Cardiopulmonary bypass in the treatment of malignant hyperthermia

Disorders of Temperature Control: Hyperthermia, Part II

Malignant hyperthermia and neuroleptic malignant syndrome, two hyperthermic syndromes, are discussed with respect to their pathogenesis, pathophysiological factors, diagnosis, differential diagnosis, and treatment. Malignant hyperthermia is a drug- or stress-induced hypermetabolic syndrome characterized by vigorous muscular contractures and cardiovascular collapse. Neuroleptic malignant syndrome results primarily from an imbalance of central neurotransmitters caused by neuroleptic drug use and characterized by mental status changes and muscular rigidity. Recognition and prompt treatment of these disorders reduces their morbidity and mortality.

Malignant hyperthermia in the early days of pediatric anesthesia: an interview with anesthesiology pioneer, Dr. John F. Ryan

Dr. John F. Ryan (1935 - ), Associate Professor of Anaesthesia at the Harvard Medical School, influenced the careers of hundreds of residents and fellows-in-training while instilling in them his core values of resilience, hard work, and integrity. His authoritative textbook, A Practice of Anesthesia for Infants and Children, remains as influential today as it did when first published decades ago. Although he had had many accomplishments, he identified his experiences caring for patients with malignant hyperthermia and characterizing the early discovery of this condition as his defining contribution to medicine. Based on a series of interviews with Dr. Ryan, this article reviews a remarkable career that coincides with the dawn of modern pediatric anesthetic practice.

Non-cardiac surgery applications of extracorporeal circulation

Although the efficacy of extracorporeal circulation (ECC) is well established for open-heart surgery, application of ECC in other surgical areas has not been given much attention. Advances in the related surgical technique and anesthetic management combined with refinements in the ECC procedure itself have encouraged several institutions to use ECC for complex non-cardiac surgeries. ECC is beginning to be used for circulatory support or tissue oxygenation during surgery on the lung, brain, liver, and kidney as well as in emergency situations. With ECC, difficult and complex surgeries can be performed more safely, and the success rate of certain surgeries has been positively affected. It is important that the surgeon, anesthesiologist, and perfusionist are trained in non-cardiac surgery applications of ECC. Thus, we review here non-cardiac uses that have emerged and summarize the related procedures.

Cooling for acute ischemic brain damage (cool aid): an open pilot study of induced hypothermia in acute ischemic stroke

BACKGROUND AND PURPOSE

Hypothermia is effective in improving outcome in experimental models of brain infarction. We studied the feasibility and safety of hypothermia in patients with acute ischemic stroke treated with thrombolysis.

METHODS

An open study design was used. All patients presented with major ischemic stroke (National Institutes of Health Stroke Scale [NIHSS] score >15) within 6 hours of onset. After informed consent, patients with a persistent NIHSS score of >8 were treated with hypothermia to 32+/-1 degrees C for 12 to 72 hours depending on vessel patency. All patients were monitored in the neurocritical care unit for complications. A modified Rankin Scale was measured at 90 days and compared with concurrent controls.

RESULTS

Ten patients with a mean age of 71.1+/-14.3 years and an NIHSS score of 19.8+/-3.3 were treated with hypothermia. Nine patients served as concurrent controls. The mean time from symptom onset to thrombolysis was 3.1+/-1.4 hours and from symptom onset to initiation of hypothermia was 6.2+/-1.3 hours. The mean duration of hypothermia was 47.4+/-20.4 hours. Target temperature was achieved in 3.5+/-1.5 hours. Noncritical complications in hypothermia patients included bradycardia (n=5), ventricular ectopy (n=3), hypotension (n=3), melena (n=2), fever after rewarming (n=3), and infections (n=4). Four patients with chronic atrial fibrillation developed rapid ventricular rate, which was noncritical in 2 and critical in 2 patients. Three patients had myocardial infarctions without sequelae. There were 3 deaths in patients undergoing hypothermia. The mean modified Rankin Scale score at 3 months in hypothermia patients was 3.1+/-2.3.

CONCLUSION

Induced hypothermia appears feasible and safe in patients with acute ischemic stroke even after thrombolysis. Refinements of the cooling process, optimal target temperature, duration of therapy, and, most important, clinical efficacy, require further study.

Malignant hyperthermia

Malignant hyperthermia is a hereditary trait characterized by hypercatabolic reactions induced by anesthetic drugs, or physical or emotional stress. Patients must be treated quickly and efficiently in order to prevent irreversible organ damage and death.

Development of malignant hyperthermia obscured by cardiopulmonary bypass

An episode of malignant hyperthermia occurring in a two-year-old child undergoing cardiac surgery is reported. The coincidental usage of hypothermic cardiopulmonary bypass obscured the classical presenting signs and symptoms of the syndrome. Once the clinical diagnosis was confirmed, rapid reversal was achieved with the administration of dantrolene sodium.

Management of a malignant hyperthermia patient during cardiopulmonary bypass

The anaesthetic management of cardiopulmonary bypass (CPB) for a patient with biopsy-proven malignant hyperthermia is reported. Specific changes in the technique used, such as venting the oxygenator before use, monitoring mixed venous PO2 and PCO2, as well as the safety of cold hyperkalaemic cardioplegia are described. Controversial aspects of malignant hyperthermia management such as the safety of calcium and catechol inotropes are discussed in relationship to the successful use of cardio-pulmonary bypass in our patient. We chose to treat left ventricular dysfunction by aggressive vasodilator (nitroglycerine) therapy. We detected no myocardial or respiratory depression secondary to dantrolene therapy either before or after operation.

Management of malignant hyperthermia

A case of malignant hyperthermia in a young girl with vesicoureteral reflux and multiple congenital abnormalities is discussed. Malignant hyperthermia is a relatively newly defined problem that is associated with anesthesia. It is being recognized with increasing frequency, particularly in children with multiple musculoskeletal anomalies. The term itself is a misnomer. It is a drug-induced syndrome of hypermetabolism that may represent an inborn error of metabolism. Recognition, prophylaxis and crisis management are reviewed, and the use of dantrolene sodium in the care of patients with malignant hyperthermia is discussed. Because recognition of malignant hyperthermia is an important concern for the practicing urologist, the principles of identifying the patient at risk, as well as managing the crisis, should be familiar to the clinician.

Skeletal muscle sarcoplasmic reticulum in porcine malignant hyperthermia

To examine the function of sarcoplasmic reticulum (SR) in malignant hyperthermia, SR was isolated from semitendinosus muscle of normal and genetically susceptible Poland China swine. Determinations included rate of calcium binding (oxalate absent), rate and capacity of calcium uptake (oxalate present), and spontaneous calcium release (in the absence of ionic depolarization or calcium) with and without halothane, using the millipore filtration technique. Rate of calcium binding, and rate and capacity of calcium uptake were decreased, and spontaneous calcium release was greater in SR fragments from susceptible swine as compared to those from normal swine. Halothane 0.5% slightly increased the rate of calcium binding in susceptible and normal SR. Above 1%, halothane decreased calcium binding rate, and uptake rate and capacity, and increased calcium release similarly in susceptible and normal SR. These differences in SR function were insufficient to explain the etiology of malignant hyperthemia, nor did the effect of halothane account for its triggering action.

Malignant hyperthermia. Report of two cases

A dentist using local or general anesthetics must be cognizant of the possibility of malignant hyperthermia presenting as a catastrophic emergency. The purpose of this article is to describe the syndrome of malignant hyperthermia, to emphasize its early clinical symptoms, and to outline definitive treatment. Two cases of malignant hyperthermia in pediatric dental patients illustrate the clinical and laboratory features and the appropriate therapy.

Preoperative and operative considerations in malignant hyperpyrexia

Malignant hyperpyrexia is a condition characterized by fever and often by skeletal muscle rigidity usually triggered by the administration of general anesthetic agents. A review of the current literature is given to emphasize preoperative and operative considerations. An uncomplicated case is presented to illustrate the special care that these individuals require.

Studies of fragmented sarcoplasmic reticulum from human skeletal muscle

Sarcoplasmic reticulum (SR) vesicles were isolated from muscle biopsies of 4 normal volunteers, a patient with McArdle disease (before and during contracture), and a patient with normokalemic periodic paralysis. Fractions were analyzed for purity by electron microscopy and biochemical analysis of specific marker enzymes. Adenosine triphosphate (ATP)-dependent calcium ion uptake was measured kinetically by the absorbence changes of murexide, a metallochromic indicator of ionized Ca++ concentrations, in the absence of oxalate or other calcium-complexing anions. In these experiments, time resolution of the Ca++ transport rate was limited by the manual mixing of reagents, which occurred in 1 to 3 seconds. In 1 case the "true" initial velocity of Ca++ uptake was measured by rapid mixing of ATP in a stopped-flow apparatus and by following the change in absorbence of murexide in a storage oscilloscope. In SR from normal human muscle the ATP-dependent Ca++ uptake was 3.5 nmoles per second per milligram of protein for the first 5 seconds after ATP mixing. Fast kinetic experiments showed that Ca++ uptake proceeded linearly for the first 500 msec at a rate of 9 nmoles per second per milligram of protein (at 25 degrees C) and then progressively declined to reach steady-state levels in 40 to 50 seconds. No abnormality of Ca++ transport was found in SR vesicles from the patient with McArdle disease and the patient with normokalemic periodic paralysis.

Malignant hyperpyrexia during anesthesia in childhood

Malignant hyperpyrexia is a highly lethal complication of general anesthesia. It occurs with sufficient frequency, particularly in children and young adults, to justify use of continuous temperature monitoring during adminnstration of general anesthesia. Fever may be a late manifestation of the malignant hyperpyrexia syndrome, and it is important to be aware of the early signs. Prompt recognition and aggressive management should lower the high mortality known to occur with this complication. Family members should be screened for CPK elevations to determine possible susceptibility to malignant hyperpyrexia. Two case reports illustrate these points of diagnosis and management.