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Central Venous Catheter Practices: Results of a Survey
Central Venous Catheter Practices: Results of a Survey Mark A. Clemence, MD Diane Walker, RN, MSN, DCN Barry M. Farr, MD, MSc
Approximately 5 million central venous catheters (CVes) of various types are sold in the United States each year. 1 Many of these catheters are inserted in hos.. pitalized patients on a short.. term basis for hemody.. namic monitoring or administration of drugs, parenteral nutrition, fluid therapy, and blood products. Long.. term, tunneled CVCs and implantable ports are inserted for ease of venous access in patients with malignancy or other serious diseases requiring prolonged courses of in.. fusion therapy. These catheters are often maintained by the patient on an outpatient basis, with the help of a visiting nurse from a home health agency. Complications of CVCs include occlusion, throm.. bophlebitis, and infection, each of which may lead to ex.. tra hospital costs. The incidence of primary nosocomial bloodstream infections has increased twofold to threefold in the past decade. 2 The relative frequencies of staphylo.. cocci, Candida species, and Enterococcus species among the etiologic agents of these infections have increased sig.. nificantly. CVCs now account for 90% of all catheter.. re.. lated bloodstream infections. 3
Numerous published studies have focused on risk factors for catheter complications and methods of pre.. venting them. Many of these publications have con.. cluded with recommendations for clinical practice, but little information is available regarding the frequency with which such practices are implemented. We conducted a survey of clinicians responsible for CVC maintenance in both hospital and outpatient set.. tings to assess frequencies of practices being employed today in the maintenance of CVCs for the prevention of complications and in the documentation of blood.. stream infection; the most important infectious compli.. cation of CVCs.
Methods A questionnaire was distributed to a convenience sample of persons attending the annual conference of the Na.. tional Association of Vascular Access Networks, held in New Orleans on September 24 through 26, 1992. The
Mark A. Clemence, MD, is a board certified Infectious Disease Physician in private practice at St. Luke's Hospital and Medical Center in Milwaukee, Wisconsin. Dr. Clemence is also a Clinical Instructor with a residency program at The Medical College of Wisconsin.
Diane Walker, RN is a registered nurse at the University of Virginia Health Sciences Center and specializes in oncology nursing. Barry M. Farr, MD, MSc, is the Hospital Epidemiologist at the University of Virginia Hospital. He is also Associate Professor of Internal Medicine at the University of Virginia School of Medicine where he is also Director of the Epidemiology Program. Reproduced from Clemence MA, Walker 0, Farr, BM. Central venous catheter practices: Results of a survey. American Journal of Infectious Control 1994; 23:5-12. With permission from Mosby-Year Book, Inc.
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Frequencies of catheter dressing types
TABLE 1
Type of dressing Transparent Gauze totally covered by tape Gauze not totally covered by tape
TABLE 2
Teaching Hospital
Nonteaching Hospital
Home Health Agency
No. 19/23 5/23 4/23
No. 17/21 7/21 1/21
No. 45/48 4/48 4/48
%
83 22 17
81 33 5
%
94 8 8
Frequencies of catheter dressing changes
Twice daily Once daily Three times per week Twice weekly Once weekly
Teaching Hospital
N onteaching Hospital
Home Health Agency
No. 0/19 1/19 11/19 4/19 3/19
No. 0/19 1/19 7/19 6/19 5/19
No. 1/46 3/46 20/46 4/46 18/46
%
0 5 58 21 16
survey consisted of 15 questions related to specific prac, tices in the maintenance of CVCs. Questions in the sur, vey focused on infection control measures, methods for maintaining catheter patency, and the collection of blood samples from the catheter for diagnostic tests, in' cluding blood cultures.
Results Ninety,three (44%) of the 212 persons attending the conference completed the questionnaire. Most respon, dents were nurses affiliated with hospitals or home health agencies. Twenty,one of the respondents (23%) represented teaching hospitals, 23 (25%) represented nonteaching hospitals, and 48 (52%) represented home health agencies. Twenty,four states were represented by respondents to the survey, with 12 respondents (13%) from the northeast, 24 (26%) from the southeast, 16 (1 7%) from the Midwest, and 41 (44%) from the west, including three from Alaska and one from Hawaii.
Infection Control Measures Dressings. Transparent dressings were used by most respondents from all types of institution, as indi, cated in Table 1. Cotton gauze dressings were used by only a minority of the respondents. Clean technique was
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%
0 5 37 32 26
%
2 7 43 9 39
used for dressing changes by 17% (4/23) of respondents from teaching hospitals, 19% (4/21) from nonteaching hospitals, and 77% (37/48) from home health agencies. Dressing Changes. Most respondents indicated that CVC dressings were changed three times per week on average. There was considerable variation, as indicated in Table 2. Sterile technique was used for dressing changes by 87% of respondents from teaching hospitals (20/23), 90% (19/21) from nonteaching hospitals, and 77% (37/ 48) from home health agencies. Masks were used in the hospital for dressing changes by 52% of teaching hospital respondents (12/23) and 67% of those from nonteaching hospitals (14/21). Masks were recommended for dressing changes at home by 22% (5/23) of the respondents from teaching hospitals, 38% (8/21) from nonteaching hospitals, and 40% (19/48) from home health agencies. Antiseptics and Antimicrobial Ointments. Alcohol and povidone,iodine solutions were the antiseptics most frequently used for skin preparation at the time of dress' ing changes, as indicated in Table 3. Antimicrobial oint, ment was used for dressing changes by 43% of those from teaching hospitals (10/23),76% (16/21) fromnonteach, ing hospitals, and 33% of those from home health agen,
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TABLE 3 Frequencies of antiseptic use for dressing changes Teaching Hospital
Alcohol Povidone.. iodine Hydrogen peroxide Chlorhexidine
N onteaching Hospital
Home Health Agency
No.
%
No.
%
No.
%
18/23 22/23 6/23 3/23
78 96 26 13
15/21 21/21 6/21 1/21
71 100 29 5
46/48 45/48 5/48 2/48
96 100 10 4
TABLE 4 Frequency of flushes for tunneled catheters Teaching Hospital
As needed Three times daily Twice daily Daily Three times weekly Twice weekly Once weekly Once monthly
Nonteaching Hospital
No.
%
No.
0/19 2/19 2/19 10/19 2/19 2/19 1/19 0/19
0 11 11 53 11 11 5 0
1/19 2/19 0/19 10/19 1/19 0/19 3/19 0/19
Home Health Agency
%
5 11 0 53 5 0 16 0
No.
%
0/42 0/42 2/42 29/42 3/42 0/42 7/42 1/42
0 0 5 69 7 0 17 2
TABLE 5 Frequency of flushes for implantable ports Teaching Hospital
As needed Three times a day Twice daily Once daily Once weekly Once monthly
No.
%
No.
0/19 2/19 1/19 1/19 0/19 15/19
0 11 5 5 0 79
1/19 0/19 1/19 2/19 0/19 13/19
cies (16/48). Among those who used antimicrobial oint.. ment, povidone..iodine was used by 100% of those from teaching hospitals (10/10), 81 % of those from nonteach.. ing hospitals (13/16), and 81 % of those from home health agencies (13/16). Polymyxin..neomycin..bacitracin ointment was used by 10% (1/10) from teaching hospitals, 81 % (13/16) from nonteaching hospitals, and 50% of those representing home health agencies (8/16). No re.. spondents indicated that mupirocin ointment was used for dressing changes.
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Nonteaching Hospital
Home Health Agency
No.
%
5
0/43 0/43 0/43 1/43 5/43 37/43
o 5 11
o 68
%
o o o 2
12 86
Measures to Maintain Catheter Patency Heparin flushes were used to maintain the patency of noninfusing CVCs (excluding Groshong catheters) by 96% (22/23) from teaching hospitals, 95% (20/21 from nonteaching hospitals, and 98% of those representing home health agencies (47/48). Saline solution flushes without heparin were used by 9% (2/23) from teaching hospitals, 10% (2/21) from nonteaching hospitals, and 25% (12/48) from home health agencies.
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TABLE 6
Frequency distribution of the amount of blood withdrawn from catheter before diagnostic specimen collection Teaching Hospital
N onteaching Hospital
Home Health Agency
Amount (ml)
No.
%
No.
%
No.
%
<5 5-9
6/23 16/23 1/23
26 70 4
8/20 9/20 3/20
40 45 15
8/46 34/46 4/46
17 74 9
~10
The most commonly used concentration of heparin to maintain noninfusing CVCs was 100 units/ml (77% of respondents from teaching hospitals [17/22],70% from nonteaching hospitals [14/20], and 87% [41/47] from home health agencies). A concentration of 10 units/ml was used by 320/0 of those from teaching institu, tions (7/22), 40% (8/20) from nonteaching hospitals, and 19% (9/47) from home health agencies. Frequencies of flushes used for tunneled catheters and for implantable ports are indicated in Tables 4 and 5, respectively.
Aspiration of Blood for Diagnostic Tests Personnel responsible for routinely drawing blood samples from CVCs in teaching hospitals included nurses (96% [22/23]) physicians (26% [6/23/cb), laboratory personnel (4% [1/23]), and medical students (9% [2/23]). In non, teaching hospitals, nurses (100% [21/21]) and physicians (10% [2/21]) drew the blood. Respondents from home health agencies indicated that blood samples were drawn from CVCs by nurses (79% [38/48]) and physicians (6% [3/48]). Blood cultures were drawn from CVCs by 87% of respondents from teaching hospitals (20/23), 71 % of respondents from nonteaching hospitals (15/21), and 83 % of those from home health agencies (40/48). Of those who used CVCs to draw blood cultures, periph, eral cultures were drawn as well by 95% of those repre, senting teaching hospitals (19/20), 100% of those from nonteaching hospitals (15/15), and 98% of those from home health agencies (39/40). Quantitative blood cultures were performed by those accessing CVCs for blood cultures by 50% of re, spondents representing teaching hospitals (10/20), 33% of those from nonteaching hospitals (5/15), and 23% of those from home health agencies (9/40). Masks were used when drawing blood samples by 22% (5/23) from teaching hospitals, 19% (4/21) from
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nonteaching hospitals, and 8% (4/48) from home health agencies. Catheter ports were disinfected with alcohol before accessing CVCs by 83% of respondents from teaching hospitals (19/23), 71 % of those from nonteaching hospi, tals (15/21), and 90% of those from home health agencies (43/48). Povidone, iodine disinfection was used before accessing CVCs by 48% of respondents from teaching hospitals (11/23), 62% of respondents from nonteaching hospitals (13/21), and 52% of those from home health agencies (25/48). Both alcohol and povidone,iodine were used for disinfecting ports before accessing CVCs by 35% of respondents from teaching hospitals (8/23),33% of those from nonteaching hospitals (7/21), and 42% of those from home health agencies (20/48). Blood samples were not drawn from CVCs for cer, tain laboratory tests. Fifty,seven percent of respondents from teaching hospitals (13/23) did not draw blood from CVCs for the following reasons: antibiotic levels only (one), cyclosporine levels (two), coagulation levels only (nine), and an unspecified reason (one). Forty,three per' cent of respondents from nonteaching hospitals (9/21) did not draw blood from CVCs for the following reasons: antibiotic levels only (one), antibiotic levels and serum bactericidal levels (one), antibiotic levels and coagula, tion profiles (two), coagulation profiles only (three), and an unspecified reason (two). Sixty,five percent of re, spondents from home health agencies (31/48) did not draw blood from CVCs for the following reasons: antibi, otic levels only (10), antibiotic levels and coagulation profiles (five), coagulation profiles only (14), and an un, specified reason (two). The amount of blood withdrawn from CVCs before collection of specimens for laboratory tests is indicated in Table 6. In all but one case (one respondent from a teaching institution), the blood was discarded rather than returned to the patient after the specimen was collected.
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Discussion This study describes practices being employed for the prevention of complications related to CVCs by hospi, tals and home health agencies, as represented by respon, dents to our survey, throughout the United States today.
Infection Control Practices Multiple studies have examined the risk factors for in' fection associated with CVCs. Most have focused on short'term CVCs in hospitalized patients, however, and relatively little information is available regarding modi, fiable risk factors for infection with long,term tunneled CVCs.
Dressing Changes Transparent dressings were the most frequent type of CVC dressing used within each group. Several recent studies have demonstrated an increase in infectious corn, plications associated with the use of transparent dress' ings. 4'7 A recent metaanalysis of previously published studies demonstrated a statistically significantly in' creased risk of catheter tip colonization for catheters covered with transparent dressings, as compared with dressings consisting of cotton gauze covered by tape, and a concomitant trend toward an increased risk of cath, eter,related bacteremia. 8 In one study,9 bacterial skin colonization was significantly greater under conven, tional transparent dressings left on for a week than under gauze dressings changed every other day. Greater rates of skin colonization associated with some types of transpar, ent dressings may be caused by differences in moisture vapor permeability, oxygen transmission, or cutaneous adherence. I Disadvantages of transparent dressings in' clude poor adhesion when used with topical ointments, patient distress at the sight of the catheter insertion site, and greater expense.I,IO One studyll reported a signifi, cantly greater risk of unspecified catheter malfunction with transparent dressings than with dry, sterile gauze. The most recent randomized trial comparing gauze with transparent dressings l2 found no difference in infection or colonization rates. Consistent findings from additional studies are needed, however, to reverse the impression that transparent dressings are associated with an in, creased risk with short,term catheters. Two studies of
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transparent dressings on tunneled CVCs 9,13 found no in, crease in the risk of infection. After weeks of healing and tissue infiltration around the catheter cuff, the risk of in' fection decreases considerably, and transparent dressings may not significantly alter the acceptably low rates of in, fection observed with tunneled catheters. Some institu, tions do not even recommend dressings for such healed catheter sites and use only an adhesive strip bandage or a piece of paper tape to help secure the catheter to the chest. 14 Dressings were changed three times per week by most respondents. In 1982, the Centers for Disease Con, trol 15 published its guidelines for the care of intravascular catheters. These recommendations, which were not based on the results of randomized trials, stipulated that dressings should be inspected by palpation at least every 24 hours. A large, randomized trial 16 showed no differ, ence in infection rates when dressings for peripheral in' travenous catheters were changed every 2 days rather than being changed as clinically indicated. Maki l has recommended that dressings used on CVCs in patients in the intensive care unit be changed every other day. More than half of the respondents representing both teaching and nonteaching hospitals indicated that masks were used for dressing changes while the patient was in the hospital. Conversely, most did not use masks for dressing changes at home. No data are available to document the benefit of this practice.
Antiseptics Nearly all respondents in each category indicated that povidone,iodine was used as a skin antiseptic for dress' ing changes, and most respondents in each category in' dicated that 70% alcohol was also used. A recent clinical trial assessing peripheral blood culture contami, nation rates l7 demonstrated significantly less contami, nation with tincture of iodine than with iodophor (6.25% contamination for iodophor vs. 3.74% for tinc, ture of iodine, p < 0.00001), suggesting superior anti, septic properties for tincture of iodine compared with povidone,iodine. Although tincture of iodine (1 % to 2%) may be slightly more effective than 70% alcohol or iodophors, the latter two preparations have been associ, ated with a lower incidence of local adverse reactions. 18 Hexachlorophene and benzalkonium compounds should not be used as skin preparations for catheter dressings
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because of an increased risk of infectious complications with Pseudomonas and Enterobacter species. 19 Maki and coworkers 20 recently demonstrated superior efficacy of a 2% solution of chlorhexidine glu.. conate for skin antisepsis with dressing changes for short.. term CVCs compared with 70% alcohol or 10% povidone.. iodine (2.3 local catheter.. related infections/ 100 catheter days vs 7.1 and 9.3 for alcohol and povidone.. iodine, respectively; p = 0.02). Although some of the respondents indicated that chlorhexidine was used as an antiseptic, no commercial formulation was available for use as an antiseptic for catheter dress.. ing changes at the time of the survey. Three fourths of respondents from nonteaching hospitals indicated that antimicrobial ointment was used for dressing changes, whereas fewer than half of the respondents from teaching hospitals and home health agencies indicated that they used such ointment. Povidone.. iodine ointment was shown to significantly reduce the risk of subclavian dialysis catheter.. related bloodstream infections in a recent randomized, con.. trolled trial,21 but six (14%) of the 42 hospitals and agencies in this survey that used ointment did not use povidone . . iodine ointment. Polymyxin.. neosporin.. bacitracin ointment, which was used by 11 (26%) of the 42 respondents who used ointment, has been dem.. onstrated to halve the risk of bacterial colonization of catheters but also to increase the risk of Candida coloni.. zation five times. 22 Several studies 23,25 have reported an increase in catheter.. related bloodstream infections by Candida species, which may be associated with consid.. erable morbidity and mortality. For this reason, Flowers and associates 22 recommended against the use of poly.. myxin.. neomycin.. bacitracin ointment on CVCs. This concern may be more important early after placement of long.. term tunneled catheters than later, after the catheter site has healed, because catheter infection may be more likely to occur by the intraluminal route after prolonged catheterization.
Flushing The overwhelming majority of respondents in all three categories indicated that heparin was used to maintain patency of noninfusing CVCs. Early studies 26,28 demon.. strated that the addition of heparin to intravenous solu.. tions diminished the incidence of infusion phlebitis.
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These studies involved continuous infusions; the ben.. efit of heparin in preventing phlebitis in noninfusing CVCs is less certain. Various flushing protocols for maintenance of CVCs have been developed and adopted by individual institu.. tions; however, no consensus has been established. 29 In 1985, Gillies and associates 3o found that flushing Hickman catheters with normal saline solution only did not increase the complication rate. Several studies,31,34 including two metaanalyses, similarly demonstrated that saline solution may be as effective as heparin in main.. taining patency and preventing thrombophlebitis. The small doses of heparin used to flush vascular catheters are not without risk; adverse reactions, such as bleeding complications, have been reported. 34 In addition, there is a potential for interaction of heparin with other drugs if the catheter is not properly flushed with saline solution before use. Estimated annual savings to individual hospi.. tals from discontinuing heparin flushes have ranged from $10,000 to $60,000. 35 '38 There was considerable variation among respon.. dents regarding the frequency of flushing, with most re.. spondents indicating daily flushes for tunneled catheters and monthly flushes for implantable ports. Hickman and Broviac catheters are generally flushed every 12 to 24 hours while the patient is in the hospital and daily or ev.. ery other day while the patient is at home. 14 Two recent prospective studies 29,32 demonstrated no significant dif.. ference in CVC complications after switching from daily or twice daily flushing to a weekly flushing regimen with saline solution. Implantable ports are usually flushed with heparin every 4 weeks, but no controlled studies are available regarding this practice.
Blood Collection from Indwelling Catheters for Blood Cultures Blood cultures were drawn through indwelling catheters by most respondents in each category. In recent stud.. ies,39,40 such qualitative blood cultures aspirated from indwelling catheters were associated with a higher rate of false . . positive cultures than that for specimens drawn from peripheral veins. Most respondents also drew qualitative cultures from a peripheral vein, but many clinicians tend to treat positive blood culture results as indicating bacteremia even if results of all peripheral cultures are negative.
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Quantitative blood cultures were used by one half of the respondents representing teaching institutions, one third of those at nonteaching hospitals, and fewer than one fourth of those from the home health agencies. The use of quantitative blood cultures was first described in 1979, when Wing and associates 41 suggested that blood drawn through an infected venous catheter should result in higher quantitative colony counts than found with blood drawn from a peripheral vein. Bacteremia caused by experimentally induced bacterial peritonitis in a rabbit model also resulted in higher bacterial concentrations in blood aspirated from a CVC than in blood from a periph.. eral vein, presumably because the liver, spleen, and lung act as filters for bacteria. 42 The ratio of concentrations never exceeded 4: 1 in this animal model, so the investi.. gators suggested that the ratio of bacterial colonies in blood drawn through a CVC compared with blood from a peripheral vein should be greater than 5:1 with catheter.. related bacteremia. 42 Catheter infection itself, however, was not studied in the model. Four studies 43-46 tested this hypothesis in patients with suspected infection by using direct catheter segment cultures, the standard method of the past two decades, as a "gold standard." The test per.. formance of paired quantitative blood cultures varied widely in these studies. The use of quantitative cultures cannot be routinely recommended until more consis.. tently accurate results are achieved in such studies. Removal of a short.. term CVC from a patient with suspected catheter infection may be helpful in several ways: (1 )by allowing culture of catheter segments for diagnosis, (2) by removing a foreign body from the site of infection and thus promoting a faster cure than with antibiotic therapy alone, and (3) by preventing recur.. rence of bacteremia after completion of antibiotic therapy.47 The principal disadvantage of removing the catheter for culture is the unnecessary cost of the re.. placement catheter, of radiographs required to confirm tip position, and of clinicians' time to do these proce.. dures for the many cases in which the catheter is not the source of infection. 48 ,49 With tunneled catheters, cli.. nicians are unlikely to remove the catheter immediately even if results of paired quantitative blood cultures are positive. They usually prefer to treat the bacteremia with antibiotics and leave the catheter in place if the patient's condition responds, as occurs with most bacteremias in such patients. Further studies of the ac.. curacy and cost.. effectiveness of paired quantitative blood cultures are needed.
36
Conclusion The results of this survey reflect practices in use today for the maintenance of CVCs, although respondents to a survey at a national conference on venous.. access devices may not be representative of caregivers at all health care facilities. Considerable variation existed within but not between the various types of health care organizations represented in the survey. The increasing acuity of illness among hospitalized patients and the increasingly fre . . quent use of CVCs may largely explain the increasing incidence of nosocomial bloodstream infection observed during the past decade, but some of the practices docu.. mented in this survey may also have contributed. The high frequency of use of transparent dressings, for ex.. ample, may have contributed to the observed increase in the overall rate of infection. The use of polymyxin.. neomycin.. bacitracin ointment on CVCs may have con.. tributed to the increased rate of Candida infection. The increasing use during the past decade of qualitative blood cultures aspirated from indwelling catheters may have resulted in an increased rate of pseudobacteremia; such cases are counted as bloodstream infections according to Centers for Disease Control and Prevention definitions if the physician chooses to treat the patient with antibi.. otics because of the positive blood culture. We wish to thank Donna C. McGraw for technical assistance in preparing this article.
References 1. Maki D. Infections due to infusion therapy. In: Bennett JV, Brachman PS, eds. Hospital infections. Boston: Little, Brown, 1992:849. 2. Banerjee SN, Emori TG, Culver OH, et al. Secular trends in nosocomial primary bloodstream infections in the United States, 1980-1989. Am J Med 1991:91 (SuppI3B):87S-9S. 3. Maki DG. Nosocomial bloodstream infections [Abstract 3]. In: Proceedings of the third decennial international conference on nosocomial infections. Atlanta: Centers for Disease Control and the National Foundation for Infectious Diseases, 1990. 4. Conly J, Grieves K, Peters B. A prospective, randomized study comparing transparent and dry gauze dressings for central venous catheters. J Infect Dis 1989;159:310-9. 5. Katich M, Band J. Local infection of the intravenous,cannulae wound associated with transparent dressings. J Infect Dis 1985; 151 :971-2. 6. Powell C, Regan C, Fabri P, Ruberg R. Evaluation of Opsite catheter dressings for parenteral nutrition: a prospective ran, domized study. JPEN J Parenter Enter Nutr 1982;6:43-6.
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7. Craven D, Lichtenberg D, Kunches M, et al. A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites. Infect Control 1985;6:361-6. 8. Hoffman K, Weber D, Samsa G, Rutala W. Transparent poly.. urethane film as an intravenous catheter dressing: a meta.. analysis of the infection risks. JAMA 1992;267:2072-6. 9. Maki DG, Will L. Colonization and infection associated with transparent dressings for central venous, arterial, and Hickman catheters: a comparative trial [Abstract 991]. In: .Program and . abstracts of the 24th interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1984. 10. Hampton A, Sherertz R. Vascular..access infections in hospi.. talized patients. Surg Clin N Am 1989;68:57-7l. 1l. Gantz N, Presswood G, Goldberg R, Doem G. Effects of dress.. ing type and change interval on intravenous therapy compli.. cation rates. Diagn Microbiol Infect. Dis 1984;2:325-32. 12. Maki DO, Stolz SM, Wheeler SJ, Mermel LA. A prospective, randomized, three..way clinical comparison of a novel highly permeable polyurethane dressing with 442 Swan..Ganz cath.. eters [Abstract 825]. In: Programs and abstracts of the 32nd interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiol.. ogy, 1992. 13. Shivnan JC, McGuire D, Freedman S, et al. Comparison of transparent adherent and dry sterile gauze dressings for long.. term central catheters in patients undergoing bone marrow transplant. Oncol Nurs Forum 1991;18:1349-56. 14. Lucas A. A critical review of venous access devices: the nurs.. ing perspective. Curr Issues Cancer Nurs Pract 1993;1:1-10. 15. Simmons B, Hooton T, Wong E, AlIen J. Guidelines for preven.. tion of intravascular infections. Intravasc Infect 1981;3:62-79. 16. Maki DG, Ringer M. Evaluation of dressing regimens for pre.. vention of infection with peripheral intravenous catheters. JAMA 1987;258:2396-403. 17. Strand C, Wajsbort R, Sturman K. Effect of iodophor vs iodine tincture skin preparation on blood culture contamination rate. JAMA 1993;269:1004-6. 18. Decker M, Edwards K. Central venous catheter infections. Pe.. diatric Clin N Am 1988;35:579-612. 19. Maki D, Goldmann D, Rhame F. Infection control in intrave.. nous therapy. Ann Intern Med 1973;79:867-87. 20. Maki D, Ringer M, Alvarado C. Prospective randomized trial of povidone..iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial cath.. eters. Lancet 1991;338:339-43. 2l. Levin A, Mason A, Jindal K, et al. The value of topical povidone.. iodine (PV.. I) ointment in the prevention of hemodialysis related sepsis [Abstract 1078]. In: Programs and abstracts of the 29th interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiology, 1989. 22. Flowers R, Schwenzer R, Kople R, Fisch M, Tucker S, Farr B. Ef.. ficacy of an attachable subcutaneous cuff for the prevention of intravascular catheter..related infections. JAMA 1989;261:87883. 23. Zinner S, Denney..Brown B, Braun P, Burke J, Toala P, Kass E.
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24.
25.
26.
27.
28. 29.
30.
3l.
32.
33.
34.
35.
36. 37. 38. 39.
40.
4l.
42.
Risk of infection with intravenous indwelling catheters: effect of application of antibiotic ointment. J Infect Dis 1969; 120: 616..9. Maki D, Band J. A comparative study of polyantibiotic and iodophor ointments in prevention of vascular catheter..related infection. Am J Med 1981;70:739-44. Norden C. Application of antibiotic ointment to the site of venous catheterization: a controlled trial. J Infect Dis 1969; 120:611-5. Tanner W, Delaney P, Hennessey T. The influence of heparin on intravenous infusions: a prospective study. Br J Surg 1980; 67:311-2. Bailey MJ. Reduction of catheter..associated sepsis in parent.. eral nutrition using low..dose intravenous heparin. BMJ 1979; 1:1671-3. Daniell H. Heparin in the prevention of infusion phlebitis: a double..blind controlled study. JAMA 1973;226:1317-2l. Kelly K, Dumenko L, McGregor S, McHutchion M. A change in flushing protocols of central venous catheters. Oncol Nurs Forum 1992;19:599-605. Gillies H, Rogers HJ, Johnston J, Harper PG, Rudge CJ. Is re.. peated flushing of Hickman catheters necessary? BMJ 1985; 290:1708. Weightman N, Simpson E, Speller D, Mott M, Oakhill A. Bacteremia related to indwelling central venous catheters: prevention, diagnosis, and treatment. Eur J Clin Microbiol In.. fect Dis 1988;7:125-9. Smith S, Dawson S, Hennessey R, Andrew M. Maintenance of the patency of indwelling central venous catheters: is hep.. arin necessary? Am J Pediatr Hematol Oncol1991;13:141-3. Peterson F, Kirchoff K. Analysis of the research about heparin.. ized versus nonheparinized intravascular lines. Heart Lung 1991;20:631-42. Goode C, Titler M, Rakel B, Ones D. A meta..analysis of ef.. fects of heparin flush and saline flush: quality and cost impli.. cations. Nurs Res 1991;40:324-30. Taylor N, Hutchison E, Milliken W, Larson E. Comparison of normal versus heparinized saline for flushing infusion devices. J Nurs Qual Assur 1989;3:49-55. Swerling R. Normal saline or dilute heparin for heparin lock flush? Infusion 1982;6:123-4. Dunn D, Lenihan S. The case for the saline flush. Am J Nurs 1987;87:798-9. Cyganski J, Donahue J, Heaton J. The case for the heparin flush. Am J Nurs 1987;87:796-7. Bryant JK, Strand CL. Reliability of blood cultures collected from intravascular catheter versus venipuncture. Am J Clin Pathol1987;88:113-6. Bates DW, Goldman K, Lee TH. Contaminant blood cultures and resource utilization: the true consequences of false..positive results. JAMA 1991;265:365-9. Wing E, Norden C, Shadduck R, Winkelstein A. Use of quan.. titative bacteriologic techniques to diagnose catheter..related sepsis. Arch Intern Med 1979;139:482-3. Flynn P, Shenep J, Stokes D, et al. In situ management of con.. firmed central venous catheter..related bacteremia. Pediatr In.. fect Dis J 1987;6:729-34.
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43. Douard MC, Marie 0, Clementi E, et al. Does a negative cath.. eter tip culture exclude the diagnosis of catheter..related bact.. eremia? [Abstract 455] In: Programs and abstracts of the 31 st interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiology, 1991. 44. Paya CV, Guerra L, Marsh HM, Famell MB, Washington J 2nd, Thompson RL. Limited usefulness of quantitative culture of blood drawn through the device for diagnosis of intravascular.. device..related bacteremia. JClin MicrobioI1989;27:1431-3.
46. Sherertz R, Heard S, Raad I, Gentry L. Culturing catheter tips is an insensitive method for diagnosis triple lumen vascular catheter infection [Abstract 818]. In: Programs and abstracts of the 32nd interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1992. 47. Raad I, Davis, Khan A, Tarrand J, Elting L, Bodey GP. Impact of central venous catheter removal on the recurrence of catheter.. related coagulase negative staphylococcal bacteremia. Infect Control Hosp Epidemiol:1992;13:215-21.
45. Hoen B, Weber M, Gerard A, et al. Diagnosis of catheter.. related septicemia: a comparison of quantitative tip culture and differential blood culture {Abstract 456]. In: Programs and abstracts of the 31st interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Soci.. ety for Microbiology, 1991.
48. Mosca R, Curtas S, Forbes B, et al. The benefits of isolator cuI.. tures in the management of suspected catheter sepsis. Surgery 1987;102:718-23. 49. Cobb DK, High KP, Sawyer RG, et al. A controlled trial of scheduled repla\:ement of central venous and pulmonary.. artery catheters. N Eng J Med 1992;327:1062..8.
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Approximately 5 million central venous catheters (CVes) of various types are sold in the United States each year. 1 Many of these catheters are inserted in hos.. pitalized patients on a short.. term basis for hemody.. namic monitoring or administration of drugs, parenteral nutrition, fluid therapy, and blood products. Long.. term, tunneled CVCs and implantable ports are inserted for ease of venous access in patients with malignancy or other serious diseases requiring prolonged courses of in.. fusion therapy. These catheters are often maintained by the patient on an outpatient basis, with the help of a visiting nurse from a home health agency. Complications of CVCs include occlusion, throm.. bophlebitis, and infection, each of which may lead to ex.. tra hospital costs. The incidence of primary nosocomial bloodstream infections has increased twofold to threefold in the past decade. 2 The relative frequencies of staphylo.. cocci, Candida species, and Enterococcus species among the etiologic agents of these infections have increased sig.. nificantly. CVCs now account for 90% of all catheter.. re.. lated bloodstream infections. 3
Numerous published studies have focused on risk factors for catheter complications and methods of pre.. venting them. Many of these publications have con.. cluded with recommendations for clinical practice, but little information is available regarding the frequency with which such practices are implemented. We conducted a survey of clinicians responsible for CVC maintenance in both hospital and outpatient set.. tings to assess frequencies of practices being employed today in the maintenance of CVCs for the prevention of complications and in the documentation of blood.. stream infection; the most important infectious compli.. cation of CVCs.
Methods A questionnaire was distributed to a convenience sample of persons attending the annual conference of the Na.. tional Association of Vascular Access Networks, held in New Orleans on September 24 through 26, 1992. The
Mark A. Clemence, MD, is a board certified Infectious Disease Physician in private practice at St. Luke's Hospital and Medical Center in Milwaukee, Wisconsin. Dr. Clemence is also a Clinical Instructor with a residency program at The Medical College of Wisconsin.
Diane Walker, RN is a registered nurse at the University of Virginia Health Sciences Center and specializes in oncology nursing. Barry M. Farr, MD, MSc, is the Hospital Epidemiologist at the University of Virginia Hospital. He is also Associate Professor of Internal Medicine at the University of Virginia School of Medicine where he is also Director of the Epidemiology Program. Reproduced from Clemence MA, Walker 0, Farr, BM. Central venous catheter practices: Results of a survey. American Journal of Infectious Control 1994; 23:5-12. With permission from Mosby-Year Book, Inc.
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Frequencies of catheter dressing types
TABLE 1
Type of dressing Transparent Gauze totally covered by tape Gauze not totally covered by tape
TABLE 2
Teaching Hospital
Nonteaching Hospital
Home Health Agency
No. 19/23 5/23 4/23
No. 17/21 7/21 1/21
No. 45/48 4/48 4/48
%
83 22 17
81 33 5
%
94 8 8
Frequencies of catheter dressing changes
Twice daily Once daily Three times per week Twice weekly Once weekly
Teaching Hospital
N onteaching Hospital
Home Health Agency
No. 0/19 1/19 11/19 4/19 3/19
No. 0/19 1/19 7/19 6/19 5/19
No. 1/46 3/46 20/46 4/46 18/46
%
0 5 58 21 16
survey consisted of 15 questions related to specific prac, tices in the maintenance of CVCs. Questions in the sur, vey focused on infection control measures, methods for maintaining catheter patency, and the collection of blood samples from the catheter for diagnostic tests, in' cluding blood cultures.
Results Ninety,three (44%) of the 212 persons attending the conference completed the questionnaire. Most respon, dents were nurses affiliated with hospitals or home health agencies. Twenty,one of the respondents (23%) represented teaching hospitals, 23 (25%) represented nonteaching hospitals, and 48 (52%) represented home health agencies. Twenty,four states were represented by respondents to the survey, with 12 respondents (13%) from the northeast, 24 (26%) from the southeast, 16 (1 7%) from the Midwest, and 41 (44%) from the west, including three from Alaska and one from Hawaii.
Infection Control Measures Dressings. Transparent dressings were used by most respondents from all types of institution, as indi, cated in Table 1. Cotton gauze dressings were used by only a minority of the respondents. Clean technique was
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%
0 5 37 32 26
%
2 7 43 9 39
used for dressing changes by 17% (4/23) of respondents from teaching hospitals, 19% (4/21) from nonteaching hospitals, and 77% (37/48) from home health agencies. Dressing Changes. Most respondents indicated that CVC dressings were changed three times per week on average. There was considerable variation, as indicated in Table 2. Sterile technique was used for dressing changes by 87% of respondents from teaching hospitals (20/23), 90% (19/21) from nonteaching hospitals, and 77% (37/ 48) from home health agencies. Masks were used in the hospital for dressing changes by 52% of teaching hospital respondents (12/23) and 67% of those from nonteaching hospitals (14/21). Masks were recommended for dressing changes at home by 22% (5/23) of the respondents from teaching hospitals, 38% (8/21) from nonteaching hospitals, and 40% (19/48) from home health agencies. Antiseptics and Antimicrobial Ointments. Alcohol and povidone,iodine solutions were the antiseptics most frequently used for skin preparation at the time of dress' ing changes, as indicated in Table 3. Antimicrobial oint, ment was used for dressing changes by 43% of those from teaching hospitals (10/23),76% (16/21) fromnonteach, ing hospitals, and 33% of those from home health agen,
31
TABLE 3 Frequencies of antiseptic use for dressing changes Teaching Hospital
Alcohol Povidone.. iodine Hydrogen peroxide Chlorhexidine
N onteaching Hospital
Home Health Agency
No.
%
No.
%
No.
%
18/23 22/23 6/23 3/23
78 96 26 13
15/21 21/21 6/21 1/21
71 100 29 5
46/48 45/48 5/48 2/48
96 100 10 4
TABLE 4 Frequency of flushes for tunneled catheters Teaching Hospital
As needed Three times daily Twice daily Daily Three times weekly Twice weekly Once weekly Once monthly
Nonteaching Hospital
No.
%
No.
0/19 2/19 2/19 10/19 2/19 2/19 1/19 0/19
0 11 11 53 11 11 5 0
1/19 2/19 0/19 10/19 1/19 0/19 3/19 0/19
Home Health Agency
%
5 11 0 53 5 0 16 0
No.
%
0/42 0/42 2/42 29/42 3/42 0/42 7/42 1/42
0 0 5 69 7 0 17 2
TABLE 5 Frequency of flushes for implantable ports Teaching Hospital
As needed Three times a day Twice daily Once daily Once weekly Once monthly
No.
%
No.
0/19 2/19 1/19 1/19 0/19 15/19
0 11 5 5 0 79
1/19 0/19 1/19 2/19 0/19 13/19
cies (16/48). Among those who used antimicrobial oint.. ment, povidone..iodine was used by 100% of those from teaching hospitals (10/10), 81 % of those from nonteach.. ing hospitals (13/16), and 81 % of those from home health agencies (13/16). Polymyxin..neomycin..bacitracin ointment was used by 10% (1/10) from teaching hospitals, 81 % (13/16) from nonteaching hospitals, and 50% of those representing home health agencies (8/16). No re.. spondents indicated that mupirocin ointment was used for dressing changes.
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Nonteaching Hospital
Home Health Agency
No.
%
5
0/43 0/43 0/43 1/43 5/43 37/43
o 5 11
o 68
%
o o o 2
12 86
Measures to Maintain Catheter Patency Heparin flushes were used to maintain the patency of noninfusing CVCs (excluding Groshong catheters) by 96% (22/23) from teaching hospitals, 95% (20/21 from nonteaching hospitals, and 98% of those representing home health agencies (47/48). Saline solution flushes without heparin were used by 9% (2/23) from teaching hospitals, 10% (2/21) from nonteaching hospitals, and 25% (12/48) from home health agencies.
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TABLE 6
Frequency distribution of the amount of blood withdrawn from catheter before diagnostic specimen collection Teaching Hospital
N onteaching Hospital
Home Health Agency
Amount (ml)
No.
%
No.
%
No.
%
<5 5-9
6/23 16/23 1/23
26 70 4
8/20 9/20 3/20
40 45 15
8/46 34/46 4/46
17 74 9
~10
The most commonly used concentration of heparin to maintain noninfusing CVCs was 100 units/ml (77% of respondents from teaching hospitals [17/22],70% from nonteaching hospitals [14/20], and 87% [41/47] from home health agencies). A concentration of 10 units/ml was used by 320/0 of those from teaching institu, tions (7/22), 40% (8/20) from nonteaching hospitals, and 19% (9/47) from home health agencies. Frequencies of flushes used for tunneled catheters and for implantable ports are indicated in Tables 4 and 5, respectively.
Aspiration of Blood for Diagnostic Tests Personnel responsible for routinely drawing blood samples from CVCs in teaching hospitals included nurses (96% [22/23]) physicians (26% [6/23/cb), laboratory personnel (4% [1/23]), and medical students (9% [2/23]). In non, teaching hospitals, nurses (100% [21/21]) and physicians (10% [2/21]) drew the blood. Respondents from home health agencies indicated that blood samples were drawn from CVCs by nurses (79% [38/48]) and physicians (6% [3/48]). Blood cultures were drawn from CVCs by 87% of respondents from teaching hospitals (20/23), 71 % of respondents from nonteaching hospitals (15/21), and 83 % of those from home health agencies (40/48). Of those who used CVCs to draw blood cultures, periph, eral cultures were drawn as well by 95% of those repre, senting teaching hospitals (19/20), 100% of those from nonteaching hospitals (15/15), and 98% of those from home health agencies (39/40). Quantitative blood cultures were performed by those accessing CVCs for blood cultures by 50% of re, spondents representing teaching hospitals (10/20), 33% of those from nonteaching hospitals (5/15), and 23% of those from home health agencies (9/40). Masks were used when drawing blood samples by 22% (5/23) from teaching hospitals, 19% (4/21) from
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nonteaching hospitals, and 8% (4/48) from home health agencies. Catheter ports were disinfected with alcohol before accessing CVCs by 83% of respondents from teaching hospitals (19/23), 71 % of those from nonteaching hospi, tals (15/21), and 90% of those from home health agencies (43/48). Povidone, iodine disinfection was used before accessing CVCs by 48% of respondents from teaching hospitals (11/23), 62% of respondents from nonteaching hospitals (13/21), and 52% of those from home health agencies (25/48). Both alcohol and povidone,iodine were used for disinfecting ports before accessing CVCs by 35% of respondents from teaching hospitals (8/23),33% of those from nonteaching hospitals (7/21), and 42% of those from home health agencies (20/48). Blood samples were not drawn from CVCs for cer, tain laboratory tests. Fifty,seven percent of respondents from teaching hospitals (13/23) did not draw blood from CVCs for the following reasons: antibiotic levels only (one), cyclosporine levels (two), coagulation levels only (nine), and an unspecified reason (one). Forty,three per' cent of respondents from nonteaching hospitals (9/21) did not draw blood from CVCs for the following reasons: antibiotic levels only (one), antibiotic levels and serum bactericidal levels (one), antibiotic levels and coagula, tion profiles (two), coagulation profiles only (three), and an unspecified reason (two). Sixty,five percent of re, spondents from home health agencies (31/48) did not draw blood from CVCs for the following reasons: antibi, otic levels only (10), antibiotic levels and coagulation profiles (five), coagulation profiles only (14), and an un, specified reason (two). The amount of blood withdrawn from CVCs before collection of specimens for laboratory tests is indicated in Table 6. In all but one case (one respondent from a teaching institution), the blood was discarded rather than returned to the patient after the specimen was collected.
33
Discussion This study describes practices being employed for the prevention of complications related to CVCs by hospi, tals and home health agencies, as represented by respon, dents to our survey, throughout the United States today.
Infection Control Practices Multiple studies have examined the risk factors for in' fection associated with CVCs. Most have focused on short'term CVCs in hospitalized patients, however, and relatively little information is available regarding modi, fiable risk factors for infection with long,term tunneled CVCs.
Dressing Changes Transparent dressings were the most frequent type of CVC dressing used within each group. Several recent studies have demonstrated an increase in infectious corn, plications associated with the use of transparent dress' ings. 4'7 A recent metaanalysis of previously published studies demonstrated a statistically significantly in' creased risk of catheter tip colonization for catheters covered with transparent dressings, as compared with dressings consisting of cotton gauze covered by tape, and a concomitant trend toward an increased risk of cath, eter,related bacteremia. 8 In one study,9 bacterial skin colonization was significantly greater under conven, tional transparent dressings left on for a week than under gauze dressings changed every other day. Greater rates of skin colonization associated with some types of transpar, ent dressings may be caused by differences in moisture vapor permeability, oxygen transmission, or cutaneous adherence. I Disadvantages of transparent dressings in' clude poor adhesion when used with topical ointments, patient distress at the sight of the catheter insertion site, and greater expense.I,IO One studyll reported a signifi, cantly greater risk of unspecified catheter malfunction with transparent dressings than with dry, sterile gauze. The most recent randomized trial comparing gauze with transparent dressings l2 found no difference in infection or colonization rates. Consistent findings from additional studies are needed, however, to reverse the impression that transparent dressings are associated with an in, creased risk with short,term catheters. Two studies of
34
transparent dressings on tunneled CVCs 9,13 found no in, crease in the risk of infection. After weeks of healing and tissue infiltration around the catheter cuff, the risk of in' fection decreases considerably, and transparent dressings may not significantly alter the acceptably low rates of in, fection observed with tunneled catheters. Some institu, tions do not even recommend dressings for such healed catheter sites and use only an adhesive strip bandage or a piece of paper tape to help secure the catheter to the chest. 14 Dressings were changed three times per week by most respondents. In 1982, the Centers for Disease Con, trol 15 published its guidelines for the care of intravascular catheters. These recommendations, which were not based on the results of randomized trials, stipulated that dressings should be inspected by palpation at least every 24 hours. A large, randomized trial 16 showed no differ, ence in infection rates when dressings for peripheral in' travenous catheters were changed every 2 days rather than being changed as clinically indicated. Maki l has recommended that dressings used on CVCs in patients in the intensive care unit be changed every other day. More than half of the respondents representing both teaching and nonteaching hospitals indicated that masks were used for dressing changes while the patient was in the hospital. Conversely, most did not use masks for dressing changes at home. No data are available to document the benefit of this practice.
Antiseptics Nearly all respondents in each category indicated that povidone,iodine was used as a skin antiseptic for dress' ing changes, and most respondents in each category in' dicated that 70% alcohol was also used. A recent clinical trial assessing peripheral blood culture contami, nation rates l7 demonstrated significantly less contami, nation with tincture of iodine than with iodophor (6.25% contamination for iodophor vs. 3.74% for tinc, ture of iodine, p < 0.00001), suggesting superior anti, septic properties for tincture of iodine compared with povidone,iodine. Although tincture of iodine (1 % to 2%) may be slightly more effective than 70% alcohol or iodophors, the latter two preparations have been associ, ated with a lower incidence of local adverse reactions. 18 Hexachlorophene and benzalkonium compounds should not be used as skin preparations for catheter dressings
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because of an increased risk of infectious complications with Pseudomonas and Enterobacter species. 19 Maki and coworkers 20 recently demonstrated superior efficacy of a 2% solution of chlorhexidine glu.. conate for skin antisepsis with dressing changes for short.. term CVCs compared with 70% alcohol or 10% povidone.. iodine (2.3 local catheter.. related infections/ 100 catheter days vs 7.1 and 9.3 for alcohol and povidone.. iodine, respectively; p = 0.02). Although some of the respondents indicated that chlorhexidine was used as an antiseptic, no commercial formulation was available for use as an antiseptic for catheter dress.. ing changes at the time of the survey. Three fourths of respondents from nonteaching hospitals indicated that antimicrobial ointment was used for dressing changes, whereas fewer than half of the respondents from teaching hospitals and home health agencies indicated that they used such ointment. Povidone.. iodine ointment was shown to significantly reduce the risk of subclavian dialysis catheter.. related bloodstream infections in a recent randomized, con.. trolled trial,21 but six (14%) of the 42 hospitals and agencies in this survey that used ointment did not use povidone . . iodine ointment. Polymyxin.. neosporin.. bacitracin ointment, which was used by 11 (26%) of the 42 respondents who used ointment, has been dem.. onstrated to halve the risk of bacterial colonization of catheters but also to increase the risk of Candida coloni.. zation five times. 22 Several studies 23,25 have reported an increase in catheter.. related bloodstream infections by Candida species, which may be associated with consid.. erable morbidity and mortality. For this reason, Flowers and associates 22 recommended against the use of poly.. myxin.. neomycin.. bacitracin ointment on CVCs. This concern may be more important early after placement of long.. term tunneled catheters than later, after the catheter site has healed, because catheter infection may be more likely to occur by the intraluminal route after prolonged catheterization.
Flushing The overwhelming majority of respondents in all three categories indicated that heparin was used to maintain patency of noninfusing CVCs. Early studies 26,28 demon.. strated that the addition of heparin to intravenous solu.. tions diminished the incidence of infusion phlebitis.
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These studies involved continuous infusions; the ben.. efit of heparin in preventing phlebitis in noninfusing CVCs is less certain. Various flushing protocols for maintenance of CVCs have been developed and adopted by individual institu.. tions; however, no consensus has been established. 29 In 1985, Gillies and associates 3o found that flushing Hickman catheters with normal saline solution only did not increase the complication rate. Several studies,31,34 including two metaanalyses, similarly demonstrated that saline solution may be as effective as heparin in main.. taining patency and preventing thrombophlebitis. The small doses of heparin used to flush vascular catheters are not without risk; adverse reactions, such as bleeding complications, have been reported. 34 In addition, there is a potential for interaction of heparin with other drugs if the catheter is not properly flushed with saline solution before use. Estimated annual savings to individual hospi.. tals from discontinuing heparin flushes have ranged from $10,000 to $60,000. 35 '38 There was considerable variation among respon.. dents regarding the frequency of flushing, with most re.. spondents indicating daily flushes for tunneled catheters and monthly flushes for implantable ports. Hickman and Broviac catheters are generally flushed every 12 to 24 hours while the patient is in the hospital and daily or ev.. ery other day while the patient is at home. 14 Two recent prospective studies 29,32 demonstrated no significant dif.. ference in CVC complications after switching from daily or twice daily flushing to a weekly flushing regimen with saline solution. Implantable ports are usually flushed with heparin every 4 weeks, but no controlled studies are available regarding this practice.
Blood Collection from Indwelling Catheters for Blood Cultures Blood cultures were drawn through indwelling catheters by most respondents in each category. In recent stud.. ies,39,40 such qualitative blood cultures aspirated from indwelling catheters were associated with a higher rate of false . . positive cultures than that for specimens drawn from peripheral veins. Most respondents also drew qualitative cultures from a peripheral vein, but many clinicians tend to treat positive blood culture results as indicating bacteremia even if results of all peripheral cultures are negative.
35
Quantitative blood cultures were used by one half of the respondents representing teaching institutions, one third of those at nonteaching hospitals, and fewer than one fourth of those from the home health agencies. The use of quantitative blood cultures was first described in 1979, when Wing and associates 41 suggested that blood drawn through an infected venous catheter should result in higher quantitative colony counts than found with blood drawn from a peripheral vein. Bacteremia caused by experimentally induced bacterial peritonitis in a rabbit model also resulted in higher bacterial concentrations in blood aspirated from a CVC than in blood from a periph.. eral vein, presumably because the liver, spleen, and lung act as filters for bacteria. 42 The ratio of concentrations never exceeded 4: 1 in this animal model, so the investi.. gators suggested that the ratio of bacterial colonies in blood drawn through a CVC compared with blood from a peripheral vein should be greater than 5:1 with catheter.. related bacteremia. 42 Catheter infection itself, however, was not studied in the model. Four studies 43-46 tested this hypothesis in patients with suspected infection by using direct catheter segment cultures, the standard method of the past two decades, as a "gold standard." The test per.. formance of paired quantitative blood cultures varied widely in these studies. The use of quantitative cultures cannot be routinely recommended until more consis.. tently accurate results are achieved in such studies. Removal of a short.. term CVC from a patient with suspected catheter infection may be helpful in several ways: (1 )by allowing culture of catheter segments for diagnosis, (2) by removing a foreign body from the site of infection and thus promoting a faster cure than with antibiotic therapy alone, and (3) by preventing recur.. rence of bacteremia after completion of antibiotic therapy.47 The principal disadvantage of removing the catheter for culture is the unnecessary cost of the re.. placement catheter, of radiographs required to confirm tip position, and of clinicians' time to do these proce.. dures for the many cases in which the catheter is not the source of infection. 48 ,49 With tunneled catheters, cli.. nicians are unlikely to remove the catheter immediately even if results of paired quantitative blood cultures are positive. They usually prefer to treat the bacteremia with antibiotics and leave the catheter in place if the patient's condition responds, as occurs with most bacteremias in such patients. Further studies of the ac.. curacy and cost.. effectiveness of paired quantitative blood cultures are needed.
36
Conclusion The results of this survey reflect practices in use today for the maintenance of CVCs, although respondents to a survey at a national conference on venous.. access devices may not be representative of caregivers at all health care facilities. Considerable variation existed within but not between the various types of health care organizations represented in the survey. The increasing acuity of illness among hospitalized patients and the increasingly fre . . quent use of CVCs may largely explain the increasing incidence of nosocomial bloodstream infection observed during the past decade, but some of the practices docu.. mented in this survey may also have contributed. The high frequency of use of transparent dressings, for ex.. ample, may have contributed to the observed increase in the overall rate of infection. The use of polymyxin.. neomycin.. bacitracin ointment on CVCs may have con.. tributed to the increased rate of Candida infection. The increasing use during the past decade of qualitative blood cultures aspirated from indwelling catheters may have resulted in an increased rate of pseudobacteremia; such cases are counted as bloodstream infections according to Centers for Disease Control and Prevention definitions if the physician chooses to treat the patient with antibi.. otics because of the positive blood culture. We wish to thank Donna C. McGraw for technical assistance in preparing this article.
References 1. Maki D. Infections due to infusion therapy. In: Bennett JV, Brachman PS, eds. Hospital infections. Boston: Little, Brown, 1992:849. 2. Banerjee SN, Emori TG, Culver OH, et al. Secular trends in nosocomial primary bloodstream infections in the United States, 1980-1989. Am J Med 1991:91 (SuppI3B):87S-9S. 3. Maki DG. Nosocomial bloodstream infections [Abstract 3]. In: Proceedings of the third decennial international conference on nosocomial infections. Atlanta: Centers for Disease Control and the National Foundation for Infectious Diseases, 1990. 4. Conly J, Grieves K, Peters B. A prospective, randomized study comparing transparent and dry gauze dressings for central venous catheters. J Infect Dis 1989;159:310-9. 5. Katich M, Band J. Local infection of the intravenous,cannulae wound associated with transparent dressings. J Infect Dis 1985; 151 :971-2. 6. Powell C, Regan C, Fabri P, Ruberg R. Evaluation of Opsite catheter dressings for parenteral nutrition: a prospective ran, domized study. JPEN J Parenter Enter Nutr 1982;6:43-6.
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7. Craven D, Lichtenberg D, Kunches M, et al. A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites. Infect Control 1985;6:361-6. 8. Hoffman K, Weber D, Samsa G, Rutala W. Transparent poly.. urethane film as an intravenous catheter dressing: a meta.. analysis of the infection risks. JAMA 1992;267:2072-6. 9. Maki DG, Will L. Colonization and infection associated with transparent dressings for central venous, arterial, and Hickman catheters: a comparative trial [Abstract 991]. In: .Program and . abstracts of the 24th interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1984. 10. Hampton A, Sherertz R. Vascular..access infections in hospi.. talized patients. Surg Clin N Am 1989;68:57-7l. 1l. Gantz N, Presswood G, Goldberg R, Doem G. Effects of dress.. ing type and change interval on intravenous therapy compli.. cation rates. Diagn Microbiol Infect. Dis 1984;2:325-32. 12. Maki DO, Stolz SM, Wheeler SJ, Mermel LA. A prospective, randomized, three..way clinical comparison of a novel highly permeable polyurethane dressing with 442 Swan..Ganz cath.. eters [Abstract 825]. In: Programs and abstracts of the 32nd interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiol.. ogy, 1992. 13. Shivnan JC, McGuire D, Freedman S, et al. Comparison of transparent adherent and dry sterile gauze dressings for long.. term central catheters in patients undergoing bone marrow transplant. Oncol Nurs Forum 1991;18:1349-56. 14. Lucas A. A critical review of venous access devices: the nurs.. ing perspective. Curr Issues Cancer Nurs Pract 1993;1:1-10. 15. Simmons B, Hooton T, Wong E, AlIen J. Guidelines for preven.. tion of intravascular infections. Intravasc Infect 1981;3:62-79. 16. Maki DG, Ringer M. Evaluation of dressing regimens for pre.. vention of infection with peripheral intravenous catheters. JAMA 1987;258:2396-403. 17. Strand C, Wajsbort R, Sturman K. Effect of iodophor vs iodine tincture skin preparation on blood culture contamination rate. JAMA 1993;269:1004-6. 18. Decker M, Edwards K. Central venous catheter infections. Pe.. diatric Clin N Am 1988;35:579-612. 19. Maki D, Goldmann D, Rhame F. Infection control in intrave.. nous therapy. Ann Intern Med 1973;79:867-87. 20. Maki D, Ringer M, Alvarado C. Prospective randomized trial of povidone..iodine, alcohol, and chlorhexidine for prevention of infection associated with central venous and arterial cath.. eters. Lancet 1991;338:339-43. 2l. Levin A, Mason A, Jindal K, et al. The value of topical povidone.. iodine (PV.. I) ointment in the prevention of hemodialysis related sepsis [Abstract 1078]. In: Programs and abstracts of the 29th interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiology, 1989. 22. Flowers R, Schwenzer R, Kople R, Fisch M, Tucker S, Farr B. Ef.. ficacy of an attachable subcutaneous cuff for the prevention of intravascular catheter..related infections. JAMA 1989;261:87883. 23. Zinner S, Denney..Brown B, Braun P, Burke J, Toala P, Kass E.
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24.
25.
26.
27.
28. 29.
30.
3l.
32.
33.
34.
35.
36. 37. 38. 39.
40.
4l.
42.
Risk of infection with intravenous indwelling catheters: effect of application of antibiotic ointment. J Infect Dis 1969; 120: 616..9. Maki D, Band J. A comparative study of polyantibiotic and iodophor ointments in prevention of vascular catheter..related infection. Am J Med 1981;70:739-44. Norden C. Application of antibiotic ointment to the site of venous catheterization: a controlled trial. J Infect Dis 1969; 120:611-5. Tanner W, Delaney P, Hennessey T. The influence of heparin on intravenous infusions: a prospective study. Br J Surg 1980; 67:311-2. Bailey MJ. Reduction of catheter..associated sepsis in parent.. eral nutrition using low..dose intravenous heparin. BMJ 1979; 1:1671-3. Daniell H. Heparin in the prevention of infusion phlebitis: a double..blind controlled study. JAMA 1973;226:1317-2l. Kelly K, Dumenko L, McGregor S, McHutchion M. A change in flushing protocols of central venous catheters. Oncol Nurs Forum 1992;19:599-605. Gillies H, Rogers HJ, Johnston J, Harper PG, Rudge CJ. Is re.. peated flushing of Hickman catheters necessary? BMJ 1985; 290:1708. Weightman N, Simpson E, Speller D, Mott M, Oakhill A. Bacteremia related to indwelling central venous catheters: prevention, diagnosis, and treatment. Eur J Clin Microbiol In.. fect Dis 1988;7:125-9. Smith S, Dawson S, Hennessey R, Andrew M. Maintenance of the patency of indwelling central venous catheters: is hep.. arin necessary? Am J Pediatr Hematol Oncol1991;13:141-3. Peterson F, Kirchoff K. Analysis of the research about heparin.. ized versus nonheparinized intravascular lines. Heart Lung 1991;20:631-42. Goode C, Titler M, Rakel B, Ones D. A meta..analysis of ef.. fects of heparin flush and saline flush: quality and cost impli.. cations. Nurs Res 1991;40:324-30. Taylor N, Hutchison E, Milliken W, Larson E. Comparison of normal versus heparinized saline for flushing infusion devices. J Nurs Qual Assur 1989;3:49-55. Swerling R. Normal saline or dilute heparin for heparin lock flush? Infusion 1982;6:123-4. Dunn D, Lenihan S. The case for the saline flush. Am J Nurs 1987;87:798-9. Cyganski J, Donahue J, Heaton J. The case for the heparin flush. Am J Nurs 1987;87:796-7. Bryant JK, Strand CL. Reliability of blood cultures collected from intravascular catheter versus venipuncture. Am J Clin Pathol1987;88:113-6. Bates DW, Goldman K, Lee TH. Contaminant blood cultures and resource utilization: the true consequences of false..positive results. JAMA 1991;265:365-9. Wing E, Norden C, Shadduck R, Winkelstein A. Use of quan.. titative bacteriologic techniques to diagnose catheter..related sepsis. Arch Intern Med 1979;139:482-3. Flynn P, Shenep J, Stokes D, et al. In situ management of con.. firmed central venous catheter..related bacteremia. Pediatr In.. fect Dis J 1987;6:729-34.
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43. Douard MC, Marie 0, Clementi E, et al. Does a negative cath.. eter tip culture exclude the diagnosis of catheter..related bact.. eremia? [Abstract 455] In: Programs and abstracts of the 31 st interscience conference on antimicrobial agents and chemo.. therapy. Washington, DC: American Society for Microbiology, 1991. 44. Paya CV, Guerra L, Marsh HM, Famell MB, Washington J 2nd, Thompson RL. Limited usefulness of quantitative culture of blood drawn through the device for diagnosis of intravascular.. device..related bacteremia. JClin MicrobioI1989;27:1431-3.
46. Sherertz R, Heard S, Raad I, Gentry L. Culturing catheter tips is an insensitive method for diagnosis triple lumen vascular catheter infection [Abstract 818]. In: Programs and abstracts of the 32nd interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Society for Microbiology, 1992. 47. Raad I, Davis, Khan A, Tarrand J, Elting L, Bodey GP. Impact of central venous catheter removal on the recurrence of catheter.. related coagulase negative staphylococcal bacteremia. Infect Control Hosp Epidemiol:1992;13:215-21.
45. Hoen B, Weber M, Gerard A, et al. Diagnosis of catheter.. related septicemia: a comparison of quantitative tip culture and differential blood culture {Abstract 456]. In: Programs and abstracts of the 31st interscience conference on antimicrobial agents and chemotherapy. Washington, DC: American Soci.. ety for Microbiology, 1991.
48. Mosca R, Curtas S, Forbes B, et al. The benefits of isolator cuI.. tures in the management of suspected catheter sepsis. Surgery 1987;102:718-23. 49. Cobb DK, High KP, Sawyer RG, et al. A controlled trial of scheduled repla\:ement of central venous and pulmonary.. artery catheters. N Eng J Med 1992;327:1062..8.
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