Vincent Varlet

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Projects FNS

Diagnosis and Interpretation of Vascular Embolism gas composition in Scuba Diving
2019 - 2021 (15 mois)
Applicant : Vincent VARLET
Scuba diving, practiced as hobby or professional activity, involves some inherent risks, and because of these risks it requires special training. These risks include decompression sickness, arterial air embolism, and of course drowning. There are also effects of diving, such as nitrogen narcosis that can contribute to the cause of these problems. Each year, an estimated average of 200 scuba diving fatalities occurs and in this unconventional human environment information to document what has happened is scarce. The dead body is often the unique way to rebuild the truth but the forensic knowledge of scuba diving fatalities is random, incomplete and, sometimes wrong. It has become crucial to investigate the fatalities linked to this practice in order to give an answer to the relatives and to improve the prevention and forensic diagnoses.

This project aims to validate the intracardiac gaseous CO2 concentration as a reliable indicator to support the fatal scenario hypothesized from diving profiles examinations and autopsy findings. Until now, it was thought that the gas embolism was N2 due to release of diving gas (mainly composed by air mixtures). However, we aim to show that the diagnosis should be based on CO2 rather than N2 and that we can confirm or invalidate the forensic diagnosis. A working network has been developed among several Mediterranean forensic centers (France, Spain and Italy) in order to sample intracadaveric gases in case of scuba diving fatality.

The forensic diagnoses improvements in case of scuba diving fatalities will be not only essential for scuba diving fatality management but also very important to better understand the physiological mechanisms implied in fatal gas embolism in general, also in clinical medicine. It will be helpful to prepare and improve resuscitation procedures. Indeed, gas physiology and methodological protocols are of strong interest for baromedical medicine. These missing information are crucial for teaching and prevention to better target risky behaviors.

Others projects

Evaluation du mésusage de la cigarette électronique : vapotage de cannabis et évaluation de la contamination passive
2014 - 2015 (12 mois)
grant-giving organisation : CHUV - DUMSC (Switzerland)
Applicant : Vincent Varlet, Aurélie Berthet, Bernard Favrat
Other partners : Aurélien Thomas, Christian Giroud, Grégory Plateel, Marc Augsburger, Frank Sporkert

Carbon monoxide poisonings: exploring new approaches for quantification and evaluating measurement errors from an analytical and epidemiological point of view
2017 - 2020 (36 mois)
grant-giving organisation : Gas Safety Trust (Great Britain)
Applicant : Vincent Varlet
Every year, approximately 50,000 emergency department (ED) visits and 2,741 deaths in the US are due to carbon monoxide (CO) poisoning, 350 in Europe, 250 in Australia and 3,200 in Japan. CO is a gaseous, diatomic molecule with no taste, colour or odour. However, its toxicokinetic and toxicodynamic mechanisms are still not sufficiently known, with CO having the potential of causing severe adverse health effects involving the respiratory, cardio-circulatory and neurological systems, which can be lethal.
This project aims to tackle the raised issues from a scientific standpoint by following a path that links the toxicological to the epidemiological investigation.
1. We plan to develop and validate an alternative analytical method for more accurate CO poisoning determination for clinical and forensic applications, to help decrease misdiagnosis due to the inconsistencies between symptoms and COHb levels.
2. We want to determine and quantify the influence of storage parameters on changes in COHb/CO concentrations over time and aid in creating a model that allows accounting for these alterations during the interpretation of results from CO poisoning determinations in individual measurements. This should also decrease the number of cases erroneously not attributed to CO as a cause of morbidity or mortality.
3. We plan to identify the gaps in CO exposure assessments, determining and quantifying measurement error arising from recent methodological and toxicological advances. This will enable us to create an overview of current practices and frequent errors in CO exposure assessment as well as generating a tool to correct for a part of these errors.
4. We would like to study the improvements that the alternative biomarker to characterize CO poisonings might have, with the general aim of increasing correctly diagnosed cases and increasing the number of treatable patients, reducing injuries and fatalities, but also establish improved exposure assessments, leading to better guidelines to help prevent CO poisonings.

Contracts and Mandates

Aerosol gaseous composition analyses

2013 - 2013
grant-giving organisation : Office Fédéral de la Santé Publique OFSP (Switzerland)


grant-giving organisation : Autorités judiciaires vaudoises, valaisannes, fribourgeoises, jurassiennes, neuchâteloises, tessinoises (Switzerland)

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