Temporary hemodialysis catheters: recent advances

Vascular Access Type and Survival Outcomes in Hemodialysis Patients: A Seven-Year Cohort Study

Background and Objectives: Arteriovenous fistulas (AVFs) are the preferred vascular access for hemodialysis due to their impact on patient outcomes, including survival, infection rates, and overall quality of life. Despite strong recommendations favoring AVF, gaps in AVF utilization remain, influenced by clinical, demographic, and systemic factors. This study is the first to analyze survival outcomes associated with different dialysis vascular access types, adjusting for key clinical, demographic variables, and other comorbidities over extended periods. Materials and Methods: This ambispective cohort study followed 428 hemodialysis patients over seven years. Patients were categorized based on their access type: AVF (n = 189), tunneled central venous catheter (CVC) (n = 178), and non-tunneled CVC (n = 61). Kaplan-Meier survival analysis was used to estimate survival curves, and Cox proportional hazards regression adjusted for potential confounders, including age, diabetes, and hypertension. Results: The 2-year survival rates were as follows: AVF 94.1%, tunneled CVC 70.0%, and non-tunneled CVC 36.6%. The 7-year survival rates were as follows: AVF 65.5%, tunneled CVC 26.4%, and non-tunneled CVC 11.0%. Compared to AVF, tunneled CVC use was associated with a 2.8-fold increased risk of mortality (adjusted hazard ratio [AdHR] 2.8, 95% CI 2.0-4.1), while non-tunneled CVC increased the risk 5-fold (AdHR 5.0, 95% CI 3.3-7.6). Notably, older adults, women, and diabetic patients were disproportionately represented in the groups with tunneled and non-tunneled catheters. Conclusions: Adjusted survival analyses highlight the significantly lower survival rates associated with CVC use compared to AVF. Non-tunneled catheters are generally not used for prolonged periods, and this cohort provides evidence of their prognosis for long-term use. These findings reinforce the need to prioritize AVF placement whenever feasible, reinforcing health education on this topic, to improve long-term outcomes for hemodialysis patients.

Prospective Analysis of Arteriovenous Fistula Performance in the Context of Competing Risks

Key Points

Among 257 newly created arteriovenous fistulas, primary nonfunction occurred in 49%, and only 55% were ultimately used for dialysis. Loss of arteriovenous fistula patency was lower when competing risks were accounted for compared with conventional Kaplan–Meier analysis. We present icon-array plots that summarize our data and may be used a decision aid for patients in the future.

Background

Many patients with newly created arteriovenous fistulas (AVFs) may die before the AVF is needed for hemodialysis. However, formal competing risks (CRs) frameworks are rarely used to report AVF patency, which may lead to biased estimates. We sought to identify the proportion of newly created AVF experiencing primary nonfunction and describe long-term patency using a CR framework.

Methods

We conducted a prospective observational study in 257 adults with newly created AVF in Alberta, Canada. The primary outcome was primary nonfunction. Secondary outcomes included loss of primary patency, loss of assisted primary patency, and loss of secondary functional patency. Results were presented using icon-array plots to form the basis for future decision aids.

Results

Participants were 63.0% male, with mean age 62.3 years and median follow-up 18.5 months (range, 0.02–180 months). Of 257 participants, 50 could not be assessed for function or primary nonfunction, usually because of death. Of the remaining 207, 102 (49.3%) had primary nonfunction, and function was ultimately established for 142 (68.6%). Thus, only 142 of the 257 participants (55.3%) ultimately used the AVF for hemodialysis. High rates of CRs led to biased results from Kaplan–Meier analyses of lost patency. When accounting for CRs, loss of primary patency among AVFs with established function was 36.6%, 65.5%, and 66.2%, at 1, 3, and 5 years, respectively.

Conclusions

Only 55% of fistulas were ultimately used for hemodialysis when accounting for CRs and primary nonfunction. These results and the icon-array plots may inform discussions surrounding vascular access options for patients.

Identifying diversity of patient anatomy through automated image analysis of clinical ultrasounds

PURPOSE

Central venous catheterization (CVC) carries inherent risks which can be mitigated through the use of appropriate ultrasound-guidance during needle insertion. This study aims to comprehensively understand patient anatomy as it is visualized during CVC by employing a semi-automated image analysis method to track the internal jugular vein and carotid artery throughout recorded ultrasound videos.

METHODS

The ultrasound visualization of 50 CVC procedures were recorded at Penn State Health Milton S. Hershey Medical Center. The developed algorithm was used to detect the vessel edges, calculating metrics such as area, position, and eccentricity.

RESULTS

Results show typical anatomical variations of the vein and artery, with the artery being more circular and posterior to the vein in most cases. Notably, two cases revealed atypical artery positions, emphasizing the algorithm's precision in detecting anomalies. Additionally, dynamic vessel properties were analyzed, with the vein compressing on average to 13.4% of its original size and the artery expanding by 13.2%.

CONCLUSION

This study provides valuable insights which can be used to increase the accuracy of training simulations, thus enhancing medical education and procedural expertise. Furthermore, the novel approach of employing automated data analysis techniques to clinical recordings showcases the potential for continual assessment of patient anatomy, which could be useful in future advancements.

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.

Global variations in funding and use of hemodialysis accesses: an international report using the ISN Global Kidney Health Atlas

BACKGROUND

There is a lack of contemporary data describing global variations in vascular access for hemodialysis (HD). We used the third iteration of the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA) to highlight differences in funding and availability of hemodialysis accesses used for initiating HD across world regions.

METHODS

Survey questions were directed at understanding the funding modules for obtaining vascular access and types of accesses used to initiate dialysis. An electronic survey was sent to national and regional key stakeholders affiliated with the ISN between June and September 2022. Countries that participated in the survey were categorized based on World Bank Income Classification (low-, lower-middle, upper-middle, and high-income) and by their regional affiliation with the ISN.

RESULTS

Data on types of vascular access were available from 160 countries. Respondents from 35 countries (22% of surveyed countries) reported that > 50% of patients started HD with an arteriovenous fistula or graft (AVF or AVG). These rates were higher in Western Europe (n = 14; 64%), North & East Asia (n = 4; 67%), and among high-income countries (n = 24; 38%). The rates of > 50% of patients starting HD with a tunneled dialysis catheter were highest in North America & Caribbean region (n = 7; 58%) and lowest in South Asia and Newly Independent States and Russia (n = 0 in both regions). Respondents from 50% (n = 9) of low-income countries reported that > 75% of patients started HD using a temporary catheter, with the highest rates in Africa (n = 30; 75%) and Latin America (n = 14; 67%). Funding for the creation of vascular access was often through public funding and free at the point of delivery in high-income countries (n = 42; 67% for AVF/AVG, n = 44; 70% for central venous catheters). In low-income countries, private and out of pocket funding was reported as being more common (n = 8; 40% for AVF/AVG, n = 5; 25% for central venous catheters).

CONCLUSIONS

High income countries exhibit variation in the use of AVF/AVG and tunneled catheters. In low-income countries, there is a higher use of temporary dialysis catheters and private funding models for access creation.

Management of Intermittent Hemodialysis in the Critically Ill Patient

Intermittent hemodialysis remains a cornerstone of extracorporeal KRT in the intensive care unit, either as a first-line therapy for AKI or a second-line therapy when patients transition from a continuous or prolonged intermittent therapy. Intermittent hemodialysis is usually provided 3 days per week in this setting on the basis that no clinical benefits have been demonstrated with more frequent hemodialysis. This should not detract from the importance of continually assessing and refining the hemodialysis prescription (including the need for extra treatments) according to dynamic changes in extracellular volume and other parameters, and ensuring that an adequate dose of hemodialysis is being delivered to the patient. Compared with other KRT modalities, the cardinal challenge encountered during intermittent hemodialysis is hemodynamic instability. This phenomenon occurs when reductions in intravascular volume, as a consequence of ultrafiltration and/or osmotic shifts, outpace compensatory plasma refilling from the extravascular space. Myocardial stunning, triggered by intermittent hemodialysis, and independent of ultrafiltration, may also contribute. The hemodynamic effect of intermittent hemodialysis is likely magnified in patients who are critically ill due to an inability to mount sufficient compensatory physiologic responses in the context of multiorgan dysfunction. Of the many interventions that have undergone testing to mitigate hemodynamic instability related to KRT, the best evidence exists for cooling the dialysate and raising the dialysate sodium concentration. Unfortunately, the evidence supporting routine use of these and other interventions is weak owing to poor study quality and limited sample sizes. Intermittent hemodialysis will continue to be an important and commonly used KRT modality for AKI in patients with critical illness, especially in jurisdictions where resources are limited. There is an urgent need to harmonize the definition of hemodynamic instability related to KRT in clinical trials and robustly test strategies to combat it in this vulnerable patient population.

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.

Accessory veins related hand ischemia: A case series

INTRODUCTION

Arteriovenous fistula is considered as a lifeline for chronic kidney patients undergoing maintenance hemodialysis.

OBJECTIVE

To study the outcome of ligation of the accessory vein causing hyperperfusion and ischemia of the ipsilateral limb.

METHOD

ology: A single institution, single surgeon, in-hospital, retrospective case series of patients presented with alarm symptoms in postoperative period following arteriovenous fistula.

RESULTS

A total of 800 AVF were created between 2016 and 2019, out of which 6/800 (0.75 %) patients presented with alarm symptoms related to venous hypertension and underwent accessory vein ligation. All showed normal recovery with complete resolution of symptoms postoperatively.

CONCLUSION

Timely ligation of the accessory vein in patients with arteriovenous fistula with accessory vein related alarm symptoms showed salvage of lifeline and limb with no residual complications during follow-up.

Ultrasound in central venous access for hemodialysis

Central venous cannulation is a frequent need for urgent or scheduled hemodialysis. Many studies confirmed the pivotal role of ultrasound in this procedure. Vascular access guidelines strongly recommend ultrasound guidance. Its usefulness has been demonstrated not only in reducing complications of venipuncture but more recently for the evaluation of central venous catheter (CVC) placement and real-time check for possible complications. The use of ultrasound requires a precise technique for the correct handling of the probe and the needle movement. Different approaches as the out-of-plane, in-plane, and oblique methods are available, enabling the most appropriate for the individual case. Although the learning curve for CVC ultrasound placement is usually fast, formal training and certification for beginners are strongly recommended.

Association of diabetes, education level, and care dependency with use of temporary vascular access in patients with chronic kidney disease

OBJECTIVE

Temporary vascular access (TVA) is frequently used during the first dialysis in patients with chronic kidney disease (CKD), and it is associated with an increased risk of infection, central vein stenosis, and mortality. Here, factors associated with TVA in patients with CKD were explored.

METHODS

This study included patients in a single-center CKD care program who initiated long-term renal replacement therapy. The primary outcome was TVA use at first dialysis. Factors possibly associated with TVA use were analyzed using Cox regression.

RESULTS

Temporary vascular access was used in 53.2% of the patients at first dialysis. In total, 73.2% (n = 865) and 26.8% (n = 317) of the patients were on hemodialysis and peritoneal dialysis, respectively. Multivariate Cox regression analysis showed that TVA use in patients with CKD was associated with diabetes (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.28-1.81, p < 0.001), lower albumin (HR 0.82, 95% CI 0.75-0.91, p < 0.001), lower education level (HR 0.75, 95% CI 0.56-1.00, p = 0.055), and total care dependency (HR 1.92, CI 1.44-3.43, p = 0.003).

CONCLUSION

Diabetes, education level, and care dependency are associated with TVA at dialysis initiation in patients with CKD.

Surface modification strategies for hemodialysis catheters to prevent catheter-related infections: A review

Insertion of a central venous catheter is one of the most common invasive procedures applied in hemodialysis therapy for end-stage renal disease. The most important complication of a central venous catheter is catheter-related infections that increase hospitalization and duration of intensive care unit stay, cost of treatment, mortality, and morbidity rates. Pathogenic microorganisms, such as, bacteria and fungi, enter the body from the catheter insertion site and the surface of the catheter can become colonized. The exopolysaccharide-based biofilms from bacterial colonies on the surface are the main challenge in the treatment of infections. Catheter lock solutions and systemic antibiotic treatment, which are commonly used in the treatment of hemodialysis catheter-related infections, are insufficient to prevent and terminate the infections and eventually the catheter needs to be replaced. The inadequacy of these approaches in termination and prevention of infection revealed the necessity of coating of hemodialysis catheters with bactericidal and/or antiadhesive agents. Silver compounds and nanoparticles, anticoagulants (e.g., heparin), antibiotics (e.g., gentamicin and chlorhexidine) are some of the agents used for this purpose. The effectiveness of few commercial hemodialysis catheters that were coated with antibacterial agents has been tested in clinical trials against catheter-related infections of pathogenic bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis with promising results. Novel biomedical materials and engineering techniques, such as, surface micro/nano patterning and the conjugation of antimicrobial peptides, enzymes, metallic cations, and hydrophilic polymers (e.g., poly [ethylene glycol]) on the surface, has been suggested recently.

Challenges of Vascular Access in the Pediatric Population

The incidence and prevalence of renal replacement therapy has continued to increase in the pediatric population. Recent data have shown that hemodialysis was the most frequently used dialysis modality, especially in pediatric ESRD patients (age 0-21 years). A well-functioning vascular access is required for effective hemodialysis and choosing the best vascular access option for pediatric patients can be difficult. Pediatric vascular options include arteriovenous fistula, arteriovenous graft, and central venous catheters (CVCs). There is a national initiative for fistula first-catheter last approach; however, CVCs have been reported as the most conventionally utilized vascular access option in pediatric patients. The use of CVCs should be minimized or avoided as they are associated with high risk of infections, thrombosis, and other complications. Thus, it is important for practitioners to plan appropriately in advance, practice good clinical judgment, and assure that the best vascular access is placed according to the patient's needs. Therefore, this article reviews the different types of pediatric vascular access and the associated benefits and potential complications of each.

Multilevel analysis of hemodialysis-associated infection among end-stage renal disease patients: results of a retrospective cohort study utilizing the insurance claim data of Fukuoka Prefecture, Japan

The presence of comorbid conditions along with heterogeneity in terms of healthcare practices and service delivery could have a significant impact on the patient's outcomes. With a strong interest in social epidemiology to examine the impact of health services and variations on health outcomes, the current study was conducted to analyse the incidence of hemodialysis-associated infection (HAI) as well as its associated factors, and to quantify the extent to which the contextual effects of the care facility and regional variations influence the risk of HAI.A total of 6111 patients with end-stage renal disease who received hemodialysis treatment between 1 October 2015 and 31 March 2016 were identified from the insurance claim database as a population-based, close-cohort retrospective study. Patients were followed for one year from April 1, 2016 to March 31, 2017. A total of 200 HAI cases were observed during the follow-up and 12 patients died within 90 days of the onset of HAI. Increased risks for HAI were associated with moderate (HR 1.73, 95% confidence interval [CI] 1.00-2.98) and severe (HR 1.87, 95% CI 1.11-3.14) comorbid conditions as well as malignancy (HR 1.36, 95% CI 1.00-1.85). Increased risk was also seen among patients who received hemodialysis treatment from clinics (HR 2.49, 95% CI 1.1-5.33). However, these statistics were no longer significant when variations at the level of care facilities were statistically controlled. In univariate analyses, no statistically significant association was observed between 90-day mortality and baseline patients, and the characteristics of the care facility.The results of the multivariate, multilevel analyses indicated that HAI variations were only significant at the care facility level (σ 2.07, 95% CI 1.3-3.2) and were largely explained by the heterogeneity between care facilities. The results of this study highlight the need to look beyond the influence of patient-level characteristics when developing policies that aim at improving the quality of hemodialysis healthcare and service delivery in Japan.

Análise das taxas de infecção e duração de cateteres de hemodiálise de curta e longa permanência em hospital de ensino

Resumo Contexto Os cateteres venosos centrais para hemodiálise (CVCH) de curta permanência (CCP) e cateteres tunelizáveis de longa permanência (CTLP) são fundamentais para a terapia hemodialítica. Entretanto, há escassa casuística nacional acerca da incidência de complicações desses dois tipos de cateteres. Objetivos Analisar as complicações e tempo de duração de CVCHs em centro de hemodiálise de hospital de ensino. Métodos Foi feito um estudo unicêntrico, longitudinal e retrospectivo de 115 pacientes consecutivos submetidos a implante de cateteres para hemodiálise (67 CCP e 48 CTLP) em um período de 2 anos, com análise de sobrevida geral, perviedade, perda do acesso e incidência de complicações. Resultados Sessenta por cento eram do sexo masculino e a média de idade foi de 62 anos. O principal sítio de punção foi a veia jugular interna direita. Hipertensão arterial sistêmica estava presente em 95% dos casos. A mediana de permanência do cateter foi de 50 dias (CCP) versus 112 dias (CTLP; p < 0,0001). Não houve diferença na sobrevida global. Infecção relacionada ao cateter apresentou maior incidência nos CCP, sendo Staphylococcus sp. o microrganismo mais encontrado. A taxa de infecção por 1.000 dias foi maior nos CCP em relação aos CTLP (16,7 eventos/1.000 dias versus 7,0 eventos/1.000 dias, respectivamente). Baixa renda foi o único fator relacionado a maior incidência de infecção. Conclusões O tempo de permanência dos CTLP foi significativamente maior que os CCP, porém ainda assim abaixo dos valores relatados na literatura e sem impacto na sobrevida global. Baixa renda foi um fator associado a infecção de cateter.

Clinical Survey of Decreased Blood Flow Rate in Continuous Renal Replacement Therapy: A Retrospective Observational Study

Background

Continuous renal replacement therapy (CRRT) is an essential procedure for patients with acute kidney injury in intensive care. It is important to maintain an adequate blood flow rate during CRRT. Several previous studies have reported the relationships between blood flow rate and filter lifespan, or circuit life, in CRRT. Here, we aim at elucidating the incidence and factors associated with a decreased blood flow rate in CRRT.

Methods

This is a retrospective observational study. From January 2014 to June 2017, 119 patients who underwent CRRT in the intensive care unit were enrolled. The definition of a decreased blood flow rate included situations in which the medical staff needed to decrease the blood flow volume. We statistically analyzed the association of the decreased blood flow rate with patients' clinical characteristics.

Results

Of 119 patients, 52 required a decreased blood flow rate during CRRT. Almost half of the cases occurred within one day of starting CRRT. None of the clinical factors (age, sex, height, sequential organ failure assessment (SOFA) score, catheter position, systemic infection, albumin, hemoglobin, and activating coagulation time) were significantly associated with decreased blood flow rate.

Conclusions

A decreased blood flow rate often occurs during CRRT. Clinical factors significantly associated with the occurrence of the decreased blood flow rate were not detected in the current study. Further investigation regarding the occurrence of a decreased blood flow is warranted.

Short-term dialysis catheter versus central venous catheter infections in ICU patients: a post hoc analysis of individual data of 4 multi-centric randomized trials

PURPOSE

Little is known on catheter-related infections associated with short-term dialysis catheters (DC). Recommendations for infection prevention are mostly derived from those related to central venous catheters (CVC). A comparison of infectious risk of DCs and CVCs would be instrumental for improving infection control prevention strategies. This study aimed to describe differences in infectious risk between DC and CVC.

METHODS

We used individual data from 4 multicenter randomized controlled trials in intensive care units (ICUs) that evaluated various prevention strategies regarding colonization, major catheter-related infections (MCRI) and catheter-related bloodstream infections (CR-BSI). We selected only catheters with non-chlorhexidine gluconate impregnated dressings. A marginal Cox model for clustered data was used for the evaluation of the daily hazard rate for catheter-tip colonization, MCRI and CR-BSI.

RESULTS

We included 3029 patients and 4148 catheters (31,547 catheter-days) which comprised 1872 DCs and 2276 CVCs. After adjustment on confounders, we identified an increased risk in DC compared to CVC for colonization (HR 1.45, 95% CI 1.03-2.04, p = 0.04) and for MCRI (HR 2.97, 95% CI 1.03-8.51, p = 0.04) in the first 7 days of catheter maintenance. The daily hazard rate for colonization and MCRI was generally higher for DC in the first catheter-days, whereas it was similar between DC and CVC for longer catheterizations.

CONCLUSIONS

The daily risk of colonization and MCRI was significantly higher in DC compared to CVC within the first 7 days of catheter maintenance. Targeted prevention strategies for DC should mostly focus on the period following the insertion.

A Survey of Training for Temporary Hemodialysis Catheter Insertion During Nephrology Fellowship in Canada: An Update

Background

Controversy exists as to whether the insertion of temporary hemodialysis catheters (THDCs) should remain a mandatory requirement of nephrology fellowship training in Canada. A survey conducted by our group in 2012 showed that many nephrology trainees reported inadequate training to achieve procedural competence.

Objective

To determine the current practices and training of the insertion of THDCs in nephrology fellowship programs in Canada and how this has evolved since 2012.

Design

A survey study was designed comprising the following sections: demographics, details regarding the number and types of THDCs inserted within the past 6 months of fellowship training, adherence to sterile techniques, the use of ultrasound guidance during THDC insertion, training for THDC insertion received before and during nephrology fellowship, and self-perceived adequacy of training and competence in THDC insertion.

Setting

The survey was distributed by e-mail in May 2018 either directly or through Canadian nephrology training programs.

Participants

Current trainees of Canadian adult nephrology training programs.

Measurements

Descriptive statistics were used to analyze the summarized data. The means and interquartile ranges (IQRs) were used to summarize the number of THDC insertions performed, and the categorical data, including data on training and self-perceived competency, were reported using frequencies and percentages. A chi-squared test was used to evaluate the relationship between those who received simulation-based training and self-perceived confidence in either internal jugular or femoral catheter insertion.

Methods

An online survey, available in both English and French, was distributed to all adult nephrology trainees in Canada in May 2018 either directly or through their respective programs.

Results

Completed surveys were received from 46 of 136 nephrology trainees across Canada (34%). Of those who responded, the median (IQR) number of combined femoral and/or internal jugular THDCs inserted in the past 6 months of fellowship training was 3 (1-6). Eight respondents (17%) indicated that they had not inserted a THDC in the past 6 months. However, only 7 of 42 respondents (17%) indicated that they did not feel competent or adequately trained to perform either femoral or internal jugular THDC insertion.

Limitations

Limitations of the study include participation of trainees at different stages of their training. Many trainees indicated that it was not a requirement to keep a formal log of their procedures performed and likely had recall bias when reporting their procedure details.

Conclusions

Nephrology fellows in Canada are performing fewer THDC insertions compared to 2012 but report higher levels of self-perceived competence and better training. This may be as a result of significantly more simulation-based training. Our data suggest that training to procedural mastery using simulation-based techniques may be a path to ensuring adequate training for THDC insertion despite fewer procedures being performed during training.

Dialysis catheters in the ICU: selection, insertion and maintenance

PURPOSE OF REVIEW

Choosing the best catheter for renal replacement therapy (RRT) is not an easy task. Beyond catheter length, many of its properties can influence effectiveness of the RRT session. Maintenance between sessions, particularly the locking solution, also impacts catheter lifespan and infection rates.

RECENT FINDINGS

Many innovations in dialysis catheters have been proposed by the industry over the past decade, including the material used, the shape of the lumens and the position of the inflow and outflow holes. Impregnated catheters have also been developed to prevent catheter-related infections. Many locking solutions are available, either for maintaining catheter patency or for preventing infections.

SUMMARY

Although studies conducted in the specific context of the ICU are still scarce, some conclusions can be drawn. Catheter length must be adapted to the insertion site to reach an area of high blood flow. Kidney-shape lumens appear to be less thrombogenic and seem to prevent catheter dysfunction. Catheter tip and lumen holes also affect catheter function. For catheter locking, 4% citrate appears nowadays as one of the best options, but taurolidine-based solutions are also interesting.

Common errors in temporary hemodialysis catheter insertion

Non-tunneled hemodialysis catheter (NTHC) insertion is an essential skill for nephrology practice and remains a requirement of training. However, improper insertion technique can increase the risk of potentially fatal infectious and mechanical complications. Evidence-based strategies can reduce the rates of such complications and should be integrated into practice and training. Ultrasound (US) guidance should routinely be used for NTHC insertion at the femoral and internal jugular sites (with avoidance of the subclavian site). Nephrologists should receive proper training in the use of US for line insertion. With respect to other aspects of the procedure, proper insertion technique readily prevents guidewire-induced arrhythmias. In addition, adherence to infection-control guidelines results in a sustainable reduction in bloodstream infections. All these aspects of NTHC insertion may be best taught and evaluated through a program that includes simulation-based mastery learning (SBML) training. As a separate issue, nephrologists (and intensivists) should be aware that a dysfunctional catheter should be replaced at a new site rather than being changed over a guidewire. This review of common errors related to NTHC insertion seeks to highlight evidence-based approaches to practice and training.

Routine use of ultrasound to avert mechanical complications during placement of tunneled dialysis catheters for hemodialysis

OBJECTIVE

While placement of tunneled dialysis catheters for hemodialysis access is considered a routine procedure, it is associated with a small chance of mechanical complications. Because the literature examining these issues is not recent and our impression of the incidence of these postprocedural complications is at variance with the existing literature, we decided to review our experience.

METHODS

Since 1998, our vascular service has placed 1766 tunneled hemodialysis catheters in 1065 patients for hemodialysis access. All catheters were placed with ultrasound guidance for the puncture, with selective use of a micropuncture set for patients with low-volume status. All patients underwent chest radiography at the end of each procedure.

RESULTS

The average age of the patients was 61 ± 21 (standard deviation) years. Among the 1065 patients, 44% were female; 93% of catheters were placed in the right internal jugular vein and 7% in the left internal jugular vein. The prevalence of diabetes and hypertension in our population of patients was 52% and 72%, respectively. In this consecutive series, no case of postprocedure hemothorax or pneumothorax was encountered. Two cutdowns had to be performed because of injury to branches of the external carotid artery. Three patients had to have a subsequent revision because of malpositioning of the catheter.

CONCLUSIONS

Using modern-day techniques, the incidence of mechanical complications during placement of tunneled catheters can be diminished. Hence, routine use of ultrasound guidance for insertion of tunneled dialysis catheters should become the standard of care.

Survey of non-tunneled temporary hemodialysis catheter clinical practice and training

BACKGROUND

Nephrologists are placing fewer non-tunneled temporary hemodialysis catheters. Requiring competence for nephrology fellow graduation is controversial.

METHODS

Anonymous, online survey of all graduates from a single, military nephrology training program (n = 81; 1985-2017) and all US Nephrology program directors (n = 150).

RESULTS

Graduate response and completion rates were 59% and 100%, respectively; 93% agreed they had been adequately trained; 58% (26/45) place non-tunneled temporary hemodialysis catheters, independent of academic practice or time in practice, but 12/26 did ⩽5/year and 23/26 referred some or all. The most common reason for continuing non-tunneled temporary hemodialysis catheter placement was that it is an essential emergency procedure (92%). The single most significant barrier was time to do the procedure (49%). Program director response and completion rates were 50% and 79%, respectively. The single most important barrier to fellow competence was busyness of the service (36%), followed by disinterest (21%); 55% believed that non-tunneled temporary hemodialysis catheter insertion competence should be required, with 81% indicating it was an essential emergency procedure. The majority of graduates and program directors agreed that simulation training was valuable; 76% of programs employ simulation. Graduates who had simulation training and program directors with ⩽20 years of practice were significantly more likely to agree that simulation training was necessary.

CONCLUSION

Of the graduate respondents from a single training program, 58% continue to place non-tunneled temporary hemodialysis catheters; 55% of program directors believe non-tunneled temporary hemodialysis catheter procedural competence should be required. Graduates who had non-tunneled temporary hemodialysis catheter simulation training and younger program directors consider simulation training necessary. These findings should be considered in the discussion of non-tunneled temporary hemodialysis catheter curriculum requirements.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Dialysis Catheter Placement via the Left Internal Jugular Vein: Risk of Brachiocephalic Vein Perforation

Purpose

We discuss a case of a brachiocephalic vein (BCV) perforation after Tesio® central venous catheter insertion.

Method and Results

An 80-year-old patient underwent an ultrasound-guided hemodialysis (HD) catheter placement via his left internal jugular vein (IJV). One day postoperatively, the patient became hemodynamically unstable immediately after HD initiation. As a vascular event was feared, an emergency CT scan was performed demonstrating a BCV perforation. The patient underwent a sternotomy, the lines were removed and the venous laceration was closed. The patient recovered well.

Conclusions

In spite of ultrasound guidance, fluoroscopy for guidewire and sheath advancement, venous blood aspiration and a normal appearing postoperative x-ray, traumatic central venous catheter placement is still possible. Tenting of the BCV wall during catheter advancement possibly caused the venous perforation. A ‘how-to’ for correct catheter placement via the IJV is provided and potential pitfalls during each procedural step are discussed.

Achieving Procedural Competence during Nephrology Fellowship Training: Current Requirements and Educational Research

Concerns have previously been raised as to whether training programs are ensuring that nephrology fellows achieve competence in the procedural skills required for independent practice. We sought to review the current requirements for procedural training as well as educational research pertaining to achieving competence in the core nephrology procedures of nontunneled (temporary) hemodialysis catheter insertion and percutaneous kidney biopsy. At this time, there is no universal approach to procedural training and assessment during nephrology fellowship. Nonetheless, simulation-based mastery learning programs have been shown to be effective in improving fellows' skills in nontunneled (temporary) hemodialysis catheter insertion and should be provided by all nephrology training programs. For percutaneous kidney biopsy, the development and evaluation of inexpensive simulators are a promising starting point for future study. Current practice with respect to procedural training during nephrology fellowship remains imperfect; however, the ongoing shift toward competency-based evaluation provides opportunities to refocus on improvement.

Haemodialysis catheters in the intensive care unit

Ten to 15% of critically ill patients need renal replacement therapy (RRT) for severe acute kidney injury. The dialysis catheter is critical for RRT quality and efficiency. Catheters have several properties that must be optimized to promote RRT success. The distal tip has to be located in a high blood flow location, which means central venous territory. Therefore, catheters are mostly inserted into the right internal jugular vein or in femoral veins. External diameter should vary from 12 to 16 Fr in order to ensure adequate blood flow inside the catheter. Lumen shapes are theoretically designed to limit thrombotic risk with low turbulences and frictional forces against the internal wall. With low aspiration pressure, distal tip shape has to deliver sufficient blood flow, while limiting recirculation rate. Catheter material should be biocompatible. Despite in vitro data, no strong evidence supports the use of coated catheters in the ICU in order to reduce infectious risk. Antibiotic "lock" solutions are not routinely recommended. Ultrasound guidance for catheterization significantly decreases mechanical complications. Clinicians should select the optimal catheter according to patient body habitus, catheter intrinsic properties and RRT modality to be used.

Practical Aspects of Nontunneled and Tunneled Hemodialysis Catheters

Nontunneled hemodialysis catheters (NTHCs) are typically used when vascular access is required for urgent renal replacement therapy. The preferred site for NTHC insertion in acute kidney injury is the right internal jugular vein followed by the femoral vein. When aided by real-time ultrasound, mechanical complications related to NTHC insertion are significantly reduced. The preferred site for tunneled hemodialysis catheters placement is the right internal jugular vein followed by the left internal jugular vein. Ideally, the catheter should be inserted on the opposite side of a maturing or planned fistula/graft. Several dual-lumen, large-diameter catheters are available with multiple catheter tip designs, but no one catheter has shown significant superior performance.

Clinical Outcomes of Cryopreserved Arterial Allograft Used as a Vascular Conduit for Hemodialysis

This single center cohort study aimed to test the hypothesis that use of a cryopreserved arterial allograft could avoid the maturation or healing process of a new vascular access and to evaluate the patency of this technique compared with that of vascular access using a prosthetic graft. Between April 2012 and March 2013, 20 patients underwent an upper arm vascular access using a cryopreserved arterial allograft for failed or failing vascular accesses and 53 using a prosthetic graft were included in this study. The mean duration of catheter dependence, calculated as the time interval from upper arm access placement to removal of the tunneled central catheter after successful cannulation of the access, was significantly longer for accesses using a prosthetic graft than a cryopreserved arterial allograft (34.4 ± 11.39 days vs. 4.9 ± 8.5 days, P < 0.001). In the allograft group, use of vascular access started within 7 days in 16 patients (80%), as soon as from the day of surgery in 10 patients. Primary (unassisted; P = 0.314) and cumulative (assisted; P = 0.673) access survivals were similar in the two groups. There were no postoperative complications related to the use of a cryopreserved iliac arterial allograft except for one patient who experienced wound hematoma. In conclusion, upper arm vascular access using a cryopreserved arterial allograft may permit immediate hemodialysis without the maturation or healing process, resulting in access survival comparable to that of an access using a prosthetic graft.

Performance of Temporary Hemodialysis Catheter Insertion by Nephrology Fellows and Attending Nephrologists

BACKGROUND AND OBJECTIVES

Concerns have been raised about nephrology fellows' skills in inserting temporary hemodialysis catheters. Less is known about temporary hemodialysis catheter insertion skills of attending nephrologists supervising these procedures. The aim of this study was to compare baseline temporary hemodialysis catheter insertion skills of attending nephrologists with the skills of nephrology fellows before and after a simulation-based mastery learning (SBML) intervention.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This pre- post-intervention study with a pretest-only comparison group was conducted at the University of Toronto in September of 2014. Participants were nephrology fellows and attending nephrologists from three university-affiliated academic hospitals who underwent baseline assessment of internal jugular temporary hemodialysis catheter insertion skills using a central venous catheter simulator. Fellows subsequently completed an SBML intervention, including deliberate practice with the central venous catheter simulator. Fellows were expected to meet or exceed a minimum passing score at post-test. Fellows who did not meet the minimum passing score completed additional deliberate practice. Attending nephrologist and fellow baseline performance on the temporary hemodialysis catheter skills assessment was compared. Fellows' pre- and post-test temporary hemodialysis catheter insertion performance was compared to assess the effectiveness of SBML. The skills assessment was scored using a previously published 28-item checklist. The minimum passing score was set at 79% of checklist items correct.

RESULTS

In total, 19 attending nephrologists and 20 nephrology fellows participated in the study. Mean attending nephrologist checklist scores (46.1%; SD=29.5%) were similar to baseline scores of fellows (41.1% items correct; SD=21.4%; P=0.55). Only two of 19 attending nephrologists (11%) met the minimum passing score at baseline. After SBML, fellows' mean post-test score improved to 91.3% (SD=6.9%; P<0.001). Median time between pre- and post-test was 24 hours.

CONCLUSIONS

Attending nephrologists' baseline temporary hemodialysis catheter insertion skills were highly variable and similar to nephrology fellows' skills, with only a small minority able to competently insert a temporary hemodialysis catheter. SBML was extremely effective for training fellows and should be considered for attending nephrologists who supervise temporary hemodialysis catheter insertions.

Should nephrologists take a larger role in interventional nephrology, and should central line insertion remain a requirement of nephrology residency training? A debate

The Canadian Society of Nephrology must soon provide input concerning the future of procedural training in nephrology. While at one time, the ability to insert a central venous catheter (CVC) was an essential skill required by all nephrologists, in 2014, nephrology training and practice has changed in fundamental ways such that it would be both unreasonable, and impractical, to maintain this requirement. Indeed, survey evidence suggests that many current trainees are not achieving this competency. Amongst the reasons that this requirement should be withdrawn include: 1) Not all trainees have the procedural skills to safely learn to insert CVC's. 2) Most nephrologists in training and in practice are intellectually oriented, not procedurally oriented and are not seeking to perform lots of procedures. 3) In most practice settings, interventional radiologists and intensive care doctors perform dialysis line insertions using real time ultrasound guidance frequently, and offer timely, safer, and better service to patients. 4) Most trainees will not enter practice settings where CVC insertion ability is required. 5) Otherwise excellent future trainees may be denied a nephrology certificate of special competence only because they are unable to insert a CVC by the end of their fellowship. 6) Academic nephrology training programs that cannot provide adequate CVC insertion experience to fellows may lose their status as training centres. As a pragmatic way forward, Canadian nephrology training programs must encourage and offer only those nephrology trainees who have the ability and interest in procedural nephrology, a pathway through which they may be provided superb advanced training to become an expert. There is no longer a compelling reason to mandate this for all trainees.

Efficacy and Safety of a New Technique of Conversion from Temporary to Tunneled Central Venous Catheters

The usually applied conversion technique from temporary to tunneled central venous catheters (CVCs) using the same venous insertion site requires a peel-away sheath. We propose a conversion technique without peel-away sheath: a guide wire is advanced through the existing temporary CVC; then, a subcutaneous tunnel is created from the exit to the venotomy site. After removing the temporary CVC, the tunneled one is advanced along the guide wire. The study group included all patients requiring a catheter conversion from January 2012 to June 2014; the control group included incident patients who had received de novo placement of tunneled CVCs from January 2010 to December 2011. The main outcome measures were technical success and immediate complications. Seventy-two tunneled catheters (40 with our conversion technique and 32 with the traditional one) were placed in 72 patients. The technical success was 95% in the study group and 75% in the controls (p = 0.019). The immediate complications were one bleeding in the study group (2.5%) and one air embolism, one pneumothorax, and four bleedings (18.7%) in the controls (p = 0.039). Conversion from temporary to tunneled CVC using a guide wire and without a peel-away sheath is an effective and safe procedure.