title: Forces applied during laryngoscopy in children. Are volatile anaesthetics essential for suxamethonium induced muscle rigidity?
abstract: Increased masticatory muscle tone after administration of suxamethonium has been demonstrated in children when combined with volatile anaesthetics. Whether volatiles are a prerequisite for this phenomenon is not known. In this study upper airway muscle tone, including the tone of the masticatory muscles, was determined in 54 children (age range 2-15 years), anaesthetized with propofol, fentanyl and nitrous oxide and avoiding any use of volatiles. The children were either relaxed with suxamethonium (n = 26) or vecuronium (n = 28). The forces applied during laryngoscopy were used to quantify upper airway muscle tone and were significantly greater in the suxamethonium group than in the vecuronium group: maximally applied force was 25 N versus 21 N (P = 0.008), and mean applied force was 16 N versus 13 N (P = 0.006), respectively. The results of this study indicate that upper airway muscle tone increases after administration of suxamethonium in children independent of the presence of volatile anaesthetics. Moreover, increased muscle tone had no effect on the difficulty of laryngoscopy or the intubation conditions. Increased masseter muscle rigidity after suxamethonium could be due to the very unique characteristics of this muscle.
authors.affiliation: Department of Anaesthesia, Erasmus University, Rotterdam, The Netherlands.
authors.forename: M J
authors.initials: MJ
authors.lastname: Bucx
authors.forename: R T
authors.initials: RT
authors.lastname: Van Geel
authors.forename: A E
authors.initials: AE
authors.lastname: Meursing
authors.forename: T
authors.initials: T
authors.lastname: Stijnen
authors.forename: P A
authors.initials: PA
authors.lastname: Scheck
mesh_terms: D000293:Adolescent; D018685:Anesthetics, Inhalation / Q000009:adverse effects / Q000494:pharmacology*; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D003413:Cricoid Cartilage / Q000503:physiopathology; D004347:Drug Interactions; D005260:Female; D005283:Fentanyl / Q000009:adverse effects / Q000494:pharmacology; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation; D020704:Laryngoscopes; D007828:Laryngoscopy; D008297:Male; D008410:Masticatory Muscles / Q000187:drug effects / Q000503:physiopathology; D009127:Muscle Rigidity / Q000139:chemically induced* / Q000503:physiopathology; D009129:Muscle Tonus / Q000187:drug effects; D009609:Nitrous Oxide / Q000009:adverse effects / Q000494:pharmacology; D011312:Pressure; D015742:Propofol / Q000009:adverse effects / Q000494:pharmacology; D013390:Succinylcholine / Q000009:adverse effects / Q000494:pharmacology*; D014673:Vecuronium Bromide / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D014673:Vecuronium Bromide; D013390:Succinylcholine; D009609:Nitrous Oxide; D005283:Fentanyl; D015742:Propofol