The Use of Venous Access Devices in Pediatric Oncology Nursing Practice Diane Keegan-Wells,
RN, MSN and Janet L. Stewart, RN, MS
Venous access devices have been in use since 1973 and have made a tremendous impact on care of children with malignancies to facilitate the delivery of complex medical care and minimize the trauma associated with cancer therapy. During the past 20 years the variety and complexity of available devices has resulted in an increased demand for technical knowledge and expertise to prevent complications and assure safe use. This article reviews the various devices, complications and implications for nursing practice, and recommendations for
pediatric nursing regarding patient/parent
self-care and
developmental safety
issues.
BEFORE
THE
development
of central
ve-
devices (VADs), children unfor cancer faced multiple indergoing therapy travenous (N) punctures for the administration of therapy and the sampling of blood. Difficulties with establishing and maintaining peripheral venous access complicated the delivery of care both medically and psychosocially, sometimes to the point of therapy being interrupted or stopped. Today the use of VADs has made a tremendous impact on children who are being treated for malignancies, offering many patients a safe, comfortable, and reliable alternative to nous access
peripheral venous
access.
Broviac catheters were first introduced in 1973 for patients who required long-term hyperalimentation. Hickman and his colleagues in 1976 introduced a larger, more versatile catheter that could be used for chemotherapy, blood 1 product administration, and blood drawing.’ Both the Broviac and Hickman Silastic catheters are appropriate not only for inpatient treatment but also for care in the outpatient setting and in From the Department of Pediatric Hematology/ Oncology, University of Maryland Hospital, Baltimore, MD, and the Department of Pediatric Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH. Address reprint requests to Diane Keegan-Wells, RN, MSN, Clinical Nurse Specialist Pediatric Hematology/ Oncology, University of Maryland Hospital, 22 S Greene . St, Baltimore, MD 21201.
the home. Thus, central lines have become a very important part of nursing management of the pediatric oncology patient. The last decade has seen further progress in the development of new types of VADs, most notably implanted ports and peripherally inserted central catheters. Whereas this progress has revolutionized the approach to venous access in the pediatric cancer patient, we are now faced with complicated choices previously unknown to patients and care providers. Pediatric
oncology nursing practice now incorporates responsibility for managing and maintaining central venous access, including establishing the best choice of VAD for the individual patient, educating patient, family, and staff in the use of VADs, and anticipating and intervening with problems that arise. The purpose of this article is to compare the of VADs, to review complications of each type of device and implications for nurs-
existing types
ing practice and, finally, to provide recommendations for pediatric nursing practice regarding patient/parent self-care and developmental safety issues. Indications for Use of VADs The complex medical management of children with malignancies makes the use of VADs a common practice in pediatric oncology. Initially, VADs were considered only for children 159
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160
with problematic peripheral venous access. A second population of patients, those with frequent or long-term venous access needs, were subsequently considered for placement of VADs. Over the years, additional patients became candidates for these devices, including children who required home infusions or frequent administration of vesicant agents. Gradually the use of VADs has evolved to include the large majority of children with inalignancies such that VADs are placed according to patient, parent, and caregiver preference to facilitate the delivery of complex medical care and to minimize the trauma associated with cancer therapy.
Types
of VADs
The four
categories of catheters used in the pediatric setting are: (1) percutaneous central venous (nontunneled) catheters; (2) silastic (tunneled) catheters; (3) implanted ports; and (4) peripherally inserted central catheters (Figs 1-4). These devices share several common characThey are constructed of radiopaque material to facilitate the determination of line placement. They are usually inserted into a major vein of the neck, chest, or arm with the distal tip lying in the superior vena cava (SVC) or right atrium of the heart. In conditions precluding cannulation of the SVC, for example, thrombosis of the brachycephalic or subclavian veins, or tumor of the neck or chest, central lines can be placed via veins in the lower extremities (eg, saphenous vein) and advanced to the inferior vena teristics.
cava.2 The various types of VADs, although sharing the goal of establishing access to the central circulation, have many differences that should be considered when determining their suitability for an individual patient’s care. The following discussion of the different VADs will serve as a basis of comparison for each device’s advantages and limitations. The information included in the discussion is summarized in Table 1, which serves as a framework for comparing the cost/benefit ratio of each device to assist with the selection of a catheter based on patient characteristics.
Percutaneous Central Venous Catheters Percutaneous catheters are usually made of Silastic or plastic (eg, polyurethane, polypropyl-
polyvinyl, or Teflon) and are placed into the central circulation via a direct puncture into a large vein, usually the subclavian or jugular vein (Fig 1). The catheter is sutured to the skin, and the site is covered with an occlusive dressing. These lines are used primarily for patients who ene,
require venous access for a limited period of time, although in some cases they have been
kept in place as long as 300 days. 3,4 Because they can either be placed or removed with local anesthesia, these catheters
are
appropriate for
patients who are not candidates for general anesthesia. They, are also useful for patients in whom it is not ideal to establish a permanent line, such as the patient with septicemia. Multiple-lumen catheters are available for patients with complex medical regimens requiring the simultaneous infusion of incompatible fluids or medications. Removal of a nontunneled catheter is accomplished as easily as the removal of an IV catheter, although pressure must be sustained during its removal from a large vessel. Limitations of nontunneled catheters include the risk of complication with plastic catheters during placement, such as pneumothorax or arterial puncture,5 dislodgement because there is no cuff to secure it in place, and an increased risk of infection because there is no tunnel or antimicrobial cuff as a barrier to infection under the skin. Because of the increased risk of dislodgement and potential for infection, these catheters may restrict patient activities such as showering and swimming. Therefore, they are not recommended for longterm venous access in pediatric oncology patients, although they can be extremely useful in the acute
care
setting.
Tunneled Central Venous Catheters The most frequently used central venous catheters in children with cancer are Silastic catheters (Fig 2). These single or multiplelumen catheters are tunneled subcutaneously for several inches from the insertion site in the central circulation to the desired exit site. A small cuff attached to the catheter lies under the skin close to the exit site, providing both catheter security and a barrier to infection. Ingrowth of the cuff to subcutaneous tissue takes approximately 14 to 28 days and limits bacterial migration up the catheter to the venous circulation. Studies
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161
TABLE l..
,
Compaiison of VAD§ .
show a decreased rate of catheter infection when the cuff is more than 3 cm from the exit
site 6 Surgical placement of a tunneled catheter requires two small incisions through the skin in the area of the vein to be accessed and at the exit site. A subcutaneous tunnel is created between the two, and the catheter is inserted through the distal incision with the cuff positioned within the subcutaneous tunnel. After being advanced through the subcutaneous tunnel, the catheter is inserted into a large vein, usually the subclavian or jugular vein (for catheters placed in the chest) or into the saphenous vein. The catheter is further advanced until the tip lies in the superior or inferior vena cava or at the junction of the right atrium. Although surgical placement of a tunneled
catheter can be accomplished with local anesthesia alone, the discomfort associated with extensive local anesthesia and the prolonged placement time makes the use of general anesthesia ideal, if not mandatory, for the placement of tunneled lines in children. In addition, the strict aseptic technique used in the operating room is optimal for the prevention of catheter infection during placement Removal of a tunneled catheter can usually be done with local anesthesia and conscious sedation, but it may required general anesthesia depending on patient characteristics such as age and potential for anxiety as well as the surgeon’s evaluation of
procedure safety. Limitations of this type of catheter for longcare include an undesirable cosmetic effect because the catheter is external
term use or home
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162
infection in immunocompromised patients. Infections can occur such as sepsis, localized exit site infection, and/or tunnel infections.
Implanted Infusion Ports devices have been developed provide long-term, reliable central venous access (Fig 3). These dome-shaped ports are usually constructed of a metal or plastic casing with a raised septum made of self-sealing rubber. A noncoring needle is inserted through the skin and septum of the device into a reservoir that connects to the central circulation via a Silastic catheter. Surgical insertion of the implanted port is performed under general anesthesia. Two small incisions are made. The first is made over the vein in which the catheter will be placed. The second incision is used to make a subcutaneous pocket between the skin and a large muscle, usually on the chest wall, although ports can also be placed in the abdomen or the lateral ribs. The attached catheter is inserted into a large vein and advanced until its tip lies in the superior or inferior vena cava. The port is then sutured to the fascia of the muscle with the overlying skin providing a barrier to infection. Once the surgical incision is healed, the port is visible only as a small raised area under the skin and requires no home care when not in use. This aspect of implanted ports greatly reduces the impact on body image. Accessing an implanted port requires a skin puncture, which can be made more comfortable
Totally implantable that
FIGURE 1. Percutaneous central venous catheter (Reprinted with permission from Bard Access Systems, Salt Lake City, UT).
body and can be difficult to conceal. This particularly disturbing to adolescents. In addition, an external catheter can limit participa-
to the can
be
tion in contact sports, and, depending on institutional practice, it may preclude or limit swim-
ming. Another drawback to the use of externalized catheters is the level of care they require to prevent infection and occlusion. Home care of external catheters requires a minimum level of competence, cleanliness, and time commitment that not all families can fulfill. Likewise, there are financial considerations related to the cost of home care supplies, such as flushing solutions and dressing equipment, which may or may not be covered by third-party reimbursement. And finally, despite conscientious hospital and home care techniques for maintaining tunneled catheters, there remains a significant risk of catheter
FIGURE 2. Tunneled central venous catheters (Reprinted with permission from Bard Access Systems, Salt Lake
City, tIT).
FIGURE 3. Implanted infusions port (Reprinted with permission from Bard Access Systems, Salt Lake City, UT).
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163
with the use of transcutaneous or subcutaneous anesthetics. Young patients may continue to exhibit aversive reactions to the needle stick associated with port accession, but most patients report that it is much less traumatic than venipuncture. Once the port needle is in place and secured with an occlusive dressing, it can be used much like an external catheter for infusion of medications, fluids, and blood products, and for blood sampling, without additional painful sticks. The port needle can also be used as a heparin lock by placing an injection cap on the end of a noncoring needle with an extension set. When used as a heparin lock, it should be flushed in accordance with institutional guidelines for central venous catheters. When not in use, the port requires flushing with a heparinized solution approximately every 4 weeks. ~11 infusion ports require the use of noncoring needles, either straight or 90° angle needle with extension set. The port is accessed by injecting the needle perpendicular to the skin for entry into the device (ie, in the same manner as an intramuscular injection). In addition, several manufacturers produce a port constructed in such a way that the noncoring needle should be inserted parallel to the skin (ie, the same manner in which an 1~ catheter is placed). It is essential that caregivers know which type of device the patient has in order to place the needle correctly. Limitations of this type of device include the trauma associated with needle sticks, which may make it an inappropriate choice for the needlephobic patient whose medical regimen requires frequent access to the central circulation. Also, there is a significant risk of needle dislodgement from the port during continuous infusions, resulting in subcutaneous infiltration of drug or fluids. This can be particulariy harmful for patients receiving vesicant drugs or parenteral nutrition. Because the port is completely implanted, troubleshooting problems such as occlusion or infection may be more difficult. Removal of the port, a procedure that requires general anesthesia, is more extensive than removal of an external catheter. As with external catheters, infection is a potential complication. infections related to implanted ports can manifest either as soft tissue infection within the subcutaneous pocket where the port is secured or as sepsis. Several studies have compared infection rates in implanted
ports with externalized tunneled catheters. Ross
reported that infection occurred less frequently in implanted ports than in externalized catheters in children with cancer. Mirro et al et al
found that ports had a lower rate of infection than catheters overall, but this difference was not significant when subjects were matched for age and clinical characteristics.8 A study by Wurzel et al comparing infection rates of BroviacHickman catheters and implantable venous devices in pediatric oncoiogy patients showed no significant differ ence in infection rate.9 lt remains to be seen whether the increased use of implanted ports in medically compromised patients will result in an infection rate similar to that seen with the use of tunneled catheters.
Peripherally Inserted
Central Catheters
Because some long-term patients are not candidates for centrally inserted catheters, alternatives to traditional peripheral 1’~ lines have been developed. Peripherally inserted central catheters (PICCs) are used primarily with patients in the home care setting who require prolonged courses of antimicrobial therapy and in intensive care settings (Fig 4). PICCs have had limited use with pediatric oncology patients, but they may be appropriate for children who do not have centrally established devices that need more frequent or continuous peripheral access. For example, in the care of the terminally ill child who is not a candidate for anesthesia for placement of a tunneled catheter,
FIGURE 4.
Peripherally inserted central catheter (pict) (Reprinted permission from Bard Access Systems, Salt Lake
City,, UT).
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164
the PICC could offer a parenteral route for symptom management at home. These polyurethane or Silastic catheters are placed, preferably with local anesthesia, through the antecubital fossa into either the basilic or cephalic vein and threaded into the subclavian vein or SVC. The catheter is secured with an occlusive dressing and may remain in place for up to 3 months.10 Because PICC lines have not been in use for an
extended
period of time, complication
rates
have not been established. Some discomfort and limitation of mobility may be associated with line placement in the antecubital fossa.
Complications Associated With VAL7s Complications of VADs fall into six major categories : infection, cutaneous reactions, occlusion, catheter misplacement, SVC syndrome, air embolism, and catheter breakage. Nursing management of patients with VADs requires the understanding of these complications and the use of appropriate interventions to prevent or manage them. Infection can result from contamination of (1) the catheter during placement, (2) the infusion system during use, or (3) the catheter exit site. Risk of contamination during placement is reduced with appropriate use of sterile technique either in the operating room or at the bedside. Hayward identified two additional factors associated with insertion-related infection: neutropenia or fever >101°F on the day of catheter in-
sertion.6 More commonly, the VAD becomes colonized by bacteria either at the exit site or through the infusion system. Studies of institutional incidence of central line infection are difficult to compare because of differences in patient populations, duration of catheter use, types of cath-
used, surgical techniques, dressing change protocols, and data collection procedures. Rates of infection have been reported to range from 25% to 55% .7-9,11-15 In a study of central line infections in pediatric cancer patients, Johnson reported a low incidence of catheter-related septic episodes per catheter use days, but almost 50% of the patients in the study had at least one episode of catheter infection. 15 Infection in the immunocompromised patient can be life-threatening eters
and may necessitate VAD removal. The timely initiation of broad-spectrum antimicrobial agents in the febrile, neutropenic patient has become standard in pediatric oncology practice and has greatly reduced the risk of overwhelming sepsis; thus, VADs are not usually removed at the first sign of fever. There is a growing body of literature that supports treating VAD-related infections with topical and/or intravenous antimicrobials in an attempt to clear the infection without removal of the device. Reports of successfully treated VAD infection without removal range from 38% to 89%.~’~-~ Several studies have compared skin cleansing technique with dressing change protocols and their effect on the incidence of exit site infections in patients with catheters. Most of these studies show no difference between various antiseptic techniques or between gauze dressing and transparent dressings.’ &dquo;,’9 In addition, in a comparison of two brands of transparent dressing, gauze dressing, and no dressing at all, Petrosino et al found no difference in infection rates between the four groups.’ 9 Bagnall-Reeb and Ruccione, in a retrospective study, describe the treatment of local staphylococcus wound infections with Neosporin (Burroughs-Wellcome Company, Research Triangle Park, NC) or Bactroban (Beechum Laboratories, Bristol, TN) and local yeast infections with Mycostatin or Mycolog ointment (ER Squibb & Sons, Inc, Princeton, NJ). Of 13 exit site infections treated topically, only 3 failed to respond and required IV antibiotic therapy. Two of the three eventually required catheter removal. 20 Although many local and systemic infections will resolve with treatment, some will still require catheter removal. Indications for removing an infected VAD include the presence of large numbers of bacterial colonies isolated from blood cultures as well as evidence of soft tissue infection, such as exudate and/or erythema 11.16,21 that are not responsive to topical or systemic therapy. Decker and Edwards, in a review of the infectious disease literature, describe how blood cultures drawn both centrally and peripherally with a ratio of bacteria five times greater in the central than peripheral circulation are unlikely to be sources of infection other than the catheter. 22 Most institutions use some form of occlusive
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.
165
exit site of tunneled catheters. Cutaneous reactions to dressing materials and solutions occur in some patients. These reactions can range from mild to severe and may predispose the patient to local infection and significant discomfort. Nursing management for these problems is well described in BagnallReeb and Ruccione. 20 Total or partial catheter occlusion is the second most common problem associated with VADs. Occlusion can result either from drug precipitation or from formation of a fibrin clot within the lumen of the catheter. Drug precipitation can occur when incompatible solutions or drugs are given simultaneously or without proper clearing of the line between administration of medications. This type of occlusion does not resolve with the use of fibrinolytic agents, is very difficult to clear, and may necessitate the removal of the catheter. Shulman et al describe safely using 0.2 to 1.0 mL of 0.1 N (normal) hydrochloric acid to clear drug precipitates in four occluded central venous catheters that did not clear with fibrinolytics 23 Patency was restored after leaving the solution in the catheter for several hours. Occasionally clinicians have had success clearing drug precipitates with the infusion of fluids without additives, such as normal saline or D5W at a rate of 20 to 40 mL. Formation of clots within the lumen of the catheter can usually be avoided by the careful and regular use of flushing solutions after infusions or blood drawing. The Groshong catheter (CR Bard, Inc, Cranston, RI) requires only saline flush to maintain patency, however there is a lack of consensus regarding flush solutions required for other VADs. Most institutions use heparinized saline in concentrations ranging from 10 pfmL to 1,000 wlmL to maintain patency in intermittently accessed lines or ports, although some institutions advocate saline-only flushing. Different regimens used include flushing every 12 hours, daily, or weekly. In a recent study comparing heparin I O p/mL twice a day with weekly 9-ml flush of isotonic saline, no difference in clot formation was found. 24 Therefore, the use of low-dose heparin or saline may therefore be
dressing over the
.
preferable to introduce less systemic heparin. Even with appropriate flushing of catheters, fibrin clots can form at the tip of the catheter,
causing either partial or total catheter occlusion. Fibrin sheaths can form around the outside of the catheter creating outflow obstruction. In this situation, fluids can be infused, but blood cannot be withdrawn. Sometimes this condition can be alleviated by repositioning the patient, having the patient perform a Valsalva maneuver, or administering 10 mL or more of saline before blood withdrawal. When these strategies are ineffective, fibrinolytic agents can be used to remove the fibrin that is obstructing blood withdrawal. Likewise, if the lumen or tip of a catheter becomes completely occluded with a blood clot such that fluid cannot be administered nor blood withdrawn, patency can usually be restored with the use of a fibrinolytic agent. Urokinase is currently recommended over streptokinase because of the reduced incidence of antigenic reaction.25 Preliminary data document the safe use of tissue plasminogen activator for clearing occluded catheters that do not respond to
fibrinolytics.26
The urokinase product literature describes the procedure for declotting catheters with a fibrinolytic agent To determine the appropriate volume of urokinase to instill per catheter, first determine the size and brand of catheter and refer to the manufacturer’s recommended priming volume. If this information is not available, the priming volume can be estimated by determining the amount of fluid or vacuum measured when a syringe plunger is pulled back withdrawing the contents of the catheter before obtaining blood return. The half-life of fibrinolytic agents is in the range of 10 to 60 minutes, allowing for repeated administrations in an attempt to restore catheter patency. Brown et al report experience with adults in administration of four separate doses within a 24-hour period and up to three doses in 4 hours without systemic effects. For thrombocount
RN, MSN and Janet L. Stewart, RN, MS
Venous access devices have been in use since 1973 and have made a tremendous impact on care of children with malignancies to facilitate the delivery of complex medical care and minimize the trauma associated with cancer therapy. During the past 20 years the variety and complexity of available devices has resulted in an increased demand for technical knowledge and expertise to prevent complications and assure safe use. This article reviews the various devices, complications and implications for nursing practice, and recommendations for
pediatric nursing regarding patient/parent
self-care and
developmental safety
issues.
BEFORE
THE
development
of central
ve-
devices (VADs), children unfor cancer faced multiple indergoing therapy travenous (N) punctures for the administration of therapy and the sampling of blood. Difficulties with establishing and maintaining peripheral venous access complicated the delivery of care both medically and psychosocially, sometimes to the point of therapy being interrupted or stopped. Today the use of VADs has made a tremendous impact on children who are being treated for malignancies, offering many patients a safe, comfortable, and reliable alternative to nous access
peripheral venous
access.
Broviac catheters were first introduced in 1973 for patients who required long-term hyperalimentation. Hickman and his colleagues in 1976 introduced a larger, more versatile catheter that could be used for chemotherapy, blood 1 product administration, and blood drawing.’ Both the Broviac and Hickman Silastic catheters are appropriate not only for inpatient treatment but also for care in the outpatient setting and in From the Department of Pediatric Hematology/ Oncology, University of Maryland Hospital, Baltimore, MD, and the Department of Pediatric Oncology, Dartmouth-Hitchcock Medical Center, Lebanon, NH. Address reprint requests to Diane Keegan-Wells, RN, MSN, Clinical Nurse Specialist Pediatric Hematology/ Oncology, University of Maryland Hospital, 22 S Greene . St, Baltimore, MD 21201.
the home. Thus, central lines have become a very important part of nursing management of the pediatric oncology patient. The last decade has seen further progress in the development of new types of VADs, most notably implanted ports and peripherally inserted central catheters. Whereas this progress has revolutionized the approach to venous access in the pediatric cancer patient, we are now faced with complicated choices previously unknown to patients and care providers. Pediatric
oncology nursing practice now incorporates responsibility for managing and maintaining central venous access, including establishing the best choice of VAD for the individual patient, educating patient, family, and staff in the use of VADs, and anticipating and intervening with problems that arise. The purpose of this article is to compare the of VADs, to review complications of each type of device and implications for nurs-
existing types
ing practice and, finally, to provide recommendations for pediatric nursing practice regarding patient/parent self-care and developmental safety issues. Indications for Use of VADs The complex medical management of children with malignancies makes the use of VADs a common practice in pediatric oncology. Initially, VADs were considered only for children 159
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160
with problematic peripheral venous access. A second population of patients, those with frequent or long-term venous access needs, were subsequently considered for placement of VADs. Over the years, additional patients became candidates for these devices, including children who required home infusions or frequent administration of vesicant agents. Gradually the use of VADs has evolved to include the large majority of children with inalignancies such that VADs are placed according to patient, parent, and caregiver preference to facilitate the delivery of complex medical care and to minimize the trauma associated with cancer therapy.
Types
of VADs
The four
categories of catheters used in the pediatric setting are: (1) percutaneous central venous (nontunneled) catheters; (2) silastic (tunneled) catheters; (3) implanted ports; and (4) peripherally inserted central catheters (Figs 1-4). These devices share several common characThey are constructed of radiopaque material to facilitate the determination of line placement. They are usually inserted into a major vein of the neck, chest, or arm with the distal tip lying in the superior vena cava (SVC) or right atrium of the heart. In conditions precluding cannulation of the SVC, for example, thrombosis of the brachycephalic or subclavian veins, or tumor of the neck or chest, central lines can be placed via veins in the lower extremities (eg, saphenous vein) and advanced to the inferior vena teristics.
cava.2 The various types of VADs, although sharing the goal of establishing access to the central circulation, have many differences that should be considered when determining their suitability for an individual patient’s care. The following discussion of the different VADs will serve as a basis of comparison for each device’s advantages and limitations. The information included in the discussion is summarized in Table 1, which serves as a framework for comparing the cost/benefit ratio of each device to assist with the selection of a catheter based on patient characteristics.
Percutaneous Central Venous Catheters Percutaneous catheters are usually made of Silastic or plastic (eg, polyurethane, polypropyl-
polyvinyl, or Teflon) and are placed into the central circulation via a direct puncture into a large vein, usually the subclavian or jugular vein (Fig 1). The catheter is sutured to the skin, and the site is covered with an occlusive dressing. These lines are used primarily for patients who ene,
require venous access for a limited period of time, although in some cases they have been
kept in place as long as 300 days. 3,4 Because they can either be placed or removed with local anesthesia, these catheters
are
appropriate for
patients who are not candidates for general anesthesia. They, are also useful for patients in whom it is not ideal to establish a permanent line, such as the patient with septicemia. Multiple-lumen catheters are available for patients with complex medical regimens requiring the simultaneous infusion of incompatible fluids or medications. Removal of a nontunneled catheter is accomplished as easily as the removal of an IV catheter, although pressure must be sustained during its removal from a large vessel. Limitations of nontunneled catheters include the risk of complication with plastic catheters during placement, such as pneumothorax or arterial puncture,5 dislodgement because there is no cuff to secure it in place, and an increased risk of infection because there is no tunnel or antimicrobial cuff as a barrier to infection under the skin. Because of the increased risk of dislodgement and potential for infection, these catheters may restrict patient activities such as showering and swimming. Therefore, they are not recommended for longterm venous access in pediatric oncology patients, although they can be extremely useful in the acute
care
setting.
Tunneled Central Venous Catheters The most frequently used central venous catheters in children with cancer are Silastic catheters (Fig 2). These single or multiplelumen catheters are tunneled subcutaneously for several inches from the insertion site in the central circulation to the desired exit site. A small cuff attached to the catheter lies under the skin close to the exit site, providing both catheter security and a barrier to infection. Ingrowth of the cuff to subcutaneous tissue takes approximately 14 to 28 days and limits bacterial migration up the catheter to the venous circulation. Studies
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161
TABLE l..
,
Compaiison of VAD§ .
show a decreased rate of catheter infection when the cuff is more than 3 cm from the exit
site 6 Surgical placement of a tunneled catheter requires two small incisions through the skin in the area of the vein to be accessed and at the exit site. A subcutaneous tunnel is created between the two, and the catheter is inserted through the distal incision with the cuff positioned within the subcutaneous tunnel. After being advanced through the subcutaneous tunnel, the catheter is inserted into a large vein, usually the subclavian or jugular vein (for catheters placed in the chest) or into the saphenous vein. The catheter is further advanced until the tip lies in the superior or inferior vena cava or at the junction of the right atrium. Although surgical placement of a tunneled
catheter can be accomplished with local anesthesia alone, the discomfort associated with extensive local anesthesia and the prolonged placement time makes the use of general anesthesia ideal, if not mandatory, for the placement of tunneled lines in children. In addition, the strict aseptic technique used in the operating room is optimal for the prevention of catheter infection during placement Removal of a tunneled catheter can usually be done with local anesthesia and conscious sedation, but it may required general anesthesia depending on patient characteristics such as age and potential for anxiety as well as the surgeon’s evaluation of
procedure safety. Limitations of this type of catheter for longcare include an undesirable cosmetic effect because the catheter is external
term use or home
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162
infection in immunocompromised patients. Infections can occur such as sepsis, localized exit site infection, and/or tunnel infections.
Implanted Infusion Ports devices have been developed provide long-term, reliable central venous access (Fig 3). These dome-shaped ports are usually constructed of a metal or plastic casing with a raised septum made of self-sealing rubber. A noncoring needle is inserted through the skin and septum of the device into a reservoir that connects to the central circulation via a Silastic catheter. Surgical insertion of the implanted port is performed under general anesthesia. Two small incisions are made. The first is made over the vein in which the catheter will be placed. The second incision is used to make a subcutaneous pocket between the skin and a large muscle, usually on the chest wall, although ports can also be placed in the abdomen or the lateral ribs. The attached catheter is inserted into a large vein and advanced until its tip lies in the superior or inferior vena cava. The port is then sutured to the fascia of the muscle with the overlying skin providing a barrier to infection. Once the surgical incision is healed, the port is visible only as a small raised area under the skin and requires no home care when not in use. This aspect of implanted ports greatly reduces the impact on body image. Accessing an implanted port requires a skin puncture, which can be made more comfortable
Totally implantable that
FIGURE 1. Percutaneous central venous catheter (Reprinted with permission from Bard Access Systems, Salt Lake City, UT).
body and can be difficult to conceal. This particularly disturbing to adolescents. In addition, an external catheter can limit participa-
to the can
be
tion in contact sports, and, depending on institutional practice, it may preclude or limit swim-
ming. Another drawback to the use of externalized catheters is the level of care they require to prevent infection and occlusion. Home care of external catheters requires a minimum level of competence, cleanliness, and time commitment that not all families can fulfill. Likewise, there are financial considerations related to the cost of home care supplies, such as flushing solutions and dressing equipment, which may or may not be covered by third-party reimbursement. And finally, despite conscientious hospital and home care techniques for maintaining tunneled catheters, there remains a significant risk of catheter
FIGURE 2. Tunneled central venous catheters (Reprinted with permission from Bard Access Systems, Salt Lake
City, tIT).
FIGURE 3. Implanted infusions port (Reprinted with permission from Bard Access Systems, Salt Lake City, UT).
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with the use of transcutaneous or subcutaneous anesthetics. Young patients may continue to exhibit aversive reactions to the needle stick associated with port accession, but most patients report that it is much less traumatic than venipuncture. Once the port needle is in place and secured with an occlusive dressing, it can be used much like an external catheter for infusion of medications, fluids, and blood products, and for blood sampling, without additional painful sticks. The port needle can also be used as a heparin lock by placing an injection cap on the end of a noncoring needle with an extension set. When used as a heparin lock, it should be flushed in accordance with institutional guidelines for central venous catheters. When not in use, the port requires flushing with a heparinized solution approximately every 4 weeks. ~11 infusion ports require the use of noncoring needles, either straight or 90° angle needle with extension set. The port is accessed by injecting the needle perpendicular to the skin for entry into the device (ie, in the same manner as an intramuscular injection). In addition, several manufacturers produce a port constructed in such a way that the noncoring needle should be inserted parallel to the skin (ie, the same manner in which an 1~ catheter is placed). It is essential that caregivers know which type of device the patient has in order to place the needle correctly. Limitations of this type of device include the trauma associated with needle sticks, which may make it an inappropriate choice for the needlephobic patient whose medical regimen requires frequent access to the central circulation. Also, there is a significant risk of needle dislodgement from the port during continuous infusions, resulting in subcutaneous infiltration of drug or fluids. This can be particulariy harmful for patients receiving vesicant drugs or parenteral nutrition. Because the port is completely implanted, troubleshooting problems such as occlusion or infection may be more difficult. Removal of the port, a procedure that requires general anesthesia, is more extensive than removal of an external catheter. As with external catheters, infection is a potential complication. infections related to implanted ports can manifest either as soft tissue infection within the subcutaneous pocket where the port is secured or as sepsis. Several studies have compared infection rates in implanted
ports with externalized tunneled catheters. Ross
reported that infection occurred less frequently in implanted ports than in externalized catheters in children with cancer. Mirro et al et al
found that ports had a lower rate of infection than catheters overall, but this difference was not significant when subjects were matched for age and clinical characteristics.8 A study by Wurzel et al comparing infection rates of BroviacHickman catheters and implantable venous devices in pediatric oncoiogy patients showed no significant differ ence in infection rate.9 lt remains to be seen whether the increased use of implanted ports in medically compromised patients will result in an infection rate similar to that seen with the use of tunneled catheters.
Peripherally Inserted
Central Catheters
Because some long-term patients are not candidates for centrally inserted catheters, alternatives to traditional peripheral 1’~ lines have been developed. Peripherally inserted central catheters (PICCs) are used primarily with patients in the home care setting who require prolonged courses of antimicrobial therapy and in intensive care settings (Fig 4). PICCs have had limited use with pediatric oncology patients, but they may be appropriate for children who do not have centrally established devices that need more frequent or continuous peripheral access. For example, in the care of the terminally ill child who is not a candidate for anesthesia for placement of a tunneled catheter,
FIGURE 4.
Peripherally inserted central catheter (pict) (Reprinted permission from Bard Access Systems, Salt Lake
City,, UT).
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the PICC could offer a parenteral route for symptom management at home. These polyurethane or Silastic catheters are placed, preferably with local anesthesia, through the antecubital fossa into either the basilic or cephalic vein and threaded into the subclavian vein or SVC. The catheter is secured with an occlusive dressing and may remain in place for up to 3 months.10 Because PICC lines have not been in use for an
extended
period of time, complication
rates
have not been established. Some discomfort and limitation of mobility may be associated with line placement in the antecubital fossa.
Complications Associated With VAL7s Complications of VADs fall into six major categories : infection, cutaneous reactions, occlusion, catheter misplacement, SVC syndrome, air embolism, and catheter breakage. Nursing management of patients with VADs requires the understanding of these complications and the use of appropriate interventions to prevent or manage them. Infection can result from contamination of (1) the catheter during placement, (2) the infusion system during use, or (3) the catheter exit site. Risk of contamination during placement is reduced with appropriate use of sterile technique either in the operating room or at the bedside. Hayward identified two additional factors associated with insertion-related infection: neutropenia or fever >101°F on the day of catheter in-
sertion.6 More commonly, the VAD becomes colonized by bacteria either at the exit site or through the infusion system. Studies of institutional incidence of central line infection are difficult to compare because of differences in patient populations, duration of catheter use, types of cath-
used, surgical techniques, dressing change protocols, and data collection procedures. Rates of infection have been reported to range from 25% to 55% .7-9,11-15 In a study of central line infections in pediatric cancer patients, Johnson reported a low incidence of catheter-related septic episodes per catheter use days, but almost 50% of the patients in the study had at least one episode of catheter infection. 15 Infection in the immunocompromised patient can be life-threatening eters
and may necessitate VAD removal. The timely initiation of broad-spectrum antimicrobial agents in the febrile, neutropenic patient has become standard in pediatric oncology practice and has greatly reduced the risk of overwhelming sepsis; thus, VADs are not usually removed at the first sign of fever. There is a growing body of literature that supports treating VAD-related infections with topical and/or intravenous antimicrobials in an attempt to clear the infection without removal of the device. Reports of successfully treated VAD infection without removal range from 38% to 89%.~’~-~ Several studies have compared skin cleansing technique with dressing change protocols and their effect on the incidence of exit site infections in patients with catheters. Most of these studies show no difference between various antiseptic techniques or between gauze dressing and transparent dressings.’ &dquo;,’9 In addition, in a comparison of two brands of transparent dressing, gauze dressing, and no dressing at all, Petrosino et al found no difference in infection rates between the four groups.’ 9 Bagnall-Reeb and Ruccione, in a retrospective study, describe the treatment of local staphylococcus wound infections with Neosporin (Burroughs-Wellcome Company, Research Triangle Park, NC) or Bactroban (Beechum Laboratories, Bristol, TN) and local yeast infections with Mycostatin or Mycolog ointment (ER Squibb & Sons, Inc, Princeton, NJ). Of 13 exit site infections treated topically, only 3 failed to respond and required IV antibiotic therapy. Two of the three eventually required catheter removal. 20 Although many local and systemic infections will resolve with treatment, some will still require catheter removal. Indications for removing an infected VAD include the presence of large numbers of bacterial colonies isolated from blood cultures as well as evidence of soft tissue infection, such as exudate and/or erythema 11.16,21 that are not responsive to topical or systemic therapy. Decker and Edwards, in a review of the infectious disease literature, describe how blood cultures drawn both centrally and peripherally with a ratio of bacteria five times greater in the central than peripheral circulation are unlikely to be sources of infection other than the catheter. 22 Most institutions use some form of occlusive
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.
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exit site of tunneled catheters. Cutaneous reactions to dressing materials and solutions occur in some patients. These reactions can range from mild to severe and may predispose the patient to local infection and significant discomfort. Nursing management for these problems is well described in BagnallReeb and Ruccione. 20 Total or partial catheter occlusion is the second most common problem associated with VADs. Occlusion can result either from drug precipitation or from formation of a fibrin clot within the lumen of the catheter. Drug precipitation can occur when incompatible solutions or drugs are given simultaneously or without proper clearing of the line between administration of medications. This type of occlusion does not resolve with the use of fibrinolytic agents, is very difficult to clear, and may necessitate the removal of the catheter. Shulman et al describe safely using 0.2 to 1.0 mL of 0.1 N (normal) hydrochloric acid to clear drug precipitates in four occluded central venous catheters that did not clear with fibrinolytics 23 Patency was restored after leaving the solution in the catheter for several hours. Occasionally clinicians have had success clearing drug precipitates with the infusion of fluids without additives, such as normal saline or D5W at a rate of 20 to 40 mL. Formation of clots within the lumen of the catheter can usually be avoided by the careful and regular use of flushing solutions after infusions or blood drawing. The Groshong catheter (CR Bard, Inc, Cranston, RI) requires only saline flush to maintain patency, however there is a lack of consensus regarding flush solutions required for other VADs. Most institutions use heparinized saline in concentrations ranging from 10 pfmL to 1,000 wlmL to maintain patency in intermittently accessed lines or ports, although some institutions advocate saline-only flushing. Different regimens used include flushing every 12 hours, daily, or weekly. In a recent study comparing heparin I O p/mL twice a day with weekly 9-ml flush of isotonic saline, no difference in clot formation was found. 24 Therefore, the use of low-dose heparin or saline may therefore be
dressing over the
.
preferable to introduce less systemic heparin. Even with appropriate flushing of catheters, fibrin clots can form at the tip of the catheter,
causing either partial or total catheter occlusion. Fibrin sheaths can form around the outside of the catheter creating outflow obstruction. In this situation, fluids can be infused, but blood cannot be withdrawn. Sometimes this condition can be alleviated by repositioning the patient, having the patient perform a Valsalva maneuver, or administering 10 mL or more of saline before blood withdrawal. When these strategies are ineffective, fibrinolytic agents can be used to remove the fibrin that is obstructing blood withdrawal. Likewise, if the lumen or tip of a catheter becomes completely occluded with a blood clot such that fluid cannot be administered nor blood withdrawn, patency can usually be restored with the use of a fibrinolytic agent. Urokinase is currently recommended over streptokinase because of the reduced incidence of antigenic reaction.25 Preliminary data document the safe use of tissue plasminogen activator for clearing occluded catheters that do not respond to
fibrinolytics.26
The urokinase product literature describes the procedure for declotting catheters with a fibrinolytic agent To determine the appropriate volume of urokinase to instill per catheter, first determine the size and brand of catheter and refer to the manufacturer’s recommended priming volume. If this information is not available, the priming volume can be estimated by determining the amount of fluid or vacuum measured when a syringe plunger is pulled back withdrawing the contents of the catheter before obtaining blood return. The half-life of fibrinolytic agents is in the range of 10 to 60 minutes, allowing for repeated administrations in an attempt to restore catheter patency. Brown et al report experience with adults in administration of four separate doses within a 24-hour period and up to three doses in 4 hours without systemic effects. For thrombocount
