L’argon : utilisations, toxicité et stratégie analytique en toxicologie médicolégale

Abstract

Résumé -Bien qu'intrinsèquement non toxiques, les gaz nobles comme l'argon entraînent à fortes concentrations une déplétion d'oxygène pouvant mener jusqu'à l'asphyxie. Si l'argon se retrouve dans la circulation générale, celui-ci peut même être responsable d'embolies parfois fatales. Cependant, les propriétés d'inerties physicochimiques de ce gaz le rendent très utile dans de nombreuses applications actuelles. Ces applications étant en constante augmentation, il n'est pas rare d'observer proportionnellement des intoxications parfois létales liées à ce gaz. Ainsi, devant le manque d'harmonisation des prélèvements d'échantillons biologiques afin de mettre en évidence de telles intoxications aux gaz nobles et devant l'augmentation du nombre de cas, il devient nécessaire d'établir un état des lieux sur l'utilisation de l'argon, sa toxicité et la stratégie analytique à adopter dans le contexte médico-légal. Mots clés :Argon, gaz noble, échantillonnage de gaz, analyse de gaz Abstract -Even though noble gases such as argon are intrisically non-toxic, they will enhance an oxygen-depletion at high concentrations. This depletion may lead to asphyxia. If argon is found in blood flow, it could be responsible of an embolism. However, its inert physicochemical properties appear to be very useful to a wide range of current applications. The rise of these applications induces a proportionnal increase of lethal intoxications due to this gas. Thus, as no standardization of biological samples exists, and knowing the increase of argon intoxication cases, it seems necessary to establish an incoming inventory of fixture concerning the use of argon. It will confirm its toxicity properties and will highlight other intoxications due to noble gas. This should lead to a new analytical strategy suitable to the forensic context.

Helium poisoning: new procedure for sampling and analysis

“…Tissue samples were taken according to the particular standard procedure (rapid sampling during autopsy in HS vials of 10 or 20 mL, sealed with aluminium cap and cold storage). Gaseous samples were taken following the protocol of noble gases poisoning or intracadaveric gases [36][37][38].…”

“…Therefore, as a single lung biopsy cannot be representative of the whole organ, protocols using lung lobectomy (mono, bi, trilobular biopsies) have been developed to avoid false negative results due to sampling. These protocols have been well described [3,24,36,37,40,41] but some authors found them too sophisticated compared to rapid lung biopsy in HS [32]. However, this comment was formulated because the HS lungs biopsies were detected as He positive.…”

“…Nevertheless, the protocol of He release from a whole lung or lung lobe requires a standardization because several approaches were described with different containers types (plastic boxes, plastic bags, etc.). Briefly, the technique requires the immersion of the whole biopsy in water and a container [36,37]. The aim is to agitate/press the biopsy to mechanically release trapped residual He, thanks to direct manual pressure [3] or with sticks [40].…”

The Place of Gas Analysis in Forensic Toxicology

“…Gas sampling under laser guidance is an efficient and precise tool to recover gas samples located into the body [19]. For suicide with noble gas, the samples of interest are gastric gas, tracheal gas and lungs samples [20]. These matrices can easily be sampled during conventional autopsy (with airtight gas syringe for gaseous samples) without the aid of forensic imaging.…”