Anaesthetic management in patients with Duchenne muscular dystrophy

Editor, After reading the very informative article by Muenster et al.1 on the anaesthetic management of patients with Duchenne muscular dystrophy, some questions remain. First, this is an interesting case series because of the large number of general anaesthesia episodes included (232 in 191 Duchenne muscular dystrophy patients) and because 79 procedures were for corrective spinal fusion. This type of surgery can severely affect the immediate respiratory recovery of these patients as shown by the exclusive need of postoperative ventilatory support in the group with spinal fusion.1 Related to this aspect is the use of neuromuscular blocking agents. However, perhaps due to space restrictions in the journal, only the type of neuromuscular blocking agent and the type of monitoring (acceleromyography) were stated, together with the crude number of patients receiving it. However, in the discussion section, the topic is addressed in depth. Due to the variability in the response to neuromuscular blocking agent in patients with neuromuscular diseases, some general recommendations have been made and shall be briefly reported here.2,3 An individual evaluation of a patient's characteristics should be made and early extubation should be attempted. Reversal of neuromuscular blockade with neostigmine should be avoided; provided rocuronium was used, sugammadex has become – in our opinion – the drug of choice. A train-of-four ratio of 0.9 should be aimed for to guarantee a complete recovery of the diaphragm (despite the fact that the neurophysiologic conditions of the neuromuscular transmission in these patients, and the electrophysiological characteristics of both muscles and stimuli used, need to be improved in the future4). It is equally important to check for adequate coughing and swallowing before extubation, and to evaluate respiratory parameters (inspiratory force −20 cmH2O, vital capacity 1000 ml, PaO2 250 mmHg with O2 inspiratory fraction of 1, considering preoperative values). The variability in the onset of the neuromuscular block, which is usually delayed, and the prolonged duration were underlined by the authors.1 Although the authors support the use of pyridostigmine for the reversal of the neuromuscular block, the number of cases that were reversed with this drug was not shown, nor was the success of the reversal, or how many patients needed respiratory postoperative support in whom reversal was attempted. In addition, the adequacy of using sugammadex was shown in several case reports in patients with Duchenne muscular dystrophy5 and Becker muscular dystrophy,6 which is a minor form of the disease. Thus, it would be interesting to know whether the authors have any experience with reversal with sugammadex in these patients. Addressing the effects of anaesthesia or anaesthetic drugs in patients with rare diseases (so-called ‘orphan diseases’) is often only possible in case reports or case series. Recently, several cases of successful reversal of neuromuscular blocking agents with sugammadex have been reported in the European Journal of Anaesthesiology, suggesting the adequacy and safety of that drug in patients with further rare neuromuscular diseases such as myotonic dystrophy,7 or Huntington's chorea.8 Muenster et al.1 have reported on the successful anaesthetic management in a large sample of patients with Duchenne muscular dystrophy. In these patients, who are at risk for severe postoperative problems, all anaesthesiological knowledge and armamentarium should be used. Acknowledgements Assistance with the letter: none declared. Financial support and sponsorship: none declared. Conflicts of interest: CLE has received payments for lectures and meeting expenses from Organon española, Schering-Plough Spain and MSD Spain. PPC has received payments for meeting expenses from MSD Spain.