No abstract

COVID-19, a disease caused by a novel coronavirus, is a major global human threat that has turned into a pandemic. This novel coronavirus has specifically high morbidity in the elderly and in comorbid populations. Uraemic patients on dialysis combine an intrinsic fragility and a very frequent burden of comorbidities with a specific setting in which many patients are repeatedly treated in the same area (haemodialysis centres). Moreover, if infected, the intensity of dialysis requiring specialized resources and staff is further complicated by requirements for isolation, control and prevention, putting healthcare systems under exceptional additional strain. Therefore, all measures to slow if not to eradicate the pandemic and to control unmanageably high incidence rates must be taken very seriously. The aim of the present review of the European Dialysis (EUDIAL) Working Group of ERA-EDTA is to provide recommendations for the prevention, mitigation and containment in haemodialysis centres of the emerging COVID-19 pandemic. The management of patients on dialysis affected by COVID-19 must be carried out according to strict protocols to minimize the risk for other patients and personnel taking care of these patients. Measures of prevention, protection, screening, isolation and distribution have been shown to be efficient in similar settings. They are essential in the management of the pandemic and should be taken in the early stages of the disease.

No abstract

Our prospective study shows that the relationship between Qa of AVFs and CO is complex and a third-order polynomial regression model best fits this relationship. Furthermore, it is the first study to clearly show the high predictive power for high-output cardiac failure occurrence of Qa cut-off values >or= 2.0 l/min.

Symptomatic intradialytic hypotension is a common complication of hemodialysis (HD). The application of convective therapies to the outpatient setting may improve outcomes, including intradialytic hypotension. In this multicenter, open-label, randomized controlled study, we randomly assigned 146 long-term dialysis patients to HD (n ϭ 70), online predilution hemofiltration (HF; n ϭ 36), or online predilution hemodiafiltration (HDF; n ϭ 40). The primary end point was the frequency of intradialytic symptomatic hypotension (ISH). Compared with the run-in period, the frequency of sessions with ISH during the evaluation period increased for HD (7.1 to 7.9%) and decreased for both HF (9.8 to 8.0%) and HDF (10.6 to 5.2%) (P Ͻ 0.001). Mean predialysis systolic BP increased by 4.2 mmHg among those who were assigned to HDF compared with decreases of 0.6 and 1.8 mmHg among those who were assigned to HD and HF, respectively (P ϭ 0.038). Multivariate logistic regression demonstrated significant risk reductions in ISH for both HF (odds ratio 0.69; 95% confidence interval 0.51 to 0.92) and HDF (odds ratio 0.46, 95% confidence interval 0.33 to 0.63). There was a trend toward higher dropout for those who were assigned to HF (P ϭ 0.107). In conclusion, compared with conventional HD, convective therapies (HDF and HF) reduce ISH in long-term dialysis patients.

An overall improvement in the treatment tolerance was observed with BVT, particularly intradialytic cardiovascular stability. Patients with the highest incidence of IDH during conventional HD and free from chronic pre-dialysis hypotension seem to respond better. Inter-dialysis symptoms also seem to improve with control of BV.

Clinically there are some autogenous arteriovenous fistulas (AVFs) that are obviously mature. The real problem in clinical evaluation is in predicting the ultimate outcome of AVFs that are not clearly mature. Thus it would be advantageous to develop objective quantitative criteria to be applied early after vascular access placement in order to evaluate the suitability of AVFs for dialysis. The goal of this study was to document the blood flow rate modifications that the construction and maturation of a radiocephalic wrist AVF produce in the brachial artery by means of duplex Doppler ultrasonography. All incident uremic patients who needed the construction of a radiocephalic wrist AVF in the last 9 months of 2003 were enrolled in the study: 18 patients underwent such an operation. A linear color Doppler ultrasound scan was performed with a 7.0 MHz imaging/5.0 MHz Doppler probe by sampling the brachial artery 2 cm above the elbow: the internal diameter of the artery was measured and its blood flow rate calculated just before AVF construction and 1, 7, 28 days, and at least 6 months after AVF construction. The internal diameter and blood flow rate of the brachial artery were, respectively, 4.3 +/- 0.7 mm and 56.1 +/- 19.2 ml/min at baseline. A new AVF was constructed in one patient whose brachial artery blood flow rate was 80.0 ml/min at 28 days. When excluding this AVF, the mean brachial artery blood flow rate of the 17 AVFs was 720.4 +/- 132.8 ml/min (median 750 ml/min, range 480-890 ml/min) at 28 days and 997.6 +/- 259.7 ml/min 258.0 +/- 63.0 days after AVF construction. When analyzing the percent increase in brachial artery blood flow rate of the 17 AVFs at the different time points, the most dramatic one occurred at day 1 compared to the baseline (549.0%; mean blood flow rate at day 1, 365.0 +/- 129.3 ml/min). Thus the blood flow rate at day 1 represents more than half (50.7%) of the blood flow rate that will be measured at day 28. Then the increase was less steep, with a 20.1% increase between day 7 and day 1 (mean blood flow rate at day 7, 438.4 +/- 86.0 ml/min), a 64.3% increase between day 28 and day 7, and a 38.5% increase at 258.0 +/- 63.0 days compared to 28 days. The present study was able to document the changes in brachial blood flow rate consequent to a radiocephalic wrist AVF maturation by means of duplex Doppler ultrasonography of the brachial artery. This measure may be helpful in monitoring which AVFs will probably fail. This screening should integrate clinical assessment, thus allowing sound judgment of the level of maturation of an AVF and of its outcome.

Abstract Intradialytic hypotension (IDH) is a frequent and serious complication of chronic haemodialysis, linked to adverse long-term outcomes including increased cardiovascular and all-cause mortality. IDH is the end result of the interaction between ultrafiltration rate (UFR), cardiac output and arteriolar tone. Thus excessive ultrafiltration may decrease the cardiac output, especially when compensatory mechanisms (heart rate, myocardial contractility, vascular tone and splanchnic flow shifts) fail to be optimally recruited. The repeated disruption of end-organ perfusion in IDH may lead to various adverse clinical outcomes affecting the heart, central nervous system, kidney and gastrointestinal system. Potential interventions to decrease the incidence or severity of IDH include optimization of the dialysis prescription (cool dialysate, UFR, sodium profiling and high-flux haemofiltration), interventions during the dialysis session (midodrine, mannitol, food intake, intradialytic exercise and intermittent pneumatic compression of the lower limbs) and interventions in the interdialysis period (lower interdialytic weight gain and blood pressure–lowering drugs). However, the evidence base for many of these interventions is thin and optimal prevention and management of IDH awaits further clinical investigation. Developing a consensus definition of IDH will facilitate clinical research. We review the most recent findings on risk factors, pathophysiology and management of IDH and, based on this, we call for a new consensus definition of IDH based on clinical outcomes and define a roadmap for IDH research.