Catheters

Catheters (from Greek kathiemi - I lower), instruments of tubular form, made of metal, glass, ebonite, soft rubber, silk and other fabric impregnated with lacquer. They are used for introduction into the natural passages and cavities of the human body: a) with the aim of emptying retained contents or for washing with indifferent or medicinal liquids; b) for obtaining secretions for examination in the diagnosis of disease. Catheters find their greatest application in urology and surgery for the urethra, bladder, and in recent years also for the ureters and renal pelves. As indicated, they are made from very diverse materials, with glass ones, due to their fragility, usually being used only in women, where due to the shortness and straightness of the canal the danger of breakage is negligible, and glass due to its purity and good sterilizability is a very suitable material. Catheters vary in shape and thickness, measured, as with bougies, by numbers on scales: 1) French (Charriere's) - 30 sizes; No. 30 has a diameter of 10 mm, each subsequent one is 1/8 mm smaller; 2) German (Beinike's) - 60 sizes; No. 60 has a diameter of 10 mm, each subsequent one is 1/3 mm smaller; 3) English - 16 sizes; No. 16 in diameter is 9 mm, each subsequent one is 1/12 mm smaller. The English scale is least used. For determining the number, scales, gauges - metal plates with a series of holes of corresponding diameter marked with their numbers (Fig. 1) are used. The smallest hole through which a given instrument still passes determines its number according to the corresponding scale. Metal catheters (mostly neusilber ones, sometimes silver) are used very frequently. Their advantage is durability and longevity during storage and the possibility of quickly and reliably sterilizing without damage by boiling; but when introduced into a patient they require more skill and experience than soft instruments. The most commonly used are sizes 16-20 with curvature (Fig. 2). Thinner sizes and catheters with a short curved tip (Mercier curvature) (Fig. 3) are less convenient, as they are usually more difficult to introduce and more likely to traumatize the posterior urethra. However, their shape allows good examination of the bladder for the presence of stones simultaneously with its emptying. Female catheters (Fig. 4) are shorter and have a shorter curvature of the tip. If necessary, a woman can easily be catheterized with any male catheter. Among other, less commonly used (for cases where ordinary catheters for some reason do not pass) male metal catheters, mention should be made of Gross's instrument (Gross; Fig. 5), with an end made of dense flat metal wire, which makes the end of the catheter resiliently flexible; Brodie's catheter (Brodie; Fig. 6), with a very large curvature in a semicircle for cases of markedly expressed hypertrophy of the prostate; Mosetig's catheter, with a conical end and a screw-on soft thread-like conductor (a conductrice), very convenient in strictures (Fig. 7); catheter a double courant with two separate channels inside for simultaneous injection and outflow of liquid and continuous washing (Fig. 8) of the bladder. Mention should also be made of catheters for washing the urethra - Ultzmann's (Ultzmann; Fig. 9), differing from the previous ones in that it has a series of small holes further from the tip for irrigation of the urethra during the reverse outflow of liquid alongside the catheter. Elastic catheters made of woven fabric are manufactured by French, English and German firms (Porges, Jakes, Ruesch and others). They, while having free flexibility, still have sufficient rigidity to be introduced easily, and moreover with almost no risk of traumatic damage to the canal. They are made straight with an oval or olive-shaped end (Fig. 10) or with an end (tip) curved according to Mercier (Fig. 11) at various angles. These latter instruments are introduced most easily. In hypertrophy of the prostate gland and difficulties in passage, elastic catheters with a short (according to Mercier) tip and not round but elliptical (the long axis of the ellipse in the same plane as the curvature of the tip) cross-section of the catheter itself - the Bartrin model (leech form) - are very good. For the same cases, catheters with a double bend of Guyon (Fig. 12), bicoudé, have been proposed. Elastic, thinner Guyon catheters with a large olive and holes behind the head (Fig. 13) are used for washing and instillations into the posterior urethra. Elastic catheters are introduced into the bladder very conveniently, easily and with less unpleasantness for the patient and therefore are favorite instruments in the West. They are better than rubber ones (Nélaton's) in that their internal lumen is always wider than that of rubber ones, and that when introduced they can be held by the hand far from the tip and not touch the parts being introduced into the posterior urethra and bladder, as they are sufficiently rigid, and this allows the entire operation to be performed under conditions of stricter asepsis. Rubber catheters are softer, and therefore, if the catheter is to be left in the canal for a long time (a demeure), to avoid bedsores on the mucosa preference should be given to them. The disadvantages of elastic catheters for us are their foreign origin, lesser strength, impossibility of frequent and repeated boiling, which rather quickly destroys them, and high price. Better and stronger in relation to boiling are the white catheters of the Porges firm in Paris. For leaving for a long time a demeure, Pezzer's (Pezzer; Fig. 14) and Malecot's catheters from soft rubber with a large thickened head on the bladder end, made of thinner but more elastic rubber, are very good. They are introduced into the bladder stretched over a special metal mandrel, when stretched on which the head is drawn out in length and becomes equal in caliber to the catheter and passes easily. After removal of the mandrel the head takes the shape of a button and does not allow the catheter to fall out of the bladder. Removal is done either by careful stronger pulling or by re-introducing the mandrel. Catheters for the ureters are made of silk elastic fabric and are distinguished by great length - about 40-45 cm and small caliber - No. 5, more often 6-7 and up to 10 (rarely) according to Charriere. In length they are usually marked in centimeters, so that when introduced into the ureter one can see exactly how many cm the instrument has entered into the ureter itself. Their tips are made either olive-shaped (according to Casper) or obliquely cut with a terminal and lateral hole of Guyon (a bee de flute). They are manufactured by the firms Ruesch and Porges. Recently these catheters have been made impregnated with a mass impermeable to X-rays. Such instruments, introduced into the ureter, give on the X-ray film a clearly visible shadow determining the position of the ureter and its relation to shadows suspicious of stones, and thus to a certain degree replace pyelography. In gynecology special metal catheters are used for introduction into the uterine cavity during operations and for irrigation and disinfecting washings (most often after curettage). There are many different models of them. In the USSR the Bozemann model (Bozemann; Fig. 15) is most commonly used. In the treatment of ear diseases, metal catheters are also used, which in form resemble an ordinary female metal catheter (Figs. 16 and 17). They have an opening at the end, usually in the form of a button-like thickening; they serve for blowing the tympanic cavity through the Eustachian tube and are introduced through the lower nasal passage. Through such catheters it was even proposed to introduce bougies into the Eustachian tube (from whalebone or from woven silk fabric like filiform ones for the urethra), but this method did not become widespread.

A. Gagman. Catheter lung - a device proposed by Pfliiger for delimiting a part of the lungs in dogs from communication with the atmosphere and obtaining alveolar air from this part for subsequent determination of CO2 in this part. The device is a rubber tube introduced deep into the bronchus and ending with a rubber balloon. With the help of a syringe attached to the side of the lung catheter, the balloon is inflated and interrupts communication between the cavity of the corresponding part of the lung on the one hand and the cavities of the other bronchi and the trachea on the other. Inside the lung catheters passes an elastic tube of smaller diameter in such a way that its end protrudes somewhat from the balloon of the lung catheter. Through this tube the alveolar air to be investigated is sucked out with the help of a mercury pump. Lit.-see lit. to art. Catheterization.