Two forgotten induction agents; etomidate versus thiopental sodium with rocuronium for rapid sequence induction

To assess the effect on intubating conditions and haemodynamic response on intubation of two different induction agents etomidate and thiopental sodium with rocuronium during rapid sequence induction. This prospective quasi experimentalstudy was conducted in Department Of Anaesthesia, SICU and Pain Management, Dow Medical College, Civil Hospital Karachi and Abbasi Shaheed Hospital Karachi Medical and Dental College over a period of one year. Total 120 American Society of Anaesthesiologists [ASA] physical class I and II, adult patients of either gender, aged between 18 to 60 years, undergoing elective surgery were allocated randomly into two equal groups to receive either intravenous thiopental sodium [Group NTR] or etomidate[Group NER] for rapid sequence induction. Group NER was given nalbuphine 0.1 mg/kg, induction agent etomidate 3 mg/kg with muscle relaxant rocuronium 1.0 mg/kg while in group NTR induction agent thiopental sodium was given in the dose of 4 mg/kg with nalbuphine and rocuronium in the same doses. After sixty seconds, laryngoscopy was done. Intubating condition was assessed using the criteria of Cooper and colleagues: ease of intubation, condition of vocal cords and response to intubation. Cardiovascular response on intubation in terms of systolic and diastolic blood pressure and heart rate was evaluated at 0,1, 3 and 5 minutes. Demographic data were comparable between the groups. Intubating conditions which were assessed in terms of ease of laryngoscopy, condition of vocal cords at intubation and intubation response coughing, bucking and diaphragmatic movement were significantly better in the group NER [p<0.05]. Similarly, arterial blood pressure remained close to base line in NER group but there was significant fall in both systolic and diastolic blood pressure in group NTR. However, there was no significant difference in change in the heart rate in the groups. Etomidate-rocuronium is better than thiopental-rocuronium in terms of intubating conditions and haemodynamic stability during rapid sequence induction in non-septic surgical patients in emergency department

Incidencia de parálisis muscular residual con el uso de relajantes musculares no despolarizantes de duración intermedia / Incidence of residual muscular paralysis produced by nondepolarizing neuromuscular blockers

Objetivo: El objetivo de este estudio fue analizar la incidencia de parálisis muscular residual producida por bloqueadores neuromusculares no despolarizantes en la Unidad de Cuidados Postanestésicos (UCPA)del Hospital Miguel Pérez Carreño, Caracas, Venezuela. Material y Métodos: Se incluyeron 246 pacientes en los que se midió la relación T4/T1 al momento del ingreso a la unidad, a los tres y a los cinco minutos. El criterio para considerar un paciente sin bloqueo residual fue una relación T4/T1 > 0,9. Además se monitorizó la saturación de oxígeno, variables demográficas, características de la cirugía y la anestesia, y uso o no de reversión. Resultados: El promedio de edad fue de 36,45 años, con un peso de 62,85 kg. La incidencia de parálisis residual en la UCPA fue 51,2 por ciento para el momento de llegada a la unidad, de 47,6 por ciento a los tres minutosy de 46,7 por ciento al quinto minuto, siendo los pacientes de mayor edad los más afectadas (p= 0,002). Cuando se comparó la utilización de reversión con la presencia de relajación residual no se encontró diferencia estadísticamente significativa (p = 0,516). Conclusión: La incidencia de parálisis muscular residual en la UCPA es alta en nuestro centro (51 por ciento), similar a lo que reporta la literatura a nivel mundial; los pacientes más afectados fueron los de mayor edad y el uso de reversión no excluyó la presencia de esta entidad.

Objective: The outcome of this study was to analyze the incidence of residual muscular paralysis produced by nondepolarizing neuromuscular blockers in the PostAnesthetic Care Unit (PACU) of the Doctor Miguel Pérez Carreño Hospital, Caracas, Venezuela. Methods: 246 patients were included. T4/T1 ratio was measured at the moment of arriving to the postoperative unit, 3 and 5 minutes later. Criteria for consideringno residual effects was a T4/T1 > 0,9. Moreover, oxygen saturation was monitored. Demographic variables,characteristics of surgery and anesthesia and the usage or not of reversion drugs were noted. Results: The average of age was 36,45 years, with an average weight of 62,85 kg. The incidence of residual muscularparalysis in the PACU was 51,2 percent at the time of arriving, and 47,6 percent and 46,7 percent at the 3rd and 5th minutes respectively, being the more aged patients the most affected (p = 0,002). When compared the usage ofreversion with the presence of residual muscular paralysis no difference statistically significant was found(p = 0,516). Conclusion: The incidence of residual muscular paralysis in PACU at our center was high (51 percent) and similar to the one reported in worldwide literature; the most affected were the more aged patients and the use of reversion did not exclude the presence of this entity.

Comparative study of succinylcholine and precurarization with rocuronium on muscular effects in patients undergoing surgery under general anaesthesia

Succinylcholine remains the drug of choice in conditions where rapid paralysis and airway control are priorities. However it is associated with muscular side effects that have an overall incidence ranging from five to 83 percent. The administration of small doses of nondepolarizing muscle relaxants before the administration of succinylcholine has been shown to decrease the incidence and severity of muscular side effects experienced by the patients. This study was aimed at evaluating the efficacy of technique in reducing the muscular side effects of succinylcholine. Sixty healthy adults were enrolled in the study who were scheduled for minor muscle cutting surgeries under genera lanaesthesia. They were assigned at random to two groups of thirty patients each. They randomly received succinylcholine for intubation and a precurarization dose of rocuronium followed by succinylcholine for intubation. Intraoperative fasciculations and postoperative myalgia were graded and scored. There was a significantly increased incidence of fasciculations and myalgia in the succinlcholine group. In the precurarization group the incidence and severity of fasciculations and myalgia was significantly less as compared to the group which received succinylcholine alone. We found significant correlation between fasciculations and myalgia in the succinylchloine group. Present study concluded that precurarization with rocuronium was effective in reducing the succinylcholine-induced fasciculations and myalgia

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

The influence of lidocaine and racemic bupivacaine on neuromuscular blockade produced by rocuronium: a study in rat phrenic nerve-diaphragm preparation / Influência da lidocaína e da bupivacaína racêmica no bloqueio neuromuscular produzido pelo rocurônio: estudo em preparação nervo frênico-diafragma de rato

PURPOSE: To evaluate in vitro lidocaine and racemic bupivacaine effects in neuromuscular transmission and in neuromuscular blockade produced by rocuronium. METHODS: Rats were distributed in 5 groups (n = 5) in agreement with the studied drugs: lidocaine, racemic bupivacaine, rocuronium, separately (Groups I, II, III); rocuronium in preparations exposed to local anesthetics (Groups IV, V). The concentrations used were: 20 µg/mL, 5 µg/mL and 4 µg/mL, for lidocaine, bupivacaine and rocuronium, respectively. It was evaluated: 1) amplitude of diaphragm muscle response to indirect stimulation, before and 60 minutes after separately addition of lidocaine, racemic bupivacaine and rocuronium and the association of local anesthetics - rocuronium; 2) membrane potentials (MP) and miniature end-plate potentials (MEPP). RESULTS: Lidocaine and bupivacaine separately didn't alter the amplitude of muscle response and MP. In preparations previously exposed to lidocaine and racemic bupivacaine, the rocuronium blockade was significantly larger (90.10 ± 9.15 percent and 100 percent, respectively), in relation to the produced by rocuronium separately (73.12 ± 9.89 percent). Lidocaine caused an increase in the frequency of MEPP, being followed by blockade; racemic bupivacaine produced decrease being followed by blockade. CONCLUSIONS: Local anesthetics potentiated the blockade caused by rocuronium. The alterations of MEPP identify presynaptic action.

OBJETIVO: Avaliar in vitro os efeitos da lidocaína e bupivacaína racêmica na transmissão neuromuscular e no bloqueio neuromuscular produzido pelo rocurônio. MÉTODOS: Ratos foram distribuídos em 5 grupos (n = 5) de acordo com a droga estudada: lidocaina, bupivacaína racêmica, rocurônio, isoladamente (Grupos I, II, III); rocurõnio em preparações expostas aos anestésicos locais (Grupos IV, V). As concentrações utilizadas foram: 20 µg/mL, 5 µg/mL e 4 µg/mL, para lidocaína, bupivacaína e rocurônio, respectivamente. Avaliou-se: 1) amplitude das respostas do músculo diafragma à estimulação indireta, antes e 60 minutos após a adição da lidocaína, bupivacaína racêmica e rocurônio isoladamente e da associação anestésicos locais - rocurônio; 2) potenciais de membrana (PM) e potenciais de placa terminal em miniatura (PPTM). RESULTADOS: A lidocaína e a bupivacaína isoladamente não alteraram a amplitude das respostas musculares e os PM. Nas preparações previamente expostas a lidocaína e a bupivacaína racêmica, o bloqueio com o rocurônio foi significativamente maior (90,10 ± 9,15 por cento e 100 por cento, respectivamente), em relação ao produzido pelo rocurônio isoladamente (73,12 ± 9,89 por cento). A lidocaína causou aumento na freqüência dos PPTM, seguido de bloqueio; a bupivacaína racêmica produziu diminuição seguida de bloqueio. CONCLUSÕES: Os anestésicos locais potencializaram o bloqueio causado pelo rocurônio. As alterações do PPTM identificam ação pré-sináptica.

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.

In vitro and in vivo neuromuscular effects of atracurium and rocuronium in rats treated with carbamazepine for seven days / Efeitos neuromusculares in vitro e in vivo do atracúrio e do rocurônio em ratos submetidos a tratamento de sete dias com carbamazepina / Efectos neuromusculares in vitro e in vivo del atracurio y del rocuronio en ratones sometidos a tratamiento de siete días con carbamazepina

JUSTIFICATIVA E OBJETIVOS: Trata-se de um estudo experimental que investigou in vitro e in vivo o bloqueio neuromuscular produzido pelo rocurônio e atracúrio em ratos tratados com carbamazepina e determinou as concentrações de citocromo P450 e b5 redutase em microssomos hepáticos. MÉTODO: Ratos foram tratados por sete dias com carbamazepina (CBZ) - 40 mg.kg-1 pelo método de gavagem e sacrificados no oitavo dia sob anestesia com uretana. As preparações in vitro e in vivo foram montadas de acordo com as técnicas de Bulbring e de Leeuwin e Wolters, respectivamente. As concentrações e doses utilizadas dos bloqueadores nas preparações in vitro e in vivo foram, respectivamente, 20 µg.mL-1 e 0,5 mg.kg-1 para atracúrio (ATC); 4 µg.mL-1 e 0,6 mg.kg-1 para rocurônio (ROC). Cada protocolo teve um n = 5 e as respostas foram observadas por 60 minutos. Os efeitos do ATC e ROC foram avaliados nas preparações de ratos tratados (Cbz t) e comparados com os observados nas de ratos não-tratados (CBZst). As concentrações de citocromo P450 e b5 redutase foram determinadas em microssomos isolados de fígados de ratos tratados (CBZt) e comparadas com as obtidas em ratos não tratados (CBZst). RESULTADOS: A carbamazepina não alterou a amplitude das respostas musculares; in vitro e in vivo, não houve diferença entre o bloqueio neuromuscular produzido pelo atracúrio nas preparações CBZt versus CBZst; o bloqueio neuromuscular produzido pelo rocurônio nas preparações CBZt foi potencializado in vitro. A carbamazepina não alterou as concentrações de citocromo P450 e b5. CONCLUSÕES: O tratamento por sete dias com carbamazepina não influenciou no bloqueio produzido pelo atracúrio, e alterou in vitro os efeitos do rocurônio. O tempo de tratamento não foi suficiente para causar indução enzimática e diminuir a sensibilidade ao rocurônio.

BACKGROUND AND OBJECTIVES: This experimental study investigated the in vitro and in vivo neuromuscular blockade of rocuronium and atracurium in rats treated with carbamazepine and determined the concentration of cytochrome P450 and b5 reductase in hepatic microsomes. METHODS: Rats were treated with carbamazepine (CBZ) - 40 mg.kg-1 by gavage and sacrificed on the eighth day under anesthesia with urethane. In vitro and in vivo preparations followed the techniques of Bulbring and Leeuwin and Wolters, respectively. Concentrations and doses of the neuromuscular blockers used in in vitro and in vivo preparations were, respectively, 20 µg.mL-1 and 0.5 mg.kg-1 for atracurium (ATC); and 4 µg.kg-1 and 0.6 mg.kg-1 for rocuronium (ROC). Each protocol had an n = 5 and the response was observed for 60 minutes. The effects of ATC and ROC were evaluated in the preparations of rats treated with carbamazepine (CBZt) and compared to those of non-treated rats (CBZst). The concentration of cytochrome P450 and b5 reductase were determined in hepatic chromosomes of rats treated with carbamazepine (CBZt) and non-treated rats (CBZst). RESULTS: Carbamazepine did not change the amplitude of neuromuscular response; differences in the neuromuscular blockade produced by atracurium in CBZ1 preparations were not observed, in vitro or in vivo, when compared with CBZst; the neuromuscular blockade produced by rocuronium in CBZt preparations was potentiated in vitro. Carbamazepine did not change the concentrations of cytochrome P450 and b5. CONCLUSIONS: Seven-day treatment with carbamazepine did not change the neuromuscular blockade produce by atracurium, but altered the in vitro effects of rocuronium. The duration of the treatment was not enough to cause enzymatic induction and decrease the sensitivity to rocuronium.

JUSTIFICATIVA Y OBJETIVOS: Se trata de un estudio experimental que investigó in vitro e in vivo el bloqueo neuromuscular producido por el rocuronio y atracurio en ratones tratados con carbamazepina y determinó las concentraciones de citocromo P450 y b5 reductasis en microsomas hepáticos. MÉTODO: Ratones fueron tratados por siete días con carbamazepina (CBZ) - 40 mg.kg-1 a través de una sonda y sacrificados al octavo día bajo anestesia con uretana. Las preparaciones in vitro e in vivo fueron montadas de acuerdo con las técnicas de Bulbring y de Leeuwin y Wolters, respectivamente. Las concentraciones y dosis utilizadas de los bloqueadores en las preparaciones in vitro e in vivo fueron, respectivamente, 20 µg.mL-1 y 0,5 mg.kg-1 para atracurio (ATC); 4 µg.mL-1 y 0,6 mg.kg-1 para rocuronio (ROC). Cada protocolo tuvo un n = 5 y las respuestas fueron observadas por 60 minutos. Los efectos del ATC y ROC fueron evaluados en las preparaciones de ratones tratados (Cbz t) y comparados a los observados en los de ratones no tratados (CBZst). Las concentraciones de citocromo P450 y b5 reductasis fueron determinadas en microsomas aislados de hígados de ratones tratados (CBZt) y comparadas con las obtenidas en ratones no tratados (CBZst) RESULTADOS: La carbamazepina no alteró la amplitud de las respuestas musculares; in vitro y in vivo, no hubo diferencia entre el bloqueo neuromuscular producido por el atracurio en las preparaciones CBZt versus CBZst; el bloqueo neuromuscular producido por el Rocuronio en las preparaciones CBZt fue potenciado in vitro. La carbamazepina no alteró las concentraciones de citocromo P450 y b5. CONCLUSIONES: El tratamiento por siete días con carbamazepina, no influenció en el bloqueo producido por el atracurio, y alteró in vitro los efectos del rocuronio. El tiempo de tratamiento no fue suficiente para causar la inducción enzimática y disminuir la sensibilidad al rocuronio.

Correlación entre la concentración molar del rocuronio y su tiempo de comienzo o velocidad de acción / Correlation between molar concentration of rocuroniom and its time of onset or speed of action

Objetivo: Estudiar la correlación entre dosis subparalizantes de rocuronio con el tiempo de comienzo y utilizarla para su predicción. Material y método: Cinco grupos de pacientes recibieron 0.34, 0.68, 1, 1.38 o 2.8 x DE50 de rocuronio, y se determinó el máximo efecto, el tiempo para alcanzarlo (TC), las concentraciones molares (µM/kg) y la velocidad de acción (VA), relación entre tiempo y efecto o viceversa de cada dosis. Para la correlación, los valores se convirtieron en logaritmos (log) o raíz cuadrada (V2). De la línea de regresión se obtuvieron la fórmula, R al cuadrado y la significación estadística. Resultados: La correlación entre log µM/kg con Tc y VA (seg/por ciento o por ciento/seg) se tradujo en los siguientes resultados: R2= 0.972,0.845 y 0.845, y una p= 0.001, 0.027 y 0.027, respectivamente. Al resolver las fórmulas de regresión se puedo predecir el TC y VA. Cuando los valores se transforman en V al cuadrado los resultados fueron similares. Discusión: El TC de un bloqueante neuromuscular está ligado a su efecto, y la permeabilidad al tamaño de sus moléculas o µM/kg, la cual a su vez es función de la dosis. El estudio no comprueba la similitud propuesta del TC entre las bajas dosis de los relajantes musculares. Los resultados demuestran que existe una alta y significativa correlación entre la µM/kg de las dosis subparalíticas de rocuronio con las tres formas de estudiar el período de comienzo. También pone en evidencia que a través de la misma correlación es posible hacer predicciones sobre los parámetros de comienzo.

The effect of ephedrine on the onset time of rocuronium in Thai patients.

The aim of this study was to determine the effect of ephedrine on the onset time of rocuronium. The study population was 60 ASA physical status 1 and 2 patients, aged 15-60 years scheduled for elective surgery under general anesthesia at Ramathibodi Hospital. The patients were randomly assigned into 2 groups. Group I (ephedrine group), ephedrine 70 microg/kg was given 1 minute before induction and group II (control group), saline was given instead of ephedrine and midazolam 7.5 mg was given orally 30-60 minutes before the induction. Anesthesia was induced with fentanyl 1 microg/kg and sodium thiopentone 3-5 mg/kg. The patient was intubated with 0.9 mg/kg of rocuronium. The intubation time (from rocuronium administration to the time of intubation) was predetermined by the Dixon's up and down method (with 5 seconds as a step size) for each patient and started at 60 seconds for the first patient in each group. The intubation time in the ephedrine group (39.41 +/- 4.64 seconds) was significantly different from the control group (59.17 +/- 9.00 seconds); p-value < 0.01. The hemodynamics were similar in both groups. Conclusion: Intravenous ephedrine shortened the onset time of rocuronium with no significant adverse hemodynamic effects. As an alternative to suxamethonium for rapid intubation, the authors recommend the use of ephedrine 70 microg/kg at one minute before induction followed by 0.9 mg/kg of rocuronium intravenously in healthy patients. The intubation could be achieved at 40 seconds after the administration.

Effects of isoflurane on the actions of neuromuscular blockers on the muscle nicotine acetylcholine receptors / 华中科技大学学报（医学）（英德文版）

In this study, we tested the hypothesis that volatile anesthetic enhancement of muscle relaxation is the result of combined drug effects on the nicotinic acetylcholine receptors. The poly A m RNA from muscle by isolation were microinjected into Xenopus oocytes for receptor expression. Concentration-effect curves for the inhibition of Ach-induced currents were established for vecuronium, rocuranium, and isoflurane. Subsequently, inhibitory effects of NDMRs were studied in the presence of the isoflurane at a concentration equivalent to half the concentration producing a 50% inhibition alone. All tested drugs produced rapid and readily reversible concentration-dependent inhibition. The 50% inhibitory concentration values were 889 micromol/L (95% CI: 711-1214 micromol). 33.4 micromol (95% CI: 27.1-41.7 nmol) and 9.2 nmol (95% CI: 7.9-12.3 nmol) for isoflurane. rocuranium and vecuronium, respectively. Coapplication of isoflurane significantly enhanced the inhibitory effects of rocuranium and vecuronium, and it was especially so at low concentration of NMDRs. Isoflurane increases the potency of NDMRs, possibly by enhancing antagonist affinity at the receptor site.

Comparison of pharmacokinetics and pharmacodynamics of rocuronium infusion in adults and children

This study compared the pharmacokinetics and pharmacokinetic-dynamic relationship of rocuronium in children and adults, we studied 10 children [4-8 years] and 10 adults [20-40 years] ASA I and II underwent surgical operation in Kasr-El-Aini hospital. After induction with thiopentone [2-6 mg/kg], fentanyl 5-10 Hg/kg, infusion of rocuronium 0.09 mg/kg/min. in children group and 0.1 mg/kg/min. in the adults group. The infusion was given over +/- 5 minutes. The patients were monitored with the EMG of the adductor pollicis muscle. When neuromuscular block reached 85% endotracheal intubation, and then mechanical ventilation was started Maintenance of anesthesia with isoflurane 0.5- 1%, O[2]/NO[2] 50% in both groups. Arterial sample were obtained over 240 min./ Plasma concentrations were measured by HpLc. pharmacokinetic-dynamic variables were calculated using sheiner model, and the Hill equation. Statistical analysis was performed using the Mann-Whitney U test [p < 0.05]. The mean administered dose of rocuronium infusion was 0.65 +/- 0.09 mg/kg/hour in adults group and 0.35 +/- 0.1 mg/kg/hour in children group. Children differed from adults in plasma clearance 5.2 +/- 0.043 versus 7.65 +/- 1.05 ml/min./kg in adults group, distribution volume at steady state 220 +/- 20 ml/kg in children group and 168+50 ml/kg in adults group, mean residence time 50.5 +/- 9.0 [min.] in children group and 26 +/- 9.0 [min.] in adults group, concentration in effect compartment at 50% block 1.19 +/- 0.4 mg/liter in children group and 1.3 +/- 0.3 mg/liter in adults group, calculated mean ED[90] values were 0.345 +/- 0.077 in adults group, 0.25 +/- 0.067 in children group. The time course of neuromuscular block did not differ. The study concluded that infusion of rocuronium has different pharmacokinetic-dynamic in both adults and children, but it can be safely used in children especially when the infused dose adjusted by using the EMG

Influência do propofol e do etomidato no bloqueio neuromuscular produzido pelo rocurônio: avaliação pela aceleromiografia / Influence of propofol and etomidate on rocuronium-induced neuromuscular block: evaluation with acceleromyography

Justificativa e objetivos - Alguns hipnóticos podem interagir com os bloqueadores neuromusculares (BNM) potencializando seus efeitos. O objetivo deste estudo foi avaliar a influência do propofol e do etomidato sobre o bloqueio neuromuscular produzido pelo rocurônio. Método - Foram incluídos no estudo 60 pacientes, estado físico ASA I e II, submetidos a cirurgias eletivas sob anestesia geral, distribuídos aleatoriamente em dois grupos de acordo com o hipnótico empregado; Grupo I (propofol) e Grupo II (etomidato). Todos os pacientes receberam midazolam (0,1 mg.kgðû) por via muscular como medicação pré-anestésica, 30 minutos antes da cirurgia. A indução anestésica foi obtida com propofol (2,5 mg.kgðû) ou etomidato (0,3 mg.kgðû) precedido de alfentanil (50 µg.kgðû) e seguido de rocurônio (0,6 mg.kgðû). Os pacientes foram ventilados sob máscara com oxigênio a 100 por cento até a obtenção de redução de 75 por cento ou mais na amplitude da resposta do músculo adutor do polegar, quando foram realizadas as manobras de laringoscopia e intubação traqueal. A função neuromuscular foi monitorizada com aceleromiografia. Foram avaliados: tempo de início de ação do rocurônio (T1 < = 25 por cento); tempo para instalação do bloqueio neuromuscular total; grau de bloqueio neuromuscular no momento da intubação traqueal; condições de intubação traqueal e repercussões hemodinâmicas. Resultados - Os tempos de início de ação e instalação de bloqueio neuromuscular total (segundos) produzido pelo rocurônio foram: Grupo I (48,20 ñ 10,85 s e 58,87 ñ 10,73 s) e Grupo II (51,20 ñ 13,80 s e 64,27 ñ 18,55 s). O grau de bloqueio neuromuscular no momento da intubação traqueal foi: Grupo I (77,50 por cento) e Grupo II (76,96 por cento). As condições de intubação traqueal foram satisfatórias em 100 por cento dos pacientes do Grupo I e em 83,33 por cento no Grupo II. Nos dois grupos, após a injeção do hipnótico, observouðse diminuição significativa da pressão arterial média seguida de elevação. Conclusões - O propofol e o etomidato comportaramðse de maneira semelhante em relação à instalação do bloqueio neuromuscular e às condições de intubação traqueal produzidos pelo rocurônio

Rocuronium administration in children during isoflurane anesthesia: neuromuscular effects

Brockground. The time-course of the effect of rocuronium during isoflurane anesthesia in children rarely evaluated. Forty-five children, aged 2-14 years, ASA 1, undergoing elective surgery and receiving isoflurane anesthesia, were studied. Methods. Patients randomly received a dose of 400, 600, or 800 µg/kg of rocuronium. The first response to control height (T1:TO) was fitted to time in order to obtain times to onset of action (TOA) including time to 90 (b10) and 99.9 percent (B100) of relaxation and to spontaneous reconver of 10 (T10), 25 (t25), 50 (t75), and 90 percent (T90) of neuromuscular function (NMF). Each time was compared among group. Linear regression analysis between the TOA or the times to spontaneous recovery of NMF (TSRNMF) and age or weight were also performed. Results. The TOA were similar among the three groups while TSRNF in children receiving 600 or 800 µg/kg were longer (p< 0.05) than children receiving 400 µg/kg. The T10 and T25 were related to age (p= 0.05), whereas T10, T50, T75, and T90 were related to weight (p< 0.01). These relationships were stringer in males than females. Conclusions. Maximal relaxation was reached in all children receiving 600 or 800 µg/kg of rocuronium. The TSRNMF were mainly related to the weight of the children, and gender affected each relationship. Widely variable response were observed with all three doses

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