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Catheters are one of the most commonly used medical devices nowadays, and they have became indispensable in almost all fields of medicine, as their importance in the medical management of a variety of patients can hardly be denied (von Eiff et al 2005; Trautner & Darouiche 2004; Bestul & VandenBussche 2005). For instance, central venous catheters (CVCs) are important in the treatment of critically ill patients, such as cancer patients, because they facilitate chemotherapy, transfusions, parental nutrition and blood sampling (Verso & Agnelli 2003; Bestul & VandenBussche 2005; Shorr et al 2003; McGee & Gould 2003). CVCs are also important in caring for patients who need repeated venous access, and they are also placed in the patients for invasive hemodynamic monitoring (Veenstra et al 1999; Shorr et al 2003; McGee & Gould 2003; Pearson & Abrutyn 1997). Meanwhile, other forms of catheter (aside from CVCs) include peripheral venous catheters, midline catheters, haemodialysis catheters, pulmonary artery catheters, and peripheral artery catheters for adults while for paediatrics peripheral venous catheters, peripheral arterial catheters, umbilical catheters, and central venous catheters (O’Grady et al 1999).

However, the use of catheters has one downside: the risk of infection. Several studies have concluded that whereas CVCs are indispensable in the treatment of critically and chronically ill patients, they are the leading cause of nosocomial bloodstream infections (Maki 1992, 1989; Rupp & Craig 2004; Haase et al 2005; Yucel et al 2004; Trautner & Darouiche 2004; von Eiff et al 2005; Hanna et al 2003; Raad et al 1997; Mermel 2001; Safdar & Maki 2002; Bong et al 2003; Maki et al 1997), which is a leading cause of morbidity and/or mortality among intensive care unit patients as well as higher health costs (Rupp & Craig 2004; Haase et al 2005; Ahmad 2002; Gidwani 2002; Shorr et al 2003). On the other hand, the use of long-term CVCs in chemotherapy has been associated with the occurrence of upper-limb deep venous thrombosis (UL-DVT) (Verso & Agnelli 2003), whereas patients undergoing hemodialysis are prone to catheter-related bacteremia, which, on the other hand, may cause metastatic complications (Marr et al 1997). Other CVC use complications include mechanical complications and thrombotic complications (McGee & Gould 2003).

Catheter Colonization

Infection is a life-threatening complication, especially in patients who are compromised. Two types of infection may occur: local infections, which may be in forms of exit site, port pocket and tunnel infection; and systemic infections, which may result from a colonized thrombi or fibrin sleeves or extraluminal or intraluminal colonization of the catheter (Wickham et al 1992).

How do catheters become colonized? Accordingly, factors such as the kind of catheter used and its surface properties, the immune competence and the diagnosis of the patient, the protocol of catheter care, the development of thrombosis and the microorganisms’ abilities determine the risk of catheter colonization (Wickham et al 1992; Bestul & VandenBussche 2005). In particular, Bestul & VandenBussche (2005) cited factors such as the catheter’s physical irregularities and charger differences, the presence of proteins (i.e. fibronectin, fibrinogen, fibrin, laminin, thrombospondin, and collagen) that act as adhesions in the patient, and the organism’s hydrophobicity and its ability to form “slime” or a biofilm as determinants of catheter adherence to micro-organisms.

Meanwhile, organisms found in the catheters nowadays are different from ten years ago. What can commonly be found before are gram-negative aerobes like Escherichia coli, Klebsiella and Pseudomonas aeruginosa are common, whereas these days, organisms such as gram-positive aerobes from the skin like Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus species, Candida species, coagulase-negative cocci as well as Pseudomonas, Stenotrophomonas maltophilia, Actinobacter species, gram-positive bacilli like Corynebacterium jeikeium, and Bacillus species have become frequent (Wickham et al 1992; De Cicco 2003).

Organisms normally found in the skin usually migrate to the area of insertion and into the cutaneous catheter tract and colonizes the catheter tip and is a source of infection in peripheral catheter, while contamination of the catheter hub contributes to intraluminal colonization of long-term catheters and occasionally catheters might be hematogenously seeded and become focus of another infection. Intravascular devices can become source of infection or contamination during non-aseptic device insertion or non-aseptic care of every part of the line like the connectors or catheter exit site at the catheter hub (O’Grady et al 1999; De Cicco et al 2003).

Signs and symptoms of catheter-related infections may vary from erythema, pain to fever and localized skin reactions like rash and blister which maybe secondary to transparent dressing, plastic tape cleansing solution or ointment (Wickham et al 1992).

Management of these infections ranges from local site care like change of dressing, antimicrobial ointments, and oral antibiotics to intravenous antibiotics or removal of catheter (Wickham et al 1992).

Indications for removal of catheter in patients with catheter-related infections are bacteremia or showing of clinical symptoms 48-72 hours of intravenous antibiotics therapy, progressive insertion site, exit site or subcutaneous tunnel infections, reproducible chills or hypotension after irrigation of catheter, bacteremia due to Bacillus species or Corynebacterium species and fungemia due to Candida species, unstable patients clinically, evidence of septic embolism or endocarditis, catheter no longer needed or useful (Wickham et al 1992).

Reducing Catheter-Induced Infection

There are available strategies to prevent catheter-related infections in adults as well as pediatric patients. These include site of the catheter insertion, type of catheter material, hand hygiene and aseptic technique, skin antisepsis, catheter site dressing regimens, catheter securement devices, in-line filters, antimicrobial or antiseptic impregnated catheters and cuffs, systemic antibiotic prophylaxis, antibiotic or antiseptic ointment, antibiotic lock prophylaxis, and anticoagulants (O’Grady et al 1999).

For catheter site insertion, O’Grady and colleagues (1999) said it is important to carefully consider the site where the catheter is to be inserted since it can influence and risk infection and phlebitis; site is related to risk of thrombophlebitis and density of local skin flora. In this lieu, the lower extremities in adults are associated with a higher risk of infection than the upper extremities. Likewise hand veins have a lower risk for phlebitis than veins on wrist or upper arm. Density of skin flora is also a big factor for infection that is why it is recommended that central venous catheter be placed in the subclavian area instead of the jugular area or femoral area to reduce the risk of infection. The type of catheter material use also plays a role because Teflon or polyurethane catheters have been associated with lesser infections and complications than with catheters made from polyvinyl chloride or polyethylene. Steel may also be used as it has less infection rate but use of steel on the veins may result in complication like infiltration of intravenous fluids into subcutaneous tissues (O’Grady et al 1999).

Hand hygiene and aseptic technique may offer protection against infection. Hand hygiene can be achieved by use of alcohol or an antibacterial soap and water with adequate rinsing. Aseptic technique can be done by using new pair of gloves for every insertion of catheter. Skin antisepsis may be done by using povidone iodine for cleansing arterial catheter and central venous catheter insertion sites. Other antiseptics used are alcohol 70%, and 2% acqueous chlorhexidine gluconate. Catheter site dressing regimens include transparent, semi-permeable polyurethane dressings reliably secure device and permit continuous visual inspection of catheter site, allows patient to bathe and shower without damaging dressing and require less frequent changes than that of the gauze dressing (O’Grady et al 1999).

Antimicrobial or antiseptic impregnated catheters and cuffs have been used to prevent or lessen the risk for catheter-related bloodstream infection. There are several types of these catheters, like Chlorhexidine-Silver sulfadiazine-Impregnated Catheters, which can be left for 11 days or less with less risk for infection. In vitro studies, it was shown that Pseudomonas stutzeri exposed to Chlorhexidine without Silver Sulfadiazine have developed resistance to Chlorhexidine as well as other antibiotics. For Minocycline-Rifampin-Impregnated Catheters can be placed on the average of 6-7 days. This combination is associated with a much lower risk of infection than the combination of chlorhexidine-silver sulfadiazine-impregnated catheters. The active ingredients are found both intraluminal and extraluminal unlike the chlorhexidine-silver sulfdiazine where it is found extraluminal surface only. No resistance was observed for minocycline-rifampin-impregnated catheters. After the minocycline-rifampin catheters were implanted for 7-14 days then placed on agar plates they noted Staphylococcus aureus growth seen in zone of inhibition. Unfortunately, Staphylococcus epidermidis can grow even if the catheter is impregnated with minocycline-rifampin (O’Grady et al 1999). No protection is offered by the antibiotics coating the catheter.

Catheters modified with miconazole and rifampicin that constantly and slowly release antimicrobial substances are assumed to be beneficial in reducing rates of colonization and catheter-related infections. In fact, a randomized clinical trial found a lower risk for catheter colonization and catheter-related infections among CVCs that are supersaturated with miconazole and rifampicin as compared to standard catheters (Yucel et al 2004). Catheter hubs containing Iodinated alcohol is also available. The catheter hub has an antiseptic chamber filled with 3% iodinated alcohol. This catheter can be placed for 15-16 days. The hub reduces the incidence of infection.

Chlorhexidine-Impregnated sponge dressings used at insertion sites of central venous catheter and arterial catheter (Mermel 2001). Platinum/Silver – ionic metals also have broad antimicrobial activity and are being used in catheters and cuffs to prevent catheter-related bloodstream infection. Silver cuffs have been used in subcutaneous collagen cuffs attached to central venous catheter. The ionic silver can offer antimicrobial activity and the cuff itself can be used as a mechanical barrier to the migration of organisms along the external surface of the catheter (O’Grady et al 1999). The use of antibiotic-impregnated CVCs should be considered for patients with a high risk of catheter-related bloodstream infection (3.3 per 1000 catheter days) despite strict adherence to aseptic technique and barrier precautions. Burn patients and neutropenic patients are examples of high-risk patients (Ahmad 2002).

Non-technologic interventions such as use of maximal barrier precautions like large sterile drape; long-sleeved sterile gown; sterile gloves; sterile mask; sterile that resulted in lower rate of infection compared to those using only minimal precautions like small sterile drape and sterile gloves. Nurses who are trained for peripheral catheter insertions have lower rate of infection than those who are not trained for it (Mermel 2001).

Systemic antibiotic prophylaxis is not demonstrated to have a significant reduction of risk, but among low birth weight infants, vancomycin prophylaxis appeared to have a reduction in infection rate but not mortality rate. Antibiotic or Antiseptic ointments like Povidone-Iodine ointment applied at insertion site for haemodialysis catheters to reduce catheter-related infection and there was a reduction of infection of exit-site infection, catheter-tip colonization and bloodstream infection with routine use of Povidone-Iodine comparing it to the other sites without the ointment. Mupirocin ointment has also been used though it may reduce the risk of infection but there is also a chance for resistance to develop and might affect the integrity of the polyurethane catheters. Mupirocin has develop resistance to Staphylococcus aureus and coagulase-negative Staphylococci after routine use of mupirocin (O’Grady et al 1999)

Catheter-related bloodstream infections (CRBIs) are a cause of significant morbidity and mortality in intensive care unit patients. Development of CRBIs may occur by several mechanisms. The role of fibrin and biofilm development and their impact on therapy are described. Multiple preventative strategies related to the insertion and maintenance of the catheter site had been identified. Using topical antisepsis and antibiotic-impregnated catheters can also reduce the incidence of CRBI (Haase et al 2005). Antibiotic lock prophylaxis has been attempted to prevent catheter-related bloodstream infection by flushing and filling lumen of the catheter with an antibiotic solution and leave the solution inside the catheter lumen. Patients who had vancomycin ciprofloxacin heparin or vancomycin heparin have significantly lowered rate if catheter related bloodstream infection than those whose lumen is filled with heparin alone (O’Grady et al 1999). The concept of Antibiotic lock prophylaxis is to prolong the life of the catheter inside the body and to reduce morbidity and cost of catheter related infections (Bestul et al 2005).

Replacement of catheters should be schedule to prevent phlebitis and catheter-related infections. In certain studies, peripheral venous catheter left in place more than 72 hours increases the bacterial colonization. For midline catheters, they can stay for up to 49 days but if there is a specific indication then catheter should be replaced. Those with haemodialysis catheters infection risk increases sevenfold, so it was suggested that instead of hemodialysis catheters arteriovenous fistulas and grafts are favored. Pulmonary artery catheter is inserted through a Teflon introducer and remains in place for 3 days. Most of the catheters are heparin bonded so it reduces catheter thrombosis and microbial adherence to the catheter. Most pulmonary catheters are packaged with a thin plastic sleeve to prevent contamination and they found out that those patients who used catheters with self-contained sleeves have a lesser risk of infection than those without the sleeve. Peripheral arterial catheters are inserted into the femoral or radial artery to monitor continuously blood pressure and blood gas measurements. If the catheter is placed more than 4 days, there is a risk for an infection which is both local and catheter-related (O’Grady et al 1999).

Management of systemic infection are based on probable causative organism, susceptibility of microbes to antibiotics and the underlying cause of neutropenia. Without any laboratory results such as blood culture, patients can be given broad-spectrum beta lactam and an aminoglycoside. Patients who are febrile and nonneutropenic may be given antistaphylococcal penicillin or vancomycin (Wickham et al 1992).

As was mentioned, complications can occur in the form of mechanical, infectious, and thrombotic complications. Mechanical complications can be arterial puncture, hematoma and pneumothorax during insertion of catheters. Subclavian catheterization is more likely than internal jugular catheterization to be complicated by pneumothorax and hemothorax while internal jugular more likely associated with arterial puncture. Arterial puncture and hematoma are common during femoral venous catheterization. Infectious complications may arise from infection from the exit site, migration of pathogen along the external catheter surface, contamination of the catheter hub leading to intraluminal catheter colonization and hematogenous seeding of the catheter. After a study, subclavian venous catheterization has a lower risk for infection than femoral vein catheterization (McGee et al 2003). Accordingly, to prevent complications from arising, care should be taken from choosing the site to the catheter being used and monitor the site of catheter insertion for signs of swelling or infection; if catheter has served its purpose, it can be taken out to lessen the catheter related infection chances (McGee et al 2003). Further, prophylactic antibiotics may be given to lessen the rate of infection (McGee et al 2003).

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