Introduction To assess the impact of the COVID-19 pandemic impact on haemodialysis centres, The Dialysis Outcomes and Practice Patterns Study and International Society of Nephrology (ISN) collaborated on a web-survey of centres. Methods A combined approach of random sampling and open invitation was used between March 2020 and March 2021. Responses were obtained from 412 centres in 78 countries and all 10 ISN regions. Results In 8 regions, rates of SARS-CoV-2 infection were <20% in most centres, but in North East Asia and Newly Independent States and Russia rates were ≥20% and ≥30%, respectively. Mortality was ≥10% in most centres in 8 regions, though lower in North America and Caribbean and North East Asia. Diagnostic testing was not available in 33%, 37%, and 61% of centres in Latin America, Africa, and East and Central Europe, respectively. Surgical masks were widely available, but severe shortages of particulate-air filter masks were reported in Latin America (18%) and Africa (30%). Rates of infection in staff ranged from 0% in 90% of centres in North East Asia to ≥50% in 63% of centres in the Middle East and 68% of centres in Newly Independent States and Russia. In most centres <10% of staff died, but in Africa and South Asia 2% and 6% of centres reported ≥50% mortality, respectively. Conclusion There has been wide global variation in SARS-CoV-2 infection rates amongst haemodialysis patients and staff, PPE availability, and testing, and the ways in which services have been redesigned in response to the pandemic.

Introduction: Recurrent hemodialysis (HD)-induced ischemia has emerged as a mechanism responsible for cognitive impairment in HD patients. Impairment of cerebrovascular function in HD patients may render the brain vulnerable to HD-induced ischemic injury. Cerebrovascular reactivity to CO 2 (CVR) is a noninvasive marker of cerebrovascular function. Whether CVR is impaired in HD patients is unknown. In this study, we compared CVR between healthy participants, HD patients, and chronic kidney disease (CKD)patients not yet requiring dialysis.Methods: This was a single-center prospective observational study carried out at Kidney Clinical Research Unit in London, Canada. We used carefully controlled hypercapnia to interrogate brain vasomotor control. Transcranial Doppler was combined with 10-mm Hg step changes in CO 2 from baseline to hypercapnia (intervention) and back to baseline (recovery) to assess CVR in 8 HD, 10 CKD, and 17 heathy participants.Results: HD patients had lower CVR than CKD or healthy participants during both intervention and recovery (P < 0.0001). There were no differences in CVR between healthy and CKD participants during either intervention (P ¼ 0.88) or recovery (P ¼ 0.99). The impaired CVR in HD patients was independent of CO 2induced changes in blood pressure, heart rate, cardiac output, or dialysis vintage. In the CKD group, CVR was not associated with the estimated glomerular filtration rate.Conclusions: Our study shows that HD patients have impaired CVR relative to CKD and healthy participants. This renders HD patients vulnerable to ischemic injury during circulatory stress of dialysis and may contribute to the pathogenesis of cognitive impairment.