Neurotoxic effects of intrathecal magnesium sulphate.

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.

Efeitos neurotóxicos de sulfato de magnésio intratecal / Neurotoxic effects of intrathecal magnesium sulphate / Efectos neurotóxicos de sulfuro de magnesio intratecal

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.

Neurotoxic effects of intrathecal magnesium sulphate.

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.

Selective spinal anaesthesia with low-dose bupivacaine and bupivacaine + fentanyl in ambulatory arthroscopic knee surgery.

OBJECTIVE: To investigate the effects of selective spinal anaesthesia with low-dose bupivacaine alone and in combination with various doses of fentanyl, on blockage, haemodynamics, quality of anaesthesia, perioperative complications, and hospital release criteria. METHODS: This prospective study included 45 ASA I-II patients (age range: 20-77 years). The cases were randomised into 3 groups: Group 1 (n = 15) 0.8 ml of 4 mg 0.5% hyperbaric bupivacaine; Group 2 (n = 14) 1.3-ml solution of 4 mg 0.5% hyperbaric bupivacaine + 25 microg of fentanyl; and Group 3 (n = 14) 1.1-ml solution of 3 mg 0.5% hyperbaric bupivacaine + 25 microg of fentanyl. A double-blind design was employed and all patients were injected through L3-4 or L4-5 using a 25G point spinal needle. Sensory-motor blockage starting and ending time, maximum level of sensory-motor blockage, and grade and quality of anaesthesia were recorded. Haemodynamics, and respiration rates, and side effects were evaluated. Times for ability to pass to the stretcher without aid, walking, micturition, release from the hospital, and the first time an analgesic was needed were recorded. RESULTS: The time when an analgesic was first required was longer in the groups in which an opioid was added, and the shortest release time from the hospital was observed in Group 3. Other parameters remained similar across all groups. CONCLUSION: Low-dose bupivacaine, with or without fentanyl, can be used safely in lower extremity surgery and can provide rapid and safe release criteria.

Ropivacaine for unilateral spinal anesthesia; hyperbaric or hypobaric?

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.

Ropivacaína para raquianestesia unilateral: hiperbárica ou hipobárica? / Ropivacaine for unilateral spinal anesthesia; hyperbaric or hypobaric? / Ropivacaína para raquianestesia unilateral: ¿hiperbárica o hipobárica?

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.

Pre-emptive analgesic and haemodynamic efficacy of combined spinal-epidural neostigmine delivery.

OBJECTIVE: To determine the effect of pre-emptive epidurally administered 4 or 8 mcg/kg neostigmine on analgesia, mean arterial pressure, heart rate and side effects in intra and postoperative period. STUDY DESIGN: Randomized, double blinded, controlled clinical trial. PLACE AND DURATION OF STUDY: Ankara Numune Training and Research Hospital, Turkey, from January to December 2008. METHODOLOGY: Forty-five patients scheduled for lower extremity surgery were included in the study following the approval of the ethics committee and the patients. The study group was split into three groups and received combined spinalepidural anaesthesia. Diluting with 10 ml normal saline, group N4 and group N8 were delivered 4 mcg/kg and 8 mcg/kg epidural neostigmine, respectively, whereas group SF received 10 ml epidural saline. Lidocaine (2%) at 1.2 mg/kg dose was preferred for spinal anaesthesia. Analgesic efficacy, time to first analgesic requirement, Visual Analog Scale, Fentanyl consumption in the postoperative patient-controlled epidural analgesia, and delivered/required number of boluses, were evaluated. Haemodynamic data and side effects were noted. RESULTS: Statistically, analgesic consumptions at 12 and 24 hours in the N8 group was lower than those in the SF group, the number of delivered boluses was lower in the N8 group compared with the SF and N4 groups, number of required boluses was lower in the N8 group than in the SF group. In terms of haemodynamics and side effects, no difference was found between the groups regarding the entire intraoperative and postoperative parameters. CONCLUSION: Epidural Neostigmine administration at 8 mcg/kg was found to be a viable additional agent against analgesia, with the postoperative period depending on the dosage.

Comparison of 0.25% levobupivacaine and 0.25% bupivacaine for posterior approach interscalene brachial plexus block.

PURPOSE: This study compares the onset time and quality of posterior approach interscalene brachial plexus block produced by 0.25% levobupivacaine and 0.25% bupivacaine. METHODS: Sixty adult patients undergoing open or closed shoulder surgery were enrolled in this double-blind, randomized study, and they were randomly allocated to receive 40 ml of 0.25% levobupivacaine (Group L, n = 30) or 0.25% bupivacaine (Group B, n = 30). The patients were assessed at 5 min intervals after local anesthetic injection in order to determine loss of shoulder abduction and loss of pinprick sensation in the C(5-6) dermatomes. The mean onset time of motor and sensory block and onset time of complete motor and sensory block were documented in both groups. RESULTS: In both groups, mean onset time of sensory block was <5 min and mean onset time of complete sensory block was <25 min. The onset times for sensory block and complete sensory block were not statistically different between the groups (P > 0.05). In both groups, mean onset time of motor block was <10 min but the mean onset time of complete motor block was <30 min. The onset times of motor block and complete motor block were not statistically different among the groups (P > 0.05). After the injection of the local anesthetic, 27% of Group L and 87% of Group B had complete motor block. Four patients in Group L had no motor block. CONCLUSION: We conclude that 0.25% levobupivacaine and 0.25% bupivacaine have similar motor and sensory block onset times and qualities when used in posterior approach interscalene brachial plexus block, and provide comfortable anesthesia and analgesia for shoulder surgery.

Selective spinal anesthesia for inguinal herniorrhaphy.

OBJECTIVE: To determine the characteristic profiles of 2 hypobaric spinal anesthetic solutions for selective spinal anesthesia in inguinal herniorrhaphy. METHODS: The study took place in the general surgery room of Anesthesia Department, Ankara Numune Research and Training Hospital between May and July 2005 as a prospective, randomized and double-blind trial. Sixty-one ASA I-III patients scheduled for inguinal herniorrhaphy were randomly divided into 2 groups. Group R received combined spinal epidural anesthesia with ropivacaine 7.5 mg and group B received bupivacaine 5 mg; in both groups 25 ug of fentanyl was added. Solutions were diluted with 1.5 ml of sterile water. A Portex 18/27 or 16/27 needle was inserted at L1-2 or L2-3 with patients sitting upright; surgery began after the sensory block reached the T6 dermatome. Sensory and motor block characteristics, hemodynamic data, side effects, recovery time, the timing of the onset of pain, and the walkout were assessed. RESULTS: Motor block duration was shorter in Group R (56.1 +/- 36.1 minutes versus 72.5 +/- 23.3 minutes) (p=0.013). Complete motor block duration was shorter in Group R. There was no difference between the 2 groups. Intra-group analysis showed that hemodynamic values after anesthesia induction were lower than initial values. CONCLUSION: Ropivacaine plus fentanyl provided similar sensory anesthesia, but with a shorter duration of motor block than bupivacaine plus fentanyl when used for selective spinal anesthesia in herniorrhaphy surgery. Furthermore, we suggest that hemodynamic should be carefully monitored during surgery.

Unilateral pudendal nerve blockade for relief of all pain during transrectal ultrasound-guided biopsy of the prostate: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: To investigate the efficacy of unilateral pudendal nerve block for the relief of all pain during transrectal ultrasound (TRUS)-guided prostate biopsy. TRUS-guided prostate biopsy is the standard procedure to diagnose or rule out prostate cancer. The pain, attributed to ultrasound probe insertion and the needle punctures into the prostate, inflicted by TRUS-guided prostate biopsy limits its effectiveness. METHODS: We performed a prospective, randomized, double-blind, placebo-controlled study of 65 consecutive men suspected of having prostate cancer who were undergoing TRUS-guided prostate biopsy, 51 of whom fulfilled the inclusion criteria. Before the biopsy, each patient was randomized to one of two groups. Both the patient and the physician who performed the TRUS-guided biopsy were unaware of the contents of the injection for the pudendal nerve block. Unilateral pudendal nerve blockade was performed transperineally with digital rectal examination guidance using 10 mg of 1% prilocaine (group 1 [n = 26]) or 10 mL of a 0.9 NaCl solution (group 2 [n = 25]) by way of a 22-gauge spinal needle by the same anesthetist. Pain was evaluated using an 11-point visual analog scale questionnaire. RESULTS: No statistically significant differences were found in the visual analog scale score for pain during the pudendal nerve blockade or digital rectal examination between the groups. A statistically significant difference was found in the visual analog scale score for the biopsy procedure (P < 0.01) and probe discomfort (P < 0.05) between the two groups. CONCLUSIONS: Unilateral pudendal nerve blockade was effective in reducing the pain at both biopsy and probe manipulation in our study.