Dialysis Central Venous Catheter Types and Performance

Multi-Functional Biomaterial for the Treatment and Prevention of Central Line-Associated Bloodstream Infections

Central venous catheters are among the most used medical devices in hospitals today. Despite advances in modern medicine, catheter infections remain prevalent, causing significant morbidity and mortality worldwide. Here, SteriGel is reported, which is a multifunctional hydrogel engineered to prevent and treat central line-associated bloodstream infections (CLABSI). The mechanical properties of SteriGel are optimized to ensure appropriate gelation kinetics, bio-adhesiveness, stretchability, and recoverability to promote durability upon application and to provide persistent protection against infection. In vitro assays demonstrated that SteriGel exhibits long-term antimicrobial efficacy and has bactericidal effects against highly resistant patient-derived pathogens known to be frequently associated with CLABSI. SteriGel outperformed Biopatch, which is a clinically used device for CLABSI, in ex vivo cadaver studies that simulate clinical scenarios. Furthermore, SteriGel has biocompatible, pro-healing, and anti-inflammatory properties in vitro and in a rat subcutaneous injection model, suggesting a potential synergistic effect in the prevention and treatment of CLABSI. SteriGel is a multifunctional adherent biomaterial with potent antimicrobial effects for sustained sterility while promoting healing of the catheter incision site to protect against infection.

The use of Hub Devices to reduce catheter-related infections in dialysis patients: A narrative review

INTRODUCTION

Catheter-related bloodstream infections are among the most critical issues associated with central venous catheters used for dialysis treatment. To reduce the incidence of this life-threatening complication, various strategies have been developed. Among these, Hub Devices have been introduced in clinical practice to prevent microbial growth at the hub of the catheter.

METHODS

A review was conducted to assess the effectiveness of Hub Devices in reducing bloodstream infections in central venous catheters for dialysis, compared to solid caps. The review analyzed existing literature from three bibliographic databases (PubMed, Embase, and CINAHL) to provide evidence-based recommendations for clinical practice.

RESULTS

After a thorough review of the available data, it was found that out of the 873 records screened, only six trials met the inclusion criteria. Albeit the number of patients observed in these trials was more than 25,000, due to the differences in the mechanism of action of different Hub Devices and the lack of a standardized criterion to identify and measure the outcomes, it is difficult to draw a firm conclusion. It is worth noting, however, that in five out of six trials examined, the Hub Devices exhibited a protective effect when compared to solid caps.

CONCLUSIONS

The use of Hub Devices appears to be associated with a reduction in catheter-related bloodstream infections in the central venous catheter dialysis population. However, the Hub Devices show interesting results that should be investigated with further well-designed prospective studies.

Recent developments in preventing catheter-related infections based on biofilms: A comprehensive review

Urinary and vascular catheters are among the most commonly used medical devices. However, infections caused by biofilm formation on the surface of catheters are a major cause of healthcare-associated infections. Traditional methods, such as using antimicrobials to prevent such infections, generally have short-term effects, and treatment is challenging owing to the emergence of antimicrobial-resistant bacteria. This review aims to evaluate the limitations of conventional catheter-related infection prevention efficacy, such as currently used antimicrobials, and analyze the efficacy and limitations of potential alternatives to prevent catheter-related infections that have not yet been commercialized, classified by the transition stages of biofilm formation. We intend to provide profound insights into the ideal technologies for preventing catheter-associated tract infections and present perspectives on future directions in this field.

Bioinspired super-hydrophilic zwitterionic polymer armor combats thrombosis and infection of vascular catheters

Thrombosis and infection are two major complications associated with central venous catheters (CVCs), which significantly contribute to morbidity and mortality. Antifouling coating strategies currently represent an efficient approach for addressing such complications. However, existing antifouling coatings have limitations in terms of both duration and effectiveness. Herein, we propose a durable zwitterionic polymer armor for catheters. This armor is realized by pre-coating with a robust phenol-polyamine film inspired by insect sclerotization, followed by grafting of poly-2-methacryloyloxyethyl phosphorylcholine (pMPC) via in-situ radical polymerization. The resulting pMPC coating armor exhibits super-hydrophilicity, thereby forming a highly hydrated shell that effectively prevents bacterial adhesion and inhibits the adsorption and activation of fibrinogen and platelets in vitro. In practical applications, the armored catheters significantly reduced inflammation and prevented biofilm formation in a rat subcutaneous infection model, as well as inhibited thrombus formation in a rabbit jugular vein model. Overall, our robust zwitterionic polymer coating presents a promising solution for reducing infections and thrombosis associated with vascular catheters.

Evaluating Short-Term Outcomes of Tunneled and Non-Tunneled Central Venous Catheters in Hemodialysis

Background: The necessity of using central venous catheters (CVCs) in hemodialysis, coupled with their associated complications, remains a critical concern in nephrology. This study aims to compare the short-term prognosis of tunneled (T-CVC) and non-tunneled (NT-CVC) CVCs in acute hemodialysis patients, specifically focusing on infection rates, malpositioning, and lumen thrombosis within the first three weeks post-insertion. Methods: A retrospective analysis was conducted on 176 CVCs placed between January and December 2023 at the Policlinico di Modena and the Ospedale Civile di Baggiovara. Patient demographics, CHA2DS2-VASc scores, and comorbid conditions were recorded at the time of catheter placement. Outcomes assessed included catheter-related infections, malpositioning, and lumen thrombosis. Statistical analyses, including Chi-square tests, Fisher's exact tests, and Kaplan-Meier survival analysis, were performed to evaluate differences between T-CVCs and NT-CVCs. Results: The sample comprised 43% females with a mean age of 69.3 years (SD 13.9) and a mean CHADS-VASC score of 3.72 (SD 1.4). Hypertension (90%) was the most prevalent comorbidity. Of the 176 CVCs, 127 were T-CVCs and 49 were NT-CVCs. Infection rates were 3.15% for T-CVCs and 8.16% for NT-CVCs (p = 0.07). Malpositioning occurred in 0.79% of T-CVCs and 4.08% of NT-CVCs (p = 0.47). There was one case of lumen thrombosis in the NT-CVC group. Kaplan-Meier analysis indicated a significant divergence in infection-related catheter survival favoring T-CVCs after ten days (p = 0.034). Conclusions: While non-tunneled CVCs do not significantly alter short-term prognosis compared to tunneled CVCs, the latter show a better infection-related survival rate beyond ten days. Therefore, primary insertion of T-CVCs may be preferable when resources and clinical conditions permit, although NT-CVCs remain a viable option when immediate T-CVC insertion is challenging.

Preventing healthcare-associated MRSA bacteremia: getting to the root of the problem

Introduction

Bloodstream infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remain a major challenge in most countries worldwide.

Setting

We describe a quasi-experimental sequential intervention at Mater Dei Hospital, Malta, to reduce hyper-prevalence of healthcare-associated MRSA bacteremia (HA-MRSA-B).

Interventions

The hospital initiated a hand hygiene (HH) campaign in 2008 to improve alcohol hand rub (AHR) use. In 2011, this was followed by root cause analysis (RCA) of all HA-MRSA-B cases and finally universal MRSA admission screening in 2014. Change-point analysis was used to evaluate the impact of the interventions.

Results

The effect of the HH campaign became evident when AHR consumption reached 40 L/1000 occupied bed days (BD). RCAs identified intravascular devices as the likely risk factor in 83% of all HA-MRSA-B; specifically non-tunneled double-lumen hemodialysis catheters (36%), peripheral venous cannulas (25%), and central venous catheters (22%). Interventions to improve their management resulted in the greatest reduction of HA-MRSA-B rates. They were informed by the RCA findings and targeted behavior change through education, motivation, and system change. Universal MRSA admission screening provided the final decline in incidence. Each intervention affected HA-MRSA-B rates after a lag period of approximately 18-24 months. Overall, HA-MRSA-B incidence decreased from 1.72 cases/10000BD in 2008 to 0.18/10000BD in 2019; a reduction of almost 90%. Intravenous device interventions were also associated with a reduction of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia rates.

Conclusions

Significant improvement in HA-MRSA-B is possible, even in highly endemic regions. It requires well-planned behavior change interventions which are compatible with local context and culture.

Non-tunneled catheter tip depth position in urgent hemodialysis: a randomized controlled trial

BACKGROUND

The average accepted depth for non-tunneled catheters (NTC) insertion does not guarantee its correct position, so controversy exists. The aim of this study was to assess the effect of two NTC placement depths on the number of NTC complication episodes.

METHODS

We designed a triple blind, parallel group, randomized controlled trial in a single Hemodialysis Center in Mexico (Registry: ACTRN12619000774123). We included patients in urgent need of hemodialysis via internal right jugular vein NTC. The length of the NTC tip placement depth was randomized to second intercostal space (2ICS) or fourth intercostal space (4ICS), using physical landmarks. The primary outcome was to compare the composite number of NTC dysfunction, repositioning, and relocation episodes for 48 hours post-procedure.

RESULTS

One hundred and sixty-five patients were included, 86 and 79 patients to NTC placement in the 2ICS and 4ICS, respectively. All patients underwent intention-to-treat analysis. The incidence of the composite outcome was lower in the 2ICS group compared to the 4ICS group, 4 (4.6%) and 50 (63%) combined episodes, respectively (P<0.001). Compared to the 4ICS group, the 2ICS group presented a relative risk of 0.06 (CI: 0.02-0.21, P<0.001) and number needed to treat (NNT) of 2.1. No adverse events occurred, derived from the NTC placement.

CONCLUSIONS

NTC tip placement in the 2ICS compared to 4ICS decreases the incidence of the combined number of dysfunctions, repositioning and relocation episodes, with a NNT of 2 for its prevention.

Two cases of aseptic internal jugular vein thrombophlebitis associated with hemodialysis catheter, presenting as sore throat: case report and literature review

Background

Non-cuffed hemodialysis (HD) catheters are often used for emergency or temporary vascular access. Its complications include thrombosis and catheter-related bloodstream infection (CRBSI); however, thrombophlebitis can also occur. Thrombophlebitis of the internal jugular vein (IJV) may present with symptoms, such as fever, lateral neck pain, and swelling, regardless of the presence or absence of infection; however, symptoms may be minor and easily overlooked. Sore throat is a well-known symptom of Lemierre's syndrome, but has not been reported in cases of thrombophlebitis without infection. We report two cases of HD catheter-associated IJV thrombophlebitis in patients that were diagnosed with sore throat.

Case presentation

Case 1 included a 58-year-old woman with diabetic nephropathy on HD. She was admitted to our hospital due to the occlusion of an arteriovenous fistula (AVF) for dialysis. A temporary HD catheter was placed in the right IJV until an arteriovenous graft (AVG) was fabricated. After admission, CRBSI was suspected because she developed fever; however, bacteremia was ruled out and a sore throat gradually developed. Contrast-enhanced computed tomography (CT) revealed thrombophlebitis of the right IJV. Anticoagulation therapy was initiated and she was discharged due to an improvement of symptoms. Case 2 included an 83-year-old man with end-stage renal disease due to hypertensive nephrosclerosis. He was admitted to our hospital because of AVF occlusion. A temporary HD catheter was inserted into the right IJV and an AVG was created. He had elevated C-reactive protein levels after catheter placement but was asymptomatic. When removing the catheter, he complained of throat discomfort. Ultrasonography of the neck revealed thrombotic obstruction of the right IJV, and contrast-enhanced CT revealed thrombophlebitis of the right IJV. Blood culture results were negative. He was discharged after anticoagulation therapy was started and symptoms improved.

Conclusions

The presence of sore throat leads to the diagnosis of IJV thrombophlebitis. Pharyngeal symptoms that develop after central venous catheter (CVC) placement should be differentiated from thrombophlebitis using a minimally invasive vascular ultrasound.

Nationwide practices in the use of central venous catheters for therapeutic plasma exchange in the inpatient setting

INTRODUCTION

Therapeutic plasma exchange (TPE) is often impacted by difficulties in obtaining an adequate and safe vascular access. This study evaluated the rates, predictive factors, and clinical outcomes associated with central venous catheter (CVC) use during the inpatient TPE procedures.

METHODS

The Nationwide Readmissions Database, 2016 to 2017 was used to identify hospitalizations with TPE with and without CVC insertion.

RESULTS

During the study period, there were 35 429 hospitalizations with TPE (pediatric 6.1%, mean ± standard deviation (SD) age 50.9 ± 20.0 years, female 52.7%). CVC insertion was documented in 24 414 (73.4%) adult and 1596 (73.5%) pediatric hospitalizations. In pediatric patients, age >15 years, higher disease severity, and private insurance were associated with higher odds of CVC insertion. In adults, female sex, obesity, concurrent hemodialysis, and higher disease severity were associated with CVC insertion. Adults with private insurance and both adult and pediatric hospitalizations at the teaching hospitals had lower odds of CVC placement. All patients with CVC insertion had longer length of hospital stay, and adults with CVC insertion also had higher hospital charges, higher in-hospital mortality, and lower likelihood of being discharged to home.

CONCLUSION

CVC insertion is performed for the majority of inpatient TPE procedures and CVC use appears to correlate with worse clinical outcomes.

Factors influencing the long-term outcome of tunneled hemodialysis catheters

PURPOSE

To review the incidence and type of tunneled hemodialysis catheter (THC) complications in a large cohort of patients with end-stage renal disease. Additionally, the longevity of the THC and factors predicting high risk for catheter complications were assessed.

MATERIAL AND METHODS

Between August 2009 and December 2016, a cohort of 538 patients underwent primary THC insertion; in 119 patients, THC was inserted after failed arteriovenous fistula or graft. Patients without available clinical follow-up data (n = 67) were excluded for further analysis. The Charlson comorbidity index (CCI) was calculated for each patient. The cumulative incidence function (CIF) was used for THC overall longevity, while Cox proportional hazards models were used for risk factor analysis.

RESULTS

In 352 patients, THC was inserted in a virgin neck. THC-related complications were observed in n = 104 (29.55%) of the patients. Infection occurred in n = 38 (10.80%) and malfunction, related to thrombosis or mechanical damage, in n = 45 (12.78%). Removal of the THC for the purpose of switching to alternative dialysis methods was planned in n = 135 (38.4%). The remaining patients were still alive with a functioning THC (n = 18; 5.11%) or died (n = 95; 27%) with a functioning THC. The THC survival rate was 82.67%, 78.13%, 74.15%, 72.96%, 71.02%, and 70.63% on follow-up after 6 months, and after 1-5 years, respectively. Gender, CCI, age, and site of placement of the catheter were found not to affect the life of the catheter.

CONCLUSION

The overall complication rate in primary inserted THC was nearly 30% and mainly related to infection and malfunction. THC survival was more than 70% after 5 years, which supports its use for permanent dialysis access, irrespective of gender, CCI, age, and jugular side of THC placement.

Mid-term results of tunneled brachial venous hemodialysis catheter placement: Our single-center experience with 21 patients

Background

This study aims to analyze the safety and efficacy of permanent hemodialysis catheter insertion via the brachial vein in unsuitable patients for catheter insertion from other vascular access sites.

Methods

A total of 21 patients (6 males, 18 females; mean age: 54.4±11.3 years; range, 48 to 77 years) who underwent permanent hemodialysis catheter insertion via the brachial vein between February 2019 and February 2020 were retrospectively analyzed. All patients underwent brachial venous tunneled catheter insertion under the ultrasound guidance and under local anesthesia. Transthoracic echocardiography was performed before and six months after catheter insertion. The primary patency rate of the catheter at six months of follow-up, potential associated complications of a permanent hemodialysis catheter including catheter thrombosis and catheter infections, and all-cause mortality rates were recorded.

Results

Catheter removal was required in eight patients (catheter thrombosis, n=5; catheter infection, n=2; and extensive hematoma, n=1). The catheters were patent in the remaining 13 (62%) patients at six months. Mortality occurred in one patient due to bacterial pneumonia. No life-threatening complications including hemothorax or pneumothorax and neurological injury was observed in any of the patients.

Conclusion

Our study results show that brachial venous tunneled catheter placement for hemodialysis can be a safe and valid alternative to catheter insertion from the jugular or subclavian veins for vascular access in patients with end-stage renal disease.

Spontaneous Dislodgement of Tunneled Dialysis Catheters after De Novo versus Over-The-Wire-Exchange Placement

PURPOSE

To evaluate dislodgement of tunneled dialysis catheters (TDCs) in de novo (DN) placement with ultrasound versus over-the-wire exchange (OTWE).

MATERIALS AND METHODS

Data were collected retrospectively on all TDC placements at this institution from 2001 to 2019 and were excluded if no removal date was recorded or if dwell time was more than 365 days. Information on TDC brand, placement, insertion/removal, and removal reason were collected. Multiple logistic regression evaluated factors associated with TDC dislodgement. DN placement and OTWE were compared for rate of dislodgement (generalized estimating equations method) and TDC dwell time (survival analysis).

RESULTS

In total, 5328 TDCs were included with 66% (3522) placed DN and 32% (1727) via OTWE. Mean dwell time was 65 ± 72 days, and dislodgement occurred in 4% (224). TDC dislodgement rates in the DN and OTWE groups were 0.48 and 0.93 per 1000 catheter days, respectively. Brand (Ash Split vs. VectorFlow), placement technique (OTWE vs. DN), laterality (left vs. right), and site (left vs. right internal jugular vein) were significant predictors of dislodgement. OTWE placement exhibited 1.7 times the odds of dislodgement (95% confidence interval, 1.2-2.6; P = .004) compared to DN and had significantly higher probability of dislodgement across time (hazard ratio = 2.0; P < .001) compared to DN. Dislodgement rates for OTWE vs. DN were 8% vs. 3% (3 months), 13% vs. 6% (6 months), and 38% vs. 17% (1 year).

CONCLUSIONS

TDC spontaneous dislodgement rates were significantly and consistently higher after OTWE compared to DN placement. These data support more careful attention to catheter fixation after OTWE placement.

New Directions in Ensuring Catheter Safety

Tunneled dialysis catheters remain the most common vascular access used to initiate hemodialysis. Unfortunately, their use is associated with higher morbidity and mortality when compared with arteriovenous fistulae or grafts. Different types of catheters with different designs and material properties function differently. Additional devices and medications can be used to decrease the rates of infection and thrombosis. The current available tunneled dialysis catheters remain far from the desired goal and innovation in the field of dialysis vascular access remains in dire need.

Long-term vascular access in differently resourced settings: a review of indications, devices, techniques, and complications

Central venous access is frequently essential for the management of many acute and chronic conditions in children. Millions of central venous access devices (CVADs) are placed each year. In this review article, we discuss the indications for long-term vascular access, the types of devices available, the state of the art of central venous cannulation and device placement, and the complications of long-term central venous access. We pay a special attention to the challenges of, and options for long-term central venous access, also those in developing countries, with limited financial, human, and material resources.

Vascular access for therapeutic plasma exchange

Therapeutic plasma exchange is an apheresis modality in which plasma is separated from the blood cellular components ex vivo, discarded, and replaced with an isosmotic fluid (most commonly 5% albumin) to maintain appropriate oncotic pressure in the patient. Therapeutic plasma exchange is used in the treatment of many diseases and indications. The recent seventh edition of the American Society for Apheresis guidelines indicates approximately 72 diseases and 116 indications for which therapeutic plasma exchange may be effective. One of the critical aspects for the successful performance of therapeutic plasma exchange is appropriate vascular access to provide high blood flow for the collection and return phases of the procedure, especially because most patients who need therapeutic plasma exchange will require more than one treatment over days to weeks. This article provides an overview of the characteristics of therapeutic plasma exchange, the clinical diseases and indications that may be treated with therapeutic plasma exchange, and the different types of vascular access employed, with their advantages and disadvantages. The latter may include peripheral venous access and intravascular or implantable access devices, such as arteriovenous grafts and fistulas, central venous catheters, and central venous catheters tunneled with ports.

Numerical Simulation of Hemodynamic Changes in Central Veins after Tunneled Cuffed Central Venous Catheter Placement in Patients under Hemodialysis

The tunneled central venous catheter (CVC) plays an important role for hemodialysis patients, but CVC-related thrombosis in the central veins remain problematic. This study is the first try to numerically find out what hemodynamic parameters are predisposed to the initiation and formation of thrombus after CVC insertion. And the potential relationship between hemodynamic parameters and the incidence rates of thrombosis occurrence was explored. The results revealed that the CVC insertion led to a significant increase of hydraulic resistance, wide-ranging abnormally high wall shear stress (WSS), and a great loss of flow rotation in the vein. Moreover, the clinical data showed that thrombosis mainly occurred at sections where most blood flow lost spiral rotation after the CVC insertion, but no corresponding match was observed between the occurrence of thrombosis and the flow velocity or WSS. We speculate that the destruction of the flow rotation in the central vein is a precursor to the thrombus formation around CVC, and an introduction of spiral flow with the CVC insertion may possibly help to protect the central vein from thrombosis. Further animal and clinical experiments should be carried out to test and verify this speculation.

Chitosan-based coatings in the prevention of intravascular catheter-associated infections

Central venous access devices play an important role in patients with prolonged intravenous administration requirements. In the last years, the coating of these devices with bactericidal compounds has emerged as a potential tool to prevent bacterial colonization. Our study describes the modification of 3D-printed reservoirs and silicone-based catheters, mimicking central venous access devices, through different approaches including their coating with the well known biocompatible and bactericidal polymer chitosan, with the anionic polysaccharide alginate; also, plasma treated surfaces were included in the study to promote polymer adhesion. The evaluation of the antimicrobial action of those surface modifications compared to that exerted by a model antibiotic (ciprofloxacin) adsorbed on the surface of the devices was carried out. Surface characterization was developed by different methodologies and the bactericidal effects of the different coatings were assayed in an in vitro model of Staphylococcus aureus infection. Our results showed a significant reduction in the reservoir roughness (≤73%) after coating though no changes were observed for coated catheters which was also confirmed by scanning electron microscopy, pointing to the importance of the surface device topography for the successful attachment of the coating and for the subsequent development of bactericidal effects. Furthermore, the single presence of chitosan on the reservoirs was enough to fully inhibit bacterial growth exerting the same efficiency as that showed by the model antibiotic. Importantly, chitosan coating showed low cytotoxicity against human keratinocytes, human lung adenocarcinoma epithelial cells, and murine colon carcinoma cells displaying viability percentages in the range of the control samples (>95%). Chitosan-based coatings are proposed as an effective and promising solution in the prevention of microbial infections associated to medical devices.

A prospective comparison of the performance and survival of two different tunnelled haemodialysis catheters: SplitCath® versus DuraMax®

BACKGROUND

Despite their well-recognised shortcomings, haemodialysis catheters (HDCs) remain an important form of haemodialysis access for many patients. There are several HDCs commercially available, each differing considerably in design, which is known to significantly influence performance and survival. We sought to determine which of two tunnelled HDCs, DuraMax® (Angiodynamics, NY, USA) or SplitCath® (MedComp, PA, USA) delivers the best performance, safety and reliability for dialysis patients.

METHODS

Eighty-six patients were prospectively randomised to receive either DuraMax® (DM) or SplitCath® (SC). Outcomes included: (i) mean flow rates (mL/min) averaged over the first 10 weeks of dialysis, and urea reduction ratio (URR); and (ii) long-term catheter survival with appraisal of any events leading to catheter dysfunction and early removal.

RESULTS

Median flow rates (interquartile range) in the DM and SC groups were 321 (309-343) and 309 (294-322) mL/min, respectively (p = 0.002). URR values for the DM and SC groups were 71 (65-76) and 74 (70-78), respectively, (p = 0.094). There was no significant difference in long-term survival or frequency of incidents that required early HDC removal (9/43 in the DM group, 5/43 patients SC). A slightly higher incidence of HDC dislodgement was noted in the DM group, although this study was not statistically powered to determine its significance.

CONCLUSIONS

We conclude that DM yields slightly higher flow rates in the first 10 weeks of dialysis, and a similar low incidence of complications and long-term survival for both DM and SC HDCs.

Device thrombosis and pre-clinical blood flow models for assessing antithrombogenic efficacy of drug-device combinations

Thrombosis associated with blood-contacting devices is a complex process involving several component interactions that have eluded precise definition. Extensive investigations of individual biological modules such as protein adsorption, coagulation cascade activation and platelet activation/adhesion/aggregation have provided an initial foundation for developing biomaterials for blood-contacting devices, but a material that is intrinsically non-thrombogenic is yet to be developed. The well-recognized association between fluid dynamics parameters such as shear stress, vortices, stagnation and thrombotic processes such as platelet aggregation and coagulation aggravate thrombosis on most device geometries that elicit these flow disturbances. Thus, antithrombotic drugs that were developed to treat thrombosis associated with vascular diseases such as atherosclerosis have also been adapted to mitigate the risk of device thrombosis. However, balancing the risk of bleeding with the antithrombotic efficacy of these drugs continues to be a challenge, and surface modification of devices with these drug molecules to mitigate device thrombosis locally has been explored. Pre-clinical blood flow models to test the effectiveness of these drug-device combinations have also evolved and several in-vitro, ex-vivo, and in-vivo test configurations are available with their attendant merits and limitations. Despite considerable efforts toward iterative design and testing of blood contacting devices and antithrombogenic surface modifications, device thrombosis remains an unsolved problem.

Optimization of Dialysis Catheter Function

Central venous catheters (CVCs) are essential in the management of hemodialysis patients, but they also carry unintended negative consequences and in particular thrombosis and infection, adversely affecting patient morbidity and mortality. This review will focus on the etiology, prevention, and management of CVC-related dysfunction, which is mainly associated with inadequate blood flow. CVC dysfunction is a major cause of inadequate depuration. Thrombus, intraluminal and extrinsic, as well as fibrous connective tissue sheath (traditionally indicated as fibrin sheath) formation play a central role in establishing CVC dysfunction. Thrombolysis with urokinase or recombinant tissue plasminogen activator (rTPA) can be undertaken in the dialysis unit, restoring adequate blood flow in most patients, preserving the existing catheter, and avoiding an interventional procedure. If thrombolytics fail, mainly because of the presence of fibrous connective tissue sheath, catheter exchange with fibrin sheath disruption may be successful and preserve the venous access site. Prevention of CVC dysfunction is important for containing costly pharmacologic and interventional treatments, which also affect patients’ quality of life. Prevention is based on the use of anticoagulant and/or thrombolytic CVC locks, which are only partially effective. Chronic oral anticoagulation with warfarin has also been proposed, but its use for this indication is controversial and its overall risk-benefit profile has not been clearly established.

[Technical criteria of central venous catheters: Anaesthesiologist/intensivist and pharmacist opinions]

INTRODUCTION

The lack of technical information from suppliers and from the literature, a wide variety of features and the absence of medical device reference document explain the difficulty for medical and pharmaceutical staffs to choose a central venous catheter (CVC). The aim of this study was to establish the specifications to choose a CVC according to the clinician needs.

METHODS

An analysis of suppliers' technical documentation and a literature review was performed to identify criteria and to collect them in a questionnaire to conduct semi-structured interviews between 1 pharmacist and 5 anaesthesiologists/intensivists. With these interviews, the technical criteria were classified according to their importance in 3 levels.

RESULTS

Thirteen technical criteria were identified after reading the technical documents and the literature. Among them, 8 were classified as "essential criteria" (level I) by the physicians: J-shaped guide, one clamp on each way, identified lumen, radiopacity, graduation every centimeter by 5 to 20 cm from the distal extremity, a length of 15 to 25 cm, a single-lumen catheter with a 14 to 16G way and a three-lumen catheter with 14 to 18G way. Finally, three criteria were classified as "intermediate criteria" (level II) and two as "optional criteria" (level III).

CONCLUSIONS

This collaborative approach allowed to reference new medical devices according to the clinicians needs. These CVC are a mean to respect guidelines for physicians and nurses and to secure the patient's care.

Endocarditis and spondylodiscitis associated with tunneled cuffed hemodialysis catheters: hospitalizations with poor outcomes

INTRODUCTION

Patients undergoing chronic hemodialysis using tunneled cuffed catheters (TCCs) are at increased risk of metastatic infections, namely endocarditis and spondydodiscitis, and mortality is high in this group. The aim of this study was to determine the clinical features, causative organisms, its susceptibility and outcomes in patients hospitalized with these infections from a single center.

METHODS

All consecutive patients with TCC and endocarditis and/or spondylodiscitis treated at the authors' institution between 2005 and 2011 were selected retrospectively.

RESULTS

A total of 7 cases of endocarditis and 7 cases of spondylodiscitis were diagnosed. Concurrent infection was present in 1 patient. The mean age was 63.4 years, 53.8% were male, 23% had diabetes and 31% had previous immunosuppression. The average time on hemodialysis was 24 months. Those patients with endocarditis presented with fever, and 43% had previous valvular disease; mitral valve involvement was the most common. Early surgery was performed in 2 patients.Concerning spondylodiscitis, the median time from first symptom to diagnosis was 48 days. The first manifestation was back pain in 86% percent of patients, and 71% had an epidural or paraspinous abscess demonstrated by neuroimaging. One patient underwent surgical drainage of the abscess. Regarding both infections, staphylococcus aureus was the most common causative agent with a lower rate of negative blood cultures. All patients received intravenous antibiotics for a mean duration of six weeks. The mortality rate was 46%.

CONCLUSIONS

A high index of suspicion is critical in the early recognition and management of both of these infections.

Tunneled Central Venous Catheter Exchange: Techniques to Improve Prevention of Air Embolism

Malfunctioning tunneled hemodialysis central venous catheters (CVCs), because of thrombotic or infectious complications, are frequently exchanged. During the CVC exchanging procedure, there are several possible technical complications, as in first insertion, including air embolism. Prevention remains the key to the management of air embolism. Herein, we emphasize the technical tricks capable of reducing the risk of air embolism in long-term CVC exchange. In particular, adoption of a 5 to 10 degrees Trendelenburg position, direct puncture of the previous CVC venous lumen for guide-wire insertion, as opposed to guide-wire introduction after cutting the CVC, a light manual compression of the internal jugular vein venotomy site after catheter removal. The Valsalva maneuvre in collaborating patients, valved introducers, and correction of hypovolemia are also useful precautions. Principles of air embolism diagnosis and treatment are also outlined in the article.