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    Приветствую Вас, Анонимный пользователь · RSS 25-09-2017, 01:55

    Главная » Статьи » Манипуляции » Сосудистый доступ

    Broviac Catheters, PICC Lines and Other Catheters

    Broviac Catheters, PICC Lines and Other Catheters


    INTRAVENOUS (IV) CATHETER PLACEMENT

    By far the most common way to put fluids, drugs, or blood into the bloodstream is through a peripheral intravenous (IV) catheter. Peripheral IVs are typically the “over-the-needle” type with the thin catheter on the outside of a needle. The needle is slightly longer than the plastic catheter. The needle is placed into the vein on the arm or leg or, occasionally, the scalp after a tourniquet that distends the vein is placed up higher on the arm or leg. As the needle enters the vein, blood comes back into the needle and the plastic catheter is advanced over the needle into the middle of the vein. IV catheters are commonly available in sizes from 24 gauge (very small) up to 14 gauge (very large). IVs are placed in most patients in the hospital and those undergoing all but the most minor of operations. Risks include development of infection at the point where the IV enters the skin or development of a blood clot or loss of the overlying skin. Both of the last two complications are rare. IV catheters typically are effective for a period of a few days to a week.

    PERIPHERALLY INSERTED CENTRAL VENOUS CATHETERS (PICC)

    In order to have an IV in place for a number of weeks, it must be more stable than a standard IV. This may be accomplished with a catheter that is placed through a vein on the upper extremity (or the lower extremity in infants) and advanced into one of the veins near the heart (Figure 1).










    Figure 1: The peripherally inserted central catheter (PICC) shown inserted into a vein in the middle of the arm and extending centrally to the superior vena cava near its junction with the heart.



    PICC lines commonly are available in sizes from 2 French to 7 French (3 French = 1 mm). A special plastic IV catheter, which can be split apart and which is large enough to admit the PICC line itself, is placed into a vein. The PICC line is trimmed to a length that will allow the tip to lie near, but not in the heart. The PICC catheter is then placed through the IV which is already in the vein and advanced until the tip is near the heart. The initial IV is then split apart leaving the PICC line alone remaining in the vein. PICC lines should be cleansed and dressed. They are good at allowing administration of home antibiotics or nutrition by vein (parenteral nutrition) because of the stability of the access combined with safety.


    CENTRAL VENUOUS CATHETERS

    Central venous pressure catheters or “CVPs” are, in general, plastic tubes or catheters that are placed into the large veins in the center of the body (subclavian, internal jugular, femoral vein) using a needle. The vessel is punctured by a thin needle and a wire is inserted through the needle and passed into the vein. Subsequently, the needle is withdrawn. The plastic catheter is then placed over the wire into the vein, and the wire is removed. Occasionally, these plastic catheters can be placed by “cutdown” where an incision is made in the skin and the catheter is placed directly through a hole, or incision, made in the vein. Veins often used for a “cutdown” include the facial, external jugular, cephalic, or saphenous veins (see below). Central venous catheters provide IVs that can be used to administer nutrition and a variety of drugs that should not be given into a peripheral vein on the arm, leg, or scalp. Central venous catheters can also be used to measure the pressure in the right atrium of the heart which gives information about the amount of fluid in the bloodstream and whether a patient needs to be given more fluid. The risks of central catheter placement using a needle include puncture of the lung in less than 1% of cases and bleeding in even less. Infection is the biggest problem and is most often treated with replacement or removal of the catheter. Care must be taken to avoid leaving the outside end of the catheter open to the air: air may enter the bloodstream which can be dangerous. Central catheters provide stable access for use by patients at home and are effective over a period of weeks.

    BROVIAC AND VAXCELL CATHETERS AND INFUSAPORTS

    Broviac catheters are like central venous pressure catheters except that they are made of a soft material called Silastic and have a cuff on them. The catheters are tunneled under the skin and come out away from where the catheter enters the vein (Figure 2).







    Figure 2: The Broviac cuff being placed into the site where it will come out from the skin ( A ). After insertion of the cuff into the skin entry site and with tunneling of the catheter, the Broviac catheter is being readied for insertion into the external jugular vein by cutdown ( B ). The Broviac is laid out as it will sit once placed into the vein



    The cuff is made of a material which scars into the surrounding fat which tends to prevent bacteria from traveling along the catheter into the bloodstream. The tip of the Broviac catheter is placed into the veins near the heart with the intent of being in place for periods of months to years.


    Broviac insertion has now become one of the most common procedures performed by the pediatric surgeon. The catheter can be inserted into the central venous system by “cutdown” (facial, external jugular, cephalic, saphenous veins) or by using a needle technique (See central venous lines above). Broviac catheters are usually available in sizes from 2.7F to 12F and have one to three lumens or individual tubes down the middle of the plastic catheter. When the needle technique is used, a needle is placed into a vein and a wire placed through the needle into the vein. The needle is then removed. A special central line which can be split is placed over the wire into the vein and the wire is removed. The Broviac is then placed through a tunnel in the skin, cut to the right length, and then passed through the special plastic central line which can be split. The central line is then split and removed leaving only the Broviac in the bloodstream. Broviac catheters must be flushed frequently with heparin if they are not being used. Broviacs are wonderful for children and avoid the pain and fright from needles. However, they can be pulled and accidentally removed, especially by young children. Even though the cuff scars to the surrounding fat, the rate of Broviac catheter infection remains relatively high and is highest among those with short gut syndrome and who require frequent use of the Broviac to give nutrition or drugs.

    The Infusaport was developed for those requiring occasional blood draws, or administration of blood products, chemotherapy, or other drugs. The “port” is a metal or plastic device with a diaphragm on the top that is placed in the fat under the skin and is anchored to the underlying muscle (Figure 3).









    Figure 3: An Implanted port, which is placed in a subcutaneous pocket and accessed using an angled Huber needle.



    Figure 4: A double-lumen catheter, which is placed into a central vein and used for hemodialysis, plasmapheresis, or stem cell harvest.

    Silastic tubing attached to the port is placed into a blood vessel and advanced to near the heart in the same fashion as with a Broviac catheter. Thus, there is no device outside, which is better for patient lifestyle and reduces the rate of infection. The port is used by placeing a special needle through the overlying skin: the needle has a hole on the side so that the outlet of the needle is not blocked by the back of the port. The need to have a needlesticks when using the port may be frightening or painful for young children, which may make the Broviac catheter preferred for some patients.


    DIALYSIS CATHETERS

    Thin-walled catheters with two lumens or tubes may be used to provide dialysis for renal failure; for plasmapheresis for treatment of a variety of disorders; or for stem cell harvest (Figure 4).


    The catheters are typically placed into the femoral, subclavian, or internal jugular veins. A Permacath double-lumen catheter with a cuff can be placed in similar fashion to a Broviac catheter to provide a means for performing long-term hemodialysis.


    PULMONARY ARTERIAL CATHETERS

    Most catheters placed into the pulmonary artery have five lumens (tubes running down the inside of the catheter): (1) a port for injection of air into an inflatable balloon at the tip of the catheter; (2) a probe near the tip that allows determination of temperature and cardiac output (the amount of blood being pumped by the heart); (3) a fiberoptic bundle which can measure the amount of oxygen in the pulmonary arterial blood which gives clinicians an idea of how the patient is doing; (4) a port beyond the inflatable balloon that allows measurement of pressure; and (5) one or two additional infusion/pressure monitoring ports usually placed in the right ventricle and/or right atrium.



    Pulmonary arterial catheters are most often placed by means of a subclavian or internal jugular approach. In young children ( < 2 years old) the femoral vein may be the best to use. Once the catheter is in the vein, the balloon is inflated as the catheter is gently advanced through the right atrium, the right ventricle, and into the pulmonary artery (Figure 5). The pressures which are typical for each of those structures allows one to watch as the catheter moves through the right heart and into the pulmonary artery.








    Figure 5: Pulmonary artery catheter placement. Blood pressure waveforms may be used to monitor passage of the catheter through the ( A ) right atrium (RA), ( B ) right ventricle (RV), the ( C ) pulmonary artery (PA), and to (D) a point where the balloon near the end of the catheter is “wedged” in the pulmonary artery (PCW). When the balloon is wedged in the pulmonary artery the pressure measured in the very tip of the catheter reflects the pressure in the left atrium which gives information about the amount of blood available for the left heart to pump. (From Hirschl RB, Heiss K: Cardiopulmonary critical care and shock. In Oldham KT, et al [eds]: Surgery of Infants and Children: Scientific Principles and Practice. Philadelphia, Lippincott-Raven, 1997.)




    Once the catheter is in place, if the balloon is not inflated, the most downstream part of the catheter will be measuring the pressure in the pulmonary artery. If the balloon is inflated to the point where it completely fills the pulmonary artery, the most downstream part of the catheter, which is beyond the balloon, will be measuring the pressure further downstream at the left atrium. This left atrial pressure is important in that it provides information on how much blood is available for the left heart to pump. This information may be critical to the care of the patient with low blood pressure or decreased blood flow from the heart.

    Complications of a pulmonary artery catheter are few but can be life threatening. Treatment of heart arrhythmias is rarely required. Rupture of the pulmonary artery is a rare, but lethal, complication.


    Placement of a Catheter into the Umbilical Vein

    Umbilical vein catheterization is a simple procedure that allows placement of a large catheter into the venous blood vessels near the heart in a newborn. Catheters can usually be placed into the umbilical vein up to 7 days after birth.


    The large umbilical vein lies on the upper part of the umbilical (belly button) cord stump. Over half of the time the catheter placed into the end of this vein passes from the umbilical vein through the ductus venosus, which is a vein passing through the liver, into the inferior vena cava. Once the inferior vena cava is entered, the catheter generally goes upward toward the heart







    Figure 6: Umbilical vein catheterization. The drawing illustrates passage of the catheter from the umbilical vein into the portal vein in the liver and into the inferior vena cava to the right atrium. The tip of the catheter should be in the inferior vena cava, just at the entrance to the right atrium.



    Central Venous Access Sites

    A catheter (plastic tube) may be placed into the veins near the heart by making an incision over a vein (cutdown) and placing a catheter directly into it or by putting a needle into the vein (percuaneous), passing a small wire through the needle into the vein, and then removing the needle and placing a catheter over the wire into the vein. The wire is then removed and the plastic catheter can then be used. Most commonly, the veins which are accessed by cutdown are the external jugular vein, the common facial vein, the cephalic vein, and the saphenous vein near the groin. (Figures 7-10).








    Figure 7: The most important landmark to find the cephalic vein is the groove formed by the fibers of the deltoid muscle and the pectoralis major muscle.



     











    Figure 8: The course of the external jugular vein. It passes under the clavicle and at that point joins the subclavian vein.

    Figure 9: Anatomy of the common facial vein.


    Figure 10: The saphenous vein at the groin illustrating that the saphenous vein, just as it joins the femoral vein, is large and a cannula easily placed.

     

    Percutaneous needle access to the central veins is most commonly performed through the subclavian, internal jugular, or femoral veins (Figures 11-13)











    Figure 11: Subclavian puncture in an older infant. The finger in the substernal notch is an important guide to the proper angle of advancement of the needle.



    Figure 12: The high medial or “between the bellies” approach to percutaneous internal jugular vein puncture. Note that the insertion of the needle is at the apex of the triangle formed by the two muscular heads of the sternomastoid muscle and the clavicle.



    Figure 13: The anatomy of the common femoral vein. The drawing illustrates the needle going into the femoral vein which is next to the femoral artery and the femoral artery pulsations.


     



    Figure 14: Intraosseous infusion into the tibia or femur. The upper part of the tibia is the preferred site. For the tibia, the needle is directed toward the foot to avoid the growth plate at the knee.

     


    Intraosseous Needle Placement

    In the infant and child younger than 2 years of age intravenous vein catheterization may be especially difficult. In such cases, an alternative to intravenous access includes intraosseous needle placement. The long bones of infants and young children contain a lot of blood in the middle. The tibia and the femur are the common places where an intraosseus needle can be placed. The upper part of the tibia (the bone in the front just below the knee) is preferred.


    Infusion of fluid and drugs into the bone marrow (intraosseous infusion) is an effective emergency route when venous access cannot be rapidly established. Any solutions that can be infused intravenously can be administered into the marrow in the middle of the bone. Drugs that are infused into the marrow appear in the heart within 1 minute. Complications of intraosseous cannulation are rare and include fractures, development of infections, and development of increased pressure among the muscles (compartment syndrome) if drugs and fluid are inadvertently infused into the muscles.


    PLACEMENT OF CATHETERS INTO THE ARTERY

    Arterial catheter placement is used for those patients who require frequent evaluation of blood pressure and in those who require more than two or three arterial blood samples per day. The most common artery used in non-neonates is the radial artery, although the posterior tibial artery and the femoral artery can also be used. Most often a catheter (plastic tube) may be placed into the artery by putting a needle, which has a catheter over it, into the artery (Figure 15).








    Figure 15: Insertion of a catheter into the radial artery. The hand is taped securely to an armboard with a roll placed under the wrist ( A ). The radial pulse is palp ated and the needle/catheter guided at approximately a 30-degree angle through the artery ( B ). As the needle/catheter is withdrawn and passes into the artery, blood may be observed to flow into the hub. The needle/catheter is then advanced a second time and the needle removed ( C ), the catheter withdrawn until blood return is observed ( D ), and the catheter advanced down the artery ( E ). (From Hirschl RB, Heiss K: Cardiopulmonary critical care and shock. In Oldham KT, et al [eds]: Surgery of Infants and Children: Scientific Principles and Practice. Philadelphia, Lippincott-Raven, 1997.)

    Sometimes a needle is first placed into the artery, then a small wire is passed through the needle into the artery, and then the needle is removed and a catheter placed over the wire into the artery. The wire is then removed and the plastic catheter in the artery can be used.

    The technique of making an incision over the artery and placing the catheter directly into the artery is most often used when the needle technique is unsuccessful.


    The umbilical (belly button) artery provides an excellent site for putting a catheter into an artery in neonates. Placement of a catheter into the umbilical artery is a rapid, easy method that allows placement of a relatively large catheter into the aorta. Placement is easiest in the first few hours of life and is only possible for about 4 days after birth.


    Complications of arterial catheter placement, including infection, clot formation, and loss of blood flow to the hand or foot, are surprisingly low.









    Figure 16: The anatomy of the radial artery ( A ). Insertion of a catheter into the radial artery by the cutdown technique. A small incision is performed over the area of the radial artery just above the wrist ( B ). The artery is identified and a needle/ catheter is advanced into the center of the artery ( C ). (From Hirschl RB, Heiss K: Cardiopulmonary critical care and shock. In Oldham KT, et al [eds]: Surgery of Infants and Children: Scientific Principles and Practice. Philadelphia, Lippincott-Raven, 1997.)







    Figure 17: Umbilical artery catheterization showing passage of the catheter. Catheters are usually placed high in the aorta at the level of the diaphragm.



    Источник: http://www.eapsa.org/parents/catheter.cfm
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