed of

  silicone polymers which, due to the hy-

  silicone drophobes, can then be coated with a hydrophilic coating derived from N-vinyl pyrrolidone (NVP) or

  acrylate or methacrylate monomers.

  U.S. Patent No. 4,055,682 provides a

  catheter having a silicone body portion rendered hy-

  drophile by its contact with N-vinyl pyrroli-

  done and exposing the catheter and NVP to high dose ionizing radiation The hydrophilic polymer layer is so thin that the rigidity of the catheter after deposition of the polymer layer, when it has dried, is practically not

  superior to that of a catheter not coated with the same com-

  position and the same degree of crosslinking.

  U.S. Patents Nos. 3,566,874 and 3,695,921 provide Foley urethral catheters to

  remains, of natural or synthetic rubber, having a

  outer garment of a hydrophilic acrylate or methacrylate polymer grafted onto the rubber to reduce the ir-

  ritation and infection normally accompanying use

  However, it has been found that there are problems in use when practically the entire outer surface of the catheter inside the urethra or vein is coated with a hydrophilic polymer, since, like the indicates the aforementioned Patent No. 3,566,874, the layers

  resulting hydrophiles are rigid after drying.

  In normal use of urethral and venous catheters

  The present invention provides a structure at the end of the catheter which is relatively rigid for placement of the catheter and which, after placement in the body, is made less rigid by way to reduce

irritation of the adjacent tissue.

  The invention proposes to make the portion relatively rigid

  tip of urethral and venous catheters formed of a rubber

  natural or synthetic rubber, for example

  a relatively flexible silicone rubber by the application

  cation, for example by grafting, on this end portion of a hydrophilic coating, as for example it is indicated in the aforementioned Patents, which coating makes the portion

relatively rigid tip.

  The description of US Patent No. 3,695,921 is incorporated herein

  with reference to hydrophilic acrylate coatings and

  methacrylate, which are rigid when dry.

  The specification of US Patent 4,055,682 is here incorporated by reference

  main reference to catheters made rigid by the use of

  tion of a high dose of ionizing radiation, for example a dose to which the portion 36 is subjected, although the

  description of this Patent mainly targets the transplant of

  NVP on a silicone catheter body so that the stiffness of the catheter after coating, and after drying of it, is practically no greater than that of an uncoated catheter of the same composition and of the same degree

of crosslinking.

  The object of the invention is to minimize the irritability

  the tissue adjacent to the catheter tip is obtained

  by the hydrophilic nature of the stiffening coating ab-

  sorbing or adsorbing water and, as a result, becoming less rigid.

  The invention will be better understood on reading the description

  detailed, given below by way of example only, of a preferred embodiment, in conjunction with the attached drawing, in which FIG. 1 is a perspective view of a urethral catheter according to the invention; and Figure 2 is a large-scale section of the portion of

  tip of the catheter taken along line i I-II of Figure 1.

  Referring more specifically to FIGS. 1 and 2 of the drawing, we see an improved conventional Foley urethral catheter 10, made of silicone rubber, placed permanently for a

  constant evacuation The catheter 10 has a tu-

  bulaire 12 ending in a tip marked as a whole

  at 14 The body of catheter 10 has an evacuation passage

  tion, not shown, which connects a funnel 16 to an ori-

  evacuation fice 18 An inflatable retaining bag or balloon surrounds the tube 12 at a place located downstream of the evacuation orifice 18, and it is connected therein in a conventional manner in sealing manner A longitudinal inflation passage, not shown , ends with an inflation orifice 22 which communicates

  inside the balloon 20 with the terminal portion of a val-

  ve or an arm 24 in order to introduce water to inflate the

  balloon 20 and retain the tip 14 of the catheter in the bladder.

  The body portion 12 is made of a relatively flexible elastomer.

  ble, for example a silicone rubber, which is hydrophobic and generally inert with respect to the physiological fluids with which it is in contact To facilitate the passage of the relatively flexible catheter 10 through the urethra, the

  end portion 14 is made relatively rigid by the app-

  plication of a stiffening polymer coating 24 which is applied, in the example shown, from a point 26 at the base of the balloon 20 to the end of the tip portion

  It is essential for the present invention that the coating

  polymer 24 or relatively r 1 gide in a dry state,

  generally insoluble in physiological fluids, hy-

  drophile and relatively flexible when wet with physiological fluids such as urine and blood

  coating 24 may for example comprise a hydrophilic polymer

  it consists of NVP or of an acrylate or methacrylate monomer as indicated in the aforementioned Patents It is understood that hydrophilic polymers of NVP or of acrylate or methacrylate monomers are only indicated as

  example that can be used satisfactorily

  very hydrophilic polymers as long as they stiffen enough

  significantly, in the dry state, the tip portion of the catheter 14 and are capable of softening in use, in a time

  reasonable, by absorption of physiological fluid.

  It will thus be noted that the hydrophilic coating 24 comprises

  means for rendering the tip portion of the catheter 14 relatively

  rigidly to facilitate its placement and that, after

  permanently cemented in the bladder, the tip portion 14 is made relatively flexible to reduce irritation of

the bladder wall.

Claims (3)

Claims.   1 catheter (10) consisting of an elongated body portion (12)   relatively flexible in a hydrophobic polymer, and comprises   both a tip portion (14) for introduction into the body   characterized in that this tip portion has mo-   yen making it relatively rigid when dry and relatively   highly flexible in use when in contact with physiological fluid.   2 catheter according to claim 1, characterized in that these   means have a coating of hydrophilic polymer on the door   tip formed from a hydrophobic polymer.   3 Catheter according to claim 2, characterized in that the hydrophilic polymer is generally insoluble physiological fluid.   4 Catheter according to claim 1, characterized the tip portion is curved.   Catheter according to claim 1, characterized it's a Foley catheter.   6 Catheter according to claim 1, characterized it is a venous catheter.   in that in that in that in that in 7 catheter according to claim 1, characterized in that the means comprise a hydrophilic polymer coating formed of a monomer chosen from the group constituted by N-vinyl   pyrrolidone, acrylates and methacrylates.   8 Process to facilitate placement and retention without   tissue irritation of a hy- and venous catheter   3 relatively flexible drophobe permanently placed, characterized in that a coating is applied, which is relatively rigid   when dry, on at least a portion of the catheter tip   ter and the coating is allowed to become relatively flexible   by capturing the aqueous part of a physiological fluid.