Sobredosis accidental de enoxaparina en un recién nacido / Enoxaparin overdose in a newborn

La enoxaparina es una heparina de bajo peso molecular utilizada en el período neonatal. Requiere menor monitoreo que la heparina estándar o no fraccionada, si bien es escaso el conocimiento actual acerca de su dosis y de los niveles terapéuticos en los neonatos. Además, existe una información muy limitada respecto del manejo de su sobredosificación en este grupo de edad. Se presenta el primer caso publicado en castellano de un neonato que recibió una dosis de enoxaparina diez veces superior a la terapéutica de forma accidental y en el que se administró una dosis aislada de protamina para revertir su efecto.

Enoxaparin is a low molecular weight heparin used in the neonatal period. It requires less monitoring than standard or unfractionated heparin, although current knowledge about its dose and therapeutic levels in neonates is scarce. In addition, there is very limited information about the management of overdose in this age group. We present the first case published in Spanish of a neonate who accidentally received a dose of enoxaparin ten times higher than the therapeutic one and an isolated dose of protamine to reverse its effect.

Methylene blue to treat protamine-induced anaphylaxis reactions. An experimental study in pigs

ABSTRACT Objective: To examine if methylene blue (MB) can counteract or prevent protamine (P) cardiovascular effects. Methods: The protocol included five heparinized pig groups: Group Sham -without any drug; Group MB - MB 3 mg/kg infusion; Group P - protamine; Group P/MB - MB after protamine; Group MB/P - MB before protamine. Nitric oxide levels were obtained by the nitric oxide/ozone chemiluminescence method, performed using the Nitric Oxide Analizer 280i (Sievers, Boulder, CO, USA). Malondialdehyde plasma levels were estimated using the thiobarbiturate technique. Results: 1) Groups Sham and MB presented unchanged parameters; 2) Group P - a) Intravenous protamine infusion caused mean arterial pressure decrease and recovery trend after 25-30 minutes, b) Cardiac output decreased and remained stable until the end of protamine injection, and c) Sustained systemic vascular resistance increased until the end of protamine injection; 3) Methylene blue infusion after protamine (Group P/MB) - a) Marked mean arterial pressure decreased after protamine, but recovery after methylene blue injection, b) Cardiac output decreased after protamine infusion, recovering after methylene blue infusion, and c) Sustained systemic vascular resistance increased after protamine infusion and methylene blue injections; 4) Methylene blue infusion before protamine (Group MB/P) - a) Mean arterial pressure decrease was less severe with rapid recovery, b) After methylene blue, there was a progressive cardiac output increase up to protamine injection, when cardiac output decreased, and c) Sustained systemic vascular resistance decreased after protamine, followed by immediate Sustained systemic vascular resistance increase; 5) Plasma nitrite/nitrate and malondialdehyde values did not differ among the experimental groups. Conclusion: Reviewing these experimental results and our clinical experience, we suggest methylene blue safely prevents and treats hemodynamic protamine complications, from the endothelium function point of view.

Recanalization after acute deep vein thrombosis / Recanalizacao apos trombose venosa profunda aguda

The process of recanalization of the veins of the lower limbs after an episode of acute deep venous thrombosis is part of the natural evolution of the remodeling of the venous thrombus in patients on anticoagulation with heparin and vitamin K inhibitors. This remodeling involves the complex process of adhesion of thrombus to the wall of the vein, the inflammatory response of the vessel wall leading to organization and subsequent contraction of the thrombus, neovascularization and spontaneous lysis of areas within the thrombus. The occurrence of spontaneous arterial flow in recanalized thrombosed veins has been described as secondary to neovascularization and is characterized by the development of flow patterns characteristic of arteriovenous fistulae that can be identified by color duplex scanning. In this review, we discuss some controversial aspects of the natural history of deep vein thrombosis to provide a better understanding of its course and its impact on venous disease.

O processo de recanalização das veias dos membros inferiores, após um episódio de trombose venosa profunda aguda em pacientes anticoagulados com heparina e inibidores da vitamina K, faz parte da evolução natural da remodelagem do trombo venoso. Esse complexo processo de remodelagem envolve a adesão do trombo à parede da veia, à resposta inflamatória da parede do vaso, levando à organização e subsequente contração do trombo, à neovascularização e à lise espontânea de áreas no interior do trombo. A presença de fluxo arterial espontâneo em veias com trombose recanalizada tem sido descrita como secundária à neovascularização e se caracteriza pelo desenvolvimento de fluxo com padrão de fístulas arteriovenosas, identificadas por meio de mapeamento dúplex colorido. Nesta revisão, são discutidos alguns aspectos controversos da história natural da trombose venosa profunda, para uma melhor compreensão da sua evolução e do seu impacto sobre a doença venosa.

Reversión de la anticoagulación en pacientes con dosis altas de heparina: protamina en dosis standard versus dosis reducidas / Reversal anticoagulation in patients with high doses heparin: protamine in standard doses versus small doses

Evaluar y comparar, en pacientes sometidos a circulación extracorpórea (CEC), la reversión de la anticoagulación con dos dosis distintas de protamina: una dada en forma proporcional a la heparina usada versus una dosis calculada según peso del paciente, independiente de la heparina administrada. Material y Método: Se incorporaron los pacientes que para la CEC requirieron una dosis de heparina superior a 300 U•kg-1. Los criterios de exclusión fueron: alteraciones de las pruebas de coagulación preoperatorias y paro circulatorio hipotérmico. La técnica anestésica, el uso de fármacos y el uso de hemoderivados fue de decisión del anestesista. Para la reversión con protamina los pacientes fueron aleatorizados en dos grupos: Grupo A o dosis estándar: Reversión con 0,8 mg protamina por cada 100 U de heparina usada. Grupo B o dosis reducida: Reversión con 2,4 mg protamina•kg-1, independiente de la dosis de heparina usada. La protamina fue preparada por una persona ajena al pabellón y el equipo tratante era ciego al grupo del paciente. El seguimiento de los pacientes las primeras 24 h en UTI fue realizado por una persona ciega al grupo del paciente. Resultados: Hubo solamente una diferencia demográfica: más mujeres en el grupo B (p = 0,029). En el preoperatorio no hubo diferencias en hematocrito, recuento de plaquetas, tratamiento anticoagulante oral (TACO) y heparina preoperatoria, tipo de cirugía y uso de aspirina. En el intraoperatoriono hubo diferencias en el tiempo de coagulación activada (TCA) basal, hematocritos en CEC, TCA en CEC y duración de CEC. La dosis de heparina por kg de peso fue mayor en el grupo B (p = 0,0433). La relación protamina/heparina total fue 0,81 para el Grupo A y 0,44 para el Grupo B, las que fueron diferentes (por el diseño del estudio)...

Objective: To evaluate and compare reversal of anticoagulation with different dose regimens of protamine in patients undergoing to CPB (cardiopulmonary bypass), one given according to the heparin dose administered and another calculated according to patient’s weight. Patients y Methods: Patients subjected to CPB and receiving a heparin dose greater than 300 IU/kg were enrolled. Exclusion criterias were: preoperative coagulopathy and hypothermic circulatory arrest. The anesthetic technic, drugs given and blood products transfusion were decided by the attending anesthesiologist. Patients were randomized to: Group A or standard dose: Reversal with 0.8 mg of protamine for each 100 IU of heparin given. Group B or reduced dose: Reversal with 2.4 mg of protamine per kilogram of patient’s weight, independent of heparin dose used. The protamine was prepared for a person blinded to group allocation, same as the team taking care of the patient. The patient’s follow up in the ICU during the first 24 hours was also done by someone blinded to group allocation. Results: There was only one demographic difference at baseline: more women in Group B (p = 0.029). There were no differences among the preoperative: hematocrit, platelets count, oral anticoagulant treatment, heparin administration, aspirin consumption and surgical plan. In the intraoperative course there were no differences in the baseline ACT, hematocrit during CBP, ACT in CBP and CBP duration. The average heparin dose (adjusted per kilogram) was greater in Group B (p = 0.0433).The protamine/heparin ratios were different among groups (Group A 0.81; Group B 0.44), as expected in this study design. The activated coagulation time (ACT)...

Guías para la prevención de enfermedad tromboembólica en pacientes pediátricos: (IV Consenso Venezolano sobre Enfermedad Tromboembólica 2008-2009): [revisión] / Guidelines for the prevention of thromboembolic disease in pediatric patients (IV Consensus on thromboembolic disease Venezuelan 2008-2009): [review]

La Enfermedad Tromboembólica (ETE) en la edad pediátrica ha adquirido mayor importancia, debido al aumento de su incidencia derivada de la optimización de técnicas diagnósticas y terapéuticas. Los episodios de ETE en los niños aparecen de forma brusca y el diagnóstico se hace con métodos incruentos como ecografía doppler, resonancia magnética y estudios angiográficos. Hasta hace poco no se disponía de recomendaciones específicas para el tratamiento de la ETE en el niño; en la actualidad se cuenta con esquemas terapéuticos desarrollados con base en la experiencia con adultos, adaptados a la edad pediátrica. Se revisan las principales patologías y procedimientos susceptibles de producir enfermedad tromboembólica así como las indicaciones de los principales agentes terapéuticos, incluyendo las heparinas, los anticoagulantes orales, antiagregantes y fibrinolíticos y se dan recomendaciones de uso. Dada la morbimortalidad observada en niños afectados por ETE, hay sobradas justificaciones para tomar una actitud activa que intente controlar el proceso y procurar que el beneficio esperado sea siempre superior al riesgo inherente al tratamiento.

Thromboembolic disease (TD) in pediatric patients has gained relevance, due to an increase in its incidence, as a result of the optimization of diagnostic and therapeutic techniques. Episodes of TD in children appear abruptly and diagnosis is carried out through non-invasive methods such as doppler ecography, magnetic resonance imaging and angiography. Until recently, specific recommendations for the treatment of TD in children were unavailable; nowadays, therapeutic schemes developed on the basis of experience with adults adapted to pediatric patients are available. The main pathologies and procedures capable of causing thromboembolic disease were reviewed, as well as the indications of main therapeutic agents, including heparins, oral anticoagulants, platelet antiagregant and fibrinolytic agents. Use recommendations are given. Considering the morbimortality rate observed in children affected by TD, there are plenty of reasons to take an active role to control the process, and seek that expected benefits outweigh the inherent risks of treatment.

Assessment of a DNA vaccine encoding an anchored-glycosylphosphatidylinositol tegumental antigen complexed to protamine sulphate on immunoprotection against murine schistosomiasis

Protamine sulphate/DNA complexes have been shown to protect DNA from DNase digestion in a lipid system for gene transfer. A DNA-based vaccine complexed to protamine sulphate was used to induce an immune response against Schistosoma mansoni anchored-glycosylphosphatidylinositol tegumental antigen in BALB/c mice. The protection elicited ranged from 33 to 44 percent. The spectrum of the elicited immune response induced by the vaccine formulation without protamine was characterized by a high level of IgG (IgG1> IgG2a). Protamine sulphate added to the DNA vaccine formulation retained the green fluorescent protein encoding-plasmid longer in muscle and spleen. The experiments in vivo showed that under protamine sulphate effect, the scope of protection remained unchanged, but a modulation in antibody production (IgG1= IgG2a) was observed.