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Propofol reduces succinylcholine induced increase of masseter muscle tone



Succinylcholine is known to increase the tone of the masseter muscles. As excessive jaw tension may complicate rapid sequence induction, we investigated three induction techniques, all including the use of succinylcholine, with respect to masseter muscle tone, neuromuscular blockade, intubation conditions, and time course of intubation.


Sixty adult patients were allocated to one of three induction groups: Group THIO received 5 mg · kg−1 thiopentone, Group THIO/ATR received 5 mg · kg−1 thiopentone plus 0.05 mg · kg−1 atracurium for precurarization, and Group PROP received 2.5 mg · kg−1 propofol. All patients received 3 μg · kg−1 fentanyl and 1.5 mg · kg−1 succinylcholine. Time for induction of anaesthesia was recorded, and, after inserting a Grass Force Transducer between upper and lower incisors, jaw tone and the time course of jaw tension was recorded before and after the administration of succinylcholine.


No differences in the onset of sleep were observed among the three groups (Group THIO 33 ± 2 sec: THIO/ATR 30 ± 2 sec: PROP 35± 2 sec, mean ± SE). Masseter preloads following induction of anaesthesia were similar in all three groups (THIO 16.4 ± 2.1 N: THIO/ATR 15.1 ± 2.0 N: PROP 12.7 ± 1.6 N). However, after administration of succinylcholine, the increase in masseter tone was less in Groups PROP (5.0 ±1.1 N) and THIO/ATR (6.4 ± 2.1 N) than in Group THIO (12.4 ± 3.0 N;P < 0.05).


Jaw tension after administration of succinylcholine is influenced by the choice of induction agent. The increase of masseter muscle tone is lower following propofol or thiopentone/atracurium induction than with thiopentone alone.



La succinylcholine est connue pour augmenter le tonus des muscles masséter. Comme une tension excessive sur la mâchoire peut compliquer une induction en séquence rapide, nous avons évalué trois techniques d’induction, incluant toutes de la succinylcholine, quant au tonus du masséter, au bloc neuromusculaire, aux conditions d’intubation et au délai de l’intubation.


Soixante patients adultes ont été répartis en trois groupes selon l’induction: le groupe THIO a reçu 5 mg · kg−1 de thiopental, le groupe THIO/ATR a reçu 5 mg · kg−1 de thiopental plus 0.05 mg · kg−1 d’atracurium comme précurarisation et le groupe PROP a reçu 2.5 mg · kg−1 de propofol. Tous les patients ont par ailleurs reçu 3 μg · kg−1 de fentanyl et 1.5 mg · kg−1 de succinylcholine. Le temps requis pour l’induction a été noté et, après insertion d’un dynamomètre Grass entre les incisives supérieures et inférieures, le tonus de la mâchoire et l’évolution dans le temps de cette tension ont été notés avant et après l’administration de succinylcholine.


Aucune différence n’a été observée entre les groupes concernant l’induction: le groupe THIO 33 ± 2 sec, le groupe THIO/ATR 30 ± 2 sec, le groupe PROP 35 ± 2 sec, moyenne ± ET La précharge des masséters suite à l’induction était la même dans les 3 groupes: THIO 16.4 ± 2.1 N, THIO/ATR 15.1 ± 2.0 N, PROP 12.7 1.6 N. Cependant, suite à l’administration de succinylcholine, l’augmentation du tonus des masséters était moindre dans les groupes PROP (5.0 ± 1.1 N) et THIO/ATR (6.4 ± 2.1 N) que dans le groupe THIO (12.4 ± 3.0 N; P 0.05).


La tension du maxillaire après l’administration de succinylcholine est influencée par le choix des agents d’induction. Laugmentation de tonus des masséters est moindre suite à une induction au propofol ou au thiopental/atracurium qu’au thiopental seul.


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Correspondence to Wolfgang C. Ummenhofer.

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Ummenhofer, W.C., Kindler, C., Tschalèr, G. et al. Propofol reduces succinylcholine induced increase of masseter muscle tone. Can J Anaesth 45, 417 (1998).

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  • Succinylcholine
  • Thiopentone
  • Neuromuscular Blockade
  • Atracurium
  • Masseter Muscle