Central venous catheters (CVC) are frequently used in critical care units, hemodialysis units, and oncology units for the administration of intravenous fluids, medications, blood products, parenteral nutrition, vasoactive medications, hemodialysis, and hemodynamic monitoring. Unfortunately, the presence of indwelling CVCs increases the risk of the formation of thrombi, emboli, and infection than patients with peripheral catheters by 200%.
Central line infections are more common than any other healthcare-related infection and account for 33,000 deaths per year. Additionally, CVC infections are associated with increased morbidity, increased mortality, increased length of stay, increased healthcare costs, increased diagnostic tests, and increased antimicrobial use. The development of central line-associated bloodstream infection (CLABSI) may increase the patients’ length of stay up to three weeks for an average additional healthcare cost of $33,000.
Recommendations have been established and published by the Healthcare Infection Control Practices Advisory Committee (HICPAC) and the Centers for Disease Control and Prevention (CDC) to guide health care professionals in the use of evidence-based practices for central line care.
Anatomy and Physiology
There are three common sites for the insertion of a CVC: the internal jugular vein, subclavian vein, and femoral vein. Each of these has its own advantages and disadvantages. The common features between all sites are that all involve a skin puncture, dilated tract through the skin, subcutaneous and muscle layers, insertion into a proximal peripheral vessel, and a catheter which is fed into the vena cava. This procedure requires knowledge of the surface and ultrasound anatomy of these areas.Infection rates are known to differ between anatomical sites with significantly lower rates of infection in subclavian lines and significantly greater levels of infection in femoral sites.
There are multiple indications for central line placement:
- Drug administration (caustic infusions and other high-risk infusions such as TPN)
- Fluid administration (large rapid volume administration, administration when peripheral venous access is difficult)
- Monitoring (Physiology, central venous pressure, directing fluid resuscitation, central venous oxygen saturation)
Any patient requiring these during their hospital stay will need appropriate care to maintain and use this central access.
The care should encompass a routine of insertion checks, daily monitoring, monitoring as the patient's condition changes, and clinical governance standards to ensure they are used correctly.
The daily care of the CVC insertion site should concentrate on keeping the area dry, clean, and uncontaminated.
There are a number of contraindications to the insertion of a central line. Most of these should be considered by the clinician at the time of insertion, but others can develop during the patient's treatment and period of care.
- Embolic issues
- Existing central venous clots - Clots within the central circulation can be dislodged by CVCs, leading to embolic complications such as stroke.
- Valve vegetations - Bacterial vegetations on valves can be dislodged and lead to infarction or infectious complications.
- Tumors - Myocardial tumors can be friable or provide a prothrombotic surface for clots to form.
- Bleeding risk
- Patients with existing hemorrhagic tendencies related to hematological conditions
- Previous trauma or surgery to the site which increases the risk of arterial puncture
- Pharmacological treatment affecting the patient's clotting.
- Infection at the site of insertion is an absolute contraindication.
- Infectious symptoms may develop at a central cannula site and must be monitored and treated, usually by removal of the catheter.
- Bloodstream infections are a relative contraindication acknowledging that a CVC may become a surface for biofilm formation and bacterial persistence and, therefore, likely to need more frequent changes.
- Skin trauma
- Radiation damage to the insertion site
- Pressure ulceration or damage to the insertion site which can occur from the CVC itself
- Direct trauma
The use of an existing site for the placement of a catheter may preclude the use of that site for further cannulation efforts, although a recent review suggests that the previous concerns around the presence of other central catheters do not mean the ipsilateral vein cannot be used for hemodialysis catheter placement. This suggests current or previous placement is unlikely to represent a contra-indication top placement, especially if the initial placement was not complicated.
Insertion and care should always be performed under sterile conditions with appropriate hand hygiene, draping, and sterile materials.
The start of any procedure where the catheter dressings are exposed should begin with skin cleansing. The majority of catheter-associated infections have been shown to be related to skin colonization. This risk has been shown in a randomized controlled prospective trial to be reduced sixfold by skin cleansing with chlorhexidine solution. Therefore we recommend the use of a 2% chlorhexidine-containing solution or purpose-made applicator.The use of antibacterial preparations on the site after insertion is not routinely recommended. It has been shown to result in lower rates of sepsis-related to CVCs but has also been demonstrated to increase the risk of resistant bacterial infections and Candida colonization and subsequent infection.
Dressings are an essential item to contribute to keeping CVCs and their insertion site clean and dry. The most commonly used dressings comprise an adherent transparent polyurethane film. These have the clear advantage of allowing constant inspection of the site to identify local infection, pressure damage, or other complications visible at the insertion site without the need for a dressing change. However, a large study of 343 patients who were having routine catheter insertion showed a 2.3% rate of infection when dressing with both gauze and an overlying transparent dressing was used. The use of transparent impermeable dressings has been suggested to increase skin colonization and lead to infection because of moisture trapping. A 2006 review concluded that a permeable dressing leads to lower moisture pooling and colonization levels and should be recommended. The access hubs of the CVC are another important potential source of introducing infection, and this possibility must be reduced by careful adherence to cleaning and aseptic non-touch technique (ASNTT) when using the hubs and connecting infusions. A number of advances have been made to try and reduce the incidence of infection via this route, including gauze wrapping containing povidone-iodine and a specialist hub designed by a Spanish research group. Although these have been shown in randomized controlled trials to reduce infection, they have yet to be widely accepted.
Crystalloid fluids are routinely continuously infused into central lines used in the intensive care environment; this allows the lumen to be flushed regularly and is necessary to provide pressure above a transducer to measure central venous pressure. Central venous pressure monitoring is recommended both as a physiological measure but also to allow identification of when the catheter has migrated or been misplaced.
This guidance is relevant for medical and nursing staff in ICU, OR, Renal dialysis units, and chemotherapy units where frequent interactions with CVCs are likely. The settings with a prolonged patient stay or where patients will be treated as outpatients with indwelling catheters for long periods should pay particular attention.
The UK National Institute for Clinical Excellence recommends: "Healthcare workers caring for a patient with a vascular access device should be trained, and assessed as competent, in using and consistently adhering to the infection prevention practices described in this guideline."
It is essential, as mentioned above, to prepare the skin by an appropriate cleansing procedure. The materials chosen for routine care and cleansing discussed above should be assembled, and an appropriate setting such as the ICU or Operating theatre should be used.
Once these preparations have been made, the patient should be appropriately informed and consented if awake, and the dressing change or other care should be performed using ASNTT with minimal delays to avoid leaving the site uncovered.
The care of a central line includes routine inspection and dressing changes. The dressing changes allow a more detailed site inspection and cleansing of the skin/site. How often these changes are done is a matter of contention; there has been a benefit demonstrated by 48 hourly dressing changes with the use of chlorhexidine washes at every change compared to similar care at 7-day intervals. However, more frequent than 48 hourly changes are not associated with any improvement.
The majority of complications of central lines are immediate complications that result from the insertion procedure.The main delayed complications are those of CVC-associated infection, and it is these which are focused upon in this article. This complication is a relatively frequent event, affecting around 5% of patients with an inpatient stay in the United States. Although this rate is falling, it is a severe event with mortality of between 12 and 25%.
CVCs can also be complicated by line dysfunction, where the CVC fails to function either due to increased resistance or blockage. This can be due to site, patient positioning, and formation of fibrin sheaths within the lumen and blocking the distal ports. it is possible to attempt to resolve a blockage through the use of alteplase or another fibrinolytic agent being inserted via the line in an attempt to dissolve the material.
Rarer complications include; fracture, where high pressures cause the CVC lumen to fracture, causing trauma to the vessel, central venous thrombosis, and stenosis associated with the CVC Site or portions of the catheter promoting coagulation and endovascular fibrous growth.
The impact of central line care is significant. When complications of central venous catheters occur they cause significant morbidity, increase length of stay, and delay recovery.
The relative cost of central line care interventions (increases in nursing care hours, relatively cheap dispensibles, and change to monitoring practices) compared to the morbidity of a CVC associated infection and the cost of the care for these complications.Depending on how the costs are estimated, the cost of treatment for these complications is thought to be between $3,700 and $39,000 in the USA and China and roughly 8,810 € per complication in Europe. The use of an appropriate dressing was recently calculated by the UK National Institute for Clinical Excellence to translate to a £93 saving per patient in comparison to the anticipated cost of infection and complication rates.The patient's perspective on their clinical outcomes should also not be underestimated. Many of the complications of CVCs can have chronic health impacts, may affect the patient's suitability for further treatments and procedures, and can increase the risk of future health issues.
Enhancing Healthcare Team Outcomes
There are a number of actions that can be implemented to improve the performance of central line care on a broader scale. Following and promoting hospital-specific or collaborative performance initiatives have been shown to improve compliance with evidence-based practice. The patient care team should perform CVC necessity reviews daily to ensure that central venous catheters are removed as soon as they are no longer necessary. Additionally, initiating and supporting a dedicated vascular team to address CVC insertion, maintenance, evaluation, and removal will decrease the incidence of central line complications.
Nursing, Allied Health, and Interprofessional Team Interventions
The following are a list of commonly recommended and implemented nursing care interventions for central lines.Education, Training, and Staffing
All healthcare professionals working in a setting with indwelling CVCs should receive annual training on central line care. Updates regarding indications for the placement of CVCs, maintenance of CVCs, and infection control measures should be included.
Facilities may institute a CVC care team. Having a dedicated team of personnel who demonstrate competence in maintaining central lines has been shown to decrease CLABSI. Additionally, ensuring adequate staffing in intensive care units (ICUs), decreasing the number of float nurses in the ICUs, and maintaining a low patient-to-nurse ratio reduces the incidence of catheter-related bloodstream infections.
Before the insertion of the central line, some traditional texts advocate bathing the patient from chin to ankle using chlorhexidine wash. This should be followed by preparing the skin for catheter placement by cleansing the insertion site thoroughly with chlorhexidine gluconate. Allow the area to dry fully before the provider proceeds with catheter insertion.
Sutureless securement devices should be used to reduce the risk of infection at the central line site.
Catheter Site Dressing Regimen
Central line dressings should not be changed every day unless they are loose or soiled. Current recommendations are to change gauze dressing every two days and transparent, semi-permeable dressing every seven days unless soiled or loose. If the patient is diaphoretic, has bleeding at the insertion site, or oozing from the insertion site, use a gauze dressing until the issue has resolved. Do not use topical antibiotic ointment or cream at the insertion site as this is ineffective. The exception would be with dressing changes to hemodialysis catheters, povidone-iodine, antiseptic ointment, or bacitracin/gramicidin/polymyxin B ointment may be applied to a hemodialysis catheter insertion site at the end of the dialysis session.
Frequent hand hygiene, sterile gloves for the practitioner performing care, and masks for the practitioner and patient are essential for dressing changes. After removing the soiled dressing, a new pair of sterile gloves should be donned before proceeding with the dressing change. A chlorhexidine-impregnated sponge dressing may be advisable if the CLABSI rate in the facility is not decreasing. At this and any other care opportunity, healthcare practitioners should perform a careful assessment of the catheter insertion site daily, ensuring the sutureless securement device is intact, noting the dressing change date listed on the dressing, and encouraging the patient to report any swelling or pain at the insertion site.
The patient with a central venous catheter should wash daily using chlorhexidine for skin cleansing.
Systemic Antibiotic Prophylaxis
Systemic antimicrobials should not be administered prophylactically in otherwise healthy patients. There are no indications that the prophylactic administration of systemic antimicrobials is beneficial, and the overuse of antimicrobials may lead to systemic resistance to these medications.
Replacement of Central Venous Catheters
Central lines should be removed as soon as they are no longer necessary. However, central venous catheters should not be routinely replaced. Routinely replacing central venous catheters have been shown to increase the incidence of infection at central line insertion sites. Additionally, central lines should not be removed based solely on the presence of hyperthermia. Other noninfectious causes of fever should be considered, and other evidence of infection should be sought before replacing an existing central venous catheter.
Replacement of Administration Sets
To decrease the incidence of CLABSI, intravenous (IV) administration sets should be changed no more frequently than every 96 hours but should be changed at least every seven days. IV tubing for blood, blood products, or fat emulsion product administration should be replaced within 24 hours of the initiation of the products. Additionally, IV tubing used for propofol administration should be changed at least every 6 to 12 hours or each time the vial is changed.
Needleless Intravenous Catheter Systems
The use of needleless IV catheter systems is highly recommended for reducing CVC complications. Needleless connectors and components should be changed with each IV administration set to change, no more frequently than every 72 hours. Access ports should be scrubbed with chlorhexidine, povidone-iodine, iodophor, or 70% alcohol and accessed only with sterile devices. All lumens are to be covered, preferably with disinfecting hub caps.
Nursing, Allied Health, and Interprofessional Team Monitoring
Nursing staff must be appropriately trained in the care of CVCs. Although the evidence for familiarity and training leading to reduced complications is not easy to develop or prove, there is limited evidence from a single study showing that impermanent staff caring for patients led to an increase in the rate of CVC associated infectious complications.