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Contains fulltext : 287509.pdf (Publisher’s version ) (Open Access) BACKGROUND AND PURPOSE: Patients with neuromuscular conditions are at increased risk of suffering perioperative complications related to anaesthesia. There is currently little specific anaesthetic guidance concerning these patients. Here, we present the European Neuromuscular Centre (ENMC) consensus statement on anaesthesia in patients with neuromuscular disorders as formulated during the 259th ENMC Workshop on Anaesthesia in Neuromuscular Disorders. METHODS: International experts in the field of (paediatric) anaesthesia, neurology, and genetics were invited to participate in the ENMC workshop. A literature search was conducted in PubMed and Embase, the main findings of which were disseminated to the participants and presented during the workshop. Depending on specific expertise, participants presented the existing evidence and their expert opinion concerning anaesthetic management in six specific groups of myopathies and neuromuscular junction disorders. The consensus statement was prepared according to the AGREE II (Appraisal of Guidelines for Research & Evaluation) reporting checklist. The level of evidence has been adapted according to the SIGN (Scottish Intercollegiate Guidelines Network) grading system. The final consensus statement was subjected to a modified Delphi process. RESULTS: A set of general recommendations valid for the anaesthetic management of patients with neuromuscular disorders in general have been formulated. Specific recommendations were formulated for (i) neuromuscular junction disorders, (ii) muscle channelopathies (nondystrophic myotonia and periodic paralysis), (iii) myotonic dystrophy (types 1 and 2), (iv) muscular dystrophies, (v) congenital myopathies and congenital dystrophies, and (vi) mitochondrial and metabolic myopathies. CONCLUSIONS: This ENMC consensus statement summarizes the most important considerations for planning and performing anaesthesia in patients with neuromuscular disorders.

Malignant hyperthermia is a potentially fatal condition, in which genetically predisposed individuals develop a hypermetabolic reaction to potent inhalation anaesthetics or succinylcholine. Because of the rarity of malignant hyperthermia and ethical limitations, there is no evidence from interventional trials to inform the optimal perioperative management of patients known or suspected with malignant hyperthermia who present for surgery. Furthermore, as the concentrations of residual volatile anaesthetics that might trigger a malignant hyperthermia crisis are unknown and manufacturers' instructions differ considerably, there are uncertainties about how individual anaesthetic machines or workstations need to be prepared to avoid inadvertent exposure of susceptible patients to trigger anaesthetic drugs. The present guidelines are intended to bundle the available knowledge about perioperative management of malignant hyperthermia-susceptible patients and the preparation of anaesthesia workstations. The latter aspect includes guidance on the use of activated charcoal filters. The guidelines were developed by members of the European Malignant Hyperthermia Group, and they are based on evaluation of the available literature and a formal consensus process. The most crucial recommendation is that malignant hyperthermia-susceptible patients should receive anaesthesia that is free of triggering agents. Providing that this can be achieved, other key recommendations include avoidance of prophylactic administration of dantrolene; that preoperative management, intraoperative monitoring, and care in the PACU are unaltered by malignant hyperthermia susceptibility; and that malignant hyperthermia patients may be anaesthetised in an outpatient setting.

Malignant hyperthermia (MH) is a life-threatening reaction triggered by volatile anesthetics and succinylcholine. MH is caused by mutations in the skeletal muscle ryanodine receptor (RYR1) gene, as is rhabdomyolysis triggered by exertion and/or pyrexia. The discrepancy between the prevalence of risk genotypes and actual MH incidence remains unexplained. We investigated the role of pre-operative exercise and pyrexia as potential MH modifying factors. We included cases from 5 MH referral centers with 1) clinical features suggestive of MH, 2) confirmation of MH susceptibility on Contracture Testing (IVCT or CHCT) and/or RYR1 genetic testing, and a history of 3) strenuous exercise within 72 h and/or pyrexia >37.5 degrees C prior to the triggering anesthetic. Characteristics of MH-triggering agents, surgery and succinylcholine use were collected. We identified 41 cases with general anesthesias resulting in an MH event (GA+ MH, n = 41) within 72 h of strenuous exercise and/or pyrexia. We also identified previous general anesthesias without MH events (GA-MH, n = 51) in the index cases and their MH susceptible relatives. Apart from pre-operative exercise and/or pyrexia, trauma and acute abdomen as surgery indications, emergency surgery and succinylcholine use were also more common with GA+ MH events. These observations suggest a link between pre-operative exercise, pyrexia and MH. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Contains fulltext : 248839.pdf (Publisher’s version ) (Closed access)

Background The introduction of next-generation sequencing into the diagnosis of neuromuscular disorders has resulted in an increased number of newly identified RYR1 variants. The hypothesis was that there is an increased referral of patients to malignant hyperthermia units without a personal/family history of adverse anesthetic events suspected to be malignant hyperthermia. This retrospective multicenter cohort study evaluates patient referral indications and outcomes for those without a history of an adverse anesthetic event. Methods Patients referred between 2010 and 2019 to the malignant hyperthermia units in Antwerp, Belgium; Lund, Sweden; Nijmegen, The Netherlands; and Toronto, Ontario, Canada were included. Previously tested patients and relatives of previously tested patients were excluded. Data collection included demographics, referral details, muscle contracture, and genetic testing results including Rare Exome Variant Ensemble Learner scores. Referral indications were categorized into those with a personal/family history of adverse anesthetic event and other indications including exertional and/or recurrent rhabdomyolysis, RYR1 variant(s) detected in diagnostic testing in the neuromuscular clinic without a specific diagnosis (in a family member), diagnosed RYR1-related myopathy (in a family member), idiopathically elevated resting creatine kinase values, exertional heat stroke, and other. Results A total of 520 medical records were included, with the three most frequent referral indications as follows: personal history of an adverse anesthetic event (211 of 520; 40.6%), family history of an adverse anesthetic event (115 of 520; 22.1%), and exertional and/or recurrent rhabdomyolysis (46 of 520; 8.8%). The proportion of patients referred without a personal/family history of an adverse anesthetic event increased to 43.6% (133 of 305) between 2015 and 2019 compared to 28.4% (61 of 215) in 2010 to 2014 (P < 0.001). Patients with a personal/family history of an adverse anesthetic event were more frequently diagnosed as malignant hyperthermia–susceptible (133 of 220; 60.5%) than those without (47 of 120; 39.2%; P < 0.001). Due to missing data, 180 medical records were excluded. Conclusions The proportion of patients referred to malignant hyperthermia units without a personal/family history of an adverse anesthetic event has increased, with 39.2% (47 of 120) diagnosed as malignant hyperthermia–susceptible. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Background: Malignant Hyperthermia (MH) is a life-threatening reaction triggered by volatile anaesthetics and succinylcholine characterized by hypercapnia, hypermetabolism and muscle breakdown. MH is most commonly caused by mutations in the skeletal muscle ryanodine receptor (RYR1) gene, as is rhabdomyolysis triggered by exertion and/or pyrexia. The discrepancy between risk genotypes and actual MH incidence remains unexplained. We hypothesized that MH is a compound event, reflecting a synergistic effect of predisposing genotype, triggering anaesthetic, and exercise and/or pyrexia as modifying factors. Methods: We performed a retrospective study and identified 41 patients with a history of exercise and/or pyrexia within 72 hours prior to an MH event. We compared the frequency of a history of exercise and/or pyrexia within 72 hours of the triggering agent in “eventful anaesthesias” (n=41) and in “uneventful anaesthesias” (n=51) in the index cases and/or their MH susceptible relatives. Indications for and urgency of surgery, and use of succinylcholine were also recorded. Findings: In eventful anaesthesias, there was a history of exercise and/or pyrexia within 72 hours prior to the anaesthetic in 24(0) and 21(1) patients, compared to 0 and 1 in uneventful anesthesias. Trauma and acute abdomen as surgery indications, emergency surgery and succinylcholine use were also more common with eventful anaesthesias. Interpretation: Exercise and/or pyrexia prior to general anaesthesia are risk factors for MH. Rhabdomyolysis may mimic an acute abdomen, whilst trauma surgery may carry a specific risk due to muscle damage. These observations should inform perioperative guidelines with the potential to reduce fatal anaesthesia complications. Funding Statement: This work is not funded. Declaration of Interests: Sheila Riazi, Luuk van den Bersselaar, Gunilla Islander, Luc Heytens, Marc M. J. Snoeck, Andrew Bjorksten, Robyn Gillies, George Dranitsaris, Anna Hellblom, Susan Treves, Nicol C. Voermans, Heinz Jungbluth: These authors declare no financial interests. Ethics Approval Statement: The retrospective case study was performed with Research Ethics Board approval from the University of Toronto (REB Nr 19-5365), and in accordance with the ethics guidelines issued by other participating centres.