Health worker exposure risk during inhalation sedation with sevoflurane using the (AnaConDa®) anaesthetic conserving device

Prospective Observational Study of Volatile Sedation with Sevoflurane After Aneurysmal Subarachnoid Hemorrhage Using the Sedaconda Anesthetic Conserving Device

BACKGROUND

Volatile sedation is still used with caution in patients with acute brain injury because of safety concerns. We analyzed the effects of sevoflurane sedation on systemic and cerebral parameters measured by multimodal neuromonitoring in patients after aneurysmal subarachnoid hemorrhage (aSAH) with normal baseline intracranial pressure (ICP).

METHODS

In this prospective observational study, we analyzed a 12-h period before and after the switch from intravenous to volatile sedation with sevoflurane using the Sedaconda Anesthetic Conserving Device with a target Richmond Agitation Sedation Scale score of - 5 to - 4. ICP, cerebral perfusion pressure (CPP), brain tissue oxygenation (PBrO2), metabolic values of cerebral microdialysis, systemic cardiopulmonary parameters, and the administered drugs before and after the sedation switch were analyzed.

RESULTS

We included 19 patients with a median age of 61 years (range 46-78 years), 74% of whom presented with World Federation of Neurosurgical Societies grade 4 or 5 aSAH. We observed no significant changes in the mean ICP (9.3 ± 4.2 vs. 9.7 ± 4.2 mm Hg), PBrO2 (31.0 ± 13.2 vs. 32.2 ± 12.4 mm Hg), cerebral lactate (5.0 ± 2.2 vs. 5.0 ± 1.9 mmol/L), pyruvate (136.6 ± 55.9 vs. 134.1 ± 53.6 µmol/L), and lactate/pyruvate ratio (37.4 ± 8.7 vs. 39.8 ± 9.2) after the sedation switch to sevoflurane. We found a significant decrease in mean arterial pressure (MAP) (88.6 ± 7.6 vs. 86.3 ± 5.8 mm Hg) and CPP (78.8 ± 8.5 vs. 76.6 ± 6.6 mm Hg) after the initiation of sevoflurane, but the decrease was still within the physiological range requiring no additional hemodynamic support.

CONCLUSIONS

Sevoflurane appears to be a feasible alternative to intravenous sedation in patients with aSAH without intracranial hypertension, as our study did not show negative effects on ICP, cerebral oxygenation, or brain metabolism. Nevertheless, the risk of a decrease of MAP leading to a consecutive CPP decrease should be considered.

Practical approach to inhaled sedation in the critically ill patient. Sedation, analgesia and Delirium Working Group (GTSAD) of the Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC)

The use of sedatives in Intensive Care Units (ICU) is essential for relieving anxiety and stress in mechanically ventilated patients, and it is related to clinical outcomes, duration of mechanical ventilation, and length of stay in the ICU. Inhaled sedatives offer benefits such as faster awakening and extubation, decreased total opioid and neuromuscular blocking agents (NMB) doses, as well as bronchodilator, anticonvulsant, and cardiopulmonary and neurological protective effects. Inhaled sedation is administered using a specific vaporizer. Isoflurane is the recommended agent due to its efficacy and safety profile. Inhaled sedation is recommended for moderate and deep sedation, prolonged sedation, difficult sedation, patients with acute respiratory distress syndrome (ARDS), status asthmaticus, and super-refractory status epilepticus. By offering these significant advantages, the use of inhaled sedatives allows for a personalized and controlled approach to optimize sedation in the ICU.

Guidelines for inhaled sedation in the ICU

INTRODUCTION AND OBJECTIVES

Sedation is used in intensive care units (ICU) to improve comfort and tolerance during mechanical ventilation, invasive interventions, and nursing care. In recent years, the use of inhalation anaesthetics for this purpose has increased. Our objective was to obtain and summarise the best evidence on inhaled sedation in adult patients in the ICU, and use this to help physicians choose the most appropriate approach in terms of the impact of sedation on clinical outcomes and the risk-benefit of the chosen strategy.

METHODOLOGY

Given the overall lack of literature and scientific evidence on various aspects of inhaled sedation in the ICU, we decided to use a Delphi method to achieve consensus among a group of 17 expert panellists. The processes was conducted over a 12-month period between 2022 and 2023, and followed the recommendations of the CREDES guidelines.

RESULTS

The results of the Delphi survey form the basis of these 39 recommendations - 23 with a strong consensus and 15 with a weak consensus.

CONCLUSION

The use of inhaled sedation in the ICU is a reliable and appropriate option in a wide variety of clinical scenarios. However, there are numerous aspects of the technique that require further study.

[Zero Emissions. A shared responsibility. Gas capture and recycling project at the Cruces University Hospital (Spain).]

OBJECTIVE

The use of volatile anesthetics plays an important role in the production of greenhouse gases and other environmental pollutants that negatively affect global health. Programs to reduce anesthesia contaminants have been shown to be effective and reduce costs. For this reason, we conducted a study to implementing a Zero Emissions Program for zero carbon dioxide emissions derived from anesthetic gases used in the operating room, as recommended by the Green Deal of the European Union by 2030 and be climate neutral in 2050, maintaining satisfaction and current clinical results.

METHODS

A Zero Emissions Program was implemented within the Zero safety programs of the Cruces University Hospital in order to produce zero emissions of carbon dioxide derived from the anesthetic gases used in the operating rooms. The contribution of anesthetic gases to carbon dioxide production before and after implementation of program was determined. Data analysis was conducted descriptively to analyze program effectiveness.

RESULTS

The implementation of a Zero Emissions Program allowed us to achieve a reduction in emissions to zero.

CONCLUSIONS

Anesthesiologists must understand that minimizing our harmful impact on environmental health sustainability is not only desirable, but ethically necessary. A way to contribute to this ethical responsibility is Zero Emissions Programs which are effective in reducing emissions to zero, probably improving our impact on planet health.

Co-exposures to physical and psychosocial work factors increase the occurrence of workplace injuries among French care workers

Objective

The aim of this study was to analyze the effect of co-exposures to physical and psychosocial factors (PSF) regarding the incidence of workplace injuries (WI) among care workers. Additional objective was to identify the work factors associated with the co-exposure combinations leading to the highest rates of WI.

Methods

The study sample consisted of 4,418 care workers participating to the French Working Conditions Survey both in 2013 and 2016. WI were assessed during the 4-year follow-up by matching the databases of the National Health Insurance Funds' compensation system. We assessed exposure for physical factors and PSF using factorial analyses and hierarchical clustering. We implemented a Poisson regression model with the WI incidence as the outcome and the clusters as independent variables of interest. Logistic regression model allowed identifying the work factors that predicted co-exposure combinations with a WI rate > 40%.

Results

WI were highly related to both physical and psychosocial exposures. With low exposure to one or the other, there was no increased risk of WI. Physical factors and PSF potentiated each other and their co-exposure significantly increased the risk of WI, with model predicted rates per 1,000 persons-year for those most exposed to physical risk of 14.6 [4.5-24.8] with low PSF and 38.0 [29.8-46.3] with high PSF. Work factors that predicted co-exposure combinations with a rate > 40 WI% were: working as nursing assistant or hospital services officer, lack of predictability and flexibility of schedules, overtime, controlled schedules, work-family imbalance and insufficient preventive measures.

Conclusions

Our findings highlight the need to take into account psychosocial factors in addition of only considering physical factors when analyzing WI occurrence, as usually done. Prevention actions must be taken to reduce both physical and psychosocial exposure. These results provide keys points for the prevention of WI among care workers.

[Environmentally friendly absorption of anesthetic gases : First experiences with a commercial anesthetic gas capture system]

Anesthetic gases are potent greenhouse gases, which are currently released into the atmosphere where they remain for many years. Strategies to reduce the carbon footprint in anesthesiology without compromising patient safety are urgently needed. Since 2020 several departments of anesthesiology have installed anesthetic gas capture systems with which anesthetic gases can be collected. This article aims to describe the anesthetic gas capture system CONTRAfluran™ and to give an overview of the first experiences in four departments of anesthesiology working with the new device in the daily clinical routine. The CONTRAfluran™ system presents a new concept in the surgical setting that has the potential to reduce the carbon footprint in anesthesiology; however, in order to accurately estimate CO₂ equivalent savings, more information concerning the reprocessing and data on the pharmacokinetics of anesthetic gases are needed. Application of the CONTRAfluran™ system in daily clinical routine is feasible when anesthesiologists are aware of specific issues. In order to minimize the carbon footprint, it remains essential to implement the specific recommendations in the position paper of the German Society of Anaesthesiology and Intensive Care medicine (DGAI) and the Professional Association of German Anaesthesiologists (BDA) on ecological sustainability in anesthesiology and intensive care medicine and to support further research.

Safety and Feasibility of AnaConDa™ to Deliver Inhaled Isoflurane for Sedation in Patients Undergoing Elective Postoperative Mechanical Ventilation: A Prospective, Open-label, Interventional Trial (INSTINCT I Study)

Aim

Sedation is essential during invasive mechanical ventilation, and conventionally intravenous analgesic and sedative drugs are used. Sedation with inhaled anesthetics using anesthesia conserving device (ACD) is an alternative. There is no data on the safety and ease of use of AnaConDa™ from India.

Materials and methods

After IEC approval and informed consent, we used AnaConDa™-S for Isoflurane sedation in 50 hemodynamically stable (need for <0.5 µg/kg/min of Noradrenaline infusion), ASA I and II patients aged 18-80 years, undergoing elective mechanical ventilation for up to 24 hours after elective oncosurgeries. Patients with mental obtundation (GCS <14), or if pregnant, were excluded. The primary outcome was time spent between RASS scores of -3 and -4, while secondary outcomes were incidence of delirium, technical problems with AnaConDa™, and adverse systemic effects of isoflurane. Bolus doses of isoflurane 0.2-0.5 mL were given if the Richmond agitation sedation scale (RASS) score was not achieved.

Results

Fifty patients received isoflurane infusion for a median of 720 (IQR 630-900) minutes, and all remained in the target sedation range. Median time to awakening [19 (IQR, 5-85) minutes], to follow simple verbal commands [20 (IQR 5-180) minutes], and extubation after stopping the infusion of isoflurane was quick [100 (10-470) minutes]. All patients remained hemodynamically stable. None of the patients had delirium.

Conclusion

Target sedation levels were achieved with initial boluses of isoflurane using AnaConDa™-S. Isoflurane sedation delivery using AnaConDa™-S is safe and feasible.

How to cite this article

Kulkarni AP, Bhosale SJ, Kalvit KR, Sahu TK, Mohanty R, Dhas MM, et al. Safety and Feasibility of AnaConDa™ to Deliver Inhaled Isoflurane for Sedation in Patients Undergoing Elective Postoperative Mechanical Ventilation: A Prospective, Open-label, Interventional Trial (INSTINCT I Study). Indian J Crit Care Med 2022;26(8):906-912.

Inhaled Sedation for Invasively Ventilated COVID-19 Patients: A Systematic Review

Background: Volatile anesthetics were used as sedative agents in COVID-19 (Coronavirus Disease 2019) invasively ventilated patients for their potentially beneficial pharmacological effects and due to the temporary shortages of intravenous agents during the pandemic crisis. Methods: Online databases (PubMed, EMBASE, The Cochrane Central Register of Controlled Trial) and the “clinicaltrials.gov” website were searched for studies reporting the use of isoflurane, sevoflurane or desflurane. Results: We identified three manuscripts describing the beneficial effects of isoflurane on 41 COVID-19 patients with acute respiratory distress syndrome (ARDS) in Germany (n = 2) and in the USA (n = 1), in terms of reduction in the use of opioids and other sedatives. We also found a case report of two patients with transient nephrogenic diabetes insipidus, which started after 6 and 8 days of sevoflurane sedation. We identified two randomized controlled trials (RCTs; 92 patients overall), two observational studies (238 patients) on the use of volatile anesthetics in COVID-19 patients that were completed but not yet published, and one RCT interrupted for a low recruitment ratio (19 patients) and thus not published. We also identified five ongoing RCTs on the use of inhaled sedation in ARDS, which are also likely to be recruiting COVID-19 patients and which have currently enrolled a total of >1643 patients. Conclusion: Isoflurane was the most frequently used volatile agent in COVID-19 patients and allowed a reduction in the use of other sedative and analgesic drugs. Randomized evidence is building up and will be useful to confirm or challenge these findings.

Extracorporeal membrane oxygenation and inhaled sedation in coronavirus disease 2019-related acute respiratory distress syndrome

Coronavirus disease 2019 (COVID-19) related acute respiratory distress syndrome (ARDS) is a severe complication of infection with severe acute respiratory syndrome coronavirus 2, and the primary cause of death in the current pandemic. Critically ill patients often undergo extracorporeal membrane oxygenation (ECMO) therapy as the last resort over an extended period. ECMO therapy requires sedation of the patient, which is usually achieved by intravenous administration of sedatives. The shortage of intravenous sedative drugs due to the ongoing pandemic, and attempts to improve treatment outcome for COVID-19 patients, drove the application of inhaled sedation as a promising alternative for sedation during ECMO therapy. Administration of volatile anesthetics requires an appropriate delivery. Commercially available ones are the anesthetic gas reflection systems AnaConDa^® and MIRUS^TM, and each should be combined with a gas scavenging system. In this review, we describe respiratory management in COVID-19 patients and the procedures for inhaled sedation during ECMO therapy of COVID-19 related ARDS. We focus particularly on the technical details of administration of volatile anesthetics. Furthermore, we describe the advantages of inhaled sedation and volatile anesthetics, and we discuss the limitations as well as the requirements for safe application in the clinical setting.

Environmental and Occupational Considerations of Anesthesia: A Narrative Review and Update

With an estimated worldwide volume of 266 million surgeries in 2015, the call for general inhalation anesthesia is considerable. However, widely used volatile anesthetics such as N2O and the highly fluorinated gases sevoflurane, desflurane, and isoflurane are greenhouse gases, ozone-depleting agents, or both. Because these agents undergo minimal metabolism in the body during clinical use and are primarily (≥95%) eliminated unchanged via exhalation, waste anesthetic gases (WAGs) in operating rooms and postanesthesia care units can pose a challenge for overall elimination and occupational exposure. The chemical properties and global warming impacts of these gases vary, with atmospheric lifetimes of 1-5 years for sevoflurane, 3-6 years for isoflurane, 9-21 years for desflurane, and 114 years for N2O. Additionally, the use of N2O as a carrier gas for the inhalation anesthetics and as a supplement to intravenous (IV) anesthetics further contributes to these impacts. At the same time, unscavenged WAGs can result in chronic occupational exposure of health care workers to potential associated adverse health effects. Few adverse effects associated with WAGs have been documented, however, when workplace exposure limits are implemented. Specific measures that can help reduce occupational exposure and the environmental impact of inhaled anesthetics include efficient ventilation and scavenging systems, regular monitoring of airborne concentrations of waste gases to remain below recommended limits, ensuring that anesthesia equipment is well maintained, avoiding desflurane and N2O if possible, and minimizing fresh gas flow rates (eg, use of low-flow anesthesia). One alternative to volatile anesthetics may be total intravenous anesthesia (TIVA). While TIVA is not associated with the risks of occupational exposure or atmospheric pollution that are inherent to volatile anesthetic gases, clinical considerations should be weighed in the choice of agent. Appropriate procedures for the disposal of IV anesthetics must be followed to minimize any potential for negative environmental effects. Overall, although their contributions are relatively low compared with those of other human-produced substances, inhaled anesthetics are intrinsically potent greenhouse gases and pose a risk to operating-room personnel if not properly managed and scavenged. Factors to reduce waste and minimize the future impact of these substances should be considered.

Environmental safety: Air pollution while using MIRUS™ for short-term sedation in the ICU

BACKGROUND

MIRUS™ is a device for target-controlled inhalational sedation in the ICU in combination with use of isoflurane, or sevoflurane, or desflurane. The feasibility of this device has recently been proven; however, ICU staff exposure may restrict its application. We investigated ICU ambient room pollution during daily work to estimate ICU personnel exposure while using MIRUS™.

METHODS

This observational study assessed pollution levels around 15 adult surgical patients who received volatile anaesthetics-based sedation for a median of 11 hours. Measurements were performed by photoacoustic gas monitoring in real-time at different positions near the patient and in the personnel's breathing zone. Additionally, the impact of the Clean Air™ open reservoir scavenging system on volatile agent pollution was evaluated.

RESULTS

Baseline concentrations [ppm] during intervention and rest periods were isoflurane c ¯ mean = 0.58 ± 0.49, c ¯ max = 5.72; sevoflurane c ¯ mean = 0.22 ± 0.20, c ¯ max = 7.93; and desflurane c ¯ mean = 0.65 ± 0.57, c ¯ max = 6.65. Refilling MIRUS™ with liquid anaesthetic yielded gas concentrations of c ¯ mean = 2.18 ± 1.48 ppm and c ¯ max = 13.03 ± 9.37 ppm in the personnel's breathing zone. Air pollution in the patient's room was approximately five times higher without a scavenging system.

CONCLUSION

Ambient room pollution was minimal in most cases, and the measured values were within or below the recommended exposure limits. Caution should be taken during refilling of the MIRUS™ system, as this was accompanied by higher pollution levels. The combined use of air-conditioning and gas scavenging systems is strongly recommended.

An Exploratory Study of Sevoflurane as an Alternative for Difficult Sedation in Critically Ill Children

OBJECTIVES

To analyze the effectiveness of inhaled sevoflurane in critically ill children with challenging sedation.

DESIGN

Prospective case series.

SETTING

Two PICUs of university hospitals in Spain.

INTERVENTIONS

Prospective observational study and exploratory investigation conducted in two PICUs in Madrid, Spain, over a 6-year period. Children treated with inhaled sevoflurane due to difficult sedation were included. Sevoflurane was administered via the anesthetic conserving device (AnaConDa) connected to a Servo-I ventilator (Maquet, Solna, Sweden). A morphine infusion was added to sevoflurane for analgesia. Demographic and clinical data, oral and IV sedatives, Sedation and Analgesic Clinical scores, and Bispectral Index Score monitoring were registered.

MEASUREMENTS AND MAIN RESULTS

Twenty-three patients with a median age of 6 months old were included. Fifty percentage of the patients had critical heart diseases. Sedative and analgesic drugs used before starting sevoflurane were mainly midazolam (63%) and fentanyl (53%). Six patients (32%) also received muscle relaxants. Sevoflurane was administered for a median of 5 days (interquartile range, 5.5-8.5 d). Median end-tidal sevoflurane concentration was 0.8% (interquartile range, 0.7-0.85%), achieved with an infusion rate of 7.5 mL/hr (5.7-8.6 mL/hr). After 48 hours of treatment, some sedative drugs could be removed in 18 patients (78%). Median Bispectral Index Score value prior to sevoflurane administration was 61 (interquartile range, 49-62), falling to 42 (interquartile range, 41-47; p < 0.05) after 6 hours of treatment. Six patients (26%) presented withdrawal syndrome after sevoflurane suspension, and all of them had received sevoflurane at least for 6 days. The main side effect was moderate hypotension in seven patients (30%).

CONCLUSIONS

Inhaled sevoflurane appeared to be an effective sedative agent in critically ill children and can be useful in those patients on mechanical ventilation difficult to sedate with conventional drugs. It can be administered easily in the PICU with conventional ventilators using the AnaConDa system. Withdrawal syndrome may occur with prolonged treatment.

A technical review of the history, development and performance of the anaesthetic conserving device "AnaConDa" for delivering volatile anaesthetic in intensive and post-operative critical care

There is a shift in critical care to adopt volatile anaesthetics as sedatives for certain patients using mechanical ventilation. Accompanying this shift is a growing body of literature describing the advantages or disadvantages of using isoflurane or sevoflurane for long term sedation. This practise requires a cost effective, efficient and safe means to deliver these drugs that can simultaneously operate with modern critical care ventilators and ventilation protocols while protecting the care environment and care workers from excessive exposure to the drugs. The anaesthetic conserving device (“AnaConDa”, Sedana Medical) is one device that delivers a safe sedative dose of either isoflurane or sevoflurane to a patient using existing critical care ventilators, common syringe pumps and gas monitors. The device is essentially a small disposable anaesthetic vaporizer and HME filter combined into one airway component. Similar to an HME filter, the device reflects moisture back to the patient, but also reflects 90% of the anaesthetic by adsorbing and releasing the drug using a proprietary carbon filament reflecting medium. This reflection reduces the total amount of anaesthetic needed, reducing that which is exhausted or scavenged upon exhalation. It can be used for 24 h of sedation, and fits into current critical care ventilator circuits almost without modifications. This article will describe the physical characteristics of the device, how it works, its development history and the performance parameters under which it can be used.

Inhaled anesthetic agent sedation in the ICU and trace gas concentrations: a review

There is a growing interest in the use of volatile anesthetics for inhalational sedation of adult critically ill patients in the ICU. Its safety and efficacy has been demonstrated in various studies and technical equipment such as the anaesthetic conserving device (AnaConDa™; Sedana Medical, Uppsala, Sweden) or the MIRUS™ system (Pall Medical, Dreieich, Germany) have significantly simplified the application of volatile anesthetics in the ICU. However, the personnel's exposure to waste anesthetic gas during daily work is possibly disadvantageous, because there is still uncertainty about potential health risks. The fact that average threshold limit concentrations for isoflurane, sevoflurane and desflurane either differ significantly between countries or are not even defined at all, leads to raising concerns among ICU staff. In this review, benefits, risks, and technical aspects of inhalational sedation in the ICU are discussed. Further, the potential health effects of occupational long-term low-concentration agent exposure, the staffs' exposure levels in clinical practice, and strategies to minimize the individual gas exposure are reviewed.

Volatile Agents in Medical and Surgical Intensive Care Units: A Meta-Analysis of Randomized Clinical Trials

OBJECTIVE

To comprehensively assess published randomized peer-reviewed studies related to volatile agents used for sedation in intensive care unit (ICU) settings, with the hypothesis that volatile agents could reduce time to extubation in adult patients.

DESIGN

Systematic review and meta-analysis of randomized trials.

SETTING

Intensive care units.

PARTICIPANTS

Critically ill patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The BioMedCentral, PubMed, Embase, and Cochrane Central Register databases of clinical trials were searched systematically for studies on volatile agents used in the ICU setting. Articles were assessed by trained investigators, and divergences were resolved by consensus. Inclusion criteria included random allocation to treatment (volatile agents versus any intravenous comparator, with no restriction on dose or time of administration) in patients requiring mechanical ventilation in the ICU. Twelve studies with 934 patients were included in the meta-analysis. The use of halogenated agents reduced the time to extubation (standardized mean difference = -0.78 [-1.01 to -0.55] hours; p for effect<0.00001; p for heterogeneity = 0.18; I(2) = 32% in 7 studies with 503 patients). Results for time to extubation were confirmed in all subanalyses (eg, medical and surgical patients) and sensitivity analyses. No differences in length of hospital stay, ICU stay, and mortality were recorded.

CONCLUSIONS

In this meta-analysis of randomized trials, volatile anesthetics reduced time to extubation in medical and surgical ICU patients. The results of this study should be confirmed by large and high-quality randomized controlled studies.

Malignant hyperthermia: a review

Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases such as halothane, sevoflurane, desflurane, isoflurane and the depolarizing muscle relaxant succinylcholine, and rarely, in humans, to stressors such as vigorous exercise and heat. The incidence of MH reactions ranges from 1:10,000 to 1: 250,000 anesthetics. However, the prevalence of the genetic abnormalities may be as great as one in 400 individuals. MH affects humans, certain pig breeds, dogs and horses. The classic signs of MH include hyperthermia, tachycardia, tachypnea, increased carbon dioxide production, increased oxygen consumption, acidosis, hyperkalaemia, muscle rigidity, and rhabdomyolysis, all related to a hypermetabolic response. The syndrome is likely to be fatal if untreated. An increase in end-tidal carbon dioxide despite increased minute ventilation provides an early diagnostic clue. In humans the syndrome is inherited in an autosomal dominant pattern, while in pigs it is autosomal recessive. Uncontrolled rise of myoplasmic calcium, which activates biochemical processes related to muscle activation leads to the pathophysiologic changes. In most cases, the syndrome is caused by a defect in the ryanodine receptor. Over 400 variants have been identified in the RYR1 gene located on chromosome 19q13.1, and at least 34 are causal for MH. Less than 1 % of variants have been found in CACNA1S but not all of these are causal. Diagnostic testing involves the in vitro contracture response of biopsied muscle to halothane, caffeine, and in some centres ryanodine and 4-chloro-m-cresol. Elucidation of the genetic changes has led to the introduction of DNA testing for susceptibility to MH. Dantrolene sodium is a specific antagonist and should be available wherever general anesthesia is administered. Increased understanding of the clinical manifestation and pathophysiology of the syndrome, has lead to the mortality decreasing from 80 % thirty years ago to <5 % in 2006.