The case report by Bauer et al. highlights that problems occur following rapid sequence induction (RSI) and may lead to invasive procedures.1 These can cause harm to the patient.
There are other lessons to be learnt that the authors have not elaborated upon.
The presence of fasciculations and flaccid paralysis following the first dose of suxamethonium indicated the onset of the expected effect.
Despite masseter spasm, the patient could be easily ventilated with a bag and mask. Subsequent deterioration in oxygenation after some time resulted in a surgical airway.
A significant learning point omitted from the authors' summary was the administration to this patient of a second dose of suxamethonium in the presence of masseter spasm. This should not have occurred for two reasons:
Masseter spasm is an early sign of malignant hyperpyrexia (MH), which has a mortality rate even with dantrolene of around 5%. Suxamethonium is a significant precipitant in susceptible individuals.
Repeated doses of suxamethonium change the paralysing effect of the drug from one that wears off within 3–5 minutes (“Phase I block”) to one resembling a non‐depolarising neuromuscular block (“Phase II block”) which lasts significantly longer. It has been long established that this type of block may begin at doses of 2 mg/kg.2
The appropriate action when unable to intubate, is to maintain oxygenation, call for experienced help and strongly consider terminating anaesthesia.3 In this case, the need for a surgical airway may well have been avoided.
Repeated doses of suxamethonium can disproportionately extend the duration of paralysis and may add to a developing, potentially fatal condition (MH) caused by the first dose.
The process of inducing anaesthesia and paralysis is not usually as difficult as dealing with the problems that may arise if things do not go smoothly. Practitioners should be aware of the adverse effects of drugs they are using and be able to instigate appropriate methods of dealing with problems before undertaking RSI.
References
- 1.Bauer S J, Orio K, Adams B D. Succinylcholine induced masseter spasm during rapid sequence intubation may require a surgical airway: case report. Emerg Med J 200522456–458. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Lee C. Dose relationships of phase II, tachyphylaxis and train‐of‐ four fade in suxamethonium‐induced dual neuromuscular block in man. Br J Anaesth Aug 197547841–845. [DOI] [PubMed] [Google Scholar]
- 3.Difficult Airway Society guidelines for management of the unanticipated difficult intubation. Henderson J J, Popat M T, Latto I P, Pearce A C ; Difficult Airway Society. Anaesthesia. 2004 Jul 59(7)675–694. [DOI] [PubMed] [Google Scholar]