Pre-dive Whole-Body Vibration Better Reduces Decompression-Induced Vascular Gas Emboli than Oxygenation or a Combination of Both

Purpose: Since non-provocative dive profiles are no guarantor of protection against decompression sickness, novel means including pre-dive “preconditioning” interventions, are proposed for its prevention. This study investigated and compared the effect of pre-dive oxygenation, pre-dive whole body vibration or a combination of both on post-dive bubble formation. Methods: Six healthy volunteers performed 6 no-decompression dives each, to a depth of 33 mfw for 20 min (3 control dives without preconditioning and 1 of each preconditioning protocol) with a minimum interval of 1 week between each dive. Post-dive bubbles were counted in the precordium by two-dimensional echocardiography, 30 and 90 min after the dive, with and without knee flexing. Each diver served as his own control. Results: Vascular gas emboli (VGE) were systematically observed before and after knee flexing at each post-dive measurement. Compared to the control dives, we observed a decrease in VGE count of 23.8 ± 7.4% after oxygen breathing (p < 0.05), 84.1 ± 5.6% after vibration (p < 0.001), and 55.1 ± 9.6% after vibration combined with oxygen (p < 0.001). The difference between all preconditioning methods was statistically significant. Conclusions: The precise mechanism that induces the decrease in post-dive VGE and thus makes the diver more resistant to decompression stress is still not known. However, it seems that a pre-dive mechanical reduction of existing gas nuclei might best explain the beneficial effects of this strategy. The apparent non-synergic effect of oxygen and vibration has probably to be understood because of different mechanisms involved

Pre-dive whole-body vibration better reduces decompression-induced Vascular Gas Emboli than oxygenation or a combination of both.

Purpose: Since non-provocative dive profiles are no guarantor of protection against decompression sickness, novel means including pre-dive preconditioning interventions, are proposed for its prevention. This study investigated and compared the effect of pre-dive oxygenation, pre-dive whole body vibration or a combination of both on post-dive bubble formation. Methods: 6 healthy volunteers performed 6 no-decompression dives each, to a depth of 33 mfw for 20 minutes (3 control dives without preconditioning and 1 of each preconditioning protocol) with a minimum interval of 1 week between each dive. Post-dive bubbles were counted in the precordium by two-dimensional echocardiography, 30 and 90 minutes after the dive, with and without knee flexing. Each diver served as his own control.Results: Vascular gas emboli (VGE) were systematically observed before and after knee flexing at each post-dive measurement. Compared to the control dives, we observed a decrease in VGE count of 23.8±7.4% after oxygen breathing (p<0.05), 84.1±5.6% after vibration (p<0.001), and 55.1±9.6% after vibration combined with oxygen (p<0.001). The difference between all preconditioning methods was statistically significant.Conclusions: The precise mechanism that induces the decrease in post-dive VGE and thus makes the diver more resistant to decompression stress is still not known. However, it seems that a pre-dive mechanical reduction of existing gas nuclei might best explain the beneficial effects of this strategy. The apparent non-synergic effect of oxygen and vibration has probably to be understood because of different mechanisms involved

Hyperbaric oxygen therapy for acute noise-induced hearing loss: evaluation of different treatment regimens.

Impulse noise from firearms is a common cause of acute acoustic trauma (AAT), which is characterized by high-frequency hearing loss and tinnitus. Various treatment modalities have been proposed, some combining medical treatment with hyperbaric oxygen (HBOT) in various ways. We have reviewed the therapeutic effect of primary protocols, with or without HBOT, used in our hospital.info:eu-repo/semantics/publishe

Inert gas Narcosis

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Pulmonary barotrauma in divers during emergency free ascent training: review of 124 cases.

Experience from treating diving accidents indicates that a large proportion of divers suffering from pulmonary barotraumas (PBT) or arterial gas embolism (AGE) were engaged in training dives, specifically emergency free ascent (EFA). We tried to verify this relationship and to calculate, if possible, the risk associated with normal recreational dives, training dives, and EFA training dives.Journal Articleinfo:eu-repo/semantics/publishe

The effect of general anaesthesia and neuromuscular blockade on Eustachian tube compliance: a prospective study.

The most common complications of hyperbaric oxygen treatment (HBOT) are related to pressure changes on gas-containing cavities. Therefore, inability to auto-inflate the middle ear may result in transient or permanent hearing loss. However, it seems that middle ear barotrauma (MEBt) does not develop more often in mechanically ventilated patients than in ambulatory patients. This might be explained by deep sedation of these patients. Therefore, the aim of this study was to determine whether anaesthesia and/or neuromuscular blockade can influence Eustachian tube (ET) function.info:eu-repo/semantics/publishe

Patent Foramen Ovale (PFO), personality traits, and iterative decompression sickness. Retrospective analysis of 209 cases

Introduction: There is a need to evaluate the influence of risk factors such as patency of foramen ovale (PFO) or "daredevil" psychological profile on contra-indication policy after a decompression sickness (DCS). Methods: By crossing information obtained from Belgian Hyperbaric Centers, DAN Emergency Hotline, the press, and Internet diving forums, it was possible to be accountable for the majority if not all DCS, which have occurred in Belgium from January 1993 to June 2013. From the available 594 records we excluded all cases with tentative diagnosis, medullary DCS or unreliability of reported dive profile, leaving 209 divers records with cerebral DCS for analysis. Demographics, dive parameters, and PFO grading were recorded. Twenty-three injured divers were tested using the Zuckerman's Sensation Seeking Scale V and compared to a matched group not involved in risky activities. Results: 41.2% of all injured came for iterative DCS. The average depth significantly increases with previous occurrences of DCS (1st DCS: 31.8 ± 7.9 mfw; 2nd DCS: 35.5 ± 9.8 mfw; 3rd DCS: 43.4 ± 6.1 mfw). There is also an increase of PFO prevalence among multiple injured divers (1st DCS: 66.4% 2nd & 3rd DCS: 100%) with a significant increase in PFO grade. Multiple-times injured significantly scored higher than control group on thrill and adventure seeking (TAS), experience seeking, boredom susceptibility and total score. Conclusion: There is an inability of injured diver to adopt conservative dive profile after a DCS. Further work is needed to ascertain whether selected personality characteristics or PFO should be taken into account in the clearance decision to resume diving.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Functional comparison between critical flicker fusion frequency and simple cognitive tests in subjects breathing air or oxygen in normobaria.

Measurement of inert gas narcosis and its degree is difficult during operational circumstances, hence the need for a reliable, reproducible and adaptable tool. Although being an indirect measure of brain function, if reliable, critical flicker fusion frequency (CFFF) could address this need and be used for longitudinal studies on cortical arousal in humans.Comparative StudyJournal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Field study of anthropomorphic and muscle performance changes among elite skippers following a transoceanic race.

Background: Ocean racing has become increasingly demanding, both physically and psychologically. The aim of the study was to assess global changes after a transoceanic race.Materials and methods: Eight male sailors were evaluated pre- and post-race through anthropometric measurements (weight, skinfold, girth at different level and estimated body fat percentage), multifrequency tetrapolar bioelectrical impedance, muscular performance, visual analogic scale for perceived fatigue and Critical Flicker Fusion Frequencies for cerebral arousal.Results: Compared to pre-race values, a significant decrease in body weight (–3.6 ± 1.4%, p = 0.0002) and body composition with reduction of body fat percentage (–15.1 ± 3.5%, p < 0.0001) and fat mass (–36.4 ± 31.4%, p = 0.022) was observed. Muscle performance of the upper limb was preserved. In the lower limb, monohulls skippers showed a significant reduction of jump height (–6.6 ± 4.8%, p = 0.022), power (–11.7 ± 7.3%, p = 0.011) and speed (–14.6 ± 7.4%, p = 0.0006) while a multihulls skipper showed a gain in speed (+0.87%), power (+8.52%), force (+11%) resulting in a higher jump height (+1.12%). These changes were inversely correlated with sea days (Pearson r of –0.81, –0.96 and –0.90,respectively, p < 0.01).Conclusions: Changes in body weight and composition are consistent with previous data indicating a probable negative energy balance. The main finding demonstrates a difference in muscular conditioning between upper and lower limbs that might be explained by differential workload related to boat architecture (trampolines) or handling.info:eu-repo/semantics/publishe

Objective vs. Subjective Evaluation of Cognitive Performance During 0.4-MPa Dives Breathing Air or Nitrox.

Divers try to limit risks associated with their sport, for instance by breathing enriched air nitrox (EANx) instead of air. This double blinded, randomized trial was designed to see if the use of EANx could effectively improve cognitive performance while diving.info:eu-repo/semantics/publishe