Establishing and Maintaining Vascular Access

Published on 04/03/2015 by admin

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Establishing and Maintaining Vascular Access

John C. Mansour and John E. Niederhuber

Summary of Key Points

• Three questions to ask when selecting a catheter system are: (1) Which device best meets the patient’s therapy and lifestyle needs? (2) How is the device most safely inserted and maintained? (3) What are the potential immediate and long-term complication risks?

• Types of central access systems are the traditional central line for short-term use, tunneled central lines for long-term use, surgically implanted infusion ports, and peripherally inserted central catheters.

• Vascular access devices can be placed using a number of anatomic sites to access the superior vena cava or inferior vena cava: the subclavian vein, internal jugular vein, external jugular vein, and femoral vein.

• Insertion can be performed via the Seldinger (closed) technique or by operative exposure of the vein (open technique).

• Short-term complications include vascular laceration, arterial puncture, pneumothorax (2%), hemothorax, and air embolus (overall placement complications should be <5%).

• Long-term complications include catheter exit site or tract infection, catheter-associated sepsis, cardiac arrhythmias, catheter colonization, catheter thrombus (~30%), fibrin sheath, extravasation, occluded catheter, and shearing of the catheter.

• Factors increasing the risk of catheter-associated infection include prolonged duration of indwelling time, multiple-lumen catheters, femoral locations, non–catheter-related bacteremia (in a neutropenic patient), the number of times the system is accessed, difficult catheter placement, and poor technique in catheter or port-site care.

Introduction

During the course of their disease, many patients with cancer require intravenous chemotherapy, frequent blood sampling, transfusion of blood products, or total parenteral nutrition. Many of these intravenously administered therapies are inflammatory to small peripheral veins. During the past three decades, techniques for obtaining and maintaining central vascular access have been developed and refined. Managing the treatment of patients with cancer requires a thorough familiarity with the special use of vascular access devices. This chapter provides a review of the pros and cons of various devices, insertion methods, and catheter maintenance techniques.

Few randomized controlled trials have examined the clinical controversies that are involved with chronic vascular access for patients with cancer. In addition, many of the larger studies regarding central vascular access were performed in the inpatient intensive care unit (ICU) setting. Comparing patients in the ICU with patients who have cancer and receive chemotherapy or weekly blood draws on an outpatient basis could lead to inaccurate conclusions. It is important, however, to review the available randomized trials, a number of carefully performed retrospective analyses, and pertinent ICU literature to address some of the questions concerning vascular access for patients with cancer.

When evaluating a patient who requires vascular access for treatment of a malignancy, three important questions must be answered: (1) What device will best meet this patient’s therapeutic needs? (2) How can we most safely insert and maintain central venous access? (3) What are the immediate and delayed complications of vascular access procedures that are unique to the oncology patient population?

Choosing the Right Device

Clinical oncologists use the vascular access devices discussed in this chapter to aspirate blood and infuse agents into central veins, such as the superior vena cava (SVC) or inferior vena cava. Many chemotherapeutic agents and parenteral nutrition formulations act as vesicants to the venous intima, causing inflammation and thrombosis of smaller veins. By infusing this type of product into the higher flow, less thrombogenic cardinal veins, the durability and safety of vascular access can be extended and patient comfort can be enhanced significantly.

Percutaneous Central Lines

Traditional central lines are placed with use of the Seldinger technique, which is described in detail later in this chapter. The subclavian vein, internal jugular vein, or femoral vein is cannulated percutaneously, and the catheter is placed with use of guide-wire assistance. There is a very short distance between the skin and the catheter’s entry point into the vein. Theoretically, this proximity to skin flora increases the risk of subsequent central line infection.

These central lines are in common use throughout most hospitals for patients with cancer, critically ill patients, or any patients who require infusions that are poorly tolerated via peripheral intravenous access. Such central lines provide excellent short-term access to the central venous system. In general, percutaneous central lines are considered only for short-term use, and after the first 7 to 10 days, percutaneous central lines have a markedly higher incidence of infection despite optimal skin entrance site dressing techniques. Obviously, prolonged patient neutropenia and episodes of bacteremia could result in shorter life spans of such catheters.

Patients with cancer who require a relatively short course of an infusion or need a bridge to placement of a more long-term catheter could benefit from these traditional central venous catheters. Meticulous sterile dressing changes are an absolute necessity for outpatients who need short-term therapy via these lines. Patients without the resources or dexterity to care for percutaneous central lines are at a prohibitively increased risk of line infection, bacteremia, or a thrombotic event and should be provided with a long-term form of central access. Certain comorbid conditions (e.g., burns, open wounds near the line site, or a tracheostomy) preclude placement of this type of vascular access.

Surgically Tunneled Central Lines

Most patients with cancer need a long-term form of central venous access rather than a traditional short-term central line. Surgically tunneled central lines were developed to increase the distance between the skin entrance site and the puncture of the vein. The hypothesis was that by increasing this distance, the life span of the central access would be increased by decreasing the incidence of infection and thrombosis. Tunneled central lines are commonly referred to by the name of the first brand that was marketed—Hickman. Other examples include Broviac, Quinton, and Groshong (Fig. 26-1). These polymeric silicone rubber venous access catheters are placed via a subcutaneous tunnel that is described in detail later in this chapter. Clinical studies have supported the hypothesis that increasing the distance between the catheter exit site in the skin and the hole in the vein decreases the incidence of externally derived infection.1,2 Studies suggest that the incidence of bloodstream infections associated with tunneled catheters is approximately 1 to 2 per 1000 catheter days.3 The frequency of bacteremia among nontunneled catheters has been reported at between 1.0 and 13.0 per 1000 catheter days.66

A Dacron cuff located 3 to 4 cm from the exit site encourages scar formation to fix the catheter in place. This exaggerated scarring eliminates the need for long-term sutures to hold the catheter in place to the skin. Avoiding these fixation sutures can decrease the incidence of stitch reactivity and associated localized skin infections. One drawback of this type of central access device is the inconvenience of placing and removing the lines. In most instances, surgeons or interventional radiologists insert these lines under local anesthetic and intravenous sedation. Therefore these procedures require coordination of the patient, the surgeon or interventional radiologist, and possibly the anesthesia/operating room staff. Tunneled catheters are more uncomfortable to remove than are nontunneled lines because of the Dacron cuff scar reaction. Removal requires local anesthesia but can be accomplished outside of the operating room.

Surgically Implanted Infusion Ports

Implantable ports consist of a small injection reservoir with a self-sealing membrane placed entirely beneath the skin. There is no external catheter. An internal catheter runs from the reservoir into the subclavian or internal jugular vein to provide central access. The internal catheter is essentially identical to those used for tunneled central lines. A noncoring (Huber) needle can pass directly through the skin into the reservoir for infusion or aspiration. The self-sealing rubber cap on the reservoir prevents leakage from the reservoir after withdrawal of the Huber needle. The gauge of the noncoring needle—not the catheter—typically limits flow through the port system (Fig. 26-2). The ports can also be used for continuous drug infusion, as shown in Figure 26-3.

The theoretical concern that bacteria more easily traverse the short distance between the skin and the “neo-vein” or reservoir and cause increased rates of infection does not prove true.7 Sterile technique and site care lead to an infection risk comparable with that of tunneled catheters. With adequate care, the rate of infection could be fourfold to fivefold less than that for tunneled catheters.3 The low rate of infection and extravasation make infusion ports ideally suited for patients with cancer who need long-term single-lumen access and a low-maintenance catheter. However, experience has shown that patients with prolonged periods of neutropenia or significant risk of cutaneous eruptions might not be good candidates for port devices. The visible lump of the port could bother extremely thin patients; however, the port on the anterior chest wall is easily hidden from plain view for most people.

Long-Line Central Access

Also known as a peripherally inserted central catheter (PICC line), the long-line central access vascular access device is becoming increasingly popular. The catheter is inserted into a brachial, cephalic, or antecubital vein and advanced into the subclavian vein or higher. These lines can be placed simply and easily in the outpatient office setting and are well tolerated by patients, with minimal risk. However, many patients with cancer have poor-quality arm veins after undergoing multiple peripheral infusions and are therefore poor candidates for this technique. The 50% risk of catheter-related thrombosis is the greatest drawback to more widespread use of PICC lines in patients with cancer. This problem is a result of the presence of a long length of catheter within the vein and to the catheter tip in the relatively low-flow subclavian vein. Advancing the catheter tip into the SVC can reduce the incidence of thrombosis by more than half.8 Accurate placement of the catheter tip in the SVC can be complicated by the large displacement of the catheter tip (up to 8 cm) with normal arm range of motion.9

Inserting Vascular Access Devices

Providing patients who are undergoing treatment for cancer with appropriate vascular access requires not only a thorough knowledge of available devices but also technical expertise in the procedures for placing these catheters. Although these procedures are sometimes viewed as routine, the risks of poor technique can be devastating for the patient. Before undertaking the procedure, the physician should carefully consider everything from the site of insertion to the dressing to be used at the end of the procedure (Table 26-1).

Table 26-1

General Guidelines for Catheter and Port Use

Type Advantages Uses Dressings Flushing Comments
Central line Placed at bedside Hospital use only Sterile transparent dressing 5 mL heparinized saline solution (10 units/mL) in each lumen daily or after each use Antibiotic ointment may promote resistance
  Easy removal        
  One or multiple lumens   Change dressing twice weekly    
  Can change over wire        
PICC catheter Safe to insert and remove 1 wk to 6 mo of IV access Transparent antimicrobial foam dressing 3 mL heparinized saline solution bid or after each use Flush and draw blood slowly to avoid catheter migration
      Change every 6 days    
Hickman catheter Multiple sizes and lumens Continuous infusion therapy Newly placed: antimicrobial dressing for 7 to 10 days 5 mL heparinized saline solution daily or after each use Clean with chlorhexidine during dressing change
  Tunneled under skin Long-term access      
      Gauze or transparent dressing changed 2 times per wk   After 4 wk may clean with antimicrobial soap
Groshong catheter Slit valve requires no heparin flushes Single- or double-lumen catheter for long-term use      
  Smaller, more flexible catheter        
Port Completely under skin One lumen access and low maintenance None 5 mL heparinized saline solution daily or after each use Clean with chlorhexidine before use, access with noncoring needle
  Minimal care     20 mL saline solution after blood draw  
        Monthly flush with 5 mL heparinized saline solution (100 units/mL) Use no needle >20 gauge to access;
EMLA cream helpful

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bid, Twice a day; EMLA, eutectic mixture of local anesthetics; IV, intravenous; PICC, peripherally inserted central catheter.

Choosing Insertion Location

Vascular access devices can be placed with use of a number of different access points, including the internal jugular, subclavian, external jugular, and femoral veins. The vast majority of catheters that are used for long-term vascular access in patients with cancer are placed in the internal jugular and subclavian veins. We will limit this discussion to these most common access sites.

The most frequent site for insertion of vascular access devices in the oncology population is the subclavian vein. Clavicular fracture or a previous median sternotomy can alter the anatomy of this location. For a patient with such a history, an alternative site should be considered. Even for patients with standard venous anatomy, the acute angle at the confluence of the subclavian and internal jugular veins at the brachiocephalic vein can complicate the passing of the guide wire into the SVC. A higher incidence of pneumothorax, hemothorax, and catheter malposition occurs among inexperienced operators, and a higher incidence of vein stenosis occurs with subclavian vein placement than with internal jugular placement.10 A subclavian artery puncture during line placement can be difficult to control because of the position of the artery posterior to the clavicle. A catheter placed on the anterior chest wall is more comfortable and easier to cover with clothing, however, than is a line in the neck.

In many ways, the internal jugular vein is the ideal location with regard to ease of placement of a central catheter. The path of the guide wire during placement is straight, thereby limiting many guide-wire complications and catheter malposition. In the event of carotid artery puncture, arterial bleeding can be controlled safely with the application of direct pressure. This advantage is especially important in the patients with thrombocytopenia. The incidence of central venous occlusion is decreased, which could be important for patients who are likely to need an arteriovenous fistula for hemodialysis in the future. Unfortunately, patients often report pain with neck and shoulder movements after placement of an internal jugular catheter.

Preparing to Place the Vascular Access Device

Adequate preparation for placing a central venous catheter in a patient with cancer includes several steps before the actual line insertion. The surgeon must make several decisions that can limit the incidence of both immediate and delayed complications and ensure optimal line function.

Studies suggest that providing a single dose of prophylactic antibiotic to cover common skin flora before inserting the vascular access device reduces central line infection. However, it is difficult to determine how this small benefit affects antibiotic resistance and subsequent infections. Use of central venous catheters impregnated with antibiotics could be more effective in dealing with infectious complications and will be discussed later in this chapter.11

A sterile surgical field with mask, gown, cap, gloves, and a large sterile drape should be used to minimize the risk of line infection.12 The skin of the entire anterior neck and chest should be prepared with chlorhexidine, which is superior to povidone-iodine or alcohol in limiting line infections.13,14

The choice to use ultrasound guidance to identify the vein during cannulation should be addressed before beginning the procedure. Less-experienced operators will likely benefit from the use of ultrasound guidance as an adjunct to the anatomic landmarks technique.15,16 Ultrasound can decrease the incidence of arterial puncture and placement failure. Although a few reports exist in the literature regarding the advantage of these techniques, such superiority is often judged when compared with high rates of complications using the landmark approach as the control group.

The operator must also decide where to position the catheter tip within the central vein. Catheters positioned with the tip in the right atrium will function longer as a source for aspirating blood samples than will those with the tip positioned in the SVC.17,18 A case review of thrombosed catheters documents that the position of the tip of the catheter at the time of thrombosis seems to be the most important contributing factor.19,20

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