Prevention of intravascular catheter-related infections

PURPOSE: To review the literature on prevention of intravascular catheter-related infections. DATA SOURCES: The MEDLINE database, conference proceedings, and bibliographies of review articles and book chapters were searched for relevant articles. Primary authors were contacted directly if data were incomplete. STUDY SELECTION: Studies met the following criteria unless otherwise stated: Trials were prospective and randomized; catheters were inserted into new sites, not into old sites over guidewires; catheter cultures were done by using semi-quantitative or quantitative methods; and, for prospective studies, catheter-related bloodstream infection was confirmed by microbial growth from percutaneously drawn blood cultures that matched catheter cultures. DATA EXTRACTION: Data on population, methods, preventive strategy, and outcome (measured as catheter-related bloodstream infections) were gathered. The quality of the data was graded by using preestablished criteria. DATA SYNTHESIS: The recommended preventive strategies with the strongest supportive evidence are full barrier precautions during central venous catheter insertion; subcutaneous tunneling short-term catheters inserted in the internal jugular or femoral veins when catheters are not used for drawing blood; contamination shields for pulmonary artery catheters; povidone-iodine ointment applied to insertion sites of hemodialysis catheters; specialized nursing teams caring for patients with short-term peripheral venous catheters, especially at institutions with a high incidence of catheter-related infection; no routine replacement of central venous catheters; antiseptic chamberfilled hub or hub-protective antiseptic sponge for central venous catheters; and use of chlorhexidine-silver sulfadiazine-impregnated or minocycline-rifampin-impregnated short-term central venous catheters if the rate of infection is high despite adherence to other strategies that do not incorporate antimicrobial agents (for example, maximal barrier precautions). CONCLUSIONS: Simple interventions can reduce the risk for serious catheter-related infection. Adequately powered randomized trials are needed.     

Triple- vs single-lumen central venous catheters. A prospective study in a critically ill population

To evaluate a new multilumen central venous catheter we prospectively compared the infection rates of 63 single-lumen and 157 triple-lumen catheters in 145 critically ill patients. Using acute physiology scores, severity of illness was shown to be similar in the two patient groups. There were no significant differences in the rate of catheter colonization or catheter-related sepsis comparing single-lumen with triple-lumen catheters. However, the use of total parenteral nutrition or insertion at the femoral vein site significantly increased the rate of colonization. The only factor that was clearly associated with catheter sepsis was the duration of catheterization. Catheter sepsis increased from 1.5% to 10% when the period of catheterization exceeded 6 days. We conclude that the use of triple- and single-lumen central venous catheters in critically ill patients entails similar risks of infection.     

Prospective evaluation of risk factors for bloodstream infection in patients receiving home infusion therapy.

BACKGROUND: Intravenous therapy in the outpatient and home settings is commonplace for many diseases and nutritional disorders. Few data are available on the rate of and risk factors for bloodstream infection among patients receiving such therapy. OBJECTIVE: To determine rates of and risk factors for bloodstream infection among patients receiving home infusion therapy. DESIGN: Prospective, observational cohort study. SETTING: Cleveland, Ohio, and Toronto, Ontario, Canada. PATIENTS: Patients receiving home infusion therapy through a central or midline catheter. MEASUREMENTS: Primary laboratory-confirmed bloodstream infection. RESULTS: Among 827 patients (988 catheters), the most common diagnoses were infections other than HIV (67%), cancer (24%), nutritional and digestive disease (17%), heart disease (14%), receipt of bone marrow or solid organ transplants (11%), and HIV infection (7%). Sixty-nine bloodstream infections occurred during 69,532 catheter-days (0.99 infections per 1000 days). In a Cox regression model with time-dependent covariates, independent risk factors for bloodstream infection were recent receipt of a bone marrow transplant (hazard ratio, 5.8 [95% CI, 3.0 to 11.3]), receipt of total parenteral nutrition (hazard ratio, 4.1 [CI, 2.3 to 7.2]), receipt of therapy outside the home (for example, in an outpatient clinic or physician's office) (hazard ratio, 3.6 [CI, 2.2 to 5.9]), use of a multilumen catheter (hazard ratio, 2.8 [CI, 1.7 to 4.7]), and previous bloodstream infection (hazard ratio, 2.5 [CI, 1.5 to 4.2]). Rates of bloodstream infection per 1000 catheter-days varied from 0.16 for patients with none of these 5 risk factors to 6.77 for patients with 3 or more risk factors. Centrally inserted venous catheters were associated with a higher risk than implanted ports were, but the difference was not statistically significant. CONCLUSION: Bloodstream infections seem to be infrequent among outpatients receiving infusions through central and midline catheters. However, the rate of infection increases with bone marrow transplantation, parenteral nutrition, infusion therapy in a hospital clinic or physician's office, and use of multilumen catheters. Compared with implanted ports or peripherally inserted catheters, centrally inserted venous catheters may confer greater risk for bloodstream infection.     

Prevention of catheter-related bloodstream infection in critically ill patients using a disinfectable, needle-free connector: a randomized controlled trial

OBJECTIVE: The aim of this study was to assess the efficacy of a disinfectable, needle-free connector in the prophylaxis of catheter-related bloodstream infection. METHODS: A randomized controlled trial was performed in a polyvalent intensive care unit. Patients who needed multilumen central venous catheters were randomly assigned to a study or a control group. All catheters were inserted and manipulated according to the Centers for Disease Control and Prevention (CDC) recommendations. Study group patients were equipped with catheters with disinfectable, needle-free connectors whereas control group patients were equipped with catheters with 3-way stopcocks. Two peripheral blood cultures and a semiquantitative culture of the catheter tip were performed on removal of the catheter. RESULTS: The study included 243 patients, with a total of 278 central venous catheters. The catheters' mean insertion duration was 9.9 days. Both groups were comparable regarding patient and catheter characteristics. Incidence rate of catheter-related bloodstream infection was 0.7 per 1000 days of catheter use in the study group, compared with 5.0 per 1000 days of catheter use in the control group (P=.03). CONCLUSIONS: To add a disinfectable, needle-free connector to the CDC recommendations reduces the incidence of catheter-related bloodstream infection in critically ill patients with central venous catheters.     

Chlorhexidine-based antiseptic solution vs alcohol-based povidone-iodine for central venous catheter care

BACKGROUND: Although chlorhexidine-based solutions and alcohol-based povidone-iodine have been shown to be more efficient than aqueous povidone-iodine for skin disinfection at catheter insertion sites, their abilities to reduce catheter-related infection have never been compared. METHODS: Consecutively scheduled central venous catheters inserted into jugular or subclavian veins were randomly assigned to be disinfected with 5% povidone-iodine in 70% ethanol or with a combination of 0.25% chlorhexidine gluconate, 0.025% benzalkonium chloride, and 4% benzylic alcohol. Solutions were used for skin disinfection before catheter insertion (2 consecutive 30-second applications separated by a period sufficiently long to allow for dryness) and then as single applications during subsequent dressing changes (every 72 hours, or earlier if soiled or wet). RESULTS: Of 538 catheters randomized, 481 (89.4%) produced evaluable culture results. Compared with povidone-iodine, the chlorhexidine-based solution was associated with a 50% decrease in the incidence of catheter colonization (11.6% vs 22.2% [P = .002]; incidence density, 9.7 vs 18.3 per 1000 catheter-days) and with a trend toward lower rates of catheter-related bloodstream infection (1.7% vs 4.2% [P = .09]; incidence density, 1.4 vs 3.4 per 1000 catheter-days). Independent risk factors for catheter colonization were catheter insertion into the jugular vein (adjusted relative risk, 2.01; 95% confidence interval, 1.24-3.24) and use of povidone-iodine (adjusted relative risk, 1.87; 95% confidence interval, 1.18-2.96). CONCLUSION: Chlorhexidine-based solutions should be considered as a replacement for povidone-iodine (including alcohol-based) formulations in efforts to prevent catheter-related infection.     

Are antiseptic-coated central venous catheters effective in a real-world setting?

BACKGROUND: Catheter-related bloodstream infections are common, costly, and morbid. Randomized controlled trials indicate that antiseptic-coated central venous catheters reduce infection rates. OBJECTIVE: To assess the clinical and economic effectiveness of antiseptic-coated catheters for critically ill patients in a real-world setting. METHODS: Central venous catheters coated with chlorhexidine/silver-sulfadiazene were introduced in all patients requiring central venous access in adult intensive care units at the University of Michigan Health System, a large, tertiary care teaching hospital. A pretest-posttest cohort design measured the primary outcome of catheter-related bloodstream infection rate, comparing the 2 years prior to the intervention with the 2 years following the intervention. We also evaluated cost-effectiveness and changes in vancomycin use. RESULTS: The intervention was associated with a 4% per month relative reduction in the incidence of catheter-related bloodstream infection, after controlling for the effects of time. Overall, a 35% relative risk reduction (P < .0003) in the catheter-related bloodstream infection rate occurred in the posttest phase. The use of antiseptic-coated catheters reduced costs more than $100,000 annually. Vancomycin use was less in units in which antiseptic catheters were used compared with wards in which these catheters were not used. CONCLUSION: Antiseptic-coated catheters appear to be clinically effective and economically efficient in a real-world setting.     

Microbiology difference between colonized catheters and catheter-related bloodstream infections

BACKGROUND/AIMS: Central vein catheters for patients receiving total parenteral nutrition have a high incidence of colonized catheters and catheter-related bloodstream infections. However, the actual incidence and bacterial pattern have not been well studied. This study was undertaken to investigate the difference in bacteriology between colonized catheters and catheter-related bloodstream infections. METHODOLOGY: From January 1997 to March 1998, 354 patients receiving total parenteral nutrition were included in this study. The patients ranged in age from 49 to 80 years, 151 women and 203 men. Colonized catheters and catheter-related bloodstream infections were defined. RESULTS: The culture was performed in 249 catheter tips (249 of 614, 40.6%). Sixty tips were found to have organisms. The organisms cultured from colonized catheters were Gram(+) aerobic bacteria (34, 56.7%), fungi (14, 23.3%), and Gram(-) aerobic bacteria (12, 20%). The organisms cultured from catheter-related bloodstream infections were fungi (16, 64%), Gram(-) aerobic bacteria (5, 20%), and Gram(+) aerobic bacteria (4, 16%). Dermatogenic infection in colonized catheters should be stressed, but systemic fungal infection in catheter-related bloodstream infections should be emphasized. CONCLUSIONS: A striking difference exists in bacterial species between colonized catheters and catheter-related bloodstream infections. Further studies on different treatment strategy for colonized catheters and catheter-related bloodstream infections should be undertaken. The combined approach of a total parenteral nutrition team, sterile protocols, and early diagnosis of fungemia should be advocated for the total parenteral nutrition patients.     

Intravascular catheter-related infections: advances in diagnosis, prevention, and management

Indwelling vascular catheters are a leading source of bloodstream infections in critically ill patients and cancer patients. Because clinical diagnostic criteria are either insensitive or non-specific, such infections are often overdiagnosed, resulting in unnecessary and wasteful removal of the catheter. Catheter-sparing diagnostic methods, such as differential quantitative blood cultures and time to positivity have emerged as reliable diagnostic techniques. Novel preventive strategies include cutaneous antisepsis, maximum sterile barrier, use of antimicrobial catheters, and antimicrobial catheter lock solution. Management of catheter-related bloodstream infections involves deciding on catheter removal, antimicrobial catheter lock solution, and the type and duration of systemic antimicrobial therapy. Such decisions depend on the identity of the organism causing the bloodstream infection, the clinical and radiographical manifestations suggesting a complicated course, the underlying condition of the host (neutropenia, thrombocytopenia), and the availability of other vascular access sites.     

Catheter-related infections in continuous hemodiafiltration in intensive care patients

BACKGROUND/AIMS: Infection control is of key importance especially in the application of long-term continuous hemodiafiltration (CHDF) involving invasive vascular catheterization to critically ill patients. We investigated hemodialysis catheter-related infections in long-term CHDF. METHODS: We examined catheter infections in 54 patients who were admitted to the intensive care unit and underwent CHDF for 2 weeks or longer. RESULTS: With a total of 155 catheters (1,071 catheter days) studied, catheter colonization and catheter-related bloodstream infection were noted with an incidence rate of 4.8 and 2.7 per 1,000 catheter days, respectively. No difference in catheter colonization rate was observed depending on the catheterization sites or duration of catheterization. Infections were identified in 39 patients (72%) and blood culture positivity was noted in 25 patients (46%). CONCLUSIONS: Since the majority of cases requiring long-term CHDF are complicated with a variety of infections, it is difficult to control infections associated with hemodialysis catheters separately from infections of other types. Systemic infection control should serve as a strategy finally leading to successful control of catheter-related infection.     

Risk of Catheter-Related Bloodstream Infection in Elderly Patients on Hemodialysis

Background and objectives

Elderly patients require tunneled central vein dialysis catheters more often than younger patients. Little is known about the risk of catheter-related bloodstream infection in this population.

Design, setting, participants, & measurements

This study identified 464 patients on hemodialysis with tunneled central vein dialysis catheters between 2005 and 2007 and excluded patients who accrued <21 catheter-days during this period. Outpatient and inpatient catheter-related bloodstream infection data were collected. A Cox proportional hazards regression analysis adjusting for sex, ancestry, comorbidites, dialysis vintage, dialysis unit, immunosuppression, initial catheter site, and first antimicrobial catheter lock solution was performed for risk of catheter-related bloodstream infection between nonelderly (18–74 years) and elderly (≥75 years) patients.

Results

In total, 374 nonelderly and 90 elderly patients with mean (SD) ages of 54.8 (12.3) and 81.3 (4.9) years and dialysis vintages of 1.8 (3.3) and 1.5 (2.9) years (P=0.47), respectively, were identified. Mean at-risk catheter-days were 272 (243) in nonelderly and 318 (240) in elderly patients. Between age groups, there were no significant differences in initial catheter site, type of catheter lock solution, or microbiology results. A total of 208 catheter-related bloodstream infection events occurred (190 events in nonelderly and 18 events in elderly patients), with a catheter-related bloodstream infection incidence per 1000 catheter-days of 1.97 (4.6) in nonelderly and 0.55 (1.6) in elderly patients (P<0.001). Relative to nonelderly patients, the hazard ratio for catheter-related bloodstream infection in the elderly was 0.33 (95% confidence interval, 0.20 to 0.55; P<0.001) after multivariate analysis.

Conclusion

Elderly patients on hemodialysis using tunneled central vein dialysis catheters are at lower risk of catheter-related bloodstream infection than their younger counterparts. For some elderly patients, tunneled central vein dialysis catheters may represent a suitable dialysis access option in the setting of nonmaturing arteriovenous fistulae or poorly functioning synthetic grafts.     

A prospective, randomized study comparing transparent and dry gauze dressings for central venous catheters

Patients having central venous catheters for three or more days were prospectively randomized to receive a transparent (n = 58) or gauze (n = 57) dressing to compare the incidence of insertion site colonization, local catheter-related infection, and catheter-related sepsis. Quantitative cultures of the catheter insertion site (25 cm2) revealed significantly greater colonization (P less than or equal to .009) after 48 h in the transparent versus the gauze dressing group. Local catheter-related infection occurred significantly more often (P = .002) in the transparent (62%) than in the gauze group (24%). Seven episodes of catheter-related bacteremia occurred in the transparent group (16.6%) and none in the gauze group (P = .015). Stepwise logistic regression analysis revealed that cutaneous colonization at the insertion site of greater than or equal to 10(3) cfu/mL (relative risk, 13.16) and difficulty of insertion (relative risk, 5.39) were significant factors for catheter-related infection. These data suggest that transparent dressings are associated with significantly increased rates of insertion site colonization, local catheter-related infection, and systemic catheter-related sepsis in patients with long-term central venous catheters.     

Risk factors for infusion-related phlebitis with small peripheral venous catheters. A randomized controlled trial

OBJECTIVE: To identify risk factors for infusion-related phlebitis with peripheral intravenous catheters. DESIGN: A randomized trial of two catheter materials, with consideration of 21 potential risk factors. SETTING: A university hospital. PATIENTS: Hospitalized adults without granulocytopenia who received a peripheral intravenous catheter. INTERVENTIONS: House officers or ward nurses inserted the catheters, and each insertion was randomized to a catheter made of tetrafluoroethylene-hexafluoropropylene (FEP-Teflon) or a novel polyetherurethane without leachable additives (PEU-Vialon). MEASUREMENTS: Research nurses scored insertion sites each day for inflammation and cultured catheters at removal. RESULTS: The Kaplan-Meier risk for phlebitis exceeded 50% by day 4 after catheterization. intravenous antibiotics (relative risk, 2.00), female sex (relative risk, 1.88), prolonged (greater than 48 hours) catheterization (relative risk, 1.79), and catheter material (PEU-Vialon: FEP-Teflon) (relative risk, 0.73) strongly predicted phlebitis in a Cox proportional hazards model (each, P less than 0.003). The best-fit model for severe phlebitis identified the same predictors plus catheter-related infection (relative risk, 6.19), phlebitis with a previous catheter (relative risk, 1.54), and anatomic site (hand: forearm, relative risk, 0.71; wrist:forearm, relative risk, 0.60). The low incidence of local catheter-related infection was comparable with the two catheter materials (5.4% [95% CI, 3.8% to 7.6%] and 6.9% [CI, 4.9% to 9.6%]); none of the 1054 catheters prospectively studied caused bacteremia. CONCLUSIONS: Multiple factors, including the infusate and the duration of cannulation, contribute to the development of infusion-related phlebitis. The use of peripheral intravenous catheters made of PEU-Vialon appears to pose the same risk for catheter-related infection as the use of catheters made of FEP-Teflon, and PEU-Vialon can permit longer cannulation with less risk for phlebitis. The risk for catheter-related bacteremia with FEP-Teflon and PEU-Vialon catheters is sufficiently low that it no longer seems justifiable to recommend the use of small steel needles for most peripheral intravenous therapy.     

New challenges in the diagnosis, management, and prevention of central venous catheter-related infections

Catheters are the leading source of bloodstream infections in critically ill patients. Because the clinical signs of infection are nonspecific, such infections are overly suspected, which results in unnecessary removal of catheters. A conservative approach might be attempted in mild infections, whereas catheters should always be removed in cases of severe sepsis or septic shock. Nowadays, comprehensive unit-based improvement programs are effective to reduce catheter-related bloodstream infections (CR-BSIs). Rates of CR-BSI higher than 2 per 1000 catheter-days are no longer acceptable. A locally adapted checklist of preventive measures should include cutaneous antisepsis with alcoholic preparation, maximal barrier precaution, strict policy of catheter maintenance, and ablation of useless catheters. Antiseptic dressings and, to a lesser extent, antimicrobial-coated catheters, might be added to the prevention strategies if the level of infections remains high despite implementation of a prevention program. In the case of CR-BSI in intensive care units (ICUs), the catheter should be removed. In the case of persistence of fever or positive blood cultures after 3 days, inadequate antibiotic therapy, endocarditis, or thrombophlebitis should be ruled out.     

Infections caused by aterial catheters used for hemodynamic monitoring

Utilizing a semiquantitative technique for culturing vascular catheters, we prospectively studied the risk and profile of infection caused by arterial catheters used for hemodynamic monitoring in 95 patients with a high risk of nosocomial infection. Of 130 catheters, 23 (18 per cent) produced local infection (larger than or equal to 15 colonies on semi-quantitative culture) and five septicemia (4 per cent). Sixteen of the 23 local infections and all septicemias occurred with catheter placements exceeding four days (p less than 0.001). Other factors associated with an increased risk of infection included insertion by surgical cut-down rather than percutaneously (ninefold increased rate of bacteremia, p = 0.008) and the presence of local inflammation (12-fold increase, p = 0.009). Systemic antimicrobial therapy (given to 80 per cent of the entire group and to four of the five with septicemia) did not protect against catheter-related infection but may account for the predominance of enterococci, Candida and gram-negative bacilli in these infections. Twelve per cent of all nosocomial bacteremias occurring in this critical care unit population originated from an arterial catheter. Indwelling arterial catheters pose a significant risk of bacteremic infection to ctirically ill patients. The percutaneous mode of placement is preferred; when prolonged arterial cannulation is required, the site should be rotated every four days. Local pain or inflammation, or clinical signs of sepsis without an obvious source should prompt removal and culture of the catheter.     

Ultrasound screening for internal jugular vein thrombosis aids the detection of central venous catheter-related infections in patients with haemato-oncological diseases: a prospective observational study

To prove the hypothesis that central venous catheter-related thrombosis and infection are associated, 43 haemato-oncological patients with an internal jugular vein catheter underwent ultrasound screening for thrombosis every 4 d. Catheter-related thrombosis was detected in 13/43 patients (30%). Catheter-related infection, as defined by the U.S. Hospital Infection Control Practices Advisory Committee, was found in 14/43 patients (33%) with colonization of the catheter in two patients, exit site infection in eight patients and catheter-related bloodstream infection in four patients. Catheter-related thrombosis and catheter-related infection coincided in 12 patients and were significantly correlated (Fisher's exact test, P < 0.0001). Detection of thrombosis indicated a catheter-related infection with a superior sensitivity (86% vs 57%) and an equivalent specificity (97%) compared with the presence of clinical signs (erythema, tenderness, warmth or swelling). Neutropenia, which occurred in 32 patients, was found in 13/14 patients (93%) with a catheter-related infection and, therefore, seemed to be an important covariate for the development of a catheter-related infection. This study showed a close correlation between catheter-related thrombosis and infection. Ultrasound screening for thrombosis was helpful for detecting catheter-related infection. These findings could be clinically useful for the handling of central venous catheters in patients with an elevated risk of infectious complications.     

Antibiotic-coated hemodialysis catheters for the prevention of vascular catheter-related infections: a prospective, randomized study

PURPOSE: To determine the efficacy of minocycline-rifampin-coated hemodialysis catheters in reducing catheter-related infections in patients requiring hemodialysis for acute renal failure. METHODS: Between May 2000 and March 2002, 66 patients were randomly assigned to receive a minocycline-rifampin-impregnated central venous catheter and 64 were randomly assigned to receive an unimpregnated catheter. Patients were followed prospectively until the catheter was removed. Catheter-related infection was determined through quantitative catheter cultures, quantitative blood cultures, or both. RESULTS: Both groups of patients were similar in age, sex, underlying disease, type of dialysis (continuous vs. intermittent), neutropenia during catheterization and its duration, catheter insertion difficulties, and administration of blood products or medication. The mean (+/- SD) catheter dwell time was the same in both groups (8 +/- 6 days, P = 0.7). There were seven catheter-related infections (11%), all associated with the use of unimpregnated catheters. Kaplan-Meier estimates for the risk of catheter-related infection showed that coated catheters were less likely to be associated with infection (P = 0.006). CONCLUSION: The use of polyurethane hemodialysis catheters impregnated with minocycline and rifampin decreases the risk of catheter-related infection in patients with acute renal failure.     

Does Heparin Coating Improve Patency or Reduce Infection of Tunneled Dialysis Catheters?

Background and objectives: Tunneled dialysis catheters are prone to frequent malfunction and infection. Catheter thrombosis occurs despite prophylactic anticoagulant locks. Catheter thrombi may also serve as a nidus for catheter infection, thereby increasing the risk of bacteremia. Thus, heparin coating of catheters may reduce thrombosis and infection. This study evaluated whether heparin-coated hemodialysis catheters have fewer infections or greater cumulative survival than noncoated catheters.Design, setting, participants, & measurements: We retrospectively queried a prospective access database to analyze the outcomes of 175 tunneled dialysis catheters placed in the internal jugular vein, including 89 heparin-coated catheters and 86 noncoated catheters. The primary outcome was cumulative catheter survival, and the secondary outcome was infection-free catheter survival.Results: The two patient groups were similar in demographics and clinical and catheter features. Catheter-related bacteremia occurred less frequently with heparin-coated catheters than with noncoated catheters (34 versus 60%, P < 0.001). Cumulative catheter survival was similar in heparin-coated and noncoated catheters (hazard ratio, 0.87; 95% confidence interval, 0.55 to 1.36; P = 0.53). On multiple variable survival analysis including catheter type, age, sex, diabetes, coronary artery disease, peripheral vascular disease, cerebrovascular disease, catheter location, and previous catheter, only catheter location predicted cumulative catheter survival (hazard ratio, 2.03; 95% CI, 1.27 to 3.25, with the right internal jugular location being the reference group, P = 0.003). The frequency of thrombolytic instillation was 1.8 per 1000 catheter-days in both groups.Conclusions: Heparin coating decreases the frequency of catheter-related bacteremia but does not reduce the frequency of catheter malfunction.The two major complications of hemodialysis catheters are thrombosis and infection (1). To prevent catheter thrombosis, an anticoagulant (heparin or citrate) is instilled into both catheter lumens at the end of each dialysis session (2). When a catheter clots despite the anticoagulant lock, a thrombolytic agent [tissue plasminogen activator (tPA) or urokinase] is instilled into the catheter lumens. If the thrombolytic agent is unable to restore catheter patency, the catheter is exchanged over a guidewire.Because catheter thrombosis occurs despite instillation of an anticoagulant lock solution, an alternative approach is to coat the surface of the catheter with heparin. Preliminary short-term observations suggest that heparin-coated catheters are less thrombogenic than noncoated catheters (3). However, there are no published clinical studies comparing the long-term patency of heparin-coated and noncoated catheters in hemodialysis patients.Bacteremia is the second major complication of dialysis catheters. It arises from the bacterial biofilm that forms on the inner surface of the catheter after its insertion in the central vein (4). Catheter-related bacteremia is treated with systemic antibiotics in conjunction with catheter removal, guidewire catheter exchange, or instillation of an antibiotic lock into the catheter lumen after each dialysis session (1). The intraluminal thrombus acts as a nidus for the catheter biofilm, and in vitro studies have shown decreased adherence of bacteria to heparin-coated catheters compared with noncoated catheters (5). Moreover, two randomized clinical trials in hospitalized patients with short-term, nontunneled central vein catheters found a lower risk of catheter-related bacteremia in patients with heparin-coated catheters (5,6).The goal of this study was to determine whether heparin-coated dialysis catheters reduce the risk of catheter dysfunction and infection compared with noncoated catheters.     

Mobility therapy and central or peripheral catheter-related adverse events in an ICU in Brazil

OBJECTIVE:

To determine whether mobility therapy is associated with central or peripheral catheter-related adverse events in critically ill patients in an ICU in Brazil.

METHODS:

A retrospective analysis of the daily medical records of patients admitted to the Clinical Emergency ICU of the University of São Paulo School of Medicine Hospital das Clínicas Central Institute between December of 2009 and April of 2011. In addition to the demographic and clinical characteristics of the patients, we collected data related to central venous catheters (CVCs), hemodialysis (HD) catheters and indwelling arterial catheters (IACs): insertion site; number of catheter days; and types of adverse events. We also characterized the mobility therapy provided.

RESULTS:

Among the 275 patients evaluated, CVCs were used in 49%, HD catheters were used in 26%, and IACs were used in 29%. A total of 1,268 mobility therapy sessions were provided to patients while they had a catheter in place. Catheter-related adverse events occurred in 20 patients (a total of 22 adverse events): 32%, infection; 32%, obstruction; and 32%, accidental dislodgement. We found that mobility therapy was not significantly associated with any catheter-related adverse event, regardless of the type of catheter employed: CVC-OR = 0.8; 95% CI: 0.7-1.0; p = 0.14; HD catheter-OR = 1.04; 95% CI: 0.89-1.21; p = 0.56; or IAC-OR = 1.74; 95% CI: 0.94-3.23; p = 0.07.

CONCLUSIONS:

In critically ill patients, mobility therapy is not associated with the incidence of adverse events involving CVCs, HD catheters, or IACs.     

Rapid diagnosis of intravascular catheter-related sepsis

The use of Gram-stained "impression smears" of the external surface of intravascular catheters for rapid detection of catheter-associated infection was studied. Gram's stain results of 322 catheters were correlated with clinical episodes of systemic sepsis and semiquantitative cultures of the catheters. Organisms were seen on Gram's stain of 82 catheters, 37 of which were positive on semiquantitative cultures (greater than or equal to 15 colonies per plate). Catheter-related bacteremia occurred on three occasions. All three catheters showed numerous organisms on Gram's stain, although one was negative on semiquantitative culture. All five catheters, in place during bacteremic episodes that were unrelated to catheter infection, were negative on Gram's stain. If the presence of any organisms on Gram's stain was taken as a positive test result, the sensitivity of Gram's stain in predicting the result of semiquantitative culture was 83%, the specificity was 81%, and the predictive value of a positive and negative culture was 44% and 96%, respectively. Slides took two to five minutes to examine microscopically. Gram-stained impression smears of intravenous catheters can be made by a simple, inexpensive, and rapid technique that is accurate in diagnosing catheter-related infection. However, in this study in which a relatively low prevalence of catheter-related bacteremia occurred, the positive predictive value of the Gram's stain result in the diagnosis of catheter-related bacteremia, in contrast to catheter colonization, was low. Only in a patient group with a high prevalence of catheter-related bacteremia would the test be likely to have a high positive predictive value. Thus, selectivity should be exercised in the application of this method.