César Romão Martins

Effects of melatonin on behavioral dopaminergic supersensitivity

This study examines the effects of melatonin on dopaminergic supersensitivity induced by long-term treatment with haloperidol in rats. Enhancements of spontaneous general activity in an open-field and of stereotyped behavior induced by apomorphine after abrupt withdrawal from long-term treatment with haloperidol were used as experimental parameters for dopaminergic supersensitivity. Experiment 1 was conducted to investigate the effects of melatonin on the development of dopaminergic supersensitivity, and experiment 2 was conducted to investigate the effects of melatonin on the development as well as on expression of dopaminergic supersensitivity. Rats of both experiments were long-term treated with saline or haloperidol concomitant to saline or melatonin. In experiment 1 behavioral observations were performed after abrupt withdrawal from long-term treatment. In experiment 2 behavioral observations were performed 1 hour after an acute injection of saline or melatonin, administered after the abrupt withdrawal from long-term treatment. Both behavioral parameters used showed the development of central dopaminergic supersensitivity in rats treated with haloperidol since 24 hours after abrupt withdrawal. Concomitant treatment with melatonin intensified haloperidol-induced dopaminergic supersensitivity, observed 72 hours after withdrawal. Melatonin treatment per se also induced behavioral supersensitivity evaluated by both open-field and stereotyped behaviors, although it was more fugacious than that presented by haloperidol. Acute treatment with melatonin reverted the enhancement of the haloperidol-induced dopaminergic supersensitivity produced by concomitant long-term treatment with melatonin, as well as melatonin-induced dopaminergic supersensitivity per se. Our results support previous evidence of antidopaminergic effects of melatonin and demonstrate that repeated administration of this hormone modifies the plasticity of behaviors mediated by central dopaminergic systems.

Efeitos da lidocaína por via venosa sobre a farmacodinâmica do rocurônio

BACKGROUND AND OBJECTIVES Rocuronium is an intermediate nondepolarizing neuromuscular blocker (NMB) with faster onset and indicated in situations requiring rapid tracheal intubation. Intravenous lidocaine is often used to decrease hemodynamic responses to tracheal intubation. The association of NMB to local anesthetics results in potentiation of NMB effects. The purpose of this study was to evaluate the influence of lidocaine on rocuroniums pharmacodynamics determined by acceleromyography. METHODS Forty-six ASA I-II patients, aged 18 to 65 years, were randomly distributed in two groups (CG: control and LG: lidocaine). Rocuronium was given to all patients for neuromuscular block. LG received lidocaine (1.5 mg.kg(-1)) 3 minutes before rocuronium. Neuromuscular function was evaluated by adductor pollicis muscle response to TOF. After NMB injection, times for first TOF response (T(1)) to reach 10 and 0% of baseline value and recover 25%, 75% and 95% of contraction height (Dur(25%), Dur(75%), Dur(95%)) were recorded. Recovery time of T(4)/T(1) = 0.8 and intervals Dur(75%)-Dur(25%) (IR(25-75)) and T(4)/T(1) = 0.8 - Dur(25%) were also recorded. RESULTS This study has not shown statistically significant differences between groups when T(1)= 10%, T(1) = 0, RI(25-75), T(4)/T(1) = 0.8 - Dur(25)% were compared. Times for Dur(25%), Dur(75%), Dur(95%) in LG were significantly higher as compared to CG. CONCLUSIONS Lidocaine associated to rocuronium has prolonged early blockade recovery stage without interfering with onset or late recovery stage.JUSTIFICATIVA Y OBJETIVOS: El rocuronio es un bloqueador neuromuscular (BNM) no despolarizante de accion intermediaria que presenta un inicio de accion mas rapido, indicado para situaciones donde hay necesidad de rapida intubacion traqueal. La lidocaina es frecuentemente utilizada por via venosa para disminuir las respuestas hemodinamicas asociadas a la intubacion traqueal. La asociacion de un BNM a un anestesico local resulta en potencializacion de los efectos bloqueadores neuromusculares. El objetivo de este estudio es evaluar la interaccion entre la lidocaina y a farmacodinamica del rocuronio evaluada por aceleromiografia. METODO: Pacientes estado fisico ASA I y II, con edad entre 18 y 65 anos, eventualmente distribuidos en dos grupos (GC: control y GL: lidocaina), recibieron rocuronio como bloqueador neuromuscular. El GL recibio lidocaina (1,5 mg.kg-1) 3 minutos antes del rocuronio. La funcion neuromuscular fue evaluada por la respuesta del musculo aductor del pulgar a la secuencia de cuatro estimulos (SQE). Despues de la inyeccion del BNM se anotaron los tiempos para la primera respuesta (T1) a la SQE alcanzar 10 y 0% del valor control, y recobrar 25%, 75% y 95% de la altura de la contraccion (Dur25%, Dur75%, Dur95%). Se anoto tambien el tiempo de recuperacion de T4/T1 = 0,8) y los intervalos Dur75%-Dur25% (IR25-75) y T4/T1 = 0,8 - Dur25%. RESULTADOS: Este estudio no demostro diferencia estadisticamente significativa entre los grupos cuando comparados T1= 10%, T1 = 0, IR25-75, T4/T1 = 0,8 - Dur25%. Los tiempos para Dur25%, Dur75%, Dur95% en el GL fueron estadisticamente superiores a los del GC. CONCLUSIONES: La asociacion de lidocaina al rocuronio prolongo la parte inicial de recuperacion del bloqueo sin interferir con el inicio de accion o con la parte de recuperacion final.

Effects of dexmedetomidine on blood coagulation evaluated by thromboelastography

BACKGROUND AND OBJECTIVES Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist used in anesthesia for its hypnoanalgesic and cardiovascular effects. Stimulation of alpha2-adrenoceptors may determine pro and anti-platelet aggregation effects through direct and indirect mechanisms. This study aimed at determining the effects of dexmedetomidine on coagulation evaluated by thromboelastography. METHODS Twenty four patients were randomly distributed in 3 groups: Group 1 patients received saline solution (control group), Group 2 patients received 1 microg.kg-1 dexmedetomidine in 10 minutes, followed by 0.4 microg.kg-1.h-1 infusion for 20 minutes and Group 3 patients received 0.05 mg.kg-1 midazolam. Sedated patients maintained scores 3 or 4 in Ramsays sedation scale. Blood samples were collected before and 30 minutes after the treatment for thromboelastography. RESULTS Dexmedetomidine has significantly increased reaction time (parameter R) and decreased coagulation index in final curves as compared to initial ones. Values, however, have remained within ranges accepted as normal. This phenomenon was not observed in remaining groups. CONCLUSIONS Dexmedetomidine pro and anti-platelet aggregation mechanisms interaction determines mild hypocoagulation, however maintaining coagulation within normal ranges. Dexmedetomidine effects on coagulation are probably not mediated by anxiolysis, since sedation was equivalent to the midazolam group.JUSTIFICATIVA E OBJETIVOS: A dexmedetomidina e um agente agonista dos receptores adrenergicos a2 altamente seletivo, usado em anestesia por seus efeitos hipnoanalgesicos e pela estabilidade cardiovascular. O estimulo dos receptores adrenergicos a2 pode apresentar efeitos pro e antiagregantes plaquetarios, por mecanismos diretos e indiretos. No presente estudo, avaliaram-se os efeitos da dexmedetomidina sobre a coagulacao atraves do metodo da tromboelastografia. METODO: Vinte e quatro pacientes foram aleatoriamente divididos em tres grupos. Os pacientes do grupo 1 receberam infusao de solucao fisiologica (controle), os do grupo 2 receberam dexmedetomidina na dose de 1 µg.kg-1 em 10 minutos, seguida da infusao de 0,4 µg.kg-1.h-1 por 20 minutos e os do grupo 3 receberam midazolam na dose de 0,05 mg.kg-1. Os pacientes sedados mantiveram indices 3 ou 4 na escala da sedacao de Ramsay. Foram coletadas amostras de sangue e obtidos tracados de tromboelastografia previamente e apos 30 minutos do tratamento. RESULTADOS: A dexmedetomidina, de forma estatisticamente significativa, aumentou o tempo de reacao (parâmetro R) e diminuiu o indice de coagulacao nos tracados finais em relacao aos iniciais. No entanto, os valores permaneceram dentro dos intervalos considerados normais. Este fenomeno nao foi observado nos demais grupos. CONCLUSOES: A interacao dos mecanismos pro e antiagregantes da dexmedetomidina leva a discreta hipocoagulacao; porem, mantem a coagulacao dentro de parâmetros considerados normais. Os efeitos da dexmedetomidina sobre a coagulacao provavelmente nao ocorrem pela ansiolise, uma vez que a sedacao foi igual ao grupo que recebeu midazolam.

Efeitos da dexmedetomidina sobre a coagulação sangüínea avaliada através do método da tromboelastografia

BACKGROUND AND OBJECTIVES Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist used in anesthesia for its hypnoanalgesic and cardiovascular effects. Stimulation of alpha2-adrenoceptors may determine pro and anti-platelet aggregation effects through direct and indirect mechanisms. This study aimed at determining the effects of dexmedetomidine on coagulation evaluated by thromboelastography. METHODS Twenty four patients were randomly distributed in 3 groups: Group 1 patients received saline solution (control group), Group 2 patients received 1 microg.kg-1 dexmedetomidine in 10 minutes, followed by 0.4 microg.kg-1.h-1 infusion for 20 minutes and Group 3 patients received 0.05 mg.kg-1 midazolam. Sedated patients maintained scores 3 or 4 in Ramsays sedation scale. Blood samples were collected before and 30 minutes after the treatment for thromboelastography. RESULTS Dexmedetomidine has significantly increased reaction time (parameter R) and decreased coagulation index in final curves as compared to initial ones. Values, however, have remained within ranges accepted as normal. This phenomenon was not observed in remaining groups. CONCLUSIONS Dexmedetomidine pro and anti-platelet aggregation mechanisms interaction determines mild hypocoagulation, however maintaining coagulation within normal ranges. Dexmedetomidine effects on coagulation are probably not mediated by anxiolysis, since sedation was equivalent to the midazolam group.JUSTIFICATIVA E OBJETIVOS: A dexmedetomidina e um agente agonista dos receptores adrenergicos a2 altamente seletivo, usado em anestesia por seus efeitos hipnoanalgesicos e pela estabilidade cardiovascular. O estimulo dos receptores adrenergicos a2 pode apresentar efeitos pro e antiagregantes plaquetarios, por mecanismos diretos e indiretos. No presente estudo, avaliaram-se os efeitos da dexmedetomidina sobre a coagulacao atraves do metodo da tromboelastografia. METODO: Vinte e quatro pacientes foram aleatoriamente divididos em tres grupos. Os pacientes do grupo 1 receberam infusao de solucao fisiologica (controle), os do grupo 2 receberam dexmedetomidina na dose de 1 µg.kg-1 em 10 minutos, seguida da infusao de 0,4 µg.kg-1.h-1 por 20 minutos e os do grupo 3 receberam midazolam na dose de 0,05 mg.kg-1. Os pacientes sedados mantiveram indices 3 ou 4 na escala da sedacao de Ramsay. Foram coletadas amostras de sangue e obtidos tracados de tromboelastografia previamente e apos 30 minutos do tratamento. RESULTADOS: A dexmedetomidina, de forma estatisticamente significativa, aumentou o tempo de reacao (parâmetro R) e diminuiu o indice de coagulacao nos tracados finais em relacao aos iniciais. No entanto, os valores permaneceram dentro dos intervalos considerados normais. Este fenomeno nao foi observado nos demais grupos. CONCLUSOES: A interacao dos mecanismos pro e antiagregantes da dexmedetomidina leva a discreta hipocoagulacao; porem, mantem a coagulacao dentro de parâmetros considerados normais. Os efeitos da dexmedetomidina sobre a coagulacao provavelmente nao ocorrem pela ansiolise, uma vez que a sedacao foi igual ao grupo que recebeu midazolam.

Effects of intravenous lidocaine on the pharmacodynamics of rocuronium

BACKGROUND AND OBJECTIVES Rocuronium is an intermediate nondepolarizing neuromuscular blocker (NMB) with faster onset and indicated in situations requiring rapid tracheal intubation. Intravenous lidocaine is often used to decrease hemodynamic responses to tracheal intubation. The association of NMB to local anesthetics results in potentiation of NMB effects. The purpose of this study was to evaluate the influence of lidocaine on rocuroniums pharmacodynamics determined by acceleromyography. METHODS Forty-six ASA I-II patients, aged 18 to 65 years, were randomly distributed in two groups (CG: control and LG: lidocaine). Rocuronium was given to all patients for neuromuscular block. LG received lidocaine (1.5 mg.kg(-1)) 3 minutes before rocuronium. Neuromuscular function was evaluated by adductor pollicis muscle response to TOF. After NMB injection, times for first TOF response (T(1)) to reach 10 and 0% of baseline value and recover 25%, 75% and 95% of contraction height (Dur(25%), Dur(75%), Dur(95%)) were recorded. Recovery time of T(4)/T(1) = 0.8 and intervals Dur(75%)-Dur(25%) (IR(25-75)) and T(4)/T(1) = 0.8 - Dur(25%) were also recorded. RESULTS This study has not shown statistically significant differences between groups when T(1)= 10%, T(1) = 0, RI(25-75), T(4)/T(1) = 0.8 - Dur(25)% were compared. Times for Dur(25%), Dur(75%), Dur(95%) in LG were significantly higher as compared to CG. CONCLUSIONS Lidocaine associated to rocuronium has prolonged early blockade recovery stage without interfering with onset or late recovery stage.JUSTIFICATIVA Y OBJETIVOS: El rocuronio es un bloqueador neuromuscular (BNM) no despolarizante de accion intermediaria que presenta un inicio de accion mas rapido, indicado para situaciones donde hay necesidad de rapida intubacion traqueal. La lidocaina es frecuentemente utilizada por via venosa para disminuir las respuestas hemodinamicas asociadas a la intubacion traqueal. La asociacion de un BNM a un anestesico local resulta en potencializacion de los efectos bloqueadores neuromusculares. El objetivo de este estudio es evaluar la interaccion entre la lidocaina y a farmacodinamica del rocuronio evaluada por aceleromiografia. METODO: Pacientes estado fisico ASA I y II, con edad entre 18 y 65 anos, eventualmente distribuidos en dos grupos (GC: control y GL: lidocaina), recibieron rocuronio como bloqueador neuromuscular. El GL recibio lidocaina (1,5 mg.kg-1) 3 minutos antes del rocuronio. La funcion neuromuscular fue evaluada por la respuesta del musculo aductor del pulgar a la secuencia de cuatro estimulos (SQE). Despues de la inyeccion del BNM se anotaron los tiempos para la primera respuesta (T1) a la SQE alcanzar 10 y 0% del valor control, y recobrar 25%, 75% y 95% de la altura de la contraccion (Dur25%, Dur75%, Dur95%). Se anoto tambien el tiempo de recuperacion de T4/T1 = 0,8) y los intervalos Dur75%-Dur25% (IR25-75) y T4/T1 = 0,8 - Dur25%. RESULTADOS: Este estudio no demostro diferencia estadisticamente significativa entre los grupos cuando comparados T1= 10%, T1 = 0, IR25-75, T4/T1 = 0,8 - Dur25%. Los tiempos para Dur25%, Dur75%, Dur95% en el GL fueron estadisticamente superiores a los del GC. CONCLUSIONES: La asociacion de lidocaina al rocuronio prolongo la parte inicial de recuperacion del bloqueo sin interferir con el inicio de accion o con la parte de recuperacion final.

[Complication related to tracheal bronchus in infant: case report.].

BACKGROUND AND OBJECTIVES Tracheal bronchus is a congenital abnormality affecting approximately 2% of general population, usually asymptomatic and of incidental diagnosis. It is characterized by the presence of the bronchus to the right upper lobe emerging directly from the trachea, close to the carina. Tracheal tube may obliterate its lumen, leading to right upper lobe atelectasis. This article aimed at reporting a case of right upper lobe atelectasis in infant, noticed after tracheal intubation, and also presenting a literature review on this abnormality, highlighting its anesthetic implications. CASE REPORT Male patient, mulatto, 5 months old, 5 kg, physical status ASA I, scheduled for anorectal fistula correction (Mini-Peña). Right subclavian vein was punctured after tracheal intubation, followed by desaturation and decreased right apex vesical murmur. Initial hypotheses were hemothorax, pneumothorax, bronchial secretion and selective intubation. Chest X-rays have shown right upper lobe atelectasis. Bronchoscopy revealed tracheal bronchus. Tube was repositioned with re-expansion of the affected lobe. CONCLUSIONS Because of its relatively high incidence (2%), tracheal bronchus should be included among right upper lobe atelectasis differential diagnoses.JUSTIFICATIVA E OBJETIVOS: O bronquio traqueal e uma anomalia congenita com incidencia aproximada de 2% na populacao geral, habitualmente assintomatica e de diagnostico usualmente incidental. Esta anomalia caracteriza-se pela presenca de bronquio para o lobo superior direito emergindo diretamente da traqueia, junto a carina. Em vigencia de intubacao traqueal, este bronquio pode ter sua luz obliterada pela cânula, levando a atelectasia isolada do lobo superior direito. O objetivo deste artigo foi relatar um caso de atelectasia isolada de lobo superior direito em lactente, percebida apos intubacao orotraqueal, bem como fazer uma revisao de literatura sobre esta anomalia, destacando suas implicacoes anestesicas. RELATO DO CASO: Paciente do sexo masculino, pardo, 5 meses de idade, 5 kg, estado fisico ASA I, portador de fistula anorretal, em programacao para correcao da fistula (Mini-Pena). Apos intubacao orotraqueal realizou-se puncao de veia subclavia direita, que foi seguida de dessaturacao e diminuicao do murmurio vesicular no apice direito. As hipoteses iniciais foram de hemotorax, pneumotorax, secrecao bronquica e intubacao seletiva. Foi realizada radiografia de torax, que mostrou atelectasia de lobo superior direito. Realizada broncoscopia, que revelou bronquio traqueal. A cânula foi reposicionada, com re-expansao do lobo atelectasiado. CONCLUSOES: Por ser uma anomalia de incidencia relativamente alta (2%), o bronquio traqueal deve ser incluido entre os diagnosticos diferenciais de atelectasia de lobo superior direito.

Complicación debida a la presencia de bronquiotraqueal en un lactante: relato de caso

BACKGROUND AND OBJECTIVES Tracheal bronchus is a congenital abnormality affecting approximately 2% of general population, usually asymptomatic and of incidental diagnosis. It is characterized by the presence of the bronchus to the right upper lobe emerging directly from the trachea, close to the carina. Tracheal tube may obliterate its lumen, leading to right upper lobe atelectasis. This article aimed at reporting a case of right upper lobe atelectasis in infant, noticed after tracheal intubation, and also presenting a literature review on this abnormality, highlighting its anesthetic implications. CASE REPORT Male patient, mulatto, 5 months old, 5 kg, physical status ASA I, scheduled for anorectal fistula correction (Mini-Peña). Right subclavian vein was punctured after tracheal intubation, followed by desaturation and decreased right apex vesical murmur. Initial hypotheses were hemothorax, pneumothorax, bronchial secretion and selective intubation. Chest X-rays have shown right upper lobe atelectasis. Bronchoscopy revealed tracheal bronchus. Tube was repositioned with re-expansion of the affected lobe. CONCLUSIONS Because of its relatively high incidence (2%), tracheal bronchus should be included among right upper lobe atelectasis differential diagnoses.JUSTIFICATIVA E OBJETIVOS: O bronquio traqueal e uma anomalia congenita com incidencia aproximada de 2% na populacao geral, habitualmente assintomatica e de diagnostico usualmente incidental. Esta anomalia caracteriza-se pela presenca de bronquio para o lobo superior direito emergindo diretamente da traqueia, junto a carina. Em vigencia de intubacao traqueal, este bronquio pode ter sua luz obliterada pela cânula, levando a atelectasia isolada do lobo superior direito. O objetivo deste artigo foi relatar um caso de atelectasia isolada de lobo superior direito em lactente, percebida apos intubacao orotraqueal, bem como fazer uma revisao de literatura sobre esta anomalia, destacando suas implicacoes anestesicas. RELATO DO CASO: Paciente do sexo masculino, pardo, 5 meses de idade, 5 kg, estado fisico ASA I, portador de fistula anorretal, em programacao para correcao da fistula (Mini-Pena). Apos intubacao orotraqueal realizou-se puncao de veia subclavia direita, que foi seguida de dessaturacao e diminuicao do murmurio vesicular no apice direito. As hipoteses iniciais foram de hemotorax, pneumotorax, secrecao bronquica e intubacao seletiva. Foi realizada radiografia de torax, que mostrou atelectasia de lobo superior direito. Realizada broncoscopia, que revelou bronquio traqueal. A cânula foi reposicionada, com re-expansao do lobo atelectasiado. CONCLUSOES: Por ser uma anomalia de incidencia relativamente alta (2%), o bronquio traqueal deve ser incluido entre os diagnosticos diferenciais de atelectasia de lobo superior direito.

Complicação decorrente da presença de brônquio traqueal em lactente: relato de caso

BACKGROUND AND OBJECTIVES Tracheal bronchus is a congenital abnormality affecting approximately 2% of general population, usually asymptomatic and of incidental diagnosis. It is characterized by the presence of the bronchus to the right upper lobe emerging directly from the trachea, close to the carina. Tracheal tube may obliterate its lumen, leading to right upper lobe atelectasis. This article aimed at reporting a case of right upper lobe atelectasis in infant, noticed after tracheal intubation, and also presenting a literature review on this abnormality, highlighting its anesthetic implications. CASE REPORT Male patient, mulatto, 5 months old, 5 kg, physical status ASA I, scheduled for anorectal fistula correction (Mini-Peña). Right subclavian vein was punctured after tracheal intubation, followed by desaturation and decreased right apex vesical murmur. Initial hypotheses were hemothorax, pneumothorax, bronchial secretion and selective intubation. Chest X-rays have shown right upper lobe atelectasis. Bronchoscopy revealed tracheal bronchus. Tube was repositioned with re-expansion of the affected lobe. CONCLUSIONS Because of its relatively high incidence (2%), tracheal bronchus should be included among right upper lobe atelectasis differential diagnoses.JUSTIFICATIVA E OBJETIVOS: O bronquio traqueal e uma anomalia congenita com incidencia aproximada de 2% na populacao geral, habitualmente assintomatica e de diagnostico usualmente incidental. Esta anomalia caracteriza-se pela presenca de bronquio para o lobo superior direito emergindo diretamente da traqueia, junto a carina. Em vigencia de intubacao traqueal, este bronquio pode ter sua luz obliterada pela cânula, levando a atelectasia isolada do lobo superior direito. O objetivo deste artigo foi relatar um caso de atelectasia isolada de lobo superior direito em lactente, percebida apos intubacao orotraqueal, bem como fazer uma revisao de literatura sobre esta anomalia, destacando suas implicacoes anestesicas. RELATO DO CASO: Paciente do sexo masculino, pardo, 5 meses de idade, 5 kg, estado fisico ASA I, portador de fistula anorretal, em programacao para correcao da fistula (Mini-Pena). Apos intubacao orotraqueal realizou-se puncao de veia subclavia direita, que foi seguida de dessaturacao e diminuicao do murmurio vesicular no apice direito. As hipoteses iniciais foram de hemotorax, pneumotorax, secrecao bronquica e intubacao seletiva. Foi realizada radiografia de torax, que mostrou atelectasia de lobo superior direito. Realizada broncoscopia, que revelou bronquio traqueal. A cânula foi reposicionada, com re-expansao do lobo atelectasiado. CONCLUSOES: Por ser uma anomalia de incidencia relativamente alta (2%), o bronquio traqueal deve ser incluido entre os diagnosticos diferenciais de atelectasia de lobo superior direito.

Efectos de la lidocaína por vía venosa sobre la farmacodinámica del rocuronio

BACKGROUND AND OBJECTIVES Rocuronium is an intermediate nondepolarizing neuromuscular blocker (NMB) with faster onset and indicated in situations requiring rapid tracheal intubation. Intravenous lidocaine is often used to decrease hemodynamic responses to tracheal intubation. The association of NMB to local anesthetics results in potentiation of NMB effects. The purpose of this study was to evaluate the influence of lidocaine on rocuroniums pharmacodynamics determined by acceleromyography. METHODS Forty-six ASA I-II patients, aged 18 to 65 years, were randomly distributed in two groups (CG: control and LG: lidocaine). Rocuronium was given to all patients for neuromuscular block. LG received lidocaine (1.5 mg.kg(-1)) 3 minutes before rocuronium. Neuromuscular function was evaluated by adductor pollicis muscle response to TOF. After NMB injection, times for first TOF response (T(1)) to reach 10 and 0% of baseline value and recover 25%, 75% and 95% of contraction height (Dur(25%), Dur(75%), Dur(95%)) were recorded. Recovery time of T(4)/T(1) = 0.8 and intervals Dur(75%)-Dur(25%) (IR(25-75)) and T(4)/T(1) = 0.8 - Dur(25%) were also recorded. RESULTS This study has not shown statistically significant differences between groups when T(1)= 10%, T(1) = 0, RI(25-75), T(4)/T(1) = 0.8 - Dur(25)% were compared. Times for Dur(25%), Dur(75%), Dur(95%) in LG were significantly higher as compared to CG. CONCLUSIONS Lidocaine associated to rocuronium has prolonged early blockade recovery stage without interfering with onset or late recovery stage.JUSTIFICATIVA Y OBJETIVOS: El rocuronio es un bloqueador neuromuscular (BNM) no despolarizante de accion intermediaria que presenta un inicio de accion mas rapido, indicado para situaciones donde hay necesidad de rapida intubacion traqueal. La lidocaina es frecuentemente utilizada por via venosa para disminuir las respuestas hemodinamicas asociadas a la intubacion traqueal. La asociacion de un BNM a un anestesico local resulta en potencializacion de los efectos bloqueadores neuromusculares. El objetivo de este estudio es evaluar la interaccion entre la lidocaina y a farmacodinamica del rocuronio evaluada por aceleromiografia. METODO: Pacientes estado fisico ASA I y II, con edad entre 18 y 65 anos, eventualmente distribuidos en dos grupos (GC: control y GL: lidocaina), recibieron rocuronio como bloqueador neuromuscular. El GL recibio lidocaina (1,5 mg.kg-1) 3 minutos antes del rocuronio. La funcion neuromuscular fue evaluada por la respuesta del musculo aductor del pulgar a la secuencia de cuatro estimulos (SQE). Despues de la inyeccion del BNM se anotaron los tiempos para la primera respuesta (T1) a la SQE alcanzar 10 y 0% del valor control, y recobrar 25%, 75% y 95% de la altura de la contraccion (Dur25%, Dur75%, Dur95%). Se anoto tambien el tiempo de recuperacion de T4/T1 = 0,8) y los intervalos Dur75%-Dur25% (IR25-75) y T4/T1 = 0,8 - Dur25%. RESULTADOS: Este estudio no demostro diferencia estadisticamente significativa entre los grupos cuando comparados T1= 10%, T1 = 0, IR25-75, T4/T1 = 0,8 - Dur25%. Los tiempos para Dur25%, Dur75%, Dur95% en el GL fueron estadisticamente superiores a los del GC. CONCLUSIONES: La asociacion de lidocaina al rocuronio prolongo la parte inicial de recuperacion del bloqueo sin interferir con el inicio de accion o con la parte de recuperacion final.

Efectos de la dexmedetomidina sobre la coagulación sanguínea evaluada a través del método de la tromboelastografía

BACKGROUND AND OBJECTIVES Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist used in anesthesia for its hypnoanalgesic and cardiovascular effects. Stimulation of alpha2-adrenoceptors may determine pro and anti-platelet aggregation effects through direct and indirect mechanisms. This study aimed at determining the effects of dexmedetomidine on coagulation evaluated by thromboelastography. METHODS Twenty four patients were randomly distributed in 3 groups: Group 1 patients received saline solution (control group), Group 2 patients received 1 microg.kg-1 dexmedetomidine in 10 minutes, followed by 0.4 microg.kg-1.h-1 infusion for 20 minutes and Group 3 patients received 0.05 mg.kg-1 midazolam. Sedated patients maintained scores 3 or 4 in Ramsays sedation scale. Blood samples were collected before and 30 minutes after the treatment for thromboelastography. RESULTS Dexmedetomidine has significantly increased reaction time (parameter R) and decreased coagulation index in final curves as compared to initial ones. Values, however, have remained within ranges accepted as normal. This phenomenon was not observed in remaining groups. CONCLUSIONS Dexmedetomidine pro and anti-platelet aggregation mechanisms interaction determines mild hypocoagulation, however maintaining coagulation within normal ranges. Dexmedetomidine effects on coagulation are probably not mediated by anxiolysis, since sedation was equivalent to the midazolam group.JUSTIFICATIVA E OBJETIVOS: A dexmedetomidina e um agente agonista dos receptores adrenergicos a2 altamente seletivo, usado em anestesia por seus efeitos hipnoanalgesicos e pela estabilidade cardiovascular. O estimulo dos receptores adrenergicos a2 pode apresentar efeitos pro e antiagregantes plaquetarios, por mecanismos diretos e indiretos. No presente estudo, avaliaram-se os efeitos da dexmedetomidina sobre a coagulacao atraves do metodo da tromboelastografia. METODO: Vinte e quatro pacientes foram aleatoriamente divididos em tres grupos. Os pacientes do grupo 1 receberam infusao de solucao fisiologica (controle), os do grupo 2 receberam dexmedetomidina na dose de 1 µg.kg-1 em 10 minutos, seguida da infusao de 0,4 µg.kg-1.h-1 por 20 minutos e os do grupo 3 receberam midazolam na dose de 0,05 mg.kg-1. Os pacientes sedados mantiveram indices 3 ou 4 na escala da sedacao de Ramsay. Foram coletadas amostras de sangue e obtidos tracados de tromboelastografia previamente e apos 30 minutos do tratamento. RESULTADOS: A dexmedetomidina, de forma estatisticamente significativa, aumentou o tempo de reacao (parâmetro R) e diminuiu o indice de coagulacao nos tracados finais em relacao aos iniciais. No entanto, os valores permaneceram dentro dos intervalos considerados normais. Este fenomeno nao foi observado nos demais grupos. CONCLUSOES: A interacao dos mecanismos pro e antiagregantes da dexmedetomidina leva a discreta hipocoagulacao; porem, mantem a coagulacao dentro de parâmetros considerados normais. Os efeitos da dexmedetomidina sobre a coagulacao provavelmente nao ocorrem pela ansiolise, uma vez que a sedacao foi igual ao grupo que recebeu midazolam.