Duración del bloqueo neuromuscular con succinilcolina y su relación con niveles de colinesterasa plasmática en pacientes sépticos: Hospital Central Universitario Dr. Antonio María Pineda / Neuromuscular blockade duration with succinylcholine and its correlation with levels of plasma cholinesterase in septic patients: Hospital Central Universitario Dr. Antonio María Pineda

La succinilcolina es un fármaco neuromuscular despolarizante generalmente utilizado en el contexto de protocolo de intubación de secuencia rápida indicada en pacientes en los cuales es necesario asegurar la vía aérea en menos de sesenta segundos. Se realizó un estudio descriptivo transversal con el objetivo de determinar la duración del bloqueo neuromuscular con succinilcolina y los niveles de colinesterasa plasmática en pacientes sépticos intervenidos en el Hospital Central Universitario Dr. Antonio María Pineda. Se incluyeron 30 pacientes con sepsis con un promedio de edad de 49,6 ± 17,4 años y predominio del sexo masculino (70%); la principal indicación de cirugía abdominal fue obstrucción intestinal (36,6%) y peritonitis secundaria (23,3%). Los valores de colinesterasa plasmática se registraron disminuidos en 42,8% de los hombres y 33,3% de las mujeres encontrándose valores promedios de 5554,1 ± 1220,5 U/L y 4770,1 ± 1627,4 U/L, respectivamente. La duración del bloqueo neuromuscular fue mayor de 14 minutos en 66,6% de las mujeres; el promedio de duración fue de 14,4 ± 5,1 min (mujeres) y 9,4 ± 4,3 min en hombres. Hubo una pobre correlación entre los niveles de colinesterasa plasmática y la duración así como el tiempo de recuperación del bloqueo neuromuscular. En conclusión, el bloqueo neuromuscular prolongado debido a la baja actividad de la colinesterasa después de la administración de succinilcolina se presenta en menos de la mitad de los pacientes sépticos estudiados(AU)

Succinylcholine is a depolarizing neuromuscular drug generally used in the context of rapid sequence intubation indicated in patients in whom it is necessary to secure the airway in less than sixty seconds. A descriptive cross-sectional study was conducted in order to determine the duration of neuromuscular blockade with succinylcholine and plasma cholinesterase levels in septic patients admitted at Hospital Central Universitario Dr. Antonio Maria Pineda. A sample of 30 patients with sepsis were studied, with a mean age of 49.6 ± 17.4 years, predominantly male (70%). The main indication for abdominal surgery was intestinal obstruction (36.6%) and secondary peritonitis (23.3%). Diminished values of plasma cholinesterase were recorded in 42.8% of men and 33.3% of women; mean plasma levels were 5554.1 ± 1220.5 U/L and 4770.1 ± 1627.4 U/L, respectively. Duration of neuromuscular blockade was longer in women (66.6%) with an average duration of 14.4 ± 5.1 min and 9.4 ± 4.3 min for men. A poor correlation between cholinesterase plasmatic levels and duration as well as time of recovery of neuromuscular blockage was found. Prolonged neuromuscular blockade is due to low cholinesterase activity after administration of succinylcholine and occurs in less than half of septic patients studied(AU)

Comparative study of intubating conditions after Rocuronium and Suxamethonium [study of 50 cases]

To compare the Intubating Conditions and Changes in heart rate [HR] achieved after suxamethonium chloride and rocuronium bromide, during intubation, in patients between ages 11-50 years out of which 4 were in paediatric age group [11-12 years] and 46 in adult group [19-50 years]. This study was conducted at the Armed Forces Hospital Sharourah kingdom of Saudi Arabia during six months period starting from 01/02/09. Fifty patients aged between 11-50 years, 4 including in paediatric age group [11-12 years] and 46 in adult age group [19-50 years], requiring general anesthesia for various surgical procedures, were randomly divided into two groups, i.e. Group A in which Rocuronium bromide, 0.9 mg kg-1 was given for intubation [[n=25] [23 adults, 2 children]] Group B in which Suxamethonium chloride 1.5 mg kg -1 was used for intubation [[n=25] [23 adults, 2 children]] Intubating conditions were observed at 60 seconds after intravenous bolus administration of suxamethonium or Rocuronium. HR was also observed immediately before induction [Pre-Op], at 60 seconds after bolus of Suxamethonium or Rocuronium [Immediately after relaxation], Immediately after intubation and then five minutes after intubation. Intubating conditions were rated as excellent in 96% [n=24 Twenty two adults two children] and good in 4% [n=1 Adult] of the patients who received Rocuronium and excellent in 100% of the patients who received Suxamethonium. There were no statistically significant changes observed in HR at all observation times between the two groups. It is concluded from this study that intubation can be performed under good to excellent conditions at 60 seconds after a bolus dose of Rocuronium of 0.9 mg kg-1. As far as affect on HR are concerned, our study indicate no significant difference between the two drugs. The result of this study indicates that to facilitate intubation using rapid sequence induction technique Rocuronium is a reasonably good alternative to Suxamethonium

Effect of rocuronium compared with succinylcholine on intraocular pressure and intubating conditions during rapid sequence induction of anesthesia

Rapid sequence intubation is developed to secure the airway rapidly and safely. Succinylcholine provides excellent intubating conditions and thus remains the muscle relaxant of choice in emergency situation. The aim of this study was to compare the effects of rocuronium and succuinylcholine on intraocular pressure [IOP] during rapid sequence induction of anesthesia using propofol and fintanyl. In addition assessment of intubating conditions after administration of both succinylcholine and rocuronium. In a randomized, double-blind study we studied 40 adult patients, randomly allocated to one of two groups. Anesthesia was induced with fentanyl 2 microg/kg and propofol 2 mg/kg. This was followed by succinylcholine 1.5 mg/kg [group S; n=20] or rocuronium 0.6 mg/kg [group R; n=20]. Laryngoscopy and tracheal intubation were performed 60 seconds later. IOP, mean arterial blood pressure [MAP] and heart rate [HR] were measured before induction, immediately before intubation and every minute after intubation for 5 minutes. Tonopen tonometer was used to measure IOP and the mean of three consequative readings obtained in the right eye at each measurement time was recorded. Simple scoring system was used to evaluate intubating conditions. In the succinylcholine group, IOP was significantly greater than that in rocuronium group mean 23.7 +/- [SEM 1.6] vs mean 14.2 +/- [SEM 0.9] mm Hg; p<0.001. Intubating conditions were similar in both groups. Rocuronium 0.6 mg/kg when used with propofol and fentanyl during rapid sequence induction of anesthesia does not cause a rise in IOP. Thus, it may be a suitable alternative to succinylcholine, especially in cases of penetrating eye injury

La precurización: nuevas evidencias / Precurization: new evidence

Introducción: La succinilcolina continúa siendo utilizada y su efecto colateral más frecuente, las fasciculaciones, siguen evaluándose de manera visual, parcializada y subjetivamente. También persiste el empleo preventivo de relajantes no despolarizantes. Nuestro objetivo es estudiar la consiguiente interacción después de evaluar ampliamente esa complicación. Material y métodos: En cuatro grupos (n = 15 c/u) se utilizaron aleatoriamente succinilcolina 1 mg/kg sola o precedida por 50, 10 y 8 mcg/kg de d'tubocurarina, mivacurio o pancuronio, respectivamente. Se determinaron el tiempo para un bloqueo del 80 por ciento, el máximo efecto y la duración clínica. Las fasciculaciones fueron evaluadas por cuatro observadores independientes que desconocían los agentes y la técnica, dos a cada lado, en seis regiones anatómicas: los dos miembros superiores, los dos inferiores, el tronco y la cabeza. La intensidad en cada región fue calificada del O a 3. Resultados: Los fármacos prolongan el inicio de la acción de la succinilcolina en forma consistente y significativa (p < 0.05; 33 vs 57, 48 Y 48 segundos); la d'tubocurarina alarga el comienzo de dicha acción (95 vs 69 segundos) y el pancuronio la duración (9 vs 7,6 y 6 minutos). El máximo efecto no se modifica. La precurarización redujo la cuenta total de fasciculaciones: la d'tubocurarina fue más activa y el mivacurio menos (10 vs 0.333,7.384 y 3.533). Discusión y conclusiones: El inicio de acción después de la precurarización no excede el minuto y no sería un obstáculo para una intubación precoz. La duración clínica puede guiar la administración sucesiva de relajantes. Para evaluar las fasciculaciones hemos utilizado una metodología cuantitativa y cualitativa con observadores imparciales, incluyendo esos parámetros en una sola cifra susceptible de analizar estadísticamente.

Rocuronio / Rocuronium

Se trata de un relajante muscular no despolarizante de tiempo más corto de todos los disponibles en clínica en la actualidad. El maximo bloqueo despúes de la administración endovenosa de una dosis de intubación ocurre en promedio a los 90 segundos, separándolosólo 30 segundos de la succinilcolina. La evaluación final de si el rocuronio reemplazára a la succinilcolina en situaciones de urgencia, y específicamente en el estómago lleno, está por verse. La valoración debe hacerse teniendo presente que no siempre concuerdan la clínica con pequeñas varaciones estadísticass. Es necesario hacer un balance costo beneficio de las ventajas de aislar la tráquea 30 segundos antes con la succinilcolina y sus riesgos, o 30 segundos despúes con una droga carente de toda complicación. El rocuronio es un relante muscular de amplio margen de seguridad que puede ser usado en el caso diario, con la excepción de los pacientes con antecedentes de hipersensibilidad y en pacientes con patología hepática severa. No está contraindicado en pacientes con patología renal, aunque se recomienda adecuar la dosis y monitorizar la relajación. Dependiendo de su costo, el rocuronio está destinado a reemplazar a otros bloqueadores neuromusculares de duración intermedia

Relajantes musculares en pediatría / Muscle relaxants in pediatrics

Desde el nacimiento, en el organismo ocurren cambios anatómicos y fisiológicos. Es en la primera etapa de la vida donde estas variaciones son más marcadas y ocurren más rápidamente. Así, la respuesta a los fármacos administrados en pediatría depende principalmente de estos cambios. Los relajantes musculares no escapan a esta regla, por tal motivo, para su uso correcto es necesario conocer las variables farmacocinéticas y farmacodinámicas en el recién nacido, lactante y niño

study of atypical cholinesterase in offspring's of a heterozygous couple

Deficiency of plasma cholinesterase [ChE] was detected in several members of the family tested on suspicion of genetic modification of enzyme structure. Prolonged apnea following administration of suxamethomum [succinylecholine] was due to low levels of cholinesterase from homozygote for atypical gene [E[1a], E[1a]]. Screening of immediate relations showed atypical genetic response in cholinesterase [ChE] activity in offsprings of a heterozygous couple. [ChE [E[1a], E[1u]]. As our data are in accordance with results obtained by other investigators, this observation cannot be regarded as exceptional

On mechanism of action of ethanol-induced contraction of frog rectus abdominis.

Ethanol in low doses (0.5 to 4 M) causes contraction of isolated frog rectus abdominis muscle. Higher concentration did not produce any further increase in maximum response. Pretreatment with dantrolene produced partial but equal inhibition of acetylcholine (Ach) induced as well as ethanol-induced contraction in equieffective doses. Pretreatment with pancuronium produced right and downward shift of ethanol induced contraction. Pretreatment with succinylcholine produced persistent contraction of tissue and this response remained unaffected on subsequent treatment with Ach as well as ethanol. Pretreatment with hemicholinium abolished ethanol induced contraction, although tissue remained viable as confirmed on addition of Ach. The contraction induced by ethanol decreased on pretreatment with dantrolene as well as in Ca2+ free ringer. The results indicate that ethanol induced contraction may be due to release of Ach or Ach like neurotransmitter at neuromuscular junction and calcium acts as mediator to produce these effects.

Neuromuscular and hemodynamic effects of mivacurium and succinylcholine in adult patients during nitrous oxide-propofol-fentanyl anesthesia

The neuromuscular and hem+odynamic effects of mivacurium 0.15 mg/kg and succinylcholine 1 mg/kg were compared in 26 adult patients (ASA I and II) during nitrous oxide-oxygen-propofol-fentanyl anesthesia. Neuromuscular block was monitored by recording the compound electromyogram of the hypothenar muscle resulting from supramaximal train-of-four stimuli applied to the ulnar nerve. Time to onset of over 95% block and duration to 25% recovery of control twitch after injection of mivacurium were significantly longer than for succinylcholine (201 +/- 37.6 vs 54 +/- 5.2 sec and 13.0 +/- 2.2 vs 8.4 +/- 2.1 min; mean +/- SD). Onset of mivacurium with priming technique was shortened (125 +/- 20.7 sec), but was also slower than that of succinylcholine. Although the recovery index during spontaneous recovery was significantly longer for mivacurium than for succinylcholine (6.9 +/- 1.3 vs 5.1 +/- 0.9 min), antagonism with neostigmine at 25% recovery of twitch height sufficiently facilitated the recovery index of mivacurium (4.5 +/- 1.0 min) to a level similar to that of succinylcholine with no statistical difference. The hemodynamic effects of mivacurium were few as compared to those of succinylcholine. In conclusion, mivacurium is considered to have additional advantages for short procedures when succinylcholine is undesirable.

Modification of atracurium or vecuronium blockade and their reversal by succinylcholine in the cat

The interaction between succinylcholine (SCC) and non-depolarizers, atracurium or vecuronium was investigated in 36 cats of either sex using the sciatic nerve-anterior tibialis muscle preparation. Additionally, the relation of SCC to pseudocholinesterase activity was examined. The duration of action of vecuronium (6.5 +/- 1.3 to 7.3 +/- 2.2 minutes) in cats pretreated with SCC was greater than those (2.0 +/- 0.6 minutes) in non-pretreated cats. However, SCC had no influence on the duration of atracurium. The serum pseudocholinesterase activity was decreased after the injection of atracurium or neostigmine in contrast to vecuronium. The authors conclude that the prior administration of SCC prolongs the duration of vecuronium but not that of atracurium, and pseudocholinesterase activity is not related to the prolonging effect of SCC.

Efeitos cardiovasculares dos relaxantes neuromusculares / Cardiovascular effects of neuromuscular relaxants

O autor faz uma revisäo das açöes farmacológicas dos relaxantes neuromusculares sobre o sistema cardiovascular. Os mecanismos básicos pelos quais os relaxantes neuromusculares induzem efeitos cardiovasculares säo sumarizados. Entre estes incluem a liberaçäo de histamina, bloqueio ganglionar, bloqueio dos receptores muscarínicos no sistema cardiovascular e a recaptaçäo das catecolaminas a nível neural. Consideraçöes sobre os mais recentes agentes, atracúrio e vecurônio, säo feitas, especialmente quanto aos seus efeitos hemodinâmicos

Açao da succinilcolina sobre os músculos extra-oculares em pacientes com heterotropias / Action of succinylcholine over the extra-ocular muscles in patients with heterotropies

O autor examinou 27 pacientes com distúrbio da motilidade ocular, submetidos à anestesia geral para cirurgia de estrabismo. Esses pacientes foram divididos em dois grupos: o Grupo 1, constituído por 20 pacientes, denominado Grupo-Teste, e o Grupo 2, constituído por sete pacientes, denominado Grupo-Controle. Nos pacientes do Grupo-Teste, a succinilcolina I.V. foi usada após uma medida de referência, fazendo-se a segunda medida dois minutos depois. Aguardou-se esse período para que as fasciculações musculares que se seguem ao uso da droga não falseassem os resultados, aproveitando-o para fazer intubação orotraqueal. Em seguida, foram feitas tantas medidas quantas necessárias, respeitando-se sempre um intervalo de três minutos até o retorno das medidas aos valores iniciais. Nos pacientes do Grupo-Controle, nos quais não se usou a succinilcolina, as medidas foram em número de quatro e em intervalos regulares de três minutos. O estudo mostrou que a succinilcolina I.V. aumenta a força de contração dos músculos extra-oculares num tempo médio de 9,80 minutos (até 17 minutos em um caso) e permite que se meça quantitativamente essa variação. Portanto, os testes de dução forçada e de equilíbrio de forças elásticas do olho não devem ser realizadas antes de 20 minutos em pacientes que receberam succinilcolina.