Pushing the Boundaries of Hemodialysis: Innovations in Membranes and Sorbents

ABSTRACT Membranes and sorbents play a crucial role in extracorporeal blood purification therapies, which aim to remove harmful molecules and toxins from the blood. Over the years, advancements in hemodialysis (HD) membranes and sorbents have significantly enhanced their safety and effectiveness. This review article will summarize the latest breakthroughs in the development and clinical application of HD membranes and sorbents. We will commence with a concise examination of the mechanisms involved in solute transport across membranes and sorbents. Subsequently, we will explore the evolutionary path of HD membranes, from early cellophane membranes to high-flux membranes, including the development of high-cut-off membranes and the emergence of medium- cut-off membranes. We will discuss each type of HD membrane's advantages and limitations, highlighting the most promising advancements in novel biomaterials and biocompatibility, technologies, research in membrane performance, and their clinical applications. Furthermore, we will delve into the evolution and progress of sorbent technology, tracing its historical development, outlining its key characteristics, examining the mechanism involved in the adsorption process, and exploring its clinical application. This review aims to underscore the growth and future landscape of HD membranes and sorbents in extracorporeal blood purification techniques.

Are Medium Cut-off Membranes the Future, or the Promising Reality for Chronic Hemodialysis Patients?

ABSTRACT The development of hemodialysis (HD) membranes has substantially advanced in the last decade. This has resulted in the manufacturing of medium cut-off membranes (MCO) whose internal architecture is based on greater pore size and a smaller diameter, thus promoting the clearance of particles of greater size as well as retrofiltration. Multiple studies have proven their efficacy in the clearance of uremic mid-sized molecules such as β2-microglobulin, free light chains, and some interleukins; this clearance is far superior with MCO membranes when compared with high-flux HD, and similar to that obtained with online hemodiafiltration. This review summarizes the results of the most relevant clinical studies of this membrane in terms of uremic toxin clearance, as well as the features of some clinical outcomes such as quality of life and hospitalizations.

Hybrid Therapies for Supporting Critically Ill Patients with Acute Kidney Injury: When, how, and for Whom?

ABSTRACT Acute kidney injury (AKI) is common in critically ill patients. There is no specific pharmacological treatment for established severe AKI. Therefore, the conventional therapeutic strategy is limited to the use of kidney replacement therapy (KRT) to maintain homeostasis. Hybrid therapies optimize the advantages of intermittent and continuous modalities of KRT, combining lower hourly efficiency, longer application time, at lesser cost, but also adding different physicochemical principles of extracorporeal clearance. The sum of convection and diffusion, with or without adsorption or apheresis, and in different time combinations gives hybrid techniques great flexibility in prescribing a personalized treatment adapted to the needs of each patient at any given time. Hybrid therapies are increasingly being used due to their flexibility, which is determined by the combination of equipment, membranes, and available resources (machines and health-care personnel experience). The required technology is widely available in most intensive care units and uses low-cost consumables compared to other types of AKI treatment modalities, favoring its widespread use. Hybrid therapies are feasible and provide a viable form of KRT, either alone or as a transition therapy from continuous kidney replacement therapy to intermittent hemodialysis.

Importance of Confirmatory Tests for Sars-Cov-2 Infection in Hemodialysis Patients: A Multicenter Mexican Registry

Abstract Background: Since the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, patients with chronic kidney disease vulnerable to suffering more severe COVID-19 disease and worse outcomes have been identified Objectives: Our study's aim was to determine the incidence, characteristics, and outcomes of SARS-CoV-2 infection in patients of hemodialysis (HD) units in Mexico and to describe the availability of confirmatory testing Methods: This study was multicentric study of 19 HD units, conducted between March 2020 and March 2021 Results: From a total of 5779 patients, 955 (16.5%) cases of suspicious COVID-19 were detected; a SARS-CoV-2 reverse transcription polymerase chain reaction test was done in only 50.6% of patients. Forty-five percentages were hospitalized and 6% required invasive mechanical ventilation (IMV). There was no significant difference in mortality between confirmed (131/483) and suspicious (124/472) cases (p = 0.74). The percentage of patients in need of hospitalization, IMV, and deceased was greater than in the rest of the study population Conclusions: The study revealed that 49.4% of the cases were not confirmed, a worrisome observation given that this is a highly vulnerable population (higher probability of contagion and worse outcomes), in which 100% of patients should have a confirmatory test

Acute Kidney Injury in Critical Care COVID-19 Patients on Invasive Mechanical Ventilation: The Potential Preventive Role of Dexamethasone

Abstract Background: A high incidence of acute kidney injury (AKI) has been reported in coronavirus disease 2019 (COVID-19) patients in critical care units and those undergoing invasive mechanical ventilation (IMV). The introduction of dexamethasone (DXM) as treatment for severe COVID-19 has improved mortality, but its effects in other organs remain under study. Objective: The objective of this study was to evaluate the association between DXM and AKI in COVID-19. Methods: In this prospective observational cohort study, we evaluated the incidence of AKI in critically ill COVID-19 patients undergoing mechanical ventilation, and the association of DXM treatment with the incidence, severity, and outcomes of AKI. The association between DXM treatment and AKI was evaluated by multivariable logistic regression. The association of the combination of DXM treatment and AKI on mortality was evaluated by Cox-regression analysis. Results: We included 552 patients. AKI was diagnosed in 311 (56%), of which 196 (63%) corresponded to severe (stage 2 or 3) AKI, and 46 (14.8%) received kidney replacement therapy. Two hundred and sixty-seven (48%) patients were treated with DXM. This treatment was associated to lower incidence of AKI (Odds Radio 0.34, 95% Confidence intervals [CI] 0.22-0.52, p < 0.001) after adjusting for age, body mass index, laboratory parameters, SOFA score, and vasopressor use. DXM treatment significantly reduced mortality in patients with severe AKI (HR 0.63, 95%CI 0.41-0.96, p = 0.032). Conclusions: The incidence of AKI is high in COVID-19 patients under IMV. DXM treatment is associated with a lower incidence of AKI and a lower mortality in the group with severe AKI.

What Did We Learn about Coronavirus Disease-19-Associated Acute Kidney Injury During the Pandemic?

ABSTRACT Initial reports suggested that kidney involvement after coronavirus disease 19 (COVID-19) infection was uncommon, but this premise appears to be incorrect. Acute kidney injury can occur through various mechanisms and complicate the course of up to 25% of patients with COVID-19 hospitalized in our Institution, and of over 50% of those on invasive mechanical ventilation. Mechanisms of injury include direct kidney injury and predominantly tubular, although glomerular injury has been reported, and resulting from severe hypoxic respiratory failure, secondary infection, and exposure to nephrotoxic drugs. The mainstay of treatment remains the prevention of progressive kidney damage and, in some cases, the use of renal replacement therapy. Although the use of blood purification techniques has been proposed as a potential treatment, results to date have not been conclusive. In this manuscript, the mechanisms of kidney injury by COVID-19, risk factors, and the mainstays of treatment are reviewed.

Prevención y control de la infección por coronavirus SARS-CoV-2 (Covid-19) en unidades de hemodiálisis / Prevention and control of SARS-CoV-2 (Covid-19) coronavirus infection in hemodialysis units

Resumen: La pandemia del SARS-CoV-2 representa un riesgo especial para los pacientes en hemodiálisis crónica por su estado de inmunosupresión, edad avanzada y coexistencia de comorbilidades importantes, en particular patología cardiovascular, diabetes mellitus y otras. Adicionalmente, esta población constituye un conglomerado cerrado ya que los pacientes acuden a tratamiento con regularidad y permanecen horas en los lugares de tratamiento, expuestos a una posible adquisición de la infección. El hecho de acudir necesaria y regularmente a su tratamiento impide que permanezcan en aislamiento domiciliario y con exposición potencial en el traslado. Las presentes recomendaciones resumen las intervenciones propuestas por tres organizaciones internacionales, a las que se agregan algunas sugeridas por expertos nacionales, con el objetivo de identificar precozmente a los pacientes y personal de la salud en riesgo para disminuir el riesgo de infección.

Abstract The SARS-CoV-2 pandemic is of hich risk for patients on chronic hemodialysis due to their immunosuppressed state, advanced age, and the coexistence of significant comorbidities, in particular cardiovascular disease, diabetes mellitus, and others. Additionally, they constitute a closed conglomerate since they come to treatment regularly, spending hours in the treatment places, exposed to a possible acquisition of the infection. Finally, going to their treatment regularly prevents them from remaining in home isolation and with potential exposure. These recommendations summarize the interventions proposed by three international organizations and add some suggested by national experts, with the aim to early identify the patients and health personnel at risk and reducing the risk of infection.

Prevalencia de polimorfismos del receptor de vitamina D en pacientes pediátricos mexicanos con enfermedad renal crónica / Prevalence of vitamin D receptor gene polymorphisms in Mexican children with chronic kidney disease

Introducción. La posible influencia de los diferentes polimorfismos del receptor de vitamina D sobre la regulación del eje calcio-hormona paratiroidea -vitamina D es particularmente importante en pacientes con enfermedad renal crónica, ya que cursan con trastornos en el metabolismo mineral óseo. El objetivo del trabajo fue describir la frecuencia de los polimorfismos rs7975232 (ApaI), rs731236 (TaqI) y rs1544410 (BsmI) en el receptor de vitamina D y su relación con el calcio, el fósforo, la fosfatasa alcalina y la hormona paratiroidea en pacientes pediátricos con enfermedad renal crónica. Métodos. Se incluyeron 31 pacientes con enfermedad renal crónica. Se tomaron muestras de sangre a cada uno para la determinación de marcadores bioquímicos y muestras de ADN para la genotipificación del gen del receptor a vitamina D utilizando el método de la reacción en cadena de la polimerasa y restricción enzimática. Resultados. La edad promedio de los pacientes fue de 15.6 ± 3.6 años. Para ApaI, fueron homocigotos AA siete pacientes (22.58%); Aa, 18 pacientes (58.06%) y AA, seis pacientes (19.35%). Para BsmI, 14 pacientes fueron BB (45.16%) y 17 pacientes fueron Bb (54.83%). Los pacientes BB tuvieron calcio sérico mayor que los Bb (p = 0.04). Para TaqI, fueron TT 19 pacientes (61.3%); Tt, once pacientes (35.48%) y uno, tt (3.22%). Aquellos con alelo t (Tt o tt) presentaron concentraciones de calcio sérico significativamente más bajas que el homocigoto TT. Conclusiones. Se reportaron las frecuencias de genotipos y alelos del receptor de vitamina D en niños mexicanos. Se obtuvieron valores de calcio sérico más elevados en aquellos con alelo BB o TT.

Background. The possible influence of vitamin D receptor (VDR) gene polymorphisms on the regulation of the calcium-parathyroid hormone-vitamin D axis is particularly important in end-stage renal disease (ESRD) patients due to alterations in bone mineral metabolism. The aim of the study was to describe the frequency of VDR gene polymorphisms rs7975232 (ApaI), rs731236 (TaqI), rs1544410 (BsmI) and their relationship with serum calcium, phosphate, alkaline phosphatase and parathyroid hormone in children with ESRD. Methods. Thirty one patients were included in the study. Blood samples were drawn for biochemical determinations and DNA extraction. VDR genotypes were analyzed as restriction fragment length polymorphisms using ApaI, BsmI and TaqI. Results. Mean age of the patients was 15.6 ± 3.6 years. For ApaI, seven patients were AA (22.58%), 18 patients were Aa (58.06%) and six patients were aa (19.35%). For BsmI, 14 patients were BB (45.16%) and 17 were Bb (54.83%). Patients who were homozygous for BB had higher serum calcium concentrations than Bb patients (p = 0.04). For TaqI, 19 patients were TT (61.3%), 11 were Tt (35.48%) and one was tt (3.22%). Those with t allele (Tt or tt) had serum calcium concentrations significantly lower than TT patients. Conclusions. Genotype and allele frequency of the VDR gene is reported in Mexican patients with ESRD. Those with BB or TT genotype had higher serum calcium concentrations.