The antimicrobial efficacy of a new central venous catheter with long-term broad-spectrum activity

Indwelling vascular catheters are a major cause of nosocomial sepsis. Prevention of colonization of polymeric surfaces by continuous release of bactericidal, highly biocompatible antimicrobials incorporated into polymers has been investigated as a promising new approach. An antimicrobial polyurethane catheter was investigated by HPLC and various antimicrobial assays. Controlled drug delivery governed by the physico-chemical mass transfer from the polyurethane bulk provided long-term release of the antimicrobial substances from the material to the outer surface and catheter lumen. The in vitro activity of catheters coated with miconazole and rifampicin against 158 clinical isolates of catheter-associated infections was evaluated. Incubated in physiological NaCl at 37 degrees C, the half-life of inhibitory activity of catheters coated with miconazole or rifampicin exceeded 3 weeks. In static and dynamic adhesion assays, coated catheters were able to prevent colonization with Staphylococcus aureus, Staphylococcus epidermidis and enterococci. To produce catheters resistant to infection, a potent antimicrobial efficacy combined with an excellent biocompatibility over time is needed. The long lasting efficacy of the antimicrobial polyurethane alloy as well as the increased antifungal activity of miconazole combined with rifampicin may be regarded as a promising improvement for long-term central venous access.     

Prolonged antimicrobial activity of a catheter containing chlorhexidine-silver sulfadiazine extends protection against catheter infections in vivo

The present study evaluated in vitro and in vivo a new chlorhexidine (C)-silver sulfadiazine (S) vascular catheter (the CS2 catheter) characterized by a higher C content and by the extended release of the surface-bound antimicrobials. The CS2 catheter was compared with a first-generation, commercially available CS catheter (the CS1 catheter). The CS2 catheter produced slightly smaller zones of inhibition (mean difference, 0.9 mm [P < 0.001]) at 24 h against Staphylococcus aureus and five other microorganisms by several different methodologies. However, in a rabbit model, both CS catheters were similarly efficacious in preventing a catheter infection when the rabbits were inoculated with 10(4) to 10(7) CFU of S. aureus at the time of catheter insertion. The CS2 catheter retained its antimicrobial activity significantly longer in vitro and in vivo (half-lives exceeded 34 and 7 days, respectively) and was also significantly more efficacious in preventing a catheter infection when 10(6) CFU of S. aureus was inoculated 2 days after catheter implantation (P < 0.001). These results suggest that prolonged anti-infective activity on the external catheter surface provides improved efficacy in the prevention of infection.     

Clinical evaluation of elastomeric hydrogel peripheral catheters during home infusion therapy

The use of elastomeric hydrogel (Aquavene, Menlo Care, Menlo Park, Calif.) peripheral catheters in home infusion therapy was prospectively evaluated. Elastomeric hydrogel catheter composition differs from that of conventional peripheral catheters made of Teflon or silicone in that it softens upon insertion and expands two gauge sizes within 30 minutes of insertion. Fifty-four test catheters were successfully placed in 44 home infusion therapy patients, for a total dwell time of 290 days. Average dwell time was 5.37 days, with a range of 1 to 20 days. The extension of dwell time beyond the accepted standard of 72 hours was not associated with an increased incidence of phlebitis when compared to the incidence of phlebitis reported in the scientific literature. The ability to extend peripheral catheter dwell time without increasing the incidence of catheter-related complications may have major clinical and economic advantages for the payors, providers, and consumers of home infusion therapy.     

Incidence of catheter-associated bloodstream infection after introduction of minocycline and rifampin antimicrobial-coated catheters in a pediatric burn population

The Centers for Disease Control and Prevention guidelines for prevention of intravascular catheter-related infections suggest that antimicrobial-coated catheters can decrease the risk of developing catheter-related bloodstream infection in a variety of adult patient populations. There are limited data on their efficacy in the pediatric population, particularly among children with burn injuries. A study was conducted at Shriners Hospitals for Children?, Boston, to determine whether minocycline/rifampin (MR)-coated catheters could decrease the incidence of catheter-associated bloodstream infection (CABSI) in a pediatric burn population. A historical control group included all patients with double- or triple-lumen catheters inserted in the 18-month period from January 2006 to June 2007. The study group included all patients with MR antimicrobial double- or triple-lumen catheters inserted in the subsequent 18-month period, July 2007 to December 2008. Data collected included name, age, date of burn/injury, date of admission, percent TBSA area burn injury or other diagnosis, catheter site (subclavian, internal jugular, or femoral), method of insertion (new percutaneous stick or guidewire), type of catheter (double or triple lumen), date inserted, duration of catheter placement (days), and positive blood cultures recovered while the central venous catheter was in place. CABSI was defined using the Centers for Disease Control and Prevention definition of laboratory-confirmed bloodstream infection. There were a total of 66 patients with 252 catheters (1780 catheter days) in the control group and 75 patients with 263 catheters (1633 catheter days) in the study group. Age, percent burn injury, catheter site, and method of insertion were not statistically different between the two groups. The percentage of infected catheters and the rate of infection were significantly different for the two groups, with the MR antimicrobial catheters only half as likely to become infected. In a subset of these patients with catheters in place for more than 4 days, the percentage of infected catheters and rate of infection were also significantly different with results similar to those in the entire group. MR antimicrobial-coated catheters significantly reduced the incidence of CABSI in this pediatric burn population compared with noncoated catheters.     

Cathéters d’épuration extra-rénale aiguë

Acute catheters for renal replacement therapy (RRT) are used for immediate vascular access in ICU patients with acute renal failure. Most acute catheters are made of poly-urethane, but silicone catheters are also available. The primary determinants of catheter blood flow are the diameter of the catheter and its tip placement. The subclavian insertion site should not be used in a patient who may need permanent vascular access. Femoral catheters seem to be associated with a higher risk of bacteremia than internal jugular catheters. Femoral placement demands a longer length catheter (≥20 cm) for a regular blood flow with limited recirculation. In general, catheter blood flow problems that occur early after placement are related to catheter position while those that occur late are related to thrombosis. Following its use, proper flushing and anticoagulation of the catheter with concentrated heparin or citrate will serve to decrease the risk of internal thrombosis.     

Temporary vascular access for extracorporeal therapies.

Central venous catheters provide at the present time the basic and ideal method to perform acute extracorporeal blood purification. Rapid launch of extracorporeal therapy is indicated in two situations: first, renal conditions presenting as a recognized acute organic renal failure (ARF) and acute decompensation of end stage renal disease (ESRD) without permanent vascular access; second, non-renal conditions presenting as urgent clinical situations requiring isolated ultrafiltration for chronic congestive heart failure, plasmapheresis or selective immunoadsorption for immune diseases, cytapheresis for hematological disease, and selective detoxification for certain types of poisoning. Central venous catheters are classified into 2 categories according to the duration of use: temporary catheter (less than 90 days) and permanent catheter (more than 90 days). A temporary catheter, including rigid (polyethylene, teflon) and semirigid (polyurethane) material, is indicated in emergency situations and for short-term use. A permanent catheter, made usually of soft silicone rubber with a subcutaneous anchoring system, has a subcutaneous tunnel and is indicated in medium and long-term use. Catheter design has benefited greatly from technical advances and material hemocompatability. However, catheter-related morbidity still remains high and is associated with an unacceptable incidence rate of infection and/or vein thrombosis. This article covers our present knowledge regarding catheter indications, technical aspects of catheter insertion and care, functional limitation of central venous catheters, and catheter-related complications. It is also our intent to provide the reader with optimal indication and catheter care in order to prevent and reduce the burden of catheter-related morbidity.     

Thrombus formation on the balloon of heparin-bonded pulmonary artery catheters: an ultrastructural scanning electron microscope study

OBJECTIVE: To investigate heparin-bonded pulmonary artery catheters with respect to thrombus formation and platelet aggregation at the balloon and the shaft using a scanning electron microscope in critically ill patients. DESIGN: Prospective study. SETTINGS: Critical care unit and research laboratories. PATIENTS: Pulmonary artery catheters were inserted in critically ill patients (n = 10). INTERVENTIONS: Pulmonary artery catheters were removed after 24, 48, 72, or 120 hrs, and the ultrastructure was investigated in specialized research laboratories. MEASUREMENTS AND MAIN RESULTS: Balloon and shaft were investigated using a scanning electron microscopic technique. Area of thrombus formation was quantified using image analysis. Heparin release of the catheters was measured. The frequency of balloon inflations was investigated in in vitro experiments by inflating catheters different times (0, 10, 20, and 30 times). Twenty-four hours after catheter insertion, scanning electron microscopic images showed thrombus formation and platelet aggregation at the site of the balloon. Seventy-two hours after catheter insertion, a thrombus started to detach. The areas of thrombus formation did not differ, but thrombus organization changed dramatically 72 and 120 hrs after catheter insertion. The shaft was colonized by single cells only. Cracks of the balloon could be observed after 72 hrs, whereas no cracks could be found in in vitro controls. In vitro, heparin release of the pulmonary artery catheters decreased significantly after 24 hrs. CONCLUSIONS: Scanning electron microscopic images of heparin-bonded pulmonary artery catheters demonstrate thrombus formation on the balloon 24 hrs after pulmonary artery catheter insertion, increasing dramatically at 72 and 120 hrs. The shaft was colonized by single cells only. The thrombus size is not significantly different during the observation time, but the grade and quality of thrombus formation differ.     

The incidence of infectious complications of central venous catheters at the subclavian, internal jugular, and femoral sites in an intensive care unit population

OBJECTIVE: The objective was to assess the risk of central venous catheter infection with respect to the site of insertion in an intensive care unit population. The subclavian, internal jugular, and femoral sites were studied. DESIGN: An epidemiologic, prospective, observational study. SETTING: The setting is a well-functioning intensive care unit under a unified critical care medicine division in a university teaching hospital. Critical care medicine attendings and fellows covered on site 17 and 24 hrs per day, respectively. PATIENTS: Patients were critically ill. All patients were triaged into the intensive care unit by on-site critical care medicine fellows. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: In an intensive care unit population, we prospectively studied the incidence of central venous catheter infection and colonization at the subclavian, internal jugular, and femoral sites. The optimal insertion site for each individual patient was selected by experienced intensive care physicians (critical care medicine attendings and fellows). All of the operators were proficient in inserting catheters at all three sites. Confounding factors were eliminated; there were a limited number of experienced operators inserting the catheters, a uniform protocol stressing strict sterile insertion was enforced, and standardized continuous catheter care was provided by dedicated intensive care nurses proficient in all aspects of central venous catheter care.Two groups of patients were analyzed. Group 1 was patients with one catheter at one site, and group 2 was patients with catheters at multiple sites. Group 1 was the primary analysis, whereas group 2 was supporting.A total of 831 central venous catheters and 4,735 catheter days in 657 patients were studied. The incidence of catheter infection (4.01/1,000 catheter days, 2.29% catheters) and colonization (5.07/1,000 catheter days, 2.89% catheters) was low overall.In group 1, the incidence of infection was subclavian: 0.881 infections/1,000 catheter days (0.45%), internal jugular: 0/1,000 (0%), and femoral: 2.98/1,000 (1.44%; p = .2635). The incidence of colonization was subclavian: 0.881 colonization/1,000 catheter days (0.45%), internal jugular: 2.00/1,000 (1.05%), and femoral: 5.96/1,000 (2.88%, p = .1338). There was no statistically significant difference in the incidence of infection and colonization or duration of catheters (p = .8907) among the insertion sites.In group 2, there was also no statistically significant difference in the incidence of infection and colonization among the three insertion sites. CONCLUSION: In an intensive care unit population, the incidence of central venous catheter infection and colonization is low overall and, clinically and statistically, is not different at all three sites when optimal insertion sites are selected, experienced operators insert the catheters, strict sterile technique is present, and trained intensive care unit nursing staff perform catheter care.     

Long-term catheter management: minimizing the problem of premature replacement due to balloon deflation

Balloon deflation in long-term indwelling urinary catheters has been reported, and can necessitate a premature replacement of the catheter. This problem is studied in catheters of various materials and their performance in this respect compared. The catheters are also compared in terms of any change in effective shaft diameter. The results show that 100% silicone catheters perform significantly less well than silicone-coated latex ones on both parameters. The implications of these findings are discussed, and recommendations are made with regard to the selection of catheters for long-term use.     

The challenge of anticipating catheter tip colonization in major heart surgery patients in the intensive care unit: are surface cultures useful?

OBJECTIVE: Patients undergoing heart surgery show a high risk of catheter colonization and catheter-related bloodstream infections. We evaluated whether skin insertion site and catheter hub surveillance cultures ("surface cultures") could predict catheter colonization and help establish the origin of bloodstream infections. DESIGN:: Prospective cohort study. SETTING: An 11-bed heart surgery intensive care unit in a tertiary university hospital. PATIENTS: Heart surgery patients spending >4 days in intensive care over an 11-month period. INTERVENTIONS: All catheters were surveyed. Cultures were obtained from the skin insertion site and all hubs on day 5 after surgery, every 72 hrs thereafter, and on catheter removal. Swabs were processed semiquantitatively by streaking the surface of a Columbia agar plate. Catheters were processed using Maki's method. The observation of > or = 15 colonies/plate was taken to indicate a positive skin or catheter colonization culture result. MEASUREMENTS AND MAIN RESULTS: Over the study period, 561 catheters were inserted in 130 patients. The median time a catheter was in place was 6 days (interquartile range 3-11), and 3,712 surface cultures were obtained (median four per patient). Catheter colonization occurred in 133 catheters, and there were 15 episodes of catheter-related bloodstream infection (incidence density of colonization 29.3 and of catheter-related bloodstream infection 8.8 per 1,000 catheter-days). Validity indexes for the capacity of surface cultures to predict catheter colonization and catheter-related bloodstream infection, respectively, were as follows: accuracy, 71.4, 65.6; sensitivity, 83.5%, 100%; specificity, 67.1%, 64.7%; positive predictive value, 47.6%, 7.2%; negative predictive value, 91.9%, 100%; positive likelihood ratio, 2.5, 2.83; and negative likelihood ratio, 0.2, 0. Surface cultures correctly predicted 77.4% of all bacteremia episodes (catheter-related and non-catheter-related). CONCLUSIONS: Systematic surveillance cultures of catheter hub and skin insertion sites in patients admitted to a heart surgery intensive care unit could help identify patients who would benefit from decontamination and preventive measures and establish whether catheters are the portal of entry of bloodstream infection.     

涤纶环深静脉留置导管在血液透析中的应用

目的 探讨经皮下隧道留置带涤纶环双腔导管作为血液透析长期通路的方法、临床应用效果及并发症的防治.方法 采用Seldinger技术和撕脱型扩张导管法对25例血液透析患者行带涤纶环导管深静脉留置术并观察置管术后相关的并发症;同时以尿素清除指数(Kt/V)、时间平均尿素浓度(TACurea)、蛋白质分解代谢率(nPCR)和尿素下降率(URR)为指标评价透析效果,同期选20例内瘘患者作透析并进行比较.结果 25例患者中,经颈内静脉入路23例(右21例,左2例),颈外静脉及锁骨下静脉各1例.除1例患者脑梗死死亡,其余导管均在使用.出现导管内血栓形成或流量不足4例,经溶栓、导管调整均再通;感染2侧,发生率3.61次/1000导管日,抗感染治疗后炎症消失.25例的平均URR 71.03%,Kt/V 1.29,TACurea 12.74 mmol/L,nPCR0.93 g/(kg·d);与内痿患者[URR 72.46%,Kt/V 1.31,TACurea 12.86 mmol/L,nPCR 0.94 g/(kg·d)]比较差异均无统计学意义(P均>0.05).结论 涤纶环双腔血液透析导管可长期留置,并可保障透析充分;良好的置管技术和并发症防治,可以提高导管的使用效果.     

Improved long-term maintenance of central venous catheters with a new dressing technique

Nursing procedures that may be important for maintaining in-dwelling central venous catheter sterility include the use of occlusive dressings, the frequency of dressing changes, the number and skill of nurses doing the dressing changes, the duration of catheterization, the use of antimicrobial ointment, and the extent to which sterile procedures are used during catheter placement. During a 9-month period, two different methods for applying central venous catheter dressings were compared. A new method designed to improve the stability of the dressing and to reduce tension on the catheter was found to be associated with longer maintenance of the dressings compared with a more traditional dressing; 14% fewer dressings were changed because of loss of occlusiveness. With this dressing technique and a strict protocol, including insertion and maintenance of central venous catheters by a nutritional support team, prolonged (greater than 7 days) maintenance of central venous catheters was found to be possible without an increase in the incidence of infection.     

In vitro comparison of nitrofurazone- and silver alloy-coated foley catheters for contact-dependent and diffusible inhibition of urinary tract infection-associated microorganisms

Two marketed antimicrobial-coated Foley catheters were compared for in vitro diffusible and contact-dependent inhibition of 11 urinary tract infection-associated microorganisms in an adherence-biofilm assay. Nitrofurazone-coated catheters significantly outperformed silver alloy-coated catheters for inhibitory activity, according to both inoculum broth and catheter sonicate counts, whether compared directly or against the corresponding control catheters. Although inhibition waned with catheter preincubation in saline, some organisms were inhibited even after a 48-h catheter preincubation, especially by the nitrofurazone-coated catheter.     

The prognostic significance of the ball-valve effect in Groshong catheters

The aim of the work was to determine the prognostic significance of the ball-valve effect (BVE) in a population of adult cancer patients with long-term indwelling Groshong catheters. A prospective longitudinal study of 356 Groshong catheters utilized for long-term central venous access was carried out in adult oncology patients. A subset analysis was undertaken of those catheters that developed BVE. BVE was the most commonly identified impediment to normal catheter function, comprising 30% of all identified complications (119/397). BVE was also the most frequent de novo (primary) complication (85 of 221, 38.5%), as well as the complication that occurred soonest in the life of the catheter (average=61.2 days after insertion). Patients with BVE were likely to develop subsequent catheter-related venous thrombosis (20 of 30 compared to 65 of 191,P<0.01), but no other significant catheter-related complication. Patients more than 65 years old had an increased incidence of BVE as the primary complication (46 of 85 compared to 49 of 136,P=0.01), while patients with breast cancer had a lower incidence (12 of 85 compared to 36 of 136,P=0.04). No catheter was removed as a result of the development of BVE. The onset of BVE represents an elemental perturbation of catheter function which portends the development of other, more significant vascular occlusive complications. Phenomenologically, BVE has been overshadowed in significance by the clinically more dramatic venous thrombosis and catheter-related infections. The true significance of BVE can not be determined until the impact of preventing this early complication on the incidence of secondary complications is analyzed prospectively.This study was supported in part by Bard Access Systems, Salt Lake City, Utah     

Percutaneous Peritoneal Dialysis Catheter Insertion by a Nephrologist: A New,Simple, and Safe Technique

♦ Background: Insertion of the peritoneal dialysis (PD) catheter by a nephrologist has been encouraged by several studies. The ultimate goal is to provide safe, timely, and effective catheter insertion without an unduly long wait time or delay. The success of PD depends partly on the ease of catheter insertion. We developed a new technique for percutaneous PD catheter insertion by nephrologists. Our new technique, in addition to being easy, proved to be safe and to eliminate the need for the peel-away sheath.♦ Methods: Data were collected prospectively on all patients having a PD catheter inserted by a nephrologist using our new technique (40 catheters in 38 patients). All catheters were evaluated for infectious and mechanical complications.♦ Results: The mean duration of the procedure from skin sterilization to the end of insertion was 24 ± 3 minutes. No bowel perforation or serious hemorrhage was recorded. Poor initial drainage was recorded in 12.5% of the catheters (n = 5) during the 4 weeks after insertion. The incidence of early exit-site leakage was 2.5% (1 catheter). Episodes of exit-site infection occurred in 5.0% and 12.5% of catheters (within 1 month and by the end of study period respectively). Two episodes of peritonitis were reported by the end of the 12-month period. Catheter survival was 95.0% and 87.5% at 6 months and 12 months respectively.♦ Conclusions: Percutaneous bedside placement of PD catheters using our new technique is safe and carries less morbidity in terms of bowel perforation, catheter-related infection, and exit-site leak. In addition, our new technique appears to have a high success rate and to offer considerable savings in terms of operating time.     

Catheter-related bloodstream infections in intensive care units: a systematic review with meta-analysis

Title. Catheter‐related bloodstream infections in intensive care units: a systematic review with meta‐analysis Aim. This paper is a report of a systematic review and meta‐analysis of strategies, other than antimicrobial coated catheters, hypothesized to reduce risk of catheter‐related bloodstream infections and catheter colonization in the intensive care unit setting. Background. Catheter‐related bloodstream infections occur at a rate of 5 per 1000 catheter days in the intensive care unit setting and cause substantial mortality and excess cost. Reducing risk of catheter‐related bloodstream infections among intensive care unit patients will save costs, reduce length of stay, and improve outcomes. Methods. A systematic review of studies published between January 1985 and February 2007 was carried out using the keywords ‘catheterization – central venous’ with combinations of infection*, prevention* and bloodstream*. All included studies were screened by two reviewers, a validated data extraction instrument was used and data collection was completed by two blinded independent reviewers. Risk ratios for catheter‐related bloodstream infections and catheter colonization were estimated with 95% confidence intervals for each study. Results from studies of similar interventions were pooled using meta‐analyses. Results. Twenty‐three studies were included in the review. The strategies that reduced catheter colonization included insertion of central venous catheters in the subclavian vein rather than other sites, use of alternate skin disinfection solutions before catheter insertion and use of Vitacuff in combination with polymyxin, neomycin and bacitracin ointment. Strategies to reduce catheter‐related bloodstream infection included staff education multifaceted infection control programmes and performance feedback. Conclusion. A range of interventions may reduce risks of catheter‐related bloodstream infection, in addition to antimicrobial catheters.     

硅胶材质PICC导管破损的修复新方法

目的:探讨新型方法修复断裂的BD PICC导管。方法:选择导管破损患者2例,导管送管困难患者3例,在无菌操作下,将断裂的原导管轻轻向外拖移3 cm,用无菌剪刀将破裂导管尾部剪去,先将巴德导管末端连接器的减压套筒穿过留在体外的导管,然后再将导管与针芯柄对扣锁住。结果:2例导管破损患者使用该方法成功修复,在后续使用中均未出现漏液、脱落、堵管、感染。2例使用时间超过210 d,现仍在带管中。3例因送管困难患者中,1例留置216 d,后因死亡拔管;2例留置30 d拔管。结论:该种修复方法安全有效,值得临床推广应用。     

Antibiotic releasing polymers

Catheters with two different antibiotic coating systems were evaluated. The first was a simple coating of an antibiotic (dicloxacillin) complexed with a quaternary amine. The second combined the latter with a polyurethane matrix. Both were coated onto polyurethane catheter substrates for testing. The objective of such systems is to deliver prophylactic antibiotic in high concentrations to the vascular access entry site and to the surrounding microenvironment of the insertion tunnel.By using a Kirby-Bauer technique and measuring inhibition zone size, it was found that both coating systems were effective in inhibiting Staphylococcus aureus. However, the half-life of the catheter antibiotic activity for the antibiotic-polymer matrix was 100% longer (24 h vs. 12 h) than the simple antibiotic-complex coated catheters. In vivo subcutaneous mouse model studies confirmed in vitro results of antimicrobial inhibition. These studies suggest that antibiotic releasing vascular access devices can decrease the potential for vascular access site infections.     

Colonization and infection of pulmonary artery catheter in cardiac surgery patients: epidemiology and multivariate analysis of risk factors

OBJECTIVE: To assess the incidence and etiology of colonization and infection of pulmonary artery catheters inserted in cardiac surgery patients. To determine the influence of some variables on the risk of developing pulmonary artery catheter colonization and infection. DESIGN: Prospective observational study of pulmonary artery catheters inserted into the internal jugular vein that were in place for >48 hrs over a 13-month period. Data collected included age, gender, nature of the cardiac surgery intervention, duration of extracorporeal circulation, date of insertion and removal, subsequent infection, and curative antimicrobial therapy. End points were pulmonary artery catheter colonization with >or=10(3) colonies on quantitative cultures and pulmonary artery catheter-related bacteremia. Risk factors for colonization were determined by multiple logistic regression. SETTING: A 17-bed cardiac surgery intensive care unit in a 480-bed teaching hospital in Paris. PATIENTS: Patients undergoing cardiac surgery procedures between May 1, 1997, and May 31, 1998. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 164 pulmonary artery catheters inserted in 157 patients, 19 (11.6%) and 1 (0.6%) were associated with colonization (mean duration of catheterization, 7.5 +/- 2.8 days) and bacteremia, respectively. These data represent an incidence of 17.7 and 0.93 episodes per 1000 catheterization-days, respectively. Pulmonary artery catheter colonization was caused by Gram-positive cocci in 48% (67% were coagulase-negative staphylococci), Gram-negative rods in 48%, and Candida albicans in 4%. From multivariate analysis, >4 days of catheterization was the single variable associated with a significantly increased risk of pulmonary artery catheter colonization (odds ratio, 9.81; 95% confidence interval, 1.24-77.5, p = .03). CONCLUSIONS: Our data show that the risk of pulmonary artery catheter-related colonization and bacteremia is quite low despite the use of a high-risk insertion site. In cardiac surgery patient populations, a trial evaluating the impact of a systematic pulmonary artery catheter removal after 4 days is warranted.     

Evaluation of strategies for central venous catheter replacement.

OBJECTIVES: To assess the consequences of leaving a bacterially colonized central venous catheter in place and to compare the effects of three catheter replacement strategies for catheter repair control in an animal model. DESIGN: Prospective study. SETTING: Laboratory and animal facility of a large university. SUBJECTS: Eighteen healthy, female, adult sheep. INTERVENTIONS: Radiopaque-siliconized elastomer central venous catheters were inserted into the jugular veins and colonized with either Escherichia coli or Staphylococcus epidermidis. After 7 days of infection, the catheters were either: a) exchanged using a guidewire; b) removed and replaced with a new catheter in a new jugular vein site after a 48-hr interval; or c) exchanged using a guidewire and antibiotics (tobramycin, cephaloridine) injected into the catheter. Animals were euthanized 7 days after insertion of the new catheter. Quantitative microbiology was performed on blood samples collected daily from the catheters and a peripheral vein, as well as from catheters and tissue recovered from the sheep at the time of autopsy. MEASUREMENTS AND MAIN RESULT: When catheters were changed using a guidewire, they became colonized by bacteria within 48 hrs, and the sheep had embolic pneumonia and vegetative endocarditis at autopsy. Similar consequences were observed when antibiotics were administered into the catheter lumen. If colonized catheters were removed and a new catheter was inserted after a 48-hr interval, recolonization, pneumonia, and endocarditis were not observed. CONCLUSIONS: Replacement of a biofilm-colonized central venous catheter over a guidewire is associated with rapid colonization of the replacement catheter and production of detached, slime-enclosed, antibiotic-resistant aggregates that colonize other catheters or initiate endocarditis or pneumonia by dissemination in the bloodstream.