Why Does Vascular Access Dysfunction Occur despite Brachial Artery Blood Flow Being Higher than Preset Blood Flow?

Background: In recent years, many reports have investigated the usefulness of brachial artery blood flow (BAF) measured by ultrasonography as an evaluation index for the vascular access (VA) stenosis of hemodialysis patients. However, the mechanism of VA dysfunction, despite BAF being higher than the preset blood flow, has not been clarified to date. Methods: The relationship between actual blood-removal flow and recirculation rate with decreasing VA flow was examined using a VA flow path model and pure water as a model fluid. The blood-flow rate was set at 180 mL/min, and the set VA flow rate was lowered stepwise from 350 to 50 mL/min. VA flow rate, blood-removal flow rate, and flow waveform measured between two needle-puncture sites were recorded, and then the actual blood-removal flow rate and recirculation rate were calculated. Results: Recirculation was observed at a VA flow rate < 300 mL/min. The recirculation was due to the VA flow rate, which was transiently reduced to the level below the blood-removal flow rate, resulting in backflow. In contrast, no decrease in the actual blood-removal flow rate was observed. Conclusion: It is suggested that the mechanism of the VA dysfunction, despite the BAF being higher than the preset blood-flow rate, was due to the diastolic BAF being lower than the blood-removal flow rate.

Surveillance of Hemodialysis Related Infections: A Prospective Multicenter Study

There is neither a surveillance system nor a study to reveal the HD related infection rates in Turkey. We aimed to investigate the infection rate among HD outpatients and implement CDC’s surveillance system. A multicenter prospective surveillance study is performed to investigate the infection rate among HD patients. CDC National Healthcare Safety Network dialysis event (DE) protocol is adopted for definitions and reporting. During April 2016–April 2018, 9 centers reported data. A total of 199 DEs reported in 10035 patient-months, and the overall DE rate was 1.98 per 100 patient-months. Risk of blood culture positivity is found to be 17.6 times higher when hemodialysis was through a tunneled catheter than through an arteriovenous fistula. DE rate was significantly lower in patients educated about the care of their vascular access site. Staphylococcus aureus was the most causative microorganism among mortal patients. Outcomes of DEs were hospitalization (73%), loss of vascular access (18.2%), and death (7.7%). This first surveillance study revealed the baseline status of HD related infections in Turkey and showed that NHSN DE surveillance system can be easily implemented even in a high workload dialysis unit and be adopted as a nationwide DE surveillance program.

Atypical presentation of fistula dysfunction due to brachial arterial embolization mimicking stroke

Vascular access thrombosis is an important complication with great impact on access patency and, consequently, on a patient’s quality of life and survival. We report the case of a 73-year-old woman with chronic kidney disease on hemodialysis with a radiocephalic arteriovenous fistula on the right arm that was brought to the emergency department with decreased strength in her right arm, ipsilateral hypoesthesia and facial hemi-hypoesthesia. The patient was given a brain computed tomographic scan that did not confirm suspicion of stroke. On re-examination, the patient had new-onset pain at arteriovenous fistula level, and her right arm was cold and pale. The nephrology department was called for arteriovenous fistula evaluation. On physical examination, her forearm fistula had a decreased thrill and arm elevation exacerbated its paleness. A bedside ultrasound was performed for arteriovenous fistula assessment. Doppler ultrasound revealed: partial thrombosis at brachial bifurcation, a flow of 80–105 mL/min at brachial artery level and a radial artery with a damped waveform. Anastomosis and draining vein were permeable. In this case, the diagnosis of acute embolic brachial artery occlusion was made by a fast bedside ultrasound evaluation. The patient underwent thromboembolectomy with Fogarty technique, recovering fistula thrill, radial and cubital pulses. Thromboembolism of the fistula feeding artery is a rare cause of vascular access thrombosis and it is rarely mentioned in the literature. In this report, failure to recognize the upper limb ischemia would have led to delayed treatment, potentially resulting in the fistula’s complete thrombosis and further limb ischemia. We highlight the importance of a diagnosis method like Doppler ultrasound, which allows for rapid evaluation at the patient’s bedside.

Use of chronically occluded fistula to establish access outflow

Maintaining a good quality vascular access in the long term can become particularly challenging especially in patients that are on dialysis for many years and present with exhausted venous capital and chronic access related complications. We present a 60-year-old female patient with multiple bilateral previous failed accesses, a previous distal revascularization interval ligation (DRIL) for hemodialysis access induced distal ischemia (HAIDI). Her chronically (more than a month) occluded arteriovenous fistula AVF was used to establish outflow and create a functioning forearm arteriovenous graft (AVG).

Vascular Access in Pediatric Oncology and Hematology: State of the Art

Management and successful use of vascular access are critical issues in pediatric patients affected by malignancies. Prolonged course of disease, complex and various treatment protocols require long-lasting vascular access providing adequate tools to administrate those therapies and to collect routine blood sampling without painful and repeated venipuncture. For these reasons, central venous catheters are currently an important component in pediatric onco-hematological care, with a direct influence on outcome. Indeed, there are peculiar issues (techniques of insertion, management, complications etc.) which must be well-known in order to improve the outcome and the quality of life of children with cancer.

Ultrasound Guided Vascular Access in The Neonatal Intensive Care Unit: A Nationwide Survey

Ultrasound guided percutaneous vascular access (USG-PVA) is recommended by international practice guidelines but information regarding its use in the neonatal intensive care unit (NICU) is lacking. Our objective was to assess neonatologist’s perceptions and current implementation of USG-PVA in Spain. This was a nationwide online survey. The survey was composed of 37 questions divided in 4 domains: 1) neonatologist’s background, 2) NICU characteristics, 3) personal perspectives about USG-PVA and clinical experience in USG-PVA. One hundred and eighty survey responses from 59 NICUs (62% of Spanish NICUs) were analyzed. Most neonatologist (81%) perceive that competence in USG-PVA is indispensable or very useful in clinical practice. However, 64 (35.5%) have never used USG-PVA in real patients. Among neonatologists with some experience in USG-PVA most perform less than 5 procedures per year (59% in venous access and 80% in arterial access) and a 38% and 60% have never used USG for venous and arterial access respectively in very low birth weight infants (VLBWI). Spanish neonatologists report that residents/fellows training in USG-PVA is absent (52.2%) or unstructured (32%) in their units. The lack of adequate training is identified by a 60% of neonatologists as the most important barrier for implementation of USG-PVA and 87% would recommend that future neonatologists receive formal training. In conclusion, Spanish neonatologists perceive that USG-PVA is important in clinical practice but, currently these techniques are largely underused. Our results indicate that specific training in USG-PVA should be implemented in the NICU.