Vascular access in the treatment of cystic fibrosis.

Introduction

The treatment of cystic fibrosis requires the frequent use of antibiotics. Unfortunately, several antibiotics can only be given intravenously. While intravenous administration is perceived by some as a sign of disease progression, it is in reality the bacteria to be treated that directs the choice of mode of administration. Indeed, the unwanted visitor to the lungs of people with cystic fibrosis, Pseudomonas aeruginosa, reacts to a small number of oral antibiotics but to several intravenous antibiotics. Hence the importance of catheters, which provide reliable vascular access allowing the entire treatment to be administered.

A central venous catheter is a tube, inserted into a peripheral vein (in the arm for example) or into a large vein (such as the jugular or subclavian vein), whose distal end is located at the junction between the superior vena cava and the right atrium.

This type of catheter allows the administration of solutions with high or low pH — which is irritating to the veins — or solutions whose osmolarity could damage the inner lining of the vein. Several antibiotics fall into this category of medications, which are called “irritants.”

There are several types of central venous catheters, but some are better suited to the needs of adults with fibrocystic fibrosis. This article focuses on these different types of vascular access, the risks associated with each, their benefits, and the most common complications.

Types of central venous access

The central percutaneous catheter

is used when central access is urgently needed. It is inserted quickly and allows the administration of a large volume of liquid or even solutions that are very irritating to the veins. In adults with fibrocystic disease, it is usually inserted into the jugular vein because of the high risk of pneumothorax when accessing the subclavian vein. It may remain in place for a few days until the medical condition is stabilized. The most common complication of this type of catheter is an infection that occurs when the catheter is inserted in a place that is heavily colonized by bacteria in the mouth or respiratory tract.

Peripherally inserted central catheter (CCIVP)

Commonly called PICC or PIC line for Peripherally Inserted Central Catheter, is inserted into a vein in the arm (basilica, brachial or cephalic) for a treatment of more than four weeks or more than five days with a drug whose pH or osmolarity may be irritating and damaging to the peripheral veins. It has undoubtedly become the most frequently used central venous access in recent years because it was believed to be safe and relatively simple to insert. Unfortunately, more and more studies are reporting on the complications inherent in this type of vascular access, including catheter-associated thrombosis and catheter infection, the two most severe complications, and catheter occlusion, the most common complication.

The implantable chamber

Which is also called the Port O-Cath®, Infus-a-Port®, POC, PAC, or simply Port... In all cases, the term refers to a catheter that is completely implanted under the skin. To insert an implantable chamber, the surgeon or interventional radiologist accesses the jugular, subclavian, or axillary vein using ultrasound. Depending on the vein chosen, it may or may not include a small tunnel and a pouch in which part of the catheter and the implantable chamber are placed. This type of catheter is ideal for patients who will need intravenous medication over and over again because once inserted, it can be reached in under two minutes with a special needle. It allows patients to swim when not in use and, depending on the preferred room type and installation type, can be more easily disguised. In return, some patients complain that the seat belt is rubbing on the room. Women also report that sometimes the chamber is rubbing on the bra strap or visible in the cleavage — requiring a different bra model or other type of cleavage. To prevent these problems, the patient may suggest a location on the chest where insertion would be less of a problem. Another solution is to perform the insertion into the forearm, when the peripheral veins are quite large or have not been damaged by several previous CCIVPs and there is enough tissue to cover the chamber. More and more doctors are agreeing to do the insertion in a “non-traditional” place.

The mid-long (midline) catheter

It's very similar to a CCIVP, except that on the inside, it's much shorter and ends just before the axillary vein. It may constitute acceptable vascular access if the solution to be administered is not irritating to the veins and if the therapy is to last less than four weeks. Over time, however, the repeated use of this type of device could damage the vein to the point where it would become unusable for a CCIVP or the installation of an implantable chamber in the arm.

Possible complications

Vascular access is not without risks and complications. The most common complications include infection, thrombosis (a clot in a vein), catheter occlusion or blockage, catheter tip migration, and skin reactions. The following section describes these complications and simple interventions to prevent them.

The infection

Connected to the central catheter is a severe complication that can be life-threatening for patients. The highest risk is associated with the percutaneous catheter, followed by the CCIVP and then the mid-length catheter, while the implantable chamber represents the lowest risk. Infection occurs when a microorganism migrates to the bloodstream. Microorganisms can travel to the outer surface of the catheter, from the insertion site, or to the inner surface of the catheter, from the injection cap or the female tip of the catheter, during injection into the catheter or changes in tubes and plugs. When this occurs, contamination can become significant and cause blood infection or bacteremia.

To prevent infection, the following measures have been proven to be effective in the most recent studies:

• hand washing before handling the catheter (changing the dressing and accessing the cap);
• changing the dressing when it is soiled or detached and the catheter is not sufficiently stabilized;
• the disinfection of the cork by means of vigorous friction for at least 15 seconds (this is the time needed to sing Have a nice day twice!) ;
• the use of a needleless stabilization device (no stitches) to stabilize the A study demonstrated the higher risk of infection when using stitches. This is probably due to the fact that the stitches cannot be disinfected effectively when changing the dressing, that they are close to the insertion site, that they offer an additional entry point for bacteria and that they promote inflammation;
• removing the catheter when it is no longer needed (we don't keep the catheter “just in case...”).

Catheter-related thrombosis

Is a severe complication that can cause chronic complications, such as post-thrombotic syndrome or venous stenosis, or other acute complications, such as pulmonary embolism. Catheter-related thrombosis is when the vein is partially or completely obstructed by a clot formed on the catheter. Thrombosis occurs when the following three conditions are met:

1. hypercoagulability — an individual factor that cannot be altered;
2. venous stasis, common when a large part of the blood flow is reduced in a blood vessel;
3. damage to the inner lining (endothelium) of the vein, which occurs during movements of the catheter within the vein or after the catheter passes at the time of insertion.

The risk of thrombosis is higher with CCIVP because this type of catheter is often larger at the insertion site, which blocks blood flow where the vein is smallest, and because the catheter moves when coughing or during irrigation.

However, some measures can reduce the risk of thrombosis:

• do light exercises on the arm in which the CCIVP was inserted in order to increase blood flow into the vein;
• ensure sufficient hydration;
• apply heat to the arm, above the insertion site, for twenty minutes, every four hours, on the day of the insertion and the following day;
• avoid taking blood pressure from the side of the catheter
• If a bandage is placed around the arm to prevent the tubing from being bulky, make sure that it does not reduce blood flow and that it is not too tight.

Catheter occlusion

Eis a common complication that causes a lot of concerns. It is recognized by the impossibility of obtaining venous return during aspiration, when the venous return is hesitant or when it is not possible to irrigate or to perfuse into the catheter. Occlusion occurs when a clot or medication crystals block the inner lumen of the catheter, when a small clot covers the end of the catheter, or when the end of the catheter is on the wall of the vein. In all cases, the occlusion must be treated because it can increase the risk of infection, especially if it is caused by the presence of a clot. To prevent catheter occlusion, a pulsatile irrigation technique (i.e. by creating turbulence by pulsating on the syringe piston during irrigation), an adequate volume of solution (at least 10 ml of saline solution followed or not by a solution composed of heparin) and an adequate closure technique will be used. It is important to validate with the nurse which closure technique to use depending on the type of plug (some plugs require clamping before disconnecting, others after).

Catheter migration

Is described as the displacement of the distal end outside the superior vena cava. It can occur as a result of changes in intrathoracic pressure, for example during a cough or during an effort, but also because the catheter is partially removed from the insertion site. During migration, the end of the catheter can move into the jugular vein or even into the transverse brachiocephalic vein. Improper positioning of the distal end is a very important risk factor for thrombosis. To avoid migration, during insertion, care should be taken to position the distal end at the junction between the vena cava and the right atrium. Sometimes, positioning in the auricle is even necessary to avoid any risk of migration into the jugular vein. As another means of prevention, particular attention will be paid to the outer portion when changing the dressing so that the catheter does not leave the insertion site. If the outer portion changes by several centimeters, the catheter has migrated. Also, in the absence of change in the external portion, the patient could hear, at the time of irrigation, the sound of a river or even a flow from the side of the catheter. If this is the case, the catheter has most likely migrated. A chest x-ray is then required and the catheter should not be used until its location is confirmed. Note that it is normal to “taste” or “smell with your nose” when saline is injected. Indeed, some patients have sensations during central catheter irrigation when pre-filled syringes are used. This side effect is safe and “normal.”

Skin reactions

Erosion Of the skin (only with the implantable chamber)

Occurs when the skin becomes so thin above the implantable chamber that it eventually breaks. This complication is often related to insertion, but some factors may contribute, such as poor nutritional intake and underweight. Also, to prevent it, the needle will be replaced every seven days (when the chamber is in use) and the location of the injection will be varied by moving the skin on top of the chamber while avoiding transplanting into the same site.

Contact dermatitis

Is a skin reaction caused by a bandage, disinfectant, or a combination of both, especially when there is insufficient drying time. To avoid it, take care to let the disinfectant solution dry completely (without blowing or blowing!) before applying the transparent dressing.

Vascular accesses are among the tools necessary for the administration of intravenous treatments. However, they are not without risks. CCIVP may seem appealing because it is completely removed at the end of treatment, but it can also be responsible for significant complications. When the medical condition requires the repeated use of intravenous antibiotics, it is appropriate to discuss the various options with your health care team in order to make the best choice and to avoid unnecessary damage to the vascular network, as this may narrow down options in the long run.

Once the choice is made and the catheter is in place, regardless of which one is in place, great care and caution should be taken to prevent avoidable complications.

France Paquet

Inf. M.Sc. CVAA (C), VA-BC (TM)

Clinical Practice Consultant — Vascular Access and Intravenous Therapy

Transition Support Office - McGill University Health Center

Montreal (Quebec)

Canada

Bibliographical references

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• CHOPRA, V., ANAND, S., HICKNER, A., HICKNER, A., A., BUIST, A., A., A., BUIST, M., M., ROGHER, M.A.M., SAINT, S., FLANDERS, S.A. (2013). “Risk of venous thromboembolism associated with peripherally inserted central catheters: a systematic review and meta-analysis”, The Lancet, May 20, pp. 1-15.

• DAL MOLIN, A. et al. (2012). “Totally implantable central venous access ports in patients with cystic fibrosis: a multicenter prospective cohort study”, Journal of Vascular Access, 13, 3, p. 290-295.
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• O'grady, N.P. et al. (2011). “Guidelines for the prevention of intravascular catheter-related infection”, Center for Disease Control, available at http://www.cdc.gov/hicpac/pdf/guidelines/bsi-guidelines-2011.pdf.
• Yamamoto, A.J., SOLOMON, J.A., J.A., SOULEN, M.C., et al. (2002). “Sutureless securement reduces device complications of peripherally inserted central venous catheters”, Journal of Vascular Interventional Radiology, 13, p. 77-81.

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