Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1994-04-18
2001-02-27
Stright, Jr., Ronald K. (Department: 3762)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S523000
Reexamination Certificate
active
06193699
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a medical tube for animals, particularly humans. More specifically, the present invention relates to a catheter, an intravenous cannula (hereinafter briefly referred to as cannula), a bougie, and other medical tubes used for the examination, observation, prevention and treatment of diseases, such as conduit tubes for introducing liquids into and out of the body, tubes used for vasodilation and removal of thrombus and embolus, artificial blood vessels, artificial tracheae, and so on.
Medical tubes are, for example, inserted into blood vessels, particularly coronary artery, trachea, oviduct, urinary duct, various organs, and so on for the purpose of injection of liquids, aspiration, or patency of ducts. The catheters recently proposed are equipped with many functions besides the ordinary functions mentioned above, such as an illumination fiber and an image guide for endoscope, and some are even equipped with a flash hole. U.S. Pat. No. 4,846,812 proposes a cannula made of a shape memory polymer.
There are many people who become unpleasant or in some cases, suffer from pain upon insertion of a medical tube into the body, during indwelling thereof in the body and/or upon removal thereof from the body (such unpleasantness and condition of the body are hereinafter generally referred to as “feeling of physical disorder” in the present invention). However, such feeling of physical disorder is considered to be of little significance in conventional medical tubes, and naturally, no measures are taken to avoid the feeling of physical disorder. The cannula disclosed in the above-mentioned US patent ignores this aspect. While said cannula reduces swelling with body fluids by employing a two-layer structure with the inner layer composed of a non-hydrophilic resin, since its constituent material is highly hydrophilic, the cannula cannot prevent swelling on being contacted with blood, etc. after insertion into the body, and has a serious defect in that it increases the feeling of physical disorder. Combined with the restriction on the body which is caused by indwelling of a medical tube in the body, such feeling of physical disorder can give a physical, as well as psychological pain.
In the meantime, the enteral Diet catheter (ED catheter) has been drawing attention in recent years. The ED catheter is indwelled in duodenum via mouth or nose, throat, esophagus, and stomach for the administration of component nutrients, enteral nutrients, and liquid diet. At present, ED catheters made of EVA (ethylene-vinyl acetate copolymer) or silicone are being used. Those made of EVA are stiff and can be inserted easily, but give a strong pain and a strong feeling of physical disorder. On the other hand, those made of silicone are too soft to be easily inserted. Therefore, an ED catheter which can be easily inserted and gives less pain and less feeling of physical disorder during insertion and indwelling is desired.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a medical tube which can be easily inserted into the body and gives less pain and less feeling of physical disorder during indwelling in the body and removal therefrom.
The present inventors have made intensive studies for the purpose of achieving the above object, and found that a medical tube made of an organic polymer having a specific mechanical loss tangent and a specific modulus of transverse elasticity to be mentioned later satisfies the requirements of the object, and that the feeling of physical disorder can be remarkably reduced by selecting water absorption of the tube to be inserted into the body from a specific range.
That is, the medical tube of the present invention is made of an organic polymer having a mechanical loss tangent of at least 0.5 at body temperature, and a modulus of transverse elasticity of 1-1000 MPa at body temperature, and in a preferred embodiment, the water absorption of said organic polymer at body temperature is 5 wt % or less.
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Hayashi Shun-ichi
Kaide Tamotsu
Kondo Satoru
Matsumoto Takashi
Tsujikawa Hajime
Nissho Corporation
Stright Jr. Ronald K.
Varndell & Varndell PLLC
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