Vascular access management 1: an overview

Design of composite puncture blood collection system and research on puncture force

Venous blood collection testing is one of the most commonly used medical diagnostic methods. Compared with conventional venous blood collection, robotic collection can reduce needle-stick injuries, medical staff workload, and infection risk; allow doctor-patient isolation; and improve collection reliability. Existing venous blood collection robots use rigid puncture needles, which can easily puncture the lower wall of blood vessels, causing vessel damage and collection failure. This paper proposes a bionic blood collection strategy based on a composite puncture needle that mimics the structure and function of mosquito mouthparts. A bionic composite puncture needle insertion system with puncture-force sensing was designed, and venipuncture forces were simulated and mathematically modelled. A prototype insertion system was built and used in an experiment, which demonstrated effective composite puncture blood collection and explored the factors influencing puncture force. Puncture force decreases with increased puncture speed and angle and with a decreased needle diameter. This provides a basis for optimising the parameters of blood collection robots.

Efficacy and Safety of Plastic Cannulae Compared with Metal Needles in the Initial Use of an Arteriovenous Fistulae in Incident Hemodialysis Patients: A Randomized Controlled Study

INTRODUCTION

Successful cannulation of an arteriovenous fistula (AVF) is important in patients starting hemodialysis (HD). Metal needles have been used for decades, but the usefulness of plastic cannulae has recently been demonstrated as a new technique.

METHODS

This was a prospective, randomized, open-label study of incident HD patients. Eligible patients were randomized into 2 groups in a 1:1 ratio (n = 45/group). Maturation of the AVF was confirmed using Doppler ultrasound prior to first needling, and 2 well-trained nurses implemented the AVF cannulation. The primary endpoint was the initial cannulation failure rate, defined as the failure of successful completion of 3 consecutive dialysis sessions. The secondary endpoints were time for hemostasis at the end of HD, degree of patients' pain, degree of cannulation difficulty felt by the nursing staffs, and achieving optimal HD adequacy.

RESULTS

The mean elapsed time from AVF creation to the first cannulation was 48.1 ± 16.7 days. A total of 17 cases of cannulation failure occurred, and the failure risk tended to be higher in the metal needle group than the plastic cannula group (hazard ratio 2.6, 95% confidence interval 0.95-7.41) after adjusting for age, gender, comorbidities, and AVF location. The overall incidence of vessel injury was higher and time for hemostasis was significantly longer in the metal group than the plastic group. The use of plastic cannula was associated with a better HD adequacy compared to a metal needle. However, the patients' pain score (p = 0.004) and nursing staff's cannulation difficulty score (p = 0.084) were higher in the plastic group, emphasizing the great importance of practice using plastic cannulae.

CONCLUSION

The vascular outcomes of plastic cannulae were much favorable compared to metal needles in incident HD patients. The use of plastic cannulae could be a new and innovative way to improve the quality of dialysis.

Renal Association Clinical Practice Guideline on Haemodialysis

This guideline is written primarily for doctors and nurses working in dialysis units and related areas of medicine in the UK, and is an update of a previous version written in 2009. It aims to provide guidance on how to look after patients and how to run dialysis units, and provides standards which units should in general aim to achieve. We would not advise patients to interpret the guideline as a rulebook, but perhaps to answer the question: "what does good quality haemodialysis look like?"The guideline is split into sections: each begins with a few statements which are graded by strength (1 is a firm recommendation, 2 is more like a sensible suggestion), and the type of research available to back up the statement, ranging from A (good quality trials so we are pretty sure this is right) to D (more like the opinion of experts than known for sure). After the statements there is a short summary explaining why we think this, often including a discussion of some of the most helpful research. There is then a list of the most important medical articles so that you can read further if you want to - most of this is freely available online, at least in summary form.A few notes on the individual sections: 1. This section is about how much dialysis a patient should have. The effectiveness of dialysis varies between patients because of differences in body size and age etc., so different people need different amounts, and this section gives guidance on what defines "enough" dialysis and how to make sure each person is getting that. Quite a bit of this section is very technical, for example, the term "eKt/V" is often used: this is a calculation based on blood tests before and after dialysis, which measures the effectiveness of a single dialysis session in a particular patient. 2. This section deals with "non-standard" dialysis, which basically means anything other than 3 times per week. For example, a few people need 4 or more sessions per week to keep healthy, and some people are fine with only 2 sessions per week - this is usually people who are older, or those who have only just started dialysis. Special considerations for children and pregnant patients are also covered here. 3. This section deals with membranes (the type of "filter" used in the dialysis machine) and "HDF" (haemodiafiltration) which is a more complex kind of dialysis which some doctors think is better. Studies are still being done, but at the moment we think it's as good as but not better than regular dialysis. 4. This section deals with fluid removal during dialysis sessions: how to remove enough fluid without causing cramps and low blood pressure. Amongst other recommendations we advise close collaboration with patients over this. 5. This section deals with dialysate, which is the fluid used to "pull" toxins out of the blood (it is sometimes called the "bath"). The level of things like potassium in the dialysate is important, otherwise too much or too little may be removed. There is a section on dialysate buffer (bicarbonate) and also a section on phosphate, which occasionally needs to be added into the dialysate. 6. This section is about anticoagulation (blood thinning) which is needed to stop the circuit from clotting, but sometimes causes side effects. 7. This section is about certain safety aspects of dialysis, not seeking to replace well-established local protocols, but focussing on just a few where we thought some national-level guidance would be useful. 8. This section draws together a few aspects of dialysis which don't easily fit elsewhere, and which impact on how dialysis feels to patients, rather than the medical outcome, though of course these are linked. This is where home haemodialysis and exercise are covered. There is an appendix at the end which covers a few aspects in more detail, especially the mathematical ideas. Several aspects of dialysis are not included in this guideline since they are covered elsewhere, often because they are aspects which affect non-dialysis patients too. This includes: anaemia, calcium and bone health, high blood pressure, nutrition, infection control, vascular access, transplant planning, and when dialysis should be started.

First-in-human evaluation of a hand-held automated venipuncture device for rapid venous blood draws

Obtaining venous access for blood sampling or intravenous (IV) fluid delivery is an essential first step in patient care. However, success rates rely heavily on clinician experience and patient physiology. Difficulties in obtaining venous access result in missed sticks and injury to patients, and typically require alternative access pathways and additional personnel that lengthen procedure times, thereby creating unnecessary costs to healthcare facilities. Here, we present the first-in-human assessment of an automated robotic venipuncture device designed to safely perform blood draws on peripheral forearm veins. The device combines ultrasound imaging and miniaturized robotics to identify suitable vessels for cannulation and robotically guide an attached needle toward the lumen center. The device demonstrated results comparable to or exceeding that of clinical standards, with a success rate of 87% on all participants (n = 31), a 97% success rate on nondifficult venous access participants (n = 25), and an average procedure time of 93 ± 30 s (n = 31). In the future, this device can be extended to other areas of vascular access such as IV catheterization, central venous access, dialysis, and arterial line placement.

Arteriovenous fistulas ipsilateral to internal jugular catheters for hemodialysis have decreased patency rates

PURPOSE

This study aimed to evaluate the effects of hemodialysis catheters on the survival of subsequent arteriovenous fistulas, according to the relative localization to the catheters.

METHODS

A total of 201 patients who initiated dialysis therapy using a hemodialysis catheter were eligible for this retrospective study. Arteriovenous fistulas were created on the nondominant upper extremity after the placement of hemodialysis catheters. The catheters were removed after four consecutive successful dialyses via arteriovenous fistulas. The effective factors on arteriovenous fistula failure were determined in and the prognostic factors for survival were modeled by regression analysis.

RESULTS

The relative placement of catheters as ipsi- or contralateral was found to significantly affect the survival of the arteriovenous fistulas. The overall survival was significantly longer in the contralateral arteriovenous fistula group (778.7 ± 28.8 vs. 247.3 ± 26.1 days; p < 0.001). The independent predictors of arteriovenous fistula survival were found to be relative side of arteriovenous fistula and hemodialysis catheter, age, and the presence of hypertension in multivariate analyses.

CONCLUSION

This study showed that ipsilateral localization of the catheters and arteriovenous fistulas negatively affect the cumulative arteriovenous fistula survival. Therefore, to improve vascular access survival, side of catheters or arteriovenous fistulas should always be considered.

Post-operative arterio-venous fistula blood flow influences primary and secondary patency following access surgery

PURPOSE

Primary arteriovenous fistula arterio venous fistula (AVF) formation has proven to be the best and optimal vascular access for the majority of haemodialysis patients. At present there are limited data to suggest which haemodynamic parameters most correlate with the likelihood of early failure. The aim of this study is to identify the haemodynamic predictors of early failure, hence identify which fistulae may benefit from timely pre-emptive intervention.

MATERIAL AND METHODS

Retrospective analysis of data was performed of 201 patients undergoing native AVF creation over a one year period. Demographic details, co-morbidity, preoperative vessel calibre were collected. Flow was measured by duplex ultrasound post operatively.

RESULTS

Preoperative vein calibre (p = 0.01) and fistula flow (p < 0.001) positively affected primary patency. Age, gender, ethnicity, type of fistula, hypertension and preoperative arterial calibre did not influence outcome. Regression analysis showed that the strength of correlation between early postoperative fistula flow and patency decreased progressively with time. Six week flow predicts early, but not late, failure. ROC analysis identified 300 ml/min flow as the best predictor of patency. Fistulae with flow above 300 ml/min were more likely to remain patent over the next 12 months (p < 0.001, HR = 7.4).

CONCLUSION

Postoperative fistula flow of less than 300 ml/min identifies AVFs at high risk of early failure. These may be candidates for early intervention with balloon assisted maturation. The findings of this retrospective cohort study strongly support the need for a more robust prospectively designed trial identifying haemodynamic factors that can predict mid and long-term AVF patency.

Fistula Cannulation with a Novel Fistula Cannula: A Review of Cannulation Devices and Procedures

Arteriovenous fistula cannulation for dialysis treatments in Europe has traditionally been done by metal needles. In ­Japan, plastic cannulas have been available for many years and are used in the majority of the dialysis patients. The mechanical structure and the cannulation procedure of the plastic cannulas differ from those of the metal needles. These differences are particularly beneficial for patients with delicate fistulas, tortuous vessels, metal allergies, oligophrenic patients, and also for the safety of the medical staff. In this paper, we present the main features of a novel fistula plastic cannula and the innovations introduced by it compared to the traditional metal needles.

Investigation of the knowledge and attitudes of patients who are undergoing hemodialysis treatment regarding their arteriovenous fistula

Purpose

The major cause of morbidity in hemodialysis patients is arteriovenous fistula deficiency. The patient should have adequate knowledge to ensure arteriovenous fistula patency. Our aim is to investigate the knowledge and attitude of the patients undergoing hemodialysis treatment regarding arteriovenous fistula.

Methods

This study was conducted on 335 patients who met the study criteria. Data collection forms evaluating the “Socio-Demographic and Medical Characteristics” and “Knowledge and Attitudes about arteriovenous fistula” of the patients were developed following a literature review by the investigators.

Results

The rules most known and implemented were “to not measure blood pressure” and “to not draw blood from arms with fistula”, while the least known and implemented were “to use blood vessels on the hands in arms without fistula for intravenous intervention” and “to know which situations cause hypotension”.

Conclusions

Hemodialysis patients with arteriovenous fistulas need to know that developing self-care behavior is a means to reconcile lifestyles with current health status. Accordingly, planned training in self-care should be provided to hemodialysis patients and their families, and nurses should repeat information to patients who demonstrate a lack of knowledge.

Real-time Needle Steering in Response to Rolling Vein Deformation by a 9-DOF Image-Guided Autonomous Venipuncture Robot

Venipuncture is the most common invasive medical procedure performed in the United States and the number one cause of hospital injury. Failure rates are particularly high in pediatric and elderly patients, whose veins tend to deform, move, or roll as the needle is introduced. To improve venipuncture accuracy in challenging patient populations, we have developed a portable device that autonomously servos a needle into a suitable vein under image guidance. The device operates in real time, combining near-infrared and ultrasound imaging, computer vision software, and a 9 degrees-of-freedom robot that servos the needle. In this paper, we present the kinematic and mechanical design of the latest generation robot. We then investigate in silico and in vitro the mechanics of vessel rolling and deformation in response to needle insertions performed by the robot. Finally, we demonstrate how the robot can make real-time adjustments under ultrasound image guidance to compensate for subtle vessel motions during venipuncture.

Brachial-cephalic fistula recovered with drainage for the basilic vein: Case report

Vascular access is essential for the implementation of hemodialysis (HD). The arteriovenous fistula (AVF) can be constructed in various locations using various veins. However, the quality of the veins will influence the construction site, as well as the functioning of the AVF. Careful analysis of the vascular network allows options for the development of new fistulas presentations. We present and discuss the case of a woman aged 69 years in HD in which a brachial-cephalic fistula with drainage to basilic vein was created, through rotation of the cephalic vein on the forearm level. This kind of access serves to prolong the time spent dialyzing through native fistulae, with their reduced complications and greater cost-effectiveness.

Hemodialysis Catheter-related Infection: Prophylaxis, Diagnosis and Treatment

Purpose

Infectious complications associated with central venous catheters (CVCs) are a major source of morbidity and mortality among hemodialysis (HD) patients. This review aims to discuss prevention, diagnosis criteria and management of CVC-related infections in HD patients.

Methods

We searched Medline for articles published in the last 10 years, with the keywords “catheter,” “hemodialysis,” “infection,” “treatment,” “diagnosis,” “prophylaxis” and “adults.” Only English language articles were reviewed. We reviewed prophylaxis and surveillance protocols, diagnosis criteria, including new molecular tools, and the management of catheter-related infections, including antibiotic regimen, empiric and according to causal agents, lock therapy, catheter salvage or removal choice and treatment of complications.

Results

To prevent infectious complications, first of all we need to avoid using catheters. If we need CVC, adoption of prophylaxis and surveillance protocols, and antibiotic ointment at the exit site reduce infectious complications. The diagnosis of CVC-related infections should be made with drainage and/or blood cultures. Empiric systemic antibiotics should cover Gram-positive and -negative microorganisms, and final regimen should be based on culture results. In selected cases, salvage of site, by CVC exchange over wire, or salvage of catheter, using antibiotic lock, under the cover of systemic antibiotics, could be attempted.

Conclusions

The best approach to prevent CVC-related infection would be to avoid the use of CVC. However, in patients for whom it is impossible, the adoption of adequate prophylaxis protocols, early diagnosis and effective treatment of infectious complications are essential to improve outcomes.

One-stage vs. two-stage brachio-basilic arteriovenous fistula for dialysis access: a systematic review and a meta-analysis

Introduction

A brachiobasilic arteriovenous fistula (BB-AVF) can provide access for haemodialysis in patients who are not eligible for a more superficial fistula. However, it is unclear whether one- or two-stage BB-AVF is the best option for patients.

Aim

To systematically assess the difference between both procedures in terms of access maturation, patency and postoperative complications.

Methods

Online search for randomised controlled trials (RCTs) and observational studies that compared the one-stage versus the two-stage technique for creating a BB-AVF.

Results

Eight studies were included (849 patients with 859 fistulas), 366 created using a one-stage technique, while 493 in a two-stage approach. There was no statistically significant difference between the two groups in the rate of successful maturation (Pooled risk ratio = 0.95 [0.82, 1.11], P = 0.53). Similarly, the incidence of postoperative haematoma (Pooled risk ratio = 0.73 [0.34, 1.58], P = 0.43), wound infection (Pooled risk ratio = 0.77 [0.35, 1.68], P = 0.51) and steal syndrome (Pooled risk ratio = 0.65 [0.27, 1.53], P = 0.32) were statistically comparable.

Conclusion

Although more studies seem to favour the two-stage BVT approach, evidence in the literature is not sufficient to draw a final conclusion as the difference between the one-stage and the two-stage approaches for creation of a BB-AVF is not statistically significant in terms of the overall maturation rate and postoperative complications. Patency rates (primary, assisted primary and secondary) were comparable in the majority of studies. Large randomised properly conducted trials with superior methodology and adequate sub-group analysis are needed before making a final recommendation.

The role of venous diameter in predicting arteriovenous fistula maturation: when not to expect an AVF to mature according to pre-operative vein diameter measurements? A best evidence topic

This best evidence topic was investigated according to a described protocol. We asked the question: what is the minimal vein diameter that can successfully predict maturation of an arteriovenous fistula (AVF) in patients undergoing dialysis. Using the reported search 804 papers were found, of which five represented the best evidence to answer the clinical question. All studies assessed the association between successful AVF maturation and the size of vein used. The strongest evidence came from a nonrandomised controlled follow-up study in which 76% of fistulas created using >2 mm cephalic vein successfully matured compared to 16% when the vein measured ≤2 mm. Another prospective, multicentre study showed 65% successful maturation using veins >4 mm compared to 45% with veins <3 mm. Vein diameter was found to be an independent predictor of maturation in multivariate regression analysis in two retrospective observational studies. Another retrospective observational study found that using venous measurements of ≥2.5 mm following tourniquet application resulted in more fistulas been created that would have otherwise been denied based on venous ultrasound mapping. A large multicentre randomised clinical trial assessing the use of different vein sizes both with and without tourniquet application using proper statistical tools - such as receiver operating characteristic - is required to make a final recommendation. Until then, a vein diameter of <2.5 mm should be considered inadequate for formation of an AVF, particularly if those measurements remain unchanged following the use of tourniquet.

Role of far infra-red therapy in dialysis arterio-venous fistula maturation and survival: systematic review and meta-analysis

INTRODUCTION

A well-functioning arteriovenous fistula (AVF) is the best modality for vascular access in patients with end-stage renal disease (ESRD) requiring haemodialysis (HD). However, AVFs' main disadvantage is the high rate of maturation failure, with approximately one third (20%-50%) not maturing into useful access. This review examine the use of Far-Infra Red therapy in an attempt to enhance both primary (unassisted) and secondary (assisted) patency rates for AVF in dialysis and pre-dialysis patients.

METHOD

We performed an online search for observational studies and randomised controlled trials (RCTs) that evaluated FIR in patients with AVF. Eligible studies compared FIR with control treatment and reported at least one outcome measure relating to access survival. Primary patency and secondary patency rates were the main outcomes of interest.

RESULTS

Four RCTs (666 patients) were included. Unassisted patency assessed in 610 patients, and was significantly better among those who received FIR (228/311) compared to (185/299) controls (pooled risk ratio of 1.23 [1.12-1.35], p = 0.00001). In addition, the two studies which reported secondary patency rates showed significant difference in favour of FIR therapy--160/168 patients--compared to 140/163 controls (pooled risk ratio of 1.11 [1.04-1.19], p = 0.003).

CONCLUSION

FIR therapy may positively influence the complex process of AVF maturation improving both primary and secondary patency rates. However blinded RCTs performed by investigators with no commercial ties to FIR therapy technologies are needed.

Portable robot for autonomous venipuncture using 3D near infrared image guidance

Venipuncture is pivotal to a wide range of clinical interventions and is consequently the leading cause of medical injury in the U.S. Complications associated with venipuncture are exacerbated in difficult settings, where the rate of success depends heavily on the patient's physiology and the practitioner's experience. In this paper, we describe a device that improves the accuracy and safety of the procedure by autonomously establishing a peripheral line for blood draws and IV's. The device combines a near-infrared imaging system, computer vision software, and a robotically driven needle within a portable shell. The device operates by imaging and mapping in real-time the 3D spatial coordinates of subcutaneous veins in order to direct the needle into a designated vein. We demonstrate proof of concept by assessing imaging performance in humans and cannulation accuracy on an advanced phlebotomy training model.

Blood Loss through AV Fistula: A Case Report and Literature Review

Little has been written about acute blood loss from hemodialysis vascular access. We describe a 57-year-old Caucasian male with an approximately 7 gm/dL drop in hemoglobin due to bleeding from a ruptured aneurysm in his right brachiocephalic arteriovenous fistula (AVF). There was no evidence of fistula infection. The patient was successfully managed by blood transfusions and insertion of a tunneled dialysis catheter for dialysis access. Later, the fistula was ligated and a new fistula was constructed in the opposite arm. Aneurysm should be considered in cases of acute vascular access bleeding in chronic dialysis patients.

Prevention of infection in patients with chronic kidney disease. Part II: healthcare-associated infections

This second article, in a three-part CE series on the prevention of infection in patients with chronic kidney disease, focuses on healthcare-associated infections and blood borne viruses that are prevalent within the haemodialysis environment. It also informs the reader of the relevant infection and prevention precaution guidelines and their application within a haemodialysis setting.