Ultrafiltration Tolerance: A Phenotype That We Need to Recognize.

BACKGROUND: The evaluation and management of fluid balance are key challenges in critical care patients who require renal replacement therapies because cumulative fluid balance is an independent factor that increases morbidity and mortality in different clinical scenarios. SUMMARY: One of the strategies when fluid overload is refractory to diuretics is extracorporeal fluid removal (i.e., net ultrafiltration [UFNET] during kidney replacement therapy). However, problems with UFNET without individualized assessment are cardiovascular events and intradialytic hypotension, events that contribute to decreasing organ perfusion and sympathetic stress. Therefore, we must consider and try to predict the best timing for the start of ultrafiltration and find the point where the patient is most tolerant to ultrafiltration, making a simile to the concept of fluid tolerance. KEY MESSAGES: UFNET is a continuous and dynamic process, going through moments of tolerance and intolerance to ultrafiltration; as nephrologists, we must take the necessary measures to move through this period.

Adsorption Mass Transfer Zone of Vancomycin in Cartridges With Styrene-Divinylbenzene Sorbent.

Cartridges for hemoadsorption containing styrene-divinylbenzene sorbent are used for multiple conditions, such as intoxication. The mass transfer zone comprises the extension along the longitudinal span of the cartridge where adsorption occurs. The aim of this experiment is to evaluate the mass transfer zone for vancomycin in the HA380 cartridge. The experiment was carried out twice. A saline solution with vancomycin passed through a HA380-modified cartridge at 100 ml/min in a single-pass fashion. The cartridge had four openings along its longitudinal dimension, at 3, 6, 9, and 12 cm. In both experiments, the collection of aliquots occurred at minute 4, in the four openings and pre- and post-cartridge, and an additional sample from the effluent bag at the end of each experiment. In the second experiment, an additional sampling of the same six sites occurred at minute 14. The sigmoidal shape of the curve for the mass transfer zone of vancomycin was similar to the theoretical one. In experiment one, at minute 4, vancomycin clearance was 98.75 ml/min. In experiment two, vancomycin clearance at minutes 4 and 14 was 93.76 and 93.20 ml/min, respectively. This implies an adequate and optimal design of the HA380 cartridge.

Development of a new miniaturized system for ultrafiltration.

Acute decompensated heart failure and fluid overload are the most common causes of hospitalization in heart failure patients, and often, they contribute to disease progression. Initial treatment encompasses intravenous diuretics although there might be a percentual of patients refractory to this pharmacological approach. New technologies have been developed to perform extracorporeal ultrafiltration in fluid overloaded patients. Current equipment allows to perform ultrafiltration in most hospital and acute care settings. Extracorporeal ultrafiltration is then prescribed and conducted by specialized teams, and fluid removal is planned to restore a status of hydration close to normal. Recent clinical trials and European and North American practice guidelines suggest that ultrafiltration is indicated for patients with refractory congestion not responding to medical therapy. Close interaction between nephrologists and cardiologists may be the key to a collaborative therapeutic effort in heart failure patients. Further studies are today suggesting that wearable technologies might become available soon to treat patients in ambulatory and de-hospitalized settings. These new technologies may help to cope with the increasing demand for the care of chronic heart failure patients. Herein, we provide a state-of-the-art review on extracorporeal ultrafiltration and describe the steps in the development of a new miniaturized system for ultrafiltration, called AD1 (Artificial Diuresis).

Effect of Mechanical Vibration on Kinetics of Solute Adsorption.

INTRODUCTION: Hemadsorption with new sorbent cartridges is an emerging extracorporeal blood purification technique. Flow distribution inside the sorbent is one of the main issues concerning the device's performance and optimal sorbent utilization. In this experiment, we aimed to investigate the efficacy of vibration during adsorption by measuring the removal of vancomycin. METHODS: In this experimental study, 1,000 mL of saline with 10 g of vancomycin was circulated in a closed circuit (set flow of 250 mL/min) simulating a hemadsorption blood run using HA380 minimodule cartridge containing 75 g of wet resin. This vibration model was implemented with a damping head device installed in front of the adsorption cartridge during the experiment. The kinetics of the vancomycin were assessed by removal ratio over 120 min. RESULTS: We found no difference between the two models. Adsorption with and without vibration did not differ significantly for partial reduction ratios, overall amount of adsorbed molecule, or adsorption kinetics. CONCLUSION: The current design and structure of the minimodule cartridge demonstrated no difference in small-middle solute removal. Further improvement with the addition of mechanical vibration to the device was not observed.

The role of peritoneal dialysis in the treatment of acute kidney injury in neurocritical patients: a retrospective Brazilian study.

BACKGROUND: Acute kidney injury (AKI) occurs frequently in the neurocritical intensive care unit and is associated with greater morbidity and mortality. AKI and its treatment, including acute kidney replacement therapy, can expose patients to a secondary greater brain injury. This study aimed to explore the role of peritoneal dialysis (PD) in neurocritical AKI patients in relation to metabolic and fluid control, complications related to PD and outcome. METHODS: Neurocritical AKI patients were treated by PD (prescribed Kt/V = 0.40/session) using a flexible catheter and a cycler and lactate as a buffer. RESULTS: A total of 58 patients were included. The mean age was 61.8 ± 13.2 years, 65.5% were in the intensive care unit, 68.5% needed intravenous inotropic agents, 72.4% were on mechanical ventilation, APACHE II was 16 ± 6.67 and the main neurological diagnoses were stroke (25.9%) and intracerebral haemorrhage (31%). Ischaemic acute tubular necrosis (iATN) was the most common cause of AKI (51.7%), followed by nephrotoxic ATN AKI (25.8%). The main dialysis indications were uraemia and hypervolemia. Blood urea and creatinine levels stabilised after four sessions at around 48 ± 11 mg/dL and 2.9 ± 0.4 mg/dL, respectively. Negative fluid balance and ultrafiltration increased progressively and stabilised around 2.1 ± 0.4 L /day. Weekly delivered Kt/V was 2.6 ± 0.31. The median number of high-volume PD sessions was 6 (4-10). Peritonitis and mechanical complications were not frequent (8.6% and 10.3%, respectively). Mortality rate was 58.6%. Logistic regression identified as factors associated with death in neurocritical AKI patients: age (odds ratio (OR) = 1.14, 95% confidence interval (CI) = 1.09-2.16, p = 0.001), nephrotoxic AKI (OR = 0.78, 95% CI = 0.69- 0.95, p = 0.03), mechanical ventilation (OR = 1.54, 95% CI = 1.17-2.46, p = 0.01), intracerebral haemorrhage as main neurological diagnoses (OR = 1.15, 95% CI = 1.09-2.11, p = 0.03) and negative fluid balance after two PD sessions (OR = 0.94, 95% CI = 0.74-0.97, p = 0.009). CONCLUSION: Our study suggests that careful prescription may contribute to providing adequate treatment for most neurocritical AKI patients without contraindications for PD use, allowing adequate metabolic and fluid control, with no increase in the number of infectious, mechanical and metabolic complications. Mechanical ventilation, positive fluid balance and intracerebral haemorrhage were factors associated with mortality, while patients with nephrotoxic AKI had lower odds of mortality compared to those with septic and ischaemic AKI. Further studies are needed to investigate better the role of PD in neurocritical patients with AKI.

Sorbent functionalization with vancomycin enhances bacteria killing in extracorporeal hemoadsorption.

BACKGROUND: The level of bacteremia in patients with sepsis and septic shock is a predictor of complications and mortality, regardless of the type of bacteria. Devices for bacteria, endotoxin and cytokines removal by adsorption have been recently developed. Thus, extracorporeal blood purification therapies have been proposed as adjunctive therapy in sepsis in combination with drugs. Some potentially useful drugs, however, are precluded due to their organ or metabolic toxicity. The present study represents a preliminary report on the in vitro effect of a sorbent device (minimodule with HA380 beads, Jafron medical, Zhuhai, China) in which the particles have been functionalized with vancomycin on the surface. The impact of the surface-modified beads on circulating bacteria (Staphylococcus aureus) has been tested in a simulated in vitro circulation. METHODS: In vitro experiments were carried out with 800 mL of blood enriched with S. aureus species. Blood was circulated in the vancomycin-functionalized and non-functionalized mini-module cartridges in hemoadsorption setup (300 mL each) and the bactericidal effect was assessed. Also, 200 mL of blood was used as a control. RESULTS: A significant increase in the time to positivity of blood cultures was observed after 60 min and also after 120 min of therapy with the mini-module functionalized with vancomycin as opposed to the non-functionalized cartridge. CONCLUSIONS: These results suggest a possible way of treating sepsis by using drug- or antibiotic-functionalized cartridges without worrying about pharmacological toxicity. The prolongation of the time to bacterial culture positivity to S. aureus after a passage through a column packed with beads functionalized with vancomycin represents a proof of concept.

Caracterización clínica y microbiológica de los eventos de peritonitis asociada a diálisis peritoneal en un hospital de Chile. Un análisis retrospectivo / Clinical and microbiological characterization of Peritoneal Dialysis-Associated Peritonitis events in a hospital in Chile. A retrospective analysis

INTRODUCCIÓN: Las infecciones asociadas a diálisis peritoneal constituyen una de las causas de morbimortalidad más importante en estos pacientes y la terapia antimicrobiana empírica y dirigida adecuada es fundamental para mejorar el resultado, por lo que es importante establecer la microbiología local. OBJETIVO: Revisar la experiencia clínica de cinco años del Hospital Carlos Van Buren de Valparaíso, Chile, describiendo las características clínicas y microbiológicas de los pacientes con episodios de peritonitis asociada a diálisis peritoneal. METODOLOGÍA De forma retrospectiva se accedió a los registros clínicos de aquellos pacientes mayores de 18 años que presentaron al menos un evento de peritonitis asociada a diálisis peritoneal. RESULTADOS: De un total de 26 episodios, 62% de los pacientes fueron de sexo femenino, con un promedio de edad de 53 años. La principal comorbilidad fue la hipertensión arterial (100%), y el dolor abdominal fue el síntoma más frecuente (85%), con una mortalidad general de 7,7%. En el laboratorio la leucocitosis, la proteína C reactiva (PCR) y la velocidad de hemosedimentación (VHS) fueron los hallazgos más importantes. Predominaron las cocáceas grampositivas (54%), seguido de bacilos gramnegativos no fermentadores y Enterobacterales en igual proporción (11,5% cada grupo). Casos aislados de Candida albicans y Pasteurella canis fueron identificados, y en 15% de los casos el cultivo resultó negativo. CONCLUSIÓN: Se pudo conocer las características clínicas y microbiológicas locales de esta patología, para así redefinir las directrices de manejo en la institución.

BACKGROUND: Infections associated with peritoneal dialysis are one of the most important causes of morbidity and mortality in these patients, and adequate empirical and targeted antimicrobial therapy are essential to improve the outcome, so it is important to establish the local microbiology. AIM: To review the clinical experience of 5 years at the Carlos Van Buren Hospital in Valparaíso, Chile, in order to know the clinical and microbiological characteristics of patients with episodes of peritonitis associated with peritoneal dialysis. METHODS: Retrospectively, the clinical records of those patients over 18 years of age who presented at least one peritonitis event associated with peritoneal dialysis were accessed. RESULTS: Of a total of 26 episodes, 62% of the patients were female, with a mean age of 53 years. The main comorbidity was arterial hypertension (100%), and abdominal pain was the most frequent symptom (85%), with an overall mortality of 7.7%. In the laboratory parameters, leukocytosis, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were the most important findings. Gram-positive cocci (54%) predominated, followed by Gram-negative non-fermenting and enterobacterial bacilli in the same proportion (11.5% each group). Isolated cases of Candida albicans and Pasteurella canis were identified, and in 15% of the cases the culture was negative. CONCLUSION: It was possible to know the local clinical and microbiological characteristics of this pathology, in order to redefine management guidelines for our institution.

Diálisis de albúmina de paso único (SPAD) como soporte hepático extracorpóreo en paciente COVID-19 crítico. Caso clínico / Single-pass albumin dialysis as treatment of acute on chronic liver failure during COVID-19 pneumonia. report of one case

Liver transplantation is the only effective therapy to reduce the high mortality associated with acute liver failure and acute on chronic liver failure (ACLF). Single-pass albumin dialysis (SPAD) is an extracorporeal supportive therapy used as a bridge to liver transplantation or regeneration. We report a 44-year-old man with alcoholic cirrhosis admitted for critical COVID-19 pneumonia that evolves with ACLF. SPAD technique was performed completing six sessions, with a reduction of bilirubin and ammonia levels. He evolved with severe respiratory failure and refractory septic shock, dying. SPAD is a safe and efficient technique aimed to eliminate liver toxins, preventing multiorgan damage interrupting the process known as the "autointoxication hypothesis". It is easy to implement in any critical patient unit and has lower costs than other extracorporeal liver support therapies.

Intercambio plasmático terapéutico por plasmafiltración: experiencia de 11 años de un centro / Therapeutic plasma exchange: experience in 102 patients

BACKGROUND: Therapeutic Plasma Exchange (TPE) is a procedure in which plasma and harmful macromolecules are separated from the rest of the blood components by centrifugation or filtration through membranes and are replaced with solutions with albumin and/or plasma. AIM: To communicate our experience using TPE by filtration. MATERIAL AND METHODS: Review of records of 655 TPE sessions performed in 102 patients aged 50 ± 18 years (64% women). The requirement of renal replacement therapy (RRT) and seven days and one year mortality were recorded. RESULTS: Forty five percent of patients had hypertension or diabetes. The main indications for TPE were pulmonary-renal syndrome (PRS) (62%) and antibody mediated graft rejection (29%), followed by neurological diseases (36%). Fifteen percent of patients required RRT for one year. Mortality at seven days and one year was 20 and 30%, respectively. Out of the total of deaths associated with kidney diseases, 88% corresponded to PRS and ANCA vasculitis. The main complications were thrombocytopenia in 41%, hypocalcemia in 18%, and hypotension in 16%. CONCLUSIONS: In our experience, TPE by filtration is a safe technique, with mild and preventable complications. Despite this, the reported mortality is high, which reflects the severity of the diseases that motivated the indication for TPE.

COVID-19, shock séptico refractario y terapia extracorpórea de purificación sanguínea con OXIRIS® / Management of refractory septic shock with blood purification therapy using a special filter: report of one case

Sepsis is one of the leading causes of death in critically ill patients with COVID-19 and blood purification therapies have a role to immunomodulate the excessive inflammatory response and improve clinical results. One of the devices designed for these therapies is the oXiris® filter, allowing to perform renal replacement therapy combined with selective adsorption of endotoxins and cytokines. We report a 55-year-old male with COVID who developed a septic shock secondary to a sepsis caused by Pseudomona aeruginosa, refractory to the usual management. A veno-venous continuous hemofiltration was started using the oXiris® filter for 48 hours. Subsequently, there was an improvement in clinical perfusion parameters and a reduction in inflammatory markers. The patient was discharged from the intensive care one month later.

Necrosis papilar renal bilateral de resolución espontánea como causa de hematuria microscópica. Caso clínico / Bilateral renal papillary necrosis of spontaneous resolution as a cause of microscopic hematuria. Report of one case

Renal papillary necrosis is an infrequent cause of hematuria characterized by ischemic necrosis of the renal medulla, especially the papilla. Its most common cause is analgesic abuse. Despite being oligo-symptomatic, in many cases its presence is associated with serious functional sequelae. Imaging, especially computed tomography, is essential to make the diagnosis. We report a 63-year-old female studied for an asymptomatic microscopic hematuria whose tomographic study showed a bilateral renal papillary necrosis. No etiology was found, and she evolved with a spontaneous complete remission.