An Overview of Peripherally Inserted Central Catheters

Complications

PICCs have a relatively low complication rate, but there are several potentially serious issues related to their use. See Table 2 for signs and symptoms of complications.

Thrombus Formation

Any device inserted into the vascular system increases the risk of thrombus formation, either in the vessel or in the catheter. The 3 primary causes of thrombus formation in a vessel are known as the Triad of Virchow.^[5,13]

The first cause is alteration of the vein wall by injury, irritation, or disease process. Vein irritation can occur during PICC insertion or when the vessel is too small to accommodate the diameter of the PICC. A PICC that is too large will abrade the intima of the vein into which it has been inserted. Alterations can also occur when a patient with a PICC uses crutches. The crutch presses against the vessel as it passes through the axilla, causing the PICC to damage the endothelium of the vein.

The second cause of thrombosis is stasis, obstruction, or change in blood flow due to the catheter's presence. For this reason, it is important that the vein size permits sufficient blood flow around the PICC.

Third, platelet aggregation due to hypercoagulability also can cause thrombosis.^[8,18] Patients with hypercoagulable disorders who need central venous access may require a daily low dose of warfarin to help prevent thrombus formation.^[10,16]

Two forms of thrombi may occur. An intraluminal thrombus forms inside the catheter and can result in partial or complete occlusion. It often can be dissolved with a small dose of alteplase, a fibrinolytic agent that is instilled for 30-120 minutes and then withdrawn from the catheter.^[19,20,21]

A mural thrombus forms between the catheter and the vein wall, and can also be partial or complete. A mural thrombus that significantly restricts blood flow around the catheter may cause symptoms such as swelling near and distal to the point of occlusion, peripheral collateral venous distention, periorbital edema or tearing of the eye on the affected side, or discomfort of the shoulder or jaw on the affected side.^[21]

Nonthrombotic Occlusions

Fibrin begins to build up on the catheter soon after insertion, sometimes developing into a sheath that may completely encase the catheter. In this case, infusions still may be possible, but the sheath will occlude the distal opening during aspiration and prevent withdrawal of blood from the catheter. This is known as a persistent withdrawal occlusion.

Fibrin also may build up on a catheter without completely enclosing it. In this scenario, a small piece of fibrin hangs off the catheter tip. This is known as a fibrin tail, which also represents a persistent withdrawal occlusion. These can sometimes be resolved with an infusion of low-dose alteplase over 2 to 4 hours, but this is not always successful, and the fibrin tail may develop again.

Medication crystallization and precipitation may occur if the pH of a solution varies too much from the drug's normal stability range. Adding a solution that brings the pH back to the normal range may liquify the drug and dissolve the precipitate. For crystallized medications with a normally high pH, such as phenytoin sodium, sodium bicarbonate can be infused to raise the pH, hopefully causing the medication to revert to its liquid state. With naturally low pH solutions, such as vancomycin, hydrochloric acid can be used to lower the pH and dissolve a precipitate occlusion.

Lipid occlusions also can occur. These are more prevalent with silicone catheters, as lipid emulsion tends to adhere to silicone. Seventy percent ethyl alcohol is used to dissolve lipid occlusions.

Mechanical occlusions also can obstruct flow through a PICC and can lead to other complications. Mechanical occlusions include crimping of the catheter and tip malposition against a vessel wall. Tip malposition against a vessel is more common with distal tip positioning high in the superior vena cava, and is more prevalent with left-sided insertion.^[22,23]

Phlebitis

Mechanical phlebitis is caused by irritation of the venous endothelium by the catheter.^[4] This is more prevalent with PICCs inserted in the antecubital fossa than in the upper arm. Small veins at the point of insertion, as well as catheter movement when bending and straightening the arm, are the main causes of mechanical phlebitis.

Chemical phlebitis seldom occurs with solutions infused via a PICC, as the infusate exits the catheter at a point with adequate hemodilution. However, damage to the catheter body can lead to chemical phlebitis if the infusate leaks through the damaged area and into surrounding tissue. Sometimes, a fibrin sheath develops over the catheter that allows the retrograde flow of the infusate along the catheter. At the end of the sheath, the infusate can leak into the vein and cause chemical irritation. In some cases, the sheath may even force the infusate to leak at the insertion site. When this occurs, complications include both infiltration and chemical phlebitis.

Catheter Malposition

Malposition can occur upon PICC insertion or later, due to changes in intrathoracic pressure or catheter migration. It is essential that the distal tip termination be confirmed by chest x-ray immediately after insertion and prior to device use, as malposition can lead to serious complications. For example, PICC tip positioning in the distal right atrium or in the right ventricle can lead to arrhythmia. PICC positioning proximal to the superior vena cava can lead to phlebitis and thrombus formation. Whether the proximal right atrium or the distal superior vena cava is the best point for tip termination remains a controversial question. However, a growing body of evidence shows that proximal superior vena cava tip termination has a higher incidence of complications, including tip malposition.^{[22,23,24,25]}

Proper catheter securement is essential to help prevent catheter dislodgment or migration. No tape should be placed over the body of the catheter, as adhesives may cause damage to the catheter. Studies have shown that the use of securement devices is safer and more effective than suturing the PICC adjacent to the insertion site. The use of sutures can lead to complications, such as site infection and catheter-related bloodstream infection, and increases the risk of healthcare worker needle stick injuries.^[26] The sterile securement devices available today include a range of designs to fit the variety of PICCs currently marketed.

Catheter Damage

Catheter damage can occur with any PICC, sometimes due to defective products but more often from improper care. It may result from improper securement or from inadvertently applying excessive pressure when flushing the device. Use of a syringe with a barrel smaller than 10cc's causes increased intraluminal pressure, which may result in catheter rupture. Other causes of damage are contact with sharp objects, applying luer-locking devices too tightly and cracking the catheter hub, and entangling the external portion of the catheter in bed linens, patient clothing, or equipment. Once a catheter has been damaged, it is contaminated.

Damaged catheters sometimes can be repaired rather than replaced. However, repair increases the risk of complications. Catheter repair must be done by an experienced, skilled clinician, using only the repair kit provided by the PICC manufacturer.

Catheter repair is a short-term intervention only, and a repaired PICC should not remain in place longer than the recommended time. Some catheter manufacturers have stopped making repair kits, as injudicious and extended use of repaired catheters has raised concerns about manufacturer liability. A damaged catheter sometimes can be replaced with an over-the-wire modified-Seldinger procedure. In some situations, the best decision is to remove the damaged catheter and replace it with a new PICC at a different site.^[6]

Topics in Advanced Practice Nursing eJournal. 2005;5(3) © 2005  Medscape

Cite this: An Overview of Peripherally Inserted Central Catheters - Medscape - Aug 17, 2005.