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Monday, December 13, 2010

Central Venous Catheters


• Patient may have an urgent need for treatment and no access due to:
     • Acute renal failure
     • Peritonitis from Peritoneal Dialysis
     • Uremia from chronic kidney disease with no matured fistula
     • A wait for a scheduled transplant
     • An agreement with a doctor to have a trial dialysis
     • Refusal of fistula surgery
     • Access failure or infection





• All of these events occur often, so it is good that we can access the blood quickly using a percutaneous (through the skin) catheter or a subcutaneous (under the skin) port/catheter device.
• These devices are made for short-term use - days to weeks - but some patients may need them for months or even years
• Unfortunately, patients who use catheters are more likely to develop blood infections that can be fatal.
• Central venous catheters can damage the central blood .vessels as well as the heart.


Types of Catheter and Port/Catheter Devices
• A central venous catheter is a relatively large tube placed into a high-flowing central vein that leads into the heart.
• Because HD removes and returns blood at the same time, the tube has two side-by-side chambers called lumens.
     • The end of the catheter that enters the patient's blood stream is the "tip", it has holes for blood entry and exit.
     • The other end, the "tail" is outside the body with the two lumens apart.
     • Each lumen has an adapter-connector on the end.
     • The connectors attached to the bloodlines through specially-designed needles that are placed at the start of the treatment.
• The exit site, where the catheter comes out through the
skin, is covered by a sterile dressing, especially when the
catheter is not in use.

Short-term Catheters
• For patient who need short dialysis treatments.
     • Acute renal failure
     • Infection
     • Clotted fistula or graft
     • This type of catheter is short in length because it exits the skin directly over the venotomy (the site where the catheter enters the vein)


Tunneled, Cuffed Catheters
• TCC is longer than a short-term catheter because the tail is tunneled under the skin from the venotomy to the exit site, a few centimeters away.
• Most tunneled catheters have a cuff. :
     • The cuff of the catheter is fibrous material about 5 mm wide, wrapped around the catheter.
     • The cuff is placed about 1 cm up the tunnel from the exit site
     • Healing tissue inside the tunnel bonds with the cuff; this keeps the catheter from pulling out and bacteria from migrating up the tunnel and into the bloodstream.
• For this reason, TCCs are safer and are the preferred type
• Another style of TCC is the single lumen catheter
• Two single lumen catheters must be placed to do conventional HD; one to take blood to the dialyzer and the other to return it.
• These catheters are called twin catheters.


Port/Catheter Device
• Is usually a combination of a port and a single lumen catheter
• This catheter has a tip like a percutaneous single needle catheter, but the tail connects to a metal port placed under the skin (see next slide)
• Two port/catheter devices are needed to do HD.
• The shorter catheter is the "pull", or arterial, line; the longer one is the "return", or venous, line
• The blood stream is accessed by placing a needle into the metal port and opening the valve.
• 1 he dialysis needles are treated like extensions of the catheters.
• The heparin is removed and the needles are flushed with saline prior to connection with the lines.
• At the end of the treatment, the procedure is reversed.
• Removing the needles at the end of each treatment closes a valve that seals each port device internally
• Catheter and Port/Catheter Device Sites
• Catheters for HD are always places in veins tliat are able to support the high blood flows needed for dialysis
• The very large veins in the neck and chest that empty into the right atrium of the heart are the most suitable
• The largest of these, the superior vena cava, collects blood from the head and neck veins (internal and external jugular) and from the arms via the subclavian veins,
• The right internal jugular (RU) vein is the very best because:
     • In most people, it is the largest vessel
     • In most people, it is the shortest and straightest distance to the right atrium of the heart
     • It has the lowest rate of stenosis and/or clots, that would prevent return blood flow from a future fistula or graft in the arm
Note: a catheter should not be placed on the same side as a working flatula or graft.
• The left internal jugular (L1J) is the second of choice, but t is longer and has two large curves to navigate.
     • This reduces blood flow
The subclavian veins should not be used for a catheter unless a surgeon has found that no fistula or graft can ever be placed in the ipsilateral (same side) arm or there is a life threatening emergency.
• The femoral veins in the groin can be used for catheter access when:
     • Temporary access is needed for urgent dialysis and the RU cannot be used
     • Long-term catheter access is needed and none of the upper central veins can be used.
• There are other, more exotic catheter placement such as translumbar or transhepatic for patients who no longer have any of the usual placement sites
• The following principles for venous entry are true for all HD catheters, whether percutaneous or cutaneous.
     • The tips of all catheters inserted into the chest wall should be placed well into the right atrium of the heart and the tips of all femoral veins should be well up into the inferior vena cava (1VC).
     • This tip placement assures the best flow into the catheter, for the best dialysis.

Telling an IJ Catheter Apart from a Subclavian
The subclavian vein is, as its name suggest, below the clavicle (collarbone). Because IJ TCC exit sites are often in the same place as the exit site of a short-term or TCC subclavian catheter, there can be confusion over which vein the catheter enters:

• If a TCC is seen and/or felt over the clavicle, it is IJ.
• If the catheter disappears under the clavicle, it is subclavian.


Placement of Catheters and Port/Catheter Devices
• Most catheters are placed in vascular interventional outpatient centers by a radiologist or a nephrologist.
• Vascular, transplant, and general surgeons also place them, often at the same time as they create fistula or graft.
• Most port/catheter devices are placed in hospitals.
• The main advantage of using a vascular interventional suite or operating room is that x-rays can be done during the procedure, to reduce placement problems
• Catheters must be placed with strict aseptic technique.

• All newly placed catheters are tested by saline flushing to assure function and then locked with heparin to prevent clotting.
• Local anesthetics and conscious sedation - IV medications to relieve pain and sedate the patient - are
used during catheter placements.
• Uncomplicated catheter placements take less than 30 minutes.
• Port/catheter device placement takes longer and is more complex.


IJ Placement
• The IJ vein is 2-3 cm above the clavicle.
• It is found by an ultrasound device, then punctured with a large needle.
• Dark, venous blood is pulled back to prove that the vein was reached.
• A guide wire is inserted through the needle, the needle is removed, and the catheter is advanced into the vessel over the wire.
• Once the catheter is in the vein, the guidewire is removed
• The tunnel under the skin for the TCC placement may be formed first, depending on the type of catheter used.
• The tunnel is usually brought over the clavicle, with the exit site 2-3-cm below'
• Stitches are placed around the catheter at the exit sites of both temporary and tunnel-cuffed catheters.
• The stitches can be removed from a TC after 10-14 days, but should not be removed from a short-term catheters until the catheter itself is removed.
• Placement of any chest catheter can cause:
     • Bleeding ,
     • Hematoma (blood that has collected under the skin)
     • Air embolus
     • Pneumothorax
     • Hemothorax


Subclavian Placement
• As stressed before, the subclavian vein - the large vein in the shoulder that drains the majority of blood from the arm on the same side - should be the catheter site of last resort.
• It is much more likely than an IJ to become stenosed.
• If it must be used, general placement technique and procedure is the same as for an IJ catheter.


Subclavian Placement
• The doctor must take care to prevent kinking of the catheter due to the sharp angle needed to enter the vein under the clavicle.
• The risk of hemothorax and hemothorax may be higher due to the need to puncture directly over the lungs.

Femoral Placement
• The femora] vein is next to the femoral artery in the groin.
• The method for finding the vessel and placing femoral catheters is similar to IV placement.
• The most frequent complication of femoral placement is femoral artery puncture and hematoma.


Port/Catheter Device Placement
• The port is inserted through the incision into a pocket that is formed under the skin.
• After the catheter's placement and tunneling, it is connected securely to the vein.
• Prior to closing with sutures, all pocket bleeding must be stopped.
• The pocket may be flushed with an antibiotic to prevent infection.



Pros and Cons of Catheters and Port/Catheter Devices

Pros

• Patients can have vascular access for urgent treatment.
• Catheters and port/catheter devices can be hidden under most clothing.
• The patient's hands and arms can move freely during dialysis.
• Patients can shower or swim with port/catheter devices, once the incision is healed and the stitches are removed.
• Patients will say that "no needles" is the main advantage of catheters. This must be weighed against the proven higher risk of death and severe illness from long-term catheter use.

Cons
• Catheters and port/catheter devices are more likely to cause life-threatening bacteremias (blood infections).
• Catheters are foreign bodies in the bloodstream and can cause inflammation and clotting in the blood vessels, leading to stenosis and occlusion (blockages).
• Catheters generally have lower blood flows over time, for less adequate dialysis and more frequent procedures. Port/catheter devices usually have more reliably high flows over time.


Care of Catheters and Port/Catheter Devices

Preventing Infection
• The following steps will help prevent infections in catheters and port/catheter devices:
     • Always make sure you have washed yom hands and changed your gloves prior to touching the patient and his/her equipment.
     • Always make sure you and the patient each wear a mask covering both the mouth and nose whenever the catheter is opened or the exit site exposed Airborne bacteria that can infect catheters - and therefore the patient's blood - can be found in mouths and noses of both patients and staff.
• Assess the catheter exit site or port site before staring treatment. Look for any signs of redness, or drainage or pus.
• Always use aseptic technique when opening, handling, cleaning, or cannulating the port, or connecting and dressing the catheter (as per center protocol).
• Teach patients how to protect the catheter and its dressing. Most dialysis center change the dressing at each treatment, and patients shouldn't need to do this between treatments. If the dressing gets wet, it is best to remove the wet dressing, dry carefully around the catheter exit site, and cover the site with a large elastic bandage. To prevent the dressing from getting wet, most centers suggest no showers or swimming for patients with catheters.
• Patients must also be taught not to use sharp objects such as pins or scissors around their catheter. Pin holes put the patient at risk for infection and also require catheter changing before the next treatment. Accidentally cutting the catheter can cause severe blood loss or air entry. The patient should be shown to pinch off the catheter securely and seek medical help immediately.
• Report any problems with the catheter to the nursing staff as soon as possible.

Preparing to Use a Catheter
Predialysis assessment
• Ask the patient about any problems with the catheter during previous treatments or at home.
• Remove the dressing and note any changes in catheter position, such as the cuff becoming visible at the exit site.
• Observe for any redness and drainage (fluid or material coming out around the catheter) such as pus.
• Assess the ease of heparin removal and saline flushing before connecting the bloodlines. Presence of clots and/or sluggish saline flushing suggest that the catheter is blocked or compressed, or that catheter position has changed. This must be corrected before connecting the bloodlines. The nursing staff will further assess the problem and may instill a thrombolytic enzyme to dissolve the clot.


Consideration for accessing catheters and cleansing exit sites
• Prepare procedure site using dialysis precautions.
• Conduct procedures using aseptic technique (correct handwashing, masks for patient and staff, "no-touch" technique, and disposable clean gloves).
• Chlorhexidine 2% with 70% alcohol is the preferred solution for cleansing of central venous catheter sites. (check catheter manufacturer's warnings about the effect of disinfectants on catheter material).
• For patients who are sensitive to chlorhexidine aqueous, povidone solution may be used (use according to manufacturer's directions).
• Skin cleansing should include the following steps:
     1. Apply solution/swab in a circular motion working from catheter exit site outwards.
     2. Cover an area 10 cm in diameter.
     3 Perform this step twice. Do not rinse off or blot excess
solution from skin.
     4. Allow solution to dry completely before applying dressings
• To cleanse the connection between any CVC catheter hub and cap use two swabs;
     1. Hold up the catheter at the connection site with one swab
     2. Use second swab to clean from catheter connection up catheter for 10cm.
     3. Cleanse hub connection site and cap vigorously with the first swab. Discard swab.
     4. Do not drop a connection site once it is cleaned

• To cleanse the section of the catheter that lie next to the skin, gently swab the top and underside of the catheter starting at the exit site and working outwards.
• Always be sure the clamps are closed before opening the catheter to air when pulling off the catheter caps, removing a syringe, or undoing the Luer-Lok® connectors in the lines.


Monitoring Catheters During the Treatments
If pressure alarms signal that the flow cannot be maintained at the prescribed rate, you must:
1. Look at the patient and the lines to make sure there is no major bleeding or air entry. Call immediately for help if there is.
2. Next, assess for mechanical obstruction. Are the lines kinked
anywhere along the circuit? Check again that the catheter is in place.
3. Reposition the patient - lower the head of the chair, have the patient turn his head, cough, etc., to help move the tip of the catheter for better How.
4. Flush with saline to help further assess the condition of the catheter.
5. "Switch" or reverse the lines so that blood is pulled through the "venous" port and returned through the "arterial" port. This should be done to complete a treatment only with the permission of the charge nurse. Line reversing creates recirculation of the blood, which leads to less adequate dialysis - and does not correct the problem. It is also another chance for infection, and all the precautions taken to start dialysis must be repeated.
6. Ask the nurse to assess the problem. He/She may give a thrombolytic enzyme to clear the catheter of a clot.

• If these measures do not restore the prescribed blood flow, the patient should be referred to the interventional doctors or surgeons to correct the problem. This may require a new catheter placement.
• Monitor blood flow through the dialyzer, noting the amount of arterial and venous pressure exerted on the catheter to achieve the prescribed blood How. Always keep the pre-pump arterial monitor connected and open. It tells you the condition of the arterial catheter lumen, as does the venous pressure monitor for the .returning lumen.

Improving Vascular Access Outcomes

Continuous Quality Improvement (CQI)

• CQI can be a powerful tool to help reduce the rate of vascular access problems and provide the best outcomes.
• Collecting data and forming a CQI team are the first steps toward making a plan,
• For example, it might be helpful to begin a log or computer database to track vascular access problems. The log could include:
     • Access type
     • Date of placement
     • Surgeon
     • Continuous Quality Improvement (CQI)
• Type of complication
     • Action taken
     • Data from monitoring tests
     • Clinical assessments
     • Dialysis adequacy measurements
     • Rates of hospitalization, etc.
• By charting this information on bar graphs pattern, patterns can be seen.
• Based on a pattern, your team can devise a plan to solve a problem or improve the practice or process.


Improving Vascular Access Outcomes


Clinical Practice Guidelines
• The KDOQI Clinical Practice Guidelines for Vascular Access give ways to check and preserve a patient's access.
• You can help protect patients' accesses when you use good technique to put in needles, help patients put the right pressure on needle sites after a treatment, and report problems to a nurse or doctor right away.


Conclusion
• Vascular access is one of the most important and
challenging parts of dialysis.
• As a dialysis staff, you have a vital role in caring for your patients' vascular accesses.
• It is your job to learn how to correctly cannulate AVFs and grafts and to assess access sites for problems.
• At all times, remember that each patient's vascular access is a lifeline and must be treated with a great degree of care.


Continuious Quality Improvements / CQI Process


1. Identify Improvement Needs• Collect data
• Analyze data
• Identify problem statement » Prioritize activities

2. Analyze the Process
• Select a team
• Review the data
• Study the process/problem
• Identify partners/trends

 3. Identify Root Causes• Identify probable root causes
• Define/refine the problem





Central Venous Catheters - Related Hemodialysis Article



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