Association between levobupivacaine and pancuronium. Interference in neuromuscular transmission and blockade in rats.

PURPOSE: To evaluate the effects of levobupivacaine on neuromuscular transmission and neuromuscular blockade produced by pancuronium in vitro. METHODS: Thirty rats were distributed into groups (n = 5) according to the drug used alone or in combination: Group I - levobupivacaine (5 µg.mL-1); Group II - pancuronium (2 µg.mL-1); Group III - pancuronium (2 µg.mL-1) + levobupivacaine (5µg.mL-1). The following parameters were evaluated: 1) amplitude of diaphragmatic response to indirect stimulation, before and 60 minutes after the addition of levobupivacaine and pancuronium alone, and after the addition of levobupivacaine combined with pancuronium; 2) membrane potentials (MP) and miniature endplate potentials (MEPP). RESULTS: Levobupivacaine alone did not alter the amplitude of muscle response and MP. In preparations previoulsy exposed to levobupivacaine, the block with pancuronium was significantly denser (90.2 ± 15.2%), showing a significant difference (p=0.031) in comparison to the block produced by pancuronium alone (48.9% ± 9.8%). There was a decrease in the frequency and amplitude of MEPPs. CONCLUSION: Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.

Association between levobupivacaine and pancuronium. Interference in neuromuscular transmission and blockade in rats

ABSTRACT PURPOSE: To evaluate the effects of levobupivacaine on neuromuscular transmission and neuromuscular blockade produced by pancuronium in vitro. METHODS: Thirty rats were distributed into groups (n = 5) according to the drug used alone or in combination: Group I - levobupivacaine (5 µg.mL-1); Group II - pancuronium (2 µg.mL-1); Group III - pancuronium (2 µg.mL-1) + levobupivacaine (5µg.mL-1). The following parameters were evaluated: 1) amplitude of diaphragmatic response to indirect stimulation, before and 60 minutes after the addition of levobupivacaine and pancuronium alone, and after the addition of levobupivacaine combined with pancuronium; 2) membrane potentials (MP) and miniature endplate potentials (MEPP). RESULTS: Levobupivacaine alone did not alter the amplitude of muscle response and MP. In preparations previoulsy exposed to levobupivacaine, the block with pancuronium was significantly denser (90.2 ± 15.2%), showing a significant difference (p=0.031) in comparison to the block produced by pancuronium alone (48.9% ± 9.8%). There was a decrease in the frequency and amplitude of MEPPs. CONCLUSION: Levobupivacaine potentiated the neuromuscular blockade produced by pancuronium, confirming a presynaptic action by a decrease in miniature endplate potentials.

Effect of ropivacaine combined with pancuronium on neuromuscular transmission and effectiveness of neostigmine and 4-aminopyridine for blockade reversal: experimental study / Efeito da associação ropivacaina-pancurônio na transmissão neuromuscular e eficácia da neostigmine e 4-aminopiridina na reversão do bloqueio: estudo experimental / Efecto de la asociación ropivacaína-pancuronio en la transmisión neuromuscular. Eficacia de la neostigmina y 4-aminopiridina en la reversión del bloqueo. Estudio experimental

BACKGROUND AND OBJECTIVES: The local anesthetic effects on neuromuscular junction and its influence on blockade produced by nondepolarizing neuromuscular blockers are still under-investigated; however, this interaction has been described in experimental studies and in humans. The aim of this study was to evaluate in vitro the interaction between ropivacaine and pancuronium, the influence on transmission and neuromuscular blockade, and the effectiveness of neostigmine and 4-aminopyridine to reverse the blockade. METHODS: Rats were divided into groups (n = 5) according to the study drug: ropivacaine (5 µg mL-1); pancuronium (2 µg mL-1); ropivacaine + pancuronium. Neostigmine and 4-aminopyridine were used at concentrations of 2 µg mL-1 and 20 µg mL-1, respectively. The effects of ropivacaine on membrane potential and miniature endplate potential, the amplitude of diaphragm responses before and 60 min after the addition of ropivacaine (degree of neuromuscular blockade with pancuronium and with the association of pancuronium-ropivacaine), and the effectiveness of neostigmine and 4-aminopyridine on neuromuscular block reversal were evaluated. RESULTS: Ropivacaine did not alter the amplitude of muscle response (the membrane potential), but decreased the frequency and amplitude of the miniature endplate potential. Pancuronium blockade was potentiated by ropivacaine, and partially and fully reversed by neostigmine and 4-aminopyridine, respectively. CONCLUSIONS: Ropivacaine increased the neuromuscular block produced by pancuronium. The complete antagonism with 4-aminopyridine suggests presynaptic action of ropivacaine. .

JUSTIFICATIVA E OBJETIVOS: Os efeitos dos anestésicos locais na junção neuromuscular e sua influência no bloqueio produzido por bloqueadores neuromusculares não-despolarizantes é ainda alvo de pouca investigação, no entanto esta interação tem sido descrita em trabalhos experimentais e em humanos. O objetivo deste estudo foi avaliar in vitro, a interação da ropivacaína com o pancurônio, a influência na transmissão e bloqueio neuromuscular e a efetividade da neostigmina e 4-aminopiridina na reversão do bloqueio. MÉTODO: Ratos foram distribuídos em grupos (n = 5) de acordo com o fármaco estudado: ropivacaína (5 µg mL-1); pancurônio (2 µg mL-1); ropivacaína + pancurônio. A neostigmina e a 4-aminopiridina foram usadas nas concentrações de 2 µg mL-1 e 20 µg.mL-1, respectivamente. Avaliou-se: 1) efeitos da ropivacaína sobre o potencial de membrana e potenciais de placa terminal em miniatura; 2) a amplitude das respostas do diafragma antes e 60 minutos após a adição da ropivacaína; o grau de bloqueio neuromuscular com o pancurônio e com a associação pancurônio - ropivacaína; 3) a efetividade da neostigmina e 4-aminopiridina na reversão do bloqueio neuromuscular. RESULTADOS: A ropivacaína não alterou a amplitude das respostas musculares, os potenciais de membrana, mas diminuiu a frequência e a amplitude dos potenciais de placa terminal em miniatura. O bloqueio produzido pelo pancurônio foi potencializado pela ropivacaína, e parcial e totalmente revertido pela neostigmina e 4-aminopiridina, respectivamente. CONCLUSÕES: A ropivacaína potencializou o bloqueio neuromuscular produzido pelo pancurônio. O antagonismo completo com a 4-aminopiridina sugere ação pré-sináptica da ropivacaína. .

JUSTIFICACIÓN Y OBJETIVOS: Los efectos de los anestésicos locales en la unión neuromuscular y su influencia en el bloqueo producido por bloqueantes neuromusculares no-despolarizantes todavía son poco investigados, sin embargo, esta interacción ha sido descrita en trabajos experimentales y en seres humanos. El objetivo de este estudio fue evaluar in vitro la interacción de la ropivacaína con el pancuronio, la influencia en la transmisión y bloqueo neuromuscular y la efectividad de la neostigmina y 4-aminopiridina en la reversión del bloqueo. MÉTODO: Unos ratones fueron distribuidos en grupos (n = 5) de acuerdo con el fármaco estudiado: ropivacaína (5 µg/ml-1); pancuronio (2 µg/ml-1); ropivacaína + pancuronio. La neostigmina y la 4-aminopiridina fueron usadas en concentraciones de 2 µg/ml-1 y 20 µg/ml-1, respectivamente. Evaluamos: 1) efectos de la ropivacaína sobre el potencial de membrana y potenciales de placa terminal en miniatura; 2) la amplitud de las respuestas del diafragma antes y 60 min después de la adición de la ropivacaína; el grado de bloqueo neuromuscular con el pancuronio y con la asociación pancuronio-ropivacaína; 3) la efectividad de la neostigmina y 4-aminopiridina en la reversión del bloqueo neuromuscular. RESULTADOS: La ropivacaína no alteró la amplitud de las respuestas musculares, los potenciales de membrana, pero disminuyó la frecuencia y la amplitud de los potenciales de placa terminal en miniatura. El bloqueo producido por el pancuronio fue potenciado por la ropivacaína, y parcial y totalmente revertido por la neostigmina y 4-aminopiridina, respectivamente. CONCLUSIONES: La ropivacaína potenció el bloqueo neuromuscular producido por el pancuronio. El antagonismo completo con la 4-aminopiridina muestra una acción presináptica de la ropivacaína. .

[Effect of ropivacaine combined with pancuronium on neuromuscular transmission and effectiveness of neostigmine and 4-aminopyridine for blockade reversal: experimental study]. / Efeito da associação ropivacaina-pancurônio na transmissão neuromuscular e eficácia da neostigmine e 4-aminopiridina na reversão do bloqueio: estudo experimental.

BACKGROUND AND OBJECTIVES: The local anesthetic effects on neuromuscular junction and its influence on blockade produced by nondepolarizing neuromuscular blockers are still under-investigated; however, this interaction has been described in experimental studies and in humans. The aim of this study was to evaluate in vitro the interaction between ropivacaine and pancuronium, the influence on transmission and neuromuscular blockade, and the effectiveness of neostigmine and 4-aminopyridine to reverse the blockade. METHODS: Rats were divided into groups (n=5) according to the study drug: ropivacaine (5µgmL(-1)); pancuronium (2µg.mL(-1)); ropivacaine+pancuronium. Neostigmine and 4-aminopyridine were used at concentrations of 2µgmL(-1) and 20µgmL(-1), respectively. The effects of ropivacaine on membrane potential and miniature end-plate potential, the amplitude of diaphragm responses before and 60minutes after the addition of ropivacaine (degree of neuromuscular blockade with pancuronium and with the association of pancuronium-ropivacaine), and the effectiveness of neostigmine and 4-aminopyridine on neuromuscular block reversal were evaluated. RESULTS: Ropivacaine did not alter the amplitude of muscle response (the membrane potential), but decreased the frequency and amplitude of the miniature end-plate potential. Pancuronium blockade was potentiated by ropivacaine, and partially and fully reversed by neostigmine and 4-aminopyridine, respectively. CONCLUSIONS: Ropivacaine increased the neuromuscular block produced by pancuronium. The complete antagonism with 4-aminopyridine suggests presynaptic action of ropivacaine.

Effect of 50% enantiomeric excess bupivacaine mixture combined with pancuronium on neuromuscular transmission in rat phrenic nerve-diaphragm preparation; a pilot study.

BACKGROUND AND AIMS: Local anaesthetics are drugs that are widely used in clinical practice. However, the effects of these drugs on the neuromuscular junction and their influence on the blockade produced by non-depolarising neuromuscular blocking drugs are still under investigation. The aim of this study was to evaluate, in vitro, the influence of a 50% enantiomeric excess bupivacaine mixture on neuromuscular transmission and neuromuscular block produced by pancuronium. METHODS: Rats were distributed into three groups (n = 5) according to the drug studied namely, 50% enantiomeric excess bupivacaine mixture (5 µg/mL); pancuronium (2 µg/mL); 50% enantiomeric excess bupivacaine mixture + pancuronium. The following parameters were evaluated: (1) Effects of a 50% enantiomeric excess bupivacaine mixture on membrane potential (MP) and miniature endplate potentials (MEPPs); (2) amplitude of diaphragmatic response before and 60 min after the addition of a 50% enantiomeric excess bupivacaine mixture; the degree of neuromuscular block with pancuronium and pancuronium combined with a 50% enantiomeric excess bupivacaine mixture. RESULTS: A 50% enantiomeric excess bupivacaine mixture did not alter the amplitude of muscle response (MP) but decreased the frequency and amplitude of MEPP. The block produced by pancuronium was potentiated by a 50% enantiomeric excess bupivacaine mixture. CONCLUSION: A 50% enantiomeric excess bupivacaine mixture used alone did not affect neuromuscular transmission, but potentiated the neuromuscular block produced by pancuronium. No action was shown on the muscle fibre, and alterations on MEPPs demonstrated a presynaptic action.

Evidence of presynaptic and postsynaptic action of local anesthetics in rats.

PURPOSE: To assess the probable actions of ropivacaine, 50% enantiomeric excess bupivacaine mixture (S75-R25) and levobupivacaine on neuromuscular transmission in vitro. METHODS: Thirty rats were distributed into groups (n=5) according to the drug used: ropivacaine, bupivacaine (S75-R25) and levobupivacaine. The concentration used for the three local anesthetics (LA) was 5 µg.mL. (-1)The following parameters were evaluated: 1) LA effects on membrane potential (MP) and miniature end plate potential (MEPP). A chick biventer cervicis preparation was also used to evaluate LA effects on the contracture response to acetylcholine. RESULTS: LA did not alter MP values and decreased the frequency and amplitude of MEPP. In a chick biventer cervicis preparation, bupivacaine (S75-R25) and levobupivacaine decreased the contracture response to acetylcholine with statistical significance, in comparison to ropivacaine. CONCLUSIONS: In the concentrations used, levobupivacaine and bupivacaine (S75-R25) exhibited presynaptic and postsynaptic actions evidenced by alterations in miniature end plate potentials and contracture response to acetylcholine. Ropivacaine only had a presynaptic action.

Evidence of presynaptic and postsynaptic action of local anesthetics in rats

PURPOSE: To assess the probable actions of ropivacaine, 50% enantiomeric excess bupivacaine mixture (S75-R25) and levobupivacaine on neuromuscular transmission in vitro. METHODS: Thirty rats were distributed into groups (n=5) according to the drug used: ropivacaine, bupivacaine (S75-R25) and levobupivacaine. The concentration used for the three local anesthetics (LA) was 5 µg.mL.-1The following parameters were evaluated: 1) LA effects on membrane potential (MP) and miniature end plate potential (MEPP). A chick biventer cervicis preparation was also used to evaluate LA effects on the contracture response to acetylcholine. RESULTS: LA did not alter MP values and decreased the frequency and amplitude of MEPP. In a chick biventer cervicis preparation, bupivacaine (S75-R25) and levobupivacaine decreased the contracture response to acetylcholine with statistical significance, in comparison to ropivacaine. CONCLUSIONS: In the concentrations used, levobupivacaine and bupivacaine (S75-R25) exhibited presynaptic and postsynaptic actions evidenced by alterations in miniature end plate potentials and contracture response to acetylcholine. Ropivacaine only had a presynaptic action.

Influência dos Hipnóticos no bloqueio neuromuscular produzido pelo cisatracúrio: emprego da aceleromiografia / Influence of hypnotics on cisatracurium-induced neuromuscular block: use of acceleromyograhpy / Influencia de los hipnóticos en el bloqueo neuromuscular producido por el cisatracurio: uso de la aceleromiografía

JUSTIFICATIVA E OBJETIVOS: Os efeitos farmacodinâmicos dos bloqueadores neuromusculares (BNM) podem ser influenciados por diferentes drogas, entre elas os hipnóticos. O objetivo deste estudo foi avaliar a influência do propofol e do etomidato sobre o bloqueio neuromuscular produzido pelo cisatracúrio. MÉTODO: Foram incluídos 60 pacientes, ASA I e II, submetidos a cirurgias eletivas sob anestesia geral, distribuídos aleatoriamente em dois grupos de acordo com o hipnótico empregado: GI (propofol) e GII (etomidato). As pacientes receberam midazolam (0,1 mg.kg-1) por via muscular como medicação pré-anestésica, a indução foi com propofol (2,5 mg.kg-1) ou etomidato (0,3 mg.kg-1) precedido de fentanil (250 µg) e seguido de cisatracúrio (0,1 mg.kg-1). Os pacientes foram ventilados com oxigênio a 100% até a obtenção de redução de 95% ou mais na amplitude da resposta do adutor do polegar, quando foi feita a laringoscopia e a intubação traqueal. A função neuromuscular foi monitorizada com aceleromiografia. Avaliaram-se o início de ação do cisatracúrio, as condições de intubação traqueal e as repercussões hemodinâmicas. RESULTADOS: Os tempos médios e os desvios padrão para o início de ação do cisatracúrio foram: GI (86,6 ± 14,3") e GII (116,9 ± 11,6"), com diferença significativa (p < 0,0001). As condições de intubação traqueal foram aceitáveis em 100% dos pacientes do GI e em 53,3% no GII (p < 0,0001). CONCLUSÕES: A instalação do bloqueio neuromuscular com o cisatracúrio foi mais rápida e as condições de intubação traqueal foram melhores nos pacientes que receberam propofol em relação ao grupo que recebeu etomidato, sem repercussões hemodinâmicas.

BACKGROUND AND OBJECTIVE: Different drugs, including hypnotics, may influence the pharmacodynamic effects of neuromuscular blockers (NMB). The aim of this study was to evaluate the influence of propofol and etomidate on cisatracurium-induced neuromuscular blockade. METHOD: We included 60 patients, ASA I and II, undergoing elective surgery under general anesthesia in the study and randomly allocated them into two groups, according to their hypnotic drug: GI (propofol) and GII (etomidate). Patients received intramuscular (IM) midazolam (0.1 mg.kg-1) as premedication and we performed induction with propofol (2.5 mg.kg-1) or etomidate (0.3 mg.kg-1), preceded by fentanyl (250 mg) and followed by cisatracurium (0.1 mg.kg-1). The patients were ventilated with 100% oxygen until obtaining a reduction of 95% or more in the adductor pollicis response amplitude, with subsequent laryngoscopy and tracheal intubation. Neuromuscular function was monitored by acceleromyograhpy. We evaluated the onset of action of cisatracurium, tracheal intubation conditions, and hemodynamic repercussions. RESULTS: The mean time and standard deviations of cisatracurium onset were: GI (86.6 ± 14.3 s) and GII (116.9 ± 11.6 s), with a significant difference (p < 0, 0001). Intubation conditions were acceptable in 100% of GI and 53.3% of GII patients (p < 0.0001). CONCLUSION: Induction of neuromuscular blockade with cisatracurium was faster, with better intubation conditions in patients receiving propofol compared to those receiving etomidate, without hemodynamic repercussions.

JUSTIFICATIVA Y OBJETIVOS: Los efectos farmacodinámicos de los bloqueantes neuromusculares (BNM) pueden estar influenciados por diferentes fármacos, entre ellos los hipnóticos. El objetivo de este estudio, fue evaluar la influencia del propofol y del etomidato sobre el bloqueo neuromuscular producido por el cisatracurio. MÉTODO: Se incluyeron en el estudio 60 pacientes, con ASA I y II, sometidos a cirugías electivas bajo anestesia general, distribuidos aleatoriamente en dos grupos de acuerdo con el hipnótico usado: GI (propofol) y GII (etomidato). Las pacientes recibieron midazolam (0,1 mg.kg-1) por vía muscular como medicación preanestésica, la inducción fue con propofol (2,5 mg.kg-1) o etomidato (0,3 mg.kg-1) precedido de fentanilo (250 µg) y seguido de cisatracurio (0,1 mg.kg-1). Los pacientes fueron ventilados con oxígeno al 100% hasta la obtención de la reducción de un 95% o más en la amplitud de la respuesta del aductor del pulgar cuando se hizo la laringoscopia y la intubación traqueal. La función neuromuscular fue monitorizada con aceleromiografía. Se evaluaron el inicio de acción del cisatracurio, las condiciones de intubación traqueal y las repercusiones hemodinámicas. RESULTADOS: Los tiempos promedios y las desviaciones estándar para el inicio de acción del cisatracurio fueron: GI (86,6 ± 14,3") y GII (116,9 ± 11,6"), con una diferencia significativa (p < 0,0001). Las condiciones de intubación traqueal fueron aceptables en un 100% de los pacientes del GI y en 53,3% en el GII (p < 0,0001). CONCLUSIONES: La instalación del bloqueo neuromuscular con el cisatracurio fue más rápida y las condiciones de intubación traqueal fueron mejores en los pacientes que recibieron propofol con relación al grupo que recibió etomidato, sin repercusiones hemodinámicas.

Anaphylaxis during renal transplantation of live donor graft in a child with latex allergy: case report.

BACKGROUND AND OBJECTIVES: Latex allergy is becoming increasingly more frequent, affecting patients and health care professionals. The objective of this report was to present the case of a child with allergy to latex, who developed anaphylaxis during anesthesia for renal transplantation, and emphasize some of the multidisciplinary conducts used to decrease the risk of anaphylactic shock after graft reperfusion. CASE REPORT: A male child, 5 years and 10 months old, P3 by the ASA classification, with a history of allergy to latex diagnosed after contact with balloons and confirmed by Rast test specific for latex and Prick test, underwent renal transplantation of a live donor graft for end-stage renal disease secondary to urologic malformation. The protocols for patients with Latex Allergy adopted by the Anesthesiology and Nursing Departments of the Hospital das Clínicas da UNICAMP were observed to avoid exposure of the child to latex. They started the day before the surgery by cleaning the operating rooms and substituting of all medical-hospital products by latex-free material. The equipment and materials used during the procedure were latex-free according to a technical report provided by the manufacturers. The surgery was done under general anesthesia and controlled mechanical ventilation. At the end of the surgery, the patient required blood transfusion, which was administered by a pressurizer; he developed cutaneous rash and the blood transfusion was discontinued, hydrocortisone was administered, and the infusion of crystalloids was increased. The child had an immediate and satisfactory response to the treatment. CONCLUSIONS: Latex allergy has become a public health problem and the knowledge of specific therapeutic conducts allows immediate treatment and decreases patient risks.

Reação anafilática durante transplante renal intervivos em criança alérgica ao látex: relato de caso / Anaphylaxis during renal transplantation of live donor graft in a child with latex allergy: case report / Reacción anafiláctica durante transplante renal intervivos en niño alérgico al látex: relato de caso

JUSTIFICATIVA E OBJETIVOS: A alergia ao látex vem se tornando frequente, atingindo pacientes e profissionais de saúde. O objetivo deste relato foi apresentar um caso de criança alérgica ao látex que desenvolveu crise anafilática durante anestesia para transplante renal e destacar algumas condutas multiprofissionais empregadas para diminuir o risco de choque anafilático após a reperfusão do transplante. RELATO DO CASO: Criança do sexo masculino, com 5 anos e 10 meses, P3 pela classificação da ASA, com história de alergia ao látex, diagnosticada após contato com bexigas de festa e confirmada por testes Rast específico para o látex e Prick teste, foi submetida a transplante renal intervivos, por insuficiência renal terminal em consequência de malformação urológica. Os cuidados para evitar a exposição da criança ao látex seguiram os protocolos para paciente alérgico ao látex, adotados pelo Serviço de Anestesia e de Enfermagem do Hospital das Clínicas da UNICAMP. Foram iniciados na véspera da operação com a limpeza terminal das salas cirúrgicas e a substituição de todos os produtos médico-hospitalares por produtos isentos de látex. Os equipamentos e materiais utilizados durante o procedimento possuíam laudo técnico de isenção completa de látex, fornecido pelo fabricante. A operação foi realizada sob anestesia geral com ventilação controlada mecânica. Ao final da operação necessitou de transfusão de concentrado de hemácias administrado com auxílio de pressurizador, apresentando rash cutâneo, cessou-se a transfusão, administrou-se hidrocortisona e aumentou-se a infusão de cristaloides. A resposta ao tratamento foi satisfatória e imediata. CONCLUSÕES: A alergia ao látex tornou-se um problema de saúde pública e o conhecimento de condutas terapêuticas específicas possibilita o pronto atendimento e menor risco para os pacientes.

BACKGROUND AND OBJECTIVES: Latex allergy is becoming increasingly more frequent, affecting patients and health care professionals. The objective of this report was to present the case of a child with allergy to latex, who developed anaphylaxis during anesthesia for renal transplantation, and emphasize some of the multidisciplinary conducts used to decrease the risk of anaphylactic shock after graft reperfusion. CASE REPORT: A male child, 5 years and 10 months old, P3 by the ASA classification, with a history of allergy to latex diagnosed after contact with balloons and confirmed by Rast test specific for latex and Prick test, underwent renal transplantation of a live donor graft for end-stage renal disease secondary to urologic malformation. The protocols for patients with Latex Allergy adopted by the Anesthesiology and Nursing Departments of the Hospital das Clínicas da UNICAMP were observed to avoid exposure of the child to latex. They started the day before the surgery by cleaning the operating rooms and substituting of all medical-hospital products by latex-free material. The equipment and materials used during the procedure were latex-free according to a technical report provided by the manufacturers. The surgery was done under general anesthesia and controlled mechanical ventilation. At the end of the surgery, the patient required blood transfusion, which was administered by a pressurizer; he developed cutaneous rash and the blood transfusion was discontinued, hydrocortisone was administered, and the infusion of crystalloids was increased. The child had an immediate and satisfactory response to the treatment. CONCLUSIONS: Latex allergy has become a public health problem and the knowledge of specific therapeutic conducts allows immediate treatment and decreases patient risks.

JUSTIFICATIVA Y OBJETIVOS: La alergia al látex ha venido alcanzando a menudo a pacientes y a profesionales de la salud. El objetivo de este relato, fue presentar un caso de niño alérgico al látex que debutó con una crisis anafiláctica durante la anestesia para transplante renal, y destacar algunas conductas multiprofesionales usadas para reducir el riesgo de choque anafiláctico después de la reperfusión del transplante. RELATO DEL CASO: Niño del sexo masculino, con 5 años y 10 meses, P3 por la clasificación de la ASA, con historial de alergia al látex diagnosticado después de haber tenido contacto con globos de fiesta y confirmado por tests Rast específico para el látex y Prick test. Se le sometió a transplante renal intervivos, por insuficiencia renal terminal, como consecuencia de una malformación urológica. Los cuidados para evitar la exposición del niño al látex, secundaron los Protocolos para paciente Alérgico al Látex, adoptados por el Servicio de Anestesia y de Enfermería del Hospital de las Clínicas de la UNICAMP. Esos cuidados fueron iniciados en la víspera de la operación, con la limpieza terminal de las salas quirúrgicas, y el reemplazo de todos los productos médico hospitalarios, por productos exentos de látex. Los equipos y materiales utilizados durante el procedimiento poseían un laudo técnico, de exención completa de látex, suministrado por el fabricante. La operación fue realizada bajo anestesia general con ventilación controlada mecánica. Al final de la operación, necesitó una transfusión de concentrado de hematíes, administrado con la ayuda de presurizador, presentando rash cutáneo, se suspendió la transfusión, se le administró hidrocortisona y se le aumentó la infusión de cristaloides. La respuesta al tratamiento fue satisfactoria e inmediata. CONCLUSIONES: La alergia al látex se convirtió en un problema de salud pública y el conocimiento de conductas terapéuticas específicas, posibilita la rápida atención y un menor...

Neuromuscular and cardiovascular effects of pipecuronium. A comparative study between different doses.

BACKGROUND AND OBJECTIVES: Pipecuronium is a non-depolarizing neuromuscular blocker with similar properties to pancuronium, but without cardiovascular effects. Neuromuscular effects, conditions of tracheal intubation, and hemodynamic repercussions of two different doses of pipecuronium were evaluated. METHOD: Patients were divided into two groups according to the dose of pipecuronium: Group I (0.04 mg x kg(-1)) and Group II (0.05 mg x kg(-1)). Intramuscular midazolam (0.1 mg x kg(-1)) was administered 30 minutes before the surgery. Propofol (2.5 mg x kg(-1)), preceded by fentanyl (5 microg x kg(-1)) and pipecuronium (0.04 and 0.05 mg x kg(-1) for Groups I and II, respectively), was administered for anesthetic induction. Patients were ventilated with 100% oxygen via a face mask until a 75% reduction in the amplitude of the response to an isolated stimulus (1 Hz) is achieved, at which time laryngoscopy and intubation were carried out. Anesthetic maintenance was achieved with isoflurane (0.5 to 1%) with a mixture of 50% O2 and N2O. Mechanical ventilation was used to maintain P(ET)CO2 between 32 and 36 mmHg. The pharmacodynamics of pipecuronium was evaluated by acceleromyography. RESULTS: Mean times and standard deviation for the onset of action, clinical duration (T1(25%)), and recovery index (T1(25-75%)) were: Group I (122.10 +/- 4.18 sec, 49.63 +/- 9.54 min, and 48.21 +/- 6.72 min), and Group II (95.78 +/- 8.91 sec, 64.84 +/- 13.13 min, and 48.52 +/- 4.95 min). Onset of action, clinical duration, and conditions of tracheal intubation were significantly different for both groups. CONCLUSIONS: Pipecuronium at a dose of 0.05 mg x kg(-1) can be used in prolonged procedures in which cardiovascular changes should be avoided.

Efeitos neuromusculares e cardiovasculares do pipecurônio: estudo comparativo entre diferentes doses / Efectos neuromusculares y cardiovasculares del pipecuronio: estudio comparativo entre diferentes dosis / Neuromuscular and cardiovascular effects of pipecuronium: a comparative study between different dose

JUSTIFICATIVA E OBJETIVOS: O pipecurônio é um bloqueador neuromuscular não-despolarizante, com propriedades similares as do pancurônio, mas desprovido de efeitos cardiovasculares. Foram avaliados os efeitos neuromusculares, as condições de intubação traqueal e as repercussões hemodinâmicas de duas diferentes doses de pipecurônio. MÉTODO: Pacientes foram distribuídos em dois grupos de acordo com a dose de pipecurônio: Grupo I (0,04 mg.kg-1) e Grupo II (0,05 mg.kg-1). A medicação pré-anestésica consistiu em midazolam (0,1 mg.kg-1) por via muscular, 30 minutos antes da operação. A indução anestésica foi obtida com propofol (2,5 mg.kg-1) precedido de fentanil (5 µg.kg-1) e pipecurônio nas doses de 0,04 e 0,05 mg.kg-1 para os Grupos I e II, respectivamente. Os pacientes foram ventilados com O2 a 100 por cento sob máscara até a redução de 75 por cento da amplitude da resposta a estímulo isolado (1 Hz), quando foram realizadas a laringoscopia e intubação traqueal. O isoflurano (0,5 a 1 por cento) em mistura de O2 e N(2)0 a 50 por cento para a manutenção da anestesia, foi introduzido logo após a intubação traqueal. Os pacientes foram ventilados mecanicamente para manter P ET CO2 entre 32 e 36 mmHg. A farmacodinâmica do pipecurônio foi avaliada por aceleromiografia. RESULTADOS: Os tempos médios e desvios-padrão para o início de ação, duração clínica (T1(25 por cento)) e índice de recuperação (T1(25-75 por cento)) foram: Grupo I (122,10 ± 4,18 s, 49,63 ± 9,54 min e 48,21 ± 6,72 min) e Grupo II (95,78 ± 8,91 s, 64,84 ± 13,13 min e 48,52 ± 4,95 min). O início de ação, a duração clínica e as condições de intubação traqueal foram significativamente diferentes entre os grupos. CONCLUSÕES: O pipecurônio na dose 0,05 mg.kg-1 pode ser usado em procedimentos de longa duração, nos quais é desejável evitar alterações cardiocirculatórias.

BACKGROUND AND OBJECTIVES: Pipecuronium is a non-depolarizing neuromuscular blocker with similar properties to pancuronium, but without cardiovascular effects. Neuromuscular effects, conditions of tracheal intubation, and hemodynamic repercussions of two different doses of pipecuronium were evaluated. METHOD: Patients were divided into two groups according to the dose of pipecuronium: Group I (0.04 mg.kg-1) and Group II (0.05 mg.kg-1). Intramuscular midazolam (0.1 mg.kg-1) was administered 30 minutes before the surgery. Propofol (2.5 mg.kg-1), preceded by fentanyl (5 µg.kg-1) and pipecuronium (0.04 and 0.05 mg.kg-1 for Groups I and II, respectively), was administered for anesthetic induction. Patients were ventilated with 100 percent oxygen via a face mask until a 75 percent reduction in the amplitude of the response to an isolated stimulus (1 Hz) is achieved, at which time laryngoscopy and intubation were carried out. Anesthetic maintenance was achieved with isoflurane (0.5 to 1 percent) with a mixture of 50 percent O2 and N2O. Mechanical ventilation was used to maintain P ET CO2 between 32 and 36 mmHg. The pharmacodynamics of pipecuronium was evaluated by acceleromyography. RESULTS: Mean times and standard deviation for the onset of action, clinical duration (T1(25 percent)), and recovery index (T1(25-75 percent)) were: Group I (122.10 ± 4.18 sec, 49.63 ± 9.54 min, and 48.21 ± 6.72 min), and Group II (95.78 ± 8.91 sec, 64.84 ± 13.13 min, and 48.52 ± 4.95 min). Onset of action, clinical duration, and conditions of tracheal intubation were significantly different for both groups. CONCLUSIONS: Pipecuronium at a dose of 0.05 mg.kg-1 can be used in prolonged procedures in which cardiovascular changes should be avoided.

JUSTIFICATIVA Y OBJETIVOS: El pipecuronio es un bloqueador neuromuscular no despolarizador, con propiedades similares a las del pancuronio, pero desprovisto de efectos cardiovasculares. Se evaluaron los efectos neuromusculares, condiciones de intubación traqueal y las repercusiones hemodinámicas de de los diferentes dosis de pipecuronio. MÉTODO: Los pacientes fueron distribuidos en de los grupos de acuerdo a la dosis de pipecuronio: Grupo I (0,04 mg.kg-1) y Grupo II (0,05 mg.kg-1). La medicación preanestésica consistió en midazolam (0,1 mg.kg-1) por vía muscular, 30 minutos antes de la operación. La inducción anestésica se obtuvo con propofol (2,5 mg.kg-1) precedido del fentanil (5 µg.kg-1) y del pipecuronio en las dosis de 0,04 y 0,05 mg.kg-1 para los Grupos I y II, respectivamente. Los pacientes se ventilaron con O2 a 100 por ciento bajo máscara hasta la reducción de un 75 por ciento de la amplitud de la respuesta al estímulo aislado (1 Hz), cuando fueron realizadas la laringoscopía y la intubación traqueal. El isoflurano (0,5 a 1 por ciento) en mezcla de O2 y N(2)0 a un 50 por ciento para el mantenimiento de la anestesia, fue introducido a continuación de la intubación traqueal. Los pacientes fueron ventilados mecánicamente para mantener el P ET CO2 entre 32 y 36 mmHg. La farmacodinámica del pipecuronio se evaluó por aceleromiografía. RESULTADOS: Los tiempos promedios y desviaciones estándar para el inicio de acción, duración clínica (T1(25 por ciento)) e índice de recuperación (T1(25-75 por ciento)) fueron los siguientes: Grupo I (122,10 ± 4,18 seg, 49,63 ± 9,54 min y 48,21 ± 6,72 min) y Grupo II (95,78 ± 8,91 seg, 64,84 ± 13,13 min y 48,52 ± 4,95 min). El inicio de acción, la duración clínica y las condiciones de intubación traqueal fueron significativamente diferentes entre los grupos. CONCLUSIONES: El pipecuronio, en la dosis 0,05 mg.kg-1 puede ser usado en procedimientos de larga duración donde se desee evitar alteraciones ca...

Influence of stimulus frequency on blockade induced by pancuronium and rocuronium: study on rats phrenic nerve-diaphragm preparation

PURPOSE: To evaluate the influence of two stimulation frequencies on the installation of neuromuscular blockade produced by pancuronium and rocuronium on the rat diaphragm. METHODS: Diaphragms were submitted to an indirect frequency stimulation of 0.1 and 1Hz (Groups I and II, respectively). Subgroups were formed (n=5) according to the neuromuscular blocker employed (pancuronium-2µg/ml and rocuronium-4µg/ml). The twitch height depression was evaluated at 5, 15 and 30 minutes after adding the neuromuscular blocker. RESULTS: The decrease in twitch height was greater (p<0.01) with a frequency of 1Hz at all time periods studied both in preparations that are blocked with pancuronium and in those that are blocked with rocuronium. CONCLUSION: The frequency of stimulation interferes significantly with the installation of neuromuscular blockade produced by pancuronium and rocuronium, since the reduction in amplitude of the rat diaphragm response was greater for 1Hz frequencies, at all periods studied.

OBJETIVO: Avaliar a influência de duas freqüências de estimulação na instalação do bloqueio neuromuscular induzido por pancurônio e rocurônio em diafragma de ratos. MÉTODOS: Os diafragmas foram submetidos a uma freqüência de estimulação indireta de 0.1 e 1Hz (Grupos I e II, respectivamente). Os animais foram divididos em subgrupos (n=5) de acordo com o bloqueador neuromuscular a ser utilizado (pancurônio-2µg/mL e rocurônio-4µg/mL). A amplitude das respostas musculares foi avaliada 5, 15 e 30 minutos após a adição do bloqueador neuromuscular à preparação. RESULTS: A redução na intensidade da contração foi maior (p<0.01) com a freqüência de 1Hz em todos os tempos avaliados para as preparações contendo pancurônio e rocurônio CONCLUSION: A freqüência de estímulo interfere significativamente na instalação do bloquio neuromuscular produzido por pancurônio e rocurônio, uma vez que a redução na amplitude da resposta do diafragma foi maior para a freqüência de 1Hz em todos os períodos estudados.

Plastia tricúspide utilizando anuloplastia baseada na proporção entre os segmentos do anel da valva tricúspide normal / Tricuspid valve repair using the proportion between segments of normal tricuspid annulus as a parameter for annuloplasty

OBJETIVO: Determinar a proporção existente entre os segmentos do anel da valva tricúspide (VT) normal e aplicála na realização da anuloplastia tricúspidea "in vitro" e "in vivo". MÉTODOS: Imagens digitais do anel tricuspídeo de 30 corações de cadáveres humanos, sem formolização e sem insuficiência tricúspide (IT), foram analisadas e a proporção entre os segmentos ântero-posterior e septal foi determinada. Esta proporção foi utilizada na anuloplastia da VT com anel maleável de pericárdio bovino (PB), em 15 corações de cadáveres com IT e dilatação do anel valvar. A mesma proporção e técnica foi utilizada na realização de anuloplastia tricuspídea, em 11 pacientes com IT funcional, entre os quais, sete possuíam IT importante e quatro, moderada; cinco apresentavam insuficiência cardíaca (IC) classe IV (NYHA) e seis, classe III. RESULTADOS: Nas valvas continentes de cadáveres, a razão média entre o segmento ântero-posterior e septal foi 2,43±0,212. O tamanho médio dos anéis maleáveis PB utilizados "in vitro" foi 71,5±5,2mm e mediana 70mm. Todas as valvas ficaram continentes após a anuloplastia tricuspídea "in vitro". O tamanho médio do anel maleável PB utilizado "in vivo" foi 73,4±6,5mm e mediana 72mm. Ocorreu um (9,1 por cento) óbito. Na avaliação com 6 meses de pós-operatório, sete pacientes não possuíam IT e três possuíam IT leve; seis pacientes apresentavam IC classe I, três, classe II e um, classe III. CONCLUSÃO: O uso da proporção de 2,43:1 entre os segmentos ântero-posterior e septal, como um parâmetro na anuloplastia da VT, utilizando anel maleável de pericárdio bovino, demonstrou resultados iniciais favoráveis.

OBJECTIVE: To determine the proportion between the segments of the normal human tricuspid valve (TV) annulus and its use as a parameter for ring annuloplasty "in vitro" and "in vivo". METHODS: Digital images of the tricuspid ring of 30 human cadaveric hearts, without fixation and without tricuspid regurgitation (TR), were analyzed and the proportion between the antero-posterior and septal segments was determined. This proportion was used for TV annuloplasty with bovine pericardium (BP) flexible rings on 15 hearts from adult cadavers with TR and ring dilatation. The same proportion and technique were used for TV repair on 11 patients with functional TR. Preoperatively, seven patients had severe and four moderate TR; five patients were class IV and six class III (NYHA). RESULTS:The mean ratio between the antero-posterior and septal segments was 2.43±0.212 in the 30 hearts without TR. The mean size of the BP flexible ring used for "in vitro" surgical procedure was 71.5±5.2 mm, median 70 mm, and there was no TR after that in all 15 hearts. The mean size of the orthesis used on the patients was 73.4±6.5 mm, median 72 mm. There was 1 hospital death. Six months after surgery, 7 patients had no TR and 3 had mild TR; 6 patients were in NYHA class I, 3 in class II and 1 in class III. CONCLUSION: The use of the ratio 2.43:1 between the anterior-posterior and septal segments as a parameter in tricuspid valve annuloplasty with a bovine pericardium flexible ring leads to satisfactory results.

Endovenous laser treatment for varicose veins in patients with active ulcers: measurement of intravenous and perivenous temperatures during the procedure.

BACKGROUND: Conventional saphenous vein stripping is difficult to be indicated for the treatment of varicose veins in patients classified as CEAP C4, C5, or C6. OBJECTIVE: This study was developed to evaluate treatment results for varicose veins with active ulcers using endovenous laser (EVL), compared to a group undergoing clinical treatment, during 1 year. PATIENTS AND METHOD: Fifty-two patients presenting with varicose veins with active ulcers for more than 1 year were divided for treatment into two randomized groups: Group 1, clinical treatment, composed of 25 subjects, was submitted to elastic or inelastic compression therapy; Group 2, EVL treatment, composed of 27 subjects, was submitted to great and or small saphenous vein ablation with a 980-nm diode EVL, plus the clinical treatment. Intravenous and perivenous temperatures were measured continuously during the EVL treatment. All patients were followed for 12 months and studied with ultrasound at the beginning and end of the study. The ulcers' areas were evaluated initially and at every 3 months. RESULTS: In 12 months, 81.5% of the wounds in patients in Group 2 and only 24% in patients in Group 1 had healed. Ulcer recurrence rate was 44.4% in Group 1. The mean wound area in Group 1 decreased from 17.48 to 12.76 cm(2) at the end of the year. In Group 2, the wound area decreased from 22.26 to 2.7 cm(2) (p=.0037). Mean intravenous and perivenous temperatures of 79.3 and 43.0 degrees C were recorded. CONCLUSION: The treatment for varicose veins with EVL is safe in patients with active ulcers. Wounds healed faster than in patients undergoing clinical treatment alone during a 1-year period. There was no ulcer recurrence in patients treated with EVL.

Tricuspid valve repair using the proportion between segments of normal tricuspid annulus as a parameter for annuloplasty.

OBJECTIVE: To determine the proportion between the segments of the normal human tricuspid valve (TV) annulus and its use as a parameter for ring annuloplasty "in vitro" and "in vivo". METHODS: Digital images of the tricuspid ring of 30 human cadaveric hearts, without fixation and without tricuspid regurgitation (TR), were analyzed and the proportion between the antero-posterior and septal segments was determined. This proportion was used for TV annuloplasty with bovine pericardium (BP) flexible rings on 15 hearts from adult cadavers with TR and ring dilatation. The same proportion and technique were used for TV repair on 11 patients with functional TR. Preoperatively, seven patients had severe and four moderate TR; five patients were class IV and six class III (NYHA). RESULTS: The mean ratio between the antero-posterior and septal segments was 2.43+/-0.212 in the 30 hearts without TR. The mean size of the BP flexible ring used for "in vitro" surgical procedure was 71.5+/-5.2 mm, median 70 mm, and there was no TR after that in all 15 hearts. The mean size of the orthesis used on the patients was 73.4+/-6.5 mm, median 72 mm. There was 1 hospital death. Six months after surgery, 7 patients had no TR and 3 had mild TR; 6 patients were in NYHA class I, 3 in class II and 1 in class III. CONCLUSION: The use of the ratio 2.43:1 between the anterior-posterior and septal segments as a parameter in tricuspid valve annuloplasty with a bovine pericardium flexible ring leads to satisfactory results.

Influence of stimulus frequency on blockade induced by pancuronium and rocuronium: study on rats phrenic nerve-diaphragm preparation.

PURPOSE: To evaluate the influence of two stimulation frequencies on the installation of neuromuscular blockade produced by pancuronium and rocuronium on the rat diaphragm. METHODS: Diaphragms were submitted to an indirect frequency stimulation of 0.1 and 1 Hz (Groups I and II, respectively). Subgroups were formed (n=5) according to the neuromuscular blocker employed (pancuronium-2 microg/ml and rocuronium-4 microg/ml). The twitch height depression was evaluated at 5, 15 and 30 minutes after adding the neuromuscular blocker. RESULTS: The decrease in twitch height was greater (p<0.01) with a frequency of 1 Hz at all time periods studied both in preparations that are blocked with pancuronium and in those that are blocked with rocuronium. CONCLUSION: The frequency of stimulation interferes significantly with the installation of neuromuscular blockade produced by pancuronium and rocuronium, since the reduction in amplitude of the rat diaphragm response was greater for 1 Hz frequencies, at all periods studied.

The effect of walking with high-heeled shoes on the leg venous pressure.

It is common belief that the use of high-heeled shoes is deleterious to venous return, by impairing the efficiency of the muscular calf pump. Ambulatory venous pressure obtained with dorsal foot venipuncture is the gold standard in the evaluation of venous pressure during walking, but it is not routinely used in clinical practice. The objective of the present study was to determine the variations in leg venous pressure obtained with a new noninvasive method, in individuals without venous disease, walking without shoes and wearing high-heeled shoes. A new method of evaluation of the venous pressure by means of air plethysmography was applied to 10 volunteers (20 limbs). The patients were evaluated while standing, with orthostatic flexion and extension foot movements, and while walking on a treadmill barefooted and wearing high-heeled shoes. It was found that the variation on the cuff pressure during walking with high-heeled shoes was higher than the variation on the cuff pressure walking barefooted (52.2 +/- 8.89 X 26.65 +/- 6.7 mm Hg, p < 0.0001), and the final hydrostatic venous pressure was lower (51.5 +/- 12.78 X 61.5 +/- 8.44 mm Hg). The use of high-heeled shoes increases muscular effort during walking and diminishes the leg venous pressure compared with barefooted.

Proporção entre os segmentos do anel da valva tricúspide normal: um parâmetro para realização da anuloplastia valvar / Proportion among the segments of the normal tricuspid valve annulus: parameter for valve annuloplasty

OBJETIVO: Determinar a proporção existente entre os segmentos do anel da valva tricúspide normal em humanos. MÉTODO: Foram estudados 30 corações de cadáveres humanos não formolizados, com menos de 6h de período post-mortem, sem lesões congênitas ou adquiridas e com valvas tricúspides continentes. A continência valvar foi confirmada por injeção de água sob pressão no interior do ventrículo direito estando a valva pulmonar fechada. Fotos digitais da valva tricúspide com o anel valvar íntegro, e após secção e retificação, foram avaliadas por programa de computador. Compararam-se as medidas médias e as razões entre elas nas condições de anel íntegro e retificado. RESULTADOS: Com o anel valvar íntegro, os valores médios do perímetro, segmento septal e ântero-posterior foram 105mm (±12,7), 30,6mm (±3,7) e 74mm (±9,4), respectivamente. Com o anel valvar retificado, os valores médios foram 117,5mm (±13,3), 32mm (±3,7), 46,3mm (±8,3) e 39,1mm (±8,5), respectivamente para perímetro, segmento septal, anterior e posterior. As razões médias entre o segmento ântero-posterior e o septal foram 2,43 (±0,212) e 2,67 (±0,304), respectivamente, em anéis íntegros e retificados. Houve diferenças significantes nas medidas do perímetro (p<0,0001), do segmento septal (p=0,003) e do segmento ântero-posterior (p<0,0001) entre anéis íntegros e retificados. As razões entre segmento ântero-posterior e septal também apresentaram diferença significante (p=0,0005). CONCLUSÃO: A proporção entre o segmento septal e o segmento ântero-posterior, do anel da valva tricúspide normal em humanos, é igual a 1: 2,43. A secção e retificação do anel tricuspídeo altera as medidas de seus segmentos e suas relações.

OBJECTIVE: The purpose of this study was to determine the proportions among the segments of the human tricuspid valve annulus. METHODS: A descriptive autopsy study was made of 30 human hearts without fixation, within six hours of death, without congenital or acquired lesions and without tricuspid regurgitation. Tricuspid valve insufficiency was excluded by the infusion of pressurized water in the right ventricle with the pulmonary valve closed. Digital images of the tricuspid ring in its anatomical position and after flattening were analyzed by specific software. The mean measurements and ratios were compared in the two different situations. RESULTS: The mean measurements of the perimeter, septal and antero-posterior segments of the tricuspid ring in the anatomical position were: 105mm (±12.7), 30.6mm (±3.7) and 74mm (±9.4), respectively. When flattened, the mean measurement of the perimeter was 117.5mm (±13.3) and sizes of the septal, anterior and posterior segments were 32mm (±3.7), 46.3mm (±8.3) and 39.1mm (±8.5), respectively. The mean ratio between the antero-posterior and septal segments was 2.43 (±0.212) in the anatomical position and when flattened it was 2.67 (±0.304). Statistical differences were observed in the measurements of perimeter (p<0.0001), septal segment (p=0.003) and antero-posterior segment (p<0.0001) in both situations. Statistical differences also occurred in the ratios between the antero-posterior and septal segments (p=0.0005). CONCLUSION: The proportion between the septal and antero-posterior segments of the normal human tricuspid valve is 1:2.43. Flattening the tricuspid ring to measure the segments, changes the values and the ratios between them.