TY - JOUR T1 - Towards gas narcosis monitoring in compressed gas diving (PhD Academy Award) JF - British Journal of Sports Medicine JO - Br J Sports Med DO - 10.1136/bjsports-2022-106175 SP - bjsports-2022-106175 AU - Xavier C Vrijdag Y1 - 2022/12/30 UR - http://bjsm.bmj.com/content/early/2022/12/29/bjsports-2022-106175.abstract N2 - I aimed to develop an objective and reliable measurement tool to quantify subanaesthetic levels of gas narcosis in scuba divers. I investigated pupillometry, critical flicker fusion frequency and novel quantitative electroencephalogram (EEG) algorithms.Divers venturing underwater, either for work or pleasure, may experience narcotic effects caused by their breathing gases. The onset of narcosis symptoms is expected around 30 m (405 kPa) when breathing air. The principal hazard of gas narcosis is euphoria, overconfidence and loss of judgement. This may cause the diver to become less alert, take extra risks and start a chain of events culminating in a severe diving accident. No early warning signal is available. Therefore, an objective method to detect narcosis could improve diver safety by characterising the related effects of each component in the breathing gas mixture, allowing the diver to make informed choices about gas mix composition and facilitating related research.In three studies involving 12 sport divers each, participants were exposed to: (1) 3 low-dose inspired fractions of nitrous oxide (20%, 30% and 40%) blinded, in random order, as a normobaric research surrogate for hyperbaric nitrogen; (2) air and heliox (helium–oxygen mixture) at 284 … ER -