025 Impact of a quality procedure on the survival of patients with malignant hyperthermia

Background and Objectives The mortality rate of malignant hyperthermia (MH) was 64% before the US Food and Drug Administration approved intravenous dantrolene in 1980. In France, a national formal quality procedure relative to the treatment of MH was issued in 1989 and updated in November 1999. It made the availability of an adequate stock of dantrolene compulsory and provided guidelines for MH management. Our objective was to analyse trends in mortality in proven MH cases in France. Programme We retrospectively reviewed the database of the MH unit at Lille hospital. The inclusion criteria for our review were the following: at least one positive halothane test (in vitro contracture test (IVCT)) in the surviving subject or a close relative and/or a MH causative mutation in the RyR1 gene. Informed consent was obtained from all patients and/or relatives. Statistical analysis was performed using SAS 9.1.3 Service Pack 4. Results There were a total of 115 MH cases between 1969 and 2007 (see Abstract 25 Table 1). Overall mortality was 31%. Mortality decreased significantly over time from 59% to 7%. The last two deaths occurred in 1995 and 2004. We observed no serious sequelae in survivors. Neither median age nor sex ratio (64% male) varied significantly over the four time periods; neither influenced mortality. Patients received a halogenated anaesthetic (≥90%) and/or succinylcholine (50%). Succinylcholine use decreased over time and was higher in the deceased (74%) than in survivors (43%). Discussion A strength of our study was that MH diagnosis was proven by IVCT and/or genetic analysis. The most striking observation was the trend towards zero mortality. This result does not support the recent report from the North American Malignant Hyperthermia Registry of the Malignant Hyperthermia Association1 which concluded that modern US anaesthetic practice did not prevent MH-associated cardiac arrest and death in predominantly young, healthy patients undergoing low - to intermediate-risk surgical procedures. We conclude that the positive impact on survival in our study was probably related to the national formal quality procedure for MH instigated by the French health authorities. Introduction La mortalite de l9hyperthermie maligne anesthesique (HM) etait chiffree a 64% avant le dantrolene injectable (1980). La France a redige une procedure qualite sous forme de circulaire, en 1989, modifiee en 1999 (Circulaire DGS/DH du 18 novembre 1999 relative au traitement de l9hyperthermie maligne (HM) peranesthesique). Le but de ce travail est d9etudier l9evolution de la mortalite au decours d9une crise HM prouvee par des tests de contracture halothane cafeine (CHCT) et/ou la presence d9une mutation causale HM. Materiel et methodes Analyse de la base de donnees du centre HM de Lille. Les criteres d9inclusion sont l9existence d9au moins un test a l9halothane positif chez le sujet survivant ou un parent proche, et/ou l9existence d9une mutation responsable HM dans le gene RYRl. Les donnees sont recueillies aupres des anesthesistes. Dans tous les cas, un consentement eclaire est recueilli. Une analyse statistique a ete realisee avec le logiciel SAS. Resultats Cent quinze cas inclus entre 1969 et 2007, repartis en 4 periodes: - 2000. La mortalite globale est de 31% (Tableau) avec une diminution significative (de 59 a 7%). Les 2 derniers deces ont eu lieu en 1995 et 2004. On n9observe pas de sequelles graves chez les survivants. L9âge median etait de 16 ans (0.5–70), ne varie pas en fonction du temps et n9influence pas la mortalite. Le rapport homme-femme (64% d9hommes) etait stable au cours du temps et sans influence sur la mortalite. Tous les patients ont recu un anesthesique halogene (>90%) et/ou de 1a celocurine (50%). L9utilisation de la celocurine diminue au cours du temps. Elle est plus souvent presente chez les patients decedes (74%) que chez les survivants (43 °lo). Discussion L9originalite de l9etude repose sur le caractere prouve des crises HM. L9evolution vers une mortalite proche de 0 est le fait le plus remarquable. Il est a mettre en parallele avec une etude recemment publiee1 de cas declares au registre HM americain et consideres « comme tres probable ou presque certains ». Cet article conclut: « la pratique US moderne de l9anesthesie ne previent pas les morts HM chez des sujets jeunes et en bonne sante pour des chirurgies a risque bas ou intermediaire ». Les resultats rapportes ici montrent l9impact positif en termes de survie sans sequelle des circulaires francaises relatives au traitement de l9HM qui rendent obligatoires la disponibilite d9un stock adequat de dantrolene et des procedures de prise en charge d9une crise.