Nefopam does not influence onset and recovery profiles of rocuronium-induced neuromuscular block: a prospective, double-blinded, randomized, controlled study

BACKGROUND: We investigated the hypothesis that pretreatment with nefopam 20 mg would influence the onset and recovery profiles of rocuronium-induced neuromuscular block. METHODS: After Institutional Review Board approval, 134 patients, aged between 20–65 years, belonging to the American Society of Anesthesiologists physical status classification I or II, were randomly allocated to receive either 0.9% normal saline (control group) or nefopam 20 mg (nefopam group), infused over one hour before induction of anesthesia. Anesthesia was induced with remifentanil and propofol, followed by endotracheal intubation with rocuronium 0.6 mg/kg. We recorded the lag time, onset time, clinical duration, recovery index, recovery time, and total recovery time. RESULTS: We included 111 patients in the final analysis. The lag time, onset time, clinical duration, recovery index, recovery time, and total recovery time of the nefopam group (n = 57) were not significantly different compared with that of the control group (n = 54). CONCLUSIONS: Pretreatment with nefopam 20 mg one hour before induction of anesthesia does not have a significant influence on the onset and recovery profiles of rocuronium-induced neuromuscular block.

Effects of adenosine receptor agonist on the rocuronium-induced neuromuscular block and sugammadex-induced recovery / 대한마취과학회지

BACKGROUND: Several types of receptors are found at neuromuscular presynaptic membranes. Presynaptic inhibitory A1 and facilitatory A2A receptors mediate different modulatory functions on acetylcholine release. This study investigated whether adenosine A1 receptor agonist contributes to the first twitch tension (T1) of train-of-four (TOF) stimulation depression and TOF fade during rocuronium-induced neuromuscular blockade, and sugammadex-induced recovery. METHODS: Phrenic nerve-diaphragm tissues were obtained from 30 adult Sprague-Dawley rats. Each tissue specimen was randomly allocated to either control group or 2-chloroadenosine (CADO, 10 μM) group. One hour of reaction time was allowed before initiating main experimental data collection. Loading and boost doses of rocuronium were sequentially administered until > 95% depression of the T1 was achieved. After confirming that there was no T1 twitch tension response, 15 min of resting time was allowed, after which sugammadex was administered. Recovery profiles (T1, TOF ratio [TOFR], and recovery index) were collected for 1 h and compared between groups. RESULTS: There were statistically significant differences on amount of rocuronium (actually used during experiment), TOFR changes during concentration-response of rocuronium (P = 0.04), and recovery profiles (P < 0.01) of CADO group comparing with the control group. However, at the initial phase of this experiment, dose-response of rocuronium in each group demonstrated no statistically significant differences (P = 0.12). CONCLUSIONS: The adenosine A1 receptor agonist (CADO) influenced the TOFR and the recovery profile. After activating adenosine receptor, sugammadex-induced recovery from rocuronium-induced neuromuscular block was delayed.

Effect of levetiracetam on rocuronium duration in patients undergoing cerebrovascular surgery

BACKGROUND: It has long been held that antiepileptics reduce the duration of action, and increase the requirement for, neuromuscular blocking agents. However, levetiracetam, a relatively novel antiepileptic agent, possesses different pharmacokinetic properties to other, conventional antiepileptics, such that its effect on neuromuscular blocking agents might also differ. The purpose of this retrospective study is to investigate the effect of levetiracetam on the clinical duration of rocuronium. METHODS: In this study, the duration of neuromuscular blockade induced by rocuronium was compared between control and levetiracetam-receiving groups. The data were retrieved from one of our previous studies. RESULTS: The control and levetiracetam groups comprised 16 and 13 patients, respectively, all of whom underwent cerebrovascular surgery. Subjects received supplementary rocuronium (0.15 mg/kg) whenever the train-of-four count reached 2 during surgery. The interval between supplementary rocuronium (0.15 mg/kg) injections was significantly longer in the levetiracetam vs. control group (50 and 39 minutes, respectively; P = 0.036). CONCLUSIONS: The present results challenge the convention that antiepileptics decrease the duration of action of neuromuscular blockers, thereby alerting clinicians to the possibility of prolonged neuromuscular blockade in patients taking levetiracetam. Anesthetic management should encompass careful neuromuscular monitoring in such patients.

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 sepsis on vecuronium-induced inhibition of acetylcholine release in neuromuscular junction in rats / 中华麻醉学杂志

Objective To investigate the effect of sepsis on vecuronium-induced inhibition of acetylcholine release in neuromuscular junction in rats.Methods Thirty-six adult male SPF SpragueDawley rats,aged 2-3 months,weighing 200-220 g,were randomly divided into 3 groups (n=12 each) using a random number table:control group (group C),sham operation group (group S) and sepsis group (group Sep).Sepsis was induced by cecum ligation and puncture (CLP) in rats anesthetized with intraperitoneal chloral hydrate 350 mg/kg.At 12 h after CLP,the sciatic nerve-pretibial muscle was prepared.Vecuronium was added to the culture medium with the final concentration of 0.08 μg/ml,and the sciatic nerve-pretibial muscle was incubated for 15 min.Before and after administration,evoked endplate potentials (EPPs) and miniature endplate potentiais (MEPPs) were recorded by using intracellular microelectrode.EPP/MEPP ratio was calculated.Results Compared to C and S groups,EPPs,MEPPs and EPP/MEPP ratio were significantly increased before and after administration in group Sep.EPPs,MEPPs and EPP/MEPP ratio were significantly lower after administration than before administration in the three groups.Conclusion Sepsis can promote acetylcholine release in neuromuscular junction,thus weakening vecuronium-induced inhibition of acetylcholine release in neuromuscular junction in rats.

Effects of different methods of administration on clinical pharmacodynamics of cisatracurium during liver transplantation / 中华麻醉学杂志

Objective To evaluate the effects of different methods of administration on clinical pharmacodynamics of cisatracurium during liver transplantation.Methods Twenty-four ASA physical status Ⅲ patients of both sexes,aged 18-63 yr,weighing 60-88 kg,with body mass index of 20-30 kg/m2,scheduled for elective liver transplantation,were randomly divided into 2 groups (n =12 each):continuous infusion group (group C) and intermittent bolus injection group (group Ⅰ).The total intravenous anesthesia was used during surgery.When T1 recovered to 10％ of control height after induction of anesthesia,continuous infusion of cisatracurium was started with an initial rate of 1.5 μg· kg-1 · min-1,and the infusion rate was manually adjusted to maintain T1 at about 10％ in group C,and intermittent iv boluses of cisatracurium 0.03 mg/kg were given to maintain T1 ≤ 10％ in group Ⅰ.The use of muscle relaxants was stopped immediately after peritoneum closure.The consumption of cisatracurium per minute,time for T1 to recover from 10％ to 25％,recovery index and time for recovery of spontaneous breathing after surgery were recorded.Results Compared with group Ⅰ,the consumption of cisatracurium per minute was significantly reduced and the time for recovery of spontaneous breathing after surgery was shortened (P ＜ 0.05),and no significant changes were found in the time for T1 to recover from 10％ to 25％ and recovery index in group C (P ＞ 0.05).Conclusion Compared with intermittent bolus injection,continuous infusion of cisatracurium during liver transplantation is helpful in improving the clinical potency of the muscle relaxant and in reducing the occurrence of complications during anesthesia recovery period.

Caso de anafilaxia induzida por rocurônio tratado com o auxílio de sugamadex / Case of anaphylaxis induced by rocuronium treated with sugammadex / Caso de anafilaxia inducida por rocuronio tratado con la ayuda del sugamadex

JUSTIFICATIVA E OBJETIVOS: A anafilaxia durante a anestesia é um evento raro que pode ocorrer em até 1:20.000 casos sendo que aproximadamente 60% a 70% destes casos são secundários ao uso de ralaxantes musculares onde os mais implicados a succinilcolina e o rocurônio. O objetivo deste relato foi descrever o tratamento de um caso de anafilaxia induzida por rocurônio com resposta inadequada a terapia tradicional e resolução do caso após o uso do sugamadex. RELATO DO CASO: Paciente do sexo feminino, com 62 anos de idade, 72 kg, foi encaminhada ao centro cirúrgico para tratamento de hematoma extradural após acidente em domicílio. Foi monitorada com oxímetro de pulso, cardioscópio e tensiômetro para medida da pressão anterial não invasiva (PA). Seus dados basais foram: PA de 138/80 mm Hg, frequência cardíaca (FC) de 80 bpm e saturação arterial (SaO2) de 100% em ar ambiente. A indução da anestesia se processou com propofol 70 mg, fentanil 200 µg e rocurônio 45 mg. Após a intubação traqueal, diagnosticou-se quadro de anafilaxia que não respondeu ao tratamento convencional. Optou-se pelo uso de sugamadex 700 mg por via venosa como agente coadjuvante. A paciente apresentou reversão do quadro com melhora do perfil hemodinâmico sendo operada e conduzida à unidade de terapia intensiva. CONCLUSÃO: Neste caso, o sugamadex foi utilizado para reverter quadro hemodinâmico induzido pela anafilaxia por rocurônio, entretanto não foi possível esclarecer qual o mecanismo exato para a reversão do quadro hemodinâmico.

BACKGROUND AND OBJECTIVES: Anaphylaxis during anesthesia is a rare event that may occur in up to 1:20,000 cases and approximately 60% to 70% of these cases are secondary to the use of muscle relaxants, particularly succinylcholine and rocuronium. The aim of this report is to describe the treatment of a case of rocuronium-induced anaphylaxis with inadequate response to traditional therapy, and the case resolution after using sugammadex. CASE REPORT: A female patient, 62 years old, 72 kg, was referred to the surgical center for treatment of epidural hematoma following an accident at home. She was monitored with pulse oximetry, cardioscope, and blood pressure meter for non-invasive blood pressure (BP) measurement. The baseline data were: BP 138/80 mm Hg, heart rate (HR) 80 bpm, and oxygen saturation (SaO2) 100% on room air. Anesthesia was induced with propofol 70 mg, fentanyl 200 mg, and rocuronium 45 mg. After tracheal intubation, anaphylaxis non-responsive to conventional treatment was diagnosed. We chose the use of sugammadex 700 mg intravenously as an adjuvant agent. The patient had reversal of the anaphylactic reactions with improvement of hemodynamic profile and was operated and conducted to the intensive care unit. CONCLUSION: In this case, sugammadex was used to reverse the hemodynamic picture caused by rocuronium-induced anaphylaxis. However, it was not possible to identify the exact mechanism for the reversal.

JUSTIFICATIVA Y OBJETIVOS: La anafilaxia durante la anestesia es un evento raro que puede ocurrir hasta en 1: 20.000 casos siendo que aproximadamente entre un 60% a un 70% de ellos son secundarios al uso de relajantes musculares donde los más implicados son la succinilcolina y el Rocuronio. El objetivo de este relato, fue describir el tratamiento de un caso de anafilaxia inducida por Rocuronio con una respuesta inadecuada a la terapia tradicional y la solución del caso después del uso del sugamadex. RELATO DEL CASO: Paciente del sexo femenino, 62 años, 72 kg, derivada al quirófano para tratamiento de hematoma extradural posterior a accidente en domicilio. Fue monitorizada con oxímetro de pulso, cardioscopio y tensiómetro para la medida de la presión arterial no invasiva (PA). Sus datos basales fueron los siguientes: PA de 138/80 mm Hg, frecuencia cardíaca (FC) de 80 lpm y saturación arterial (SaO2) de 100% en aire ambiente. La inducción de la anestesia fue procesada con propofol 70 mg, fentanil 200 µg y Rocuronio 45 mg. Después de la intubación traqueal se diagnosticó un cuadro de anafilaxia que no respondió al tratamiento convencional. Optamos entonces por el uso del sugamadex 700 mg por vía venosa como agente coadyuvante. La paciente presentó una reversión del cuadro con una mejoría del perfil hemodinámico siendo operada y derivada a la unidad de cuidados intensivos. CONCLUSIONES: En este caso, el sugamadex fue utilizado para revertir el cuadro hemodinámico inducido por la anafilaxia por Rocuronio, pero no se pudo aclarar cuál sería el mecanismo exacto para la reversión del cuadro hemodinámico.

Application of different priming dose of muscle relaxant in endotracheal intubation and general anesthesia / 中国医师杂志

ObjectiveTo study the effects of different priming dose of muscle relaxant at the onset and endotracheal intubation conditions.Methods120 ASA Ⅰ～Ⅱ grade patients were randomly divided into 6 groups (n=6),vecuronium group (V 1,V2,V3) and cis-atrscurium group (C1,C2,C3).All patients were induced with propofol plasma (TCI)3 μg/ml,fentanil3 μg/kg.The V1 and C1 group were not given priming dose,and the V2,V3,C2,C3 groups were given priming dose of 10 μg/kg,20 μg/kg vecuronium and 15 μg/kg,30 μg/kg cis-atracurium.Intubating conditions were evaluated,and the onset time was monitored with train-of-four (TOF) technique.ResultsIntubating conditions were excellent in all patients.The onset time of priming groups of the four different doses was significantly shorter than that of the nonpriming group [(80.5±7.2) vs (146±10.7);(79.8±6.5) vs (146±10.7);(138.5±7.2) vs (218±10.7) ; (127.1±6.5) vs (218±10.7),P ＜ 0.05 ].ConclusionsThe taking-effect time of priming dose of muscle relaxant was significantly shorter than that of the nonpriming dose group.Increasing the priming dose not decrease onset time more than the smaller dose.

Anestesia para cesariana em paciente com siringomielia lombar / Anaesthesia for caesarean section in a patient with lumbar syringomyelia / Anestesia para cesárea en paciente con siringomielia lumbar

JUSTIFICATIVA E OBJETIVOS: Siringomielia é uma condição neurológica incomum caracterizada pela presença de uma cavidade cística expansiva na medula espinhal, resultando em várias manifestações neurológicas. O objetivo deste relato de caso é destacar a segurança da anestesia geral nesse grupo de pacientes. RELATO DO CASO: Primigesta de 28 anos, com diagnóstico de siringomielia lombar, foi programada para cirurgia de cesareana (CC). A cirurgia foi realizada sob anestesia geral, sem complicações. A anestesia geral foi escolhida no caso dessa paciente para evitar qualquer manipulação do espaço subaracnoideo no bloqueio do neuroeixo central, o que poderia levar a alterações da pressão intracraniana ou agravamento de sintomas neurológicos. Foi utilizado rocurônio, considerando que evita aumento de pressão no líquido cefalorraquidiano e hipercalemia, que podem ser vistos com succinilcolina. CONCLUSÕES: A anestesia geral pode ser usada com segurança em pacientes portadores de siringomielia. Devem-se tomar precauções para evitar aumento da pressão intracraniana e o bloqueio neuromuscular deve ser monitorado.

BACKGROUND AND OBJECTIVE: Syringomyelia is a rare neurological condition characterized by the presence of an expansive cystic cavity in the spinal cord, resulting in several neurologic manifestations. The objective of the present report was to address the safety of general anesthesia in this group of patients. CASE REPORT: This is a 28-year old primipara with lumbar syringomyelia scheduled for lower segment cesarean section (LSC). Surgery was performed under general anesthesia without complications. General anesthesia was chosen for this patient to avoid manipulation of the subarachnoid space during neuraxial anesthesia, which could cause changes in intracranial pressure or worsening neurological symptoms. We used rocuronium considering that it avoids rising in cerebrospinal fluid pressure and hyperkalemia that can be seen with succinylcholine. CONCLUSIONS: General anesthesia can be safely used in patients with syringomyelia. Care should be taken to prevent increase in intracranial pressure and neuromuscular blockade should be monitored.

JUSTIFICATIVA Y OBJETIVOS: La Siringomielia es una condición neurológica poco frecuente y caracterizada por la presencia de una cavidad cística expansiva en la médula espinal, resultando en varias manifestaciones neurológicas. El objetivo de este artículo es destacar la seguridad de la anestesia general en ese grupo de pacientes. RELATO DEL CASO: Primípara de 28 años, con diagnóstico de siringomielia lumbar, que fue programada para la cirugía de cesárea (CC). La cirugía fue realizada bajo anestesia general, sin complicaciones. La anestesia general fue elegida, en el caso de esa paciente, para evitar cualquier manipulación del espacio subaracnoide durante el bloqueo del neuro eje central, lo que podría conllevar a alteraciones de la presión intracraneana o al empeoramiento de los síntomas neurológicos. Se usó el rocuronio, al considerar que evita el aumento de la presión en el líquido cefalorraquídeo y la hipercalemia, que puede ser vista con la succinilcolina. CONCLUSIONES: La anestesia general puede ser usada con seguridad en pacientes portadores de siringomielia. Debemos tomar precauciones para evitar el aumento de la presión intracraneana y el bloqueo neuromuscular debe ser monitorizado.

Efeito da utilização de 2 mg. kg-1 de lidocaína endovenosa na latência de duas doses diferentes de rocurônio e na resposta hemodinâmica à intubação traqueal / Effects of 2 mg. kg-1 of intravenous lidocaine on the latency of two different doses of rocuronium and on the hemodynamic response of orotracheal intubation / Efecto de la utilización de 2 mg. kg-1 de lidocaína endovenosa en la latencia de dos dosis diferentes de rocuronio y en la respuesta hemodinámica a la intubación traqueal

JUSTIFICATIVA E OBJETIVOS: A lidocaína potencializa o efeito dos bloqueadores neuromusculares e atenua a resposta hemodinâmica à intubação. O objetivo do presente estudo foi testar o efeito da lidocaína sobre a latência de duas doses diferentes do rocurônio e sobre a resposta hemodinâmica à intubação orotraqueal (IOT). MÉTODO: 80 pacientes foram distribuídos em quatro grupos: os dos Grupos 1 e 2 receberam 0,6 mg.kg-1 de rocurônio, sendo que os do Grupo 2 receberam também 2 mg.kg-1 de lidocaína antes da indução; os dos Grupos 3 e 4 receberam 1,2 mg.kg-1 de rocurônio, sendo que os do Grupo 4 receberam 2 mg.kg-1 de lidocaína. A latência do bloqueio neuromuscular foi medida por meio da aceleromiografia. A avaliação hemodinâmica foi feita no momento basal, imediatamente antes e um minuto depois da IOT. RESULTADOS: Não se encontrou diferença estatística significativa entre a latência do rocurônio nas doses de 0,6 mg.kg-1 e 1,2 mg.kg-1 nos pacientes que receberam ou não a lidocaína antes da indução. A latência dos pacientes que receberam rocurônio 0,6 mg.kg-1 com lidocaína foi estatisticamente igual à dos pacientes que receberam 1,2 mg.kg-1de rocurônio, independentemente da administração ou não de lidocaína. Os pacientes que não receberam lidocaína antes da indução apresentaram aumento dos valores de pressão arterial sistólica, diastólica e média e da frequência cardíaca após a IOT, o que não ocorreu nos que receberam lidocaína. CONCLUSÕES: Assim, a lidocaína por via venosa antes da indução anestésica foi capaz de atenuar a resposta hemodinâmica associada às manobras de IOT, mas não de diminuir a latência do bloqueio neuromuscular produzido por duas doses diferentes de rocurônio.

BACKGROUND AND OBJECTIVES: Lidocaine potentiates the effects of neuromuscular blockers and attenuates the hemodynamic response to orotracheal intubation. The objective of the present study was to test the effects of lidocaine on the latency of two different doses of rocuronium and on the hemodynamic response to intubation. METHODS: Eighty patients were distributed in 4 groups: Groups 1 and 2 received 0.6 mg.kg-1 of rocuronium; patients in Group 2 also received 2 mg.kg-1 of lidocaine before intubation. Patients in Groups 3 and 4 received 1.2 mg.kg-1 of rocuronium; patients in Group 4 received additional 2 mg.kg-1 of lidocaine. The latency of the neuromuscular blockade was measured by acceleromyography. Hemodynamic evaluation was performed at baseline, immediately before, and 1 minute after orotracheal intubation (OI). RESULTS: Statistically significant differences were not observed between the latency from 0.6 mg.kg-1 and 1.2 mg.kg-1 of rocuronium in patients who received lidocaine before induction and those who did not. The latency in patients who received 0.6 mg.kg-1 of rocuronium with lidocaine was statistically similar to that of those who received 1.2 mg.kg-1 rocuronium independently of whether lidocaine was administered or not. Patients who did not receive lidocaine before induction showed the same increases in systolic, diastolic, and mean arterial pressure and heart rate after OI, which was not observed in those patients who received lidocaine. CONCLUSIONS: Intravenous lidocaine before anesthetic induction was capable of attenuating the hemodynamic response associated to OI maneuvers, but it did not reduce the latency of the neuromuscular blockade produced by two different doses of rocuronium.

JUSTIFICATIVA Y OBJETIVOS: La lidocaína potencia el efecto de los bloqueantes neuromusculares y atenúa la respuesta hemodinámica a la intubación. El objetivo del presente estudio fue comprobar el efecto de la lidocaína sobre la latencia de dos dosis diferentes del rocuronio y sobre la respuesta hemodinámica a la intubación. MÉTODO: 80 pacientes fueron distribuidos en 4 grupos: los dos Grupos 1 y 2 recibieron 0,6 mg.kg-1 de rocuronio, siendo que los del Grupo 2 recibieron también 2 mg.kg-1 de lidocaína antes de la inducción; los dos Grupos 3 y 4 recibieron 1,2 mg.kg-1 de rocuronio siendo que los del Grupo 4 recibieron 2 mg.kg-1 de lidocaína. La latencia del bloqueo neuromuscular se midió por medio de la aceleromiografía. La evaluación hemodinámica se hizo en el momento basal, inmediatamente antes y un minuto después de la IOT. RESULTADOS: No se encontró diferencia estadística significativa entre la latencia del rocuronio en las dosis de 0,6 mg.kg-1 y 1,2 mg.kg-1 en los pacientes que recibieron o no la lidocaína antes de la inducción. La latencia de los pacientes que recibieron rocuronio 0,6 mg.kg-1 con lidocaína fue estadísticamente igual a la de los pacientes que recibieron 1,2 mg.kg-1de rocuronio, independientemente de la administración o no de lidocaína. Los pacientes que no recibieron lidocaína antes de la inducción, presentaron aumentos de los valores de presión arterial sistólica, diastólica y promedio, y de la frecuencia cardíaca después de la IOT, pero eso no se dio en los que recibieron la lidocaína. CONCLUSIONES: Así, la lidocaína por vía venosa antes de la inducción anestésica fue capaz de atenuar la respuesta hemodinámica asociada a las maniobras de IOT, pero no de reducir la latencia del bloqueo neuromuscular producido por dos dosis diferentes de rocuronio.

Acurácia diagnóstica, análise da decisão e heurísticas relacionadas à decisão clínica intuitiva de usar antagonista de bloqueador neuromuscular / Diagnostic accuracy, decision analysis and heuristics related to the clinical intuitive decision of using antagonist of neuromuscular blocking agents

INTRODUÇÃO: A curarização residual está associada a maior risco de morte após anestesia. Erros diagnósticos após o uso de bloqueador neuromuscular (BNM) estão relacionados com prevalência de 65-88% de curarização residual pré-extubação traqueal (CRPE). Esse estudo analisou a decisão clínica intuitiva de usar antagonista de BNM antes da extubação traqueal. MÉTODOS: Após aprovação do Comitê de Ética em Pesquisa, a decisão clínica dos anestesiologistas da nossa instituição foi auditada em 150 pacientes. A participação foi voluntária e anônima. As decisões, como se fossem resultados de um teste diagnóstico, foram comparadas à aceleromiografia, com TOF < 0,9 definido como CRPE. Uma árvore de decisão foi estruturada para comparar as diferentes estratégias e uma pesquisa sequencial (Delphi), realizada entre 108 anestesiologistas, extraiu as heurísticas (regras simplificadoras) mais usadas. RESULTADOS: A prevalência de CRPE foi de 77%. A intuição clínica apresentou sensibilidade de 0,35 (0,23-0,49) e especificidade de 0,80 (0,54- 0,94) para CRPE (P= 0,0001). Em uma escala de 0-10 a utilidade esperada da intuição foi menor do que sempre antagonizar (4,1 + 4,4 vs. 8,4 + 3,0, P< 0,05). As heurísticas mais proeminentes foram O intervalo desde a última dose de BNM foi curto e O padrão respiratório está inadequado, citadas por 73% e 71% dos anestesiologistas, respectivamente. Uma hora após dose única de atracúrio comparada ao rocurônio, 69,3% vs. 47,1% (P= 0,0035) dos anestesiologistas não usam antagonista antes da extubação traqueal. Os anestesiologistas têm a percepção de que a prevalência de curarização residual clinicamente significativa é maior na prática dos seus colegas do que na sua própria prática clínica (razão de chances 7,8 (3,8-16,2) P< 0,0001). CONCLUSÕES: A intuição clínica não deve ser usada para descartar a presença de curarização residual. Sempre usar o antagonista é uma estratégia melhor do que usar a intuição clínica para decidir...

BACKGROUND: Residual curarization is associated with a higher risk of death after anesthesia. Diagnostic errors after the use of neuromuscular blocking agents (NMBA) are related to 65-88% prevalence of preextubation residual curarization (PERC). This study analyzed the clinical intuitive decision of antagonizing NMBA before tracheal extubation. METHODS: After IRB approval, this clinical decision was audited in 150 patients. Participation in the study was voluntary and anonymous. Decisions, as if a diagnostic test, were compared to acceleromyography, with TOF<0.9 defined as PERC. A decision tree was structured to compare different decision strategies. A sequential survey (Delphi) was conducted among 108 anaesthesiologists to elicit the most frequently used heuristics (rules of thumb). RESULTS: PERC prevalence was 77%. Clinical intuition presented sensitivity of 0.35 (0.23-0.49) and specificity of 0.80 (0.54-0.94) (P=0.0001). In a 0-10 rating scale, expected utility of intuition was lower than always antagonize all patients (4.1 + 4.4 vs. 8.4 + 3.0, P<0.05). The most salient heuristics were Short interval since the last NMBA dose and Breathing pattern is inadequate stated by 73% and 71% of the anesthesiologists, respectively. One hour after a single dose of atracurium compared with rocuronium, 69.3% vs. 47.1% (P= 0.0035) of the anesthesiologists do not use antagonist before tracheal extubation. They perceive that prevalence of clinically significant residual curarization is higher in their colleagues practice than in their own clinical practice (odds ratio 7.8 (3.8- 16.2), P< 0.0001). CONCLUSIONS: Clinical intuition should not be used to rule out residual curarization. Routine antagonism is a better strategy than the use of clinical intuition to make this decision. Clinicians make this intuitive decision based on a forecast of the duration of the effects of NMBA and on a qualitative judgement about the adequacy of the patients breathing...

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.

Comparison of pharmacodynamics of rocuronium administered by continuous infusion versus intermittent bolus injection / 中华麻醉学杂志

Objective The study was designed to compare the pharmacodynamics of rocuronium administered by continuous infusion and intermittent bolus injection Methods Fifty ASAⅠ Ⅱ patients without any neuromuscular disease undergoing elective surgery under general anesthesia were randomly divided into two groups of 25 patients each In groupⅠ patients received rocuronium by intermittent bolus injection and in group Ⅱ by continuous infusion The responses of adductor pollicis to train of four (TOF) stimulation of ulnar nerve were monitored The onset time, the time of maximal neuromuscular blockade, the spontaneous recovery from paralysis and the total dose of rocuronium were recorded Intravenous anesthesia was used for both induction and maintenance of anesthesia, no patient received reversal of block Neuromuscular blockade monitoring ended when TOF ratio(T 4/T 1)≥70% The patients were extubated when ventilation was satisfactory Results The two groups were comparable with regard to age, sex, weight and duration of operation The mean onset time after rocuronium bolus(0 6mg/kg) was (78 18?15 44) s In group Ⅱ the mean infusion rate was (6 31?1 93)?g?kg -1 ?min -1 which was not significantly different from the amount of rocuronium administered per minute (5 43?1 46)?g?kg -1 ?min -1 in groupⅠ The mean interval between two bolus injection in group Ⅰwas (29 24?6 26) min, and no significant difference was seen between intervals The spontaneous recovery from neuromuscular block was significantly faster in group Ⅱ than that in group Ⅰ Conclusions Rocuronium has no cumulative effect There was no significant difference in the amount of rocuronium administered per unit time between the two groups The spontaneous recovery from neuromuscular block is faster by continuous infusion than that by intermittent bolus injection