Papel de la hemodiálisis extendida en COVID-19: a propósito de un caso / Role of expanded hemodialysis in COVID-19: a case report

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Experiencia de hemodiálisis con dializador de mediano poro en la nefropatía por cilindros del mieloma / Experience of using hemodialysis with medium cut-off dialyzer in cast nephropathy

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Valoración de la influencia de la superficie de la membrana y el flujo sanguíneo en dializadores de medio cut-off / Evaluation of the influence of the surface membrane and blood flow in medium «cut-off» (MCO) dialyzers

INTRODUCCIÓN: Recientemente, se ha incorporado a nuestras posibilidades terapéuticas una nueva clase de dializadores, las membranas de medio cut-off (MCO), diseñadas para mejorar la permeabilidad y que podrían alcanzar una eficacia similar a la hemodiafiltración. Para aumentar el conocimiento sobre su uso, el objetivo del estudio fue valorar en las membranas de MCO el efecto de la superficie y del flujo sanguíneo (Qb) sobre la eficacia depurativa. MATERIAL Y MÉTODOS: Se incluyó a 19 pacientes en programa de hemodiálisis. Cada paciente recibió 6 sesiones, en las que se varió la superficie de membrana, de 1,7 o 2,0 m2, y el Qb (300, 350, 400 o 450 mL/min). En cada sesión se determinaron diferentes solutos al inicio y al final de la diálisis. RESULTADOS: El cambio de superficie del dializador no mostró diferencias significativas en la depuración de pequeñas o grandes moléculas, sin cambios en la pérdida de albúmina. El aumento del Qb se acompañó de un aumento de depuración de pequeñas moléculas, sin mostrar diferencias en el porcentaje de reducción de β2-microglobulina, mioglobina, prolactina, α1-microglobulina y α1-glicoproteína ácida, a excepción de alguna comparación con Qb 450mL/min. Tampoco se observaron diferencias en la pérdida de albúmina en el líquido de diálisis, inferior a 2,5 g en todas las situaciones. CONCLUSIÓN: El incremento de la superficie de 1,7 a 2,0 m2 en el dializador de MCO no ha significado una mayor eficacia depurativa. En estos dializadores el aumento del Qb no parece ser tan determinante como en la hemodiafiltración, a excepción de la depuración de pequeñas moléculas

INTRODUCTION: Recently, a new class of dialyzers, medium cut-off membranes (MCO), designed to improve the permeability, which could provide an efficacy similar to hemodiafiltration, have been incorporated into our therapeutic possibilities. To increase the knowledge about its use, the objective of the study was to evaluate the effect of the surface and blood flow (Qb) on the depurative efficacy in the MCO membranes. MATERIAL AND METHODS: We included 19 patients in the hemodialysis. Each patient received 6 sessions, in which the membrane surface was varied, from 1.7 to 2.0 m2, and/or the Qb (300, 350, 400 or 450 mL/min). In each session, different solutes were determined at the beginning and end of dialysis. RESULTS: The surface change of the dialyzer did not show significant differences in the removal of small or large molecules, without changes in albumin loss. The increase in Qb was accompanied by an increase in clearance of small molecules, without showing differences in the percentage reduction of β2-microglobulin, myoglobin, prolactin, α1-microglobulin and α1-acid glycoprotein, except for some comparison with Qb 450 mL/min. There were also no differences in the loss of albumin in the dialysis fluid, less than 2.5 g in all situations. CONCLUSION: The increase of the surface area from 1.7 to 2.0 m2 in the MCO dialyzer has not meant a greater depurative effectiveness. In these dialyzers the increase of Qb does not seem to be as determinant as in hemodiafiltration except for the clearance of small molecules

Hipersensibilidad a membranas sintéticas de hemodiálisis, ¿un problema emergente? / Hypersensitivity reactions to synthetic haemodialysis membranes ¿an emerging issue?

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Hipersensibilidad a membranas sintéticas de hemodiálisis / Hypersensitivity to Synthetic Hemodialysis Membranes

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Polyurethane and PTFE membranes for guided bone regeneration: Histopathological and ultrastructural evaluation

AbstractObjective: The purpose of this study was to research a membrane material for use in guided bone regeneration.Study design: In this study, 25 male Wistar rats were used to analyze the biocompatibility and degradation processof biomembranes. The morphological changes in subcutaneous implantations were assessed after 7, 14, 21, 28 and70 days. The materials were made of polyurethane polymer (AUG) obtained from vegetal oil (Ricinus communis)and polytetrafluoroethylene membrane (PTFE). The surface characteristics of the physical barriers in scanningelectronic microscopic (SEM) were also evaluated. Results: In both groups, the initial histological analysis showedmoderate inflammatory infiltrate, which was predominantly polymorphonuclear. There was also a presence ofedema, which was gradually replaced by granulation tissue, culminating in a fibrous capsule. In the AUG group,some multinucleated giant cells were present in the contact interface, with the space previously occupied by thematerial. However, membrane degradation was not observed during the period studied. According to the presentSEM findings, porosity was not detected in the AUG or PTFE membranes. Conclusion: The researched material isbiocompatible and the degradation process is extremely slow or may not even occur at all (AU)

Microdiálisis de alta resolución. Aspectos metodológicos y aplicación al estudio de larespuesta inflamatoria cerebral / High Resolution Microdialysis. Methodological issues and application to the study of inflammatory brain response

La técnica de microdiálisis (MD) cerebral es un instrumentoque proporciona información relevante en lamonitorización del metabolismo cerebral en pacientesneurocríticos. La MD es una técnica especialmente efectivapara la detección y análisis de pequeñas moléculas,puesto que el tamaño de los poros de la membranadializante actúa como barrera restringiendo el paso deespecies mayores, tales como proteínas u otras macromoléculas.La reciente disponibilidad de catéteres demicrodiálisis con poros de mayor calibre, denominadosde “alta resolución”, permite ampliar el rango de moléculasdetectables en el dializado. Sin embargo, existencomplicaciones técnicas relacionadas con la utilizaciónde estos catéteres para estos propósitos, por lo que estacapacidad potencial para la recuperación de proteínasnecesita ser validada antes de su aplicación como herramientapara estudios de proteómica asociados a la lesióncerebral. En esta revisión se contemplan los principiosbásicos de la microdiálisis y los diferentes factores queintervienen en los procesos de recuperación de moléculasen el dializado, tales como las características físicasde la membrana dializante, así como de las moléculasque se desea investigar (AU)

Cerebral microdialysis is a tool that provides veryrelevant information in the metabolic monitoring ofbrain injured patients. It is a particularly effective technique for the detection and analysis of small molecules,given that the pores of the dialysis membrane actas a barrier to restrict the transport of larger species,such as proteins and other macromolecules. The recentavailability of microdialysis catheters with membranepores of larger size, termed “high resolution” catheters,would widen the spectrum of molecules detectablein the dialisate. However, there are technical complicationsrelated to the use of these catheters for suchpurposes, and therefore, this potential capacity for therecovery of proteins needs to be validated, in order tobegin its application as a tool in studies of proteomicsassociated with brain injuries. The following reviewdepicts the basic principles of microdialysis, and describessome of the issues involved in the recovery ofmolecules in the dialisate, including the physical propertiesof the dialysis membrane and of the moleculesof interest (AU)

Co-cultivo de células madre adultas mesenquimales y células de Schwann en presencia de membranas de policarbonato / Co-culture of adult mesenchymal stem cells and Schwann cells in presence of polycarbonate membranes

Objetivo: Estudiar si la diferenciación neural obtenida mediante el co-cultivo de células madre mesenquimalesadultas y células de Schwann es realmente una transdiferenciación o un fenómeno de fusión celular.Métodos: Se han realizado co-cultivos de células madremesenquimales y de células de Schwann, separados poruna membrana de policarbonato que permite el paso defactores solubles entre ambas poblaciones, pero impide elcontacto entre ambos tipos de células.Resultados: Los resultados muestran una diferenciaciónde las células madre mesenquimales hacia un fenotiponeural, en el transcurso de la semana siguiente al iniciodel co-cultivo.Conclusión: Se concluye que los factores neurotróficos liberados por las células de Schwann permiten una auténtica transdiferenciación de las células mesenquimales, excluyéndose la posibilidad de fusión entre ambas poblaciones celulares

Objective: To study if the neural differentiation obtained by means of the co-culture of adult mesenchymal stem cells and Schwann cells is a transdifferentiation or a phenomenon of cell fusion.Methods: Co-cultures of mesenchymal stem cells andSchwann cells, separated by a polycarbonate membranethat allows the step of soluble factors, but impedes contact among both cell populations, have been carried out.Results: The results show a neural differentiation of themesenchymal stem cells, in the course of the followingweek to the beginning of the co-culture.Conclusions: Soluble factors released by Schwann cellsallow an authentic neural transdifferentiation of adult mesenchymal stem cells, because this method of co-cultureexcluded the possibility of fusion among both cell populations

Efectos adversos a polisulfona durante la sesión de hemodiálisis / Adverse reactions to polisulphone membrane dialyzers during hemodialysis

Tradicionalmente las reacciones a dializadores durante la hemodiálisis se han relacionado con la sensibilización al óxido de etileno o con membranas celulósicas no biocompatibles, como el cuprofan o derivados. Sin embargo hay que tener en cuenta la posibilidad de reacciones a otras sustancias presentes durante la sesión de hemodiálisis. Las reacciones adversas a membranas biocompatibles del tipo polisulfona no son frecuentes, pero se han descrito casos de reacciones anafilactoides relacionados con ellas. Presentamos un caso que presentó varios episodios de broncoespasmo durante la diálisis con varios dializadores, todos ellos polisulfonas de diferentes fabricantes y con diferentes métodos de esterilización, en los que la única alternativa terapéutica fue la diálisis con membranas de celulosa modificada (triacetato de celulosa)

The majority of severe hypersensitivity reactions in hemodialysis (HD) patients has been due to sensitization to ethylene oxide or to non-byocompatible membrane dialyzers like cupramonium membrane. However could be the posibility of adverses reactions with others hemodialysis substances. Adverses reactions with byocompatible polysulphone membranes are not frequent, but some authors described anaphilactoid reactions related to them. An severe clinical syndrome of broncoespasm during hemodialysis with several byocompatible polysulphone membranes made by different manufacturers and with a variety of sterilization methods is presented here. The following day he was dialyzed on an celulose triacetate dialyzer and the hemodialysis treatment was uneventful. This case report demonstrates the complex nature involving a hypersensitivity reaction to HD

Regeneración ósea guiada utilizando membrana de óxido de aluminio en combinación con implantes oseointegrados / Guided bone regeneration using aluminum oxide membrane in combination with osseointegrated implants

La reabsorción ósea de los maxilares ha sido una de las mayorescomplicaciones al momento de rehabilitar a pacientes con implantes oseointegrados. El siguiente estudio evaluó la efectividad de la membrana de óxido de aluminio (alúmina), en la regeneración ósea de rebordes colapsados y alvéolos en los que se colocaron implantes. De un total de cinco pacientes seleccionados, se estudiaron siete sitios de los cuales tres correspondieron a un solo paciente. En cada sitio (alvéolo o reborde colapsado) se colocó un implante de titanio del sistema HIS y una membrana no biodegradable de óxido de aluminio (Allumina(R)), la cual fue retirada a las 14semanas. Todos los pacientes fueron sometidos al mismo procedimiento quirúrgico. La ganancia promedio en mm obtenidos en orden decreciente fue la siguiente: ANM: 1.7 mm, ANME: 1.6 mm, AND: 1.1 mm, AV: 1.0mm, AP: 0.5mm. Los resultados radiográficos ratificaron los resultados clínicosen cuanto a neoformación ósea, observándose además una favorable densidad ó se a periimplantaria. El análisis estadístico (basado en los resultados clínicos) t-student fue significativo para todos los parámetros evaluadoscon excepción de AP (AU)

Alveolar bone loss has been a very important cause ofcomplications in osseointegrated implant rehabilitation of edentulouspatients. This paper evaluates the effectiveness of aluminum oxidemembrane (Allumina) in the collapsed alveolar ridge where implantswere used. Seven sites were studied in 5 patients. In each of thesesites a HIS implant plus a non-biodegradable oxide aluminummembrane (Allumina®), was placed for 14 weeks. All patients weretreated with the same surgical protocol. The average gain (in mm)obtained in decreasing order was as follows: ANM: 1.7 mm, ANME:1.6 mm, AND: 1.1mm, AV: 1.0mm, AP: 0.5mm. The clinical resultswere radiographically verified and these showed bone neoformation,in addition to favorable peri-implant bone density. The t-Studentstatistical analysis based on the clinical results was significant forall the parameters evaluated with the exception of AP (AU)

Hemodiálisis crónica basada en la evidencia (I) / Evidence based chronic hemodialysis

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Hipotensión arterial en hemodiálisis / Low blood pressure in hemodialysis

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Reacción anafilactoide en hemodiálisis: interacción de inhibidores del enzima de conversión con membranas no PAN 69 / Anaphylactoid reaction in hemodyalisis: converting enzyme inhibitors interaction with no PAN 69 menbrane

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Comportamiento a largo plazo de la membrana reabsorbible colágeno-elastina como sustitutivo pericárdico en cirugía coronaria / Long Term behaviour of a collagen elastin reabsorbable membrane as pericardial substitute in coronary surgery

El incremento del número de reoperaciones ha contribuido a reforzar el determinante papel que juega el pericardio en cirugía cardiovascular. Tras el tratamiento quirúrgico de las enfermedades del corazón, el cierre primario del pericardio disminuye la formación de adherencias facilitando una eventual reintervención posterior. En cirugía cardiaca no siempre es posible o aconsejable restituir la continuidad pericárdica, representando la reacción fibrótico-adherencial un severo problema que incrementa notoriamente la morbilidad y mortalidad de las reintervenciones. Con el propósito de mejorar esta situación de graves consecuencias han sido utilizados múltiples y muy diversos materiales sustitutivos del pericardio sin resultados plenamente satisfactorios. Estudios experimentales han investigado los efectos de una membrana biodegradable de colágenoelastina en la preservación del corazón y en la regeneración del pericardio con resultados favorables. Presentamos el comportamiento a corto, medio y largo plazo del primer ensayo clínico con esta matriz artificial de tejido conectivo llevado a cabo en enfermos coronarios revascularizados quirúrgicamente. Resultados favorables que nos permiten avalar la seguridad y eficacia de esta membrana pericárdica y su capacidad para reconstituir un nuevo pericardio (AU)

The increase in the amount of reoperations has contributed to highlight the important role of the pericardium in cardiovascular surgery. Once heart disease has been surgically treated, the primary closure of the pericardium prevents the formation of adherences and facilitates a possible re-intervention. Restoring the pericardium continuity is not always possible or advisable due to the fibrotic-adherent reaction, which causes important difficulties and increases morbidity and mortality following reintervention. Many pericardial substitutive materials have been essayed to improve this situation and its consequences, none of them showing satisfactory results. Experimental studies have investigated the effect of a collagen-elastin biodegradable membrane in heart preservation and pericardial regeneration, which seems promising. We present here the short, medium and long term behaviour of this artificial connective tissue matrix in the first clinical trial carried out in patients who have undergone surgical revascularization. Our positive results allow us to guarantee the safety and effectiveness of this pericardial membrane and its ability to reconstitute a new pericardium (AU)

Membranas en el fracaso renal agudo / Membranes in acute renal failure

Las membranas de diálisis con las mejores propiedades biológicas deben ser biocompatibles, capaces de excluir las impurezas del baño de diálisis y tener grandes poros que permitan la eliminación de sustancias lo más parecido al riñón nativo sano, con pérdida casi nula de albúmina o moléculas de mayor tamaño. Los dializadores que mejor se ajustan a estas características son los dializadores de alto flujo o de alta permeabilidad. En la elección de la membrana de diálisis para el tratamiento del FRA se deben tener en cuenta la biocompatibilidad y la permeabilidad a pequeños solutos y a solutos de tamaño mediano-grande

When choosing the appropriate dialysis membrane in the acute setting, both biocompatibility and permeability should be considered. The parameters used when selecting a filter for acute dialysis are small solute removal, middle/large solute removal, and biocompatibility. With respect to small solute removal, membrane pore characteristics (pore size distribution and density) and surface area are important membrane-related determinants. Membrane characteristics define biocompatibility, although other factors, such as disinfectants may influence. Unlike in chronic hemodialysis, in which leukopenia and complement activation are well-accepted indicators of poor biocompatibility (i.e. bioincompatibility), the markers of inflammation in critically ill patients with acute renal failure are less clearly defined. In critical patients with acute renal failure activation of several inflammatory pathways preclude clear evaluation of the independent contribution of membrane biocompatibility. However, it has been demonstrated that in patients with acute renal failure, the use of cuprophan membranes can lead to complement activation and lipoxygenase stimulation. Despite initial studies demonstrated lower mortality with the use of biocompatible membranes in acute renal failure, subsequent studies casted doubts on these earlier findings. Most studies were undepowered and had randomization problems. Current evidence does not allow to recommend the unrestricted use of biocompatible membranes. However, bioincompatible membranes (grade B) and unsubstituted cellulose membranes (grade A) should be avoided. With respect to permeability, each membrane has intrinsic permeability characteristic that allow their classification according to their water and solute permeability. With respect to water permeability, membranes are classified according the ultrafiltration coefficient (CUF) expressed as mL/h/mmHg (ultrafiltered mL per hour per each mmHg of transmembrane pressure). Low permeability membranes are those with a CUF lower than 12 mL/h/mm Hg and high permeability membranes those with a CUF higher than 20 mL/h/mm Hg. With respect to solute permeability, membranes should resemble the native kidney, with a cut-off for albumin. Solute permeability is expressed by the sieving coefficient. Currently, it is not possible to recommend permeability characteristics for dislyzer membranes in the treatment of acute renal failure. However, it is plausible to recommend medium-high permeability membranes (grade C). The decision will be influenced by the dialysis modality in each particular patient

Hemodiálisis intermitente: dosis de diálisis / Dialysis dose in acute renal failure

Los factores más importantes que hay que tener en cuenta en las indicaciones del tratamiento sustitutivo renal en el FRA (ya sea diálisis intermitente o terapias continuas) son el momento de iniciar la terapia, la elección de la modalidad, elección de la membrana de diálisis y la prescripción y administración

In patients with end stage renal disease, the overall solute elimination is defined by the product of clearance and time (Kt), which is usually normalized for the volume of distribution (V) of the solute as «Kt/V.» While this parameter has demonstrated utility in defining a delivered dialysis dose in that population, no prospective studies have attempted to quantify the delivered dialysis dose in patients with ARF. For stable patients with ESRD, a dose response relationship has been shown for delivered clearance versus outcome. Several studies have demonstrated a relationship between dialysis dose and survival in acute renal failure. Although most studies have been uncontrolled, the best evidence until now comes from a randomized study that compared two dialysis schedules based on the frequency of dialysis (daily vs every other day), with the greatest survival bein associated with on most intensive dialysis. These evidences suggest that there is a threshold of dialysis dose below which mortality probaby increases. Although consensus does not exist, based on evidence from ESRD, a minimum Kt/V of 1.2 thrice weekly should be delivered to patients with ARF (Grade A). No recommendations can be made for specific dialysis dosing for patient with specific diseases at this time. This recommendation should be taken with caution, since the premises of using urea as a marker for dose calculation, i.e. stable production, volume of distribution, are not met in patients with acute renal failure. In any case, there are evidences that the delivered dose of dialysis is often lower that the prescribed one in patients with acute renal failure. As in each hemodialysis session, a number of factors can influence treatment efficacy, several systems have been developed in order to quantify dialysis dose in each session in a real time fashion. In this sense, some dialysis machines have incorporated biosensors that non invasively measure the effective ionic dialysance which is equivalent to urea clearance (K), and therefore, allows the calculation of dialysis dose as Kt. Because the normalization by the volume distribution of urea is not applicable in acute patients, Kt has been proposed as reliable marker of dialysis dose. The current recommendation is that the minimum Kt would be 40-45 liters for women and 45-50 liters for men. We would recommend that the administered dialysis dose be monitored in each dialysis session (grade C). With respect to dialysis frequency, the dose calculations referred above are based on a thrice weekly schedule, and therefore, not applicable when dialysis frequency changes. There are several ways to quantify dialysis dose when treatment frequency changes: 1. Equivalent urea clearance: EKR (ml/min) = G/TAC, G being urea generation and TAC the time-averaged urea concentration, 2. standard Kt/V (Kt/Vstd): Kt/Vstd = (G/Cm) * t/V, Cm being the mean predialysis peak urea concentrations, and 3. weekly urea reduction ratio: weekly PRU = number of sessions * [100 * (C1-C2)/C1]. The recommendation od minimum dialysis dose would be a EKR of 13 ml/min, a standard Kt/V of 2 and a weekly PRU of 210% (grade C)

Problemas de coagulación de los circuitos extracorpóreos y estrategias para mejorar la duración de los filtros / Coagulation problems in extracorporeal circuits and strategies for improving filters duration

La coagulación de los filtros en técnicas de depuración extracorpórea continuas constituye uno de los principales problemas de su aplicación. Casi la mitad de los circuitos no llegan a cumplir el tiempo programado para su recambio. No existe consenso sobre lo que debe durar dicho circuito, aunque la mayoría de fabricantes recomiendan cambiar filtro y líneas cada 48 a 72 horas. Existen una serie de medidas encaminadas a mejorar la duración. La reposición prefiltro y el control de la fracción de filtración (mantenida por debajo del 20 ó 25%) son las más eficaces y las que mejor podemos controlar. Las emboladas con suero no han demostrado aumento en la eficacia. El correcto diseño de los circuitos y, lo que está más a nuestro alcance, un buen catéter proporcionan mayor duración y menos interrupciones de tratamiento. En la mayoría de los casos debemos optar por anticoagular el circuito, procurando que nuestra actuación tenga el menor efecto sistémico sobre el paciente y reduciendo al mínimo las complicaciones hemorrágicas. En algunas circunstancias se puede optar por no anticoagular, especialmente en casos de sangrado importante, coagulopatía, trombopenia severa o alteraciones en las pruebas de la coagulación; en este caso convendrá mantener a la baja la fracción de filtración y reponer prefiltro (en predilución). Sin embargo, en la mayor parte de las ocasiones emplearemos heparina no fraccionada a dosis bajas (5- 10 U/kg·h) controlando el APTT para obtener valores de entre 1 y 1,4 veces el control (menor de 45 segundos). En casos de TIH podremos utilizar antioagulación regional con citratos, prostaglandinas (sobre todo epoprostenol), fondaparinux o inhibidotes de la trombina. En casos de coagulación frecuente de filtros se pueden asociar prostaglandinas a heparina. El esquema de actuación queda resumido en el algoritmo de la figura 1. Los niveles de evidencia se describen en la tabla I

Filter coagulation is the cause of replacing kits in 40% to 70% of the cases. Furthermore, circuit coagulation represents loss of blood (around 200 mL), nursing workload, consumption of fungibles and temporary interruption of treatments. Anticoagulation of the extracorporeal circuit is generally required to prevent clotting of the circuit and preserve filter performance. On the other hand, anticoagulants can produce systemic effects and bleeding. Thus, there is a struggle between filter coagulation and hemorrhage. Circuit survival time is generally used to judge the effect of anticoagulation. Unfractionated sodium heparin (standard heparin) remains the most frequently used agent and the drug of choice for patients who require anticoagulation. It is cheap, and at low dosages (5-10 IU/kg per hour) the systemic effects are minor, providing an activated thromboplastin time less than 1.5 times the control. The drugs most often used apart from heparin in CRRT are prostaglandins and citrates. In patients with filter hypercoagulability heparin is frequently insufficient, and apart from physical maneuvers, such as reinfusion in pre-dilution and the reduction of the filtration fraction, we can add prostacyclin to heparin to increase filter life. Continued exposure to heparin may lead to the development of heparin-immunoglobulin G4 complexes and heparin-induced thrombocytopenia type II (TIH II), increasing the risk of both bleeding and thrombotic complications. In these cases there are several alternatives to heparin: regional citrate anticoagulation, prostaglandins, human recombinant hirudin (lepirudin), danaparoid and argatroban

A natural biomembrane as a new proposal for the treatment of pressure ulcers

Pressure ulcer is a common syndrome of diffi cult treatment among bedridden individuals, with clinical and socioeconomic repercussions. A recently developed natural biomembrane (NBM) as a therapeutic option for leg ulcers with debriding and neo-angiogenic properties encouraged us to apply it as a treatment for pressure ulcers. The authors report the results obtained with the NBM dressing on alternate days and followed up two cases for 6 months: a 76-year-old woman with sepsis and malnutrition and a sacral ulcer (15 x 13 cm wide x 1.5 cm deep) and a 77-year-old man with sequel of a brain vascular accident and two 3 cm deep sacral ulcers of 5.6 x 6.4 cm (left) and 6.6 x 8 cm (right). NBM promoted rapid debridement, an important granulogenic stimulus and full healing within less than 6 months in both cases. Thus, the natural biomembrane showed outstanding debriding and neo-angiogenic properties in the treatment of pressure ulcers, representing an effective, practical and low cost dressing

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Tratamiento de la intoxicación aguda por litio mediante hemodiálisis con dializadores de alta eficiencia / Treatment of acute lithium intoxication wigh high-flux haemodialysis membranes

El carbonato de litio se utiliza de forma habitual para el tratamiento de los trastornosbipolares (maniaco-depresivos). Sin embargo, debido a su estrecho margenterapéutico la elevación de los niveles séricos, bien durante la terapia crónica demantenimiento o después de una sobredosis aguda, puede dar lugar a toxicidadgrave. En la intoxicación aguda severa por litio el tratamiento establecido es la hemodiálisis,que permite la eliminación rápida de la droga. Las membranas de altoflujo deben ser capaces de eliminar más litio por hora de hemodiálisis, pero existenpocas evidencias al respecto. Se presentan tres pacientes con una intoxicaciónaguda por litio con riesgo vital, complicada en dos de ellos por insuficiencia renal,que fueron tratados con éxito mediante hemodiálisis intermitente diaria con membranasde alto flujo. Las técnicas actuales de hemodiálisis, utilizando dializadoresde alta eficiencia y baño de diálisis con bicarbonato, permiten una eliminaciónexcelente del litio sin el rebote que típicamente se observaba en el pasado tras lahemodiálisis convencional. La hemodiálisis debe ser instaurada precozmente encualquier paciente con intoxicación por litio que presente coma, convulsiones, fallorespiratorio, deterioro del estado mental, y especialmente si la función renal estácomprometida

Lithium carbonate is commonly prescribed for the treatment of bipolar(manic-depressive) disorders. However, because of its narrow therapeutic indexan excessive elevation of serum lithium concentration, either during chronicmaintenance therapy or after an acute overdose, can result in serious toxicity.In addition to supportive care, the established treatment of severe lithium toxicity is haemodialysis. Conventional haemodialysis can reduce serum lithiumrapidly, but post-dialysis rebound elevations with recurrent toxicity have beendocumented in old publications. High-flux membranes should be capable ofremoving more lithium per hour of haemodialysis, but published values are notavailable. We report here three patients with acute lithium intoxication whowere treated successfully with bicarbonate and high-flux haemodialysis membranes.Our patients presented with a severe degree of intoxication, based onthe amount of drug ingested, the initial serum lithium level, the severity of neurologicsymptoms and systemic manifestations. Two patients developed acuterenal failure probably as a result of volume depletion since it was rapidly reversibleby haemodialysis and infusion therapy. In addition, consecutive haemodialysissessions and improvement of renal function allowed a rapid decreasein serum lithium levels without haemodynamic instability or reboundelevations in lithium concentration. The effectiveness of the procedure in thesecases can be attributed to the use of bicarbonate dialysate and high-efficiencydialysers. This is the first report describing the effect of high-efficiency dialyserson lithium pharmacokinetic. Using this technique the elimination rate oflithium was found to be greater than previously reported with haemodialysis