Printer Friendly

Malignant Hyperthermia Knowledge.


As a fundamental nursing role, the Nursing Council of New Zealand (NCNZ) requires nurses to understand emergency procedures, plans and lines of communication in a crisis situation. Furthermore, nurses are required to utilise evidence-based knowledge and act appropriately in an emergency to maximise effectiveness of care (NCNZ, 2012).

Malignant hyperthermia (MH) is a crisis situation, a genetic skeletal muscle disorder that is an uncommon but critical medical emergency. It mostly occurs in the perioperative environment due to anaesthetic gases being the cause or trigger. The best way to prevent a MH crisis is to avoid the triggering anaesthetics in susceptible patients. The challenge however, is that nearly all MH events occur in otherwise healthy patients who may have had previous uneventful anaesthetics (Larach, Brandom, Allen, Gronert, & Lehman, 2014). It is important therefore that anaesthetists are aware of MH and take this into consideration every time they anaesthetise a patient (Banek et al., 2013). Nurses also need a comprehensive knowledge and understanding of this critical event as they provide care for patients undergoing procedures requiring anaesthesia.

The following article defines and explores the background, incidence, diagnosis and management of a malignant hyperthermic episode, emphasising the importance of nurses having an understanding of the presentation and treatment of the condition to facilitate early intervention and improve patient outcomes. The topic of MH is especially important in areas which have large MH susceptible populations and Palmerston North in the Manawatu-Horowhenua region of New Zealand is one such area (Pollock, Langton, McDonnell, Tiemessen, & Stowell, 2006). The national database capturing information on MH is held there, but New Zealand is a small country which has a population that is likely to migrate due to work, family and life changes and patients are often transferred to another larger hospital for specialist treatment. It is therefore important for all nurses to have on-going education on MH.

Background and triggering agents

The first reported case of MH was in Australia in 1960. A 21-year-old male had a sudden onset of increased temperature, tachycardia, hypotension and cyanosis shortly after induction of anaesthesia. Following this case, clinicians realised that MH was a hyper-metabolic state occurring within skeletal muscle cells. This is often triggered by administration of common general anaesthetics, including Halothane, Isoflurane, Sevoflurane, Desflurane and Enflurane (Campbell, 2015; Karlett, 1998) plus Succinylcholine (Lee & Wheeler, 1997; Redmond, 2001; Mitchell-Brown, 2012) and a newer medication Penthrox (Methoxyflurane), used to reduce pain (MIMS, 2015).

Malignant hyperthermia is also known to be triggered by emotional stress, heat-stroke, strenuous exercise, exertion, trauma and certain drug-induced myopathies such as "Evans Myopathy" or "King Denborough Syndrome" (Hommertzheim & Steinke, 2006).

In New Zealand, the first reported case of MH was in 1968 when a 20-year-old male died during surgery on his jaw (Mid Central DHB, 2012).

Defining malignant hyperthermia

Many words and phrases are used throughout the literature to describe MH. These include "life threatening situation" (Hirshey-Dirksen, Van Wicklin, Mashman, Neiderer & Merritt, 2013 p330), "inherited hypermetabolic disorder" (Martin, 2009, p20; Pollock et al., 2006), "familial disease or genetic disorder" (Redmond, 2001 p 259).

MH has been further defined as a potentially fatal, rare, life threatening, inherited hyper-metabolic disorder of the skeletal muscle triggered by certain anaesthetic agents (Karlett, 1998; Riazi & Brandom, 2015). In cases of MH, the triggering agent(s) disrupt normal calcium ion concentrations, causing an abnormal increase in calcium uptake by skeletal muscle fibres. Metabolically the trigger allows calcium to flood into the muscle's cells, causing extreme and uncontrolled muscle contractions. This in turn generates significant heat, consumes a large amount of oxygen and causes excess calcium production. The body does not cope and begins to shut down (Hatfield & Tronson, 2009; Martin, 2009; Malignant Hyperthermia Association of the United States, 2015; Banak et al., 2013).


The exact incidence of MH is unknown. There are however, reported occurrences estimated at one in 15,000 anaesthetics in children and one in 20,000 to one in 50,000 anaesthetics in adults (Lee & Wheeler, 1997; Malignant Hyperthermia Association, 2015). There are areas which are classed as high population MH areas due to a large number of families that carry the MH gene. Highly populated areas include Wisconsin, Nebraska, West Virginia and Michigan in the United States. Palmerston North in New Zealand is also classed as a high population MH area with five patients developing MH reactions in Palmerston North Hospital between 1968-2012. Within these susceptible areas, the incidence is notably increased and varies from one in 150 to one in 3000 anaesthetics given (Barnes, Stowell, Bulger, Langton, Pollock, 2015; Rosero, 2009). Incidence therefore varies between high and low concentration areas of MH families in any given geographic area.

National databases are used in many countries to capture information on malignant hyperthermia and are then utilised to inform clinicians. In New Zealand, a database has been maintained since 1991 (Barnes et al., 2015) to capture information about MH, including all known susceptible individuals or potentially susceptible relatives who may have the MH gene. Europe is guided by the European Malignant Hyperthermia Group that also captures incidences and potentially susceptible relatives within the European region. Through these databases and specialty groups' statistics, guidelines and information about MH has been developed.

Presentation and planning

The presentation of MH ranges from immediately the triggering agent is given to up to 36 hours post anaesthetic (Mitchell-Brown, 2012; Stratman, Flynn & Hatton, 2009; Malignant Hyperthermia Association, 2015; Litman & Joshi, 2014). As the triggers are administered in the operating room (OR) environment, it is most likely that MH will occur at the time of the procedure. Research has shown that symptoms can also occur in the post anaesthetic care unit (Mitchell-Brown, 2012, Stratman, Flynn & Hatton, 2009). However, the varying time of onset noted by these authors means the occurrence of MH signs and symptoms could happen anywhere within the perioperative environment, the surgical ward setting or even at home if the patient has had day stay surgery or an outpatient procedure.

Surgeries and procedures requiring anaesthetics or medications which can trigger MH are also often performed in hospitals as day surgery, outpatient cases or dental surgeries. In any of these situations, there may be potential issues. Discharge planning needs to be considered by nurses or medical professionals to ensure patient safety given the possibility of late onset MH (Litman & Joshi, 2014). It is therefore suggested that a strong support network, a responsible and informed escort, transportation and telephone access is available for the patient being discharged home (Redmond, 2001) in case they develop signs or symptoms of MH. Consequently, the responsible adult should know what to watch out for and the action to take if required (Redmond, 2001; Marley & Moline, 2000).

Mortality rate

Without proper recognition and prompt treatment, mortality rates from MH can be as high as 80 per cent (Larach, Gronert, Allen, Brandom, & Lehman, 2010). In contrast, the mortality rate can be reduced to five per cent (Rosenberg, Sambuughin & Dirksen, 2010) with recognition of the problem, quick initiation of treatment and well-trained staff (Sousa & Cunha, 2014). The North American Malignant Hyperthermia Registry database 1987-2006--which included the United States of America and Canada--reported eight cardiac arrests and four deaths in 291 cases of MH (Larach et al., 2010). Of the five Palmerston North patients who developed MH reactions between 1968-2012, two died and three survived (Mid Central DHB, 2014). The national database kept by the anaesthetic department at Mid Central Health is updated regularly.

Clinical presentation

Malignant hyperthermia presents with diverse signs and symptoms, including rigidity of the jaw muscle. This can make it difficult to open the patient's mouth and to intubate if needed. Patients also present with rigidity of other skeletal muscles, increased breathing rate, increased heart rate and an increase in body temperature. This can range from 39[degrees] to 40[degrees] Celsius and reportedly as high as 46[degrees] Celsius (Karlett, 1998; Redmond, 2001). It is noted that symptoms need to be differentiated from hyper-thyroidism, pheochromocytoma and sepsis (Kartlett, 1998; Rosenberg et al., 2010).

For the ward nurse, it may be an increase in temperature in conjunction with an increase in respiratory rate and heart rate which alerts them to a possible problem. In the perioperative setting, one of the first indications is an increase in end tidal carbon dioxide levels (Mitchell-Brown, 2012).


Malignant hyperthermia may often go undetected. A patient may have a mild case or minor symptoms which are not recognised or diagnosed as MH or a patient who is MH susceptible may never be anaesthetised. Furthermore, as many as 50 per cent of patients with MH have had previous anaesthesia without a problem (Rosenberg, 1999; Litwick, 1995).

If there is a strong family history or suspicion of MH, a caffeine-halothane contracture test can be performed to diagnose MH. This test involves a biopsy of skeletal muscle tissue from the person's thigh which is then exposed to caffeine and halothane immediately after extraction. Both caffeine and halothane cause muscle contractions and in the MH susceptible patient that response will be greater than normal (Martin, 2009; Mitchell-Brown, 2009; Haslego, 2002).

Care of the patient with MH

The literature exploring the care of the patient susceptible to MH, or the patient who has an MH crisis, shows recurring themes. These include pre-operative assessment, recognition of MH, the initiation of treatment and length of stays (Barnes et al., 2015; Neacsu, 2006; Martin, 2009; Redmond, 2001). Each of these themes are discussed in further depth below.

Pre-operative assessment

Malignant hyperthermia awareness begins in the pre-operative phase. The Association of Operating Room Nurses (AORN) guidelines remind us that nursing care begins when the patient is scheduled for any procedure involving general anaesthesia (AORN guideline, 2012). The AORN guidelines are used internationally to support recognition, care and treatment of the patient who is MH susceptible or if an MH emergency occurs during the perioperative specialty (Souza, Bispo, Cunha, & Siqueira, 2015; Wong & Denholm, 2011). The pre-operative assessment is a routine check carried out at any stage prior to surgery or diagnostic procedures requiring anaesthesia, ensuring relevant information is collected from the patient and ideally, the family too.

The following two questions pertaining to MH are asked during the pre-operative assessment to determine a patient's susceptibility to the condition: has the patient had an anaesthetic before, if so, what happened? Does the patient know of any blood relative who has experienced a bad anaesthetic reaction? (Neacsu, 2006 p.54). If susceptibility to MH is identified, this information can then be used to alert the team to a potential crisis (Redmond, 2001).

For the patient who is known to be MH susceptible, high levels of anxiety may be expected. DeJohn, (2008) asserts that patients may need on-going reassurance and support through this time, due to their awareness of the risks associated with anaesthesia and MH. This may require further information and explanation to provide reassurance to the patient that a treatment plan has been implemented to ensure safe care by the nursing and medical team.

Recognition of MH and initiation of treatment

To recognise and respond to MH, nurses need to be aware of the signs and symptoms it might cause to initiate early treatment (Mitchell-Brown, 2012). There are multiple actions and interventions required within minutes of the onset of MH (Seifert, Wahr, Pace, Cochrane, Bagnola, 2014). The priority is to stop the triggering agent, maintain anaesthesia with total intravenous anaesthesia (TIVA), administer oxygen, maintain haemodynamic stability and commence cooling and the administration of Dantrolene (Mitchell-Brown, 2012; Martin, 2009).

Dantrolene is a muscle relaxant which works by restoring a normal level of calcium in the muscles and was introduced in 1982 for the treatment of MH (Kolb, Horne, Martz, 1982) The goal of treatment in a MH crisis is to stop the abnormal metabolic process which has occurred due to the increase in calcium. Dantrolene returns the body temperature, haemodynamic and metabolic function to normal (Gurunluoglu et al., 2009). Dantrolene can also be used as a prophylactic medication to prevent or reduce the risk of MH in patients who may be susceptible but have not been tested for the condition (Mitchell-Brown, 2012; Redmond, 2001).

A speedy response and immediate action are critical for survival (DeJohn, 2008; Glahn et al., 2010). Furthermore, DeJohn (2008, p.27) states "there is a strong correlation between the timing of interventions and positive patient outcomes". When symptoms of MH are recognised in a patient, it is vital the nurse initiates treatment for increasing temperature, cardiac changes, difficulty breathing and fluid and electrolyte imbalances.

A Canadian study by Riazi and Brandom, (2014) examined available descriptive and demographic data on patients who had an adverse reaction to anaesthesia and subsequently survived the MH reaction. The study showed 129 adverse anaesthetic events (1992-2011) and examined common characteristics of the anaesthetics administered. The study also demonstrated that a delay in the initiation of treatment and the administration of Dantrolene significantly increased complications associated with MH, such as renal failure (Riazi & Brandom, 2015).

Length of stay

Difference in length of stay within the healthcare setting is also a factor to be taken into consideration if a patient is known to be MH susceptible. In such cases, day stay surgery patients are often admitted post-surgery. A study completed in Palmerston North evaluated the length of stay needed in the perioperative area or PACU for patients with MH (Pollock et al., 2004). The recommendation from this study was that MH susceptible patients should be monitored for a minimum four hours post-operatively in the PACU, before being discharged to the ward setting. However, there is anecdotal evidence to suggest the time-frame a patient remains in PACU may vary according to the anaesthetist's assessment.

Malignant hyperthermia resources

Malignant Hyperthermia Australia and New Zealand (MHANZ, 2012), a group of anaesthetists with a special interest in the treatment and prevention of MH, have developed a resource kit available to support clinical practice in Australia and New Zealand. The resource kit contains information which prioritises the initial management of a MH crisis. This includes task cards to guide clinicians in their roles within a MH emergency, recommendations for contents of a MH box and guidelines for managing the MH susceptible patient. These resources are made available for health professionals to use in conjunction with local hospital guidelines in order to support practice in the clinical environment.


The significance of MH is noted throughout literature. Malignant hyperthermia is recognised as a medical emergency which requires a rapid assessment and early intervention to reduce patient injury and therefore poses a challenge to all Perioperative Nurses. It remains an important risk to be aware of for patients undergoing general anaesthesia (Metterlein et al., 2011). Although that risk may be small, the consequences of MH if not recognised and treated promptly, are great. Knowing about MH and being able to recognise and respond to this emergency situation is a patient safety issue. Nurses play an essential role in the recognition and early activation of processes to manage this life-threatening disorder.


Association of Perioperative Registered Nurses (AORN), (2012). Malignant hyperthermia guideline: Perioperative standards and recommended practices. Denver: AORN.

Banek, R., Weatherwax, J., Spence, D., Perry, S., Muldoon, S., & Capacchione, S. (2013). Delayed onset of suspected malignant hyperthermia during sevoflurane anaesthesia in an Afghan trauma patient: A case report. AANA Journal,81(6), 441-445.

Barnes, C., Stowell, K.M., Bulger, T., Langton, E., & Pollock,N. (2015). Safe duration of postoperative monitoring for malignant hyperthermia patients administered non-triggering anaesthesia: An update. Anaesthesia Intensive Care, 43(1), 98-104.

Campbell, B.D. (2015). Anaesthesia. In Rothrock, J.C. (Eds.), Alexanders Care of the Patient in Surgery. (15th ed) (pp124-154). St Louis, MO: Elsevier Mosby.

DeJohn, P. (2008). Be prepared: Malignant hyperthermia. OR Manager, 24 (6), 26-30. Retrieved from

Glahn, K., Ellis, F., Halsall, P., Muller, C., Snoeck, M., Urwyler, A., & Wappler, F. (2010). Recognising and managing malignant hyperthermia crisis: Guidelines from the European malignant hyperthermia group. British Journal of Anaesthesia, 105 (4), 417-420.

Gurunluoglu, R., Swanson, J.A., Haeck, P.C. (2009). ASPS patient safety committee: Evidence-based patient safety advisory; Malignant hyperthermia. Plastic Reconstructive Surgery, 124 (suppl 4), 68S--81S.

Haslego, S., (2002). Malignant hyperthermia: How to spot it early. Plastic Surgical Nursing 32(2), 80-83.

Hatfield, A., & Tronson, M. (2009). The complete recovery room book (4th ed.). Oxford. New York: Oxford University Press.

Hirshey-Dirksen, S., Van Wicklin, S., Mashman, D., Neiderer, P., & Merritt, D. (2013). Developing effective drills in preparation for a malignant hyperthermia crisis. AORN Journal. 97(3), 329-353. doi: 10.1016/j.aorn.2012.12.009.

Hommertzheim, R. & Steinke, E.E. (2006). Malignant hyperthermia: The perioperative nurses' role. Association of PeriOperative Registered Nurses (AORN) Journal, 83(1), 149-164. doi: 10.1016/S0001-2092(06)60236-6.

Karlett, M., (1998). Malignant hyperthermia: Considerations for ambulatory surgery. Journal of PeriAnaesthesia Nursing, 14(5), 304-312.

Kolb, M.E., Horne M.L., & Martz, R. (1982). Dantrolene in human malignant hyperthermia. Anesthesiology, 56 (4): 254-62. doi:10.1097/00000542-198204000-00005

Larach, M., Brandom, B., Allen, G., Gronert, G. & Lehman, E.B. (2014). Malignant hyperthermia deaths related to inadequate temperature monitoring, 2007-2012: A report from the North American malignant hyperthermia registry of the malignant hyperthermia association of the United States. Anesth Analg, 119(6), 1359-1366.

Larach, M.G., Gronert, G.A., Allen, G.C., Brandon, B.W., & Lehman, E.B. (2010). Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg, 110, 498-507.

Lee, B., & Wheeler, T. (1997). Emergence and recovery from anaesthesia for paediatric patients in the post anaesthesia care unit. Paediatrician annals, 26 (8), 461-469.

Litman,R & Joshi, G. (2014). Malignant hyperthermia in the ambulatory surgery center: How should we prepare? The Journal of the American Society of Anesthesiologists, 6 (120), 1306-1308. Doi:10.1097/ALN.0000000000000256

Litwick, K. (1995). Post Anaesthesia Care Nursing. (2nd ed). St Louis, MO: Mosby. London Deanery accessed 22.03. 2017

Malignant Hyperthermia Australia and New Zealand (MHANZ) (2012). Malignant hyperthermia resource kit. Australian and New Zealand College of Anaesthetists (ANZCA). Retrieved from:

Malignant Hyperthermia Association of the United States. (2015). What is malignant hyperthermia. Retrieved from Display/BrochurePK/8AABF3FB-13B0-BE20FB32516B02D6.cfm.

Marley, R.A., & Moline, B.M. (2000). Patient discharge issues, In Burden, N., Quinn, D.M.D., O'Brien, D et al. (Eds): Ambulatory surgical nursing (2nd ed,), (p 515- 516). Philadelphia, PA: Saunders.

Martin, C. (2009). A practical guide for malignant hyperthermia management. OR Nurse, 5, 20-26. Retrieved from

Mid Central Health District Health Board (Mid Central DHB). (2012). Malignant Hyperthermia background, Retrieved from

Metterlein, T., Zink, W., Kranke, E., Haneya, A., Graf, B., & Kranke, P. (2011). Cardiopulmonary bypass in malignant hyperthermia susceptible patients: A systematic review of published cases. The Journal of Thoracic and Cardiovascular Surgery, 141(6), 1488-1495. Doi: 10.1016/j.jtcvs.2011.01.034.

Mitchell-Brown, F. (2012). Malignant hyperthermia: turn down the heat. Nursing, 2012, 42(5), 39- 44. Doi: 10.1097/01.NURSE.0000414679.93741.6c

Neacsu, A. (2006). Malignant hyperthermia. Nursing Standard, 20 (28), 51-57.

Nursing Council of New Zealand. (2012). Competencies for registered nurses: Te whakarite i nga mahi tapuhi kia tiakina ai te haumaru a- iwi. Regulating nursing practice to protect public safety. Retrieved from

Penthrox (2015). In MIMS annual 2015 (pp. 564). St Leonards, Australia: UBM Medica Australia

Pollock, N., Langton, E., Stowell, K., Simpson, C., & McDonnell, N., (2004). Safe duration of post-operative monitoring for malignant hyperthermia susceptible patients. Anaesthesia Intensive Care, 32, 502-509.

Pollock, N., Langton, E., McDonnell, N., Tiemessen, J., & Stowell, K. (2006). Malignant hyperthermia and daystay surgery. Anaesthesia Intensive Care, 34, 40-45.

Redmond, M. (2001). Malignant Hyperthermia: Perianaesthesia recognition, treatment and care. Journal of Peri Anaesthesia Nursing. 16(4), 259-270.

Riazi, S. & Brandom, B. (2015). Malignant hyperthermia: An update for perioperative nurses. ORNAC Journal, 33(4), 16-20.

Rosenberg, H. (1999). Malignant hyperthermia and related disorders, in Litwack K (ed): Core Curriculum for Perianesthesia Nursing Practice (ed 4). Philadelphia, PA: Saunders, p. 261.

Rosenberg, H., Sambuughin, N., & Dirksen, R. (2010). Malignant hyperthermia susceptibility. In Pagon, R.A., Bird, T.D., Dolan, C.R., Stephans, A., & Adam, M. P. (eds) GeneReviews (database online). Seattle, WA: University of Washington; 1997-2011. Retrieved from

Seifert, P.C., Wahr, J.R., Pace, M., Cochrane, A.B., & Bagnola, A.J. (2014). Crisis management of malignant hyperthermia in the OR. AORN Journal, 100 (2), 189-202.

Sousa, C., & Cunha, A. (2014). Knowledge of nursing professionals of a surgical centre regarding malignant hyperthermia. Revista Gaucha de Enfermagem, 35(3), 43-48.

Sousa, C., Bispo, D., Cunha, A., & Siqueira, I. (2015). Educational Intervention on malignant hyperthermia with nursing professionals of the operating room. The Journal of School Nursing, 49(2), 290-295.

Stratman, R.C., Flynn, J.D., & Hatton, K.W. (2009). Malignant hyperthermia: A pharmocogenic disorder. Orthopaedics, 32(11), 835-838.

Wong, C.A., & Denholm, B. (2011). Malignant hyperthermia: Diagnosis, treatment, and prevention. CME Zone. Retrieved from

By Johanna McCamish

About the author: Johanna McCamish is the current Chair of the Perioperative Nurses College of the New Zealand Nurses Organisation ([PNC.sup.NZNO]). She currently works as a Clinical Nurse Specialist at Counties Manukau supporting the Middlemore and Manukau sites (acutes and elective). She has worked in a variety of surgical settings over the last 25 plus years but has spent the last 20 within the perioperative environment. Johanna has completed her master's in nursing, with a research topic of malignant hyperthermia and nurses' knowledge. She has an interest in the education and support of staff within the perioperative environment.
COPYRIGHT 2019 New Zealand Nurses' Organisation, Perioperative Nurses College
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2019 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:clinical
Author:McCamish, Johanna
Publication:The Dissector: Journal of the Perioperative Nurses College of the New Zealand Nurses Organisation
Date:Mar 1, 2019
Previous Article:Endovascular Embolisation.
Next Article:The role of organisational commitment in facilitating assimilation of undergraduate nurses into the perioperative environment.

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |