Validation and applicability of an alternative method for dialysis water and dialysate quality analysis / Validação e aplicabilidade de um método alternativo para análise da qualidade da água e do dialisato em diálise

ABSTRACT Introduction: In hemodialysis, patients are exposed to a large volume of water, which may lead to fatal risks if not meeting quality standards. This study aimed to validate an alternative method for monitoring microbiological quality of treated water and assess its applicability in dialysis and dialysate analysis, to allow corrective actions in real-time. Methods: Validation and applicability were analyzed by conventional and alternative methods. For validation, E. coli standard endotoxin was diluted with apyrogenic water in five concentrations. For the applicability analysis, treated water for dialysis was collected from different points in the treatment system (reverse osmosis, drainage canalization at the storage tank bottom, reuse, and loop), and dialysate was collected from four machines located in different rooms in the hemodialysis sector. Results: The validation results were in accordance with the Brazilian Pharmacopoeia acceptance criteria, except for the last two concentrations analyzed. In addition, the ruggedness criterion performed under the US Pharmacopoeia was in agreement with the results. Discussion: A limiting factor in the applicability analysis was the absence of the endotoxin maximum permitted level in dialysate by the Brazilian legislation. When comparing the analysis time, the alternative method was more time-consuming than the conventional one. This suggests that the alternative method is effective in the case of few analyses, that is, real-time analyses, favoring corrective actions promptly. On the other hand, it does not support the implementation of the alternative method in a laboratory routine due to the high demand for analyses.

RESUMO Introdução: Na hemodiálise, os pacientes são expostos a um grande volume de água, o que pode levar a riscos fatais se não cumprir com padrões de qualidade. Este estudo teve como objetivo validar um método alternativo para monitorar a qualidade microbiológica da água tratada e avaliar sua aplicabilidade em análises de diálise e dialisato, para permitir ações corretivas em tempo real. Métodos: A validação e aplicabilidade foram analisadas por métodos convencionais e alternativos. Para validação, a endotoxina padrão de E. coli foi diluída com água apirogênica em cinco concentrações. Para a análise de aplicabilidade, a água tratada para diálise foi coletada em diferentes pontos do sistema de tratamento (osmose reversa, canalização de drenagem no fundo do tanque de armazenamento, reutilização e circuito) e o dialisato foi coletado em quatro máquinas localizadas em diferentes salas do setor de hemodiálise. Resultados: Os resultados da validação obedeceram aos critérios de aceitação da Farmacopeia Brasileira, com exceção das duas últimas concentrações analisadas. Além disso, o critério de robustez realizado sob a Farmacopeia dos EUA estava de acordo com os resultados. Discussão: Um fator limitante na análise de aplicabilidade foi a ausência do nível máximo permitido de endotoxina no dialisato pela legislação brasileira. Ao comparar o tempo de análise, o método alternativo consumiu mais tempo que o convencional. Isso sugere que o método alternativo é eficaz no caso de poucas análises, ou seja, análises em tempo real, favorecendo ações corretivas imediatamente. Por outro lado, não suporta a implementação do método alternativo em uma rotina de laboratório devido à alta demanda por análises.

Fluid and hemodynamic management in hemodialysis patients: challenges and opportunities / Manejo hídrico e hemodinâmico em pacientes em hemodiálise: desafios e oportunidades

Abstract Fluid volume and hemodynamic management in hemodialysis patients is an essential component of dialysis adequacy. Restoring salt and water homeostasis in hemodialysis patients has been a permanent quest by nephrologists summarized by the 'dry weight' probing approach. Although this clinical approach has been associated with benefits on cardiovascular outcome, it is now challenged by recent studies showing that intensity or aggressiveness to remove fluid during intermittent dialysis is associated with cardiovascular stress and potential organ damage. A more precise approach is required to improve cardiovascular outcome in this high-risk population. Fluid status assessment and monitoring rely on four components: clinical assessment, non-invasive instrumental tools (e.g., US, bioimpedance, blood volume monitoring), cardiac biomarkers (e.g. natriuretic peptides), and algorithm and sodium modeling to estimate mass transfer. Optimal management of fluid and sodium imbalance in dialysis patients consist in adjusting salt and fluid removal by dialysis (ultrafiltration, dialysate sodium) and by restricting salt intake and fluid gain between dialysis sessions. Modern technology using biosensors and feedback control tools embarked on dialysis machine, with sophisticated analytics will provide direct handling of sodium and water in a more precise and personalized way. It is envisaged in the near future that these tools will support physician decision making with high potential of improving cardiovascular outcome.

Resumo O volume de fluidos e o controle hemodinâmico em pacientes em hemodiálise é um componente essencial da adequação da diálise. A restauração da homeostase do sal e da água em pacientes em hemodiálise tem sido uma busca constante por parte dos nefrologistas, no que condiz à abordagem do "peso seco. Embora essa abordagem clínica tenha sido associada a benefícios no desfecho cardiovascular, recentemente tem sido questionada por estudos que mostram que a intensidade ou agressividade para remover fluidos durante a diálise intermitente está associada a estresse cardiovascular e dano potencial a órgãos.para remover fluidos durante a diálise intermitente está associada a estresse cardiovascular e dano potencial a órgãos. Uma abordagem mais precisa é necessária para melhorar o desfecho cardiovascular nessa população de alto risco. A avaliação e monitorização do estado hídrico baseiam-se em quatro componentes: avaliação clínica, ferramentas instrumentais não invasivas (por exemplo, US, bioimpedância, monitorização do volume sanguíneo), biomarcadores cardíacos (e.g. peptídeos natriuréticos), algoritmos e modelagem de sódio para estimar a transferência de massa. O manejo otimizado do desequilíbrio hídrico e de sódio em pacientes dialíticos consiste em ajustar a remoção de sal e líquido por diálise (ultrafiltração, dialisato de sódio), e restringir a ingestão de sal e o ganho de líquido entre as sessões de diálise. Tecnologia moderna que utiliza biosensores e ferramentas de controle de feedback, hoje parte da máquina de diálise, com análises sofisticadas, proporcionam o manejo direto sobre o sódio e a água de uma maneira mais precisa e personalizada. Prevê-se no futuro próximo que essas ferramentas poderão auxiliar na tomada de decisão do médico, com alto potencial para melhorar o resultado cardiovascular.

Effect of standard and neutral-pH peritoneal dialysis solutions upon fibroblasts proliferation / Efeito da solução de diálise peritoneal com pH neutro e padrão sobre a proliferação de fibroblastos

Introduction: Continuous exposition of the peritoneal membrane to conventional dialysis solutions is an important risk factor for inducing structural and functional alterations. Objective: To compare in vitro mouse fibroblast NIH-3T3 cell viability after exposition to a neutral pH dialysis solution in comparison to cells exposed to a standard solution. Methods: Experimental study to compare the effects of a conventional standard or a neutral-pH, low-glucose degradation products peritoneal dialysis solution on the viability of exposed fibroblasts in cell culture. Both solutions were tested in all the commercially available glucose concentrations. Cell viability was evaluated with tetrazolium salt colorimetric assay. Results: Fibroblast viability was significantly superior in the neutral pH solution in comparison to control, in all three glucose concentrations (Optical density in nm-means ± SD: 1.5% 0.295 ± 0.047 vs. 0.372 ± 0.042, p < 0.001; 2.3% 0.270 ± 0.036 vs. 0.337 ± 0.051, p < 0.001; 4.25% 0.284 ± 0.037 vs. 0.332 ± 0.032, p < 0.001; control vs. neutral pH respectively, Student t Test). There was no significant difference in cell viability between the three concentrations of glucose when standard solution was used (ANOVA p = 0.218), although cell viability was higher after exposition to neutral pH peritoneal dialysis fluid at 1.5% in comparison to 2.3 and 4.25% glucose concentrations (ANOVA p = 0.008: Bonferroni 1.5% vs. 2.3% p = 0.033, 1.5% vs. 4.25% p = 0.014, 2.3% vs. 4.25% p = 1.00). Conclusion: Cell viability was better in neutral pH dialysis solution, especially in the lower glucose concentration. A more physiological pH and lower glucose degradation products may be responsible for such results. .

Introdução: A exposição contínua da membrana peritoneal a soluções convencionais de diálise é um importante fator de risco para induzir alterações estruturais e funcionais. Objetivo: Comparar a viabilidade in vitro dos fibroblastos NIH-3T3 de camundongo após exposição à solução de diálise com pH neutro com células expostas à solução padrão. Métodos: Estudo experimental; ambas as soluções foram testadas em todas as concentrações de glicose comercialmente disponíveis. A viabilidade celular foi avaliada por ensaio colorimétrico de sal tetrazólio. Resultados: A viabilidade de fibroblastos foi melhor na solução de pH neutro em relação ao controle nas três concentrações de glicose (densidade óptica em nm-médias ± DP: 1,5% 0,295 ± 0,047 vs. 0,372 ± 0,042, p < 0,001; 2,3% 0,270 ± 0,036 vs. 0,337 ± 0,051, p < 0,001; 4,25% 0,284 ± 0,037 vs. 0,332 ± 0,032, p < 0,001; controle vs. pH neutro respectivamente, teste t de Student). Não houve diferença significativa na viabilidade celular entre as três concentrações de glicose quando solução padrão foi utilizada (ANOVA p = 0,218), embora a viabilidade celular tenha sido superior após exposição aos fluidos de diálise peritoneal neutros, pH 1,5% em comparação com 2,3 e 4,25% de concentrações de glicose (ANOVA p = 0,008: Bonferroni 1,5% vs. 2,3% p = 0,033, 1,5% vs. 4,25% p = 0,014, 2,3% vs. 4,25% p = 1,0). Conclusão: A viabilidade celular foi melhor em solução neutra de pH de diálise, especialmente nas menores concentrações de glicose. O pH fisiológico e com menos produtos de degradação de glicose podem ser responsáveis por estes resultados. .

Efeito de diferentes níveis de glicose no dialisato sobre o risco de hipoglicemia durante hemodiálise em pacientes diabéticos / Effect of different levels of glucose in the dialysate on the risk of hypoglycaemia during hemodialysis in diabetic patients

INTRODUÇÃO: Hipoglicemia pode ocorrer durante hemodiálise em pacientes diabéticos renais crônicos quando se utiliza dialisato sem glicose. Com soluções de diálise contendo glicose a 90 mg/dL ou mais, isto pode ser prevenido, mas esses pacientes diabéticos podem apresentar glicemias intradialíticas muito elevadas. OBJETIVO: Nosso estudo testou um dialisato com taxas mais reduzidas de glicose tentando prevenir tanto hipo como hiperglicemia nesses pacientes. MÉTODOS: Vinte indivíduos diabéticos de nossa unidade de hemodiálise foram submetidos a três sessões com soluções de diálise com diferentes concentrações de glicose - 55 mg/dL (Fase 55) e 90 mg/dL (Fase 90) - e uma solução sem glicose (Fase ZERO). Glicemias foram medidas em cinco momentos durante cada sessão - antes e aos 30, 60, 150 e 240 min. Resultados inferiores a 70 mg/dL foram considerados como hipoglicemia. RESULTADOS: Três pacientes apresentaram seis episódios de hipoglicemia na Fase 55, mas nenhum paciente apresentou qualquer episódio na Fase 90. Na Fase ZERO, cinco pacientes apresentaram sete episódios. CONCLUSÃO: O dialisato com baixo teor de glicose (55 mg/dL) não preveniu episódios de hipoglicemia durante hemodiálise em pacientes diabéticos, um achado similar ao obtido quando se utilizou solução de diálise sem glicose. O uso de dialisato com glicose a 90 mg/dL não produziu glicemias intradialíticas mais elevadas do que as outras soluções de diálise.

INTRODUCTION: Hypoglycemia can occur during hemodialysis in diabetic chronic renal failure patients when using a dialysate without glucose. With dialysis solutions with glucose 90 mg/dL or more, this is preventable, but diabetic patients could present higher intradialytic glycemias. OBJECTIVE: We tested a dialytic fluid with a lower level of glucose trying to prevent both hypo and hyperglycemia in these patients. METHODS: Twenty diabetic individuals from our hemodialysis unit were submitted to 3 sessions with dialysis solutions with two different glucose concentrations - 55 mg/dL (Phase 55), and 90 mg/dL (Phase 90) - and a glucose-free one (Phase ZERO). Plasma glucose levels were measured at five moments during each session - before and at 30, 60, 90 and 240 min. Results under 70 mg/dL were considered as hypoglycemia. RESULTS: Three patients presented 6 episodes of hypoglycemia in Phase 55, but no patient presented any episode in Phase 90. In Phase ZERO, five patients presented 7 episodes. CONCLUSION: This dialysate with a low level of glucose (55 mg/dL) did not prevent hypoglycemia episodes during hemodialysis in diabetic patients, these occurrences being similar to that when using a dialysate without glucose. The use of a 90 mg/dL glucose dialysis solution did not induce higher intradialytic glycemia levels than the other dialysis solutions.

Manejo de falla hepática fulminante con MARS (diálisis hepática con albúmina) / Sudden liver failure handling with MARS (hepatic dialysis with albumin)

Clínica Las Condes tiene un activo programa de trasplante hepático. Como parte de éste nos vemos enfrentados cada vez con mayor frecuencia a manejar pacientes con insuficiencias hepáticas fulminantes(IHF). Esta condición aún mantiene elevadísimos niveles de mortalidad. Ultimamente se han desarrollado nuevos procedimientos que buscan remover las toxinas involucradas en esta condición clínica, y así permitirle al paciente ganar tiempo vital a la espera de que su hígado se recupere o bien pueda ser reemplazado por otro órgano. Como parte de ellas se desarrolló el MARS (Molecular Adsorbent Recirculating System), que consiste en someter a la sangre del paciente a una diálisis con Albúmina, para así depurar las toxinas que se acumulan en las IHF. El presente artículo pretende, a través de una experiencia clínica vivida en nuestra institución, revisar el tema de la IHF, las técnicas actualmente disponibles para su manejo y comunicar al resto del equipo médico que contamos con una valiosa herramienta para manejar a los pacientes que no sean referidos con esta grave condición.

Growth and Siderophore Production of Staphylococci in Human Peritoneal Dialysate

Although activity of iron uptake system (IUS) was thought to play an important role in staphylococcal growth in human peritoneal dialysate (HPD) solution, siderophore production, one of the well-known IUS, was not yet detected directly in HPD solution. Therefore, we tried to detect siderophore production directly in HPD solution by using a newly developed chrome azurol S (CAS) agar diffusion assay and to investigate the effect of IUS activity on bacterial growth in HPD solution. According to the susceptibility test for streptonigrin and the productivity of siderophore in the iron-deficient (ID) medium, Staphylococcus aureus ATCC 6538 strain and Staphylococcus epidermidis clinical isolate had higher IUS activity and grew better than S. aureus ATCC 25923 strain in the ID medium. These bacteria did not grow and produce siderophore in the unused chronic ambulatory peritoneal dialysis solution. However, these bacteria grew and produced siderophore in the HPD solution. Moreover, S. aureus ATCC 25923 strain with lower activity of IUS grew poorly and produced smaller amount of siderophore in HPD compared to S. aureus ATCC 6538 strain and S. epidermidis clinical isolate with higher activity of IUS like in the ID medium. To the best of our knowledge, this is the first report that sidero-phore production is directly detected in the HPD by CAS agar diffusion assay. These results indicated that activity of IUS plays an important role in bacterial growth in the HPD solution and pathogenesis of continuous ambulatory peritoneal dialysis peritonitis.

The effect of ligustrazine on peritoneal transport in peritoneal dialysis / 华中科技大学学报（医学）（英德文版）

In order to investigate the effect of ligustrazine (Lig) i.p. on peritoneal permeability in peritoneal dialysis and its side effects, creatinine was given intravenously and continuously to maintain the high plasma creatinine level. All the rabbits were divided into three groups: normal control group (group A), group B treated with 0.12% Lig and group C treated with 0.24% Lig. The peritoneal dialysis of all rabbits lasted 2 h. The plasma and dialysate levels of glucose, protein and creatinine were observed immediate, 30 min, 60 min, 90 min, 120 min after dialysis. Creastinine dialysate/plasma ratio (D/P), protein D/P ratio, glucose D/Do at different time points after dialysis and creatinine mass transfer area coefficient (MTAC) at 120 min were calculated. The structures of peritoneum were observed under optical microscope and electron microscope after continuously intraperitoneal injection of Lig for 14 days. The results showed that the 90-min and 120-min creatinine D/P ratios in the group C were higher than in the group A. The 120-min creatinine MATC in the group C was higher than in the group A. The rabbits treated with Lig did not show significant structure changes of peritoneum and signs of peritoneal irritation. It was suggested that Lig could increase mass transfer ability of peritoneum without significant side effects.

Comparison of plasma amino acid concentrations in end-stage renal disease patients on hemodialysis and peritoneal dialysis

OBJECTIVES: Recent reports have suggested that patients treated by CAPD have a relatively increased risk of death compared to patients undergoing HD, although the cause of this discrepancy is poorly understood. Protein malnutrition is an important risk factor in ESRD. Also, amino acid concentrations, for which the physiological function differs from that of protein, may be an independent risk factor in ESRD. There is no doubt concerning the prevalence of low amino acid levels in both HD and CAPD patients. But the difference in plasma amino acid levels between these two groups has not been well defined. The purpose of this study is to compare plasma amino acid levels between patients with ESRD on HD and CAPD. METHODS: A cross sectional study of overnight fasting plasma amino acid concentrations was performed on 12 CAPD and 45 HD patients with ESRD, matched by age, sex and body mass index. The levels of individual plasma amino acid and TAA, EAA, NEAA and BCAA were compared for the HD and CAPD groups. In order to measure losses during HD and CAPD, amino acid and protein concentrations were measured from 10 dialysates obtained from 10 HD patients and 12 peritoneal dialysis solutions from 12 CAPD patients. RESULTS: All of the measured amino acid concentrations were found to be lower in the CAPD group compared to the HD group. Furthermore, the levels of TAA (2017.3 +/- 781.1 vs. 903.3 +/- 316.1 mumole/L), EAA(1201.8 +/- 492.6 vs. 567.6 +/- 223.2 mumole/L), NEAA(815.5 +/- 308.6 vs. 335.7 +/- 100.2 mumole/L); and BCAA (315.0 +/- 146.0 vs. 145.2 +/- 65.0 mumole/L), were all lower in the CAPD group than in the HD group. The protein loss was 2.0 +/- 0.2 g/L in the peritoneal dialysate but was not detectable in the hemodialysates. TAA loss over a one week period was about 61.8 +/- 13.0mmole for the HD group and 38.0 +/- 13.0 mmole for the CAPD group. CONCLUSIONS: Our results show that amino acid concentrations are lower in ESRD patients on CAPD than on HD. It seems likely that protein loss in the peritoneal dialysate is a contributing factor to lowered plasma amino acid concentrations in ESRD patients on CAPD than on HD. We believe that the lowered amino acid concentrations observed in CAPD patients may worsen the clinical outcome compared to HD patients.