Complicación respiratoria en el postoperatorio tardío en un paciente con distrofia miotónica tipo I. Reporte de un caso / Respiratory complication in the late postoperative period in a patient with type I myotonic dystrophy. Case report

Myotonic dystrophy is an uncommon disease, characterised by disorders of the muscle membrane. Its clinical manifestations are muscle weakness, difficulty at initiating movements and delayed muscle relaxation. Carriers of this disease are very sensitive to anaesthetic drugs. Residual neuromuscular blockade is common among these patients, leaving them at risk of various postoperative complications. Proper neuromuscular blockade reversal is therefore crucial. We report the case of an 18-year-old male with myotonic dystrophy type I (Steinert's disease), who was admitted for a complicated hydatid cyst. He required a laparotomy, which was done under general anesthesia with no intraoperative incidents. He was extubated at the end of the procedure, with 94% response at the train-of-four (TOF) and adequate spontaneous ventilation. No reversal for neuromuscular blockade was given. The patient evolved favourably during the postoperative phase. However, in the later postoperatory period the patient presented severe respiratory complications. Proper anaesthetic management of these patients, as described in the literature, includes the use of non-depolarising muscle relaxants, monitoring of muscle relaxation and reversal of neuromuscular blockade. The combination of rocuronium and sugammadex appears to convey the optimum reversal required for these cases.

Las distrofias miotónicas son enfermedades poco comunes, caracterizadas por trastornos a nivel de la membrana muscular. Clínicamente se manifiestan por debilidad muscular progresiva, dificultad al iniciar movimientos y retardo en la relajación muscular. Los portadores de este grupo de enfermedades tienen una marcada sensibilidad a los fármacos anestésicos. Es habitual que presenten bloqueo neuromuscular residual, arriesgándose a sufrir diversas complicaciones postoperatorias. Por ello, es importante realizar una reversión adecuada de la relajación muscular en estos pacientes. Presentamos el caso de un paciente masculino de 18 años, con distrofia miotónica de Steinert tipo I, que ingresa para laparotomía por quiste hidatídico hepático complicado. Recibió anestesia general sin incidentes. Es extubado con una respuesta al tren-de-cuatro (TOF) de 94% y ventilación espontánea adecuada. No se realiza reversión del bloqueo neuromuscular y evoluciona favorablemente en el postoperatorio inmediato. Sin embargo, en el período postoperatorio tardío, presenta complicaciones respiratorias severas. El adecuado manejo de estos pacientes, según lo recomendado en la literatura, requiere el uso de relajantes no-depolarizantes, monitorización y reversión del bloqueo neuromuscular, siendo probablemente la combinación de rocuronio y sugammadex, la más adecuada para estos fines.

Inadvertent injection of succinylcholine as an epidural test dose / Injeção inadvertida de succinilcolina como uma dose teste epidural

Abstract Background and objectives: Epidural action of neuromuscular blocking agents could be explained under the light of their physicochemical characteristics and epidural space properties. In the literature there are few cases of accidental neuromuscular agent's epidural administration, manifesting mainly with neuromuscular blockade institution or fasciculations. Case report: We report a case of accidental succinylcholine administration as an epidural test dose, in a female patient undergoing scheduled laparotomy, under combined general and epidural anesthesia. Approximately 2 min after the succinylcholine injection the patient complained for shortness of breath, while mild fasciculations appeared in her trunk and face, managed by immediate general anesthesia institution. With the exception of a relatively longer duration of neuromuscular blockade compared with intravenous administration, no neurological or cardiovascular sequelae or other symptoms of local or systemic toxicity were observed. Conclusions: Oral administration of diazepam seems to lessen the adverse effects from accidental epidural administration of succinylcholine. The meticulous and discriminative labeling of syringes, as well as keeping persistent cautions during all anesthesia procedures remains of crucial importance.

Resumo Justificativa e objetivos: A ação epidural de agentes bloqueadores neuromusculares pode ser explicada à luz de suas características físico-químicas e propriedades do espaço epidural. Na literatura existem poucos casos sobre a administração acidental em espaço epidural de agente neuromuscular que se manifesta principalmente com a instituição de bloqueio neuromuscular ou fasciculações. Relato de caso: Relatamos um caso de administração acidental de succinilcolina como uma dose teste epidural em uma paciente submetida à laparotomia programada, sob anestesia combinada geral e peridural. Aproximadamente dois minutos após a injeção de succinilcolina, a paciente queixou-se de falta de ar, enquanto fasciculações leves apareceram em seu tronco e rosto, tratadas com a instituição imediata de anestesia geral. Exceto pela duração relativamente longa do bloqueio neuromuscular em comparação com a administração intravenosa, sequelas neurológicas ou cardiovasculares ou outros sintomas de toxicidade local ou sistêmica não foram observados. Conclusões: A administração oral de diazepam parece diminuir os efeitos adversos da administração epidural acidental de succinilcolina. A meticulosidade e discriminação dos rótulos das seringas, bem como os cuidados persistentes mantidos durante todos os procedimentos de anestesia, continuam a ser de importância crucial.

Anaphylactic reaction from atracurium

For induction of anaesthesia many agents are administered intravenously, anaphylactic reaction can occur to any of these agents

Neuromuscular blocking agents are most commonly implicated as the cause of anaphylactic reaction in anaesthesia practice

Amino-steroids, benzylisoquinoliniums and suxamethonium are being commonly used for intubation and perioperative muscle relaxation. We are presenting a case of anaphylactic reaction to benzylisoquinolinium i.e. atracurium in a young patient. The patient was revived with a prompt diagnosis and treatment

Successful early application of extracorporeal membrane oxygenation to support cardiopulmonary resuscitation for a patient suffering from severe malignant hyperthermia and cardiac arrest: a case report / 대한마취과학회지

Malignant hyperthermia (MH) may lead to metabolic crisis of skeletal muscle in susceptible individuals following exposure to triggering agents such as volatile anesthetics or depolarizing muscle relaxants. MH is a rare and a potentially lethal disease, which can lead to cardiac arrest. We report a case of severe MH, in which the rapidly evolving signs of hypermetabolism eventually resulted in cardiac arrest. Despite conventional treatments following cardiopulmonary resuscitation, the patient's vital signs did not improve. Therefore, we applied extracorporeal membrane oxygenation for providing hemodynamic support.

Relaxant effects of a hydroalcoholic extract of Ruta graveolens on isolated rat tracheal rings

BACKGROUND: Ruta graveolens L. (R. graveolens) is a medicinal plant employed in non-traditional medicines that has various therapeutic properties, including anthelmintic, and vasodilatory actions, among others. We evaluated the trachea-relaxant effects of hydroalcoholic extract of R. graveolens against potassium chloride (KCl)- and carbachol-induced contraction of rat tracheal rings in an isolated organ bath. RESULTS: The results showed that the airway smooth muscle contraction induced by the depolarizing agent (KCl) and cholinergic agonist (carbachol) was markedly reduced by R. graveolens in a concentration-dependent manner, with maximum values of 109 ± 7.9 % and 118 ± 2.6 %, respectively (changes in tension expressed as positive percentages of change in proportion to maximum contraction), at the concentration of 45 µg/mL (half-maximal inhibitory concentration IC50: 35.5 µg/mL and 27.8 µg/mL for KCl- and carbachol-induced contraction, respectively). Additionally, the presence of R. graveolens produced rightward parallel displacement of carbachol dose-response curves and reduced over 35 % of the maximum smooth muscle contraction. CONCLUSIONS: The hydroalcoholic extract of R. graveolens exhibited relaxant activity on rat tracheal rings. The results suggest that the trachea-relaxant effect is mediated by a non-competitive antagonistic mechanism. More detailed studies are needed to identify the target of the inhibition, and to determine more precisely the pharmacological mechanisms involved in the observed biological effects.

Evaluación del Rocuronio en la práctica clínica / Evaluation of Rocuronium in clinical practice

El Rocuronio, relajante muscular no despolarizante de tipo esteroideo aparece en el mercado en la década del 90, siendo su principal característica el presentar un rápido inicio de acción, una duración de acción intermedia y una baja potencia. Presenta alta sensibilidad en los músculos relevantes para la intubación (aductores laríngeos, diafragma y masetero). Por lo que se ha propuesto como una alternativa a la succinilcolina, pudiendo utilizarse en la inducción en secuencia rápida (1) Una de las ventajas de esta droga, es que a dosis altas (1,2 mg/Kg) logra buenas condiciones para la intubación orotraqueal, según estudios de aprobacion de la FDA, en 42 seg con un rango de 24 a 102 seg.. A dosis habituales (0.6 mg/Kg) se logran excelentes condiciones de intubación en la mayoría de los ptes en menos de 120 seg (2). Las dosis altas aumenta el tiempo de relajación, un tiempo medio de 67 min, con un rango de 38-160 min (3)(7). La Agencia Española de Medicamento (EMA) considera que a dosis de 0,6 mg/k se obtienen condiciones para la IOT en 60 seg en la mayoría de los ptes, en el 80% de los ptes las condiciones de IOT se consideraron excelentes (4). La duración clínica (recuperación espontánea del 25% de la transmisión neuromuscular) es de 30 a 40 minutos con esta dosis; la duración total (tiempo de recuperación espontánea del 90% de la transmisión neuromuscular) es de 50 minutos. A dosis plena 1mg/Kg de Rocuronio se obtuvieron condiciones de IOT dentro de los 60 segundos entre el 93-96% de los pacientes, de estos el 70% se consideran excelentes; la duración clínica se aproxima a 1 hora (5). Si bien, a nivel nacional, Andujar y col (6) compararon la utilización de rocuronio en secuencia inversa con la utilización de succinilcolina, y concluyen que las condiciones de intubación son buenas en ambas grupos lográndose un rápido acceso de la vía aérea, en nuestro medio, no existe hasta el momento ningún trabajo que describa el comportamiento clínico del Rocuronio. El objetivo general del presente trabajo es describir el comportamiento clínico del Rocuronio, determinar el tiempo real de inicio de acción, la duración de acción de las dosis más utilizadas y determinar el tiempo mínimo para lograr las mejores condiciones de intubación en nuestra población. Como objetivos secundario, cerciorarnos que la presentación farmacológica utilizada en el Hospital de Clínicas cumple con las características propias de la droga.

Evaluation of rocuronium in clinical practice. Rocuronium, nondepolarizing muscle relaxant steroidal type appear on the market in the 90s, its main feature presenting a rapid onset of action, an intermediate duration of action and low power. It is highly sensitive for the relevant muscles for intubation (laryngeal adductors, diaphragm and masseter). As has been proposed as an alternative to succinylcholine and can be used in rapid sequence induction (1) One advantage of this drug is that at high doses (1.2 mg / kg) achieved good conditions for intubation, according to approval studies by FDA, in 42 seconds with a range of 24-102 sec. At regular doses (0.6 mg / Kg) excellent intubation conditions are achieved in most patients in less than 120 seconds (2). High doses increases the relaxation time, an average time of 67 min, with a range of 38-160 min (3) (7). The Spanish Medicines Agency (EMA) believes that a dose of 0.6 mg / k are obtained conditions for the IOT in 60 sec in most patients, 80% of IOT patients conditions were considered excellent (4). The clinical duration (25% spontaneous recovery of neuromuscular transmission) is 30 to 40 minutes at this dose; the total duration (time of spontaneous recovery of 90% of neuromuscular transmission) is 50 minutes. A full dose 1mg / kg rocuronium IOT conditions were obtained within 60 seconds between 93-96% of patients, of these 70% are considered excellent; clinical duration is close to 1 hour (5). While nationally, Andujar et al (6) compared the use of rocuronium in reverse order with the use of succinylcholine, and conclude that intubation conditions are good in both groups achieving a quick airway, in our medium, there is so far no work describing the clinical behavior of rocuronium.

Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry.

Some current challenges in research on air pollution and health / Desafíos actuales de la investigación sobre contaminación del aire y salud

This commentary addresses some of the diverse questions of current interest with regard to the health effects of air pollution, including exposure-response relationships, toxicity of inhaled particles and risks to health, multipollutant mixtures, traffic-related pollution, accountability research, and issues with susceptibility and vulnerability. It considers the challenges posed to researchers as they attempt to provide useful evidence for policy-makers relevant to these issues. This commentary accompanies papers giving the results from the ESCALA project, a multi-city study in Latin America that has an overall goal of providing policy-relevant results. While progress has been made in improving air quality, driven by epidemiological evidence that air pollution is adversely affecting public health, the research questions have become more subtle and challenging as levels of air pollution dropped. More research is still needed, but also novel methods and approaches to address these new questions.

Este comentario aborda algunos de los temas de interés actual en relación con los efectos de la contaminación del aire sobre la salud, tales como las relaciones exposición-respuesta, la toxicidad y riesgos para la salud de las partículas inhaladas, las mezclas de contaminantes múltiples, la contaminación relacionada con el tráfico, la investigación sobre responsabilidad, y los problemas de susceptibilidad y vulnerabilidad. Considera los retos que se presentan a los investigadores que intentan proporcionar evidencia para los responsables políticos en estas cuestiones. Este texto acompaña otros trabajos con resultados del proyecto ESCALA, un estudio en varias ciudades de América Latina que tiene como objetivo general proporcionar resultados relevantes para la política pública. Aunque ha habido avances para mejorar la calidad del aire, gracias a la evidencia epidemiológica de que la contaminación aérea está afectando negativamente a la salud pública, las preguntas de investigación se han vuelto más sutiles y difíciles a medida que los niveles de contaminación se reducen. Se necesita más investigación, pero también nuevos métodos y enfoques capaces de enfrentar estas preguntas.

Epidural anesthesia for a lumbar discectomy in a patient with paramyotonia congenita: A case report

Paramyotonia congenita is a rare hereditary skeletal muscle disease characterized by exercise- or cold-induced myotonia. Anesthesiologists should make any efforts to prevent perioperative myotonic attack and muscle weakness in patients with this kind of disorder. Specifically, the administration of depolarizing muscle relaxants should be avoided and serum potassium level as well as body temperature should be carefully managed. The present report describes our experiences with successful epidural anesthesia in a patient with paramyotonia congenita who underwent a lumbar discectomy.

Sugammadex: clinical development and practical use / 대한마취과학회지

Sugammadex is belonging to a new class of drugs: the selective relaxant binding agents. Sugammadex can reverse residual paralysis by encapsulating free circulating non depolarizing muscle relaxants. The mains advantages of sugammadex when compared with conventional anticholinesterase agents are a much faster recovery time and the unique ability, for the first time, to reverse rapidly and efficiently deep levels of neuromuscular blockade. However it only works for reversal of rocuronium or vecuronium-induced neuromuscular blockade. When administered 3 min after rocuronium the use of a large dose (16 mg/kg) can even reverse rocuronium significantly faster than the spontaneous recovery after succinylcholine.

Progress on suxamethonium chloride analysis / 法医学杂志

Abstract: Suxamethonium chloride is a depolarizing muscle relaxant used in general anesthesia. In overdose, it causes adverse reactions such as bradycardia, arrhythmia, cardiac arrest, and death. The article reviews the progress on testing methods of suxamethonium chloride such as infrared spectroscopy, chemical color reaction, chemical titration, enzyme electrode, chromatography and mass spectrometry.

A suspicious case of malignant hyperthermia during general anesthesia with desflurane: A case report

Malignant hyperthermia (MH) is an inherited disorder of skeletal muscle manifested as a life threatening hypermetabolic crisis in susceptible individuals following exposure to commonly used inhaled anesthetics and depolarizing muscle relaxants. We experienced a suspicious case of MH in 34-year-old male during transfemoral cerebral angiography embolization under general anesthesia with desflurane. The episode emerged 15 minutes after induction of general anesthesia using propofol, rocuronium, remifentanil, desflurane. Desflurane is a recently developed inhaled anesthetics and there has been no case report of MH related with it in Korea. When we suspected episode, vigorous treatment was carried out, symptoms were resolved without dantrolene administration.

Succinilcolina vs rocuronio, escogencia clínica mediante un análisis de decisión médica / Succinylcholine vs rocuronium, clnical choice through a medical decision analysis

Objetivo: Realizar un análisis de decisión para escogencia entre succionilcolina y rocuronio en la inducción de secuencia rápida con base en su eficacia y la presentación de eventos adversos. Métodos: Se realizó el análisis de decisión mediante la construcción de árboles de decisiones, con sus respectivos nodos de decisión, oportunidades y utilidades. Los datos fueron tomados de la literatura médica y de una encuesta a profesionales de la anestesia y estudiantes de posgrado en anestesiología; luego éstos fueron procesados por el software Treenage con la realización de los análisis de sensibilidad. Resultados: El árbol de decisión de la literatura médica demuestra un valor esperado para la rama de succionilcolina de 6.50, superior al de la rama de rocuronio, cuyo valor es de 5.22. El árbol de decisión de la encuesta muestra a la succionilcolina como opción a escoger con un valor esperado de 9.08, por encima del valor esperado del rocuronio el cual es de 8.17. Conclusión: La succionilcolina es la mejor escogencia con base en su efectividad clínica para condiciones de intubación traqueal en la inducción de secuencia rápida, y también, es la mejor opción cuando se tienen en cuenta sus efectos adversos.

Objective: To perform a decision analysis for choosing between succinylcholine and rocuronium in a rapid sequence induction situation based on their efficacy and reported adverse effects. Methods: Decision analysis by building decision trees, with their respective decision nodes, opportunities and usefulness was made. The data was taken from the medical literature and a survey performed on anesthesia professionals and anesthesiology residents; then was processed by the Treenage software with sensitivity analysis. Results: The decision tree based on the medical literature shows an expected value for the succinylcholine branch of 6.50, higher than the rocuronium branch with a value of 5.22. The decision tree of the survey shows the succinylcholine as an option to choose with an expected value of 9.08, above the expected value of rocuronium which is 8.17. Conclusion: Succinylcholine is the best choice based on tis clinical effectiveness conditions for tracheal intubation in rapid sequence induction, and it is the best option when consideration its adverse effects.

Malignant hyperthermia during cesarean section: A case report

Malignant hyperthermia is manifestated in susceptible individuals exposed to triggering drugs, such as depolarizing muscle relaxants and inhalational anesthetics. Various musculoskeletal abnormalities, such as scoliosis, hernias and strabismus, have been associated with malignant hyperthermia susceptibility. During cesarean section of the patient who had undergone scoliosis correction surgery, we experienced malingnant hyperthermia due to succinylcholine and inhalation anesthetics. In our case, as soon as we suspected the episode, all anesthetics were stopped and anesthetic machines were changed to unexposed anesthetic machine for inhalational anesthetics. Dantrolene was given intravenously and the patient was cooled by tepid sponging, cooled fluids. The patient recovered normal temperature and consciousness without any complications.

Relajantes musculares en la clínica anestesiológica / Muscle relaxants in clinical anesthesiology

Esta obra científica es apropiada tanto para el anestesiólogo práctico, independientemente de los años que tenga de profesión y como texto para los médicos residentes en formación. En ambos casos, además del conocimiento actualizado al año de edición, estoy seguro contribuirá a la apertura mental necesaria para un mejor ejercicio científico de nuestra noble tarea. Dedica su espacio a la monitorización del bloqueo neuromuscular, en particular a la acelerometría que es el método más práctico de todos los usados. La autora la emplea de rutina, con registros gráfico y numérico de las variables observadas y en el libro es un pilar fundamental que ayuda al lector a comprender y asimilar la moyoría de los temas tratados

Uso dos principais bloqueadores neuromusculares em anestesia / Use of the key blockers in anesthesia

A introdução dos agentes bloqueadores neuromusculares em 1942 marcou , sem dúvida, uma nova era na história da anestesia. Foi possível acessar cavidades sem interferência de contrações musculares voluntárias e da mesma forma manter por longos períodos um suporte ventilatório adequado. O objetivo deste trabalho é propor uma revisão bibliográfica sobre os principais bloqueadores neuromusculares , enfatizando um pouco da farmacocinética e farmacodinâmica de cada agente bem como suas principais aplicações e restrições. Por fim, fazemos uma breve revisão dos agentes anticolinesterásicos que são usados na reversão dos bloqueios neuromusculares farmacológicos.

Anesthetic experience for patients with malignant hyperthermia susceptibility determined by molecular genetic test: A report of 2 cases / 대한마취과학회지

Malignant hyperthermia (MH) is a potentially fatal pharmacogenetic disorder manifested as a life threatening hypermetabolic crisis in susceptible individuals following exposure to inhalation anesthetics and to depolarizing muscle relaxants. The preoperative diagnosis of MH susceptibility is difficult. The gold standard for determination of MH susceptibility is the in vitro contracture test. However, it is invasive, requiring skeletal muscle biopsy and is not widely available. Recent advances in genetic testing for mutations that result in MH during anesthesia have helped some genetic test have limitations in clinical application due to the diversity of mutations. In Korea, we found the RYR1 genetic mutation by molecular genetic testing for MH susceptibility in a family for which MH had occurred. Based on the results of genetic testing, we could known MH susceptibility of 2 patients. We believe that the genetic testing for MH can be developed and used with some limitations in clinical settings in Korea.

Precurarización con rocuronio y d-tubocurarina: otra perspectiva / Precurarization with rocuronium and d-tubocurarine

Objetivo: Estudiar la precurarización de la succinilcolina utilizando d-tubocurarina y rocuronio introduciendo los métodos restrictivo, conceptos de velocidad de acción y recuperación y una nueva semiología para evaluar las fasciculaciones. Material y método: Se administraron succinilcolina (1 mg x Kg-1) (n =21) sola o precedida por rocuronio o d-tubocurarina (60 ó 50 ug x Kg-1) (n =21 c/u), determinándose: la fase inicial de comienzo hasta 80 por ciento de bloqueo, tiempo de comienzo, máximo efecto, duración clínica, tiempo de reversión espontánea entre 10 por ciento y 25 por ciento y 25 por ciento a 50 por ciento. Se calculó la velocidad de acción (inicial, final y global) como la relación tiempo/bloqueo fraccionado y la velocidad de recuperación. El método restrictivo fue empleado para el estudio del tiempo de comienzo, utilizando un rango restringido de bloqueo. Las fasciculaciones fueron evaluadas por su intensidad en seis regiones anatómicas por cuatro observadores imparciales e independientes y las medias de sus valoraciones utilizadas para analizarlas. Resultados: Aparentemente ambos desfasciculantes prolongan la fase inicial, tiempo de comienzo y velocidad de la succinilcolina, pero el método restrictivo únicamente lo confirmó para el tiempo de comienzo y la velocidad global. La velocidad inicial fue más rápida que la final. El rocuronio redujo el efecto y la duración clínica e incrementó la velocidad de recuperación de la succinilcolina. Las fasciculaciones fueron más frecuentes e intensas en el tronco y miembro superior izquierdo, pero los precurarizantes las redujeron tanto en intensidad como localización Discusión: La precurarización no modifica la fase inicial de comienzo, surgiendo la posibilidad de practicar una intubación temprana. Debido al acortamiento que provoca la precurarización con rocuronio se hace evidente la necesidad precoz de nuevas dosis de relajantes.

Objective: To study the precurarization of succinylcholine with d-tubocurarine and rocuronium, using the restrictive method, speed of action and recovery principles and a particular evaluation for fasciculations Material & Methods: Patients received succinylcholine (1 mg x Kg-1) (n =21) either alone or preceded by d-tubocurarine or rocuronium (60 ó 50 micron g x Kg-1) (n =21 e/a), and the following clinical measurements were made: earlyphase of onset time (up to 80 percent blockade), onset time, maximal block, clinical duration and recovery time between 10 percent and 25 percent and 25 percent to 50 percent. Speed of action (initial, final and global)as the ratio between time and fractional blockade and speed of recovery, were calculated. Restrictive method was used for the study of the entire onset time on patients included in a limited range of final block. Intensity of fasciculations was evaluated by four independent observers blind to the drugs used in six anatomical regions and their mean values used for analysis. Results: Apparently, precurarizing drugs prolonged initial phase, onset time and reduced speed for succinylcholine, but only onset time and global speed were confirmed by restrictive method. After rocuronium, maximal effect as well as clinical duration of succinylcholine werereduced and speed of recovery increased. Fasciculations were more frequent and intense at the trunk and left upper arm, but precurarization reduced both intensity and localization prevalence. Discussion: As lack of changes on the initial phase of onset time for succinylcholine inducedby precurarization was noticed, an early tracheal intubation could be contemplated. Due to reduction on clinical duration after rocuronium,new doses of muscle relaxants are sooner necessary. The present method for evaluation of fasciculations shows how far they are spread and how effective precurarization was, given rise to doubts on previous results.