Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024591 (malignant hyperthermia)
 2,353 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isoflurane has a lesser ability than halothane to induce contracture in malignant hyperthermia (MH) muscle in vitro. This does not necessarily imply that isoflurane is not as potent an MH trigger as halothane in vivo. A hypothesis was tested that in vitro treatment with Bay K 8644, an activator of both the dihydropyridine receptors as well as the sodium channels of the T-tubules, potentiates isoflurane-induced MH-susceptible skeletal muscle contracture. In addition to the usual halothane-caffeine test, other muscle bundles were exposed to 10 microM Bay K 8644-halothane and equipotent anesthetic concentrations (expressed in multiple minimum alveolar concentration [MAC]) of isoflurane either alone or combined with Bay K 8644. In 14 MH-susceptible muscle bundles, the mean maximum contracture induced by 2 MAC isoflurane was 0.20 +/- 0.22 g (mean +/- SD), and this value was significantly less than that obtained with 2 MAC halothane (0.68 +/- 0.40 g). Bay K 8644 did not induce muscle contracture on its own but consistently enhanced both the 0.5 MAC isoflurane and halothane to the same maximal isometric tension (1.09 +/- 0.35 g and 1.11 +/- 0.37 g, respectively). Such an effect was not observed in the MH-nonsusceptible group. Under the conditions of this in vitro study, 0.5 MAC isoflurane appears to be as potent as halothane in inducing muscle contracture in skeletal muscle bundles from individuals susceptible to MH.
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PMID:Effect of Bay K 8644 on the magnitude of isoflurane and halothane contracture of skeletal muscle from patients susceptible to malignant hyperthermia. 137 90

The sarcoplasmic reticulum (SR) controls uptake and release of Ca2+ in muscle. Little information is available regarding the effect of volatile anesthetics on Ca2+ release from SR isolated from normal skeletal muscle, even though an abnormality of Ca2+ handling is implicated in malignant hyperthermia. In this study we used a Ca2+ electrode to monitor continuously the release of Ca2+ from SR and the effect of volatile anesthetics on this process. We found that halothane, enflurane, and isoflurane at 0.6, 0.7, and 0.8 vol%, respectively, each increased the velocity of Ca2+ leakage by at least 150% when compared to control. Ruthenium red, a blocker of the SR Ca(2+)-release channel, was shown to have no effect on the velocity of Ca2+ leakage. Halothane and isoflurane both shortened the time at which Ca2+ leakage began (T) in a dose-dependent fashion. Halothane at 4.8 vol% decreased T from 293 +/- 21 s to 149 +/- 20 s. Isoflurane (4.8 vol%) decreased T to 203 +/- 16 s, and enflurane at 5 vol% had little effect, decreasing T to 259 +/- 19 s. We noted a marked stimulation in the ATPase activity of the SR by all three volatile anesthetics. Halothane at 0.63 vol%, isoflurane at 0.42 vol%, and enflurane at 0.62 vol% each increased ATPase activity by at least 300%. We conclude that the stimulation of the velocity of Ca2+ leakage by the volatile anesthetics is related to the more rapid depletion of ATP, but that the shortening of the onset of Ca2+ leakage is a independent phenomenon with a markedly different dose dependence.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Halothane, enflurane, and isoflurane stimulate calcium leakage from rabbit sarcoplasmic reticulum. 153 95

A middle aged man developed very high fever, status epilepticus, and terminal acute renal failure with myoglobinuria after surgery. A post mortem examination showed widespread muscle necrosis with hypercontraction bands. Muscle enzyme studies and electron microscopic examination disclosed central core disease, a condition closely related to malignant hyperpyrexia. This condition is a genetically inherited disorder which can be triggered by certain volatile anaesthetic agents or Suxamethonium. In this patient the condition may have been triggered by either the Isoflurane or the postoperative status epilepticus.
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PMID:Malignant hyperpyrexia: a rare cause of postoperative death. 157 80

Malignant hyperthermia is a potentially lethal syndrome that can be triggered by inhaled anesthetics. Thus, it may be appropriate to utilize equipment that minimizes exposure of susceptible patients to inhaled anesthetics. The rate of release of anesthetic stored in anesthesia delivery systems is unknown. To determine residual anesthetic concentrations, the washout rates of halothane and isoflurane were compared, and the effects of a 1-l/min and a 10-l/min fresh gas flow were evaluated. Halothane concentrations were also measured in samples taken from the fresh gas outlet and the Y-piece of the circle system during four separate studies in which various components of the anesthesia system were replaced. In each study an Ohio Modulus anesthesia machine equipped with an Air-Shields ventilator was exposed to 2% halothane for 18 h. Anesthetic concentrations were determined by a gas chromatograph having a sensitivity of 0.1 ppm. Isoflurane washed out 3-4 times faster than halothane. Residual halothane concentration was approximately equal to tenfold greater when the fresh gas flow was 1 l/min rather than 10 l/min: 194 versus 19 ppm after 1 h of washout. Using a 10-l/min fresh gas flow, halothane concentrations in samples obtained from the Y-piece were similar with original or fresh soda lime but were more than tenfold lower after the fresh gas outlet hose and circle system were replaced (approximately equal to 50 ppm vs. approximately equal to 5 ppm after 5 min of washout).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Preparation of anesthesia machines for patients susceptible to malignant hyperthermia. 316 44

An account is given of unusual course of a hyperthermic crisis in a 23-year-old male who underwent repeated anesthetics. As yet little has been reported about Isoflurane, which we presume to have been the triggering agent. In this case only the surgically untreated lower extremity developed rigor, with which malignant hyperthermia is associated, whereas the surgically treated extremity, where circulation had been stopped with a tourniquet, remained unaffected. Rigor and contracture of the affected extremity were so severe that they led to a compartment syndrome, necessitating fasciotomy. No observation of this kind has been published before. In addition to a discussion of this dissociated effect in malignant hyperthermia, a detailed account of the course of the crisis is given.
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PMID:[Malignant hyperthermia. An unusual course of a rare disease]. 340 97

Anaesthetic machines are prepared for use with patients who are susceptible to malignant hyperpyrexia (MH) by flushing with oxygen at 10 l/min for ten minutes to reduce the anaesthetic concentration to 1 part per million (ppm) or less. Anaesthetic workstations are now often used in place of traditional machines. Workstations have greater internal complexity, and it is not known if they can be made safe for susceptible patients by flushing with oxygen. We used a high sensitivity infrared gas analyser to measure the washout of isoflurane from five Datex-Ohmeda workstations. Measurements were then repeated with a patient breathing circuit. Isoflurane washout occurred in an exponential manner. The time to reach a concentration of 1 ppm at the fresh gas outlet was 17 +/- 7 minutes, and all machines had reached less than 2 ppm by ten minutes. The washout of isoflurane from the machine and patient breathing circuit was much slower than from the machine alone, with a concentration less than 2 ppm reached only after 30 minutes. We conclude that the Datex-Ohmeda workstation can be prepared for use in MH susceptible patients by flushing with oxygen at 10 l/min for ten minutes. Flushing of the patient breathing system is not straightforward, and we recommend using a clean T-piece circuit. If the circle system and ventilator are required for anaesthesia, we suggest using new breathing hoses, rebreathing bag and soda lime cartridge, and ventilating an artificial lung for 30 minutes with a fresh gas flow rate of 10 l/min and tidal volume of 1 litre.
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PMID:Preparing a new generation anaesthetic machine for patients susceptible to malignant hyperthermia. 1263 97

We report on a 25-year old ASA physical status I patient, who developed within 20 minutes a full-blown malignant hyperthermia (MH) in the context of a living donor liver transplantation after 180 minutes of uneventful anaesthesia. The only trigger substance applied was Sevoflurane. The patient had already received a short, uneventful anaesthesia with Isoflurane a couple of years ago. In the context of the special constellation an initial dose of Dantrolene of 10 mg/kg body weight was administered. The patient was stabilised within 30 minutes, and the enzyme levels remained low compared with other case reports. The post-operative in vitro caffeine halothane contracture testing confirmed that son and mother were susceptible to MH, contracture testing in the father was negative. All known triggers may cause life-threatening MH crisis - even after hours and after inconspicuous multiple exposures to known trigger substances. Therefore all trigger substances must be avoided in all patients susceptible to MH.
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PMID:[Delayed onset of malignant hyperthermia crisis during a living donor liver transplantation caused by sevoflurane]. 1504 5