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Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study

PURPOSE: Data regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight in venous gas emboli (VGE) dynamics. METHODS: Diving practices of ten technical divers were o...

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Autores principales: Balestra, Costantino, Guerrero, François, Theunissen, Sigrid, Germonpré, Peter, Lafère, Pierre
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8627581/
https://www.ncbi.nlm.nih.gov/pubmed/34839432
http://dx.doi.org/10.1007/s00421-021-04856-5
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author Balestra, Costantino
Guerrero, François
Theunissen, Sigrid
Germonpré, Peter
Lafère, Pierre
author_facet Balestra, Costantino
Guerrero, François
Theunissen, Sigrid
Germonpré, Peter
Lafère, Pierre
author_sort Balestra, Costantino
collection PubMed
description PURPOSE: Data regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight in venous gas emboli (VGE) dynamics. METHODS: Diving practices of ten technical divers were observed. They performed a series of three consecutive daily dives around 100 m. VGE counts were measured 30 and 60 min after surfacing by both cardiac echography and subclavian Doppler graded according to categorical scores (Eftedal–Brubakk and Spencer scale, respectively) that were converted to simplified bubble grading system (BGS) for the purpose of analysis. Total body weight and fluids shift using bioimpedancemetry were also collected pre- and post-dive. RESULTS: Depth-time profiles of the 30 recorded man-dives were 97.3 ± 26.4 msw [range: 54–136] with a runtime of 160 ± 65 min [range: 59–270]. No clinical decompression sickness (DCS) was detected. The echographic frame-based bubble count par cardiac cycle was 14 ± 13 at 30 min and 13 ± 13 at 60 min. There is no statistical difference neither between dives, nor between time of measurements (P = 0.07). However, regardless of the level of conservatism used, a high incidence of high-grade VGE was detected. Doppler recordings with the O’dive were highly correlated with echographic recordings (Spearman r of 0.81, P = 0.008). CONCLUSION: Although preliminary, the present observation related to real CCR deep dives questions the precedence of decompression algorithm over individual risk factors and pleads for an individual approach of decompression.
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spelling pubmed-86275812021-11-29 Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study Balestra, Costantino Guerrero, François Theunissen, Sigrid Germonpré, Peter Lafère, Pierre Eur J Appl Physiol Original Article PURPOSE: Data regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight in venous gas emboli (VGE) dynamics. METHODS: Diving practices of ten technical divers were observed. They performed a series of three consecutive daily dives around 100 m. VGE counts were measured 30 and 60 min after surfacing by both cardiac echography and subclavian Doppler graded according to categorical scores (Eftedal–Brubakk and Spencer scale, respectively) that were converted to simplified bubble grading system (BGS) for the purpose of analysis. Total body weight and fluids shift using bioimpedancemetry were also collected pre- and post-dive. RESULTS: Depth-time profiles of the 30 recorded man-dives were 97.3 ± 26.4 msw [range: 54–136] with a runtime of 160 ± 65 min [range: 59–270]. No clinical decompression sickness (DCS) was detected. The echographic frame-based bubble count par cardiac cycle was 14 ± 13 at 30 min and 13 ± 13 at 60 min. There is no statistical difference neither between dives, nor between time of measurements (P = 0.07). However, regardless of the level of conservatism used, a high incidence of high-grade VGE was detected. Doppler recordings with the O’dive were highly correlated with echographic recordings (Spearman r of 0.81, P = 0.008). CONCLUSION: Although preliminary, the present observation related to real CCR deep dives questions the precedence of decompression algorithm over individual risk factors and pleads for an individual approach of decompression. Springer Berlin Heidelberg 2021-11-28 2022 /pmc/articles/PMC8627581/ /pubmed/34839432 http://dx.doi.org/10.1007/s00421-021-04856-5 Text en © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021 This article is made available via the PMC Open Access Subset for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.
spellingShingle Original Article
Balestra, Costantino
Guerrero, François
Theunissen, Sigrid
Germonpré, Peter
Lafère, Pierre
Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title_full Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title_fullStr Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title_full_unstemmed Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title_short Physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
title_sort physiology of repeated mixed gas 100-m wreck dives using a closed-circuit rebreather: a field bubble study
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8627581/
https://www.ncbi.nlm.nih.gov/pubmed/34839432
http://dx.doi.org/10.1007/s00421-021-04856-5
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