COVID-19 often leads to acute respiratory distress syndrome complicated by acute kidney injury (AKI). The indications for renal replacement therapy for these patients are those commonly accepted to treat AKI. We describe a continuous veno-venous haemodialysis (CVVHD) protocol for AKI, which aims to provide the best treatment according to the particular patient’s and medical personnels’ needs in biohazard settings with limited human and technological resources. We designed a CVVHD protocol with a high cut-off (HCO) filter in regional citrate anticoagulation (RCA). The HCO filter in diffusion determines the enhanced cytokines clearance with less filter clotting due to a lower filtration fraction. In our hospital, at the beginning of the pandemic outbreak, we treated seven COVID-19 patients with AKI stage 2 and 3 and recorded the circuit lifespan and the number of interventions on monitors. CVVHD in RCA appears to be safe, effective and easy to be performed in a biohazard scenario using lower blood flows and less bag changes with fluid savings, a biohazard reduction and sparing of resources. Although the data come from a very small cohort, our protocol seems related to a low mortality.

Despite limited organ availability and post-transplant complications, kidney transplantation remains the optimal treatment for End-Stage Kidney Disease (ESKD). However, innovative dialysis technologies such as portable, wearable, and implantable bioartificial kidney systems are being developed with the aim of addressing these issues and improving patient care. An ideal implantable device could combine bioreactors and blood ultrafiltration to replicate key native cell functions for solute reabsorption, secretion, and endocrinologic activities. Today, the feasibility of an implantable bioreactor for renal cell therapy opens the challenge of developing a fully implantable bioartificial kidney based on silicon nanopore membranes to ensure immunological isolation, cell viability, and the possibility of maintaining a blood substrate for metabolic activities. Current technology is not sufficient to obtain an efficient artificial bioreactor to reach physiological blood purification, which requires a more complex system to produce an ultrafiltrate from the blood that can be processed by cells and eliminated as urine. The number of cells in the bioreactor, endocrine activity, immunological cell isolation, solute and fluid secretion/reabsorption, cell viability, blood and ultrafiltration flow control, and thrombogenicity are fundamental issues that require a new technology that today appears to be a challenge for the design of an implantable artificial kidney. This review aims to analyze the state of the art in this particular field of kidney replacement therapy to highlight the current limitations and possible future technology developments to create implanted and wearable organs capable of treating ESKD with artificial organs that can replicate all native kidneys functions.

The key role of arterial hypertension in chonic kidney disease (CKD) progression is widely recognized, but its contribution to tubulointerstitial damage (TID) in glomerulonephritis (GN) remains uncertain. Hence, the objective of this study is to clarify whether TID is associated with glomerular damage, and whether the damage at the tubulointerstitial compartment is more severe in hypertensive patients. The study included retrospectively consecutive patients referred to the Nephrology Unit with diagnoses of primary glomerulonephritis, lupus nephritis (LN), and nephroangiosclerosis (NAS) at biopsy. At least six glomeruli per biopsy were analysed through light and immunofluorescence microscopy. Global glomerulosclerosis (GGS%), TID, and arteriolar hyalinosis (AH) were used as markers of CKD severity. Of the 448 patients of the cohort, 403 received a diagnosis of GN, with the remaining being diagnosed with NAS. Hypertension was found in 52% of the overall patients, with no significant differences among those with GN, and reaching 88.9% prevalence rate in NAS. The hypertensive patients with GN had more marked damage in glomerular and tubular compartments than normotensives independently of the amount of proteinuria. Moreover, hypertension and GGS% were found to be strongly associated with TID in GN. In GN patients, not only the severity of glomerular damage but also the extent of TID was associated with high blood pressure.

Critical patients with Acute Kidney Injury (AKI) requiring renal replacement therapy are in most cases eligible only for continuous modalities where the electrolyte balance control is a critical issue. The standard solutions used for hemodiafiltration, containing potassium at 2 mmol/L and no phosphorus, determines during the extended renal replacement therapy hypokalemia and hypophosphatemia. Therefore, solutions containing potassium and phosphate in physiological concentrations were formulated to avoid electrolyte imbalances and reduce ion alterations in prolonged treatments, these solutions are not routinely used in the standard clinical practice. To avoid electrolyte imbalances, we have first introduced in our practice two different solutions and then we have retrospectively analyzed the electrolyte balance upon these two solutions in order to identity the impact of these solutions on potassium and phosphate according to our clinical practice. We retrospectively analyzed 96 patients treated with Continuous Renal Replacement Therapy (CRRT) in the intensive care units (ICU) at Padua’s University Hospital to evaluate the role on electrolyte balance of Phoxilium^® and Prismasol 2^® that differ in their composition and the need for electrolytes infusions. In the Phoxilium group the frequency of hypokalemia, hypophosphatemia, and the need of potassium and phosphate replacement were significantly reduced resulting in a reduction in complications, workload, and clinical risk associated with infusions of electrolytes. Our data demonstrated that the use of these two different hemodiafiltration solutions can reduce the occurrence of hypokalemia and hypophosphatemia during CRRT performing personalized treatments without the use of potassium and phosphate infusions.

Background: The possibility of keeping liver grafts viable and functioning until transplantation has been explored since the 1950s. However, the current modalities of Normothermic Machine Perfusion (NMP) have shown several limitations, such as the inability to correct electrolytes and pH derangements efficiently. Combining NMP with continuous kidney replacement therapy (CKRT) might provide a promising new model to overcome these issues. Methods: An NMP that covers the organ perfusion, oxygenation, carbon dioxide removal, and thermal balance was connected to a CKRT circuit to ensure physiological hydro-electrolytes, acid–base balance, and catabolite removal from the perfusate. Results: The integration of NMP and CKRT maintains a neoplastic liver in a perfusion system with physiological perfusate for 100 h. CKRT re-established and maintained the hydro-electrolyte and acid–base status throughout the 100 h of perfusion. Significant limitations were the need for frequent monitoring of electrolytes and acid–base disorders and the loss of low molecular weight nutrients, which have to be replenished by manual infusion into the system. Conclusions: This novel CKRT-NMP integrated system may represent a practical and versatile model to support organs’ perfusion and extend preservation times. Further experiments are needed to fix monitoring and adjusting processes.

Critical clinical forms of COVID-19 infection often include Acute Kidney Injury (AKI), requiring kidney replacement therapy (KRT) in up to 20% of patients, further worsening the outcome of the disease. No specific medical therapies are available for the treatment of COVID-19, while supportive care remains the standard treatment with the control of systemic inflammation playing a pivotal role, avoiding the disease progression and improving organ function. Extracorporeal blood purification (EBP) has been proposed for cytokines removal in sepsis and could be beneficial in COVID-19, preventing the cytokines release syndrome (CRS) and providing Extra-corporeal organ support (ECOS) in critical patients. Different EBP procedures for COVID-19 patients have been proposed including hemoperfusion (HP) on sorbent, continuous kidney replacement therapy (CRRT) with adsorbing capacity, or the use of high cut-off (HCO) membranes. Depending on the local experience, the multidisciplinary capabilities, the hardware, and the available devices, EBP can be combined sequentially or in parallel. The purpose of this paper is to illustrate how to perform EBPs, providing practical support to extracorporeal therapies in COVID-19 patients with AKI.