Use of protocol and evaluation of postoperative residual curarization incidence in the absence of intraoperative acceleromyography - Randomized clinical trial / Aplicação de protocolo e avaliação da incidência de curarização residual pós-operatória na ausência de aceleromiografia intraoperatória - Ensaio clínico randomizado

Abstract Objective Evaluate the incidence of postoperative residual curarization (PORC) in the post-anesthesia care unit (PACU) after the use of protocol and absence of intraoperative acceleromyography (AMG). Methods Randomized clinical trial with 122 patients allocated into two groups (protocol and control). Protocol group received initial and additional doses of rocuronium (0.6 mg·kg-1 and 10 mg, respectively); the use of rocuronium was avoided in the final 45 min; blockade reversal with neostigmine (50 µg·kg-1); time ≥15 min between reversion and extubation. Control: initial and additional doses of rocuronium, blockade reversal, neostigmine dose, and extubation time, all at the discretion of the anesthesiologist. AMG was used in the PACU and PORC considered at T4/T1 ratio <1.0. Results The incidence of PORC was lower in protocol group than in control group (25% vs. 45.2%, p = 0.02). In control group, total dose of rocuronium was higher in patients with PORC than without PORC (0.43 vs. 0.35 mg·kg-1·h-1, p = 0.03) and the time interval between the last administration of rocuronium and neostigmine was lower (75.0 vs. 101.0 min, p < 0.01). In protocol group, there was no difference regarding the analyzed parameters (with PORC vs. without PORC). Considering the entire study population and the presence or absence of PORC, total dose of rocuronium was higher in patients with PORC (0.42 vs. 0.31 mg·kg-1·h-1, p = 0.01), while the time interval between the last administration of rocuronium and neostigmine was lower (72.5 vs. 99.0 min, p ≤ 0.01). Conclusion The proposed systematization reduced PORC incidence in PACU in the absence of intraoperative AMG.

Resumo Objetivo Avaliou-se a incidência de curarização residual pós-operatória (CRPO) na sala de recuperação pós-anestésica (SRPA) após emprego de protocolo e ausência de aceleromiografia (AMG) intraoperatória. Métodos Ensaio clínico, aleatório, com 122 pacientes, distribuídas em dois grupos: protocolo e controle. Protocolo: dose inicial e adicionais de rocurônio foram de 0,6 mg.kg-1 e 10 mg, respectivamente; evitou-se o uso de rocurônio nos 45 minutos finais; reversão do bloqueio com neostigmina (50 µg.kg-1); tempo ≥ 15 minutos entre reversão e extubação. Controle: doses inicial e adicional de rocurônio, reversão do bloqueio, dose de neostigmina e momento da extubação decididos pelo anestesiologista. Foi usada AMG na SRPA e considerado CRPO razão T4/T1 < 1,0. Resultados A incidência de CRPO foi menor no grupo protocolo em relação ao controle (25% vs. 45,2%; p = 0,02). No grupo controle, a dose total de rocurônio foi maior em pacientes com CRPO em relação àqueles sem CRPO (0,43 vs. 0,35 mg.kg-1.h-1; p = 0,03) e o intervalo entre a última administração de rocurônio e a neostigmina foi menor (75,0 vs. 101,0 min; p < 0,01). No grupo protocolo não houve diferença dos parâmetros analisados (com CRPO vs. sem CRPO). Considerando toda a população de estudo e a presença ou não de CRPO, a dose total de rocurônio foi maior em pacientes com CRPO (0,42 vs. 0,31 mg.kg-1.h-1; p = 0,01), enquanto o intervalo entre a última administração de rocurônio e a neostigmina foi menor (72,5 vs. 99,0 min; p ≤ 0,01). Conclusão A sistematização proposta reduziu a incidência de CRPO na SRPA na ausência de AMG intraoperatória.

Use of neuromuscular blockers and neostigmine for general anesthesia and its association with neuraxial blockade: A retrospective study.

This research aimed to assess the use of neuromuscular blockers (NMB) and its reversal, associated or not with neuraxial blockade, after general anesthesia.This retrospective study analyzed 1295 patients that underwent surgery with general anesthesia at Prof. Dr. José Aristodemo Pinotti Hospital in 2013. The study included patients aged >1 year, with complete, readable medical charts and anesthetic records.Rocuronium (ROC) was the most used NMB (96.7%), with an initial dose of 0.60 (0.52-0.74) mg/kg and total dose of 0.38 (0.27-0.53) mg/kg/h. In 24.3% of the cases, neuraxial blockade was associated with a significantly longer anesthesia (P < .001) than in cases without neuraxial block, regardless of technique (total intravenous (TIV) vs intravenous and inhalational (IV+IN)). In 71.9% of the cases, a single dose of NMB was used. Patients under TIV general anesthesia associated with neuraxial blockade had a lower total dose of ROC (mg/kg/h) in comparison with TIV GA alone (0.30 (0.23-0.39) and 0.42 (0.30-0.56) mg/kg/h, respectively, P < .001). The same was observed for patients under IV+IN GA (0.32 (0.23-0.41) and 0.43 (0.31-0.56) mg/kg/h, respectively, P < .001). The duration of anesthesia was longer according to increasing number of additional NMB doses (P < .001). Dose of neostigmine was 2.00 (2.00-2.00) mg or 29.41 (25.31-33.89) µg/kg. The interval between neostigmine and extubation was >30 minutes in 10.9% of cases.The most widely used NMB was ROC. Neuroaxial blockade (spinal or epidural) was significantly associated with reduced total dose of ROC (mg/kg/h) during general anesthesia, even in the absence of neuromuscular monitoring and regardless of general anesthetic technique chosen. In most cases, neostigmine was used to reverse neuromuscular block. The prolonged interval between neostigmine and extubation (>30 minutes) was neither associated with total doses of ROC or neostigmine, nor with the time of NMB administration. This study corroborates the important role of quantitative neuromuscular monitors and demonstrates that neuraxial blockade is associated with reduced total ROC dose. Further studies are needed to evaluate the possible role of neuraxial blockade in reducing the incidence of postoperative residual curarization.

[Use of protocol and evaluation of postoperative residual curarization incidence in the absence of intraoperative acceleromyography - Randomized clinical trial]. / Aplicação de protocolo e avaliação da incidência de curarização residual pós­operatória na ausência de aceleromiografia intraoperatória ­ Ensaio clínico randomizado.

OBJECTIVE: Evaluate the incidence of postoperative residual curarization (PORC) in the post-anesthesia care unit (PACU) after the use of protocol and absence of intraoperative acceleromyography (AMG). METHODS: Randomized clinical trial with 122 patients allocated into two groups (protocol and control). Protocol group received initial and additional doses of rocuronium (0.6mg.kg-1 and 10mg, respectively); the use of rocuronium was avoided in the final 45minutes; blockade reversal with neostigmine (50µg.kg-1); time ≥ 15minutes between reversion and extubation. CONTROL: initial and additional doses of rocuronium, blockade reversal, neostigmine dose, and extubation time, all at the discretion of the anesthesiologist. AMG was used in the PACU and PORC considered at T4/T1 ratio<1.0. RESULTS: The incidence of PORC was lower in protocol group than in control group (25% vs. 45.2%, p=0.02). In control group, total dose of rocuronium was higher in patients with PORC than without PORC (0.43 vs. 0.35mg.kg-1.h-1, p=0.03) and the time interval between the last administration of rocuronium and neostigmine was lower (75.0 vs. 101.0min, p<0.01). In protocol group, there was no difference regarding the analyzed parameters (with PORC vs. without PORC). Considering the entire study population and the presence or absence of PORC, total dose of rocuronium was higher in patients with PORC (0.42 vs. 0.31mg.kg-1.h-1, p=0.01), while the time interval between the last administration of rocuronium and neostigmine was lower (72.5 vs. 99.0min, p ≤ 0.01). CONCLUSION: The proposed systematization reduced PORC incidence in PACU in the absence of intraoperative AMG.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Evidence of presynaptic and postsynaptic action of local anesthetics in rats

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