Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Original Investigation

Comparison of onset of neuromuscular blockade with electromyographic and acceleromyographic monitoring: a prospective clinical trial

Comparação do início do bloqueio neuromuscular com monitoração eletromiográfica e aceleromiográfica: um ensaio clínico prospectivo

Harold E. Chaves-Cardona, Eslam A. Fouda, Vivian Hernandez-Torres, Klaus D. Torp, Ilana I. Logvinov, Michael G. Heckman, Johnathan Ross Renew

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Reliable devices that quantitatively monitor the level of neuromuscular blockade after neuromuscular blocking agents’ administration are crucial. Electromyography and acceleromyography are two monitoring modalities commonly used in clinical practice. The primary outcome of this study is to compare the onset of neuromuscular blockade, defined as a Train-Of-Four Count (TOFC) equal to 0, as measured by an electromyography-based device (TetraGraph) and an acceleromyography-based device (TOFscan). The secondary outcome was to compare intubating conditions when one of these two devices reached a TOFC equal to 0.


One hundred adult patients scheduled for elective surgery requiring neuromuscular blockade were enrolled. Prior to induction of anesthesia, TetraGraph electrodes were placed over the forearm of patients’ dominant/non-dominant hand based on randomization and TOFscan electrodes placed on the contralateral forearm. Intraoperative neuromuscular blocking agent dose was standardized to 0.5−1 of rocuronium. After baseline values were obtained, objective measurements were recorded every 20 seconds and intubation was performed using video laryngoscopy once either device displayed a TOFC = 0. The anesthesia provider was then surveyed about intubating conditions.


Baseline TetraGraph train-of-four ratios were higher than those obtained with TOFscan (Median: 1.02 [0.88, 1.20] vs. 1.00 [0.64, 1.01], respectively, p < 0.001). The time to reach a TOFC = 0 was significantly longer when measured with TetraGraph compared to TOFscan (Median: 160 [40, 900] vs. 120 [60, 300] seconds, respectively, p < 0.001). There was no significant difference in intubating conditions when either device was used to determine the timing of endotracheal intubation.


The onset of neuromuscular blockade was longer when measured with TetraGraph than TOFscan, and a train-of-four count of zero in either device was a useful indicator for adequate intubating conditions.



Accelerometry, Electromyography, Intubation, Neuromuscular blockade, Neuromuscular junction, Intraoperative neurophysiological monitoring



Dispositivos confiáveis que monitoram quantitativamente o nível de bloqueio neuromuscular após a administração de agentes bloqueadores neuromusculares são cruciais. A eletromiografia e a aceleromiografia são duas modalidades de monitoramento comumente utilizadas na prática clínica. O resultado primário deste estudo é comparar o início do bloqueio neuromuscular, definido como uma contagem de trem de quatro (TOFC) igual a 0, conforme medido por um dispositivo baseado em eletromiografia (TetraGraph) e um dispositivo baseado em aceleromiografia (TOFscan ). O desfecho secundário foi comparar as condições de intubação quando um desses dois dispositivos atingiu um TOFC igual a 0.


Cem pacientes adultos agendados para cirurgia eletiva que requerem bloqueio neuromuscular foram incluídos. Antes da indução da anestesia, os eletrodos TetraGraph foram colocados sobre o antebraço da mão dominante/não dominante dos pacientes com base na randomização e os eletrodos TOFscan foram colocados no antebraço contralateral. A dose intraoperatória do bloqueador neuromuscular foi padronizada para 0,5−1 de rocurônio. Depois que os valores basais foram obtidos, as medições objetivas foram registradas a cada 20 segundos e a intubação foi realizada usando videolaringoscopia uma vez que qualquer um dos dispositivos exibiu um TOFC = 0. O anestesista foi então questionado sobre as condições de intubação.


Os índices de linha de base de trem de quatro do TetraGraph foram superiores aos obtidos com TOFscan (mediana: 1,02 [0,88, 1,20] vs. 1,00 [0,64, 1,01], respetivamente, p < 0,001). O tempo para atingir um TOFC = 0 foi significativamente maior quando medido com TetraGraph em comparação com TOFscan (mediana: 160 [40, 900] vs. 120 [60, 300] segundos, respectivamente, p < 0,001). Não houve diferença significativa nas condições de intubação quando qualquer um dos dispositivos foi usado para determinar o momento da intubação endotraqueal.


O início do bloqueio neuromuscular foi mais longo quando medido com o TetraGraph do que com o TOFscan, e uma contagem de zero em sequência de quatro em qualquer um dos dispositivos foi um indicador útil para condições de intubação adequadas.


Acelerometria; Eletromiografia; Intubação; Bloqueio neuromuscular; Junção neuromuscular; Monitorização neurofisiológica intraoperatória


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