Peripheral BDNF Regulates Somatosensory-Sympathetic Coupling in Brachial Plexus Avulsion-Induced Neuropathic Pain / 神经科学通报·英文版

Brachial plexus avulsion (BPA) is a combined injury involving the central and peripheral nervous systems. Patients with BPA often experience severe neuropathic pain (NP) in the affected limb. NP is insensitive to the existing treatments, which makes it a challenge to researchers and clinicians. Accumulated evidence shows that a BPA-induced pain state is often accompanied by sympathetic nervous dysfunction, which suggests that the excitation state of the sympathetic nervous system is correlated with the existence of NP. However, the mechanism of how somatosensory neural crosstalk with the sympathetic nerve at the peripheral level remains unclear. In this study, through using a novel BPA C7 root avulsion mouse model, we found that the expression of BDNF and its receptor TrκB in the DRGs of the BPA mice increased, and the markers of sympathetic nervous system activity including α1 and α2 adrenergic receptors (α1-AR and α2-AR) also increased after BPA. The phenomenon of superexcitation of the sympathetic nervous system, including hypothermia and edema of the affected extremity, was also observed in BPA mice by using CatWalk gait analysis, an infrared thermometer, and an edema evaluation. Genetic knockdown of BDNF in DRGs not only reversed the mechanical allodynia but also alleviated the hypothermia and edema of the affected extremity in BPA mice. Further, intraperitoneal injection of adrenergic receptor inhibitors decreased neuronal excitability in patch clamp recording and reversed the mechanical allodynia of BPA mice. In another branch experiment, we also found the elevated expression of BDNF, TrκB, TH, α1-AR, and α2-AR in DRG tissues from BPA patients compared with normal human DRGs through western blot and immunohistochemistry. Our results revealed that peripheral BDNF is a key molecule in the regulation of somatosensory-sympathetic coupling in BPA-induced NP. This study also opens a novel analgesic target (BDNF) in the treatment of this pain with fewer complications, which has great potential for clinical transformation.

Avaliação de hipotermia na sala de recuperação pós-anestésica em pacientes submetidos a cirurgias abdominais com duração maior de duas horas / Hypothermia evaluation in post-anesthetic recovery room after abdominal surgeries longer than 2 hours

Introdução: Hipotermia não intencional é caracterizada por temperatura sanguínea central inferior a 36°C e pode estar presente em 53-85% dos adultos que chegam à Sala de Recuperação Pós-anestésica (SRPA). Objetivos: Avaliar a hipotermia na SRPA em pacientessubmetidos a cirurgias abdominais com duração maior de duas horas, no Hospital Nossa Senhora da Conceição, em Tubarão – SC. Métodos: Foi realizado um estudo transversal no qualpacientes submetidos a cirurgias abdominais com duração maior de duas horas, tiveram as temperaturas axilaresmonitoradas antes e depois da cirurgia e no momento da alta da SRPA. As variáveis utilizadas foram gênero,faixa etária, etnia, peso, altura, tipo de cirurgia, especialidade, tempo de cirurgia e tempo de permanência naSRPA. Resultados: A média de temperatura após a cirurgia foi de 34,5°C, já a média da alta da SRPA foi de35,7°C. Pacientes acima de 40 anos apresentaram uma média de 1,0°C menor em relação ao grupo com idadeinferior ao final da cirurgia. O grupo de pacientes com menos de 70 Kg obteve uma temperatura média menor após a cirurgia quando comparado ao outro grupo. Cirurgias com mais de 180 minutos e tempo na SRPA superiora 180 minutos apresentaram menor temperatura média posterior. Conclusões: A média de temperatura após a cirurgia foi classificada em hipotermia de grau leve. Característicasdo paciente como peso menor que 70Kg, idade maior de 40 anos e cirurgias prolongadas estiveram associadas a uma menor temperatura pós-operatória.

Introduction: Non intentional hypothermia is characterized by central blood temperature lower than 36ºC,and is present in 53-85% of adults upon arrival at the post-anesthetic recovery room. Objective: To analyze hypothermia in the post-anestheticroom, in patients submitted to abdominal surgery with duration of over two hours, in the Nossa Senhora da Conceição Hospital, in Tubarão – SC. Methods: A cross sectional study was realized.Patients submitted to abdominal surgeries with over two hours of duration, had their axillaries temperatures monitored, before and after of the surgery, and at the timeof discharge of the post-anesthetic recovery room. The variables used were, gender, age group, ethnicity, weight, height, type of surgery, and time spent in the post- anesthetic recovery room. Results: The average body temperature after surgery was 34.5°C while the average body temperature atthe post-anesthetic recovery room was 35.7°C. Patients over 40 years old presented an average temperature0.5°C lower when compared to the group less than this age, at the end of the surgery. The group of patientsweighting less than 70 Kg obtained a lower average temperatureafter surgery when compared to the other group. Surgeries longer than 180 minutes and patients that remainedmore than 180 minutes in the post-anesthetic recovery room presented lower average temperatures. Conclusion: The average temperature after surgery was classified as low level hypothermia. Patients characteristicssuch as weight lower than 70 Kg, age over 40 years old and prolonged surgeries were associated with lower post-operative temperature.

Transfusión masiva en pacientes politraumatizados / Massive transfusion in polytraumatized patients

Transfusin masiva (TM) es el reemplazo de la volemia total de un paciente por sangre de banco en menos de 24 hs, o la administración aguda de 1,5 veces la volemia estimada. Esto representa una emergencia con una alta mortalidad. La volemia puede ser reemplazada con soluciones cristaloides o coloides, pero pérdidas mayores al 40 por ciento del volumen sanguíneo total requieren transfundir glóbulos rojos, proteínas y factores de la coagulación. La coagulopatía dilucional puede presentarse luego de una aparentemente correcta reposición hídrica. La capacidad de transporte de O2 está supeditada a niveles adecuados de hemoglobina, pero no necesariamente de un valor dado, sino de las manifestaciones clínicas de la necesidad de transfundir (según tensión arterial, frecuencia cardíaca, presión venosa central, presión Wedge, etc.) La coagulopatía dilucional se manifiesta por sangrado microvascular de las mucosas, heridas y sitios de punción, o petequiado generalizado, complicándose en un 30 por ciento de los pacientes con una coagulación intravascular diseminada, por hipoperfusión y/o liberación de trombolastina tisular durante la cirugía. La hipotermia prolonga los tiempos de coagulación y enlentece las reacciones enzimáticas de las vías intrínseca y extrínseca de la coagulación. En presencia de sangrado, un tiempo de protrombina mayor 1,5 veces al normal justifica administrar plasma fresco o congelado. Un recuento menor de 50.000/mmü aconseja la transfusión de plaquetas (1 U/10 kg de peso). El tratamiento de la CID es el de la causa que la generó, y la terapéutica sustitutiva con PFC y crioprecipitados. El citrato de cada unidad de sangre transfundida se une al calcio iónico, produciendo depresión miocárdica. Sin embargo, hoy en día no se recomienda su uso de rutina, excepto que exista compromiso de la función hepática. La transfusión de sangre almacenada puede dar hiperkalemia transitoria luego de una TM, pero con repercusión sistémica importante. Asimismo los glóbulos rojos producen ácido láctico, que junto con el ácido cítrico del anticoagulante dan una carga ácida de 30-40 mmol/L, los que al degradarse dan bicarbonato, que puede producir una alcalosis postransfusional. El desarrollo del síndrome de dificultad respiratoria del adulto (SDRA) luego de una TM se debería a la formación de microagregados de plaquetas, fibrina y granulocitos...