RESUMO

BACKGROUND AND OBJECTIVES: To assess the potential neurotoxic effects at the ultrastructural level of magnesium sulfate administered intrathecally as a single or multi-dose. METHODS: Our study was conducted with 24 Sprague-Dawley rats that weighed 250-300 g. After a 4-hour fast, the rats were given 10 mg.kg(-1) xylazine chloride intraperitoneal and then randomly allocated into three groups. Group I (n=8) received 0.9% normal saline, Group II (n = 8) was given one intrathecal injection of 0.02 mL of 15% magnesium sulphate, and Group III (n = 8) was given 0.02 mL of 15% magnesium sulphate once a day for seven days. The injections were given within 0.40 × 50 mm from the lumbar area. After seven days, the animals were sacrificed under anesthesia with an aortic injection of 10% formaldehyde and their tissues were fixed. The medulla spinalis was then examined and histopathologically evaluated under an electron microscope. The Kruskal-Wallis test was used for statistical evaluation. A value of p < .05 was considered to be statistically significant. RESULTS: Significant neurodegeneration was detected in rats given single or repeated magnesium sulphate injections compared to the control group. The histopathological evaluation score of this group was also high. CONCLUSIONS: Based on electron microscopic examination, we found that intrathecal magnesium sulphate administration induced neurodegeneration.

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RESUMO

JUSTIFICATIVA E OBJETIVOS: Avaliar os potenciais efeitos neurotóxicos em nível ultraestrutural desulfato de magnésio administrado por via intratecal em dose única ou múltipla. MÉTODOS: Estudo realizado com 24 ratos Sprague-Dawley, peso médio entre 250 e 300 g. Apósjejum de 4 horas, os ratos receberam 10 mg.kg-1 de cloreto de xilazina por via intraperitoneale, em seguida, foram divididos aleatoriamente em três grupos. Grupo I (n = 8) recebeu 0,9% desoro fisiológico normal, Grupo II (n = 8) recebeu uma injeção de 0,02 mL de sulfato de magnésioa 15% por via intratecal e Grupo III (n = 8) recebeu 0,02 mL de sulfato de magnésio a 15% umavez por dia durante sete dias. As injeções foram aplicadas dentro de 0,40x50 milímetros daárea lombar. Após sete dias, os animais foram sacrificados sob anestesia com uma injeção deformaldeído a 10% na aorta e os tecidos foram fixados. A medula espinal foi, então, examinadae histopatologicamente avaliada sob microscópio eletrônico. O teste de Kruskal-Wallis foi usadopara avaliação estatística. Um valor de p < 0,05 foi considerado estatisticamente significativo. RESULTADOS: Neurodegeneração significativa foi detectada nos ratos que receberam uma únicainjeção ou injeções repetidas de sulfato de magnésio, em comparação com o grupo controle. O escore na avaliação histopatológica desse grupo também foi alto. CONCLUSÃO: Com base no exame de microscopia eletrônica, descobrimos que a administraçãointratecal de sulfato de magnésio induziu neurodegeneração.

BACKGROUND AND OBJECTIVES: To assess the potential neurotoxic effects at the ultrastructural level of magnesium sulfate administered intrathecally as a single or multi-dose. METHODS: Our study was conducted with 24 Sprague-Dawley rats that weighed 250-300 g. After a 4-hour fast, the rats were given 10 mg.kg-1 xylazine chloride intraperitoneal and then randomly allocated into three groups. Group I (n = 8) received 0.9% normal saline, Group II (n = 8) was given one intrathecal injection of 0.02 mL of 15% magnesium sulphate, and Group III (n = 8) was given 0.02 mL of 15% magnesium sulphate once a day for seven days. The injections were given within 0.40x50 mm from the lumbar area. After seven days, the animals were sacrificed under anesthesia with an aortic injection of 10% formaldehyde and their tissues were fixed. The medulla spinalis was then examined and histopathologically evaluated under an electron microscope. The Kruskal-Wallis test was used for statistical evaluation. A value of p < .05 was considered to be statistically significant. RESULTS: Significant neurodegeneration was detected in rats given single or repeated magnesium sulphate injections compared to the control group. The histopathological evaluation score of this group was also high. CONCLUSIONS: Based on electron microscopic examination, we found that intrathecal magnesium sulphate administration induced neurodegeneration.

JUSTIFICATIVA Y OBJETIVOS: Evaluar los potenciales efectos neurotóxicos en nivel ultraestructural de sulfuro de magnesio administrado por vía intratecal en dosis única o múltiple. MÉTODOS: Estudio realizado con 24 ratones Spraque-Dawley, con un peso promedio entre los 250 y los 300 g. Después del ayuno de 4 horas, los ratones recibieron 10 mg.kg-1 de cloruro de xilazina por vía intraperitoneal y enseguida fueron divididos aleatoriamente en tres grupos. El grupo I (n = 8) recibió 0,9% de suero fisiológico normal, Grupo II (n = 8) recibió una inyección de 0,02 mL de sulfuro de magnesio al 15% por vía intratecal y Grupo III (n = 8) recibió 0,02 mL de sulfuro de magnesio al 15% una vez por día durante siete días. Las inyecciones fueron aplicadas dentro de 0,40x50 milímetros del área lumbar. Después de siete días, los animales fueron sacrificados con anestesia con una inyección de formaldehido al 10% en la aorta y los tejidos fueron pegados. La médula espinal se examinó y fue histopatológicamente evaluada bajo microscopio electrónico. El test de Kruskal-Wallis fue usado para la evaluación estadística. Un valor de p < 0,05 fue considerado estadísticamente significativo. RESULTADOS: La neurodegeneración significativa fue detectada en los ratones que recibieron una sola inyección o inyecciones repetidas de sulfuro de magnesio, en comparación con el grupo control. El puntaje en la evaluación histopatológica de ese grupo también fue alto. CONCLUSIONES: Basándonos en el examen de microscopía electrónica, descubrimos que la administración intratecal de sulfuro de magnesio indujo a la neurodegeneración.

Assuntos

RESUMO

BACKGROUND AND OBJECTIVES: To assess the potential neurotoxic effects at the ultrastructural level of magnesium sulfate administered intrathecally as a single or multi-dose. METHODS: Our study was conducted with 24 Sprague-Dawley rats that weighed 250-300 g. After a 4-hour fast, the rats were given 10 mg.kg(-1) xylazine chloride intraperitoneal and then randomly allocated into three groups. Group I (n = 8) received 0.9% normal saline, Group II (n = 8) was given one intrathecal injection of 0.02 mL of 15% magnesium sulphate, and Group III (n = 8) was given 0.02 mL of 15% magnesium sulphate once a day for seven days. The injections were given within 0.40x50 mm from the lumbar area. After seven days, the animals were sacrificed under anesthesia with an aortic injection of 10% formaldehyde and their tissues were fixed. The medulla spinalis was then examined and histopathologically evaluated under an electron microscope. The Kruskal-Wallis test was used for statistical evaluation. A value of p < .05 was considered to be statistically significant. RESULTS: Significant neurodegeneration was detected in rats given single or repeated magnesium sulphate injections compared to the control group. The histopathological evaluation score of this group was also high. CONCLUSIONS: Based on electron microscopic examination, we found that intrathecal magnesium sulphate administration induced neurodegeneration.

Assuntos

RESUMO

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the unilaterality of subarachnoid block achieved with hyperbaric and hypobaric ropivacaine. METHODS: The prospective, randomized trial was conducted in an orthopedics surgical suite. In all, 60 ASA I-III patients scheduled for elective total knee arthroplasty were included in the study. Group Hypo (n=30) received 11.25mg of ropivacaine (7.5mg.mL(-1)) + 2mL of distilled water (density at room temperature was 0.997) and group Hyper (n=30) received 11.25mg of ropivacaine (7.5mg.mL(-1)) + 2mL (5mg.mL(-1)) of dextrose (density at room temperature was 1,015). Patients in the hyperbaric group were positioned with the operated side down and in the 15° Fowler position, versus those in the hypobaric group with the operated side facing up and in the 15° Trendelenburg position. Combined spinal epidural anesthesia was performed midline at the L(3-4) lumbar interspace. Hemodynamic and spinal block parameters, regression time, success of unilateral spinal anesthesia, patient comfort, surgical comfort, surgeon comfort, first analgesic requirement time, and adverse effects were assessed. RESULTS: Time to reach the T10 dermatome level on the operated side was shorter in group Hyper (612.00±163.29s) than in group Hypo (763.63±208.35s) (p<0.05). Time to 2-segment regression of the sensory block level on both the operated and non-operated sides was shorter in group Hypo than in group Hyper. CONCLUSION: Both hyperbaric and hypobaric ropivacaine (11.25mg) provided adequate and dependable anesthesia for total knee replacement surgery, with a high level of patient and surgeon comfort. Hypobaric local anesthetic solutions provide a high level of unilateral anesthesia, with rapid recovery of both sensory and motor block, and therefore may be preferable in outpatient settings.

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RESUMO

JUSTIFICATIVA E OBJETIVOS: O objetivo deste estudo foi comparar a unilateralidade do bloqueio subaracnoide obtido com ropivacaína hiperbárica e hipobárica. MÉTODOS: Estudo prospectivo aleatorizado conduzido em centro cirúrgico ortopédico. No total, 60 pacientes (ASA I-III) programados para cirurgia eletiva de artroplastia total do joelho foram incluídos no estudo. O grupo hipo (n = 30) recebeu 11,25 mg de ropivacaína (7,5 mg.mL-1) + 2 mL de água destilada (a densidade em temperatura ambiente foi 0,997) e o grupo hiper (n = 30) recebeu 11,25 mg de ropivacaína + 2 mL (5 mg.mL-1) de dextrose (a densidade em temperatura ambiente foi 1,015). Os pacientes no grupo hiperbárica foram posicionados com o lado operado para baixo e na posição de Fowler a 15º e os pacientes do grupo hipobárica foram posicionados com o lado operado para cima e na posição de Trendelenburg a 15º. O bloqueio combinado de raquianestesia e anestesia peridural (ACRP) foi realizado na linha mediana do interespaço lombar em L3 e L4. Foram avaliados os parâmetros hemodinâmicos e de bloqueio da coluna vertebral, tempo de regressão, sucesso da raquianestesia unilateral, conforto do paciente, do cirurgião e da cirurgia, tempo até a primeira requisição analgésica e efeitos adversos. RESULTADOS: O tempo necessário para atingir o nível de dermátomo T10 no lado operado foi menor no grupo hiper (612,00 ± 163,29 segundos) comparado ao grupo hipo (763,63 ± 208,35 segundos) (p < 0,05). O tempo para a regressão de dois segmentos do nível de bloqueio sensorial nos lados operado e não operado foi menor no grupo hipo do que no grupo hiper. CONCLUSÃO: A ropivacaína tanto hiperbárica quanto hipobárica (11,25 mg) proporcionou anestesia adequada e confiável para artroplastia total do joelho (ATJ), com um alto nível de conforto para o paciente e cirurgião. As soluções anestésicas hipobáricas locais fornecem um alto nível de anestesia unilateral, com rápida recuperação dos bloqueios sensitivo e motor e, portanto, pode ser preferível em regime ambulatorial.

BACKGROUND AND OBJECTIVES: The aim of this study was to compare the unilaterality of subarachnoid block achieved with hyperbaric and hypobaric ropivacaine. METHODS: The prospective, randomized trial was conducted in an orthopedics surgical suite. In all, 60 ASA I-III patients scheduled for elective total knee arthroplasty were included in the study. Group Hypo (n = 30) received 11.25 mg of ropivacaine (7.5 mg.mL-1) + 2 mL of distilled water (density at room temperature was 0.997) and group Hyper (n = 30) received 11.25 mg of ropivacaine (7.5 mg.mL-1) + 2 mL (5 mg.mL-1) of dextrose (density at room temperature was 1,015). Patients in the hyperbaric group were positioned with the operated side down and in the 15º Fowler position, versus those in the hypobaric group with the operated side facing up and in the 15º Trendelenburg position. Combined spinal epidural anesthesia was performed midline at the L3-4 lumbar interspace. Hemodynamic and spinal block parameters, regression time, success of unilateral spinal anesthesia, patient comfort, surgical comfort, surgeon comfort, first analgesic requirement time, and adverse effects were assessed. RESULTS: Time to reach the T10 dermatome level on the operated side was shorter in group Hyper (612.00 ± 163.29 s) than in group Hypo (763.63 ± 208.35 s) (p < 0.05). Time to 2-segment regression of the sensory block level on both the operated and non-operated sides was shorter in group Hypo than in group Hyper. CONCLUSION: Both hyperbaric and hypobaric ropivacaine (11.25 mg) provided adequate and dependable anesthesia for total knee replacement surgery, with a high level of patient and surgeon comfort. Hypobaric local anesthetic solutions provide a high level of unilateral anesthesia, with rapid recovery of both sensory and motor block, and therefore may be preferable in outpatient settings.

JUSTIFICATIVA Y OBJETIVOS: El objetivo de este estudio fue comparar la unilateralidad del bloqueo subaracnoideo logrado con la ropivacaína hiperbárica y con la ropivacaína hipobárica. MÉTODOS: El estudio randomizado y prospectivo fue llevado a cabo en una sala quirúrgica ortopédica. En total, 60 pacientes ASA I-III seleccionados para artoplastia electiva total de rodilla fueron incluidos en el estudio. El grupo Hipo (n = 30) recibió 11,25 mg de ropivacaína (7.5 mg.mL-1) + 2 mL de agua destilada (la densidad en la temperatura ambiente era de 0,997) y el grupo Hiper (n = 30) recibió 11,25 mg de ropivacaína + 2 mL (5 mg.mL-1) de dextrosa (la densidad en la temperatura ambiente era de 1,015). Los pacientes del grupo hiperbárica fueron colocados con el lado operado hacia abajo y en la posición de Fowler a 15º, y los pacientes del grupo hipobárica fueron colocados con el lado operado hacia arriba en la posición de Trendelenburg a 15º. El bloqueo combinado de raquianestesia y de anestesia epidural (CRP) fue realizado en la línea media del interespacio lumbar en L3 y L4. Se evaluaron los parámetros hemodinámico y de bloqueo de la columna vertebral, el tiempo de regresión, el éxito de la raquianestesia unilateral, la comodidad del paciente, la tranquilidad en la cirugía y la comodidad del cirujano, así como el tiempo requerido para la primera analgesia y los efectos adversos. RESULTADOS: El tiempo necesario para alcanzar el nivel del dermatoma T10 en el lado operado fue más corto en el grupo Hiper (612,00 ± 163,29 segundos) que en el grupo Hipo (763,63 ± 208,35 segundos) (p < 0,05). El tiempo para la regresión de los dos segmentos del nivel de bloqueo sensorial tanto en el lado operado como en el no operado, fue más corto en el grupo Hipo que en el grupo Hiper. CONCLUSIONES: Tanto la ropivacaína hiperbárica como la hipobárica (11,25 mg) han demostrado una anestesia adecuada y confiable para la artoplastia total de rodilla (ATR), con un alto nivel de comodidad tanto para el paciente como para el cirujano. Las soluciones anestésicas hipobáricas locales suministran un alto nivel de anestesia unilateral con una rápida recuperación de los bloqueos sensorial y motor, y por tanto, puede ser preferible en un régimen ambulatorial.

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