Central Line Care and Management

Detection & Management of Complications

The ideal tip position for a CL is in the lower one-third of the superior vena cava (SVC) near the junction of the right atrium. CVCs with ideal tip position will have less risk for thrombotic complications or occlusion.

Mechanical complications of insertion

The more frequent are pneumothorax, haemorrhage from either arterial puncture or vein laceration, pericardial tamponade or puncture–related neurologic or thoracic duct injury. Other mechanical complications include thrombosis, thromboembolism, air embolism, and cardiac arrhythmias.

Occlusion 

CVC occlusions are a common complication (occurring in 14–36% of patients within 1–2 years of placement). The signs and symptoms of catheter occlusion include:

• resistance when flushing
• sluggish flow
• inability to infuse fluids
• frequent occlusion alarm on pump
• infiltration or leaking at the insertion site
• inability to withdraw blood
• sluggish blood return.

The degree of CVC occlusion can be partial, withdrawal, or complete.

CVC occlusions can be classified as mechanical, chemical, or thrombotic. Mechanical and chemical occlusions represent 42% of CVC occlusions. Thrombotic occlusions represent 58% of CL occlusions.

Mechanical occlusions

They are related to internal or external problems with the catheter. External occlusions can be caused by issues such as clamped or kinked tubing. Internal occlusions can be caused by incorrect tip placement, compression of the catheter inside the vein, catheter tips against a vessel wall, reservoir detachment. Chest radiography shows mal-positioned catheters, tip placement, or an implanted reservoir detached from the catheter. Intravenous infusion is stopped if catheter tip malposition if suspected until tip placement is confirmed.

Chemical occlusions

They are related to medication or drug precipitate. They can be caused by mixing incompatible drugs, by the infusion of crystallized medication, such as phenytoin, lipids and parenteral nutrition. Instillation of catheter clearance agents recognized to dissolve precipitate may be indicated to restore catheter patency, although there is no evidence on efficacy and safety of chemical interventions for the management of chemical occlusions in CL (ethanol 70% for lipids, hydrochloric acid for acidic infusions, sodium dioxide or bicarbonate for alkalization).

Thrombotic occlusions

Types of thrombosis:

• Intraluminal (5–25% of catheter occlusions).  It is formed within the lumen of the catheter; can cause partial or complete occlusion. Develops as the result of insufficient flushing, inadequate flow through the lumen or frequent withdrawals of blood. It can also be caused by blood reflux (cough, change in intrathoracic pressure).
• Fibrin Tail.  Fibrin adheres to the end of the catheter; more cells and blood products are deposited onto the tail.  Permits infusion but not withdrawal of fluid from the catheter (functions as a one-way valve).
• Fibrin Sheath. It is formed when fibrin adheres to the external surface of the catheter. Occasionally the sheath causes occlusion when covering the end of the CVC. Fluid can usually be injected, but blood cannot be aspirated.
• Mural. It occurs when fibrin from a vessel injury binds to fibrin covering the catheter surface. Vessel wall injury may be due to the catheter rubbing, a traumatic insertion, poor blood flow. It can progress to complete occlusion.

Thrombus formation may occur within 24 hours of the insertion of a device, resulting in catheter dysfunction due to partial or complete occlusion.

Catheter salvage by restoring patency is the preferred approach to the management of CVC occlusions.

Treatment also involves the instillation of thrombolytic agents into occluded lumens of CVC, by direct instillation when the CVC can be flushed (partial or withdrawal occlusions) and by negative pressure technique for complete occlusions. 

Catheter occlusion unresponsive to thrombolytic or chemical treatments is an indication for removal.

Strategies to prevent CVC occlusion:   Flushing routinely with an appropriate amount of flush solution; minimizing the number of times the CL is accessed. Flush with NS solution in between the administration of incompatible medications or solutions has to be done to prevent occlusions due to precipitation.  Patency assessment should be done with every change of tubing or connector. The use of lock solutions such as heparin after NS flushing is used to maintain patency.  Some studies reported that the use of a thrombolytic catheter locking solution (urokinase or alteplase) resulted in a reduced incidence of both catheter-related thrombosis and infection.

Infection

Local infections

• Exit site infections: They present with local warmth, erythema, and tenderness. Presence of pus or cellulitis at the catheter exit site is also diagnostic. Exit site infections can often be managed without catheter removal; in certain cases, if P. aeruginosa is isolated, catheter removal must be considered.
• Pocket-space infections: present with fluctuance around the hub with signs of inflammation or cellulitis.
• Tunnel infections: it can be recognized by the presence of signs of cellulitis in the subcutaneous tissues along the tunnel tract of CL. They are often associated with bacteremia. Most frequently caused by Gram positive bacteria, can also be caused by Pseudomonas and Mycobacterium species. This is an indication for catheter removal plus treatment with IV antibiotics. The infected tunnel tract may require surgical procedures.
• If a patient develops a local site infection, a swab for bacteriology studies should be taken and antibiotics according to local epidemiology and susceptibility have to be indicated.

Systemic infection

According to international registries, there are approximately 30.000 central line associated bloodstream infections (CLABSI) events per year in USA, with a global mortality rate of 12-25% and a cost of around $70,000 per episode.

Definition: Catheter related bloodstream infections (CRBSI) is a clinical definition, used when diagnosing and treating patients, that requires specific laboratory testing to identify the catheter as the source of the BSI. For surveillance purposes, CDC’s National Healthcare Safety Network (NHSN) uses the term central line associated bloodstream infection (CLABSI).

Laboratory confirmed bloodstream infection (LCBI):  laboratory confirmed bloodstream infection that is not secondary to an infection on another site.     Definitions classify CLABSI in: LCBI 1, LCBI 2, LCBI 3; MBI LCBI 1, 2 or 3 (mucosal barrier injury laboratory confirmed bloodstream infection) as defined by NHSN/CDC.

CLABSI: A LCBI where an eligible BSI organism is identified and an eligible central line is present on the LCBI the day of the event or the day before. Therefore, a CLABSI is a primary BSI in a patient that had a central line within the 48-hour period before the development of the BSI and is not related to an infection at another site. Since some BSIs are secondary to other sources other than the central line, the CLABSI surveillance definition may overestimate the true incidence of CRBSI.

The CL must have been in place > 2 consecutive calendar days following the first access of the central line, in an inpatient location, during the current admission. Eligible for CLABSI events until the day after removal from the body or patient discharge, whichever comes first.

Not all organisms are eligible for defining BSI. Not included for LCBI: Campylobacter spp., C. difficile, Enterohemorrhagic E. coli, Enteropathogenic E. coli, Salmonella spp., Shigella spp., Listeria spp., Yersinia spp., Vibrio spp., Blastomyces, Histoplasma, Coccidioides, Paracoccidioides, Crypto-coccus, Pneumocystis. Organisms detected are classified according to CDC recommendations in commensals or pathogens.

Aetiology: The most frequent pathogens are Gram positive bacteria (coagulase-negative staphylococci, Staphylococcus aureus, enterococci), as they are associated with the use of permanent devices.  Gram negative bacilli (Pseudomonas, Klebsiella, E. coli) follow in frequency in CLABSIs reported to CDC, although in some scenarios continue to be the more frequently isolated organisms.

For all common pathogens causing CLABSIs, antimicrobial resistance is a problem. Although methicillin-resistant Staphylo-coccus aureus (MRSA) continue to be isolated in certain ICUs, the incidence of MRSA CLABSIs has decreased. For gram negative bacilli, antimicrobial resistance to third and fourth generation cephalosporins as well as carbapenems has increased significantly.  Candida spp. are increasingly developing fluconazole resistance.

Pathogenesis: There are four mechanisms for infection of CL: 1) migration of skin organisms from insertion site, most frequently seen in short-term catheters; 2) direct contamination by contaminated hands, fluids or devices; 3) less frequent, hematogenous spread from another focus of infection; and 4) rarely, infusate contamination. 

Other important determinants are the material of which the device is made (some of them enhance the adherence of certain organisms e.g., S. epidermidis and C. albicans) and the production of fibrin around the catheter, especially in silastic catheters. The infecting organism can present intrinsic virulence factors such as the extracellular polymeric substance (EPS).  Polyurethane catheters are less frequently colonized.

The adherence properties of a given microorganism in relationship to host factors and the adherence factors produced by organisms are also important in the pathogenesis of CRBSI (coagulase negative staphylococci, S. aureus, Pseudomonas aeruginosa, and Candida species). The production of biofilm allows adherence and potentiates the pathogenicity by diminishing host defense mechanisms or by making them less susceptible to antimicrobial agents.

Risk factors: From the host (patient): underlying disease (specially cancer patients are predisposed to infection complications), absolute neutrophil count (severe neutropenia is a risk factor for CLABSI), requirement of transfusions and parenteral nutrition, excessive use of intravenous medication (as it is associated with more manipulation of CL), increased days of hospitalization (frequently seen in oncology patients). Factors from the organisms have been described before. Type of CL: semi-implantable catheters have more risk of infection compared to implantable devices. Institutional factors: trained staff, adequate relationship between nurses and patients (1:2-5 according to the type of the unit)) and type of unit (ICU have more risk) also affect the incidence of CLABSI.

Treatment: If the patient has signs and symptoms of a systemic infection (no other source of infection detected) and/or the patient has a rigor when accessing the CL, blood cultures should be taken from CL and a peripheral blood.

Antibiotics are indicated according to protocols, taking into account local epidemiology and patient factors (absolute neutrophil count, HSCT receptor or not, previous CL infections), always covering both Gram positive and negative bacteria.

CL removal

Removal of CL must be decided by the type of organism isolated, the clinical situation of the patient, and the presence of persistent bacteremia.

Most CLABSI caused by coagulase-negative staphylococci and Gram-negative bacilli can be controlled with antibiotic treatment without removal of the catheter.

Criteria for CL removal

1. Severe sepsis
2. Thrombophlebitis, endocarditis
3. Evidence of a local tunnel infection
4. Persistently positive blood cultures
5. Recurrently positive blood cultures with the same pathogen
6. Positive blood cultures for:
   • Candida species
   • Polymicrobial infections
   • Vancomycin-resistant enterococci
   • Atypical mycobacteria (e.g., M. fortuitum, M. chelonae, M. abscessus)
   • Bacillus species (forms biofilm)

Criteria for probable CL removal (consider)

1. Exit site or pocket space infection with Pseudomonas aeruginosa, Stenotrophomonas maltophilia, or atypical mycobacteria.

2. Clinical deterioration with known positive blood cultures

3. Positive blood cultures for:

• S. aureus (especially if recurrent infection)
• Viridans group streptococci

Data collection: CLABSI rates are measured according to international recommendations.

CLABSI rate = number of CLABSI episodes / number of CL days x 1000. Data must be collected daily, at the same time of the day by a trained team. CLABSI episodes should not be reported in frequency events, as it would not be comparable.

Strategies of prevention: The prevention of CLABSI includes the development of CLABSI bundles, that imply education and training activities for the staff; surveillance of CLABSI rate and periodic report; protocols on insertion and management of CL, including antibiotic recommendations and removal indications; evaluation and feedback to the staff when an episode occurs.

Thrombosis 

In addition to causing catheter dysfunction, CVC thrombotic occlusions can lead to catheter-related thrombosis (CRT), referring to a thrombus that has adhered to both the catheter and the vessel wall. CRT is associated with CRBSI.

The signs and symptoms of venous thrombosis are pain and swelling on the chest wall, neck, and jaw on the side of catheter insertion/upper extremity; paresthesia or discoloration of the extremity; and loss of function in the extremity.

The diagnosis of thrombosis is confirmed by a doppler ultrasound that evaluates the size and location of the thrombosis.

Anticoagulant therapy must be indicated.

Oncologic patients because of their underlying disease have an increased risk for thrombosis, added to the presence of an implantable intravascular device which also predisposes to this complication.

If the catheter is to be removed it should be 72 hours after anticoagulants are indicated.

If a patient has a thrombosis but the catheter lumen is still patent, then it can be used for IV therapy. The exception to this would be if the thrombosis is occluding the tip of the catheter.

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