Circulating Venous Bubbles in Recreational Diving: Relationships with Age, Weight, Maximal Oxygen Uptake and Body Fat Percentage

Carturan, D.; Boussuges, Alain; Burnet, Henri; Fondarai, J; Vanuxem, P; Gardette, B

doi:10.1055/s-2007-971154

Cited by 30 publications

(25 citation statements)

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“…[84][85][86] The benefit of physical conditioning was also suggested by the association of low VGE incidence with divers in whom maximal oxygen consumption was high. 87 In summary, the effect of exercise before decompression appears to depend on the intensity of exercise, the interval between exercise and decompression, and physical conditioning. Studies of anaerobic exercise before altitude exposure in humans and animals found evidence of increased DCS risk if the exercise took place immediately or within several hours of decompression but that the risk was not increased after a 1-day interval.…”

Section: Exercise Before Pressure Exposure: Bubble Nucleationmentioning

confidence: 99%

Mechanisms and Risks of Decompression

Vann¹

2004

Bove and Davis' Diving Medicine

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Section: Exercise Before Pressure Exposure: Bubble Nucleationmentioning

confidence: 99%

Mechanisms and Risks of Decompression

Vann¹

2004

Bove and Davis' Diving Medicine

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“…There was a bigger variation in dive experience and we expect these divers in average to be less experienced, although we can not confirm this. These data also contained a wide varity of other individual parameters like age, fat percentage and fitness level, that are known to influence the Doppler results [4]. Additionally these exposures are predominately multi-day diving, which in the Croatia study were excluded.…”

Section: Discussionmentioning

confidence: 99%

Parameter estimation of the copernicus decompression model with venous gas emboli in human divers

Gutvik

Dunford²,

Dujić

et al. 2010

Med Biol Eng Comput

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Decompression Sickness (DCS) may occur when divers decompress from a hyperbaric environment. To prevent this, decompression procedures are used to get safely back to the surface. The models whose procedures are calculated from, are traditionally validated using clinical symptoms as an endpoint. However, DCS is an uncommon phenomenon and the wide variation in individual response to decompression stress is poorly understood. And generally, using clinical examination alone for validation is disadvantageous from a modeling perspective. Currently, the only objective and quantitative measure of decompression stress is Venous Gas Emboli (VGE), measured by either ultrasonic imaging or Doppler. VGE has been shown to be statistically correlated with DCS, and is now widely used in science to evaluate decompression stress from a dive. Until recently no mathematical model has existed to predict VGE from a dive, which motivated the development of the Copernicus model. The present article compiles a selection experimental dives and field data containing computer recorded depth profiles associated with ultrasound measurements of VGE. It describes a parameter estimation problem to fit the model with these data. A total of 185 square bounce dives from DCIEM, Canada, 188 recreational dives with a mix of single, repetitive and multi-day exposures from DAN USA and 84 experimentally designed decompression dives from Split Croatia were used, giving a total of 457 dives. Five selected parameters in the Copernicus bubble model were assigned for estimation and a non-linear optimization problem was formalized with a weighted least square cost function. A bias factor to the DCIEM chamber dives was also included. A Quasi-Newton algorithm (BFGS) from the TOMLAB numerical package solved the problem which was proved to be convex. With the parameter set presented in this article, Copernicus can be implemented in any programming language to estimate VGE from an air dive.

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“…Mit Einführung der Doppler-Diagnostik gelang es, Inertgasblasen nach Tauchgängen zu detektieren, und inzwischen wurden solche Blasen auch bei asymptomatischen Probanden vielfach nachgewiesen [8,9,11,14]. Die Gefahr pathologischer Effekte dieser Inertgasblasen ist abhängig von deren Menge und Lokalisation.…”

Section: Physiologische Kardiovaskuläre Effekte Des Tauchensunclassified

“…Darüber hinaus konnte Doppler-sonographisch gezeigt werden, dass es bei übergewichtigen Tauchern während bzw. unmittelbar nach der Dekompression zu einer vermehrten Gasblasenbildung kommt [8,9]. Erklärend sei hier erwähnt, dass prinziTabelle 2.…”

Section: Hyperlipidämie Und Adipositasunclassified

Tauchen und Herz

Muth

Tetzlaff²

2004

Herz

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Diving with self-contained underwater breathing apparatus (scuba) has become a popular recreational sports activity throughout the world. A high prevalence of cardiovascular disorders among the population makes it therefore likely that subjects suffering from cardiovascular problems may want to start scuba diving. Although scuba diving is not a competitive sport requiring athletic health conditions, a certain medical fitness is recommended because of the physical peculiarities of the underwater environment. Immersion alone will increase cardiac preload by central blood pooling with a rise in both cardiac output and blood pressure, counteracted by increased diuresis. Exposure to cold and increased oxygen partial pressure during scuba diving will additionally increase afterload by vasoconstrictive effects and may exert bradyarryhthmias in combination with breath-holds. Volumes of gas-filled body cavities will be affected by changing pressure (Figure 1), and inert gas components of the breathing gas mixture such as nitrogen in case of air breathing will dissolve in body tissues and venous blood with increasing alveolar inert gas pressure. During decompression a free gas phase may form in supersaturated tissues, resulting in the generation of inert gas microbubbles that are eliminated by the venous return to the lungs under normal circumstances. Certain cardiovascular conditions may have an impact on these physiological changes and pose the subject at risk of suffering adverse events from scuba diving. Arterial hypertension may be aggravated by underwater exercise and immersion. Symptomatic coronary artery disease and symptomatic heart rhythm disorders preclude diving. The occurrence of ventricular extrasystoles according to Lown classes I and II, and the presence of atrial fibrillation are considered relative contraindications in the absence of an aggravation following exercise. Asymptomatic subjects with Wolff-Parkinson-White syndrome may be allowed to dive, but in case of paroxysmal supraventricular tachycardia they must refrain from diving. Pacemakers will fail with increasing pressure, but some manufacturers have proven their products safe for pressure equivalents of up to 30 m of seawater, so that patients may dive uneventfully when staying within the 0-20 m depth range. Significant aortic or mitral valve stenosis will preclude diving, whereas regurgitation only will not be a problem. Right-to-left shunts have increasingly gained attention in diving medicine, since they may allow venous gas microbubbles to spill over to the arterial side of the circulation enabling the possibility of arterial gas embolism. Significant shunts thus preclude diving. The highly prevalent patent foramen ovale is considered a relative contraindication only when following certain recommendations for safe diving (Table 2). Metabolic disorders are of concern, since adiposity is associated with both, higher bubble grades in Doppler ultrasound detection after scuba dives when compared to normal subjects, and an increased epidemiologic ris...

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Circulating Venous Bubbles in Recreational Diving: Relationships with Age, Weight, Maximal Oxygen Uptake and Body Fat Percentage

Cited by 30 publications

References 0 publications

Mechanisms and Risks of Decompression

Mechanisms and Risks of Decompression

Parameter estimation of the copernicus decompression model with venous gas emboli in human divers

Tauchen und Herz

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