Bubble measurement techniques
Boussuges, A.; Tillmans, F. (2017). Bubble measurement techniques, in: Balestra, C. et al. The science of diving. Things your instructor never told you. pp. [137-155] In: Balestra, C.; Germonpré, P. (2017). The science of diving. Things your instructor never told you. Lambert Academic Publishing/Éditions Acrodacrolivres: Villers-la-Ville. ISBN 978-2-512007-36-4. [262] pp., more |
| Authors | | Top | - Boussuges, A.
- Tillmans, F., more
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| Abstract | Nitrogen desaturation in SCUBA divers leads to the production of circulating gas bubbles during the decompression period and over the ensuing minutes and hours (up to 3 hours post-dive). Since the 1970’s and the studies of Guillerm and Masurel in France, and Smith and Spencer in the USA, these bubbles have been detected using ultrasonographic techniques. A system of classification to assess the quantity of circulating bubbles has been developed by several research groups. The bubble scores or scales are based on the number of bubbles with respect to the cardiac cycle, commonly referred to as heartbeat. Several studies have investigated the correlation between bubble rating and the probability of a decompression accident. Although the significance of this correlation is debated when bubbles are detected, all of these studies agree that the risk of DCI is low in the absence of circulating bubbles. Bubble screening could therefore mainly be used as a safety indicator for validating diving profiles: a decompression profile that does not induce the production of bubbles in a large population of divers may be considered a safe profile. The main quality of a bubble screening procedure is therefore its sensitivity. On the other hand, echographic techniques have a low specificity to predict DCS. Indeed, circulating bubbles are frequently observed after diving, in subjects without any resulting clinical disorders. In addition to avoiding DCS, the aim here is to limit decompression stress as evaluated by circulating bubbles post-dive. The aim of this chapter is to discuss various techniques used to screen circulating bubbles, their applications, and their limitations. |
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