1Department of Applied Physiology, 2Department of Anaesthesiology, University of Ulm, Ulm, Germany
Presented in part at the 10th European Congress of Anaesthesiology, Frankfurt/Main, Germany, June 30July 4, 1998.
Accepted for publication: June 20, 2000
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Br J Anaesth 2000; 85: 71216
Keywords: anaesthetics inhalational, xenon; complications, malignant hyperthermia
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The main causative gene (RYR1) encodes the high molecular weight ligand-gated calcium channel, the ryanodine receptor type 16 7 located in the sarcoplasmic reticulum (SR). Over 20 mutations have been reported in the RYR1 gene on chromosome 19q12-13.2, accounting for approximately 20% of all cases. By linkage, more than 50% of families are linked to RYR18 9 indicating that many mutations are unidentified. Two mutations in the gene on chromosome 1q encoding the 1-subunit of the skeletal muscle dihydropyridine receptor (DHPR) have also been described, each in a single pedigree (for review see10). In the muscle, volatile anaesthetics cause an increase in myoplasmic calcium concentration11 leading to muscle contracture and hypermetabolism. These effects are utilized in the in-vitro contracture test (IVCT)12, the diagnostic gold standard.13
Since 1939 the inert gases have been known to exert anaesthetic properties at hyperbaric pressure.14 In addition, xenon produces anaesthesia at atmospheric pressure.15 Xenon was first used for anaesthesia in man in 1951.16 It causes no significant increases in plasma catecholamine concentrations or adverse effects on myocardial function.17 With a minimum alveolar concentration (MAC) of 71%, it is more potent than nitrous oxide (MAC 105%) and its very low blood/gas solubility coefficient (0.14 vs 0.47 of N2O) leads to rapid induction and recovery from anaesthesia. However, its high cost has prevented its use in routine clinical practice. The development of recycling devices, closed circuit anaesthesia systems, new preparations, such as lipid-bound i.v. solutions, and the decrease in cost of xenon indicate that this may change.18 One possible use is as an alternative to potent inhalational anaesthetics in MH-susceptible patients. To test the potential of xenon to trigger MH, we investigated the effect of xenon on muscle specimens of MH-susceptible patients and normal individuals in the IVCT.
![]() |
Methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In vitro contracture test
Muscle bundles were excised from the quadriceps muscle under regional anaesthesia (3 in 1-block: 1% prilocaine plus 0.5% bupivacaine). The IVCT was performed on viable muscle fascicles (twitch response to supramaximal electrical stimulation 10 mN) according to the European MH Group protocol.12 Muscle strips were stretched to 150% of their initial length and electrically stimulated (frequency 0.2 Hz, square pulse, 1 ms duration). After equilibration, administration of halothane (cumulative: 0.5, 1, 2, 3, and 4% v/v equivalent to muscle bath concentrations of 0.11, 0.22, 0.44, 0.66 and 0.88 mM) or caffeine (cumulative: 0.5, 1.0, 1.5, 2.0, 3.0, 4.0 and 32 mM) was started and the baseline tension prior to drug application and at each drug concentration was measured continuously using a force transducer (Fa. RS Biomed Tech, Sinzing, Germany). The halothane concentration was increased at 3-min intervals and monitored by infrared spectroscopy (Iris, Draeger, Luebeck, Germany). Additionally, the concentrations of halothane in the muscle bath were checked by gas chromatography. Caffeine was added cumulatively for each concentration (3 min) from a freshly prepared and warmed stock solution (100 mM at 37°C). The concentration of caffeine in the bath solution was determined by UV-spectrophotometry. MH status was assigned according to the European MH group protocol: MHS (MH susceptible) muscle showed abnormal contractures of
2 mN in at least one muscle specimen exposed to halothane
2 mM and one exposed to caffeine
2 mM, MHE (MH equivocal) only to halothane (MHEh) or caffeine (MHEc) and MHN (normal) muscle strips showed no abnormal response.
Xenon test
A xenon test was performed with one or two viable and supernumerary muscle strips of each individual tested by the standard IVCT. Xenon was obtained from Messer-Griesheim (Duisburg, Germany) in a composition of 70% xenon, 25% oxygen and 5% carbon dioxide which, by its buffering capacities, plays an important role in stabilizing the pH of the bath solution. The preparation, stretching and stimulation of the muscle bundles were done as described for the dignostic IVCT. After equilibration of the muscle bundle (a baseline tension decrease of <2 mN over 10 min) the gassing mixture was switched from carboxygen (95% oxygen, 5% carbon dioxide) to the xenon mixture for 10 min. Baseline tension and evoked twitch force were recorded continuously.
Genetic testing
All families were tested for the following mutations on the RYR1 gene by restriction enzyme analysis or single strand conformation analysis (SSCA) on genomic DNA according to the methods of Brandt and co-workers:19 Cys35Arg, Arg163Cys, Gly248Arg, Gly341Arg, Ile403Met, Tyr522 Ser, Arg533His, Arg552Trp, Arg614Cys, Arg614Leu, Arg2163Cys, Arg2163His, Arg2163Pro, Val2168Met, Thr2206Met, Thr2206Arg, Gly2434Arg, Arg2435His, Arg2435Leu, Arg2454His, Arg2454Cys, Arg2458Cys and Arg2458His. Additionally, all families were screened for the presence of the Arg1068His and Arg1086Cys mutations in the gene encoding the 1-subunit of the L-type voltage-dependent calcium channel (dihydropyridine receptor, DHPR). Each patient from a family with a known mutation was individually tested for the presence of this mutation. Genomic DNA was isolated from blood preserved in ethylenediamintetraacetic acid.
Statistics
The increase in evoked twitch force is presented as the percentage change in comparison to the force before application of the test agents (predrug vs postdrug value). A contracture was determined as the change in baseline tension from the lowest value reached during the test. Inter-group comparisons were performed with the Students t-test for unpaired samples. A P value <0.05 was considered to indicate statistical significance. All analyses were performed with StatView 4.5TM (Abacus Concepts, Berkeley, CA, USA).
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
|
|
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Four of the 11 tested MHS families (36%) carried one of the two most common RYR1 mutations (Arg614Cys or Gly2434Arg). This frequency of mutations in the investigated patients corresponds to those previously reported.19 The samples tested may therefore be considered representative of the MH population.
The application of all three test agents increased the evoked twitch force in the IVCT, a phenomenon presumably due to slight, but controllable elevation of sarcoplasmic calcium release.20 Remarkably, this effect is consistently more pronounced in MHS specimens than in MHN, but the increase induced by xenon in its maximal clinically applied dose is significantly smaller than that observed with either halothane or caffeine. The evoked twitch force increase on application of xenon indicates the substance readily penetrates the muscle strip and lack of penetration is unlikely to be the reason for lack of contracture in response to xenon. Recently, xenon was shown to inhibit plasma membrane calcium-ATPase (PMCA) leading to increased resting [Ca2+]i, enhanced peak [Ca2+]i, and delayed reuptake following stimulation in brain tissue.21 As an increase in intracellular calcium in skeletal muscle could lead to an increase in muscle force and as PMCA is also present in skeletal muscle, this mechanism, independent of RYR1, could be responsible for the observed evoked twitch force increase in accordance with earlier findings of passive non-ryanodine receptor-mediated calcium release in MH.22
In vivo effects of xenon on MH susceptible patients have not yet been tested. In an animal model of MH, the purebred Landrace, Pietrain and Poland China pigs,23 Froeba and co-workers24 have demonstrated the complete absence of any haemodynamic, gas-exchange or metabolic response indicative of MH during 2 h of xenon administration. In contrast, in all animals the subsequent administration of halothane initiated fatal MH episodes. Considering the results of the in vivo experiments in the pig model and the in vitro results in humans, it is reasonable to conclude that xenon (up to 70%) will not trigger MH during anaesthesia in man.
![]() |
Acknowledgements |
---|
![]() |
Footnotes |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
2 Gronert GA, Antognini JF. Malignant hyperthermia. In: Miller RD, ed. Anesthesia, 5th edn. New York: Churchill Livingstone, 1999
3 Ryan JF. Malignant hyperthermia. In: Cote CJ, Ryan JF, Todres ID, Goudsouzian NG, eds. A practice of anesthesia for infants and children, 2nd edn. Philadelphia: Saunders, 1993: 417428
4 Kalow W, Britt BA, Chan FY. Epidemiology and inheritance of malignant hyperthermia. Int Anesthesiol Clin 1979; 17: 11939[Medline]
5 Ørding H. Incidence of malignant hyperthermia in Denmark. Anesth Analg 1985; 64: 7004[Abstract]
6 MacLennan DH, Duff C, Zorzato F, et al. Ryanodine receptor gene is a candidate for predisposition to malignant hyperthermia. Nature 1990; 343: 55961[ISI][Medline]
7 McCarthy TV, Healy JM, Heffron JJ, et al. Localization of the malignant hyperthermia susceptibility locus to human chromosome 19q12-13.2. Nature 1990; 343: 5624[ISI][Medline]
8 Deufel T. Malignant hyperthermia is genetically heterogenetic. Problems in search for molecular genetic markers. Fortschr Med 1992; 110: 49[Medline]
9 Ball SP, Dorkins HR, Ellis FR, et al. Genetic linkage analysis of chromosome 19 markers in malignant hyperthermia. Br J Anaesth 1993; 70: 705[Abstract]
10 Jurkat-Rott K, McCarthy T, Lehmann-Horn F. Genetics and pathogenesis of malignant hyperthermia. Muscle Nerve 2000; 23: 417[ISI][Medline]
11 Iaizzo PA, Klein W, Lehmann Horn F. Fura-2 detected myoplasmic calcium and its correlation with contracture force in skeletal muscle from normal and malignant hyperthermia susceptible pigs. Pflug Arch 1988; 411: 64853[ISI][Medline]
12 The European Malignant Hyperpyrexia Group. A protocol for the investigation of malignant hyperpyrexia (MH) susceptibility. Br J Anaesth 1984; 56: 12679[Abstract]
13 Larach MG. Should we use muscle biopsy to diagnose malignant hyperthermia susceptibility? Anesthesiology 1993; 79: 14[ISI][Medline]
14 Behnke AR, Yarbrough OD. Respiratory resistance, oil-water solubility, and mental effects of argon, compared with helium and nitrogen. Am J Physiol 1939; 126: 40915
15 Lawrence JH, Loomis WF, Tobias CA, Turpin FA. Preliminary observations on the narcotic effect of xenon with a review of values for solubility of gases in water and oil. J Physiol 1946; 105: 197205[ISI]
16 Cullen SC, Gross EG. The anesthetic properties of xenon in animals and human beings, with additional observations on krypton. Science 1951; 113: 5802[ISI]
17 Marx T, Froeba G, Wagner D, Baeder S, Goertz A, Georgieff M. Effects on haemodynamics and catecholamine release of xenon anaesthesia compared with total i.v. anaesthesia in the pig. Br J Anaesth 1997; 78: 3267
18 Marx T, Froeba G, Wagner D, Baeder S, Georgieff M. Retrieval and purification of xenon in anaesthesia. Acta Anaesthesiol Scand 1996; 40: 217
19 Brandt A, Schleithoff L, Jurkat-Rott K, Klingler W, Baur C, Lehmann-Horn F. Screening of the ryanodine receptor gene in 105 malignant hyperthermia families: novel mutations and concordance with the in vitro contracture test. Human Mol Genet 1999; 8: 205562
20 Gallant EM, Mickelson JR, Roggow BD, Donaldson SK, Louis CF, Rempel WE. Halothane-sensitivity gene and muscle contractile properties in malignant hyperthermia. Am J Physiol 1989; 257: C7816.
21 Horn JL, Janicki PK, Franks JJ. Lack of effect of flurothyl, a non-anesthetic fluorinated ether, on rat brain synaptic plasma membrane calcium-ATPase. Life Sci 1998; 64: 17983
22 Louis CF, Zualkernan K, Roghair T, Mickelson JR. The effects of volatile anesthetics on calcium regulation by malignant hyperthermia-susceptible sarcoplasmic reticulum. Anesthesiology 1992; 77: 11425[ISI][Medline]
23 Lucke JN, Hall GM, Lister D. Porcine malignant hyperthermia. I: Metabolic and physiological changes. Br J Anaesth 1976; 48: 297304[Abstract]
24 Froeba G, Marx T, Pazhur JR, et al. Xenon does not trigger malignant hyperthermia in susceptible swine. Anesthesiology 1999; 91: 104752[ISI][Medline]
25 Gallant EM, Godt RE, Gronert GA. Mechanical properties of normal and malignant hyperthemia susceptible porcine muscle: effects of halothane and other drugs. J Pharmacol Exp Ther 1980; 213: 916[Abstract]
26 Gronert GA, Heffron JJ, Taylor SR. Skeletal muscle sarcoplasmic reticulum in porcine malignant hyperthermia. Eur J Pharmacol 1979; 58: 17987[ISI][Medline]
27 Iaizzo PA, Lehmann Horn F, Taylor SR, Gallant EM. Malignant hyperthermia: effects of halothane on the surface membrane. Muscle Nerve 1989; 12: 17883[ISI][Medline]