A catheter is a medical instrument designed for the cavities and channels of the human body with the external environment. In fact, this is a tube that is inserted into vessels or cavities. The goals of catheterization can be different - fluid drainage, fluid infusion, therapeutic purpose, construction of a channel for the introduction of surgical instruments.
Types of Catheters
From the point of view of the direct purpose of the catheter, two types can be distinguished - abdominal and vascular. The most striking example of the first type is urethral catheters, which are inserted into the bladder and serve to drain urine. In the event that natural emptying is not possible, the installation of this tool becomes a real salvation for the patient. If the introduction of a catheter through the urethra, due to some circumstances, is not possible, then the tube is inserted percutaneously. In addition to the bladder, catheterization is used to compensate for the dysfunctions of such organs: gall bladder, kidneys, stomach.
Another area of application of a cavity catheter is the treatment of cysts and internal inflammatory processes, accompanied by the release of a large amount of pus. If the cyst reaches a large size, then prior to its removal, a preliminary drainage of fluid is required, which can be done by introducing the end of the hollow tube into it.
A vascular catheter is inserted percutaneously into a vein. There are reasons for catheterization in patients who are shown a course of therapy based on regular intravenous infusions and injections. In this case, repeated damage to the vessel during drug administration can be avoided.
Regardless of the type and reason for use, all catheters require mandatory fixation. The tube is attached to the skin using a medical plaster or suture material. Modern models are initially equipped with special clamps, which greatly facilitates the catheterization process. Additionally, it is necessary to set the position of the tube inside the cavity, most often the instrument has a device that allows you to quickly change shape after entering the hollow organ.
The Pigtail system is most widely used - the tip of a catheter made of polyvinyl material looks very similar to a pig tail, hence the name. This device is placed in a special stylet or conductor during production, and after installation it is released and, twisting, prevents the tube from falling out of the organ. Such a fixation system is recognized as the safest and easiest to implement.
For more rigid fixation, a loop is used, which is tightened, previously placed in the cavity of the catheter by fishing line.
Depending on the scope of use, the following types of catheters are distinguished:
- aspiration - effective cleaning of the nasal and oral cavity in order to restore respiratory function;
- epidural - are introduced into the epidural space in order to implement anesthesia;
- urological - are used in the absence of natural urination or with urinary incontinence;
- umbilical cord - used in neonatology for cord blood transfusion;
- gastric - are introduced into the stomach;
- trocar catheters - designed for rapid drainage of fluid from the pleural cavity.
Despite the fact that many species have a similar structure, it is not recommended that they be interchanged. Such actions can cause complications.
Materials for the manufacture
The first medical catheters were made of durable material - latex, elastomer or silicone rubber. They were inflexible and were intended to be reusable. Gradually, other substances were replaced by silicone. The main advantage of this material is that it does not react with biological fluids. But there are significant drawbacks - it is quite fragile, and in some cases small particles of the tube can remain inside the body, provoking a variety of complications.
Depending on the characteristics of the material used, all modern catheters are divided into soft and hard. The first are made of a special composition of rubber or polyvinyl chloride, can be used both medicinally and for surgical purposes.
The material for the manufacture of rigid catheters is metal. These tools are intended for the implementation of diagnostic measures.
For example, if you need to enter a microcamera into the stomach to visualize the state of its walls and mucous membrane, then the sensor is inserted using a metal tube. Modern catheters made of high-quality polymer material, which is safe and hypoallergenic, can be disposable and reusable.
In the case of percutaneous insertion of a catheter into a cavity or vessel, careful care is required. This will help to avoid external or internal infection. First of all, you need to know that there is a clearly limited time for using one tube, after which it is imperative to replace it.
For example, if the device is used for therapeutic purposes, it is recommended to replace it every 48-72 hours. But, if blood preparations are supplied through a catheter, then this time period is reduced to 24 hours.
The area of skin directly adjacent to the injection site is necessarily treated with an antiseptic and covered with a sterile gauze bandage or medical adhesive plaster that does not impede the movement of air.
Vascular catheters must have a rubber tip or valve cap. When shutting down the invasive system, it is important to close the valve immediately - this will prevent air from entering the circulatory system. The catheter must be installed, fixed and removed by a specialist.