Consensus guidelines on perioperative management of malignant hyperthermia suspected or susceptible patients from the European Malignant Hyperthermia Group

Successful sedation with remimazolam and alfentanil in a child susceptible to malignant hyperthermia: a case report

BACKGROUND

Malignant hyperthermia (MH) is a life-threatening autosomal-dominant disorder caused by mutations in the ryanodine receptor 1 (RYR1) gene, leading to calcium dysregulation in skeletal muscle. Patients with genetically confirmed MH susceptibility must strictly avoid volatile anesthetics and succinylcholine. Intravenous sedation presents a viable alternative, yet evidence supporting remimazolam use in pediatric MH patients remains scarce.

CASE PRESENTATION

We report the first case of a 1-year-old male patient with genetically confirmed MH susceptibility undergoing orchidopexy under remimazolam-alfentanil sedation combined with caudal block. The patient had no MH manifestations intraoperatively or postoperatively and recovered uneventfully.

CONCLUSION

This case demonstrates the feasibility of remimazolam-based sedation in genetically confirmed pediatric MH patients, supporting its safety profile in this population. Further multicenter studies are needed to establish standardized protocols.

Malignant hyperthermia safety - A nationwide survey of publicly funded Swedish healthcare

BACKGROUND

Malignant hyperthermia (MH) is a rare pharmacogenetic disorder that can lead to a life-threatening reaction during general anaesthesia with triggering agents. Prompt life-saving treatment includes the immediate administration of the antidote dantrolene. This study investigated Swedish healthcare providers' awareness and adherence to guidelines and recommendations with respect to MH and whether adherence to safe MH-praxis varies with hospital care-complexity level and private versus public management form.

METHOD

Agreements and procurement specifications between all 21 Swedish County Councils and privately run surgical care providers were reviewed alongside with questionnaire-aided collection of information from 62 publicly funded health care providers (both privately and publicly run).

RESULTS

No procurement requirement specification or contract contained requirements on anaesthesia or aspects of MH. All publicly run hospitals stocked dantrolene and 28 out of 52 (54%) stocked the recommended amount. Seven out of nine (78%) of the privately run institutions stocked dantrolene, and one stocked the recommended amount. Publicly run hospitals adhered to recommendations to a greater extent than privately run institutions, both with respect to stocking of dantrolene (p = .02) and to stocking the recommended amount (p = .03).

CONCLUSIONS

Contracts between Swedish county councils and private surgical care subcontractors rarely outline expectations of standards for the safe practice of anaesthesia such as preparedness to handle a life-threatening MH reaction. Among Swedish publicly funded anaesthesia providers there is room for improvement in adherence to the EMHG guideline on dantrolene availability. Publicly run hospitals seem to have better compliance with these recommendations than privately run institutions. Raising awareness about current guidelines is important to improve safety for known and unknown MH-susceptible individuals.

Thiopentone-based total intravenous anaesthesia for a patient with carnitine palmitoyltransferase II deficiency and malignant hyperthermia susceptibility

In this case report, we discuss the use of a thiopentone infusion for the maintenance of anaesthesia in a patient with confirmed malignant hyperthermia susceptibility and carnitine palmitoyltransferase 2 deficiency. The concurrence of both diagnoses precluded the use of both propofol-based total intravenous anaesthesia and volatile inhalational anaesthesia. This patient had been anaesthetised previously with a triple infusion regimen of thiopentone, midazolam and remifentanil and this was a unique opportunity to compare the two instances. Electroencephalogram-based depth of anaesthesia monitoring was in routine use by the time of the second anaesthetic, and thus, the thiopentone infusion could be adjusted accordingly, resulting in a more rapid emergence time. We hope that this case may serve as an example of suitable anaesthetic alternative should both propofol infusion and inhalational anaesthesia not be an option.

Remimazolam-based total intravenous anesthesia in a patient with a confirmed diagnosis of malignant hyperthermia: a case report

BACKGROUND

Malignant hyperthermia (MH) is a rare, life-threatening disorder of calcium homeostasis in skeletal muscle cells that is triggered by volatile anesthetics and succinylcholine, leading to a hypermetabolic reaction. The pathogenic ryanodine receptor 1 (RYR1) gene variant is critical. Patients susceptible to MH should avoid triggering agents, and total intravenous anesthesia (TIVA) is preferred. Remimazolam is safe in patients with suspected MH.

CASE PRESENTATION

We present the first case of remimazolam treatment in a genetically confirmed patient with MH without MH development. A 72-year-old man with a family history of MH underwent remimazolam-based TIVA. After informed consent was obtained, a muscle biopsy and genetic testing were performed. Intraoperatively and postoperatively, the patient exhibited no signs of MH. An enhanced function of the RYR1 channel into releasing calcium was indicated, and the genetic testing revealed a pathogenic variant of RYR1.

CONCLUSIONS

Remimazolam-based TIVA is safe in patients confirming the diagnosis of MH.

Epidemiological and clinical features of malignant hyperthermia: A scoping review

Malignant hyperthermia (MH) is a potentially fatal inherited pharmacogenetic disorder related to pathogenic variants in the RYR1, CACNA1S, or STAC3 genes. Early recognition of the occurrence of MH and prompt medical treatment are indispensable to ensure a positive outcome. The purpose of this study was to provide valuable information for the early identification of MH by summarizing epidemiological and clinical features of MH. This scoping review followed the methodological framework recommended by Arksey and O'Malley. PubMed, Embase, and Web of science databases were searched for studies that evaluated the epidemical and clinical characteristics of MH. A total of 37 studies were included in this review, of which 26 were related to epidemiology and 24 were associated with clinical characteristics. The morbidity of MH varied from 0.18 per 100 000 to 3.9 per 100 000. The mortality was within the range of 0%-18.2%. Identified risk factors included sex, age, disorders associated with MH, and others. The most frequent initial clinical signs included hyperthermia, sinus tachycardia, and hypercarbia. The occurrence of certain signs, such as hypercapnia, delayed first temperature measurement, and peak temperature were associated with poor outcomes. The epidemiological and clinical features of MH varied considerably and some risk factors and typical clinical signs were identified. The main limitation of this review is that the treatment and management strategies were not assessed sufficiently due to limited information.

Anesthetic Management of a Patient With Central Core Disease Undergoing Thoracoscopic Lung Resection: The Importance of Neuromuscular Monitoring at the Masseter Muscle

Central core disease is a rare muscular disorder in which anesthetic considerations for the prevention of malignant hyperthermia and for avoidance of residual neuromuscular block are required. A 63-year-old woman with central core disease underwent thoracoscopic sublobar lung resection under total IV anesthesia with a prepared anesthetic workstation. The rocuronium-induced neuromuscular block was monitored by using acceleromyography at the left adductor pollicis muscle and the right masseter muscle. The recovery of neuromuscular block at the masseter was slower than that at the adductor pollicis. The patient showed no symptoms of malignant hyperthermia and residual neuromuscular block and had an uneventful postoperative course. In the present case, malignant hyperthermia was successfully prevented with general anesthesia that is free of triggering agents using a prepared anesthetic machine. The authors speculate that the masseter may be an auxiliary site for neuromuscular monitoring to ensure recovery from neuromuscular block in patients with central core disease.

Evaluation of Malignant Hyperthermia Features in Patients with Pathogenic or Likely Pathogenic RYR1 Variants Disclosed through a Population Genomic Screening Program

BACKGROUND

Malignant hyperthermia (MH) susceptibility is a heritable musculoskeletal disorder that can present as a potentially fatal hypermetabolic response to triggering anesthesia agents. Genomic screening for variants in MH-associated genes RYR1 and CACNA1S provides an opportunity to prevent morbidity and mortality. There are limited outcomes data from disclosing variants in RYR1, the most common MH susceptibility gene, in unselected populations. The authors sought to identify the rate of MH features or fulminant episodes after triggering agent exposure in an unselected population undergoing genomic screening including actionable RYR1 variants.

METHODS

The MyCode Community Health Initiative by Geisinger (USA) is an electronic health record-linked biobank that discloses pathogenic and likely pathogenic variants in clinically actionable genes to patient-participants. Available electronic anesthesia and ambulatory records for participants with actionable RYR1 results returned through December 2020 were evaluated for pertinent findings via double-coded chart reviews and reconciliation. Descriptive statistics for observed phenotypes were calculated.

RESULTS

One hundred fifty-two participants had an actionable RYR1 variant disclosed during the study period. None had previous documented genetic testing for MH susceptibility; one had previous contracture testing diagnosing MH susceptibility. Sixty-eight participants (44.7%) had anesthesia records documenting triggering agent exposure during at least one procedure. None received dantrolene treatment or had documented muscle rigidity, myoglobinuria, hyperkalemia, elevated creatine kinase, severe myalgia, or tea-colored urine. Of 120 possibly MH-related findings (postoperative intensive care unit admissions, hyperthermia, arterial blood gas evaluation, hypercapnia, or tachycardia), 112 (93.3%) were deemed unlikely to be MH events; 8 (6.7%) had insufficient records to determine etiology.

CONCLUSIONS

Results demonstrate a low frequency of classic intraanesthetic hypermetabolic phenotypes in an unselected population with actionable RYR1 variants. Further research on the actionability of screening for MH susceptibility in unselected populations, including economic impact, predictors of MH episodes, and expanded clinical phenotypes, is necessary.

EDITOR’S PERSPECTIVE

Effects of Remimazolam on Intracellular Calcium Dynamics in Myotubes Derived from Patients with Malignant Hyperthermia and Functional Analysis of Type 1 Ryanodine Receptor Gene Variants

Remimazolam is a novel general anesthetic and its safety in patients with malignant hyperthermia (MH) is unknown. We used myotubes derived from the skeletal muscle of patients with MH to examine the response to ryanodine receptor 1 (RYR1) agonist and remimazolam in MH-susceptible patients. Patients underwent muscle biopsy for the Ca2+-induced Ca2+ release (CICR) rate test, a diagnostic tool for MH in Japan. Ten patients had myotubes obtained from skeletal muscle cultures, and the genes associated with malignant hyperthermia in these patients were analyzed. The EC50 of caffeine, cresol, and remimazolam to induce intracellular calcium concentration change were compared between myotubes from CICR-negative genetic test patients and myotubes from other patients. Eight of the ten were CICR-positive, five of whom had RYR1 causative gene mutations or variants. Two patients had CICR-negative genetic tests, and as expected had the highest EC50 (the concentration of a drug that gives a half-maximal response) in response to caffeine, 4CmC and remimazolam. Three patients had a positive CICR but no known variants in RYR1 or CACNA1S (voltage-gated calcium channel subunit alpha1S). Myotubes in these patients had significantly lower EC50s for all agents than myotubes in CICR-negative patients. When myotubes from a patient who was CICR-negative and had no gene variant were used as a control, myotubes from CICR-positive patients were more hyper-responsive than controls to all stimulants used. The EC50 for remimazolam was lowest for myotubes from CICR-positive, RYR1-mutant patients, at 206 µM (corresponding to 123 µg/mL). The concentration was more than 80-times higher than the clinical concentration. RYR1 gene variants in R4645Q and W5020G were shown to be causative gene mutations for MH. Intracellular calcium in myotubes from MH patients are elevated at high concentrations of remimazolam but not at clinically used concentrations of remimazolam. Remimazolam appears to be safe to use in patients with MH.

A Single-Center Retrospective Review of Patients with Suspected Malignant Hyperthermia Susceptibility

Purpose The diagnosis of malignant hyperthermia susceptibility (MHS) has significant implications for the perioperative period that may persist for generations. Anesthetic medication options are reduced, anesthetic workstations require preparation to reduce exposure to inhaled volatile anesthetics, and patients may be excluded from surgery at ambulatory centers. In this study, we sought to better characterize the etiology of MHS diagnoses in our health system and the downstream effects of this diagnosis on anesthetic care. Methods We retrospectively reviewed the electronic medical records of 55 patients with a documented concern for MHS who received care at University of Florida (UF) Health between 2014 and 2020. We characterized the etiology of the patient's MHS diagnosis, whether this diagnosis was supported by formal genetic or muscle contracture testing, and the details of the recorded anesthetics that were delivered to these patients. Results The 55 patients with suspected MHS were evenly split between those with a family history of malignant hyperthermia (MH) (28/55) and those with a concern for MHS in their personal medical history (27/55). Of the 28 patients with a family history of MH, 16 reported that the affected family member was a first-degree relative, and two of these 16 reported that the affected family member had undergone confirmatory muscle contracture testing. Of the 27 patients with a personal history suspicious for MHS, two had undergone confirmatory genetic testing, and two patients had anesthetic records available for review where intraoperative MH was suspected and treated with dantrolene. An additional four patients were told of a concern about MHS due to another underlying diagnosis. No patients with a personal history suspicious of MHS had undergone confirmatory muscle contracture testing. These 55 patients underwent 87 anesthetics, and exclusively non-triggering anesthetic techniques were utilized in nearly all cases. In pediatric patients, some perioperative challenges were identified, related to the avoidance of mask inhalational induction. Only six of these 87 anesthetics occurred at our ambulatory surgery centers, a proportion (6.9%) lower than that of the general surgical population at UF Health (20.0%). Conclusions Among patients suspected to be MH susceptible in our health system over a six-year period, a minority (8/55) were supported by clear records of a prior MH event, confirmatory genetic or muscle contracture testing, or an underlying diagnosis closely linked to MH. The vast majority had limited documentation supporting their MH risk but continued to be treated with non-triggering anesthetics and were less likely to have surgery at an ambulatory surgery center than our overall surgical population. Among pediatric patients, some anesthetic challenges related to delivering non-triggering anesthetics were identified. Improving the documentation of index cases of MH and increasing referrals to clinical geneticists and genetic testing may be a viable route to decreasing the proportion of suspected MHS patients with a poorly characterized risk profile.

Current clinical application of dantrolene sodium

Dantrolene sodium (DS) was first introduced as an oral antispasmodic drug. However, in 1975, DS was demonstrated to be effective for managing malignant hyperthermia (MH) and was adopted as the primary therapeutic drug after intravenous administration. However, it is difficult to administer DS intravenously to manage MH. MH is life-threatening, pharmacogenomically related, and induced by depolarizing neuromuscular blocking agents or inhalational anesthetics. All anesthesiologists should know the pharmacology of DS. DS suppresses Ca2+ release from ryanodine receptors (RyRs). RyRs are expressed in various tissues, although their distribution differs among subtypes. The anatomical and physiological functions of RyRs have also been demonstrated as effective therapeutic drugs for cardiac arrhythmias, Alzheimer's disease, and other RyR-related diseases. Recently, a new formulation was introduced that enhanced the hydrophilicity of the lipophilic DS. The authors summarize the pharmacological properties of DS and comment on its indications, contraindications, adverse effects, and interactions with other drugs by reviewing reference articles.

[Trigger-free anesthesia : Indications and safe application]

The safe anesthesiological care of patients with neuromuscular diseases poses a particular challenge for anesthetists. Only a small group of muscle diseases and syndromes are associated with an increased risk of malignant hyperthermia and therefore require trigger-free anesthetic procedures avoiding volatile anesthetics and succinylcholine. These diseases are frequently associated with mutations in the RYR1, CACNA1S or STAC-3 genes. In other neuromuscular diseases, anesthetic-induced rhabdomyolysis can occur. Therefore, volatile anesthetics should be avoided in these patients in addition to the contraindication for succinylcholine. In other neuromuscular diseases the risk of a propofol infusion syndrome or myotonic crises can be elevated or the duration of the effect of non-depolarizing muscle relaxants can be changed in an incalculable way. In every case an individual anesthetic aproach including the avoidance of potential pharmacological or non-pharmacological triggers is essential for the safety of the patients.

Rebounds of sevoflurane concentration during simulated trigger-free pediatric and adult anesthesia

BACKGROUND

In trigger-free anesthesia a volatile anesthetic concentration of 5 parts per million (ppm) should not be exceeded. According to European Malignant Hyperthermia Group (EMHG) guideline, this may be achieved by removing the vapor, changing the anesthetic breathing circuit and renewing the soda lime canister followed by flushing with O2 or air for a workstation specific time. Reduction of the fresh gas flow (FGF) or stand-by modes are known to cause rebound effects. In this study, simulated trigger-free pediatric and adult ventilation was carried out on test lungs including ventilation maneuvers commonly used in clinical practice. The goal of this study was to evaluate whether rebounds of sevoflurane develop during trigger-free anesthesia.

METHODS

A Dräger® Primus® was contaminated with decreasing concentrations of sevoflurane for 120 min. Then, the machine was prepared for trigger-free anesthesia according to EMHG guideline by changing recommended parts and flushing the breathing circuits using 10 or 18 l⋅min- 1 FGF. The machine was neither switched off after preparation nor was FGF reduced. Simulated trigger-free ventilation was performed with volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) including various ventilation maneuvers like pressure support ventilation (PSV), apnea, decreased lung compliance (DLC), recruitment maneuvers, prolonged expiration and manual ventilation (MV). A high-resolution ion mobility spectrometer with gas chromatographic pre-separation was used to measure sevoflurane in the ventilation gas mixture in a 20 s interval.

RESULTS

Immediately after start of simulated anesthesia, there was an initial peak of 11-18 ppm sevoflurane in all experiments. The concentration dropped below 5 ppm after 2-3 min during adult and 4-18 min during pediatric ventilation. Other rebounds of sevoflurane > 5 ppm occurred after apnea, DLC and PSV. MV resulted in a decrease of sevoflurane < 5 ppm within 1 min.

CONCLUSION

This study shows that after guideline-compliant preparation for trigger-free ventilation anesthetic machines may develop rebounds of sevoflurane > 5 ppm during typical maneuvers used in clinical practice. The changes in rate and direction of internal gas flow during different ventilation modes and maneuvers are possible explanations. Therefore, manufacturers should provide machine-specific washout protocols or emphasize the use of active charcoal filters (ACF) for trigger-free anesthesia.

Real Evidence and Misconceptions about Malignant Hyperthermia in Children: A Narrative Review

Malignant hyperthermia is a rare but life-threatening pharmacogenetic disorder triggered by exposure to specific anesthetic agents. Although this occurrence could affect virtually any patient during the perioperative time, the pediatric population is particularly vulnerable, and it has a five-fold higher incidence in children compared to adults. In the last few decades, synergistic efforts among leading anesthesiology, pediatrics, and neurology associations have produced new evidence concerning the diagnostic pathway, avoiding unnecessary testing and limiting false diagnoses. However, a personalized approach and an effective prevention policy focused on clearly recognizing the high-risk population, defining perioperative trigger-free hospitalization, and rapid activation of supportive therapy should be improved. Based on epidemiological data, many national scientific societies have produced consistent guidelines, but many misconceptions are common among physicians and healthcare workers. This review shall consider all these aspects and summarize the most recent updates.

Free-living core body temperature monitoring using a wrist-worn sensor after COVID-19 booster vaccination: a pilot study

Core body temperature (CBT) is a key vital sign and fever is an important indicator of disease. In the past decade, there has been growing interest for vital sign monitoring technology that may be embedded in wearable devices, and the COVID-19 pandemic has highlighted the need for remote patient monitoring systems. While wrist-worn sensors allow continuous assessment of heart rate and oxygen saturation, reliable measurement of CBT at the wrist remains challenging. In this study, CBT was measured continuously in a free-living setting using a novel technology worn at the wrist and compared to reference core body temperature measurements, i.e., CBT values acquired with an ingestible temperature-sensing pill. Fifty individuals who received the COVID-19 booster vaccination were included. The datasets of 33 individuals were used to develop the CBT prediction algorithm, and the algorithm was then validated on the datasets of 17 participants. Mean observation time was 26.4 h and CBT > 38.0 °C occurred in 66% of the participants. CBT predicted by the wrist-worn sensor showed good correlation to the reference CBT (r = 0.72). Bland-Altman statistics showed an average bias of 0.11 °C of CBT predicted by the wrist-worn device compared to reference CBT, and limits of agreement were - 0.67 to + 0.93 °C, which is comparable to the bias and limits of agreement of commonly used tympanic membrane thermometers. The small size of the components needed for this technology would allow its integration into a variety of wearable monitoring systems assessing other vital signs and at the same time allowing maximal freedom of movement to the user.

The Knowledge Profile, Competence and Pending Problems of Chinese Anesthesiologists in Dealing with Malignant Hyperthermia: A Cross-Sectional Survey

Purpose

The National Remote Emergency System for Malignant Hyperthermia (MH-NRES) is an applet in China, designed to help anesthesiologists manage MH crisis. However, there is limited information about encountered difficulties in dealing with MH among Chinese anesthesiologists. The purpose of the study was to explore the current competency and encountered difficulties in the management of MH, as a key first step for assessing the potential user needs to develop the MH-NRES.

Methods

The hospitals of different levels in different provinces across China were invited to participate in an online survey from November to December 2021. Anesthesiologists completed the online questionnaire containing four sections including demographic information, knowledge, competency, and continuing education about MH.

Results

A total of 1357 valid questionnaires were completed from anesthesiologists, most respondents (66.7%, n = 905) correctly answered the MH trigger drugs included volatile anesthetics and succinylcholine. However, most respondents (77.0%, n = 1045) did not know that the recommended initial dose of domestic dantrolene. Up to 83.9% (n = 1138) stated that their hospitals did not store dantrolene for MH emergency. More than half of respondents thought that it would take more than one hour to obtain dantrolene in emergency. Less work experiences, lower levels of hospital and educations and professional titles were associated with lower competency scores in managing MH. Only 31.0% (n = 936) reported that their hospital had ever conducted MH continuing education curricula. Scenario simulation is the training method that most interests the participants (79.0%, n = 1072) but a whopping 46.9% (n = 637) never received simulation.

Conclusion

The study indicated that difficulty in obtaining dantrolene, lack of competency in management of MH, difficulty in obtaining professional help, and poor teamwork were the main problems of most anesthesiologists in face of MH.

Clinical Features of Suspected Malignant Hyperthermia in China from 2015 to 2020: A Retrospective Study from China Malignant Hyperthermia Emergency Assistance Group

Purpose

Malignant hyperthermia (MH) is a rare but fatal pharmacogenetic disorder, triggered by inhalational anesthetics or succinylcholine. Since the first nonprofit academic organization China Malignant Hyperthermia Emergency Assistance WeChat-based Group (CMHEA Group) was established in 2015, they have actively participated in the diagnosis and treatment of MH patients. Based on the CMHEA Group, the aim of the study was to retrospectively analyze the characteristics of suspected MH in China from 2015 to 2020.

Methods

We conducted a retrospective analysis of the suspected MH patients from 2015 to 2020, for analyzing the current clinical diagnosis, treatment and prognosis of MH in China.

Results

A total of 58 suspected MH cases occurred from 2015 to 2020, of these, 36 cases were collected with detailed data. The MH clinical grading score of 36 patients ranged from 33 to 73, with a median of 55. Abnormal hyperthermia and hypercarbia were the most common early signs of MH. Four patients were confirmed carrying six different potential MH-causative mutations. Of the total 58 cases, 14 patients (24.1%) received dantrolene and the whole mortality rate was 53.4%. Compared to the patients not receiving dantrolene treatment, the survival rate of patients receiving dantrolene treatment was significantly higher than that of patients not receiving dantrolene (78.6% vs 36.4%, p = 0.007).

Conclusion

The current main diagnostic methods of suspected MH in China are still clinical diagnosis. Hence, it is critical to keep dantrolene for immediate accessibility with the introduction of domestic dantrolene to China. The WeChat group model has played an important but limited role in quick diagnosis and treatment of MH.

European Neuromuscular Centre consensus statement on anaesthesia in patients with neuromuscular disorders

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 &amp; 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.

Risk of malignant hyperthermia in patients carrying a variant in the skeletal muscle ryanodine receptor 1 gene

Malignant hyperthermia is a life-threatening disorder, which can be prevented by avoiding certain anesthetic agents. Pathogenic variants in the skeletal muscle ryanodine receptor 1-gene are linked to malignant hyperthermia. We retrospectively studied 15 patients who presented to our clinic with symptoms of muscle dysfunction (weakness, myalgia or cramps) and were later found to have a variant in the skeletal muscle ryanodine receptor 1-gene. Symptoms, creatine kinase levels, electromyography, muscle biopsy and in vitro contracture test results were reviewed. Six out of the eleven patients, with a variant of unknown significance in the skeletal muscle ryanodine receptor 1-gene, had a positive in vitro contracture test, indicating malignant hyperthermia susceptibility. In one patient, with two variants of unknown significance, both variants were required to express the malignant hyperthermia-susceptibility trait. Neurologists should consider screening the skeletal muscle ryanodine receptor 1-gene in patients with myalgia or cramps, even when few to no abnormalities on ancillary testing.

Office-based Plastic Surgery-Evidence-based Clinical and Administrative Guidelines

Outpatient procedures are extremely prevalent in plastic surgery, with an estimated 82% of cosmetic plastic surgery occurring in this setting. Given that patient safety is paramount, this practical review summarizes major contemporary, evidence-based recommendations regarding office-based plastic surgery. These recommendations not only outline clinical aspects of patient safety guidelines, but administrative, as well, which in combination will provide the reader/practice with a structure and culture that is conducive to the commitment to patient safety. Proper protocols to address potential issues and emergencies that can arise in office-based surgery, and staff familiarity with thereof, are also necessary to be best prepared for such situations.

Malignant Hyperthermia in PICU—From Diagnosis to Treatment in the Light of Up-to-Date Knowledge

Malignant Hyperthermia (MH) is a rare, hereditary, life-threatening disease triggered by volatile anesthetics and succinylcholine. Rarely, MH can occur after non-pharmacological triggers too. MH was detected more often in children and young adults, which makes this topic very important for every pediatric specialist, both anesthesiologists and intensivists. MH crisis is a life-threatening severe hypermetabolic whole-body reaction. Triggers of MH are used in pediatric intensive care unit (PICU) as well, volatile anesthetics in difficult sedation, status asthmaticus or epilepticus, and succinylcholine still sometimes in airway management. Recrudescence or delayed onset of MH crisis hours after anesthesia was previously described. MH can also be a cause of rhabdomyolysis and hyperpyrexia in the PICU. In addition, patients with neuromuscular diseases are often admitted to PICU and they might be at risk for MH. The most typical symptoms of MH are hypercapnia, tachycardia, hyperthermia, and muscle rigidity. Thinking of the MH as the possible cause of deterioration of a patient’s clinical condition is the key to early diagnosis and treatment. The sooner the correct treatment is commenced, the better patient´s outcome. This narrative review article aims to summarize current knowledge and guidelines about recognition, treatment, and further management of MH in PICU.

Management of patients susceptible to malignant hyperthermia: A surgeon's perspective

OBJECTIVES

Malignant hyperthermia (MH) susceptibility caries broad implications for the care of pediatric surgical patients. While precautions must often be taken for only a vague family history, two options exist to assess MH-susceptibility. We evaluate the use of MH precautions and susceptibility testing at a freestanding children's hospital.

METHODS

This single institution retrospective cohort study identified patients of any age who received general anesthetics utilizing MH precautions over a five-year period. The electronic medical record was further queried for patients diagnosed with MH. The indication for MH precautions and uses of susceptibility testing are assessed. Secondary outcomes included a diagnosis of bona fide MH.

RESULTS

A total of 125 patients received 174 anesthetics with MH precautions at a mean age of 114 months (0-363 months). Otolaryngology was the procedural service most frequently involved in the care of the cohort (n = 45; 26%). A reported personal or family history of MH (n = 102; 59%) was the most common indication for precautions, followed by muscular dystrophy (n = 29; 17%). No MH events occurred in the cohort and further review of ICD-9 and -10 diagnosis codes found no MH diagnoses. No study subjects received muscle biopsy and contracture testing and only 5 (4%) underwent genetic testing for genomic variants known to cause MH susceptibility. A case example is given to highlight the implications of a reported MH history.

CONCLUSION

Otolaryngologists should maintain a familiarity with the precautions necessary to manage patients at risk for MH and MH-like reactions. Without an accessible test to rule out susceptibility, surgeons must rely on a careful history to appropriately utilize precautions. An inappropriate label of "MH-susceptible" may result in decreased access to care and treatment delays.

Referral indications for malignant hyperthermia susceptibility diagnostics in patients without adverse anesthetic events in the era of next-generation sequencing

BACKGROUND

The introduction of next-generation sequencing into the diagnosis of neuromuscular disorders has resulted in an increased number of newly identified RYR1 variants. We hypothesize that there is an increased referral of patients to Malignant Hyperthermia (MH)-units without a personal/family history of adverse anesthetic events suspected for MH. 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 2010-2019 to the MH-units in Antwerp, Lund, Nijmegen and Toronto 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 REVEL 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; personal history of an adverse anesthetic event (211/520; 40.6%), family history of an adverse anesthetic event (115/520; 22.1%), and exertional and/or recurrent rhabdomyolysis (46/520; 8.8%). The proportion of patients referred without a personal/family history of an adverse anesthetic event increased to 43.6% (133/305) between 2015-2019 compared to 28.4% (61/215) in 2010-2014 (P<0.001). Patients with a personal/family history of an adverse anesthetic event were more frequently diagnosed as MH susceptible (133/220; 60.5%) than those without (47/120; 39.2%), (P < 0.001). Due to missing data, 180 medical records were excluded.

CONCLUSION

The proportion of patients referred to MH-units without a personal/family history of an adverse anesthetic event has increased, with 39.2% (47/120) diagnosed as MH susceptible.

Quality of recent clinical practice guidelines in anaesthesia publications using the Appraisal of Guidelines for Research and Evaluation II instrument

Clinical practice guidelines are a valuable resource aiding medical decision-making based on scientific evidence. In anaesthesia, guidelines are increasing in both number and scope, influencing individual practice and shaping local departmental policy. The aim of this review is to assess the quality of clinical practice guidelines published in high impact anaesthesia journals over the past 5 yr using the internationally validated Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. A literature search was conducted in Scopus to identify all guidelines published in the top 10 anaesthesia journals as per Clarivate Analytics Impact Factor from 2016 and 2020. Fifty-one guidelines were included for analysis by five independent appraisers using AGREE II. Each guideline was assessed across six domains and 23 items. Individual domain scores were calculated with a threshold agreed via consensus to represent high-quality guidelines. There was a significant increase in overall score over time (P=0.041), driven by Domain 3 (Rigour of Development, P=0.046). The raw overall score for Domain 3, however, was low. The other domains performed as expected based on previous studies, with Domains 1, 4, and 6 achieving high scores and Domains 2 and 5 incurring poor ratings. Most guidelines studied involved international collaboration but emerged from a single professional society. Use of an appraisal tool was stated as high but poorly detailed. The improvement in the overall score of guidelines and rigour of development is promising; however, only seven guidelines met high-quality criteria, suggesting room for improvement for the overall integrity of guidelines in anaesthesia.

Preparation of Dräger Atlan A350 and General Electric Healthcare Carestation 650 anesthesia workstations for malignant hyperthermia susceptible patients

BACKGROUND

Patients at risk of malignant hyperthermia need trigger-free anesthesia. Therefore, anesthesia machines prepared for safe use in predisposed patients should be free of volatile anesthetics. The washout time depends on the composition of rubber and plastic in the anesthesia machine. Therefore, new anesthesia machines should be evaluated regarding the safe preparation for trigger-free anesthesia. This study investigates wash out procedures of volatile anesthetics for two new anesthetic workstations: Dräger Atlan A350 and General Electric Healthcare (GE) Carestation 650 and compare it with preparation using activated charcoal filters (ACF).

METHODS

A Dräger Atlan and a Carestation 650 were contaminated with 4% sevoflurane for 90 min. The machines were decontaminated with method (M1): using ACF, method 2 (M2): a wash out method that included exchange of internal parts, breathing circuits and soda lime canister followed by ventilating a test lung using a preliminary protocol provided by Dräger or method 3 (M3): a universal wash out instruction of GE, method 4 (M4): M3 plus exchange of breathing system and bellows. Decontamination was followed by a simulated trigger-free ventilation. All experiments were repeated with 8% desflurane contaminated machines. Volatile anesthetics were detected with a closed gas loop high-resolution ion mobility spectrometer with gas chromatographic pre-separation attached to the bacterial filter of the breathing circuits. Primary outcome was time until < 5 ppm of volatile anesthetics and total preparation time.

RESULTS

Time to < 5 ppm for the Atlan was 17 min (desflurane) and 50 min (sevoflurane), wash out continued for a total of 60 min according to protocol resulting in a total preparation time of 96-122 min. The Carestation needed 66 min (desflurane) and 24 min (sevoflurane) which could be abbreviated to 24 min (desflurane) if breathing system and bellows were changed. Total preparation time was 30-73 min. When using active charcoal filters time to < 5 ppm was 0 min for both machines, and total preparation time < 5 min.

CONCLUSION

Both wash out protocols resulted in a significant reduction of trace gas concentrations. However, due to the complexity of the protocols and prolonged total preparation time, feasibility in clinical practice remains questionable. Especially when time is limited preparation of the anesthetic machines using ACF remain superior.

Emergencies in freestanding ambulatory surgery centre

PURPOSE OF REVIEW

Ambulatory surgery is increasing, more procedures as well as more complex procedures are transferred to ambulatory surgery. Patients of all ages including elderly and more fragile are nowadays scheduled for ambulatory surgery. Enhanced recovery after surgery (ERAS) protocols are now developed for further facilitating readily recovery, ambulation, and discharge. Thus, to secure safety, a vigilant planning and preparedness for adverse events and emergencies is mandatory.

RECENT FINDINGS

Proper preoperative assessment, preparation/optimization and collaboration between anaesthetist and surgeon to plan for the optimal perioperative handling has become basic to facilitate well tolerated perioperative course. Standard operating procedures for rare emergencies must be in place. These SOPs should be trained and retrained on a regular basis to secure safety. Check lists and cognitive aids are tools to help improving safety. Audit and analysis of adverse outcomes and deviations is likewise of importance to continuously analyse and implement corrective activity plans whenever needed.

SUMMARY

The present review will provide an oversight of aspects that needs to be acknowledged around planning handling of rare but serious emergencies to secure quality and safety of care in freestanding ambulatory settings.

Malignant hyperthermia in a 16-day-old infant with congenital diaphragmatic hernia: a case report

Malignant hyperthermia (MH) is a severe hypermetabolic disorder associated with dysregulation of calcium homeostasis and is triggered by inhalational anesthetics (isoflurane, sevoflurane, desflurane) and a depolarizing muscle relaxant (succinylcholine). We report the case of a 16-day-old infant undergoing laparoscopic surgery. The patient developed hyperthermia and hypercarbia with muscle rigidity. After the diagnosis of MH, dantrolene was administered with sufficient hydration. The patient was transferred to the pediatric intensive care unit for monitoring and treatment of acute renal injury due to myoglobinuria. Subsequently, two variants of the ryanodine receptor 1 (RYR1) gene were identified in the patient as the mutation point at c.1589G > A p.Arg530His and c.1841G > T p.Arg614Leu, which are known to be associated with MH. This was a rare case of MH in a 16-day-old infant that might be related to two RYR1 mutations inherited from the parents.