The risk for developing decompression-related symptoms was increasing significantly with an additional Odds ratio of 2.7 per bubble grade and a maximum risk of 43% to develop symptoms when bubbles are as frequently seen as at least 1 per cm 2 in 2D echocardiography. In previous studies, a high number of detectable bubbles after ascent in up to 50% of divers was related to symptoms of decompression sickness in 2–11% of sports dives and up to around 40% of decompression and mixed gas commercial dives. Dive depth, time and ascent speed are key factors for inert gas bubbling, although modified by individual factors, that can lead to so-called “undeserved” diving accidents despite following real time dive computer ascent protocols. However, asymptomatic inert gas bubbles arise frequently-up to the majority of air dives-even within sports diving limits, and there is a wide inter- and intraindividual variety in developing bubbles and decompression symptoms, despite following dive computer profiles that calculate ascent schedules from depth-time integrals. To avoid this, decompression tables and dive computers provide empiric guidance on ascent time, depending on depth and dive time. This results in microbubbling and macrobubbling and ultimately can lead to symptoms of decompression sickness. This qualitative information can be important in self-evaluating decompression stress and assessing measures for increased diving safety.ĭuring ascent in scuba diving, inert gases such as nitrogen can become supersaturated in tissues and blood. Despite accurate bubble grading is impossible in dive-site conditions, relevant high bubble grades can be detected by non-professionals. Audio Doppler self-assessment can be learned by non-professionals in a single teaching intervention. 6 months after the training and 4.5 months after the last measurement, the achieved Doppler skill level remained stable. Bubble detection sensitivity of audio Doppler self-assessments, compared to an experienced examiner, was 62% at subclavian and 73% at precordial position. Dive-site audio-Doppler-grading underestimated echo-derived bubble grades. The specificity of audio bubble detection in combination of both detection sites was 95%, and sensitivity over all grades was 40%, increasing with higher bubble grades. ![]() In all dives (average maximum depth 22 m dive time 44 min), 33% of all echocardiography measurements revealed bubbles. ![]() Assessment before and after air dives within sports diving limits was made through 684 audio Doppler measurements in dive-site conditions by both trained divers and a medical professional, plus additional 2D-echocardiography reference. We taught audio Doppler self-assessment of subclavian and precordial probe position to 41 divers in a 45-min standardized, didactically optimized training. If those non-professionals were able to learn audio Doppler self-assessment for bubble grading, such skill could provide significant information on individual decisions with respect to diving safety. Professional audio Doppler bubble measurements are not available to sports scuba divers. ![]() Observing modern decompression protocols alone cannot fully prevent diving injuries especially in repetitive diving.
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