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Sample records for 14-d saturation dive

  1. Nutritional Assessment During a 14-d Saturation Dive: the NASA Extreme Environment Mission Operation V Project

    NASA Technical Reports Server (NTRS)

    Smith, S. M.; Davis-Street, J. E.; Fesperman, J. V.; Smith, M. D.; Rice, B. L.; Zwart, S. R.

    2006-01-01

    Ground-based analogs of spaceflight are an important means of studying physiological and nutritional changes associated with space travel, particularly since exploration missions are anticipated, and flight research opportunities are limited. A clinical nutritional assessment of the NASA Extreme Environment Mission Operation V (NEEMO) crew (4 M, 2 F) was conducted before, during, and after the 14-d saturation dive. Blood and urine samples were collected before (D-12 and D-1), during (MD 7 and MD 12), and after (R + 0 and R + 7) the dive. The foods were typical of the spaceflight food system. A number of physiological changes were reported both during the dive and post dive that are also commonly observed during spaceflight. Serum hemoglobin and hematocrit were decreased (P less than 0.05) post dive. Serum ferritin and ceruloplasmin significantly increased during the dive, while transferring receptors tended to go down during the dive and were significantly decreased by the last day (R + 0). Along with significant hematological changes, there was also evidence for increased oxidative damage and stress during the dive. 8-hydroxydeoxyguanosine was elevated (P less than 0.05) during the dive, while glutathione peroxidase and superoxide disrnutase activities were decreased (P less than 0.05) during the dive. Serum C-reactive protein (CRP) concentration also tended to increase during the dive, suggesting the presence of a stress-induced inflammatory response, Decreased leptin during the dive (P less than 0.05) may also be related to the increased stress. Similar to what is observed during spaceflight, subjects had decreased energy intake and weight loss during the dive. Together, these similarities to spaceflight provide a model to further define the physiological effects of spaceflight and investigate potential countermeasures.

  2. Neuropsychologic effects of saturation diving.

    PubMed

    Vaernes, R J; Kløve, H; Ellertsen, B

    1989-05-01

    Neuropsychologic status of saturation divers was assessed before and after 300-500 msw dives (deep saturation diving--DSD group) and before and after 3.5 yr of ordinary saturation diving (saturation diving--SD group). Average baseline results showed the divers to be slightly superior to nondiving controls. Mild-to-moderate neuropsychologic changes (greater than 10% impairment) were found in measures of tremor, spatial memory, vigilance, and automatic reactivity in 20% of the divers after deep dives (DSD group). One year postdive no recovery was observed except for a vigilance test. In the SD group, 20% of the divers showed greater than 10% impairment after 3.5 yr of ordinary saturation diving. Significant reduction in autonomic reactivity was also found and there was a relationship between low autonomic reactivity before saturation diving and number of greater than 10% impairments. For the whole group (DSD + SD divers), negative correlations were found between saturation experience and results on memory and complex visuomotor tests. Years of diving from first to last examination was positively correlated with number of greater than 10% impairments and with reduction in autonomic reactivity. No similar correlations were found to dive variables after about 3 yr of air diving. The mild-to-moderate changes seen in some divers, therefore, seem to be the effects of saturation diving. Since one deep dive may cause an effect similar to the effect of 3.5 yr of ordinary saturation diving, there is reason to believe that repeated deep diving may lead to more pronounced neuropsychologic impairment.

  3. Saturation diving; physiology and pathophysiology.

    PubMed

    Brubakk, Alf O; Ross, John A S; Thom, Stephen R

    2014-07-01

    In saturation diving, divers stay under pressure until most of their tissues are saturated with breathing gas. Divers spend a long time in isolation exposed to increased partial pressure of oxygen, potentially toxic gases, bacteria, and bubble formation during decompression combined with shift work and long periods of relative inactivity. Hyperoxia may lead to the production of reactive oxygen species (ROS) that interact with cell structures, causing damage to proteins, lipids, and nucleic acid. Vascular gas-bubble formation and hyperoxia may lead to dysfunction of the endothelium. The antioxidant status of the diver is an important mechanism in the protection against injury and is influenced both by diet and genetic factors. The factors mentioned above may lead to production of heat shock proteins (HSP) that also may have a negative effect on endothelial function. On the other hand, there is a great deal of evidence that HSPs may also have a "conditioning" effect, thus protecting against injury. As people age, their ability to produce antioxidants decreases. We do not currently know the capacity for antioxidant defense, but it is reasonable to assume that it has a limit. Many studies have linked ROS to disease states such as cancer, insulin resistance, diabetes mellitus, cardiovascular diseases, and atherosclerosis as well as to old age. However, ROS are also involved in a number of protective mechanisms, for instance immune defense, antibacterial action, vascular tone, and signal transduction. Low-grade oxidative stress can increase antioxidant production. While under pressure, divers change depth frequently. After such changes and at the end of the dive, divers must follow procedures to decompress safely. Decompression sickness (DCS) used to be one of the major causes of injury in saturation diving. Improved decompression procedures have significantly reduced the number of reported incidents; however, data indicate considerable underreporting of injuries

  4. Saturation diving; physiology and pathophysiology.

    PubMed

    Brubakk, Alf O; Ross, John A S; Thom, Stephen R

    2014-07-01

    In saturation diving, divers stay under pressure until most of their tissues are saturated with breathing gas. Divers spend a long time in isolation exposed to increased partial pressure of oxygen, potentially toxic gases, bacteria, and bubble formation during decompression combined with shift work and long periods of relative inactivity. Hyperoxia may lead to the production of reactive oxygen species (ROS) that interact with cell structures, causing damage to proteins, lipids, and nucleic acid. Vascular gas-bubble formation and hyperoxia may lead to dysfunction of the endothelium. The antioxidant status of the diver is an important mechanism in the protection against injury and is influenced both by diet and genetic factors. The factors mentioned above may lead to production of heat shock proteins (HSP) that also may have a negative effect on endothelial function. On the other hand, there is a great deal of evidence that HSPs may also have a "conditioning" effect, thus protecting against injury. As people age, their ability to produce antioxidants decreases. We do not currently know the capacity for antioxidant defense, but it is reasonable to assume that it has a limit. Many studies have linked ROS to disease states such as cancer, insulin resistance, diabetes mellitus, cardiovascular diseases, and atherosclerosis as well as to old age. However, ROS are also involved in a number of protective mechanisms, for instance immune defense, antibacterial action, vascular tone, and signal transduction. Low-grade oxidative stress can increase antioxidant production. While under pressure, divers change depth frequently. After such changes and at the end of the dive, divers must follow procedures to decompress safely. Decompression sickness (DCS) used to be one of the major causes of injury in saturation diving. Improved decompression procedures have significantly reduced the number of reported incidents; however, data indicate considerable underreporting of injuries

  5. Nutritional status changes in humans during a 14-day saturation dive: the NASA Extreme Environment Mission Operations V project.

    PubMed

    Smith, Scott M; Davis-Street, Janis E; Fesperman, J Vernell; Smith, Myra D; Rice, Barbara L; Zwart, Sara R

    2004-07-01

    Ground-based analogs of spaceflight are an important means of studying physiologic and nutritional changes associated with space travel, and the NASA Extreme Environment Mission Operations V (NEEMO) is such an analog. To determine whether saturation diving has nutrition-related effects similar to those of spaceflight, we conducted a clinical nutritional assessment of the NEEMO crew (4 men, 2 women) before, during, and after their 14-d saturation dive. Blood and urine samples were collected before, during, and after the dive. The foods consumed by the crew were typical of the spaceflight food system. A number of physiologic changes were observed, during and after the dive, that are also commonly observed during spaceflight. Hemoglobin and hematocrit were lower (P < 0.05) after the dive. Transferrin receptors were significantly lower immediately after the dive. Serum ferritin increased significantly during the dive. There was also evidence indicating that oxidative damage and stress increased during the dive. Glutathione peroxidase and superoxide dismutase decreased during and after the dive (P < 0.05). Decreased leptin during the dive (P < 0.05) may have been related to the increased stress. Subjects had decreased energy intake and weight loss during the dive, similar to what is observed during spaceflight. Together, these similarities to spaceflight provide a model to use in further defining the physiologic effects of spaceflight and investigating potential countermeasures.

  6. Nutritional status changes in humans during a 14-day saturation dive: the NASA Extreme Environment Mission Operations V project

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Davis-Street, Janis E.; Fesperman, J. Vernell; Smith, Myra D.; Rice, Barbara L.; Zwart, Sara R.

    2004-01-01

    Ground-based analogs of spaceflight are an important means of studying physiologic and nutritional changes associated with space travel, and the NASA Extreme Environment Mission Operations V (NEEMO) is such an analog. To determine whether saturation diving has nutrition-related effects similar to those of spaceflight, we conducted a clinical nutritional assessment of the NEEMO crew (4 men, 2 women) before, during, and after their 14-d saturation dive. Blood and urine samples were collected before, during, and after the dive. The foods consumed by the crew were typical of the spaceflight food system. A number of physiologic changes were observed, during and after the dive, that are also commonly observed during spaceflight. Hemoglobin and hematocrit were lower (P < 0.05) after the dive. Transferrin receptors were significantly lower immediately after the dive. Serum ferritin increased significantly during the dive. There was also evidence indicating that oxidative damage and stress increased during the dive. Glutathione peroxidase and superoxide dismutase decreased during and after the dive (P < 0.05). Decreased leptin during the dive (P < 0.05) may have been related to the increased stress. Subjects had decreased energy intake and weight loss during the dive, similar to what is observed during spaceflight. Together, these similarities to spaceflight provide a model to use in further defining the physiologic effects of spaceflight and investigating potential countermeasures.

  7. Nutritional status changes in humans during a 14-day saturation dive: the NASA Extreme Environment Mission Operations V project.

    PubMed

    Smith, Scott M; Davis-Street, Janis E; Fesperman, J Vernell; Smith, Myra D; Rice, Barbara L; Zwart, Sara R

    2004-07-01

    Ground-based analogs of spaceflight are an important means of studying physiologic and nutritional changes associated with space travel, and the NASA Extreme Environment Mission Operations V (NEEMO) is such an analog. To determine whether saturation diving has nutrition-related effects similar to those of spaceflight, we conducted a clinical nutritional assessment of the NEEMO crew (4 men, 2 women) before, during, and after their 14-d saturation dive. Blood and urine samples were collected before, during, and after the dive. The foods consumed by the crew were typical of the spaceflight food system. A number of physiologic changes were observed, during and after the dive, that are also commonly observed during spaceflight. Hemoglobin and hematocrit were lower (P < 0.05) after the dive. Transferrin receptors were significantly lower immediately after the dive. Serum ferritin increased significantly during the dive. There was also evidence indicating that oxidative damage and stress increased during the dive. Glutathione peroxidase and superoxide dismutase decreased during and after the dive (P < 0.05). Decreased leptin during the dive (P < 0.05) may have been related to the increased stress. Subjects had decreased energy intake and weight loss during the dive, similar to what is observed during spaceflight. Together, these similarities to spaceflight provide a model to use in further defining the physiologic effects of spaceflight and investigating potential countermeasures. PMID:15226467

  8. Mechanisms of reduced pulmonary function after a saturation dive.

    PubMed

    Thorsen, E; Segadal, K; Kambestad, B K

    1994-01-01

    Deep saturation diving has been shown to have prolonged effects on pulmonary function. We wanted to assess the relative contribution of various factors that could contribute to these effects. Pulmonary function was, therefore, measured before and after 17 different saturation diving operations to depths of 5-450 m of sea water, corresponding to absolute pressures of 0.15-4.6 MPa. Four to fifteen divers participated in each operation. The measurements included static and dynamic lung volumes and flows, transfer factor of the lungs for carbon monoxide (TLCO), and closing volume. The dives were characterized by the cumulative hyperoxic and hyperbaric exposures, and the load of venous gas microemboli encountered during decompression was measured in 41 divers in three dives to 0.25, 1.2 and 3.7 MPa. TLCO was reduced by 8.3 +/- 7.0% mean +/- SD after the dives, this correlated with cumulative hyperoxic exposure and load of venous gas microembolism, independently of each other. Closing volume was increased and forced mid-expiratory flow rate reduced, in correlation with cumulative hyperoxic exposure. An increase in total lung capacity correlated with cumulative hyperbaric exposure. We conclude that hyperoxia, hyperbaria, and venous gas microembolism all contribute to the changes in pulmonary function after a single saturation dive, and all may explain some of the long-term effects of diving on pulmonary function.

  9. Impact of a deep saturation dive on semen quality.

    PubMed

    Aitken, R J; Buckingham, D; Richardson, D; Gardiner, J C; Irvine, D S

    2000-04-01

    The demonstration dive 'Aurora' has provided an opportunity to study the impact of extreme hyperbaric conditions on male fertility. This operation involved a 33-day diving programme during which divers were exposed to a maximum pressure of 4.6 Mega Pascals (Mpa) for 7 days. At days - 4, + 27, + 34, + 82 and + 263 relative to the initiation of the dive, semen samples were analysed to determine the quality of spermatogenesis and the functional competence of the spermatozoa. A dramatic fall in semen quality was observed in association with the dive and by day + 82 the potential fertility of the men was seriously compromised as evidenced by oligoasthenoteratozoospermic semen profiles and the poor fertilizing potential of the spermatozoa. These studies indicate, for the first time, that the severe hyperbaric conditions associated with deep saturation dives have a profound effect on male reproductive function.

  10. Psychometric evaluation of divers performing a series of heliox non-saturation dives.

    PubMed

    Hodgson, M; Golding, J F

    1991-05-01

    Psychometric performance of 12 divers was evaluated throughout a series of 60-72-m in-water heliox non-saturation ('bounce') dives using a repeated-measures, within-subject design. Assessments were made onboard a dive tender, using a portable computerized battery within 30 min of the diver leaving the water, 2 h later, and on rest days. No significant decrement in performance was demonstrated either post-dive or throughout the series. Ten controls showed no alteration in performance due to environmental factors such as ship motion. The consistency of the results confirmed the suitability of this system for monitoring cognitive function during a series of potentially hazardous dives.

  11. Effects of a single saturation dive on lung function and exercise performance.

    PubMed

    Lehnigk, B; Jörres, R A; Elliott, D H; Holthaus, J; Magnussen, H

    1997-01-01

    We studied the effects of an experimental saturation dive to 360 and 450 m in a simulation chamber on spirometric lung function, diffusing capacity, pulmonary compliance, and exercise performance in eight professional divers (age 22-40 years). To assess intraindividual variability, all parameters were measured on 2 days before and on 2 consecutive days immediately after the dive. For the group as a whole there was a significant increase in vital capacity and alveolar volume, and a decrease in Krogh factor and specific compliance (P < 0.01). These changes were reduced on the 2nd day after the dive. All subjects showed lowered exercise performance after the dive. Arterial pressure of oxygen and ventilation during exercise increased (P < 0.01), whereas arterial pressure of carbon dioxide, oxygen uptake, and anaerobic threshold decreased (P < 0.01). Exercise parameters showed only a slight trend towards pre-dive values on the 2nd day after a dive. The individual analysis revealed that after the dive two subjects showed a marked decrease in diffusing capacity and a more than average decrease in Krogh factor (TLCO/VA). One of them had signs of mild decompression sickness and the other, signs of pre-existing obstructive airways disease. Our data are compatible with the hypothesis that the effects of a single deep saturation dive on pulmonary function and exercise performance are the results of counteracting mechanisms. We suggest that lung volumes increase due to the enhanced work of breathing during a deep saturation dive and that these changes could mask an impairment in gas exchange. Furthermore, a saturation dive can induce an apparent deterioration of pulmonary function.

  12. Supplementation of antioxidants prevents oxidative stress during a deep saturation dive.

    PubMed

    Ikeda, Makoto; Nakabayashi, Kazuhiko; Shinkai, Masaharu; Hara, Yukihiko; Kizaki, Takako; Oh-ishi, Shuji; Ohno, Hideki

    2004-08-01

    Conflicting views exist at the present regarding the influences of a deep saturation dive on liver function in divers. Therefore, we first reevaluated whether a deep saturation dive (400 msw) induces a hepatic disturbance. As the result, plasma activities of both transaminases (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) increased significantly, whereas cholinesterase (Ch-E) activity decreased markedly, being highly suggestive of liver dysfunction. Assuming that the liver dysfunction was attributable to oxidative stress, we next examined the effects of supplementation of antioxidants (600 mg of vitamin C, 150 mg of alpha-tocopherol, and 600 mg of tea catechins per day) on liver function in saturation divers. As was anticipated, the antioxidants taken appeared to prevent a hepatic disturbance, indicating that a deep saturation dive provokes liver dysfunction probably due to oxidative stress. Thus, we recommend that saturation divers should take supplements of antioxidants.

  13. Decompression from a deep nitrogen/oxygen saturation dive--a case report.

    PubMed

    Barry, P D; Vann, R D; Youngblood, D A; Peterson, R E; Bennett, P B

    1984-12-01

    Ten divers participated in a 4.5 d nitrogen/oxygen saturation dive to 165 fsw. There were daily 2 h excursions to 61 msw (200 fsw). The divers breathed air during the excursions and 0.51 bar (0.5 atm) oxygen in nitrogen at 50.3 msw (165 fsw). The final decompression began 6 h after the last excursion. The oxygen partial pressure was 0.51 bar (0.5 atm) from 50.3 to 13.7 msw (165 to 45 fsw), and air was used from 13.7 msw (45 fsw) to the surface. By 6.1 msw (20 fsw), four divers had developed decompression sickness. A fifth diver developed decompression sickness during a commercial air flight 68 h after surfacing. Comparison of ascent rates for this dive and for air or nitrogen/oxygen saturation dives reported in the literature suggests that deeper dives require slower rates of ascent. Dives shallower than 30.5 msw (100 fsw) had a mean ascent rate of 1 msw/h (3.2 fsw/h) and 14 decompression incidents in 107 man-exposures. Dives deeper than 30.5 msw (100 fsw) had a mean rate of 0.76 msw/h (2.5 fsw/h) and 14 incidents in 45 man-exposures.

  14. Mental abilities and performance efficacy under a simulated 480-m helium-oxygen saturation diving.

    PubMed

    Hou, Gonglin; Zhang, Youlan; Zhao, Na; Chen, Ruiyong; Xiao, Weibing; Yu, Hao; Wang, Jiachun; Yuan, Ti-Fei

    2015-01-01

    Stress in extreme environment severely disrupts human physiology and mental abilities. The present study investigated the cognition and performance efficacy of four divers during a simulated 480 meters helium-oxygen saturation diving. We analyzed the spatial memory, 2D/3D mental rotation functioning, grip strength, and hand-eye coordination ability in four divers during the 0-480 m compression and decompression processes of the simulated diving. The results showed that except for its mild decrease on grip strength, the high atmosphere pressure condition significantly impaired the hand-eye coordination (especially above 300 m), the reaction time and correct rate of mental rotation, as well as the spatial memory (especially as 410 m), showing high individual variability. We conclude that the human cognition and performance efficacy are significantly affected during deep water saturation diving.

  15. Pulmonary function one and four years after a deep saturation dive.

    PubMed

    Thorsen, E; Segadal, K; Kambestad, B K; Gulsvik, A

    1993-04-01

    The pulmonary function of 24 Norwegian divers who had participated in a deep saturation dive to pressures of 3.1-4.6 MPa was reevaluated one and four years later. Twenty-eight divers performing ordinary saturation diving to pressures of 0.8-1.6 MPa and followed over a three-year period served as referents. A significant reduction in forced expiratory volume in 1 s (FEV1.0) of 210 (SD 84) ml (P < 0.001) occurred the first year after the dive. Thereafter the annual reduction in FEV1.0 was 28 (SD 62) ml.year-1; this value did not differ from the 35 (SD 80) ml.year-1 of the referents. The forced midexpiratory flow rate and forced expiratory flow rates at low lung volumes were also significantly reduced one year after the deep dive, and the closing volume was increased. No significant changes occurred in forced vital capacity. The results agree with those of cross-sectional studies on divers' lung function and indicate the development of airflow limitation in relation to diving exposure.

  16. Saturation diving alters folate status and biomarkers of DNA damage and repair.

    PubMed

    Zwart, Sara R; Jessup, J Milburn; Ji, Jiuping; Smith, Scott M

    2012-01-01

    Exposure to oxygen-rich environments can lead to oxidative damage, increased body iron stores, and changes in status of some vitamins, including folate. Assessing the type of oxidative damage in these environments and determining its relationships with changes in folate status are important for defining nutrient requirements and designing countermeasures to mitigate these effects. Responses of humans to oxidative stressors were examined in participants undergoing a saturation dive in an environment with increased partial pressure of oxygen, a NASA Extreme Environment Mission Operations mission. Six participants completed a 13-d saturation dive in a habitat 19 m below the ocean surface near Key Largo, FL. Fasting blood samples were collected before, twice during, and twice after the dive and analyzed for biochemical markers of iron status, oxidative damage, and vitamin status. Body iron stores and ferritin increased during the dive (P<0.001), with a concomitant decrease in RBC folate (P<0.001) and superoxide dismutase activity (P<0.001). Folate status was correlated with serum ferritin (Pearson r = -0.34, P<0.05). Peripheral blood mononuclear cell poly(ADP-ribose) increased during the dive and the increase was significant by the end of the dive (P<0.001); γ-H2AX did not change during the mission. Together, the data provide evidence that when body iron stores were elevated in a hyperoxic environment, a DNA damage repair response occurred in peripheral blood mononuclear cells, but double-stranded DNA damage did not. In addition, folate status decreases quickly in this environment, and this study provides evidence that folate requirements may be greater when body iron stores and DNA damage repair responses are elevated.

  17. Oxygen saturation in free-diving whales: optical sensor development

    NASA Astrophysics Data System (ADS)

    Gutierrez-Herrera, Enoch; Vacas-Jacques, Paulino; Anderson, Rox; Zapol, Warren; Franco, Walfre

    2013-02-01

    Mass stranding of live whales has been explained by proposing many natural or human-related causes. Recent necropsy reports suggest a link between the mass stranding of beaked whales and the use of naval mid-frequency sonar. Surprisingly, whales have experienced symptoms similar to those caused by inert gas bubbles in human divers. Our goal is to develop a compact optical sensor to monitor the consumption of the oxygen stores in the muscle of freely diving whales. To this end we have proposed the use of a near-infrared phase-modulated frequency-domain spectrophotometer, in reflectance mode, to probe tissue oxygenation. Our probe consists of three main components: radiofrequency (RF) modulated light sources, a high-bandwidth avalanche photodiode with transimpedance amplifier, and a RF gain and phase detector. In this work, we concentrate on the design and performance of the light sensor, and its corresponding amplifier unit. We compare three state-of-the-art avalanche photodiodes: one through-hole device and two surface-mount detectors. We demonstrate that the gain due to the avalanche effect differs between sensors. The avalanche gain near maximum bias of the through-hole device exceeds by a factor of 2.5 and 8.3 that of the surface-mount detectors. We present the behavior of our assembled through-hole detector plus high-bandwidth transimpedance amplifier, and compare its performance to that of a commercially available module. The assembled unit enables variable gain, its phase noise is qualitatively lower, and the form factor is significantly smaller. Having a detecting unit that is compact, flexible, and functional is a milestone in the development of our tissue oxygenation tag.

  18. Effects of deep saturation diving on the lymphocyte subsets of healthy divers.

    PubMed

    Shinomiya, N; Suzuki, S; Hashimoto, A; Oiwa, H

    1994-09-01

    We examined the effect of deep saturation diving on the host defense mechanisms of five healthy volunteers using fluorescein-dye-conjugated monoclonal antibodies. Six divers engaged in a 440-m saturation diving simulation with total hyperbaric exposure of 30 days; five served as subjects. Change in the expression of surface molecules on the lymphocytes was analyzed during that period. Blood samples were serially taken on Days 4, 6, 8, 15, 22, 29, and after surfacing. The total number of lymphocytes showed no remarkable change. However, the fraction of T (CD3+) cells decreased from 68.0 +/- 3.3% to 55.8 +/- 5.8% (Day 8), and B cells increased reciprocally. In these T cells, the CD4:CD8 ratio (normally > 1.0) became less than 1.0 during compression and thereafter. In spite of the prophylactic use of anti-external otitis agents, one of the divers revealed a remarkable growth of Pseudomonas in the external auditory meatus, showing a high level of blood endotoxin (10.2 pg/ml). These results suggest that decrease in CD4+ fraction of T lymphocytes might explain in part the decreased resistance of divers to infective microorganisms in deep saturation diving.

  19. Acute otitis externa in divers working in the North Sea: a microbiological survey of seven saturation dives.

    PubMed Central

    Alcock, S. R.

    1977-01-01

    Saturation diving is an important and widely used technique in the Offshore Oil Industry. During 1974-5 two saturation dives in the North Sea were terminated because of outbreaks of incapacitating otitis externa, and others were disrupted. Pseudomonas aeruginosa was consistently isolated from the ears of affected divers. Because complex work schedules were threatened seven subsequent dives were subjected to microbiological monitoring and control. Colonization of ear canal with P. aeruginosa or with other gram-negative bacilli occurred in 39 (67%) of the 58 divers studied, usually within 7 days of starting the dive. Data obtained by serotyping this isolations of P. aeruginosa suggested that a single infected diver may be the source of organisms which rapidly spread to his colleagues and throughout the living chambers, that the living chambers may constitute a reservoir of infection during and between dives, and that certain serotypes of P. aeruginosa are more likely than others to colonize the ear canal in the conditions of a saturation dive. The control measures used during the dives were only partially effective, but none of the divers suffered severe pain and all the dives were an operational success. PMID:405421

  20. Development of prototype full-automatic environmental control system for nitrox saturation diving.

    PubMed

    Okamoto, M; Yamagichi, H

    1998-01-01

    A full-automated hyperbaric environmental control system (HECS) for nitrox saturation diving HABITAT has been examined since 1994. HECS was planned to be located inside HABITAT and operated automatically by supplying electricity and cooling water. To realize this, a regenerative-type carbon dioxide removal method and AC 100 V electric powered blower system were developed as key technology. By using molecular sieves as an adsorbent material for carbon dioxide, automated sequence for adsorbent and regeneration could be successfully realized. Also, by using solid-state conductor circuit, an AC 100 V type blower to use under hyperbaric conditions could be developed. A prototype HECS was manufactured and settled in JAMSTEC diving simulator for further evaluation. PMID:11876196

  1. Brainstem auditory evoked potentials during a helium-oxygen saturation dive to 450 meters of seawater.

    PubMed

    Lorenz, J; Brooke, S T; Petersen, R; Török, Z; Wenzel, J

    1995-09-01

    When divers are exposed to extreme atmospheric pressures they may exhibit symptoms of the high pressure nervous syndrome (HPNS). Although clinical HPNS symptoms are well described, little is known about the underlying pathophysiologic mechanisms. Special HPNS signs like vertigo and tremor suggested sensory-motor hyperexcitability resulting from brainstem dysfunction. We therefore studied brainstem auditory evoked potential (BAEP) repeatedly in four divers during an experimental deep helium-oxygen saturation dive to 450 meters of seawater (msw). Wave I (auditory nerve response) latency decreased whereas interpeak latencies (IPLs) I-III and I-V, which indicate respective cochleo-pontine and cochleo-mesencephalic transmission time, prolonged during the dive. IPLs III-V also prolonged the dive, but with greater variability among divers. Two divers showed a marked reversal of the normal attenuation effect of increased stimulus presentation rates on IV and V amplitudes during compression, an effect that subsided during the stay at bottom depth. This finding might indicate a relative enhancement of synaptic excitability and is presumed to be a feature of HPNS. Wave I latency reduction might at least partly be caused by accelerated sound conduction in dense helium. Additionally, an upward shift of middle ear resonance frequencies in helium can induce a basal shift of the main cochlear portion responding to the wide band clicks. This effect may reduce wave I latency due to greater relative input from the basal high frequency-short latency-cochlear neurons. Pressure-induced decrease of nerve conduction velocity, delay of synaptic transmission, and inhibitory modulation of midbrain auditory afferents possibly contributed to observed interpeak latency prolongations. Clinical HPNS signs, such as tiredness, dizziness, postural and intentional hand tremor, ataxia, and opsoclonus, were noted in three divers after reaching 300 msw and continued throughout the 37-h stay at bottom

  2. Sleep, mood, and fatigue during a 14-day He-O2 open-sea saturation dive to 850 fsw with excursions to 950 fsw.

    PubMed

    Townsend, R E; Hall, D A

    1978-06-01

    To obtain information on sleep, mood, and performance of divers and surface support personnel during deep dives in the open sea, 12 divers and 12 surface support personnel were monitored during a 14-day open-sea saturation dive using the U.S. Navy Deep Diving System, Mark 2, Mod O. Divers lived in the deck decompression chambers at 850 fsw equivalent and made 5 days of excursion wet dives to approximately 950 fsw via the Personnel Transfer Capsule. Electroencephalographic and self-report measures of sleep, and measures of mood, anxiety, and 4-choice reaction time performance were obtained during a predive base-line period and throughout the dive and decompression. Results suggested that, unless personnel are rotated, there are limitations to the practical duration of very deep open-sea saturation dives caused by the accumulation of sleep debt, fatigue, and loss of psychological vigor.

  3. Hormonal and cardiorespiratory changes following simulated saturation dives to 4 and 11 ATA.

    PubMed

    Mateev, G; Djarova, T; Ilkov, A; Sachanska, T; Klissurov, L

    1990-01-01

    Professional divers were compressed with trimix to 4 ATA (2 persons, aged 35 and 26) and to 11 ATA (3 persons, aged 34, 26, and 23) for saturation dives with durations of 48 and 50 h, followed by 33 and 109 h of decompression, respectively. Pre- and postdive cardiorespiratory reactions to a step test--heart rate (HR) and ventilation (VE)--and concentrations of growth hormone, corticotropin, cortisol, insulin, lutotropin, folitropin, triiodothyronine (T3), thyroxine (T4), thyrotropin, and testosterone in serum were studied. All divers developed postdecompression tachycardia (90-108 beats/min), which persisted 24 h after surfacing. Physical fitness assessed by steady state HR and VE during a step test was lowered 24 h after decompression compared with the predive values in 4 divers and enhanced in 1. These data provide evidence for hindered and delayed readaptation of the cardiorespiratory system to a normobaric environment. T3, T4, and testosterone were significantly decreased postdive. Hormonal responses were found to exhibit a very individual pattern from which it was possible to estimate the adaptive reactions after hyperbaric exposure. Professional divers with a lower level of physical fitness showed more pronounced hormonal responses to hyperbaric environments. PMID:2316058

  4. No changes in lung function after a saturation dive to 2.5 MPa with intermittent reduction in Po2 during decompression.

    PubMed

    Thorsen, E; Segadal, K; Stuhr, L E B; Troland, K; Grønning, M; Marstein, S; Hope, A

    2006-10-01

    Decompression stress and exposure to hyperoxia may cause a reduction in transfer factor of the lung for carbon monoxide and in maximal aerobic capacity after deep saturation dives. In this study lung function and exercise capacity were assessed before and after a helium-oxygen saturation dive to a pressure of 2.5 MPa where the decompression rate was reduced compared with previous deep dives, and the hyperoxic exposure was reduced by administering oxygen intermittently at pressures of 50 and 30 kPa during decompression. Eight experienced divers of median age 41 years (range 29-48) participated in the dive. The incidence of venous gas microemboli was low compared with previous deep dives. Except for one subject having treatment for decompression sickness, no changes in lung function or angiotensin converting enzyme, a marker of pulmonary endothelial cell damage, were demonstrated. The modified diving procedures with respect to decompression rate and hyperoxic exposure may have contributed to the lack of changes in lung function in this dive compared with previous deep saturation dives.

  5. Potential Fifty Percent Reduction in Saturation Diving Decompression Time Using a Combination of Intermittent Recompression and Exercise

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael I.; Abercromby, Andrew; Conklin, Johnny

    2007-01-01

    Conventional saturation decompression protocols use linear decompression rates that become progressively slower at shallower depths, consistent with free gas phase control vs. dissolved gas elimination kinetics. If decompression is limited by control of free gas phase, linear decompression is an inefficient strategy. The NASA prebreathe reduction program demonstrated that exercise during O2 prebreathe resulted in a 50% reduction (2 h vs. 4 h) in the saturation decompression time from 14.7 to 4.3 psi and a significant reduction in decompression sickness (DCS: 0 vs. 23.7%). Combining exercise with intermittent recompression, which controls gas phase growth and eliminates supersaturation before exercising, may enable more efficient saturation decompression schedules. A tissue bubble dynamics model (TBDM) was used in conjunction with a NASA exercise prebreathe model (NEPM) that relates tissue inert gas exchange rate constants to exercise (ml O2/kg-min), to develop a schedule for decompression from helium saturation at 400 fsw. The models provide significant prediction (p < 0.001) and goodness of fit with 430 cases of DCS in 6437 laboratory dives for TBDM (p = 0.77) and with 22 cases of DCS in 159 altitude exposures for NEPM (p = 0.70). The models have also been used operationally in over 25,000 dives (TBDM) and 40 spacewalks (NEPM). The standard U.S. Navy (USN) linear saturation decompression schedule from saturation at 400 fsw required 114.5 h with a maximum Bubble Growth Index (BGI(sub max)) of 17.5. Decompression using intermittent recompression combined with two 10 min exercise periods (75% VO2 (sub peak)) per day required 54.25 h (BGI(sub max): 14.7). Combined intermittent recompression and exercise resulted in a theoretical 53% (2.5 day) reduction in decompression time and theoretically lower DCS risk compared to the standard USN decompression schedule. These results warrant future decompression trials to evaluate the efficacy of this approach.

  6. Hana kai ii: a 17-day dry saturation dive at 18.6 ATA. II. Energy balance.

    PubMed

    Webb, P; Troutman, S J; Frattali, V; Dressendorfer, R H; Dwyer, J; Moore, T O; Morlock, J F; Smith, R M; Ohta, Y; Hong, S K

    1977-09-01

    Since previous saturation dives have caused loss of body weight despite apparently adequate-to-high food intake, a complete study of energy balance was undertaken during the saturation dive Hana Kai II. Over a 30-day period in the hyperbaric chamber (3 days of predive control, 1 day of compression, 16 days at 18.6 ATA, 7 days of decompression, and 3 days of postdive control), all food, urine, and feces for five men were analyzed by bomb calorimetry; 24-h energy expenditure (M) was measured from continuous VO2, VCO2, and urine N. Body weight was taken daily; body composition was assessed from density, total body water, and skinfold thickness. Food intake was high throughout the 30 days (about 3500 kcal/day) while fecal and urinary losses were a normal 6-8% of intake. Energy expenditure was increased a little by the hyperbaric condition, but averaged only 2431 kcal/day for the 30 days and yet there was an average loss of adipose tissue of 0.8 kg for each man for the entire period. Nitrogen balance was positive. There was no evidence of heat gain or loss. The energy balance, total fuel compared with energy expenditure, required an additional 919 kcal/man-day for 30 days, an unidentified term which is not measured by conventional techniques. PMID:910315

  7. Up-Regulation of Antioxidant Proteins in the Plasma Proteome during Saturation Diving: Unique Coincidence under Hypobaric Hypoxia

    PubMed Central

    Domoto, Hideharu; Iwaya, Keiichi; Ikomi, Fumitaka; Matsuo, Hirotaka; Tadano, Yutaka; Fujii, Shigenori; Tachi, Kazuyoshi; Itoh, Yoshiyuki; Sato, Michiya; Inoue, Kimitoshi; Shinomiya, Nariyoshi

    2016-01-01

    Saturation diving (SD) is one of the safest techniques for tolerating hyperbaric conditions for long durations. However, the changes in the human plasma protein profile that occur during SD are unknown. To identify differential protein expression during or after SD, 65 blood samples from 15 healthy Japanese men trained in SD were analyzed by two-dimensional fluorescence difference gel electrophoresis. The expression of two proteins, one 32.4 kDa with an isoelectric point (pI) of 5.8 and the other 44.8 kDa with pI 4.0, were elevated during SD to 60, 100, and 200 meters sea water (msw). The expression of these proteins returned to pre-diving level when the SD training was completed. The two proteins were identified using in-gel digestion and mass spectrometric analysis; the 32.4 kDa protein was transthyretin and the 44.8 kDa protein was alpha-1-acid glycoprotein 1. Oxidation was detected at methionine 13 of transthyretin and at methionine 129 of alpha-1-acid glycoprotein 1 by tandem mass spectrometry. Moreover, haptoglobin was up-regulated during the decompression phase of 200 msw. These plasma proteins up-regulated during SD have a common function as anti-oxidants. This suggests that by coordinating their biological effects, these proteins activate a defense mechanism to counteract the effects of hyperbaric-hyperoxic conditions during SD. PMID:27741252

  8. Effect of a short-acting NO donor on bubble formation from a saturation dive in pigs.

    PubMed

    Møllerløkken, A; Berge, V J; Jørgensen, A; Wisløff, U; Brubakk, A O

    2006-12-01

    It has previously been reported that a nitric oxide (NO) donor reduces bubble formation from an air dive and that blocking NO production increases bubble formation. The present study was initiated to see whether a short-acting NO donor (glycerol trinitrate, 5 mg/ml; Nycomed Pharma) given immediately before start of decompression would affect the amount of vascular bubbles during and after decompression from a saturation dive in pigs. A total of 14 pigs (Sus scrofa domestica of the strain Norsk landsvin) were randomly divided into an experimental (n = 7) and a control group (n = 7). The pigs were anesthetized with ketamine and alpha-chloralose and compressed in a hyperbaric chamber to 500 kPa (40 m of seawater) in 2 min, and they had 3-h bottom time while breathing nitrox (35 kPa O(2)). The pigs were all decompressed to the surface (100 kPa) at a rate of 200 kPa/h. During decompression, the inspired Po(2) of the breathing gas was kept at 100 kPa. Thirty minutes before decompression, the experimental group received a short-acting NO donor intravenously, while the control group were given equal amounts of saline. The average number of bubbles seen during the observation period decreased from 0.2 to 0.02 bubbles/cm(2) (P < 0.0001) in the experimental group compared with the controls. The present study gives further support to the role of NO in preventing vascular bubble formation after decompression.

  9. Doppler ultrasound surveillance in deep tunneling compressed-air work with Trimix breathing: bounce dive technique compared to saturation-excursion technique.

    PubMed

    Vellinga, T P van Rees; Sterk, W; de Boer, A G E M; van der Beek, A J; Verhoeven, A C; van Dijk, F J H

    2008-01-01

    The Western Scheldt Tunneling Project in The Netherlands provided a unique opportunity to evaluate two deep-diving techniques with Doppler ultrasound surveillance. Divers used the bounce diving techniques for repair and maintenance of the TBM. The tunnel boring machine jammed at its deepest depth. As a result the work time was not sufficient. The saturation diving technique was developed and permitted longer work time at great depth. Thirty-one divers were involved in this project. Twenty-three divers were examined using Doppler ultrasound. Data analysis addressed 52 exposures to Trimix at 4.6-4.8 bar gauge using the bounce technique and 354 exposures to Trimix at 4.0-6.9 bar gauge on saturation excursions. No decompression incidents occurred with either technique during the described phase of the project. Doppler ultrasound revealed that the bubble loads assessed in both techniques were generally low. We find out, that despite longer working hours, shorter decompression times and larger physical workloads, the saturation-excursion technique was associated with significant lower bubble grades than in the bounce technique using Doppler Ultrasound. We conclude that the saturation-excursion technique with Trimix is a good option for deep and long exposures in caisson work. The Doppler technique proved valuable, and it should be incorporated in future compressed-air work. PMID:19175196

  10. Doppler ultrasound surveillance in deep tunneling compressed-air work with Trimix breathing: bounce dive technique compared to saturation-excursion technique.

    PubMed

    Vellinga, T P van Rees; Sterk, W; de Boer, A G E M; van der Beek, A J; Verhoeven, A C; van Dijk, F J H

    2008-01-01

    The Western Scheldt Tunneling Project in The Netherlands provided a unique opportunity to evaluate two deep-diving techniques with Doppler ultrasound surveillance. Divers used the bounce diving techniques for repair and maintenance of the TBM. The tunnel boring machine jammed at its deepest depth. As a result the work time was not sufficient. The saturation diving technique was developed and permitted longer work time at great depth. Thirty-one divers were involved in this project. Twenty-three divers were examined using Doppler ultrasound. Data analysis addressed 52 exposures to Trimix at 4.6-4.8 bar gauge using the bounce technique and 354 exposures to Trimix at 4.0-6.9 bar gauge on saturation excursions. No decompression incidents occurred with either technique during the described phase of the project. Doppler ultrasound revealed that the bubble loads assessed in both techniques were generally low. We find out, that despite longer working hours, shorter decompression times and larger physical workloads, the saturation-excursion technique was associated with significant lower bubble grades than in the bounce technique using Doppler Ultrasound. We conclude that the saturation-excursion technique with Trimix is a good option for deep and long exposures in caisson work. The Doppler technique proved valuable, and it should be incorporated in future compressed-air work.

  11. Effect of mental task load on fronto-central theta activity in a deep saturation dive to 450 msw.

    PubMed

    Lorenz, J; Lorenz, B; Heineke, M

    1992-07-01

    The increase of theta activity (4-7 Hz) in the electroencephalogram (EEG) during deep diving is commonly attributed to pathophysiologic mechanisms underlying the high pressure neurologic syndrome. The aim of this study was to clarify whether more precise cognitive aspects of the condition may be described in which theta activity occurs during a deep dive. Among 4 divers who were repeatedly examined during the GUSI 14 dive to 450 msw, 3 divers exhibited a pronounced correlation between short-term memory load, as varied by the memory set size of Sternberg's memory search task (MST), and the size of a distinct peak in the theta band of the EEG-power spectrum. The power of this peak was greatest in the fronto-central electrode position (Fz), increased dramatically during MST-performance at pressure, and failed to subside fully 1 day before surfacing. Despite the close dependency of observed theta activity on cognitive demands, no consistent correlation with performance measures (mean reaction time and errors) was found. In one diver, theta waves of similar morphology appeared in the resting EEG and increased significantly during the dive. We suggest two alternative explanations for the positive interaction of memory load and hyperbaric exposure on Fz-theta: a) Both factors induce a state of increased mental effort or selectivity of attention, known to be accompanied by frontal theta activity from normobaric studies. b) Pressure abnormally facilitates or patterns rhythmical excitations underlying theta activity that would occur naturally to a lesser extent during certain mental activities, learning, or repetitive short-term memory operations.

  12. Saturation diving with heliox to 350 meters. Observation on hearing threshold, brainstem evoked response and acoustic impedance.

    PubMed

    Wang, L; Jiang, W; Gong, J H; Zheng, X Y

    1994-12-01

    Four divers were compressed to 350 m to observe changes in hearing threshold, brainstem evoked response and acoustic impedance. The divers experienced no tinnitus, impairment of hearing, earache during compression. Examination showed that the threshold of lower frequency range of hearing was elevated because of the masking effect of the noise in the hyperbaric chamber. Changes in waveform and latency of brainstem evoked response were due to changes in sound wave transmission affected by the chamber pressure and a poor ratio of signal to noise in the hyperbaric environment with heliox. All these changes were transient. After leaving the chamber, the hearing threshold and brainstem evoked response returned to normal. Besides, there were no changes in tympanogram, acoustic compliance and stapedius reflex before and after diving. This indicated the designed speed of compression and decompression in the experiment caused no damage to the divers' acoustic system, and the functions of their Eustachain tubes, middle and inner ears were normal during the diving test. PMID:7882734

  13. Absence of diuresis during a 7-day saturation dive at 2.5 ATA N2-O2.

    PubMed

    Niu, A K; Hong, S K; Claybaugh, J R; Goldinger, J M; Kwon, O; Li, M; Randall, E; Lundgren, C E

    1990-05-01

    Three male divers were studied for 2 days during each of the predive and postdive 1 ATA air control periods and for 7 days at 2.5 ATA (2.3 ATA N2 and 0.2 ATA O2). The chamber temperature was always maintained at a comfort level. Average urine flow remained at 1500 ml.day-1 during both predive and 2.5 ATA periods; urine osmolality also remained constant at around 700 mOSM/kg. On the other hand, daily excretion of Na increased significantly from 139 mEq during the predive period to 178 mEq at 2.5 ATA (P less than 0.05) but returned to the predive level during the postdive period. In contrast, daily K excretion decreased progressively with a significant decrease during the postdive period (P less than 0.05). Plasma osmolality, Na, and K remained unchanged, whereas a 6% reduction of total protein concentration at 2.5 ATA (P less than 0.05) was observed. A quantitatively similar decrease (8%) was observed for hematocrit during the 2.5 ATA period, which did not recover at postdive. These changes were accompanied by a significant increase in urinary excretion of antidiuretic hormone (P less than 0.05) and by decreases in both plasma renin and aldosterone (P less than 0.05) level and urinary excretion of aldosterone (P less than 0.05). Plasma atrial natriuretic factor remained unchanged throughout the entire dive period.

  14. [Respiratory changes in deep diving].

    PubMed

    Segadal, K; Gulsvik, A; Nicolaysen, G

    1989-01-30

    Deep diving refers to saturation diving to a depth of more than 180 m (1.9 MPa ambient pressure). In the 1990s diving to 400 m may be necessary on the Norwegian continental shelf. The safety margins are narrow and at such depths the respiratory system is subject to great strain. Respiratory resistance increases and the dynamic lung volumes are reduced as the pressure increases due to enhanced gas density. Helium is used together with oxygen as breathing gas and the lower density partly normalises the dynamic lung volumes. The respiratory system imposes clear limitations on the intensity and duration of physical work during deep diving. We lack systematic studies of lung mechanics, gas exchange and respiratory regulation in the different phases of deep dives. Demonstration of possible chronic occupational respiratory diseases connected to diving is dependent on follow-up over a long time.

  15. Respiratory changes with deep diving.

    PubMed

    Segadal, K; Gulsvik, A; Nicolaysen, G

    1990-01-01

    Deep diving refers to saturation diving to a depth of more than 180 m (1.9 MPa ambient pressure). In the 1990s diving to 400 m may be necessary on the Norwegian continental shelf. The safety margins are narrow and the respiratory system is subject to great strain at such depths. The respiratory resistance increases and the dynamic lung volumes are reduced as the pressure increases due to enhanced gas density. Helium is used together with oxygen as breathing gas and its lower density partly normalises the dynamic lung volumes. The respiratory system puts clear limitations on intensity and duration of physical work in deep diving. Systematic studies of lung mechanics, gas exchange and respiratory regulation in the different phases of deep dives are lacking. Detection of occupational respiratory disorder following diving are dependent on long-term follow-up.

  16. Diving injuries.

    PubMed

    Dickey, L S

    1984-01-01

    This is a collective review about the pathophysiology, diagnosis, and management of SCUBA and diving injuries by the emergency physician. These injuries can be classified into those resulting from the toxic effects of the inhaled gas, from the pressure changes in the water and gas mixture while diving, and from decompression sickness. With the increasing popularity of SCUBA diving, it is hoped that this discussion will enable a recognition of these injuries and therefore minimize the morbidity and mortality from them.

  17. Diving emergencies.

    PubMed

    DeGorordo, Antonio; Vallejo-Manzur, Federico; Chanin, Katia; Varon, Joseph

    2003-11-01

    Self-Contained Underwater Breathing Apparatus (SCUBA) diving popularity is increasing tremendously, reaching a total of 9 million people in the US during 2001, and 50,000 in the UK in 1985. Over the past 10 years, new advances, equipment improvements, and improved diver education have made SCUBA diving safer and more enjoyable. Most diving injuries are related to the behaviour of the gases and pressure changes during descent and ascent. The four main pathologies in diving medicine include: barotrauma (sinus, otic, and pulmonary); decompression illness (DCI); pulmonary edema and pharmacological; and toxic effects of increased partial pressures of gases. The clinical manifestations of a diving injury may be seen during a dive or up to 24 h after it. Physicians living far away from diving places are not excluded from the possibility of encountering diver-injured patients and therefore need to be aware of these injuries. This article reviews some of the principles of diving and pathophysiology of diving injuries as well as the acute treatment, and further management of these patients.

  18. Diving medicine.

    PubMed

    Bove, Alfred A

    2014-06-15

    Exposure to the undersea environment has unique effects on normal physiology and can result in unique disorders that require an understanding of the effects of pressure and inert gas supersaturation on organ function and knowledge of the appropriate therapies, which can include recompression in a hyperbaric chamber. The effects of Boyle's law result in changes in volume of gas-containing spaces when exposed to the increased pressure underwater. These effects can cause middle ear and sinus injury and lung barotrauma due to lung overexpansion during ascent from depth. Disorders related to diving have unique presentations, and an understanding of the high-pressure environment is needed to properly diagnose and manage these disorders. Breathing compressed air underwater results in increased dissolved inert gas in tissues and organs. On ascent after a diving exposure, the dissolved gas can achieve a supersaturated state and can form gas bubbles in blood and tissues, with resulting tissue and organ damage. Decompression sickness can involve the musculoskeletal system, skin, inner ear, brain, and spinal cord, with characteristic signs and symptoms. Usual therapy is recompression in a hyperbaric chamber following well-established protocols. Many recreational diving candidates seek medical clearance for diving, and healthcare providers must be knowledgeable of the environmental exposure and its effects on physiologic function to properly assess individuals for fitness to dive. This review provides a basis for understanding the diving environment and its accompanying disorders and provides a basis for assessment of fitness for diving. PMID:24869752

  19. Diving medicine.

    PubMed

    Bove, Alfred A

    2014-06-15

    Exposure to the undersea environment has unique effects on normal physiology and can result in unique disorders that require an understanding of the effects of pressure and inert gas supersaturation on organ function and knowledge of the appropriate therapies, which can include recompression in a hyperbaric chamber. The effects of Boyle's law result in changes in volume of gas-containing spaces when exposed to the increased pressure underwater. These effects can cause middle ear and sinus injury and lung barotrauma due to lung overexpansion during ascent from depth. Disorders related to diving have unique presentations, and an understanding of the high-pressure environment is needed to properly diagnose and manage these disorders. Breathing compressed air underwater results in increased dissolved inert gas in tissues and organs. On ascent after a diving exposure, the dissolved gas can achieve a supersaturated state and can form gas bubbles in blood and tissues, with resulting tissue and organ damage. Decompression sickness can involve the musculoskeletal system, skin, inner ear, brain, and spinal cord, with characteristic signs and symptoms. Usual therapy is recompression in a hyperbaric chamber following well-established protocols. Many recreational diving candidates seek medical clearance for diving, and healthcare providers must be knowledgeable of the environmental exposure and its effects on physiologic function to properly assess individuals for fitness to dive. This review provides a basis for understanding the diving environment and its accompanying disorders and provides a basis for assessment of fitness for diving.

  20. Occupational differences between conventional and saturation divers.

    PubMed

    Biersner, R J; Hall, D A; Linaweaver, P G

    1976-01-01

    Diving experiences of 53 Divers First Class attending the U.S. Navy Saturation Diver Training Program were compared to 155 Divers First Class performing routine operational dives. The two groups were matched for years of diving experience, total number of dives, and total number of SCUBA dives. The Diving Experience Questionnaire (DEQ), which consisted of 43 items dealing with specific diving conditions and activites, was used to document the diving backgrounds of the two groups. Five of the 43 items were found to significantly and uniquely differentiate between the two groups. Those attending the Saturation Diving Program a) made more dives between 46-61 m (151-200 ft), b) had more experience with semiclosed-circuit SCUBA, c) attended more deep-diving training courses, d) made fewer dives in water warmer than 70 degrees F, and e) had fewer specialized qualifications outside deep diving. The multiple regression analysis which differentiated between the two groups resulted in an R of 0.48. These five items indicate that volunteering for saturation diving is consistent or congruent with past deep-diving experience, while remaining in conventional diving is congruent with previous shallow-water experience. These results indicate that the DEQ may be a highly useful method of differentiating between experienced divers.

  1. Diving medicine.

    PubMed

    Benton, P J; Glover, M A

    2006-01-01

    Recreational diving developed in the late 1940s when self-contained underwater breathing apparatus (SCUBA) first became available for civilian use. At the same time the development of the commercial airliner, in particular the jet airliner, made possible the concept of international travel for pleasure as opposed to business. Over the past 50 years the number of international tourists has increased by over 2500% from a mere 25 million in 1950 to over 700 million in 2002 (Treadwell TL. Trends in travel. In: Zuckerman JN, editor. Principles and practice of travel medicine, 2001; p. 2-6). The popularity of recreational diving has also increased over the same period from an activity experienced by a small number of individuals in the early 1950s to an activity today enjoyed by many millions. The combination of increased international travel and the means by which to enter and explore the underwater world has led to diving becoming increasingly popular as a tourist activity.

  2. Diving mammals.

    PubMed

    Ponganis, Paul J

    2011-01-01

    The ability of diving mammals to forage at depth on a breath hold of air is dependent on gas exchange, both in the lung and in peripheral tissues. Anatomical and physiological adaptations in the respiratory system, cardiovascular system, blood and peripheral tissues contribute to the remarkable breath-hold capacities of these animals. The end results of these adaptations include efficient ventilation, enhanced oxygen storage, regulated transport and delivery of respiratory gases, extreme hypoxemic/ischemic tolerance, and pressure tolerance.

  3. Women and Diving.

    PubMed

    Kizer, K W

    1981-02-01

    In brief: Women who want to scuba dive should be physically fit and should not be overly dependent on a male diving buddy. In his discussion on diving and menstruation, the author says that postmenopausal women can dive safely, and those who are menstruating can dive within the limits of their comfort. He stresses that pregnant women and women who are trying to become pregnant should not dive. Women who use oral contraceptives should dive conservatively, because it is not known if birth control pills increase the risk of decompression sickness. The author also discusses thermal balance problems and when to resume diving after childbirth.

  4. 17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .../recommendation statement pursuant to section 14(d)(4) of the Securities Exchange Act of 1934 and rules 14d-1(b... 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the Securities Exchange..., DC 20549 Schedule 14D-9F Solicitation/Recommendation Statement Pursuant to Section 14(d)(4) of...

  5. 17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../recommendation statement pursuant to section 14(d)(4) of the Securities Exchange Act of 1934 and rules 14d-1(b... 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the Securities Exchange..., DC 20549 Schedule 14D-9F Solicitation/Recommendation Statement Pursuant to Section 14(d)(4) of...

  6. 17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .../recommendation statement pursuant to section 14(d)(4) of the Securities Exchange Act of 1934 and rules 14d-1(b... 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the Securities Exchange..., DC 20549 Schedule 14D-9F Solicitation/Recommendation Statement Pursuant to Section 14(d)(4) of...

  7. 17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .../recommendation statement pursuant to section 14(d)(4) of the Securities Exchange Act of 1934 and rules 14d-1(b... 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the Securities Exchange..., DC 20549 Schedule 14D-9F Solicitation/Recommendation Statement Pursuant to Section 14(d)(4) of...

  8. 17 CFR 240.14d-103 - Schedule 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .../recommendation statement pursuant to section 14(d)(4) of the Securities Exchange Act of 1934 and rules 14d-1(b... 14D-9F. Solicitation/recommendation statement pursuant to section 14(d)(4) of the Securities Exchange..., DC 20549 Schedule 14D-9F Solicitation/Recommendation Statement Pursuant to Section 14(d)(4) of...

  9. The sport diving employee.

    PubMed

    Milroy, W C

    1982-04-01

    As scuba diving becomes an increasingly popular recreational activity, the probability of the occupational health physician seeing diving-related disorders increases. Recognition of many of these disorders is unlikely if not specifically looked for and if any account of diving activities is not forth-coming. Diagnosis and management of diving diseases range from simple ear squeeze to decompression sickness. There are relative and absolute contradictions to sport diving.

  10. Polar Diving

    NASA Technical Reports Server (NTRS)

    2006-01-01

    3 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers exposed by erosion in a trough within the north polar residual cap of Mars, diving beneath a younger covering of polar materials. The layers have, since the Mariner 9 mission in 1972, been interpreted to be composed of a combination of dust and ice in unknown proportions. In this scene, a layer of solid carbon dioxide, which was deposited during the previous autumn and winter, blankets the trough as well as the adjacent terrain. Throughout northern spring, the carbon dioxide will be removed; by summer, the layers will be frost-free.

    Location near: 81.4oN, 352.2oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

  11. Diving Medicine: Frequently Asked Questions

    MedlinePlus

    ... re-evaluating your fitness to dive. Thyroid Conditions Fitness to Dive Asthma and Scuba Diving Bone Considerations ... Healthy, But Overweight DAN Discusses the Issue of Fitness and Diving By Joel Dovenbarger, Vice President, DAN ...

  12. Neurological long term consequences of deep diving.

    PubMed

    Todnem, K; Nyland, H; Skeidsvoll, H; Svihus, R; Rinck, P; Kambestad, B K; Riise, T; Aarli, J A

    1991-04-01

    Forty commercial saturation divers, mean age 34.9 (range 24-49) years, were examined one to seven years after their last deep dive (190-500 metres of seawater). Four had by then lost their divers' licence because of neurological problems. Twenty seven (68%) had been selected by neurological examination and electroencephalography before the deep dives. The control group consisted of 100 men, mean age 34.0 (range 22-48) years. The divers reported significantly more symptoms from the nervous system. Concentration difficulties and paraesthesia in feet and hands were common. They had more abnormal neurological findings by neurological examination compatible with dysfunction in the lumbar spinal cord or roots. They also had a larger proportion of abnormal electroencephalograms than the controls. The neurological symptoms and findings were highly significantly correlated with exposure to deep diving (depth included), but even more significantly correlated to air and saturation diving and prevalence of decompression sickness. Visual evoked potentials, brainstem auditory evoked potentials, and magnetic resonance imaging of the brain did not show more abnormal findings in the divers. Four (10%) divers had had episodes of cerebral dysfunction during or after the dives; two had had seizures, one had had transitory cerebral ischaemia and one had had transitory global amnesia. It is concluded that deep diving may have a long term effect on the nervous system of the divers.

  13. Travelers' Health: Scuba Diving

    MedlinePlus

    ... no-decompression limits of their dive tables or computers. Risk factors for DCI are primarily dive depth, ... 12]. Available from: http://www.diversalertnetwork.org/research/projects/fad/workshop/FADWorkshopProceedings.pdf . Chapter 2 - Environmental Hazards ...

  14. [The research progress of diving medicine in China].

    PubMed

    Fang, Yi-Qun; Bao, Xiao-Chen; Li, Ci; Meng, Miao; Yuan, Heng-Rong; Ma, Jun; Wang, Yan

    2012-11-01

    Diving medicine is one of the branches of military medicine, and plays an important role in naval development. This review introduces the progress of researches on undersea and hyperbaric physiology and medicine in the past few years in China. The article describes our research achievement in conventional diving and its medical support, researches on saturation diving and its medical support, submarine escape and its medical support, effects of hyperbaric environments and fast buoyancy ascent on immunological and cardiological functions. Diving disorders (including decompression sickness and oxygen toxicity) are also introduced.

  15. Scuba diving injuries.

    PubMed

    Replogle, W H; Sanders, S D; Keeton, J E; Phillips, D M

    1988-06-01

    Scuba diving has become increasingly popular, and family physicians may encounter patients who have been injured in a dive. Manifestations of diving injuries may not occur until 12 hours or more after a dive. Initial treatment, based on knowledge of the pathophysiology of decompression sickness, lung expansion injuries and ear barotrauma, may prevent severe and permanent sequelae. Decompression sickness and air embolism are medical emergencies.

  16. Diving and pregnancy.

    PubMed

    Camporesi, E M

    1996-08-01

    Scuba diving during pregnancy has increased in incidence as a result of substantial growth in the number of young females attracted to sport diving. This review summarizes the physiological changes induced by immersion, diving and decompression, on male and female divers. Furthermore, it extends to literature review, in animal models, of the susceptibility of a pregnant animal to diving decompression injury. Publications regarding reports of diving injury in pregnant humans are also reviewed, comprising very recent material from the sport diving community. It is concluded that there is no countraindication to diving for the normal, healthy, nonpregnant female. However, pregnant females should refrain from diving, because the fetus is not protected from decompression problems and is at risk of malformation and gas embolism after decompression disease. It is prudent to advise pregnant patients of the increased risk of diving problems for the fetus during pregnancy. However, should a woman have completed a dive during early pregnancy because she was unaware she was pregnant, the present evidence is not to recommend an abortion, because several normal pregnancies have been documented even if diving is continued. Snorkeling can still be practiced during pregnancy, but scuba diving should be discontinued until after the birth period.

  17. Norwegian deep diving trials.

    PubMed

    Tønjum, S

    1984-01-01

    In 1983 NUTEC, together with two diving companies, completed two dives with 12 divers (6 in each dive) to pressures equivalent to 350 m s.w., one dive lasted for 17 d, and the other, 24 d. The purpose of the dives was to demonstrate that the diving companies were prepared for diving to 300 m depth in the North Sea. No major medical or physiological problems arose during the dives, although all divers had minor symptoms of high pressure nervous syndrome during compressions. During decompression three decompression sickness incidents occurred, which involved pain only, and all were successfully treated. All divers went through comprehensive medical physiological examinations before and after the dives. No significant changes from values measured before diving have been found in the six divers who have so far been examined after diving, except that five of them were considerably more sensitive to CO2 after the dive than before. Several problems arose in connection with the divers' breathing equipment, thermal protection and communication, which need to be improved.

  18. Fatal diving accidents in western Norway 1983-2007.

    PubMed

    Ramnefjell, M P; Morild, I; Mørk, S J; Lilleng, P K

    2012-11-30

    Despite efforts to reduce their number, fatal diving accidents still occur. The circumstances and post-mortem findings in 40 fatal diving accidents in western Norway from 1983 through 2007 were investigated. Diving experience, medical history and toxicology reports were retrieved. The material consisted of recreational divers, professional saturation divers and professional divers without experience with saturation. In 33 cases the diving equipment was examined as part of the forensic investigation. In 27 cases defects in the diving equipment were found. For six divers such defects were responsible for the fatal accidents. Eighteen divers died on the surface or less than 10 m below surface. Five divers reached below 100 msw, and two of them died at this depth. The fatalities were not season-dependent. However, wave-height and strength of currents were influential factors in some cases. Twelve divers were diving alone. Twenty divers had one buddy, 9 of these divers were alone at the time of death. The cause of death was drowning in 31 out of 40 divers; one of them had a high blood-ethanol concentration, in two other divers ethanol was found in the urine, indicating previous ethanol consumption. Nine divers died from sudden decompression, pulmonary barotraumas, underwater trauma and natural causes. The study shows that most of the fatal diving accidents could be avoided if adequate diving safety procedures had been followed.

  19. [Scuba diving: practical aspects].

    PubMed

    Ewalenko, M

    2002-09-01

    Keeping in mind some fundamental physic's laws permits to better understand the risks of scuba diving. Essentially, it concerns Boyle's-Mariotte's law (pressure/volume relationship), Dalton's and Henry's laws on the gases partial pressures. Contra-indications of scuba diving depend on the possibility of accidents due to preexisting diseases. The most frequent accidents occur in the O.R.L. and pulmonary systems with the risk of barotraumas, and also in the cardiovascular system with the risk of fainting, uncontrolled ascent to the surface and even drowning. The aptitude test is essential to evaluate and minimize these risks with judicious advices. Generally, complementary tests are performed. In some cases, diving must be limited to "recreational diving", and sporting deep diving, where the conditions are more tiring and hard, must be discouraged. A list is added to the paper, to assist those with any medical problem related with scuba diving, to find informations and advices. PMID:12422438

  20. [Scuba diving: practical aspects].

    PubMed

    Ewalenko, M

    2002-09-01

    Keeping in mind some fundamental physic's laws permits to better understand the risks of scuba diving. Essentially, it concerns Boyle's-Mariotte's law (pressure/volume relationship), Dalton's and Henry's laws on the gases partial pressures. Contra-indications of scuba diving depend on the possibility of accidents due to preexisting diseases. The most frequent accidents occur in the O.R.L. and pulmonary systems with the risk of barotraumas, and also in the cardiovascular system with the risk of fainting, uncontrolled ascent to the surface and even drowning. The aptitude test is essential to evaluate and minimize these risks with judicious advices. Generally, complementary tests are performed. In some cases, diving must be limited to "recreational diving", and sporting deep diving, where the conditions are more tiring and hard, must be discouraged. A list is added to the paper, to assist those with any medical problem related with scuba diving, to find informations and advices.

  1. Bleomycin and scuba diving: to dive or not to dive?

    PubMed

    Huls, G; ten Bokkel Huinink, D

    2003-02-01

    Bleomycin is to treat patients with testicular cancer and lymphoma. Bleomycin can bind to DNA and chelate iron. The resulting complex can form an intermediate capable of interacting with oxygen to produce reactive oxygen species, particularly superoxide. Administrating high-inspired oxygen concentrations (e.g. during anaesthesia or acute illness) has been reported to exacerbate pulmonary injury. The duration of risk after bleomycin chemotherapy is unknown. Here we discuss our advice to a young male patient, who was successfully treated with bleomycin for testicular cancer, concerning the safety to return to scuba diving. Since scuba divers are exposed to high partial oxygen pressures (depending on the depth of the dive) we discouraged this patient from resuming scuba diving.

  2. [Lungs et diving].

    PubMed

    Héritier, F; Avanzi, P; Nicod, L

    2014-11-19

    Whilst underwater, the body is submitted to significant variations of the surrounding pressure according to the depth. These conditions modify the hemodynamic and the ventilatory mechanics considerably. Some repercussions, like pulmonary barotrauma, are related to simple physical phenomena. Others, like decompression sickness, are due to more com- plex processes. Breath-hold diving disrupts haematosis and can be complicated by alveolar haemorrhage and loss of consciousness. Acute pulmonary oedema during scuba-diving, breath-hold diving and swimming has been reported more recently. In case of pulmonary disorders scuba-diving is contraindicated most of the time. It is therefore highly recommended to seek medical advice to prevent problems. PMID:25603564

  3. Bradycardia during human diving.

    PubMed

    Landsberg, P G

    1975-04-01

    The bradycardial response to the diving reflex, which occurs in man and in diving animals, is thought to be a physiologically protective oxygen-conserving mechanism whereby the animal is kept alive during submergence. The physiology and nervous pathways are not yet fully understood, but several investigators have pointed out the potentially fatal outcome of an accentuated diving reflex. the CO2 content of the peripheral venous blood has been proved variable and unpredictable during the hyperventilation-breath-hold dive cycle in man. A group of 8 male divers (average age 34 years) was investigated during breathhold dives to 3,3 m in a swimming pool. Heart rates were recorded and compared at various stages during breath-hold and SCUBA (self-contained underwater breathing apparatus) dives, viz. when resting on the surface, breath-holding, hyperventilating and swimming underwater. Two divers performed extreme breathhold endurance tests lasting 135 seconds underwater. All divers had a tachycardia after hyperventilation and a bradycardia after breathhold diving, lasting 80-100 seconds. Extrasystoles were recorded during some of the breathhold dives. Prolonged submergence caused extreme bradycardia (24/min) with central cyanosis. Bradycardia during diving may be a physiological )2-conserving reflex or the start of a pathophysiological asphyxial response.

  4. Recreational scuba diving injuries.

    PubMed

    Clenney, T L; Lassen, L F

    1996-04-01

    Because of the increasing popularity of recreational scuba diving, primary care physicians should be familiar with common diving injuries. One form of barotrauma, middle ear squeeze, is the most common diving injury. Other important diving injuries include inner ear barotrauma and pulmonary barotrauma. Arterial gas embolism, a potentially life-threatening form of pulmonary barotrauma, requires hyperbaric treatment. Decompression sickness is the result of bubble formation in body tissue. Symptoms of decompression sickness range from joint pain to neurologic or pulmonary problems. Recompression is the mainstay of treatment.

  5. [Lungs et diving].

    PubMed

    Héritier, F; Avanzi, P; Nicod, L

    2014-11-19

    Whilst underwater, the body is submitted to significant variations of the surrounding pressure according to the depth. These conditions modify the hemodynamic and the ventilatory mechanics considerably. Some repercussions, like pulmonary barotrauma, are related to simple physical phenomena. Others, like decompression sickness, are due to more com- plex processes. Breath-hold diving disrupts haematosis and can be complicated by alveolar haemorrhage and loss of consciousness. Acute pulmonary oedema during scuba-diving, breath-hold diving and swimming has been reported more recently. In case of pulmonary disorders scuba-diving is contraindicated most of the time. It is therefore highly recommended to seek medical advice to prevent problems.

  6. Deepwater advanced diving systems that support the offshore oil field

    SciTech Connect

    Carnevale, S.J.

    1983-03-01

    This paper reviews deepwater diving technology which provides offshore oilfield support during all phases of exploration, construction and production. Mobile Observation Bells (MOB), Atmospheric Diving Suits (ADS), Remotely-Operated Vehicles (ROV), and saturation diving techniques are discussed. The term ''deep water'' is defined in relation to the water depths off the U.S. west coast. All diving system parameters are analyzed for each alternative; cost-effectiveness and safety are the two main objectives. Specific jobs are described which have used this high technology equipment for offshore operations on the U.S. west coast. These include drilling rig support, platform inspection and maintenance, and pipeline construction. Finally, future developments in diving systems are discussed.

  7. [Inner ear decompression sickness following a scuba dive].

    PubMed

    Satoh, M; Kitahara, S; Inouye, T; Ikeda, T

    1992-04-01

    Inner ear decompression sickness (IEDCS) is one form of Type II decompression sickness. Most cases of IEDCS have been associated with saturation dives, so there are very few reports of occurrence following shallow scuba dives. We present here the case of a diver who suffered from IEDCS following a shallow scuba dive (30m), and was successfully treated by the protocol outlined in U.S. Navy treatment table 6. This case suggests that there is the possibility of occurrence of IEDCS, even following a shallow scuba dive, if proper decompression procedures are not adhered to. In addition, detailed analysis of diving profiles should be used to distinguish the inner ear dysfunction seen in some divers from inner ear barotrauma which may be attributable to IEDCS.

  8. Deep-diving dinosaurs

    NASA Astrophysics Data System (ADS)

    Hayman, John

    2012-08-01

    Dysbaric bone necrosis demonstrated in ichthyosaurs may be the result of prolonged deep diving rather than rapid ascent to escape predators. The bone lesions show structural and anatomical similarity to those that may occur in human divers and in the deep diving sperm whale, Physeter macrocephalus.

  9. [Asthma and scuba diving].

    PubMed

    Héritier, Francis; Leuenberger, Philippe

    2003-02-01

    In scuba diving, the density of the gases supplied increases with depth. During ascent, overinflation of the lungs is avoided by exhalation. In case of airway obstruction, the theoretical risk of pulmonary barotrauma and drowning increases. For this reason, asthma has been considered as a contraindication to scuba diving. This recommendation is often ignored and many people with asthma dive, apparently without problems. Certifying that an asthmatic patient is fit to dive remains a controversial and difficult matter. In case of mild intermittent asthma, scuba diving seems possible when the pulmonary function test is normal and the patient is asymptomatic, including during exercise and exposure to cold air. The asthmatic diver should be fully informed of the risks incurred and should notify his or her informed-consent to the physician.

  10. Advanced dive monitoring system.

    PubMed

    Sternberger, W I; Goemmer, S A

    1999-01-01

    The US Navy supports deep diving operations with a variety of mixed-gas life support systems. A systems engineering study was conducted for the Naval Experimental Dive Unit (Panama City, FL) to develop a concept design for an advanced dive monitoring system. The monitoring system is intended primarily to enhance diver safety and secondarily to support diving medicine research. Distinct monitoring categories of diver physiology, life support system, and environment are integrated in the monitoring system. A system concept is proposed that accommodates real-time and quantitative measurements, noninvasive physiological monitoring, and a flexible and expandable implementation architecture. Human factors and ergonomic design considerations have been emphasized to assure that there is no impact on the diver's primary mission. The Navy has accepted the resultant system requirements and the basic design concept. A number of monitoring components have been implemented and successfully support deep diving operations.

  11. [Asthma and diving].

    PubMed

    Wurzinger, G

    1999-01-01

    Until recently asthma was considered a contraindication for scuba diving due to possible "air trapping" and subsequent barotrauma. However, in view of the wide prevalence and heterogeneity of the illness this is no longer justified. There are, nevertheless, certain prerequisites for diving with asthma: a complete anamnesis and an analysis of the pulmonary function, an exact diagnosis of the trigger factors as well as of the bronchial hyperreactivity in order to correctly ascertain the asthma level. When scuba diving, asthmatics need to observe certain rules. Still, some types of asthma remain incompatible with diving. Among these are the pseudo-allergic, exercise-induced, and psychogenic-induced asthma as well as allergic bronchopulmonal aspergillosis. Asthma due to bronchial infections and GERD are considered relative contraindications.

  12. Diving dynamics of seabirds

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan; Chang, Brian; Croson, Matt; Straker, Lorian; Dove, Carla

    2015-03-01

    Diving is the activity of falling from air into water, which is somewhat dangerous due to the impact. Humans dive for entertainments less than 20 meters high, however seabirds dive as a hunting mechanism from more than 20 meters high. Moreover, most birds including seabirds have a slender and long neck compared to many other animals, which can potentially be the weakest part of the body upon axial impact compression. Motivated by the diving dynamics, we investigate the effect of surface and geometric configurations on structures consisting of a beak-like cone and a neck-like elastic beam. A transition from non-buckling to buckling is characterized and understood through physical experiments and an analytical model.

  13. Scuba diving accidents.

    PubMed

    Dembert, M L

    1977-08-01

    The principal scuba diving medical problems of barotrauma, air embolism and decompression sickness have as their pathophysiologic basis the Ideal Gas Law and Boyle's Law. Hyperbaric chamber recompression therapy is the only definitive treatment of air embolism and decompression sickness. However, with a basic knowledge of diving medicine, the family physician can provide effective supportive care to the patient prior to initiation of hyperbaric therapy.

  14. [Vertigo and diving].

    PubMed

    Calvet, H; Serrano, E; Pessey, J J; Lacomme, Y

    1992-01-01

    The appearance of a vertigo during scuba-diving result from different pathophysiological mechanism at which oppose specific therapeutic. Whether it's during barotrauma or decompression accident, the vestibular reach can cause drowning. It is possible to make the difference between barotrauma and decompression accident, with the good study of the scuba-diving and the time when the vertigo has came. So, the therapeutic will use recompression in a multiplace hyperbaric chamber or only hyperbaric oxygen.

  15. Scuba diving accidents.

    PubMed

    Dembert, M L

    1977-08-01

    The principal scuba diving medical problems of barotrauma, air embolism and decompression sickness have as their pathophysiologic basis the Ideal Gas Law and Boyle's Law. Hyperbaric chamber recompression therapy is the only definitive treatment of air embolism and decompression sickness. However, with a basic knowledge of diving medicine, the family physician can provide effective supportive care to the patient prior to initiation of hyperbaric therapy. PMID:888755

  16. [Lung edema in scuba diving].

    PubMed

    Hempe, S; Lierz, P

    2003-10-01

    The management of a diving-related emergency is frequently a great challenge for an emergency physician without a special diving medicine training or experiences. Almost every physician knows something about the medical therapy of diving-related accidents which are combined with a barotrauma or a decompression sickness. But there are still some rare symptoms and organ affections of diving-related emergencies which are unknown in common. In consideration of the present case of an acute diving-related lung edema we discuss the different reasons and differential diagnosis of diving emergencies.

  17. Extreme diving of beaked whales.

    PubMed

    Tyack, Peter L; Johnson, Mark; Soto, Natacha Aguilar; Sturlese, Albert; Madsen, Peter T

    2006-11-01

    Sound-and-orientation recording tags (DTAGs) were used to study 10 beaked whales of two poorly known species, Ziphius cavirostris (Zc) and Mesoplodon densirostris (Md). Acoustic behaviour in the deep foraging dives performed by both species (Zc: 28 dives by seven individuals; Md: 16 dives by three individuals) shows that they hunt by echolocation in deep water between 222 and 1885 m, attempting to capture about 30 prey/dive. This food source is so deep that the average foraging dives were deeper (Zc: 1070 m; Md: 835 m) and longer (Zc: 58 min; Md: 47 min) than reported for any other air-breathing species. A series of shallower dives, containing no indications of foraging, followed most deep foraging dives. The average interval between deep foraging dives was 63 min for Zc and 92 min for Md. This long an interval may be required for beaked whales to recover from an oxygen debt accrued in the deep foraging dives, which last about twice the estimated aerobic dive limit. Recent reports of gas emboli in beaked whales stranded during naval sonar exercises have led to the hypothesis that their deep-diving may make them especially vulnerable to decompression. Using current models of breath-hold diving, we infer that their natural diving behaviour is inconsistent with known problems of acute nitrogen supersaturation and embolism. If the assumptions of these models are correct for beaked whales, then possible decompression problems are more likely to result from an abnormal behavioural response to sonar.

  18. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... GENERAL PROVISIONS Commercial Diving Operations Operations § 197.410 Dive procedures. (a) The diving supervisor shall insure that— (1) Before commencing diving operations, dive team members are briefed on— (i... safety of the diving operation; and (iii) Any modifications to the operations manual or...

  19. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... GENERAL PROVISIONS Commercial Diving Operations Operations § 197.410 Dive procedures. (a) The diving supervisor shall insure that— (1) Before commencing diving operations, dive team members are briefed on— (i... safety of the diving operation; and (iii) Any modifications to the operations manual or...

  20. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... GENERAL PROVISIONS Commercial Diving Operations Operations § 197.410 Dive procedures. (a) The diving supervisor shall insure that— (1) Before commencing diving operations, dive team members are briefed on— (i... safety of the diving operation; and (iii) Any modifications to the operations manual or...

  1. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  2. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  3. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GENERAL PROVISIONS Commercial Diving Operations Operations § 197.410 Dive procedures. (a) The diving supervisor shall insure that— (1) Before commencing diving operations, dive team members are briefed on— (i... safety of the diving operation; and (iii) Any modifications to the operations manual or...

  4. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  5. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  6. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  7. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  8. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  9. Can asthmatic subjects dive?

    PubMed

    Adir, Yochai; Bove, Alfred A

    2016-06-01

    Recreational diving with self-contained underwater breathing apparatus (scuba) has grown in popularity. Asthma is a common disease with a similar prevalence in divers as in the general population. Due to theoretical concern about an increased risk for pulmonary barotrauma and decompression sickness in asthmatic divers, in the past the approach to asthmatic diver candidates was very conservative, with scuba disallowed. However, experience in the field and data in the current literature do not support this dogmatic approach. In this review the theoretical risk factors of diving with asthma, the epidemiological data and the recommended approach to the asthmatic diver candidate will be described. PMID:27246598

  10. Applied physiology of diving.

    PubMed

    Lin, Y C

    1988-01-01

    Recreational diving is a popular sport, although human ability to stay in and under water is severely limited physiologically. An understanding of these limitations enhances safety and enjoyment of sports diving. Breath-hold diving involves head-out water immersion, apnoea and submersion, exercise, cold stress, and pressure exposure. Each of these components, by itself, elicits prominent and specific physiological effects. Combination of these factors produces a unique and interesting physiological response generally known as diving reflex. Humans display weak diving responses, but exhibit no oxygen conservation function. Nevertheless, application of diving-induced physiological changes is now finding its way into clinical practice. Apnoea, face immersion, and head-out water immersion all show promise of clinical application. There are several spin-offs from diving research worth noting. Diuresis, enhancement of cardiac performance, and redistribution of blood flow, all produced by head-out water immersion, have been shown to be clinically useful, besides providing physiological data useful to space travel. Results from investigations on apnoea have been shown to be relevant to the following: treating some forms of cardiac arrhythmias; understanding drowning, sudden infant death syndrome and sleep apnoea; and confirming hyperventilation as the major cause of drowning. In comparison to marine mammals, humans are poor divers because of severe physiological constraints which limit their breath-hold time, diving depth, and ability to conserve body heat. Although under special circumstances humans can achieve unusually long breath-hold time and reach exceptional depth with a single breath, the sustainable working time and depth are only about 1 minute and 5 metres, respectively. Hypothermia inevitably results in divers working in the ocean. Without thermal protection, the intolerable limit of 35 degrees C is reached within 30 minutes in winter (10 degrees C) water and

  11. Can asthmatic subjects dive?

    PubMed

    Adir, Yochai; Bove, Alfred A

    2016-06-01

    Recreational diving with self-contained underwater breathing apparatus (scuba) has grown in popularity. Asthma is a common disease with a similar prevalence in divers as in the general population. Due to theoretical concern about an increased risk for pulmonary barotrauma and decompression sickness in asthmatic divers, in the past the approach to asthmatic diver candidates was very conservative, with scuba disallowed. However, experience in the field and data in the current literature do not support this dogmatic approach. In this review the theoretical risk factors of diving with asthma, the epidemiological data and the recommended approach to the asthmatic diver candidate will be described.

  12. The Physics of Diving

    NASA Astrophysics Data System (ADS)

    Katzgraber, Helmut

    2007-10-01

    The underwater world, and in particular our oceans, represent a final frontier of exploration. In the past, studying the underwater fauna and flora used to be a dangerous undertaking reserved to professional divers. Technological advances over the last 50 years have given sports divers the opportunity to explore this fascinating world using self-contained underwater breathing apparatuses (SCUBA). Despite these technological advances humans have to cope with an unusual environment: perception is different underwater and there is always a risk of decompression illness due to the ambient pressure. After a brief overview of SCUBA diving, some physical phenomena particular to diving will be presented.

  13. Lung collapse in the diving sea lion: hold the nitrogen and save the oxygen

    PubMed Central

    McDonald, Birgitte I.; Ponganis, Paul J.

    2012-01-01

    Lung collapse is considered the primary mechanism that limits nitrogen absorption and decreases the risk of decompression sickness in deep-diving marine mammals. Continuous arterial partial pressure of oxygen profiles in a free-diving female California sea lion (Zalophus californianus) revealed that (i) depth of lung collapse was near 225 m as evidenced by abrupt changes in during descent and ascent, (ii) depth of lung collapse was positively related to maximum dive depth, suggesting that the sea lion increased inhaled air volume in deeper dives and (iii) lung collapse at depth preserved a pulmonary oxygen reservoir that supplemented blood oxygen during ascent so that mean end-of-dive arterial was 74 ± 17 mmHg (greater than 85% haemoglobin saturation). Such information is critical to the understanding and the modelling of both nitrogen and oxygen transport in diving marine mammals. PMID:22993241

  14. Neurologic injuries from scuba diving.

    PubMed

    Hawes, Jodi; Massey, E Wayne

    2009-02-01

    Interest in scuba (self-contained underwater breathing apparatus) diving increased in the 1970s, and undersea diving continues to be a popular sport early in the 21st century, with approximately 3 million certified divers in the United States. The Divers Alert Network (DAN), an institution created in 1981 by the Commerce Department, National Oceanic and Atmospheric Administration, has collected diving injury data for US and Canadian divers since 1987 that can be studied to suggest the epidemiologic characteristics of diving. This article examines neurologic injuries resulting from scuba diving.

  15. Neurologic injuries from scuba diving.

    PubMed

    Hawes, Jodi; Massey, E Wayne

    2008-02-01

    Interest in scuba (self-contained underwater breathing apparatus) diving increased in the 1970s, and undersea diving continues to be a popular sport early in the 21st century, with approximately 3 million certified divers in the United States. The Divers Alert Network (DAN), an institution created in 1981 by the Commerce Department, National Oceanic and Atmospheric Administration, has collected diving injury data for US and Canadian divers since 1987 that can be studied to suggest the epidemiologic characteristics of diving. This article examines neurologic injuries resulting from scuba diving.

  16. Neurological effects of deep diving.

    PubMed

    Grønning, Marit; Aarli, Johan A

    2011-05-15

    Deep diving is defined as diving to depths more than 50 m of seawater (msw), and is mainly used for occupational and military purposes. A deep dive is characterized by the compression phase, the bottom time and the decompression phase. Neurological and neurophysiologic effects are demonstrated in divers during the compression phase and the bottom time. Immediate and transient neurological effects after deep dives have been shown in some divers. However, the results from the epidemiological studies regarding long term neurological effects from deep diving are conflicting and still not conclusive. Prospective clinical studies with sufficient power and sensitivity are needed to solve this very important issue.

  17. Dive into Scuba

    ERIC Educational Resources Information Center

    Coelho, Jeffrey; Fielitz, Lynn R.

    2006-01-01

    Scuba is a unique physical education activity that middle school and high school students can experience in physical education to provide them with the basic skills needed to enjoy the sport for many years to come. This article describes the basic scuba diving equipment, proper training and certification for instructors and students, facilities,…

  18. ASSESSMENT OF PLUME DIVING

    EPA Science Inventory

    This presentation presents an assessment of plume diving. Observations included: vertical plume delineation at East Patchogue, NY showed BTEX and MTBE plumes sinking on either side of a gravel pit; Lake Druid TCE plume sank beneath unlined drainage ditch; and aquifer recharge/dis...

  19. Diving into Oceans.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1992-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Diving Into Oceans." Contents are organized into the following sections: (1)…

  20. Neurology and diving.

    PubMed

    Massey, E Wayne; Moon, Richard E

    2014-01-01

    Diving exposes a person to the combined effects of increased ambient pressure and immersion. The reduction in pressure when surfacing can precipitate decompression sickness (DCS), caused by bubble formation within tissues due to inert gas supersaturation. Arterial gas embolism (AGE) can also occur due to pulmonary barotrauma as a result of breath holding during ascent or gas trapping due to disease, causing lung hyperexpansion, rupture and direct entry of alveolar gas into the blood. Bubble disease due to either DCS or AGE is collectively known as decompression illness. Tissue and intravascular bubbles can induce a cascade of events resulting in CNS injury. Manifestations of decompression illness can vary in severity, from mild (paresthesias, joint pains, fatigue) to severe (vertigo, hearing loss, paraplegia, quadriplegia). Particularly as these conditions are uncommon, early recognition is essential to provide appropriate management, consisting of first aid oxygen, targeted fluid resuscitation and hyperbaric oxygen, which is the definitive treatment. Less common neurologic conditions that do not require hyperbaric oxygen include rupture of a labyrinthine window due to inadequate equalization of middle ear pressure during descent, which can precipitate vertigo and hearing loss. Sinus and middle ear overpressurization during ascent can compress the trigeminal and facial nerves respectively, causing temporary facial hypesthesia and lower motor neuron facial weakness. Some conditions preclude safe diving, such as seizure disorders, since a convulsion underwater is likely to be fatal. Preventive measures to reduce neurologic complications of diving include exclusion of individuals with specific medical conditions and safe diving procedures, particularly related to descent and ascent.

  1. Human Simulated Diving Experiments.

    ERIC Educational Resources Information Center

    Bruce, David S.; Speck, Dexter F.

    1979-01-01

    This report details several simulated divinq experiments on the human. These are suitable for undergraduate or graduate laboratories in human or environmental physiology. The experiment demonstrates that a diving reflex is precipitated by both facial cooling and apnea. (Author/RE)

  2. [Asthma and scuba diving: can asthmatic patients dive?].

    PubMed

    Sade, Kobi; Wiesel, Ory; Kivity, Shmuel; Levo, Yoram

    2007-04-01

    Self-contained underwater breathing apparatus (scuba) diving has grown in popularity, with millions of divers enjoying the sport worldwide. This activity presents unique physical and physiological challenges to the respiratory system, raising numerous concerns about individuals with asthma who choose to dive. Asthma had traditionally been a contraindication to recreational diving, although this caveat has been ignored by large numbers of such patients. Herein we review the currently available literature to provide evidence-based evaluation of the risks associated with diving that are posed to asthmatics. Although there is some indication that asthmatics may be at an increased risk of pulmonary barotrauma, the risk seems to be small. Thus, under the right circumstances, patients with asthma can safely participate in recreational diving without any apparent increased risk of an asthma-related event. Decisions on whether or not diving is hazardous must be made on an individual basis and be founded upon an informed decision shared by both patient and physician.

  3. Neurology and diving.

    PubMed

    Massey, E Wayne; Moon, Richard E

    2014-01-01

    Diving exposes a person to the combined effects of increased ambient pressure and immersion. The reduction in pressure when surfacing can precipitate decompression sickness (DCS), caused by bubble formation within tissues due to inert gas supersaturation. Arterial gas embolism (AGE) can also occur due to pulmonary barotrauma as a result of breath holding during ascent or gas trapping due to disease, causing lung hyperexpansion, rupture and direct entry of alveolar gas into the blood. Bubble disease due to either DCS or AGE is collectively known as decompression illness. Tissue and intravascular bubbles can induce a cascade of events resulting in CNS injury. Manifestations of decompression illness can vary in severity, from mild (paresthesias, joint pains, fatigue) to severe (vertigo, hearing loss, paraplegia, quadriplegia). Particularly as these conditions are uncommon, early recognition is essential to provide appropriate management, consisting of first aid oxygen, targeted fluid resuscitation and hyperbaric oxygen, which is the definitive treatment. Less common neurologic conditions that do not require hyperbaric oxygen include rupture of a labyrinthine window due to inadequate equalization of middle ear pressure during descent, which can precipitate vertigo and hearing loss. Sinus and middle ear overpressurization during ascent can compress the trigeminal and facial nerves respectively, causing temporary facial hypesthesia and lower motor neuron facial weakness. Some conditions preclude safe diving, such as seizure disorders, since a convulsion underwater is likely to be fatal. Preventive measures to reduce neurologic complications of diving include exclusion of individuals with specific medical conditions and safe diving procedures, particularly related to descent and ascent. PMID:24365363

  4. Electrocardiographic aspects of deep dives in elite breath-hold divers.

    PubMed

    Lemaître, F; Lafay, V; Taylor, M; Costalat, G; Gardette, B

    2013-01-01

    The cardiac diving response, 12-lead electrocardiogram (ECG) and the prevalence, time of onset, and possible associations of cardiac arrhythmias were examined during deep breath-hold (BH) dives. Nine elite BH divers (33.2 +/- 3.6 years; mean +/- SD) performed one constant-weight dive of at least 75% of their best personal performance (70 +/- 7 meters for 141 +/- 22 seconds) wearing a 12-lead ECG Holter monitor. Diving parameters (depth and time), oxygen saturation (SaO2), blood lactate concentration and ventilatory parameters were also recorded. Bradycardia during these dives was pronounced (52.2 +/- 12.2%), with heart rates dropping to 46 +/- 10 beats/minute. The diving reflex was strong, overriding the stimulus of muscular exercise during the ascent phase of the dive for all divers. Classical arrhythmias occurred, mainly after surfacing, and some conduction alterations were detected at the bottom of the dives. The BH divers did not show any right shift of the QRS electrical axis during their dives.

  5. Scuba diving with cochlear implants.

    PubMed

    Kompis, Martin; Vibert, Dominique; Senn, Pascal; Vischer, Mattheus W; Häusler, Rudolf

    2003-05-01

    We report on a patient with bilateral cochlear implants (a Med-El Combi40 and a Med-El Combi40+), as well as considerable experience in scuba diving with both of his implants. After having been exposed to 68 and 89 dives, respectively, in depths of up to 43 m, both cochlear implants are in working order and the patient continues to receive excellent speech recognition scores with both cochlear implant systems. The presented data show that scuba diving after cochlear implantation is possible over a considerable number of dives without any major negative impact on the implants.

  6. A SCUBA-diving fatality.

    PubMed

    Haydon, J R; Williamson, J A; Ansford, A J; Sherif, S; Shapter, M J

    1985-11-11

    An investigation by a Naval Board of Inquiry into the circumstances of a fatal naval diving accident is presented. Although drowning contributed to the fatal outcome, massive arterial gas embolism is thought to have been the principal cause of death, and the value of post-mortem computed tomography scanning for its detection is demonstrated. The possibility is discussed of diver error due to unfamiliarity with equipment and procedures, compounded by nitrogen narcosis. The shortfall in expertise of coronial inquiries into diving deaths is emphasized against a background of increasing popularity of sports diving around Australia. The implications for the offshore industry are obvious and suggest the need for a federal diving inspectorate.

  7. Surface pauses in relation to dive duration in imperial cormorants; how much time for a breather?

    PubMed

    Wilson, Rory P; Quintana, Flavio

    2004-05-01

    Air-breathing animals diving to forage can optimize time underwater by diving with just enough oxygen for the projected performance underwater. By so doing they surface with minimal body oxygen levels, which leads to maximal rates of oxygen uptake. We examined whether imperial cormorants Phalacrocorax atriceps adhere to this by examining dive:pause ratios in birds diving for extended, continuous periods to constant depths, assuming that the oxygen used underwater was exactly replenished by the periods at the surface. Examination of the cumulative time spent in surface pauses relative to the cumulative time spent in diving showed that surface pauses increase according to a power curve function of time spent in the dive or water depth. In a simplistic model we considered the rate at which birds expended energy underwater to be constant and that the rate of oxygen replenishment during the surface pause was directly proportional to the oxygen deficit. We then worked out values for the rate constant for the surface pause before using this constant to examine bird body oxygen levels immediately pre- and post dive. The model predicted that imperial cormorants do not submerge with just enough oxygen to cover their projected dive performance but rather dive with substantial reserves, although these reserves decrease with increasing dive depth/duration. We speculate that these oxygen reserves may be used to enhance bird survival when rare events, such as the appearance of predators or discovery of large prey requiring extended handling time, occur. The form of the oxygen saturation curve over time at the surface means that the time costs for maintaining constant oxygen reserves become particularly onerous for long, deep dives, so the observed decrease in reserves with increasing dive duration is expected in animals benefiting by optimizing for time. PMID:15107434

  8. Fatty Acid use in Diving Mammals: More than Merely Fuel

    PubMed Central

    Trumble, Stephen J.; Kanatous, Shane B.

    2012-01-01

    Diving mammals, are under extreme pressure to conserve oxygen as well as produce adequate energy through aerobic pathways during breath-hold diving. Typically a major source of energy, lipids participate in structural and regulatory roles and have an important influence on the physiological functions of an organism. At the stoichiometric level, the metabolism of polyunsaturated fatty acids (PUFAs) utilizes less oxygen than metabolizing either monounsaturated fatty acids or saturated fatty acids (SFAs) and yields fewer ATP per same length fatty acid. However, there is evidence that indicates the cellular metabolic rate is directly correlated to the lipid composition of the membranes such that the greater the PUFA concentration in the membranes the greater the metabolic rate. These findings appear to be incompatible with diving mammals that ingest and metabolize high levels of unsaturated fatty acids while relying on stored oxygen. Growing evidence from birds to mammals including recent evidence in Weddell seals also indicates that at the whole animal level the utilization of PUFAs to fuel their metabolism actually conserves oxygen. In this paper, we make an initial attempt to ascertain the beneficial adaptations or limitations of lipids constituents and potential trade-offs in diving mammals. We discuss how changes in Antarctic climate are predicted to have numerous different environmental effects; such potential shifts in the availability of certain prey species or even changes in the lipid composition (increased SFA) of numerous fish species with increasing water temperatures and how this may impact the diving ability of Weddell seals. PMID:22707938

  9. Diving and chronic spontaneous pneumothorax.

    PubMed

    Ziser, A; Väänänen, A; Melamed, Y

    1985-02-01

    Diving and pneumothorax cannot go together. An air bubble between the visceral and the parietal pleura will change its size according to Boyle's law, and pneumothorax might increase in size during the ascent from a dive. We would like to present the case of a professional diver, who was engaged in active diving for a period of five months during which time he made 80 to 85 dives with pneumothorax. As far as we know, this is the first such case published in the medical literature. We should also like to emphasize the protracted nature of the pneumothorax, which persisted for that time without changing size. This diver had no medical problems with diving, and the deeper he descended, the better he felt. No tension pneumothorax ever occurred and the diagnosis was made by chance. PMID:3967535

  10. Continuous pulse oximetry in the breath-hold diving women of Korea and Japan.

    PubMed

    Stanek, K S; Guyton, G P; Hurford, W E; Park, Y S; Ahn, D W; Qvist, J; Falke, K J; Hong, S K; Kobayashi, K; Kobayashi, H

    1993-12-01

    Arterial oxygen saturation during breath-hold diving has not previously been measured continuously. We devised a submersible, waterproof, backpack computer to continuously record heart rate, depth, and arterial oxygen saturation (SPO2) as determined by earlobe pulse oximetry. Our measurements showed that one assisted (Funado) diver had reduced SPO2 values immediately after surfacing from 22 dives which lasted 23-76 s, from a mean of 99 +/- 1% SPO2 to 96 +/- 3% SPO2. SPO2 returned to 97 +/- 2% within 15 s after surfacing (P < 0.05 surface value differs from predive base line). Four unassisted (Cachido) divers showed no significant reduction of mean predive SPO2 below 98 +/- 2% at any time during the dive or recovery period in 92 routine dives lasting from 15 to 44 s. Upon surfacing from diving, mean SPO2 was 98 +/- 2% and the mean SPO2 15 s after surfacing was 97 +/- 3% for the unassisted divers. Three Cachido divers were asked to dive and breath hold for as long as possible. Mean SPO2 at the conclusion of breath holding was 73% after an average dive and breath hold lasting 69 s.

  11. Insights from venous oxygen profiles: oxygen utilization and management in diving California sea lions.

    PubMed

    McDonald, Birgitte I; Ponganis, Paul J

    2013-09-01

    The management and depletion of O2 stores underlie the aerobic dive capacities of marine mammals. The California sea lion (Zalophus californianus) presumably optimizes O2 store management during all dives, but approaches its physiological limits during deep dives to greater than 300 m depth. Blood O2 comprises the largest component of total body O2 stores in adult sea lions. Therefore, we investigated venous blood O2 depletion during dives of California sea lions during maternal foraging trips to sea by: (1) recording venous partial pressure of O2 (P(O2)) profiles during dives, (2) characterizing the O2-hemoglobin (Hb) dissociation curve of sea lion Hb and (3) converting the P(O2) profiles into percent Hb saturation (S(O2)) profiles using the dissociation curve. The O2-Hb dissociation curve was typical of other pinnipeds (P50=28±2 mmHg at pH 7.4). In 43% of dives, initial venous S(O2) values were greater than 78% (estimated resting venous S(O2)), indicative of arterialization of venous blood. Blood O2 was far from depleted during routine shallow dives, with minimum venous S(O2) values routinely greater than 50%. However, in deep dives greater than 4 min in duration, venous S(O2) reached minimum values below 5% prior to the end of the dive, but then increased during the last 30-60 s of ascent. These deep dive profiles were consistent with transient venous blood O2 depletion followed by partial restoration of venous O2 through pulmonary gas exchange and peripheral blood flow during ascent. These differences in venous O2 profiles between shallow and deep dives of sea lions reflect distinct strategies of O2 store management and suggest that underlying cardiovascular responses will also differ.

  12. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  13. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  14. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  15. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  16. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  17. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within the Preserve....

  18. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  19. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  20. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  1. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  2. Patent foramen ovale and diving.

    PubMed

    Germonpré, Peter

    2005-02-01

    Patency of the foramen ovale is a risk factor for DCS in SCUBA divers, even if they adhere to the currently accepted and used decompression tables. The primary cause of DCS, however, is the nitrogen bubble, not the PFO. There are a number of techniques any diver can use to minimize the occurrence of nitrogen bubbles after a dive. The authors current practice is to inform civilian sports divers of the increased risk and to advise them to adopt conservative dive profiles. This can be achieved by selecting a more conservative dive computer, performing only dives that do not require obligatory decompression stops, or using oxygen-enriched breathing gas mixtures("nitrox") while still diving on "air profiles" [56].Dive-safety organizations are currently under-taking studies aimed at proposing changes in the decompression algorithms to produce low-bubble dive tables [12]. In the meantime, PFO remains a reason for caution. Whether all divers should be screened for PFOis an ongoing discussion [50] in view of methodologic and practical issues outlined in this article. Any definitive recommendations can be made only after a careful, prospective evaluation of the real relative risk for DCS and long-term cerebral damage.

  3. Medical aspects of scuba diving.

    PubMed

    Suke, R

    1985-11-01

    Scuba divers may encounter dangerous levels of stress, due to increased ambient pressures and hostile environments. Divers therefore require a high level of mental and cardiorespiratory fitness. They must be informed of specific contraindications to diving. Family physicians with a basic knowledge of the medical aspects of scuba diving are in a very good position to examine and advise sports divers. Screening mainly involves an assessment of emotional stability and cardiorespiratory fitness, and an ear, nose and throat examination. Common problems suffered by scuba divers are discussed, as are temporary and permanent contraindications to diving.

  4. Medical Aspects of Scuba Diving

    PubMed Central

    Suke, Ralph

    1985-01-01

    Scuba divers may encounter dangerous levels of stress, due to increased ambient pressures and hostile environments. Divers therefore require a high level of mental and cardiorespiratory fitness. They must be informed of specific contraindications to diving. Family physicians with a basic knowledge of the medical aspects of scuba diving are in a very good position to examine and advise sports divers. Screening mainly involves an assessment of emotional stability and cardiorespiratory fitness, and an ear, nose and throat examination. Common problems suffered by scuba divers are discussed, as are temporary and permanent contraindications to diving. PMID:21274131

  5. [The cochlea and underwater diving].

    PubMed

    Renon, P; Lory, C; Casanova, M; Belliato, R; Peny, C

    1989-01-01

    Internal ear barotrauma are dangerous for cochlea. Out of accidents, long-term scuba diving involves no deafness. A study carries on 272 skin divers of the French Navy shows that only presbyacusis and industrial noise exposure give audiometric damages.

  6. Neurologic complications of scuba diving.

    PubMed

    Newton, H B

    2001-06-01

    Recreational scuba diving has become a popular sport in the United States, with almost 9 million certified divers. When severe diving injury occurs, the nervous system is frequently involved. In dive-related barotrauma, compressed or expanding gas within the ears, sinuses and lungs causes various forms of neurologic injury. Otic barotrauma often induces pain, vertigo and hearing loss. In pulmonary barotrauma of ascent, lung damage can precipitate arterial gas embolism, causing blockage of cerebral blood vessels and alterations of consciousness, seizures and focal neurologic deficits. In patients with decompression sickness, the vestibular system, spinal cord and brain are affected by the formation of nitrogen bubbles. Common signs and symptoms include vertigo, thoracic myelopathy with leg weakness, confusion, headache and hemiparesis. Other diving-related neurologic complications include headache and oxygen toxicity.

  7. [Otorhinolaryngologic aspects of diving sports].

    PubMed

    Strutz, J

    1993-08-01

    ENT disorders are the most common of all medical problems of diving. This review summarizes the specific conditions and ENT diseases in Scuba diving. During compression failure to equalize the pressure of air-filled cavities surrounded by bone deprives the middle ear or sinuses of aeration. Middle ear barotrauma is the most common barotrauma encountered in divers while sinus barotrauma and especially inner ear barotrauma (with rupture of the round or oval window) are less common. Decompression sickness in primarily the result of inert gas bubbles; deafness and vertigo may result if the inner ear is involved. The ENT examination necessary for assessment of diving fitness focuses on the middle and inner ear as well as the nose, sinuses and larynx. A list of ENT contra-indications is presented that mandate temporary or permanent disqualification from diving.

  8. EPO modulation in a 14-days undersea scuba dive.

    PubMed

    Revelli, L; Vagnoni, S; D'Amore, A; Di Stasio, E; Lombardi, C P; Storti, G; Proietti, R; Balestra, C; Ricerca, B M

    2013-10-01

    Erythropoiesis is affected during deep saturation dives. The mechanism should be related to a downregulation of serum Erythropoietin (s-EPO) concentration or to a toxic effect of the hyperbaric hyperoxia. We evaluated s-EPO and other haematological parameters in 6 scuba divers before, during and after a 14-days guinness saturation dive (8-10 m). Athletes were breathing air at 1.8-2 ATA, under the control of a team of physicians. Serum parameters were measured before diving (T0) and: 7 days (T1), 14 days (T2) after the beginning of the dive and 2 h (T3) and 24 h (T4) after resurfacing. Hgb, and many other haematological parameters did not change whereas Ht, s-EPO, the ratio between s-EPO predicted and that observed and reticulocytes (absolute, percent) declined progressively from T0 to T3. At T4 a significant rise in s-EPO was observed. Hgb did not vary but erythropoiesis seemed to be affected as s-EPO and reticulocyte counts showed. All these changes were statistically significant. The experiment, conducted in realistic conditions of dive length, oxygen concentration and pressure, allows us to formulate some hypotheses about the role of prolonged hyperbarism on erythropoiesis. The s-EPO rise, 24 h after resurfacing, is clearly documented and related to the "Normobaric Oxygen Paradox". This evidence suggests interesting hypotheses for new clinical applications such as modulation of s-EPO production and Hgb content triggered by appropriate O₂ administration in pre-surgical patients or in some anemic disease.

  9. Control of ventilation in diving birds.

    PubMed

    Butler, Patrick J; Halsey, Lewis G

    2008-01-01

    Studies on diving ducks indicate that the carotid bodies affect dive duration when the birds are hypoxic before a dive but not when they are hypercapnic. When close to their critical concentrations (beyond which the ducks will not dive), both oxygen and carbon dioxide reduce dive duration but hypercapnia has a much larger influence than hypoxia on surface duration. Also, excessive removal of carbon dioxide before a dive may be as important a factor in preparing for that dive as the replacement of the oxygen used during the previous dive. This observation is compatible with a physiological model of the control of diving behaviour in the Weddell seal which emphasises the significance of the level of carbon dioxide in the blood perfusing the brain. PMID:18085287

  10. Free and forced diving in ducks: habituation of the initial dive response.

    PubMed

    Gabrielsen, G W

    1985-01-01

    Response habituation in pekin ducks was observed during a study of the early phase of the dive response. This is interpreted as the orienting response and strongly suggests higher CNS influence in the initial phase of the forced immersion heart rate response. Repeated forced dives (20-30 s) of restrained ducks were performed with 40 s recovery period between dives. During the first dives, the ducks' heart rates fell 69% (272 +/- 8 to 83 +/- 32 beats X min-1, means +/- SE) of pre-dive values. The extent of this bradycardia decreased progressively as the dives were repeated. After 60 dives, the heart rates dropped by only 29% (248 +/- 3 to 177 +/- 25 beats X min-1 for pre-dive value). Voluntary diving of the ducks, lasting 5-20 s, caused no diving bradycardia. They showed breathing tachycardia which caused a 25% increase in heart rates above diving level (160 +/- 5 to 200 +/- 12 beats X min-1). PMID:3969834

  11. Upper respiratory tract and aural flora of saturation divers.

    PubMed Central

    Jones, D M; Davis, P

    1978-01-01

    The conditions of helium saturation diving promote the proliferation of Gram-negative bacterial species in the external auditory meatus of divers. These changes in flora occurred in the absence of operational diving, that is, no contact with water. The colonising bacteria were autogenous in origin and cross-colonisation was observed between divers. On return to normal atmospheric conditions the aural flora became predominantly Gram-positive again within 48 hours. PMID:690235

  12. [Diving accidents. Emergency treatment of serious diving accidents].

    PubMed

    Schröder, S; Lier, H; Wiese, S

    2004-11-01

    Decompression injuries are potentially life-threatening incidents mainly due to a rapid decline in ambient pressure. Decompression illness (DCI) results from the presence of gas bubbles in the blood and tissue. DCI may be classified as decompression sickness (DCS) generated from the liberation of gas bubbles following an oversaturation of tissues with inert gas and arterial gas embolism (AGE) mainly due to pulmonary barotrauma. People working under hyperbaric pressure, e.g. in a caisson for general construction under water, and scuba divers are exposed to certain risks. Diving accidents can be fatal and are often characterized by organ dysfunction, especially neurological deficits. They have become comparatively rare among professional divers and workers. However, since recreational scuba diving is gaining more and more popularity there is an increasing likelihood of severe diving accidents. Thus, emergency staff working close to areas with a high scuba diving activity, e.g. lakes or rivers, may be called more frequently to a scuba diving accident. The correct and professional emergency treatment on site, especially the immediate and continuous administration of normobaric oxygen, is decisive for the outcome of the accident victim. The definitive treatment includes rapid recompression with hyperbaric oxygen. The value of adjunctive medication, however, remains controversial.

  13. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Surface-supplied air diving. 197.432 Section 197.432... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.432 Surface-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is...

  14. Diving at altitude: from definition to practice.

    PubMed

    Egi, S Murat; Pieri, Massimo; Marroni, Alessandro

    2014-01-01

    Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms.

  15. Diving at altitude: from definition to practice.

    PubMed

    Egi, S Murat; Pieri, Massimo; Marroni, Alessandro

    2014-01-01

    Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms. PMID:25562941

  16. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  17. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  18. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  19. The epidemiology of injury in scuba diving.

    PubMed

    Buzzacott, Peter L

    2012-01-01

    The epidemiology of injury associated with recreational scuba diving is reviewed. A search of electronic databases and reference lists identified pertinent research. Barotrauma, decompression sickness and drowning-related injuries were the most common morbidities associated with recreational scuba diving. The prevalence of incidents ranged from 7 to 35 injuries per 10,000 divers and from 5 to 152 injuries per 100,000 dives. Recreational scuba diving fatalities account for 0.013% of all-cause mortality aged ≥ 15 years. Drowning was the most common cause of death. Among treated injuries, recovery was complete in the majority of cases. Dive injuries were associated with diver-specific factors such as insufficient training and preexisting medical conditions. Environmental factors included air temperature and flying after diving. Dive-specific factors included loss of buoyancy control, rapid ascent and repetitive deep diving. The most common event to precede drowning was running out of gas (compressed air). Though diving injuries are relatively rare prospective, longitudinal studies are needed to quantify the effects of known risk factors and, indeed, asymptomatic injuries (e.g. brain lesions). Dive injury health economics data also remains wanting. Meanwhile, health promotion initiatives should continue to reinforce adherence to established safe diving practices such as observing depth/time limits, safety stops and conservative ascent rates. However, there is an obvious lack of evaluated diving safety interventions.

  20. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  1. Scuba diving activates vascular antioxidant system.

    PubMed

    Sureda, A; Batle, J M; Ferrer, M D; Mestre-Alfaro, A; Tur, J A; Pons, A

    2012-07-01

    The aim was to study the effects of scuba diving immersion on plasma antioxidant defenses, nitric oxide production, endothelin-1 and vascular endothelial growth factor levels. 9 male divers performed an immersion at 50 m depth for a total time of 35 min. Blood samples were obtained before diving at rest, immediately after diving, and 3 h after the diving session. Leukocyte counts, plasma 8oxoHG, malondialdehyde and nitrite levels significantly increased after recovery. Activities of lactate dehydrogenase, creatine kinase, catalase and superoxide significantly increased immediately after diving and these activities remained high after recovery. Plasma myeloperoxidase activity and protein levels and extracellular superoxide dismutase protein levels increased after 3 h. Endothelin-1 concentration significantly decreased after diving and after recovery. Vascular endothelial growth factor concentration significantly increased after diving when compared to pre-diving values, returning to initial values after recovery. Scuba diving at great depth activated the plasma antioxidant system against the oxidative stress induced by elevated pO₂ oxygen associated with hyperbaria. The decrease in endothelin-1 levels and the increase in nitric oxide synthesis could be factors that contribute to post-diving vasodilation. Diving increases vascular endothelial growth factor plasma levels which can contribute to the stimulation of tissue resistance to diving-derived oxidative damage.

  2. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  3. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Diving casualties. 146.40...

  4. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Diving casualties. 146.40...

  5. [Decompression sickness after diving and following flying].

    PubMed

    Laursen, S B; Grønfeldt, W; Jacobsen, E

    1999-07-26

    A case of delayed symptoms of decompression sickness (DCS) after diving and flying is reported. The diver presented with classical signs of type 2 DCS, probably caused by air travel 16 hours after SCUBA diving. Treatment with hyperbaric oxygen (HBO) in a decompression chamber was successful. Guidelines to prevent DCS for recreational divers who plan to fly after diving are presented.

  6. Beneficial role of exercise on scuba diving.

    PubMed

    Dujic, Zelijko; Valic, Zoran; Brubakk, Alf O

    2008-01-01

    Exercising before, during, or after diving is proscribed because of the assumption that it would increase incidence of decompression sickness. Our findings show that exercise performed in a timely fashion before diving or during decompression will reduce the number of venous gas bubbles formed. Exercise after diving did not increase the number of bubbles. Nitric oxide seems to play a protective role.

  7. A review of asthma and scuba diving.

    PubMed

    Tetzlaff, Kay; Muth, Claus M; Waldhauser, Lisa K

    2002-10-01

    An increasing number of asthmatics participate in recreational scuba diving. This activity presents unique physical and physiological challenges to the respiratory system. This review addresses the susceptibility of divers with asthma to diving accidents, acute asthmatic attacks, and long-term exacerbation of their disease. Recommendations on fitness to dive with asthma and airway hyperresponsiveness are provided.

  8. Basic medical implications of scuba diving.

    PubMed

    Crook, R A

    1977-12-01

    The rapid growth of scuba diving as a sport and the vast expansion of underwater exploration for energy has made it necessary for all physicians to become familiar with diving emergencies. The basic principles of scuba diving and related clinical implications are outlined to provide a more meaningful understanding of problems which may affect a diver.

  9. Cardiovascular responses during free-diving in the sea.

    PubMed

    Marongiu, E; Crisafulli, A; Ghiani, G; Olla, S; Roberto, S; Pinna, M; Pusceddu, M; Palazzolo, G; Sanna, I; Concu, A; Tocco, F

    2015-04-01

    Cardiac output has never been assessed during free-diving diving in the sea. Knowledge of human diving response in this setting is therefore scarce. 3 immersions were performed by 7 divers: at depths of 10 m, 20 m and 30 m. Each test consisted of 3 apnea phases: descent, static and ascent. An impedance cardiograph provided data on stroke volume, heart rate and cardiac output. Mean blood pressure, arterial O2 saturation and blood lactate values were also collected. Starting from a resting value of 4.5±1.6 L∙min(-1), cardiac output at 10 m showed an increase up to 7.1±2.2 L∙min(-1) (p<0.01) during the descent, while conditions during the static and ascent phases remained unchanged. At 20 m cardiac output values were 7.3±2.4 L∙min(-1) and 6.7(±1).2 L∙min(-1) during ascent and descent, respectively (p<0.01), and 4.3±0.9 L∙min(-1) during static phase. At 30 m cardiac output values were 6.5±1.8 L∙min(-1) and 7.5±2 L∙min(-1) during descent and ascent, respectively (p<0.01), and 4.7±2.1 L∙min(-1) during static phase. Arterial O2 saturation decreased with increasing dive depth, reaching 91.1±3.4% (p<0.001 vs. rest) upon emergence from a depth of 30 m. Blood lactate values increased to 4.1±1.2 mmol∙L(-1) at the end of the 30 m dive (p<0.001 vs. rest). Results seem to suggest that simultaneous activation of exercise and diving response could lead to an absence of cardiac output reduction aimed at an oxygen-conserving effect.

  10. Recreational technical diving part 2: decompression from deep technical dives.

    PubMed

    Doolette, David J; Mitchell, Simon J

    2013-06-01

    Technical divers perform deep, mixed-gas 'bounce' dives, which are inherently inefficient because even a short duration at the target depth results in lengthy decompression. Technical divers use decompression schedules generated from modified versions of decompression algorithms originally developed for other types of diving. Many modifications ostensibly produce shorter and/or safer decompression, but have generally been driven by anecdote. Scientific evidence relevant to many of these modifications exists, but is often difficult to locate. This review assembles and examines scientific evidence relevant to technical diving decompression practice. There is a widespread belief that bubble algorithms, which redistribute decompression in favour of deeper decompression stops, are more efficient than traditional, shallow-stop, gas-content algorithms, but recent laboratory data support the opposite view. It seems unlikely that switches from helium- to nitrogen-based breathing gases during ascent will accelerate decompression from typical technical bounce dives. However, there is evidence for a higher prevalence of neurological decompression sickness (DCS) after dives conducted breathing only helium-oxygen than those with nitrogen-oxygen. There is also weak evidence suggesting less neurological DCS occurs if helium-oxygen breathing gas is switched to air during decompression than if no switch is made. On the other hand, helium-to-nitrogen breathing gas switches are implicated in the development of inner-ear DCS arising during decompression. Inner-ear DCS is difficult to predict, but strategies to minimize the risk include adequate initial decompression, delaying helium-to-nitrogen switches until relatively shallow, and the use of the maximum safe fraction of inspired oxygen during decompression.

  11. SCUBA diving for individuals with disabilities.

    PubMed

    Cheng, Jenfu; Diamond, Martin

    2005-05-01

    Self-contained underwater breathing apparatus (SCUBA) diving has become an increasingly popular recreational activity, enjoyed by millions of individuals. There has also been a growing interest in SCUBA diving in the disabled population for rehabilitation and recreation. This review discusses medical issues relevant to individuals with disabilities who wish to participate in SCUBA diving. In addition, specialized equipment, adaptations in techniques, and additional precautions will be presented. SCUBA diving can be an enriching experience, potentially helping to improve self-image and quality of life. Knowledgeable healthcare professionals can help to guide their patients who are interested in SCUBA diving.

  12. Blood-respiratory and acid-base changes during extended diving in the bimodally respiring freshwater turtle Rheodytes leukops.

    PubMed

    Gordos, Matthew A; Franklin, Craig E; Limpus, Colin J; Wilson, Gary

    2004-05-01

    Changes in blood-gas, acid-base, and plasma-ion status were investigated in the bimodally respiring turtle, Rheodytes leukops, during prolonged dives of up to 12 h. Given that R. leukops routinely submerges for several hours, the objective of this study was to determine whether voluntarily diving turtles remain aerobic and simultaneously avoid hypercapnic conditions over increasing dive lengths. Blood PO(2), PCO(2), and pH, as well as plasma concentrations of lactate, glucose, Na(+), K(+), Cl(-), total Ca, and total Mg were determined in venous blood collected from the occipital sinus. Blood PO(2) declined significantly with dive length; however, oxy-haemoglobin saturation remained greater than 30% for all R. leukops sampled. No changes were observed in blood PCO(2), pH, [HCO(3)(-)], or plasma glucose, with increasing dive length. Despite repeated dives lasting more than 2 h, plasma lactate remained less than 3 mmol l(-1) for all R. leukops sampled, indicating the absence of anaerobiosis. Compensatory acid-base adjustments associated with anaerobiosis (e.g. declining [Cl(-)], increasing total [Ca] and [Mg]) were likewise absent, with plasma-ion concentrations remaining stable with increasing dive length. Results indicate that R. leukops utilises aquatic respiration to remain aerobic during prolonged dives, thus effectively avoiding the development of a metabolic and respiratory acidosis. PMID:15034732

  13. Circulating venous bubbles in children after diving.

    PubMed

    Lemaitre, Frederic; Carturan, Daniel; Tourney-Chollet, Claire; Gardette, Bernard

    2009-02-01

    Doppler ultrasonic detection of circulating venous bubbles after a scuba dive is a useful index of decompression safety in adults, since a relationship between bubbles and the risk of decompression sickness has been documented. No study, however, has investigated circulating venous bubbles in young recreational divers after their usual dives. The aim of this study was to determine whether these bubbles would be detected in children who performed a single dive without any modification in their diving habits. Ten young recreational divers (13.1 +/- 2.3 years) performed their usual air dive. They were Doppler-monitored 20 min before the dive (12 +/- 3 m for 26 +/- 7 min) and for 60 min after surfacing, at 20-min intervals. No circulating venous bubbles were detected after the children surfaced. The results showed that during a usual shallow diving session, venous bubbles were not detected in children.

  14. Allometry of diving capacities: ectothermy vs. endothermy.

    PubMed

    Brischoux, F; Bonnet, X; Cook, T R; Shine, R

    2008-01-01

    Body mass positively influences diving capacities in air-breathing vertebrates and has been identified as a key determinant for the evolution of diving. Our review on the relationship between body mass and dive duration (a major parameter of dive performances) encompassed for the first time a wide diversity of air-breathing vertebrates. We included a substantial number of nonavian and nonmammalian diving species belonging to various independent lineages (sea snakes, iguana, turtles and crocodiles). Our analyses suggest that the widely accepted size dependency of dive duration applies with significantly less force in ectotherms compared with endotherms; notably we failed to detect any effect of body mass in ectotherms. We hypothesize that the absence of tight physiological links between body mass and respiratory demands documented in ectotherms blurred our ability to detect the expected correlation. Further exploration of the evolution of diving physiology may well necessitate adopting novel perspectives to encompass both ectothermic and endothermic modes.

  15. Common hazards of sports diving.

    PubMed

    Steinbach, A M

    1972-07-01

    The rapidly increasing diver population may result in any physician being involved in the evaluation and treatment of injuries and disease from skin and scuba diving. The majority of treatments are symptomatic, but pulmonary embolism and decompression sickness are specific emergencies that require immediate recompression. Physicians should know the site of the nearest recompression chamber.

  16. [Scuba diving and hyperbaric medicine].

    PubMed

    Pugin, Deborah; Berney, Jean-Yves

    2009-08-19

    Scuba diving is widely practiced in Switzerland. Although rare, decompression sickness may be serious and require specialized treatment. Hyperbaric therapy has been used for a long time with beneficial effects on decompression sickness and gaseous embolism. Conversely, barotrauma does not require recompressive therapy.

  17. Common Hazards of Sports Diving

    PubMed Central

    Steinbach, Andrew M.

    1972-01-01

    The rapidly increasing diver population may result in any physician being involved in the evaluation and treatment of injuries and disease from skin and scuba diving. The majority of treatments are symptomatic, but pulmonary embolism and decompression sickness are specific emergencies that require immediate recompression. Physicians should know the site of the nearest recompression chamber. PMID:20468792

  18. Diving down the reefs? Intensive diving tourism threatens the reefs of the northern Red Sea.

    PubMed

    Hasler, Harald; Ott, Jörg A

    2008-10-01

    Intensive recreational SCUBA diving threatens coral reef ecosystems. The reefs at Dahab, South Sinai, Egypt, are among the world's most dived (>30,000 dives y(-1)). We compared frequently dived sites to sites with no or little diving. Benthic communities and condition of corals were examined by the point intercept sampling method in the reef crest zone (3m) and reef slope zone (12 m). Additionally, the abundance of corallivorous and herbivorous fish was estimated based on the visual census method. Sediments traps recorded the sedimentation rates caused by SCUBA divers. Zones subject to intensive SCUBA diving showed a significantly higher number of broken and damaged corals and significantly lower coral cover. Reef crest coral communities were significantly more affected than those of the reef slope: 95% of the broken colonies were branching ones. No effect of diving on the abundance of corallivorous and herbivorous fish was evident. At heavily used dive sites, diver-related sedimentation rates significantly decreased with increasing distance from the entrance, indicating poor buoyancy regulation at the initial phase of the dive. The results show a high negative impact of current SCUBA diving intensities on coral communities and coral condition. Corallivorous and herbivorous fishes are apparently not yet affected, but are endangered if coral cover decline continues. Reducing the number of dives per year, ecologically sustainable dive plans for individual sites, and reinforcing the environmental education of both dive guides and recreational divers are essential to conserve the ecological and the aesthetic qualities of these dive sites.

  19. Saturation meter

    DOEpatents

    Gregurech, S.

    1984-08-01

    A saturation meter for use in a pressurized water reactor plant comprising a differential pressure transducer having a first and second pressure sensing means and an alarm. The alarm is connected to the transducer and is preset to activate at a level of saturation prior to the formation of a steam void in the reactor vessel.

  20. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  1. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  2. Blood temperature profiles of diving elephant seals.

    PubMed

    Meir, Jessica U; Ponganis, Paul J

    2010-01-01

    Hypothermia-induced reductions in metabolic rate have been proposed to suppress metabolism and prolong the duration of aerobic metabolism during dives of marine mammals and birds. To determine whether core hypothermia might contribute to the repetitive long-duration dives of the northern elephant seal Mirounga angustirostris, blood temperature profiles were obtained in translocated juvenile elephant seals equipped with a thermistor and backpack recorder. Representative temperature (the y-intercept of the mean temperature vs. dive duration relationship) was 37.2 degrees C +/- 0.6 degrees C (n=3 seals) in the extradural vein, 38.1 degrees C +/- 0.7 degrees C (n = 4 seals) in the hepatic sinus, and 38.8 degrees +/- 1.6 degrees C (n = 6 deals) in the aorta. Mean temperature was significantly though weakly negatively related to dive duration in all but one seal. Mean venous temperatures of all dives of individual seals ranged between 36 degrees and 38 degrees C, while mean arterial temperatures ranged between 35 degrees and 39 degrees C. Transient decreases in venous and arterial temperatures to as low as 30 degrees -33 degrees C occurred in some dives >30 min (0.1% of dives in the study). The lack of significant core hypothermia during routine dives (10-30 min) and only a weak negative correlation of mean temperature with dive duration do not support the hypothesis that a cold-induced Q(10) effect contributes to metabolic suppression of central tissues during dives. The wide range of arterial temperatures while diving and the transient declines in temperature during long dives suggest that alterations in blood flow patterns and peripheral heat loss contribute to thermoregulation during diving.

  3. Diving and marine medicine review part II: diving diseases.

    PubMed

    Spira, A

    1999-09-01

    Diving is a high-risk sport. There are approximately between 1 to 3 million recreational scuba divers in the USA (with over a quarter-million learning scuba annually); there are about 1 million in Europe and over 50,000 in the United Kingdom. In this population 3-9 deaths/100,000 occur annually in the US alone, and those surviving diving injuries far exceeds this. Diving morbidity can be from near-drowning, from gas bubbles, from barotrauma or from environmental hazards. In reality, the most common cause of death in divers is drowning (60%), followed by pulmonary-related illnesses. The mean number of annual diving fatalities in the USA from 1970 to 1993 was 103.5 (sd 24.0) and the median was 106. This article will focus primarily upon pressure effects on the health of a diver. There are two principle ways pressure can affect us: by direct mechanical effects and by changing the partial pressures of inspired gases. Dysbarism is a general term used to describe pathology from altered environmental pressure, and has two main forms: barotrauma from the uncontrolled expansion of gas within gas-filled body compartments and decompression sickness from too rapid a return to atmospheric pressure after breathing air under increased pressures. Greater than 90% of the human body is either water or bone, which is incompressible; the areas directly affected by pressure changes thus are those that are filled with air or gas. These sites include the middle ear, the eustachian tube, the sinuses, the thorax, and the gastrointestinal tract. Air in these cavities is compressed when the ambient pressure rises because the pressure of inhaled air must equilibrate with the ambient pressure.

  4. Oral and maxillofacial aspects of diving medicine.

    PubMed

    Brandt, Matthew T

    2004-02-01

    Sport diving has witnessed explosive growth in the past decade, as 8.5 million people are certified in the United States alone. Even though scuba diving is a relatively safe sport, there are serious risks that all divers must consider. Beyond the better-known sequelae such as decompression sickness, middle ear dysfunction, and potential central nervous system effects, scuba diving also carries inherent risk to the maxillofacial region. Atypical facial pain, temporomandibular joint dysfunction, sinus barotraumas, and barodontalgia have all been reported by dentists and physicians treating military, commercial, and sport divers. Additionally, clinicians must address anatomic concerns for would-be divers, including cleft lip and palate, edentulism, or patients with pre-existing temporomandibular dysfunction, midfacial trauma, or craniomaxillofacial surgery. Health care professionals should have a thorough understanding of the implications of scuba diving for consultation and recommendation regarding diving fitness and the treatment of adverse effects of scuba diving to the maxillofacial region.

  5. Diving medicine: a review of current evidence.

    PubMed

    Lynch, James H; Bove, Alfred A

    2009-01-01

    Recreational scuba diving is a growing sport worldwide, with an estimated 4 million sport divers in the United States alone. Because divers may seek medical care for a disorder acquired in a remote location, physicians everywhere should be familiar with the physiology, injury patterns, and treatment of injuries and illnesses unique to the underwater environment. Failure to properly recognize, diagnose, and appropriately treat some diving injuries can have catastrophic results. In addition, recreational dive certification organizations require physical examinations for medical clearance to dive. This article will review both common and potentially life-threatening conditions associated with diving and will review current evidence behind fitness to dive considerations for elderly divers and those with common medical conditions.

  6. A diving fatality due to oxygen toxicity during a "technical" dive.

    PubMed

    Lawrence, C H

    1996-09-01

    An experienced diver drowned after a generalised seizure caused by oxygen toxicity during a 19-minute "technical" dive to a depth of 47 m. He had used a 50% oxygen/nitrogen gas mixture inappropriately during the dive. This case attests the risk of oxygen toxicity from oxygen-enriched air during deep dives, the shortcomings of the diver's equipment, and the need to examine, with knowledge of diving physiology and practice, both the body and equipment.

  7. Massive pneumoperitoneum after scuba diving.

    PubMed

    Oh, Seung-Tak; Kim, Wook; Jeon, Hae-Myung; Kim, Jeong-Soo; Kim, Kee-Whan; Yoo, Seung-Jin; Kim, Eung-Kuk

    2003-04-01

    Pneumoperitoneum usually indicates rupture of a hollow viscus and considered a surgical emergency. But air may also enter the peritoneum from the lung or the genital organs in female without visceral perforation. While scuba diving, the rapid ascent is usually controlled by placing in a decompression chamber and the excess gas volume is exhaled. Failure to allow this excess gas to escape will result in overdistension of air passage, which may rupture resulting in pulmonary interstitial emphysema or, if air enters the circulation, air embolus can occur. Pneumo-peritoneum is a rare complication of diving accidents. While the majority of cases are not related to an intraabdominal catastrophy, more than 20% have been the result of gastric rupture. We report a 42-yr-old male patient with massive pneumoperitoneum after scuba diving, who presented himself with dyspnea and abdominal distension. Knowledge of this rare condition and its benign course may allow the emergency physician and surgeon to order appropriate studies to help avoid unnecessary surgical treatment. It is important to determine promptly whether the air emanated from a ruptured viscus or was introduced from an extraperitoneal source. Free air in the abdomen does not always indicate a ruptured intra-abdominal viscus.

  8. Buoyancy and diving behavior in mosquito pupae.

    PubMed

    Romoser, W S; Lucas, E A

    1999-06-01

    Mosquito pupal diving behavior has been studied mostly in Aedes aegypti and in this species pupal buoyancy varies relative to several factors. The research reported herein addresses the 2 following questions. Does diving behavior vary among different mosquito genera and species? How is diving behavior influenced by variation in buoyancy? Depth and duration of dive, and dive pattern, were compared among Ae. aegypti, Culex pipiens, Anopheles stephensi, Aedes albopictus, and Aedes triseriatus. In response to the stimulation associated with transferring pupae between containers, diving behavior varied dramatically among the different genera studied. Culex pipiens and An. stephensi make short-duration, shallow dives and remain positively buoyant. The 3 aedine species studied make longer-duration dives, typically to a depth at which they become neutrally or negatively buoyant. Buoyancy reduction effects were studied in the 3 aedine species. Normally buoyant pupae tend to dive to greater depths and for longer periods of time than reduced-buoyancy pupae. Aedine pupal diving behavior clearly is closely regulated relative to buoyancy variation. To the earlier hypotheses that pupal behavior may help avoid predation and be energy-conserving, we add the suggestion that the diving behavior displayed by the container-breeding aedine pupae we studied represents an adaptation that helps keep them from being washed from their container habitat by overflowing water during rainfall. We also suggest that the diving behavior of all the species studied may help pupae survive heavy, pelting rainfall by enabling them to avoid the mechanical shock of a direct hit by a raindrop, which could cause disruption of the gas in the ventral air space, thereby causing the loss of hydrostatic balance and drowning.

  9. Extreme human breath-hold diving.

    PubMed

    Ferretti, G

    2001-04-01

    In this paper, the respiratory, circulatory and metabolic adjustments to human extreme breath-hold diving are reviewed. A survey of the literature reveals that in extreme divers, adaptive mechanisms take place that allow prolongation of apnoea beyond the limits attained by non-diving subjects, and preservation of oxygen stores during the dives. The occurrence of a diving response, including peripheral vasoconstriction, increased arterial blood pressure, bradycardia and lowered cardiac output, is strongly implicated. Some peripheral regions may be excluded from perfusion, with consequent reliance on anaerobic metabolism. In addition, extreme breath-hold divers show a blunted ventilatory response to carbon dioxide breathing, possibly as a consequence of frequent exposure to high carbon dioxide partial pressures during the dives. These mechanisms allow the attainment of particularly low alveolar oxygen (< 30 mmHg) and high alveolar carbon dioxide (> 50 mmHg) partial pressures at the end of maximal dry breath-holds, and reduce oxygen consumption during the dive at the expense of increased anaerobic glycolysis (rate of blood lactate accumulation > 0.04 mM.s-1). The current absolute world record for depth in breath-hold diving is 150 m. Its further improvement depends upon how far the equilibrium between starting oxygen stores, the overall rate of energy expenditure, the fraction of energy provided by anaerobic metabolism and the diving speed can be pushed, with consciousness upon emersion. The ultimate limit to breath-hold diving records may indeed be imposed by an energetic constraint. PMID:11374109

  10. Shallow Water Diving - The NASA Experience

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Daniel; Kelsey-Seybold

    2010-01-01

    This slide presentation reviews some of the problems and solutions that personnel have experienced during sessions in the Neutral Bu0yancy Lab (NBL). It reviews the standard dive that occurs at the NBL, Boyles and Henry's laws as they relate to the effects of diving. It then reviews in depth some of the major adverse physiologic events that happen during a diving session: Ear and Sinus Barotrauma, Decompression Sickness, (DCS), Pulmonary Barotrauma (i.e., Arterial Gas Embolism (AGE). Mediastinal Emphysema, Subcutaneous Emphysema, and Pneumothorax) Oxygen Toxicity and Hypothermia. It includes information about the pulmonary function in NBL divers. Also included is recommendations about flying after diving.

  11. Diving medicine: contemporary topics and their controversies.

    PubMed

    Strauss, M B; Borer, R C

    2001-05-01

    SCUBA diving is a popular recreational sport. Although serious injuries occur infrequently, when they do knowledge of diving medicine and/or where to obtain appropriate consultation is essential. The emergency physician is likely to be the first physician contact the injured diver has. We discuss 8 subjects in diving medicine which are contemporary, yet may have controversies associated with them. From this information the physician dealing primarily with the injured diver will have a basis for understanding and managing, as well as where to find additional help, for his/her patients' diving injuries.

  12. Ultrasonic evidence of acute interstitial lung edema after SCUBA diving is resolved within 2-3h.

    PubMed

    Ljubkovic, Marko; Gaustad, Svein Erik; Marinovic, Jasna; Obad, Ante; Ivancev, Vladimir; Bilopavlovic, Nada; Breskovic, Toni; Wisloff, Ulrik; Brubakk, Alf; Dujic, Zeljko

    2010-04-30

    Recently, an increase in extravascular lung water (EVLW) accumulation with diminished left ventricular contractility within 60 min after SCUBA diving was reported. We have observed previously that diving was associated with reduced diffusing lung capacity for carbon monoxide (DLCO) and arterial oxygen pressure for up to 60-80 min postdive. Here we investigated whether increased EVLW persists 2-3h after successive deep dives in a group of seven male divers. The echocardiographic indices of pulmonary water accumulation (ultrasound lung comets (ULC)) and left ventricular function, respiratory functional measurements and arterial oxygen saturation (SaO(2)) were assessed 2-3h post diving, while venous gas bubbles (VGB) and the blood levels of NT-proBNP and proANP were analyzed 40 min after surfacing. Spirometry values, flow-volume, DLCO, SaO(2) and ULC were unchanged after each dive, except for significant increase in ULC after the second dive. Left ventricular function was reduced, while NT-proBNP and proANP levels were significantly elevated after majority of dives, suggesting a cardiac strain.

  13. Can diving-induced tissue nitrogen supersaturation increase the chance of acoustically driven bubble growth in marine mammals?

    PubMed

    Houser, D S; Howard, R; Ridgway, S

    2001-11-21

    The potential for acoustically mediated causes of stranding in cetaceans (whales and dolphins) is of increasing concern given recent stranding events associated with anthropogenic acoustic activity. We examine a potentially debilitating non-auditory mechanism called rectified diffusion. Rectified diffusion causes gas bubble growth, which in an insonified animal may produce emboli, tissue separation and high, localized pressure in nervous tissue. Using the results of a dolphin dive study and a model of rectified diffusion for low-frequency exposure, we demonstrate that the diving behavior of cetaceans prior to an intense acoustic exposure may increase the chance of rectified diffusion. Specifically, deep diving and slow ascent/descent speed contributes to increased gas-tissue saturation, a condition that amplifies the likelihood of rectified diffusion. The depth of lung collapse limits nitrogen uptake per dive and the surface interval duration influences the amount of nitrogen washout from tissues between dives. Model results suggest that low-frequency rectified diffusion models need to be advanced, that the diving behavior of marine mammals of concern needs to be investigated to identify at-risk animals, and that more intensive studies of gas dynamics within diving marine mammals should be undertaken.

  14. Can diving-induced tissue nitrogen supersaturation increase the chance of acoustically driven bubble growth in marine mammals?

    PubMed

    Houser, D S; Howard, R; Ridgway, S

    2001-11-21

    The potential for acoustically mediated causes of stranding in cetaceans (whales and dolphins) is of increasing concern given recent stranding events associated with anthropogenic acoustic activity. We examine a potentially debilitating non-auditory mechanism called rectified diffusion. Rectified diffusion causes gas bubble growth, which in an insonified animal may produce emboli, tissue separation and high, localized pressure in nervous tissue. Using the results of a dolphin dive study and a model of rectified diffusion for low-frequency exposure, we demonstrate that the diving behavior of cetaceans prior to an intense acoustic exposure may increase the chance of rectified diffusion. Specifically, deep diving and slow ascent/descent speed contributes to increased gas-tissue saturation, a condition that amplifies the likelihood of rectified diffusion. The depth of lung collapse limits nitrogen uptake per dive and the surface interval duration influences the amount of nitrogen washout from tissues between dives. Model results suggest that low-frequency rectified diffusion models need to be advanced, that the diving behavior of marine mammals of concern needs to be investigated to identify at-risk animals, and that more intensive studies of gas dynamics within diving marine mammals should be undertaken. PMID:11894990

  15. 17 CFR 240.14d-8 - Exemption from statutory pro rata requirements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... rata requirements. 240.14d-8 Section 240.14d-8 Commodity and Securities Exchanges SECURITIES AND... rata requirements. Notwithstanding the pro rata provisions of section 14(d)(6) of the Act, if any... taken up and paid for as nearly as may be pro rata, disregarding fractions, according to the number...

  16. 17 CFR 240.14d-4 - Dissemination of tender offers to security holders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... to security holders. 240.14d-4 Section 240.14d-4 Commodity and Securities Exchanges SECURITIES AND... offers to security holders. As soon as practicable on the date of commencement of a tender offer, the bidder must publish, send or give the disclosure required by § 240.14d-6 to security holders of the...

  17. Diving the wreck: risk and injury in sport scuba diving.

    PubMed

    Hunt, J C

    1996-07-01

    This paper utilizes psychoanalytic theory to examine risk and injury in the case of a male deep sea diver. It examines the unconscious conflicts which appeared to fuel the diver's involvement in deep diving and to lead to a near fatal incident of decompression sickness. Particular attention is paid to the role of the diver's father in the evolution of the preoedipal and oedipal fantasies and conflicts which appear to be linked to the injury. The research is based on interviews with and fieldwork among recreational and deep divers.

  18. Extreme hypoxemic tolerance and blood oxygen depletion in diving elephant seals.

    PubMed

    Meir, Jessica U; Champagne, Cory D; Costa, Daniel P; Williams, Cassondra L; Ponganis, Paul J

    2009-10-01

    Species that maintain aerobic metabolism when the oxygen (O(2)) supply is limited represent ideal models to examine the mechanisms underlying tolerance to hypoxia. The repetitive, long dives of northern elephant seals (Mirounga angustirostris) have remained a physiological enigma as O(2) stores appear inadequate to maintain aerobic metabolism. We evaluated hypoxemic tolerance and blood O(2) depletion by 1) measuring arterial and venous O(2) partial pressure (Po(2)) during dives with a Po(2)/temperature recorder on elephant seals, 2) characterizing the O(2)-hemoglobin (O(2)-Hb) dissociation curve of this species, 3) applying the dissociation curve to Po(2) profiles to obtain %Hb saturation (So(2)), and 4) calculating blood O(2) store depletion during diving. Optimization of O(2) stores was achieved by high venous O(2) loading and almost complete depletion of blood O(2) stores during dives, with net O(2) content depletion values up to 91% (arterial) and 100% (venous). In routine dives (>10 min) Pv(O(2)) and Pa(O(2)) values reached 2-10 and 12-23 mmHg, respectively. This corresponds to So(2) of 1-26% and O(2) contents of 0.3 (venous) and 2.7 ml O(2)/dl blood (arterial), demonstrating remarkable hypoxemic tolerance as Pa(O(2)) is nearly equivalent to the arterial hypoxemic threshold of seals. The contribution of the blood O(2) store alone to metabolic rate was nearly equivalent to resting metabolic rate, and mean temperature remained near 37 degrees C. These data suggest that elephant seals routinely tolerate extreme hypoxemia during dives to completely utilize the blood O(2) store and maximize aerobic dive duration.

  19. Introduction to Scuba Diving. Diver Education Series.

    ERIC Educational Resources Information Center

    Somers, Lee H.

    Scuba diving is often referred to as a "recreational sport." However, the term "sport" sometimes implies erroneous connotations and limits understanding. Scuba diving can be an avocation or a vocation. It is a pastime, a pursuit, or even a lifestyle, that can be as limited or extensive as one makes it. A persons level of commitment, degree of…

  20. Teaching Persons with Disabilities to SCUBA Diving.

    ERIC Educational Resources Information Center

    Jankowski, Louis W.

    This booklet is designed to sensitize and inform the scuba diving instructor on appropriate attitudes and successful methods for teaching scuba diving to persons with physical disability. It addresses misconceptions about people with disabilities and the importance of effective two-way communication and mutual respect between instructors and…

  1. Wind-Tunnel Investigations of Diving Brakes

    NASA Technical Reports Server (NTRS)

    Fucha, D.

    1942-01-01

    Unduly high diving speeds can be effectively controlled by diving brakes but their employment involves at the same time a number of disagreeable features: namely, rotation of zero lift direction, variation of diviving moment, and, the creation of a potent dead air region.

  2. Scuba diving: how high the risk?

    PubMed

    Smith, N

    1995-01-01

    The host factors that represent the most risk for scuba-diving safety are poor fitness, overweight, chronic diseases, structural abnormalities of the heart and lungs, and multiple risk factors for CAD. Any of these factors, plus inexperience, a history of irresponsible behavior, or participation in technical diving should alert medical underwriting that a scuba diver has excess risk for fatal accidents.

  3. Orbital fracture deterioration after scuba diving.

    PubMed

    Nakatani, Hiroko; Yoshioka, Nobutaka

    2009-07-01

    Sinus barotrauma is a common disease in divers. However, it is not familiar to maxillofacial surgeon. We presented orbital fracture deterioration by sinus barotrauma in scuba diving and a review of literatures. We also discussed the clinical features, the prevention, and the possible mechanism of orbital fracture deterioration after scuba diving.

  4. [Children and scuba diving. How to start?].

    PubMed

    Panchard, Marc-Alain

    2002-12-01

    Contra-indications to scuba diving are now well defined. The number of children practicising this sport is increasing. However, no consensus nor prospective study exists that allows to determine an age under which physicians should advise against scuba diving. This paper reviews many different approaches and, considering physiopathology and intellecual development, suggests a practical attitude.

  5. [Scuba diving: risks for whom and why?].

    PubMed

    Heymans, O; Wuilmart, M; Gielen, J L

    2001-04-01

    Scuba diving is an occupation with a still growing expansion. Like every sport it has its own specific pathologies. Some accidents can be very serious and life-threatening. We discuss the 3 main groups of accidents: barotraumatism, gas toxicity and accidents related to aquatic environment. The knowledge of the mechanisms underlying these accidents leads to a less risky approach of scuba diving.

  6. How to keep scuba diving safe.

    PubMed

    Everhart-McDonald, M A

    2000-05-01

    As scuba diving grows in popularity, divers must know the safety factors involved. For example, they need to know their abilities and how to dive within those limits, how to react to emergency situations, and how to prevent and treat common medical conditions. Below are clear answers to common questions.

  7. Haematology studies during a 350-metre dive.

    PubMed

    Paciorek, J A; Rolfsen, T

    1986-04-01

    Routine haematological monitoring of 6 deep-sea divers was performed pre-dive, during the three phases of the 350 m working dive, and at two post-dive medical examinations. In the compression phase a small percentage (less than 5%) of each subject's red cells became non-discoid in shape and this trend continued during the 6 d at 350 m. Concomitantly each subject was mildly dehydrated by compression diuresis and had a raised haematocrit (+5%); all other haematological parameters remained within normal limits. The number of morphologically aberrant cells continued to increase during decompression but were not present at the 1 month post-dive medical examination. The subjects' mean relative reticulocyte number was decreased during the dive to 0.4%, showing a rapid and sustained increase to 2.1% at both post-dive examinations. The red cell count was reduced by 10% during the course of the dive. Hb concentration and haematocrit evidenced no differences between the pre- or post-dive measurements.

  8. Predicting performance in competitive apnea diving. Part III: deep diving.

    PubMed

    Schagatay, Erika

    2011-12-01

    The first of these reviews described the physiological factors defining the limits of static apnea, while the second examined performance in apneic distance swimming. This paper reviews the factors determining performance in depth disciplines, where hydrostatic pressure is added to the stressors associated with apnea duration and physical work. Apneic duration is essential for performance in all disciplines, and is prolonged by any means that increases gas storage or tolerance to asphyxia or reduces metabolic rate. For underwater distance swimming, the main challenge is to restrict metabolism despite the work of swimming, and to redirect blood flow to allow the most vital functions. Here, work economy, local tissue energy and oxygen stores, anaerobic capacity of the muscles, and possibly technical improvements will be essential for further development. In the depth disciplines, direct pressure effects causing barotrauma, the narcotic effects of gases, decompression sickness (DCS) and possibly air embolism during ascent need to be taken into account, as does the risk of hypoxia when the dive cannot be rapidly interrupted before the surface is reached again. While in most deep divers apneic duration is not the main limitation thus far, greater depths may call for exceptionally long apneas and slower ascents to avoid DCS. Narcotic effects may also affect the ultimate depth limit, which the divers currently performing 'constant weight with fins' dives predict to be around 156 metres' sea water. To reach these depths, serious physiological challenges have to be met, technical developments needed and safety procedures developed concomitantly.

  9. Advanced deep sea diving equipment

    NASA Technical Reports Server (NTRS)

    Danesi, W. A.

    1972-01-01

    Design requirements are generated for a deep sea heavy duty diving system to equip salvage divers with equipment and tools that permit work of the same quality and in times approaching that done on the surface. The system consists of a helmet, a recirculator for removing carbon dioxide, and the diver's dress. The diver controls the inlet flow by the recirculatory control valve and is able to change closed cycle operation to open cycle if malfunction occurs. Proper function of the scrubber in the recirculator minimizes temperature and humidity effects as it filters the returning air.

  10. [Medical aspects of diving in the tropics].

    PubMed

    Muth, C M; Müller, P; Kemmer, A

    2005-07-01

    Scuba diving vacations in tropical surroundings belong to the repertoire of most divers. In addition to carefully making travel plans and taking care of the necessary vaccinations and appropriate malaria prophylaxis, the following points also must be observed. The flight itself affects diving safety. In particular, a too short time interval between diving and the return flight can lead to decompression problems. Because most of the diving areas are reached by ship, many divers need a prophylaxis against motion sickness. Moreover, external otitis occurs more frequently while diving in the tropics. Finally, there is potential danger from the sea inhabitants, primarily from scorpion fishes, Portuguese Man-of-Wars, box jellyfishes as well as cone snails.

  11. The cardiovascular system and diving risk.

    PubMed

    Bove, Alfred A

    2011-01-01

    Recreational scuba diving is a sport that requires a certain physical capacity, in addition to consideration of the environmental stresses produced by increased pressure, low temperature and inert gas kinetics in tissues of the body. Factors that may influence ability to dive safely include age, physical conditioning, tolerance of cold, ability to compensate for central fluid shifts induced by water immersion, and ability to manage exercise demands when heart disease might compromise exercise capacity. Patients with coronary heart disease, valvular heart disease, congenital heart disease and cardiac arrhythmias are capable of diving, but consideration must be given to the environmental factors that might interact with the cardiac disorder. Understanding of the interaction of the diving environment with various cardiac disorders is essential to providing a safe diving environment to individual divers with known heart disease.

  12. The cardiovascular system and diving risk.

    PubMed

    Bove, Alfred A

    2011-01-01

    Recreational scuba diving is a sport that requires a certain physical capacity, in addition to consideration of the environmental stresses produced by increased pressure, low temperature and inert gas kinetics in tissues of the body. Factors that may influence ability to dive safely include age, physical conditioning, tolerance of cold, ability to compensate for central fluid shifts induced by water immersion, and ability to manage exercise demands when heart disease might compromise exercise capacity. Patients with coronary heart disease, valvular heart disease, congenital heart disease and cardiac arrhythmias are capable of diving, but consideration must be given to the environmental factors that might interact with the cardiac disorder. Understanding of the interaction of the diving environment with various cardiac disorders is essential to providing a safe diving environment to individual divers with known heart disease. PMID:21877555

  13. [Medical aspects of diving in the tropics].

    PubMed

    Muth, C M; Müller, P; Kemmer, A

    2005-07-01

    Scuba diving vacations in tropical surroundings belong to the repertoire of most divers. In addition to carefully making travel plans and taking care of the necessary vaccinations and appropriate malaria prophylaxis, the following points also must be observed. The flight itself affects diving safety. In particular, a too short time interval between diving and the return flight can lead to decompression problems. Because most of the diving areas are reached by ship, many divers need a prophylaxis against motion sickness. Moreover, external otitis occurs more frequently while diving in the tropics. Finally, there is potential danger from the sea inhabitants, primarily from scorpion fishes, Portuguese Man-of-Wars, box jellyfishes as well as cone snails. PMID:16041936

  14. Cormorants dive through the Polar night

    PubMed Central

    Grémillet, David; Kuntz, Grégoire; Gilbert, Caroline; Woakes, Antony J; Butler, Patrick J; le Maho, Yvon

    2005-01-01

    Most seabirds are visual hunters and are thus strongly affected by light levels. Dependence on vision should be problematic for species wintering at high latitudes, as they face very low light levels for extended periods during the Polar night. We examined the foraging rhythms of male great cormorants (Phalacrocorax carbo) wintering north of the Polar circle in West Greenland, conducting the first year-round recordings of the diving activity in a seabird wintering at high latitudes. Dive depth data revealed that birds dived every day during the Arctic winter and did not adjust their foraging rhythms to varying day length. Therefore, a significant proportion of the dive bouts were conducted in the dark (less than 1 lux) during the Polar night. Our study underlines the stunning adaptability of great cormorants and raises questions about the capacity of diving birds to use non-visual cues to target fish. PMID:17148235

  15. Probability of decompression sickness in no-stop air diving and subsaturation diving.

    PubMed

    Van Liew, H D; Flynn, E T

    2005-01-01

    Probabilistic models allow estimation of the probability (Pdcs) that decompression sickness (DCS) will occur in any particular dive. Our objective is to provide Pdcs estimates for no-stop diving instructions used by the U.S. Navy and various other navies. To do so, we develop statistics-based (probabilistic) and intuition-based (deterministic) models using dive-outcome data from the U.S. Navy Decompression Database. We give special attention to subsaturation dives (defined as no-stop dives shallower than 40 fswg with bottom times between 4 hr and one day), for which experimental dives are scarce. According to our models, probability of DCS is 2% or less for current U.S. Navy no-stop air dive schedules and near 1% for the navies of Great Britain, Canada, and France; also the current U.S. Navy prescriptions for subsaturation dives seem to be appropriate. Our probabilistic models fail for deep dives; they do not avoid observed DCS cases in the calibration dataset and provide longer no-stop times than allowed by tables used operationally; we advocate prescriptions by our deterministic model for deep no-stop dives.

  16. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  17. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.426 Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the...

  18. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  19. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  20. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Surface-supplied air diving. 197.432 Section 197.432...-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is conducted... space; and (f) The surface-supplied air diver has the equipment required by § 197.346 (b) or (d)....

  1. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the following requirements, unless otherwise specified. (b) Limits. Mixed-gas diving shall be conducted only when: (1)...

  2. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the following requirements, unless otherwise specified. (b) Limits. Mixed-gas diving shall be conducted only when: (1)...

  3. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with...

  4. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the following requirements, unless otherwise specified. (b) Limits. Mixed-gas diving shall be conducted only when: (1)...

  5. Adrenal gland denervation and diving in ducks.

    PubMed

    Mangalam, H J; Jones, D R; Lacombe, A M

    1987-06-01

    The extreme elevation in plasma levels of free norepinephrine (NE) and free epinephrine (EP), which occurs during forced diving of ducks (Anas platyrhynchos), was studied before and after denervation of the adrenal glands. In intact animals both NE and EP concentration increased by up to two orders of magnitude in a 4-min dive but by a significantly lesser amount if the duck breathed O2 before the dive. Denervating the adrenal glands reduced the amounts of both catecholamines (CA) released during dives, plasma EP decreased to 10%, and NE to 50% of values obtained before denervation. Breathing O2 before a dive virtually eliminated CA release in denervates, indicating that hypoxia was the important non-neural releasing agent. Hypoxia was also the most important neural releasing agent compared with hypercapnia, acidosis, or hypoglycemia. Adrenal denervation did not cause significant changes in heart rate, blood pressure, arterial blood gas tensions, pH, or plasma glucose during dives, although denervation caused increased variation in some of these variables. In ducks CA release in dives is largely due to decreasing arterial O2 partial pressure, and full expression of the response is dependent on intact innervation of the adrenal gland. PMID:3591985

  6. Rapid brain cooling in diving ducks.

    PubMed

    Caputa, M; Folkow, L; Blix, A S

    1998-08-01

    Hypothermia may limit asphyxic damages to the brain, and many small homeotherms have been shown to use anapyrexic strategies when exposed to asphyxic conditions. Larger homeotherms do not seem to use the same strategy, but could save oxygen and prevent hypoxic brain damage by employing selective brain cooling (SBC) in connection with asphyxia. To test the hypothesis that selective brain cooling may take place in connection with asphyxia, we have recorded brain [hypothalamic (THyp)] and body [colonic (TC)] temperatures and heart rates in four Pekin ducks during 5-min simulated (head submersion) diving in cold water (10 degrees C). Diving resulted in a drop in THyp (3.1 +/- 1.4 degrees C) that continued into the recovery period (P < 0.001). Restricting heat loss from the buccal cavity and eyes during diving compromised brain cooling in an additive manner. TC was not influenced by diving. Control cooling of the head with crushed ice during a 5-min period of undisturbed breathing had no effect on THyp. Warm water (35 degrees C) markedly reduced brain cooling, and dive capacity was reduced by approximately 14% (P < 0.05) compared with diving in water at 10 degrees C. The data suggest that SBC is used in ducks during diving, and we propose that this mechanism may enable the bird to save oxygen for prolonged aerobic submergence and to protect the brain from asphyxic damages. PMID:9688670

  7. Heart rate regulation and extreme bradycardia in diving emperor penguins.

    PubMed

    Meir, Jessica U; Stockard, Torre K; Williams, Cassondra L; Ponganis, Katherine V; Ponganis, Paul J

    2008-04-01

    To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly diving [dive f(H) (total beats/duration)=57+/-2 beats min(-1), f(H) at rest=73+/-2 beats min(-1) (mean +/- s.e.m.)]. For dives less than the aerobic dive limit (ADL; duration beyond which [blood lactate] increases above resting levels), dive f(H)=85+/-3 beats min(-1), whereas f(H) in dives greater than the ADL was significantly lower (41+/-1 beats min(-1)). In dives greater than the ADL, f(H) reached extremely low values: f(H) during the last 5 mins of an 18 min dive was 6 beats min(-1). Dive f(H) and minimum instantaneous f(H) during dives declined significantly with increasing dive duration. Dive f(H) was independent of swim stroke frequency. This suggests that progressive bradycardia and peripheral vasoconstriction (including isolation of muscle) are primary determinants of blood oxygen depletion in diving emperor penguins. Maximum instantaneous surface interval f(H) in this study is the highest ever recorded for emperor penguins (256 beats min(-1)), equivalent to f(H) at V(O(2)) max., presumably facilitating oxygen loading and post-dive metabolism. The classic Scholander-Irving dive response in these emperor penguins contrasts with the absence of true bradycardia in diving ducks, cormorants, and other penguin species. PMID:18375841

  8. Diving energetics in king penguins (Aptenodytes patagonicus).

    PubMed

    Culik, B M; Pütz, K; Wilson, R P; Allers, D; Lage, J; Bost, C A; Le Maho, Y

    1996-04-01

    Dive duration in wild king penguins and the energetic cost of swimming in a 30m long swim channel were determined at Ile de la Possession, Crozet Archipelago, using external data loggers and respirometry, respectively. Calibrated electronic data loggers equipped with a pressure sensor were used to determine dive durations: 95% of dives were less than 6 min long and 66% of dives were less than 4 min long. Dive patterns show that king penguins may intersperse long dive durations (4-6.3 min) with short ones (1.5-3 min) and make surface pauses of variable duration between them (0.5-3.5 min), or dive regularly (for up to 5 h) with long dive durations (5 min) and constant interdive surface intervals (1.5 min). The latter indicates that the aerobic dive limits (ADL) of this species could be higher and oxygen consumption lower than previously reported. Assuming that king penguins dive within their aerobic limit, different approaches to the analysis of the data obtained in the swim channel are discussed to derive the ADL. Swimming speeds observed in the channel ranged from 0.9 to 3.4 m s-1. Transport costs were lowest between 1.8 and 2.2 m s-1. Although at 2.2 m s-1 king penguins used only 10.3 Wkg-1 over a dive+surface cycle (minimal transport costs of 4.7 J kg-1 m-1), we speculate that tisse oxygen consumption during submergence may be as low as 0.23 ml O2 kg-1 s-1 (2.1 times standard metabolic rate, SMR) or perhaps lower (which gives an ADL of 4.2 min). During surface phases, oxygen uptake would be increased to at least 1 ml O2kg-1 s-1 (9.3 times SMR). This implies that at least 70% of all dives are aerobic. Potential physiological mechanisms allowing king penguins to partition O2 consumption between submergence and surface periods remain, however, unclear. PMID:8788090

  9. Decompression Sickness in Sport Scuba Diving.

    PubMed

    Davis, J C; Bracker, M D

    1988-02-01

    In brief: Sport scuba diving in inland bodies of water has gained in popularity, and travelers to remote areas can fly home soon after a diving trip. Thus it is not unusual to see a case of decompression sickness in an emergency care facility, regardless of its location. Symptoms of decompression sickness may occur minutes or hours after diving with compressed gas. They include marked fatigue, pruritic mottled skin lesions, pain (joints, back, abdomen), weakness or paralysis of isolated or regional muscle groups, paresthesia, urinary retention, loss of anal sphincter control, dyspnea, coughing, vertigo, and substernal pain. Most patients respond quickly to prompt treatment in hyperbaric chambers, and the symptoms resolve completely.

  10. [Diving medicine aspects in otorhinolaryngology. II. Diving-specific illnesses and dysfunctions as well as assessment for diving fitness].

    PubMed

    Dieler, R; Shehata-Dieler, W E

    2001-01-01

    Scuba diving with compressed air has become a recreational sport that can be performed at all stages of adulthood. The human body including all gas-filled cavities are exposed to an increased ambient pressure during a dive. In the present review article, specific aspects of diving related disorders are that are of importance in the otolaryngology field are presented and discussed: the multitude of causes for divers' vertigo and the so called divers ear. Furthermore, useful recommendations in the assessment of physical fitness for diving are presented. This review will provide a background and foundation for both, an adequate treatment of these diseases and a critical and responsible health education of the diver.

  11. Diving injuries: a preventable catastrophe.

    PubMed

    Kluger, Y; Jarosz, D; Paul, D B; Townsend, R N; Diamond, D L

    1994-03-01

    During a 5-year period from January 1987 through January 1992, 58 patients were admitted to the Allegheny General Hospital trauma center for non-scuba, non-suicidal diving injuries. There were 46 men and 12 women (mean age, 23 years). Forty-five patients were injured in swimming pools. Twenty-two patients had blood alcohol levels > 100 mg/dL. Cervical spine injury was the most common pathologic entity encountered in this group of patients. Closed head injury, pelvic fracture, thoracic vertebral fracture, and rib fractures were other injuries identified. Some patients had multiple organ failure syndrome. Aquatic recreational activities carry a risk for injury that is preventable. The mechanism, clinical data, and complications of 58 patients are presented and the importance of prevention is discussed.

  12. Distributed Saturation

    NASA Technical Reports Server (NTRS)

    Chung, Ming-Ying; Ciardo, Gianfranco; Siminiceanu, Radu I.

    2007-01-01

    The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive veri cation of complex systems, in particular globally-asyn- chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo- rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache policies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme and several operation cache policies to help on solving extremely complex systems. Experiments show that our schemes improve the performance of the original distributed implementation, SmArTNow, in terms of time and memory efficiency.

  13. Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry.

    PubMed

    Roche, Ronan C; Harvey, Chloe V; Harvey, James J; Kavanagh, Alan P; McDonald, Meaghan; Stein-Rostaing, Vivienne R; Turner, John R

    2016-07-01

    Recreational diving on coral reefs is an activity that has experienced rapidly growing levels of popularity and participation. Despite providing economic activity for many developing coastal communities, the potential role of dive impacts in contributing to coral reef damage is a concern at heavily dived locations. Management measures to address this issue increasingly include the introduction of programmes designed to encourage environmentally responsible practices within the dive industry. We examined diver behaviour at several important coral reef dive locations within the Philippines and assessed how diver characteristics and dive operator compliance with an environmentally responsible diving programme, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size. Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive, with a mean (±SE) contact rate of 0.12 ± 0.01 per min. We found evidence that the ability of dive guides to intervene and correct diver behaviour in the event of a reef contact decreases with larger diver group sizes. Divers from operators with high levels of compliance with the Green Fins programme exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance. The successful implementation of environmentally responsible diving programmes, which focus on influencing dive industry operations, can contribute to the management of human impacts on coral reefs.

  14. Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry.

    PubMed

    Roche, Ronan C; Harvey, Chloe V; Harvey, James J; Kavanagh, Alan P; McDonald, Meaghan; Stein-Rostaing, Vivienne R; Turner, John R

    2016-07-01

    Recreational diving on coral reefs is an activity that has experienced rapidly growing levels of popularity and participation. Despite providing economic activity for many developing coastal communities, the potential role of dive impacts in contributing to coral reef damage is a concern at heavily dived locations. Management measures to address this issue increasingly include the introduction of programmes designed to encourage environmentally responsible practices within the dive industry. We examined diver behaviour at several important coral reef dive locations within the Philippines and assessed how diver characteristics and dive operator compliance with an environmentally responsible diving programme, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size. Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive, with a mean (±SE) contact rate of 0.12 ± 0.01 per min. We found evidence that the ability of dive guides to intervene and correct diver behaviour in the event of a reef contact decreases with larger diver group sizes. Divers from operators with high levels of compliance with the Green Fins programme exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance. The successful implementation of environmentally responsible diving programmes, which focus on influencing dive industry operations, can contribute to the management of human impacts on coral reefs. PMID:27055531

  15. Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry

    NASA Astrophysics Data System (ADS)

    Roche, Ronan C.; Harvey, Chloe V.; Harvey, James J.; Kavanagh, Alan P.; McDonald, Meaghan; Stein-Rostaing, Vivienne R.; Turner, John R.

    2016-07-01

    Recreational diving on coral reefs is an activity that has experienced rapidly growing levels of popularity and participation. Despite providing economic activity for many developing coastal communities, the potential role of dive impacts in contributing to coral reef damage is a concern at heavily dived locations. Management measures to address this issue increasingly include the introduction of programmes designed to encourage environmentally responsible practices within the dive industry. We examined diver behaviour at several important coral reef dive locations within the Philippines and assessed how diver characteristics and dive operator compliance with an environmentally responsible diving programme, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size. Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive, with a mean (±SE) contact rate of 0.12 ± 0.01 per min. We found evidence that the ability of dive guides to intervene and correct diver behaviour in the event of a reef contact decreases with larger diver group sizes. Divers from operators with high levels of compliance with the Green Fins programme exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance. The successful implementation of environmentally responsible diving programmes, which focus on influencing dive industry operations, can contribute to the management of human impacts on coral reefs.

  16. Facial baroparesis caused by scuba diving.

    PubMed

    Kamide, Daisuke; Matsunobu, Takeshi; Shiotani, Akihiro

    2012-01-01

    Middle ear barotrauma is one of the common complications of SCUBA diving representing acute otalgia, hearing loss, and bleeding. But occurrence of facial palsy is rare. Here we report a case of a 30-year-old navy diver suffered middle ear barotrauma with transient facial palsy after SCUBA diving. He felt difficulty in equalizing the pressure in middle ear with Valsalva maneuver during diving, and suffered right facial palsy and aural fullness after diving. Clinical examination showed remarkable bulging of the right tympanic membrane and right facial palsy without other neurological findings. But facial palsy was disappeared immediately after myringotomy. We considered that the etiology of this case was neuropraxia of facial nerve in middle ear caused by over pressure of middle ear.

  17. Temporal bone pathology in scuba diving deaths.

    PubMed

    Antonelli, P J; Parell, G J; Becker, G D; Paparella, M M

    1993-09-01

    Scuba diving has long been associated with otologic injuries; however, little is known about temporal bone pathology in diving-related deaths. We examined 18 temporal bones from 11 divers who died, primarily from complications of rapid ascent. Bleeding into the middle ear and mastoid air cells was nearly universal. Inner ear damage included hemorrhage around Reissner's membrane and the round window membrane and rupture of the utricle and saccule. Most of the observed inner ear damage was not surgically treatable.

  18. Decompression sickness following breath-hold diving.

    PubMed

    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  19. SCUBA Diving and Asthma: Clinical Recommendations and Safety.

    PubMed

    Coop, Christopher A; Adams, Karla E; Webb, Charles N

    2016-02-01

    The objective of this article is to review the available studies regarding asthma and SCUBA (self-contained underwater breathing apparatus) diving. A literature search was conducted in MEDLINE to identify peer-reviewed articles related to asthma and SCUBA diving using the following keywords: asthma, allergy, and SCUBA diving. SCUBA diving is a popular sport with more than 9 million divers in the USA. SCUBA diving can be a dangerous sport. Bronchospasm can develop in asthmatic patients and cause airway obstruction. Airway obstruction may be localized to the distal airway which prevents gas elimination. Uncontrolled expansion of the distal airway may result in pulmonary barotrauma. There is also the risk of a gas embolism. Asthmatic divers can also aspirate seawater which may induce bronchospasm. Pollen contamination of their oxygen tank may exacerbate atopic asthma in patients. Diving may be hazardous to the lung function of patients with asthma. Despite the risks of SCUBA diving, many asthmatic individuals can dive without serious diving events. Diving evaluations for asthmatic patients have focused on a thorough patient history, spirometry, allergy testing, and bronchial challenges. For patients that wish to dive, their asthma should be well controlled without current chest symptoms. Patients should have a normal spirometry. Some diving societies recommend that an asthmatic patient should successfully pass a bronchial provocation challenge. Recommendations also state that exercise-, emotion-, and cold-induced asthmatics should not dive. Asthmatic patients requiring rescue medication within 48 h should not dive.

  20. SCUBA Diving and Asthma: Clinical Recommendations and Safety.

    PubMed

    Coop, Christopher A; Adams, Karla E; Webb, Charles N

    2016-02-01

    The objective of this article is to review the available studies regarding asthma and SCUBA (self-contained underwater breathing apparatus) diving. A literature search was conducted in MEDLINE to identify peer-reviewed articles related to asthma and SCUBA diving using the following keywords: asthma, allergy, and SCUBA diving. SCUBA diving is a popular sport with more than 9 million divers in the USA. SCUBA diving can be a dangerous sport. Bronchospasm can develop in asthmatic patients and cause airway obstruction. Airway obstruction may be localized to the distal airway which prevents gas elimination. Uncontrolled expansion of the distal airway may result in pulmonary barotrauma. There is also the risk of a gas embolism. Asthmatic divers can also aspirate seawater which may induce bronchospasm. Pollen contamination of their oxygen tank may exacerbate atopic asthma in patients. Diving may be hazardous to the lung function of patients with asthma. Despite the risks of SCUBA diving, many asthmatic individuals can dive without serious diving events. Diving evaluations for asthmatic patients have focused on a thorough patient history, spirometry, allergy testing, and bronchial challenges. For patients that wish to dive, their asthma should be well controlled without current chest symptoms. Patients should have a normal spirometry. Some diving societies recommend that an asthmatic patient should successfully pass a bronchial provocation challenge. Recommendations also state that exercise-, emotion-, and cold-induced asthmatics should not dive. Asthmatic patients requiring rescue medication within 48 h should not dive. PMID:25666876

  1. Scuba diving and pregnancy: can we determine safe limits?

    PubMed

    St Leger Dowse, M; Gunby, A; Moncad, R; Fife, C; Bryson, P

    2006-08-01

    No human data, investigating the effects on the fetus of diving, have been published since 1989. We investigated any potential link between diving while pregnant and fetal abnormalities by evaluating field data from retrospective study No.1 (1990/2) and prospective study No.2 (1996/2000). Some 129 women reported 157 pregnancies over 1,465 dives. Latest gestational age reported while diving was 35 weeks. One respondent reported 92 dives during a single pregnancy, with two dives to 65 m in the 1st trimester. In study No.2 >90% of women ceased diving in the 1st trimester, compared with 65% in the earlier study. Overall, the women did not conduct enough dives per pregnancy, therefore no significant correlation between diving and fetal abnormalities could be established. These data indicate women are increasingly observing the diving industry recommendation and refraining from diving while pregnant. Field studies are not likely to be useful, or the way forward, for future diving and pregnancy research. Differences in placental circulation between humans and other animals limit the applicability of animal research for pregnancy and diving studies. It is unlikely that the effect of scuba diving on the unborn human fetus will be established.

  2. 17 CFR 240.14d-9 - Recommendation or solicitation by the subject company and others.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Recommendation or solicitation by the subject company and others. (a) Pre-commencement communications. A communication by a person described in paragraph (e) of this section with respect to a tender offer will not be... commenced under § 240.14d-2; and (2) The communication is filed under cover of Schedule 14D-9 (§...

  3. 17 CFR 240.14d-6 - Disclosure of tender offer information to security holders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... information to security holders. 240.14d-6 Section 240.14d-6 Commodity and Securities Exchanges SECURITIES AND... information to security holders. (a) Information required on date of commencement—(1) Long-form publication. If a tender offer is published, sent or given to security holders on the date of commencement...

  4. [ENT examination in SCUBA divers and ENT pathologies restricting diving].

    PubMed

    Hizalan, Ibrahim; Ildiz, Faruk; Uzun, Cem; Keskin, Gürkan

    2002-01-01

    SCUBA diving can be safely performed if a careful pre-dive examination regarding the medical standards of diving is performed, and if all necessary precautions are taken with attention being paid to the potential risks of diving. The most frequent medical problems arising from SCUBA diving fall into the otolaryngology discipline; thus, candidates should be examined in terms of ENT disorders that may prevent them from diving. This article aims to review particular aspects of ENT examination, investigation methods, and criteria for candidates

  5. A forensic diving medicine examination of a highly publicised scuba diving fatality.

    PubMed

    Edmonds, Carl

    2012-12-01

    A high-profile diving death occurred in 2003 at the site of the wreck of the SS Yongala off the Queensland coast. The victim's buddy, her husband, was accused of her murder and found guilty of manslaughter in an Australian court. A detailed analysis of all the evidence concerning this fatality suggests alternative medical reasons for her death. The value of decompression computers in determining the diving details and of CT scans in clarifying autopsy findings is demonstrated. The victim was medically, physically and psychologically unfit to undertake the fatal dive. She was inexperienced and inadequately supervised. She was over-weighted and exposed for the first time to difficult currents. The analysis of the dive demonstrates how important it is to consider the interaction of all factors and to not make deductions from individual items of information. It also highlights the importance of early liaison between expert divers, technicians, diving clinicians and pathologists, if inappropriate conclusions are to be avoided.

  6. Saturated fat (image)

    MedlinePlus

    ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food label, pay close ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food label, pay close ...

  7. Training rats to voluntarily dive underwater: investigations of the mammalian diving response.

    PubMed

    McCulloch, Paul F

    2014-01-01

    Underwater submergence produces autonomic changes that are observed in virtually all diving animals. This reflexly-induced response consists of apnea, a parasympathetically-induced bradycardia and a sympathetically-induced alteration of vascular resistance that maintains blood flow to the heart, brain and exercising muscles. While many of the metabolic and cardiorespiratory aspects of the diving response have been studied in marine animals, investigations of the central integrative aspects of this brainstem reflex have been relatively lacking. Because the physiology and neuroanatomy of the rat are well characterized, the rat can be used to help ascertain the central pathways of the mammalian diving response. Detailed instructions are provided on how to train rats to swim and voluntarily dive underwater through a 5 m long Plexiglas maze. Considerations regarding tank design and procedure room requirements are also given. The behavioral training is conducted in such a way as to reduce the stressfulness that could otherwise be associated with forced underwater submergence, thus minimizing activation of central stress pathways. The training procedures are not technically difficult, but they can be time-consuming. Since behavioral training of animals can only provide a model to be used with other experimental techniques, examples of how voluntarily diving rats have been used in conjunction with other physiological and neuroanatomical research techniques, and how the basic training procedures may need to be modified to accommodate these techniques, are also provided. These experiments show that voluntarily diving rats exhibit the same cardiorespiratory changes typically seen in other diving animals. The ease with which rats can be trained to voluntarily dive underwater, and the already available data from rats collected in other neurophysiological studies, makes voluntarily diving rats a good behavioral model to be used in studies investigating the central aspects of the

  8. Training rats to voluntarily dive underwater: investigations of the mammalian diving response.

    PubMed

    McCulloch, Paul F

    2014-11-12

    Underwater submergence produces autonomic changes that are observed in virtually all diving animals. This reflexly-induced response consists of apnea, a parasympathetically-induced bradycardia and a sympathetically-induced alteration of vascular resistance that maintains blood flow to the heart, brain and exercising muscles. While many of the metabolic and cardiorespiratory aspects of the diving response have been studied in marine animals, investigations of the central integrative aspects of this brainstem reflex have been relatively lacking. Because the physiology and neuroanatomy of the rat are well characterized, the rat can be used to help ascertain the central pathways of the mammalian diving response. Detailed instructions are provided on how to train rats to swim and voluntarily dive underwater through a 5 m long Plexiglas maze. Considerations regarding tank design and procedure room requirements are also given. The behavioral training is conducted in such a way as to reduce the stressfulness that could otherwise be associated with forced underwater submergence, thus minimizing activation of central stress pathways. The training procedures are not technically difficult, but they can be time-consuming. Since behavioral training of animals can only provide a model to be used with other experimental techniques, examples of how voluntarily diving rats have been used in conjunction with other physiological and neuroanatomical research techniques, and how the basic training procedures may need to be modified to accommodate these techniques, are also provided. These experiments show that voluntarily diving rats exhibit the same cardiorespiratory changes typically seen in other diving animals. The ease with which rats can be trained to voluntarily dive underwater, and the already available data from rats collected in other neurophysiological studies, makes voluntarily diving rats a good behavioral model to be used in studies investigating the central aspects of the

  9. Physiology of diving of birds and mammals.

    PubMed

    Butler, P J; Jones, D R

    1997-07-01

    This review concentrates on the physiological responses, and their control, in freely diving birds and mammals that enable them to remain submerged and sometimes quite active for extended periods of time. Recent developments in technology have provided much detailed information on the behavior of these fascinating animals. Unfortunately, the advances in technology have been insufficient to enable physiologists to obtain anything like the same level of detail on the metabolic rate and physiological adjustments that occur during natural diving. This has led to much speculation and calculations based on many assumptions concerning usable oxygen stores and metabolic rate during diving, in an attempt to explain the observed behavior. Despite their shortcomings, these calculations have provided useful insights into the degree of adaptations of various species of aquatic birds and mammals. Many of them, e.g., ducks, smaller penguins, fur seals, and Weddell seals, seem able to metabolize aerobically, when diving, at approximately the same (if not greater) rate as they do at the surface. Their enhanced oxygen stores are able to support aerobic metabolism, at what would not be considered unusually low levels, for the duration of the dives, although there are probably circulatory readjustments to ensure that the oxygen stores are managed judiciously. For other species, such as the larger penguins, South Georgian shag, and female elephant seals, there is a general consensus that they must either be reducing their aerobic metabolic rate when diving, possibly by way of regional hypothermia, and/or producing ATP, at least partly, by anaerobiosis and metabolizing the lactic acid when at the surface (although this is hardly likely in the case of the female elephant seals). Circulation is the proximate regulator of metabolism during aerobic diving, and heart rate is the best single indicator of circulatory adjustment. During voluntary dives, heart rates range from extreme

  10. Metabolic regulation in diving birds and mammals.

    PubMed

    Butler, Patrick J

    2004-08-12

    Ducks, fur seals, Weddell seals and probably most cetaceans seem to be able to dive and remain aerobic for durations that are consistent with their elevated stores of usable oxygen and their metabolic rate while diving being similar to that when they are resting at the surface of the water. Ducks, in fact, have a high metabolic rate while diving, mainly because of their large positive buoyancy, but other species have relatively low buoyancy, are better streamlined and use lift-based rather than drag-based propulsion. However, species such as the larger penguins, grey seals and elephant seals seem to achieve the impossible by performing a substantial proportion of their dives for periods longer than would be expected on the above assumptions, and yet remaining aerobic. The logical conclusion is that during such dives these species reduce their metabolic rate below the resting level (hypometabolism) and, in some of them, there is a regional reduction in body temperature (hypothermia) which may contribute to the reduction in metabolic rate. PMID:15288601

  11. Military diving training improved arterial compliance.

    PubMed

    Mourot, L; Golé, Y; Louge, P; Fontanari, P; Regnard, J; Boussuges, A

    2009-06-01

    This study was aimed at investigating whether repeated SCUBA diving might induce long term cardiovascular and autonomic modifications. In 11 military mine clearance diving students, arterial compliance (ultrasound scan study of brachial artery and ratio of stroke volume to pulse pressure: SV/PP), resting spectral analyses of heart rate and blood pressure variability, and a cold pressor test were performed before and after a 15-week military diving training course. After the diving training, arterial compliance was improved, as indicated by the significant increase in brachial arterial compliance (from 24+/-10 to 37+/-14 ml.mmHg (-1)) and SV/PP (from 1.7+/-0.2 to 1.9+/-0.2 ml.mmHg (-1)), and by the significant decrease in systolic, diastolic and pulse pressures (from 130+/-8 to 120+/-7; from 71+/-4 to 67+/-4; and from 58+/-8 to 53+/-5 mmHg, respectively). The peak oxygen uptake increased significantly from 54.3+/-2.0 to 56.8+/-4.0 mL.kg (-1).min (-1). Finally, the vasoconstrictive response during the cold pressor test increased (p<0.05). These findings point to a positive effect of a 15-week military diving training course on vascular function, and for a concomitant development of some peripheral vascular acclimatization to cold.

  12. Cardiovascular and thermal responses to SCUBA diving.

    PubMed

    Doubt, T J

    1996-05-01

    Recreational SCUBA diving exposes individuals to environmental stresses not often encountered in other types of activity. These stresses include increased ambient pressure, raised partial pressure of O(2), increased resistance to movement, added weight and drag of diving equipment, cold stress, and a higher breathing resistance. One means to understand how such stresses affect a diver is to employ the stress-strain-adaptive response model. Physiologic adaptations, like an increase in VO(2) in response to cold stress, will minimize the strain placed on thermal balance. Nonphysiologic adaptive responses include those behavioral and equipment interventions that isolate the diver from a particular stress. Self-contained underwater breathing apparatus (SCUBA) isolates the diver from the inability to extract O(2) from the water; dive garments minimize the stress of cold water immersion. This review will focus on cardiorespiratory and thermal responses to SCUBA diving, using the stress-strain-adaptive response model to illustrate the interaction between diver and environment. Some responses like hyperventilation, cardiac arrhythmias, or cold injury due to vasoconstriction are not considered adaptive but are realistic possibilities in diving environments.

  13. [Pregnancy and scuba diving: what precautions?].

    PubMed

    Morales, M; Dumps, P; Extermann, P

    1999-05-01

    Scuba diving is a leisure activity increasingly popular amongst women. Many women are concerned about the risks associated with diving and a known or planned pregnancy. In order to advise these young women, we have reviewed the literature concerning women and diving as well as animal studies on the subject. The different international federations and the Undersea and Hyperbaric Medical Society advise against scuba diving for pregnant women or those planning a pregnancy, but no randomized trials or trials provide a solid scientific basis. The fetal circulation is characterized by the exclusion of the pulmonary circulation by 2 right to left shunts. As the lung appears to act as a filter against the progression of micro-bubbles to the main circulation, the fetus may be therefore particularly exposed to gas emboli. However, the placenta could play this role in certain animal species. Nitrox diving appears to be particularly promising, but studies on the subject are still insufficient to recommend it for pregnant women.

  14. Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.

    PubMed

    Meir, Jessica U; Robinson, Patrick W; Vilchis, L Ignacio; Kooyman, Gerald L; Costa, Daniel P; Ponganis, Paul J

    2013-01-01

    Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2) measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris), demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest). This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its most "natural

  15. Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.

    PubMed

    Meir, Jessica U; Robinson, Patrick W; Vilchis, L Ignacio; Kooyman, Gerald L; Costa, Daniel P; Ponganis, Paul J

    2013-01-01

    Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2) measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris), demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest). This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its most "natural

  16. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  17. Use of a mobile diving support vessel, Offshore California

    SciTech Connect

    Carroll, J.P.

    1983-03-01

    The Blue Dolphin is a converted workboat with a one-atmosphere manipulator bell diving system. It provides diving support for Chevron's offshore drilling program. This support includes underwater inspection, repair and salvage.

  18. Barotrauma of the ears and sinuses after scuba diving.

    PubMed

    Becker, G D; Parell, G J

    2001-05-01

    The pathophysiology, differential diagnosis, and currently available management of barotrauma affecting the ears and sinuses after scuba diving are reviewed, along with medical standards for resuming scuba diving after barotrauma has resolved.

  19. Habituation of the cardiac response to involuntary diving in diving and dabbling ducks.

    PubMed

    Gabbott, G R; Jones, D R

    1987-09-01

    1. Bradycardia in response to forced submergence was habituated in dabbling (Anas platyrhynchos, Linnaeus) and diving (Aythya americana, Eyton) ducks by repetitively submerging the animals, each day for several days, for periods of 40 and 20 s, respectively. The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Diving bradycardia is driven by chemoreceptors in the dabbler and caused by stimulation of narial receptors in the diver. 2. Mean arterial blood pressure in dives was unchanged from pre-dive levels in both naive and trained dabbling ducks. PaO2, PaCO2 and pHa at the end of a dive were similar before and after habituation training. 3. Bradycardia occurred in dives by habituated dabbling ducks if the animal breathed 15% O2 before submergence. The ventilatory responses to breathing high and low levels of oxygen were unaffected by habituation training. 4. The changes in blood gases during dives by naive and habituated dabbling ducks were the same: therefore, in the absence of a demonstrated decrement in receptor chemosensitivity or efferent potency, the locus of habituation must reside in the central nervous system. PMID:3694117

  20. Recreational technical diving part 1: an introduction to technical diving methods and activities.

    PubMed

    Mitchell, Simon J; Doolette, David J

    2013-06-01

    Technical divers use gases other than air and advanced equipment configurations to conduct dives that are deeper and/or longer than typical recreational air dives. The use of oxygen-nitrogen (nitrox) mixes with oxygen fractions higher than air results in longer no-decompression limits for shallow diving, and faster decompression from deeper dives. For depths beyond the air-diving range, technical divers mix helium, a light non-narcotic gas, with nitrogen and oxygen to produce 'trimix'. These blends are tailored to the depth of intended use with a fraction of oxygen calculated to produce an inspired oxygen partial pressure unlikely to cause cerebral oxygen toxicity and a nitrogen fraction calculated to produce a tolerable degree of nitrogen narcosis. A typical deep technical dive will involve the use of trimix at the target depth with changes to gases containing more oxygen and less inert gas during the decompression. Open-circuit scuba may be used to carry and utilise such gases, but this is very wasteful of expensive helium. There is increasing use of closed-circuit 'rebreather' devices. These recycle expired gas and potentially limit gas consumption to a small amount of inert gas to maintain the volume of the breathing circuit during descent and the amount of oxygen metabolised by the diver. This paper reviews the basic approach to planning and execution of dives using these methods to better inform physicians of the physical demands and risks.

  1. Summer diving behavior of male walruses in Bristol Bay, Alaska

    USGS Publications Warehouse

    Jay, C.V.; Farley, Sean D.; Garner, G.W.

    2001-01-01

    Pacific walruses (Odobenus rosmarus divergens) make trips from ice or land haul-out sites to forage for benthic prey. We describe dive and trip characteristics from time-depth-recorder data collected over a one-month period during summer from four male Pacific walruses in Bristol Bay, Alaska. Dives were classified into four types. Shallow (4 m), short (2.7 min), square-shaped dives accounted for 11% of trip time, and many were probably associated with traveling. Shallow (2 m) and very short (0.5 min) dives composed only 1% of trip time. Deep (41 m), long (7.2 min), square-shaped dives accounted for 46% of trip time and were undoubtedly associated with benthic foraging. V-shaped dives ranged widely in depth, were of moderate duration (4.7 min), and composed 3% of trip time. These dives may have been associated with navigation or exploration of the seafloor for potential prey habitat. Surface intervals between dives were similar among dive types, and generally lasted 1-2 min. Total foraging time was strongly correlated with trip duration and there was no apparent diel pattern of diving in any dive type among animals. We found no correlation between dive duration and postdive surface interval within dive types, suggesting that diving occurred within aerobic dive limits. Trip duration varied considerably within and among walruses (0.3-9.4 d), and there was evidence that some of the very short trips were unrelated to foraging. Overall, walruses were in the water for 76.6% of the time, of which 60.3% was spent diving.

  2. Recurrent alternobaric facial paralysis resulting from scuba diving.

    PubMed

    Becker, G D

    1983-05-01

    Only one detailed case of alternobaric (referring to alternating pressure changes) facial paralysis resulting from scuba diving has been reported in the world literature. This article describes the dive profile and clinical course of a commercial diver who developed facial paralysis after scuba diving on three different occasions. Probable pathophysiologies, identification of the diver at risk, treatment and prophylactic measures are reviewed. Additional cases from the literature due to scuba diving and flying are cited.

  3. Pneumocephalus after an uneventful scuba dive.

    PubMed

    Zeba, Ivica; Barkovic, Igor; Knezevic, Sinisa; Lender, Dubravka Matanic; Bralic, Marina; Bulat-Kardum, Ljiljana

    2010-05-01

    Scuba diving has become increasingly popular in the last 20 yr. Although it is considered safe, accidents, sometimes with fatal outcomes, do occur. The incidence of diving-related CNS barotrauma is low and it has been reported very infrequently. The clinical presentation may range from minimal dysesthesias to complete quadriplegia, encephalopathy, or death. In this paper we present a case of pneumocephalus in a 36-yr-old male scuba diver that presented with minor neurologic symptoms. A discussion, including a review of the literature, is also presented. The authors recommend that diving-induced neurologic dysbarism syndromes, including pneumocephalus, should be considered a possible cause when a scuba diver presents with neurologic symptoms, even minor ones.

  4. Effects of scuba diving on vascular repair mechanisms.

    PubMed

    Culic, Vedrana Cikes; Van Craenenbroeck, Emeline; Muzinic, Nikolina Rezic; Ljubkovic, Marko; Marinovic, Jasna; Conraads, Viviane; Dujic, Zeljko

    2014-01-01

    A single air dive causes transient endothelial dysfunction. Endothelial progenitor cells (EPCs) and circulating angiogenic cells (CAC) contribute synergistically to endothelial repair. In this study (1) the acute effects of diving on EPC numbers and CAC migration and (2) the influence of the gas mixture (air/nitrox-36) was investigated. Ten divers performed two dives to 18 meters on Day (D) 1 and D3, using air. After 15 days, dives were repeated with nitrox-36. Blood sampling took place before and immediately after diving. Circulating EPCs were quantified by flow cytometry, CAC migration of culture was assessed on D7. When diving on air, a trend for reduced EPC numbers is observed post-dive, which is persistent on D1 and D3. CAC migration tends to improve acutely following diving. These effects are more pronounced with nitrox-36 dives. Diving acutely affects EPC numbers and CAC function, and to a larger extent when diving with nitrox-36. The diving-induced oxidative stress may influence recruitment or survival of EPC. The functional improvement of CAC could be a compensatory mechanism to maintain endothelial homeostasis.

  5. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  6. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  7. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  8. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  9. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... dive area from ascending directly to the surface. ... 29 Labor 5 2013-07-01 2013-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied...

  10. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... dive area from ascending directly to the surface. ... 29 Labor 5 2014-07-01 2014-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied...

  11. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... dive area from ascending directly to the surface. ... 29 Labor 5 2011-07-01 2011-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied...

  12. Effects of scuba diving on vascular repair mechanisms.

    PubMed

    Culic, Vedrana Cikes; Van Craenenbroeck, Emeline; Muzinic, Nikolina Rezic; Ljubkovic, Marko; Marinovic, Jasna; Conraads, Viviane; Dujic, Zeljko

    2014-01-01

    A single air dive causes transient endothelial dysfunction. Endothelial progenitor cells (EPCs) and circulating angiogenic cells (CAC) contribute synergistically to endothelial repair. In this study (1) the acute effects of diving on EPC numbers and CAC migration and (2) the influence of the gas mixture (air/nitrox-36) was investigated. Ten divers performed two dives to 18 meters on Day (D) 1 and D3, using air. After 15 days, dives were repeated with nitrox-36. Blood sampling took place before and immediately after diving. Circulating EPCs were quantified by flow cytometry, CAC migration of culture was assessed on D7. When diving on air, a trend for reduced EPC numbers is observed post-dive, which is persistent on D1 and D3. CAC migration tends to improve acutely following diving. These effects are more pronounced with nitrox-36 dives. Diving acutely affects EPC numbers and CAC function, and to a larger extent when diving with nitrox-36. The diving-induced oxidative stress may influence recruitment or survival of EPC. The functional improvement of CAC could be a compensatory mechanism to maintain endothelial homeostasis. PMID:24851546

  13. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... mask and tubing shall be available at the dive location. (d) Planning and assessment. Planning of a...) Diving mode; (2) Surface and underwater conditions and hazards; (3) Breathing gas supply (including... designation or residual inert gas status of dive team members; (8) Decompression and treatment...

  14. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... mask and tubing shall be available at the dive location. (d) Planning and assessment. Planning of a...) Diving mode; (2) Surface and underwater conditions and hazards; (3) Breathing gas supply (including... designation or residual inert gas status of dive team members; (8) Decompression and treatment...

  15. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Pre-dive procedures. 1910.421 Section 1910.421 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.421 Pre-dive procedures. (a)...

  16. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... mask and tubing shall be available at the dive location. (d) Planning and assessment. Planning of a...) Diving mode; (2) Surface and underwater conditions and hazards; (3) Breathing gas supply (including... designation or residual inert gas status of dive team members; (8) Decompression and treatment...

  17. O2 store management in diving emperor penguins

    PubMed Central

    Ponganis, P. J.; Stockard, T. K.; Meir, J. U.; Williams, C. L.; Ponganis, K. V.; Howard, R.

    2009-01-01

    Summary In order to further define O2 store utilization during dives and understand the physiological basis of the aerobic dive limit (ADL, dive duration associated with the onset of post-dive blood lactate accumulation), emperor penguins (Aptenodytes forsteri) were equipped with either a blood partial pressure of oxygen (PO2) recorder or a blood sampler while they were diving at an isolated dive hole in the sea ice of McMurdo Sound, Antarctica. Arterial PO2 profiles (57 dives) revealed that (a) pre-dive PO2 was greater than that at rest, (b) PO2 transiently increased during descent and (c) post-dive PO2 reached that at rest in 1.92±1.89 min (N=53). Venous PO2 profiles (130 dives) revealed that (a) pre-dive venous PO2 was greater than that at rest prior to 61% of dives, (b) in 90% of dives venous PO2 transiently increased with a mean maximum PO2 of 53±18 mmHg and a mean increase in PO2 of 11±12 mmHg, (c) in 78% of dives, this peak venous PO2 occurred within the first 3 min, and (d) post-dive venous PO2 reached that at rest within 2.23±2.64 min (N=84). Arterial and venous PO2 values in blood samples collected 1–3 min into dives were greater than or near to the respective values at rest. Blood lactate concentration was less than 2 mmol l–1 as far as 10.5 min into dives, well beyond the known ADL of 5.6 min. Mean arterial and venous PN2 of samples collected at 20–37 m depth were 2.5 times those at the surface, both being 2.1±0.7 atmospheres absolute (ATA; N=3 each), and were not significantly different. These findings are consistent with the maintenance of gas exchange during dives (elevated arterial and venous PO2 and PN2 during dives), muscle ischemia during dives (elevated venous PO2, lack of lactate washout into blood during dives), and arterio-venous shunting of blood both during the surface period (venous PO2 greater than that at rest) and during dives (arterialized venous PO2 values during descent, equivalent arterial and venous PN2 values during

  18. Deep-diving foraging behaviour of sperm whales (Physeter macrocephalus).

    PubMed

    Watwood, Stephanie L; Miller, Patrick J O; Johnson, Mark; Madsen, Peter T; Tyack, Peter L

    2006-05-01

    1. Digital tags were used to describe diving and vocal behaviour of sperm whales during 198 complete and partial foraging dives made by 37 individual sperm whales in the Atlantic Ocean, the Gulf of Mexico and the Ligurian Sea. 2. The maximum depth of dive averaged by individual differed across the three regions and was 985 m (SD = 124.3), 644 m (123.4) and 827 m (60.3), respectively. An average dive cycle consisted of a 45 min (6.3) dive with a 9 min (3.0) surface interval, with no significant differences among regions. On average, whales spent greater than 72% of their time in foraging dive cycles. 3. Whales produced regular clicks for 81% (4.1) of a dive and 64% (14.6) of the descent phase. The occurrence of buzz vocalizations (also called 'creaks') as an indicator of the foraging phase of a dive showed no difference in mean prey capture attempts per dive between regions [18 buzzes/dive (7.6)]. Sperm whales descended a mean of 392 m (144) from the start of regular clicking to the first buzz, which supports the hypothesis that regular clicks function as a long-range biosonar. 4. There were no significant differences in the duration of the foraging phase [28 min (6.0)] or percentage of the dive duration in the foraging phase [62% (7.3)] between the three regions, with an overall average proportion of time spent actively encountering prey during dive cycles of 0.53 (0.05). Whales maintained their time in the foraging phase by decreasing transit time for deeper foraging dives. 5. Similarity in foraging behaviour in the three regions and high diving efficiencies suggest that the success of sperm whales as mesopelagic predators is due in part to long-range echolocation of deep prey patches, efficient locomotion and a large aerobic capacity during diving.

  19. [Scuba diving and the heart. Cardiac aspects of sport scuba diving].

    PubMed

    Muth, Claus-Martin; Tetzlaff, Kay

    2004-06-01

    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

  20. [Health aspects of diving in ENT medicine. Part I: Diving associated diseases].

    PubMed

    Klingmann, C; Wallner, F

    2004-08-01

    There has been a steady increase in the number of recreational scuba divers in the last years, with a growing number of diving associated diseases involving ENT medicine. Disorders of the ears, sinuses and pharynx are those most common in divers. In particular, external otitis and barotrauma of the middle ear are commonly treated by every ENT specialist. They usually do not lead to any permanent complaints. Incidents involving the cochleovestibular system are less common, but can result in deafness, vertigo and tinnitus, and therefore have to be treated appropriately. To treat diving medical disorders, the physician has to have some basic understanding of the physical laws that lead to diving incidents. This article will inform the reader of the forces that are encountered by divers, and then give details of the treatment of acute ENT diseases which result from diving incidents.

  1. The dive response redefined: underwater behavior influences cardiac variability in freely diving dolphins.

    PubMed

    Noren, Shawn R; Kendall, Traci; Cuccurullo, Veronica; Williams, Terrie M

    2012-08-15

    A hallmark of the dive response, bradycardia, promotes the conservation of onboard oxygen stores and enables marine mammals to submerge for prolonged periods. A paradox exists when marine mammals are foraging underwater because activity should promote an elevation in heart rate (f(H)) to support increased metabolic demands. To assess the effect of the interaction between the diving response and underwater activity on f(H), we integrated interbeat f(H) with behavioral observations of adult bottlenose dolphins diving and swimming along the coast of the Bahamas. As expected for the dive response, f(H) while resting during submergence (40±6 beats min(-1)) was significantly lower than f(H) while resting at the water surface (105±8 beats min(-1)). The maximum recorded f(H) (f(H,max)) was 128±7 beats min(-1), and occurred during post-dive surface intervals. During submergence, the level of bradycardia was modified by activity. Behaviors such as simple head bobbing at depth increased f(H) by 40% from submerged resting levels. Higher heart rates were observed for horizontal swimming at depth. Indeed, the dolphins operated at 37-58% of their f(H,max) while active at depth and approached 57-79% of their f(H,max) during anticipatory tachycardia as the animals glided to the surface. f(H) was significantly correlated with stroke frequency (range=0-2.5 strokes s(-1), r=0.88, N=25 dives) and calculated swim speed (range=0-5.4 m s(-1), r=0.88, N=25 dives). We find that rather than a static reflex, the dive response is modulated by behavior and exercise in a predictable manner.

  2. Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva "memory dive" study

    PubMed Central

    Slosman, D; de Ribaupierre, S; Chicherio, C; Ludwig, C; Montandon, M; Allaoua, M; Genton, L; Pichard, C; Grousset, A; Mayer, E; Annoni, J; de Ribaupierre, A

    2004-01-01

    Objectives: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months' frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments. Methods: A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by 133Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold water v warm water); and body composition analyses (BMI). Results: (1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found. Conclusions: Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m. PMID:15039241

  3. Serum levels of S-100B after recreational scuba diving.

    PubMed

    Stavrinou, L C; Kalamatianos, T; Stavrinou, P; Papasilekas, T; Psachoulia, C; Tzavara, C; Stranjalis, G

    2011-12-01

    Recreational scuba diving is a sport of increasing popularity. Previous studies indicating subtle brain injury in asymptomatic divers imply a cumulative effect of minor neural insults in association with diving for professional and/or recreational purposes, over the long-term. This is the first study to investigate putative neural tissue burden during recreational scuba diving by measuring circulating levels of S-100B, a sensitive biomarker of brain injury. 5 male divers performed 3 consecutive dives under conservative recreational diving settings (maximum depth 15 m, duration of dive 56 min, ascend rate 1.15 m/min) with an interval of 12 h between each session. Although a small increase in serum S-100B levels after each dive was apparent, this increase did not quite reach statistical significance (p=0.057). Moreover, no abnormal S-100B values were recorded (mean baseline: 0.06 μg/L, mean post-dive: 0.086 μg/L) and no effect of the 3 consecutive dives on changes in S-100B levels was detected. These results suggest that under the experimental conditions tested, diving does not seem to have a discernible and/or cumulative impact on central nervous system integrity. The extent to which variable diving settings and practices as well as individual susceptibility factors underlie putative neural tissue burden in asymptomatic divers, remains to be established.

  4. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations. PMID:3805996

  5. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations.

  6. Influence of repeated daily diving on decompression stress.

    PubMed

    Zanchi, J; Ljubkovic, M; Denoble, P J; Dujic, Z; Ranapurwala, S; Pollock, N W

    2014-06-01

    Acclimatization (an adaptive change in response to repeated environmental exposure) to diving could reduce decompression stress. A decrease in post-dive circulating venous gas emboli (VGE or bubbles) would represent positive acclimatization. The purpose of this study was to determine whether four days of daily diving alter post-dive bubble grades. 16 male divers performed identical no-decompression air dives on 4 consecutive days to 18 meters of sea water for 47 min bottom times. VGE monitoring was performed with transthoracic echocardiography every 20 min for 120 min post-dive. Completion of identical daily dives resulted in progressively decreasing odds (or logit risk) of having relatively higher grade bubbles on consecutive days. The odds on Day 4 were half that of Day 1 (OR 0.50, 95% CI: 0.34, 0.73). The odds ratio for a >III bubble grade on Day 4 was 0.37 (95% CI: 0.20, 0.70) when compared to Day 1. The current study indicates that repetitive daily diving may reduce bubble formation, representing a positive (protective) acclimatization to diving. Further work is required to evaluate the impact of additional days of diving and multiple dive days and to determine if the effect is sufficient to alter the absolute risk of decompression sickness.

  7. Effects of Long-term Diving Training on Cortical Gyrification.

    PubMed

    Zhang, Yuanchao; Zhao, Lu; Bi, Wenwei; Wang, Yue; Wei, Gaoxia; Evans, Alan; Jiang, Tianzi

    2016-01-01

    During human brain development, cortical gyrification, which is believed to facilitate compact wiring of neural circuits, has been shown to follow an inverted U-shaped curve, coinciding with the two-stage neurodevelopmental process of initial synaptic overproduction with subsequent pruning. This trajectory allows postnatal experiences to refine the wiring, which may manifest as endophenotypic changes in cortical gyrification. Diving experts, typical elite athletes who commence intensive motor training at a very young age in their early childhood, serve ideal models for examining the gyrification changes related to long-term intensive diving training. Using local gyrification index (LGI), we compared the cortical gyrification between 12 diving experts and 12 controls. Compared with controls, diving experts showed widespread LGI reductions in regions relevant to diving performance. Negative correlations between LGIs and years of diving training were also observed in diving experts. Further exploratory network efficiency analysis of structural cortical networks, inferred from interregional correlation of LGIs, revealed comparable global and local efficiency in diving experts relative to controls. These findings suggest that gyrification reductions in diving experts may be the result of long-term diving training which could refine the neural circuitry (via synaptic pruning) and might be the anatomical substrate underlying their extraordinary diving performance. PMID:27320849

  8. Effects of Long-term Diving Training on Cortical Gyrification

    PubMed Central

    Zhang, Yuanchao; Zhao, Lu; Bi, Wenwei; Wang, Yue; Wei, Gaoxia; Evans, Alan; Jiang, Tianzi

    2016-01-01

    During human brain development, cortical gyrification, which is believed to facilitate compact wiring of neural circuits, has been shown to follow an inverted U-shaped curve, coinciding with the two-stage neurodevelopmental process of initial synaptic overproduction with subsequent pruning. This trajectory allows postnatal experiences to refine the wiring, which may manifest as endophenotypic changes in cortical gyrification. Diving experts, typical elite athletes who commence intensive motor training at a very young age in their early childhood, serve ideal models for examining the gyrification changes related to long-term intensive diving training. Using local gyrification index (LGI), we compared the cortical gyrification between 12 diving experts and 12 controls. Compared with controls, diving experts showed widespread LGI reductions in regions relevant to diving performance. Negative correlations between LGIs and years of diving training were also observed in diving experts. Further exploratory network efficiency analysis of structural cortical networks, inferred from interregional correlation of LGIs, revealed comparable global and local efficiency in diving experts relative to controls. These findings suggest that gyrification reductions in diving experts may be the result of long-term diving training which could refine the neural circuitry (via synaptic pruning) and might be the anatomical substrate underlying their extraordinary diving performance. PMID:27320849

  9. Pulmonary function in children after open water SCUBA dives.

    PubMed

    Winkler, B E; Tetzlaff, K; Muth, C-M; Hebestreit, H

    2010-10-01

    An increasing number of children and adolescents is diving with Self-Contained Underwater Breathing Apparatus (SCUBA). SCUBA diving is associated with health risks such as pulmonary barotrauma, especially in children and in individuals with airflow limitation. As no data has been published on the effects of open-water diving on pulmonary function in children, the objective of this study was to evaluate the effects of SCUBA dives on airflow in children. 16 healthy children aged 10-13 years underwent spirometry and a cycle-exercise challenge while breathing cold air. They subsequently performed dives to 1-m and 8-m depth in random order. Pulmonary function was measured before and after the exercise challenge and the dives. There were statistically significant decreases in FEV1, FVC, FEV1/FVC, MEF25 and MEF50 after the cold-air exercise challenge and the dives. Changes in lung function following the exercise challenge did not predict the responses to SCUBA diving. In 3 children the post-dive decrements in FEV1 exceeded 10%. These children had a lower body weight and BMI percentile. SCUBA diving in healthy children may be associated with relevant airflow limitation. A low body mass might contribute to diving-associated bronchoconstriction. In the majority of subjects, no clinically relevant airway obstruction could be observed.

  10. The marine mammal dive response is exercise modulated to maximize aerobic dive duration.

    PubMed

    Davis, Randall W; Williams, Terrie M

    2012-08-01

    When aquatically adapted mammals and birds swim submerged, they exhibit a dive response in which breathing ceases, heart rate slows, and blood flow to peripheral tissues and organs is reduced. The most intense dive response occurs during forced submersion which conserves blood oxygen for the brain and heart, thereby preventing asphyxiation. In free-diving animals, the dive response is less profound, and energy metabolism remains aerobic. However, even this relatively moderate bradycardia seems diametrically opposed to the normal cardiovascular response (i.e., tachycardia and peripheral vasodilation) during physical exertion. As a result, there has been a long-standing paradox regarding how aquatic mammals and birds exercise while submerged. We hypothesized based on cardiovascular modeling that heart rate must increase to ensure adequate oxygen delivery to active muscles. Here, we show that heart rate (HR) does indeed increase with flipper or fluke stroke frequency (SF) during voluntary, aerobic dives in Weddell seals (HR = 1.48SF - 8.87) and bottlenose dolphins (HR = 0.99SF + 2.46), respectively, two marine mammal species with different evolutionary lineages. These results support our hypothesis that marine mammals maintain aerobic muscle metabolism while swimming submerged by combining elements of both dive and exercise responses, with one or the other predominating depending on the level of exertion. PMID:22585422

  11. SCUBA-dive-related changes in heart rate in children.

    PubMed

    Winkler, Bernd E; Tetzlaff, Kay; Muth, Claus-Martin; Paulat, Klaus; Hebestreit, Helge

    2011-08-01

    The purpose of this study was to monitor heart rate (HR) and rhythm during open water SCUBA dives. Nine children performed 25-min open water SCUBA dives to 8 m depth. Before, during and after these dives, ECG was recorded. Compared with predive heart rate, heart rate declined by -24 ± 8% (range -36%; -15%) during the dive. In some children a further decline in HR was observed within the last minutes of the dive. Older and taller subjects and those with a high initial HR showed a more pronounced decline in HR. Furthermore singular supraventricular and ventricular extrasystoles were observed in some children. Immersion as well as facial and skin cooling presumably account for the initial decline in heart rate. A further drop in HR within the last minutes of the dive might be related to mild hypothermia. Single supraventricular and ventricular extrasystoles might occur in healthy children during dives.

  12. [Case Report - Really a diving accident?].

    PubMed

    Fichtner, Andreas

    2015-10-01

    A 17 y old male SCUBA diver presents himself for hospital admission after a suspected diving accident. All clinical signs are favouring the initial diagnosis: loss of leg motor function, paresthesia, disturbed vision and headache. What are your further diagnostic and therapeutic steps? Can you proof the initial diagnosis? What differential diagnoses are relevant or even mimicked? PMID:26510103

  13. [Injuries caused by pressure differences while diving].

    PubMed

    Kemmer, A; Welslau, W; Muth, C M

    2005-07-01

    Barotraumas are caused by pressure differences. As described by Boyle's Law, barotraumas develop during the descent phase of diving (and much more rarely during the ascent). The most frequently affected are the ears and paranasal sinuses, in addition to the facial skin and eyes. The most important preventive measure is performing pressure compensation in the affected body cavities. Barotrauma is treated symptomatically. PMID:16041937

  14. Age associated risks of recreational scuba diving.

    PubMed

    Smerz, Richard W

    2006-05-01

    The effect of aging on risk for development of decompression illness in divers has often been reported as an incidental finding in epidemiological analyses of diving accidents. No previous publications have specifically attempted to quantify or qualify those risks if present. This study demonstrates that aging increases risk for injury overall, serious injury in particular, and lessens recovery potential.

  15. [Case Report - Really a diving accident?].

    PubMed

    Fichtner, Andreas

    2015-10-01

    A 17 y old male SCUBA diver presents himself for hospital admission after a suspected diving accident. All clinical signs are favouring the initial diagnosis: loss of leg motor function, paresthesia, disturbed vision and headache. What are your further diagnostic and therapeutic steps? Can you proof the initial diagnosis? What differential diagnoses are relevant or even mimicked?

  16. Diving injuries to the inner ear.

    PubMed

    Farmer, J C

    1977-01-01

    Most of the previous literature concerning otologic problems in compressed gas environments has emphasized middle ear barotrauma. With recent increases in commercial, military, and sport diving to deeper depths, inner ear disturbances during these exposures have been noted more frequently. Studies of inner ear physiology and pathology during diving indicate that the causes and treatment of these problems differ depending upon the phase and type of diving. Humans exposed to simulated depths of up to 305 meters without barotrauma or decompression sickness develop transient, conductive hearing losses with no audiometric evidence of cochlear dysfunction. Transient vertigo and nystagmus during diving have been noted with caloric stimulation, resulting from the unequal entry of cold water into the external auditory canals, and with asymmetric middle ear pressure equilibration during ascent and descent (alternobaric vertigo). Equilibrium disturbances noted with nitrogen narcosis, oxygen toxicity, hypercarbia, or hypoxia appear primarily related to the effects of these conditions upon the central nervous system and not to specific vestibular end-organ dysfunction. Compression of humans in helium-oxygen at depths greater than 152.4 meters results in transient symptoms of tremor, dizziness, and nausea plus decrements in postural equilibrium and psychomotor performance, the high pressure nervous syndrome. Vestibular function studies during these conditions indicate that these problems are due to central dysfunction and not to vestibular end-organ dysfunction. Persistent inner ear injuries have been noted during several phases of diving: 1) Such injuries during compression (inner ear barotrauma) have been related to round window ruptures occurring with straining, or a Valsalva's maneuver during inadequate middle ear pressure equilibration. Divers who develop cochlear and/or vestibular symptoms during shallow diving in which decompression sickness is unlikely or during

  17. Diving injuries to the inner ear.

    PubMed

    Farmer, J C

    1977-01-01

    Most of the previous literature concerning otologic problems in compressed gas environments has emphasized middle ear barotrauma. With recent increases in commercial, military, and sport diving to deeper depths, inner ear disturbances during these exposures have been noted more frequently. Studies of inner ear physiology and pathology during diving indicate that the causes and treatment of these problems differ depending upon the phase and type of diving. Humans exposed to simulated depths of up to 305 meters without barotrauma or decompression sickness develop transient, conductive hearing losses with no audiometric evidence of cochlear dysfunction. Transient vertigo and nystagmus during diving have been noted with caloric stimulation, resulting from the unequal entry of cold water into the external auditory canals, and with asymmetric middle ear pressure equilibration during ascent and descent (alternobaric vertigo). Equilibrium disturbances noted with nitrogen narcosis, oxygen toxicity, hypercarbia, or hypoxia appear primarily related to the effects of these conditions upon the central nervous system and not to specific vestibular end-organ dysfunction. Compression of humans in helium-oxygen at depths greater than 152.4 meters results in transient symptoms of tremor, dizziness, and nausea plus decrements in postural equilibrium and psychomotor performance, the high pressure nervous syndrome. Vestibular function studies during these conditions indicate that these problems are due to central dysfunction and not to vestibular end-organ dysfunction. Persistent inner ear injuries have been noted during several phases of diving: 1) Such injuries during compression (inner ear barotrauma) have been related to round window ruptures occurring with straining, or a Valsalva's maneuver during inadequate middle ear pressure equilibration. Divers who develop cochlear and/or vestibular symptoms during shallow diving in which decompression sickness is unlikely or during

  18. Oxygen uptake during post dive recovery in a diving bird Aythya fuligula: implications for optimal foraging models.

    PubMed

    Parkes, Roland; Halsey, Lewis G; Woakes, Anthony J; Holder, Roger L; Butler, Patrick J

    2002-12-01

    The rate of oxygen uptake at the surface between dives was measured for four tufted ducks, Aythya fuligula, during bouts of foraging dives to a depth of 1.8 m. The ducks surfaced into a respirometer box after each dive so that the rate of oxygen uptake ((O(2))) could be measured. (O(2)) decreased over time at the surface and there was a particularly rapid phase of oxygen uptake for approximately the first 3s. The specific shape of the oxygen uptake curve is dependent upon the duration of the preceding dive. The uptake curve after longer dives was significantly steeper during the first 3s at the surface than after shorter dives, although (O(2)) after the first 3s was not significantly different between these two dive duration bins. Thus, the mean total oxygen uptake (V(O(2))) was higher after surface periods following longer dives. Due to the high (O(2)) during the initial part of the surface period, the curve associated with longer dives was statistically biphasic, with the point of inflection at 3.3s. The curve for shorter dives was not statistically biphasic. The birds may increase their respiratory frequency during the first 3s after longer dives, producing the increased (O(2)), which would enable the birds to resaturate their oxygen stores more rapidly in response to the increased oxygen depletion of the longer submergence time. PMID:12432016

  19. [Hyperbaric therapy and diving medicine - diving medicine - present state and prospects].

    PubMed

    Winkler, Bernd; Muth, Claus-Martin; Piepho, Tim

    2015-10-01

    The diving accident (decompression incident, DCI) occurs in the decompression phase of dives. The DCI can either be caused by an arterial gas embolism (AGE) subsequent to a pulmonary barotrauma or by the formation of inert gas bubbles subsequent to a reduction of ambient pressure during the ascent from depth. In contrast to the traditional assumption that decompression incidents only occur if decompression rules are neglected, recent data indicate that a vast amount of diving accidents occur even though divers adhered to the rules. Hence, there is a large inter- and intraindividual variability in the predisposition for diving accidents. Within the past few years, the molecular understanding of the pathophysiology of diving accidents has improved considerably. It is now well accepted that pro-inflammatory and pro-coagulatory mechanisms play a central role. Moreover, microparticles are increasingly discussed in the pathogenesis of diving accidents. These new molecular findings have not yet resulted in new therapeutic approaches. However, new approaches of preconditioning before the dive have been developed which are intended to reduce the risk of diving accidents. The symptoms of a diving accident show a large variability and range. They reach from pruritus over tension in the female breast, marbled skin and pain in the joints to severe neurological disability like paraplegia or hemiplegia. Furthermore, pulmonary symptoms can be a result of a pulmonary gas embolism and/or a tension pneumothorax. Extreme cases can also manifest as generalized, difficult-to-treat seizures, loss of consciousness or even death. The evidence-based therapy of diving accidents consists of an immediate application of 100% inspiratory O2. This can be performed via a demand valve, face mask with reservoir bag or ventilation bag connected to a reservoir bag. Fluid substitution is performed by i. v. infusion of 500-1000ml/h of cristalloids. If consciousness is not impaired, the diver is

  20. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Surface-supplied mixed-gas diving. 197.434 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.434 Surface-supplied mixed-gas diving. The diving supervisor shall insure that— (a) When...

  1. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times... physically confining space; (d) A closed bell is used for dives at depths greater than 300 fsw, except when diving is conducted in a physically confining space; (e) A separate dive team member tends each diver...

  2. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times... physically confining space; (d) A closed bell is used for dives at depths greater than 300 fsw, except when diving is conducted in a physically confining space; (e) A separate dive team member tends each diver...

  3. Respiratory and cardiovascular control during diving in birds and mammals.

    PubMed

    Butler, P J

    1982-10-01

    Recent studies on freely diving birds and mammals indicate that, contrary to the classical hypothesis, the majority of dives are aerobic with minimal cardiovascular adjustments (i.e. bradycardia and selective vasoconstriction). It is postulated that during these aerobic dives the cardiovascular adjustments result from the opposing influences of exercise and the classical diving response, with the bias towards the exercise response. It is envisaged that the active muscles, as well as the brain and heart, are adequately supplied with blood to enable them to metabolize aerobically. Intense mental activity, particularly in carnivores seeking their prey, may also attenuate the classical response. Aerobic dives are usually terminated well before the oxygen stores are depleted, and another dive follows once they have been replenished. In this way a series of dives is performed. Prolonged dives are endured as a result of a shift towards the classical response of bradycardia, presumably more intense vasoconstriction, and anaerobiosis. This may be a form of alarm response, particularly in small animals such as ducks and coypus, or it may be a means of allowing the marine birds and mammals that dive deeply for their food to engage in unusually long hunting expeditions. For those that dive under ice, it may also allow long periods of underwater exploration as well as being a safety mechanism should the animal become disoriented. PMID:6757368

  4. The indigenous fisherman divers of Thailand: diving practices.

    PubMed

    Gold, D; Aiyarak, S; Wongcharoenyong, S; Geater, A; Juengprasert, W; Gerth, W A

    2000-01-01

    Diving practices of a group of indigenous people living on Thailand's west coast were investigated. Village chiefs were first interviewed using a questionnaire. Three hundred and forty-two active divers were then interviewed by health care workers using a second questionnaire. Field observation was used to further develop information and confirm diving practices. Divers in 6 villages, whose basic means of making a living is from diving for marine products such as fish and shellfish, have diving patterns that put them at substantial risk of decompression illness. Breathing air from a primitive compressor through approximately 100 m of air hose, these divers have long bottom times coupled with short surface intervals. Forty-six point two percent of the divers indicated that they would not make a stop during ascent from a long deep dive (40 m for 30 min). When comparing their previous day of diving to the U.S. Navy Standard Air Decompression Table (U.S. Navy, 1993), 72.1% exceeded the no-decompression limits set by the tables. Diving patterns point to a need for more in-depth research into the diving patterns of this indigenous group. Future research should include the use of dive logging devices to record depths and times. There is also a need to provide divers with information and training to reinforce positive practices and strengthen knowledge of the risks associated with their current diving practices.

  5. The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores?

    PubMed

    Croll, D A; Acevedo-Gutiérrez, A; Tershy, B R; Urbán-Ramírez, J

    2001-07-01

    Many diving seabirds and marine mammals have been found to regularly exceed their theoretical aerobic dive limit (TADL). No animals have been found to dive for durations that are consistently shorter than their TADL. We attached time-depth recorders to 7 blue whales and 15 fin whales (family Balaenopteridae). The diving behavior of both species was similar, and we distinguished between foraging and traveling dives. Foraging dives in both species were deeper, longer in duration and distinguished by a series of vertical excursions where lunge feeding presumably occurred. Foraging blue whales lunged 2.4 (+/-1.13) times per dive, with a maximum of six times and average vertical excursion of 30.2 (+/-10.04) m. Foraging fin whales lunged 1.7 (+/-0.88) times per dive, with a maximum of eight times and average vertical excursion of 21.2 (+/-4.35) m. The maximum rate of ascent of lunges was higher than the maximum rate of descent in both species, indicating that feeding lunges occurred on ascent. Foraging dives were deeper and longer than non-feeding dives in both species. On average, blue whales dived to 140.0 (+/-46.01) m and 7.8 (+/-1.89) min when foraging, and 67.6 (+/-51.46) m and 4.9 (+/-2.53) min when not foraging. Fin whales dived to 97.9 (+/-32.59) m and 6.3 (+/-1.53) min when foraging and to 59.3 (+/-29.67) m and 4.2 (+/-1.67) min when not foraging. The longest dives recorded for both species, 14.7 min for blue whales and 16.9 min for fin whales, were considerably shorter than the TADL of 31.2 and 28.6 min, respectively. An allometric comparison of seven families diving to an average depth of 80-150 m showed a significant relationship between body mass and dive duration once Balaenopteridae whales, with a mean dive duration of 6.8 min, were excluded from the analysis. Thus, the short dive durations of blue whales and fin whales cannot be explained by the shallow distribution of their prey. We propose instead that short duration diving in large whales results from

  6. Diving dentistry: a review of the dental implications of scuba diving.

    PubMed

    Zadik, Y; Drucker, S

    2011-09-01

    In light of the overwhelming popularity of self-contained underwater breathing apparatus (SCUBA) diving, general dental practitioners should be prepared to address complications arising as a result of diving and to provide patients with accurate information. The aim of this article was to introduce the concepts of diving medicine and dentistry to the dentist, and to supply the dental practitioner with some diagnostic tools as well as treatment guidelines. The literature was reviewed to address diving barotrauma (pressure-induced injury related to an air space) to the head, face and oral regions, as well as scuba mouthpiece-related oral conditions. The relevant conditions for dentists who treat divers include diving-associated headache (migraine, tension-type headache), barosinusitis and barotitis-media (sinus and middle ear barotrauma, respectively), neuropathy, trigeminal (CN V) or facial (CN VII) nerve baroparesis (pressure-induced palsy), dental barotrauma (barometric-related tooth injury), barodontalgia (barometric-related dental pain), mouthpiece-associated herpes infection, pharyngeal gag reflex and temporomandibular joint disorder (dysfunction). For each condition, a theoretical description is followed by practical recommendations for the dental practitioner for the prevention and management of the condition.

  7. The silent witness: using dive computer records in diving fatality investigations.

    PubMed

    Sayer, Martin D J; Azzopardi, Elaine

    2014-09-01

    Downloaded data from diving computers can offer invaluable insights into diving incidents resulting in fatalities. Such data form an essential part of subsequent investigations or in legal actions related to the diving incident. It is often tempting to accept the information being displayed from a computer download without question. However, there is a large variability between the makes and models of dive computer in how the data are recorded, stored and re-displayed and caution must be employed in the interpretation of the evidence. In reporting on downloaded data, investigators should be fully aware of the limitations in the data retrieved. They should also know exactly how to interpret parameters such as: the accuracy of the dive profile; the effects of different mode settings; the precision of displayed water temperatures; the potential for misrepresenting breathing rates where there are data from integrated monitoring systems, and be able to challenge some forms of displayed information either through re-modelling based on the pressure/time profiles or by testing the computers in standardised conditions. PMID:25311326

  8. The silent witness: using dive computer records in diving fatality investigations.

    PubMed

    Sayer, Martin D J; Azzopardi, Elaine

    2014-09-01

    Downloaded data from diving computers can offer invaluable insights into diving incidents resulting in fatalities. Such data form an essential part of subsequent investigations or in legal actions related to the diving incident. It is often tempting to accept the information being displayed from a computer download without question. However, there is a large variability between the makes and models of dive computer in how the data are recorded, stored and re-displayed and caution must be employed in the interpretation of the evidence. In reporting on downloaded data, investigators should be fully aware of the limitations in the data retrieved. They should also know exactly how to interpret parameters such as: the accuracy of the dive profile; the effects of different mode settings; the precision of displayed water temperatures; the potential for misrepresenting breathing rates where there are data from integrated monitoring systems, and be able to challenge some forms of displayed information either through re-modelling based on the pressure/time profiles or by testing the computers in standardised conditions.

  9. Deadly diving? Physiological and behavioural management of decompression stress in diving mammals.

    PubMed

    Hooker, S K; Fahlman, A; Moore, M J; de Soto, N Aguilar; de Quirós, Y Bernaldo; Brubakk, A O; Costa, D P; Costidis, A M; Dennison, S; Falke, K J; Fernandez, A; Ferrigno, M; Fitz-Clarke, J R; Garner, M M; Houser, D S; Jepson, P D; Ketten, D R; Kvadsheim, P H; Madsen, P T; Pollock, N W; Rotstein, D S; Rowles, T K; Simmons, S E; Van Bonn, W; Weathersby, P K; Weise, M J; Williams, T M; Tyack, P L

    2012-03-22

    Decompression sickness (DCS; 'the bends') is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N(2)) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N(2) tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N(2) loading to management of the N(2) load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.

  10. Deadly diving? Physiological and behavioural management of decompression stress in diving mammals

    PubMed Central

    Hooker, S. K.; Fahlman, A.; Moore, M. J.; Aguilar de Soto, N.; Bernaldo de Quirós, Y.; Brubakk, A. O.; Costa, D. P.; Costidis, A. M.; Dennison, S.; Falke, K. J.; Fernandez, A.; Ferrigno, M.; Fitz-Clarke, J. R.; Garner, M. M.; Houser, D. S.; Jepson, P. D.; Ketten, D. R.; Kvadsheim, P. H.; Madsen, P. T.; Pollock, N. W.; Rotstein, D. S.; Rowles, T. K.; Simmons, S. E.; Van Bonn, W.; Weathersby, P. K.; Weise, M. J.; Williams, T. M.; Tyack, P. L.

    2012-01-01

    Decompression sickness (DCS; ‘the bends’) is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N2 loading to management of the N2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years. PMID:22189402

  11. Inner ear barotrauma from scuba diving.

    PubMed

    Sheridan, M F; Hetherington, H H; Hull, J J

    1999-03-01

    Inner ear barotrauma among scuba divers is believed to be caused by any of three conditions: a hemorrhage in the inner ear, a tear of the labyrinthine membrane, or a perilymphatic fistula. These injuries may occur concurrently or separately. Hemorrhage and membrane rupture are managed conservatively, while fistula requires surgical repair. In this report, we describe three cases of inner ear barotrauma in scuba divers. We also discuss the proposed etiologies of this injury and the controversy over whether or not divers who have suffered an inner ear trauma can safely resume scuba diving. Although the older literature clearly suggests otherwise, we believe that scuba divers who completely recover from inner (or middle) ear barotrauma may return to diving as long as they exercise caution and care.

  12. Oxygen toxicity in recreational and technical diving.

    PubMed

    Fock, Andrew; Millar, Ian

    2008-06-01

    It is increasingly common for recreational scuba divers to use breathing mixtures enriched with additional oxygen ('nitrox' or 'enriched air nitrogen') and for technical divers to be exposed to elevated partial pressures of oxygen for prolonged periods of time. The National Oceanic and Atmospheric Administration oxygen exposure limits have traditionally been used by the recreational diving industry and technical diving communities. Review of the original research into oxygen toxicity brings into question the validity of these limits and would suggest revised limits with a maximum partial pressure of oxygen of 162 kPa (1.6 Ata) and 142 kPa (1.4 Ata) at depth and the use of the repetitive air excursion (REPEX) limits for single and repetitive exposures. Suitable conservatism in case of the need for recompression therapy is recommended.

  13. Scuba diving enhances endogenous antioxidant defenses in lymphocytes and neutrophils.

    PubMed

    Ferrer, M D; Sureda, A; Batle, J M; Tauler, P; Tur, J A; Pons, A

    2007-03-01

    The aim was to study the effects of a scuba diving session on the lymphocyte antioxidant system, NO synthesis, the capability to produce reactive oxygen species and the antioxidant response in neutrophils. For that purpose seven male divers performed an immersion at a depth of 40 m for 25 min. The same parameters were measured after an hyperbaric oxygen (HBO) treatment at resting conditions in a hyperbaric chamber. Lymphocyte H2O2 production rose after diving and after HBO treatment. Glutathione peroxidase (GPx) and catalase activities increased after diving in lymphocytes, while after HBO exposure only increased GPx activity. Lymphocyte HO-1 mRNA expression increased after diving and after HBO exposure, while iNOS levels and nitrite levels significantly increased after diving. The hyperoxia associated to scuba diving leads to a condition of oxidative stress with increased lymphocyte H2O2 production, HO-1 expression, NO synthesis and antioxidant enzyme adaptations in order to avoid oxidative damage.

  14. Temporomandibular dysfunction syndrome associated with scuba diving mouthpieces.

    PubMed

    Hobson, R S

    1991-03-01

    As previous reports have highlighted that temporomandibular joint dysfunction syndrome can occur during scuba diving due to the use of a diving mouthpiece, 74 divers of varied experience (62 male, 12 female) were asked to evaluate the efficiency of the mouthpiece for the ease of grip, insertion into the mouth, clearing of water, air sharing, comfort and overall efficiency. They also recorded the level of muscle and joint discomfort experienced during diving and non-diving activities. The results indicate that temporomandibular joint problems unrelated to diving are compounded by the use of a diving mouthpiece. The diver's assessment of muscle tension and comfort while using the mouthpiece was found to be a good predictor of whether temporomandibular dysfunction would occur and the assessment scores have been used in a formula to aid selection of a mouthpiece.

  15. Sphenoid sinus barotrauma after scuba diving.

    PubMed

    Jeong, Jin Hyeok; Kim, Kuk; Cho, Seok Hyun; Kim, Kyung Rae

    2012-01-01

    We report the case of an 18-year-old male patient operated on for sphenoid sinus barotrauma after scuba diving. The patient attended our emergency department because of intractable headache but did not improve with conservative treatment. After computed tomography and magnetic resonance imaging examination, he was diagnosed with sphenoid sinusitis that extended to the nasal septum. He therefore underwent surgery for sinus ventilation and abscess drainage.

  16. Skin diving fatalities in New Zealand.

    PubMed

    Lewis, P R

    1979-06-27

    A review of skin diving fatalities in New Zealand for the period 1961--1973 revealed 28 deaths of which 21 were scuba divers. Two-thirds of the scuba deaths occurred in water less than 15m deep. Running out of air and lack of essential equipment were frequent contributory factors. The pathological findings are presented and show drowning to be the most common mode of death. Some deficiences in the assessment of these fatalities are discussed.

  17. [Barotraumatic cerebral air embolism following scuba diving].

    PubMed

    Nakao, N; Moriwaki, H; Oiwa, Y

    1990-11-01

    The authors report a case of barotraumatic cerebral air embolism following scuba diving, in which air embolism was diagnosed by CT. This kind of disorder becomes more frequent with the greater popularity of scuba diving. A healthy 24-year old woman made a rapid ascent with breath hold after a scuba dive to 8 meters for 20 minutes. On surfacing, she felt chest pain radiating to the cervical region. Shortly thereafter, she developed visual obscuration and weakness in the right arm and leg. On admission, neurological examination revealed right hemiparesis with hemisensory disturbance. Visual acuity was counting fingers at 1 meter in the right eye and only perception of hand movement in the left. CT obtained 10 hours after the onset revealed no abnormality except for a small area of air density. A chest x-ray film revealed mediastinal emphysema tracking into the neck. T2-weighted MRI 22 hours after the onset revealed multiple areas of high intensity, suggesting ischemic lesions, in the left hemispheric white matter. The visual disturbance, probably due to air embolism in the retinal vessels, was gradually improved and completely disappeared 24 hours after the onset. Nevertheless, there was no change in the motor and sensory disturbance of the extremities. The patient was transferred to an institution with hyperbaric facilities and was given hyperbaric oxygen therapy 30 hours after the accident with almost complete recovery of neurological function.

  18. Fatal Cervical Spine Injury From Diving Accident.

    PubMed

    Voland, Christelle; Vilarino, Raquel; Grabherr, Silke; Lobrinus, Johannes Alexander; Palmiere, Cristian

    2015-09-01

    Spinal cord injuries result after diving into shallow water, often after incautious jumps head first into water of unknown depth during recreational or sport activities. Mortality is generally due to upper cervical trauma. The authors present a case of a diving-related death in a young woman who underwent medicolegal investigations. The measured water depth at the supposed dive site was 1.40 m. Postmortem radiology and autopsy revealed fractures of the body and the posterior arch of the fifth cervical vertebra, a fracture of the right transverse process of the sixth cervical vertebra and hemorrhages involving the cervical paraspinal muscles. Neuropathology showed a posterior epidural hematoma involving the whole cervical region and a symmetric laceration of the spinal cord located at the fourth and fifth cervical vertebra level, surrounded by multiple petechial hemorrhages. Toxicology revealed the presence of ethanol in both blood and urine samples. The death was attributed to cervical spine fracture (C5-C6), spinal cord contusion, and subsequent drowning. This case highlights the usefulness of postmortem radiology, examination of the deep structures of the neck, toxicology, neuropathology, and a detailed research of signs of drowning to formulate appropriate hypotheses pertaining to the cause and mechanism of death.

  19. The epidemiology of murder and suicide involving scuba diving.

    PubMed

    Buzzacott, Peter; Denoble, Petar

    2012-01-01

    Murder and suicide in involving scuba are extremely rare. A systematic search identified 19 published studies describing 4,339 recreational diving fatalities occurring between 1956 and 2011. Case vignettes identified three possible murders and eight likely suicides. These are summarised and the victims' demography described. Prevalences of 69 murders per 105 diving fatalities and 184 suicides per 105 diving fatalities are lower than found among all cause mortality in the USA and Australia.

  20. Scuba diving post-bleomycin therapy: a case report.

    PubMed

    Gray, Richard N

    2010-01-01

    Though there are theoretical risks to scuba diving after undergoing chemotherapy with bleomycin, this case report demonstrates that it may be done without obvious injury if one takes adequate precautions. In this case, one year was allowed to elapse prior to a return to diving. Subsequently 52 dives have been accomplished with no observable adverse effects. Studies are recommended to determine what precautions should be instituted.

  1. Fabrication of a custom diving mouthpiece using a thermoforming material.

    PubMed

    Matsui, Ryosuke; Ueno, Toshiaki; Ohyama, Takashi

    2004-10-01

    Scuba divers may suffer from temporomandibular joint dysfunction and related problems associated with the use of commercially available diving mouthpieces. Several authors have recommended that custom diving mouthpieces be fabricated for relieving the symptoms of diver's mouth syndrome. The lost wax technique is commonly used for this purpose but may be time-consuming and is technically complicated. This article describes a simplified technique using thermoforming material for fabricating a custom diving mouthpiece.

  2. [Scuba diving: barotrauma, decompression sickness, pulmonary contra-indications].

    PubMed

    Héritier, F; Russi, E

    1993-02-01

    The practice of scuba diving is associated with two specific medical problems: barotrauma directly related to changes in ambient pressure, and decompression sickness related to the uptake and the release of inert gases by the body. Neurological symptoms are frequent in severe diving accidents. They may arise following either barotrauma or decompression sickness, and often require urgent treatment in a hyperbaric chamber. Asthma, chronic obstructive pulmonary disease, and spontaneous pneumothorax increase the risk of lung barotrauma and represent contraindications to diving.

  3. Life support maintenance for deep-sea diving

    SciTech Connect

    Nuckols, M.L.

    1987-01-01

    A treatise on life support maintenance in diving for the retrieval of radioactively contaminated, submerged materials should include discussions of gas supply requirements, carbon dioxide removal techniques, thermal protection, humidity control, and power sources. For the sake of brevity, this paper highlight only those areas peculiar to deep-sea diving and introduce a design aid being used in the development of new diving life support systems.

  4. Diving patterns of ama divers of Hegura Island, Japan.

    PubMed

    Mohri, M; Torii, R; Nagaya, K; Shiraki, K; Elsner, R; Takeuchi, H; Park, Y S; Hong, S K

    1995-06-01

    Daily diving patterns, especially depth-time profiles, were continuously recorded during the entire work shift in four cachido and four funado divers of Hegura Island, Japan. All Hegura divers (cachido and funado alike) were female and habitually wore wet suits. Cachidos dive free and unassisted from a boat or float, whereas funado divers are assisted by weighted descent and during the ascent by being pulled by a partner into a boat on the water surface. Both funado and cachido divers spent 250-280 min/day on the sea at their diving locations; the actual diving time was 100-120 min. The divers made 90-120 dives/day to a depth of 13-22 m, each dive lasting approximately 60 s, considerably longer and deeper than those observed and recorded previously in ama divers in the Chiba and Miura regions. These dive profiles are similar to those reported by Paulev in which he observed apparent signs of decompression sickness when the subject dived to a depth of 15-20 m 100 times in 5 h. The average bottom time for each dive of Hegura funados was 23.6 s which is approximately 10 s longer than that of Korean female ama. The rate of ascent in the funado divers was 1.5 m/s, which is nearly twice that of the cachido divers (0.8 m/s). The dive frequency of Hegura funados (109 dives/day) was greater than the Chiba male funados (23 dives/day). Accordingly, cumulative bottom time of Hegura funado was 48 min/day, whereas that of Chiba funado was 17 min/day.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. 29 CFR Appendix C to Subpart T of... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive-decompression computer uses the no-decompression limits specified in paragraph 5(a) of this appendix, and... first-aid and administering O2 treatment, are available at the dive site to treat diving-related...

  6. 29 CFR Appendix C to Subpart T of... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive-decompression computer uses the no-decompression limits specified in paragraph 5(a) of this appendix, and... first-aid and administering O2 treatment, are available at the dive site to treat diving-related...

  7. 29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive-decompression computer uses the no-decompression limits specified in paragraph 5(a) of this appendix, and... first-aid and administering O2 treatment, are available at the dive site to treat diving-related...

  8. 29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... permit a diver to use a dive-decompression computer designed to regulate decompression when the dive-decompression computer uses the no-decompression limits specified in paragraph 5(a) of this appendix, and... first-aid and administering O2 treatment, are available at the dive site to treat diving-related...

  9. Engineering of betabellin 14D: disulfide-induced folding of a beta-sheet protein.

    PubMed Central

    Yan, Y.; Erickson, B. W.

    1994-01-01

    The betabellin target structure consists of 2 32-residue beta sheets packed against each other by hydrophobic interactions. We have designed, chemically synthesized, and biophysically characterized betabellin 14S, a single chain, and betabellin 14D, the disulfide-bridged double chain. The 32-residue nongenetic betabellin-14 chain (HSLTASIkaLTIHVQakTATCQVkaYTVHISE, a = D-Ala, k = D-Lys) has a palindromic pattern of polar (p), nonpolar (n), end (e), and beta-turn (t,r) residues (epnpnpnttnpnpnprrpnpnpnttnpnpnpe). Each half contains the same 14-residue palindromic pattern (underlined). Pairs of D-amino acid residues are used to favor formation of inverse-common (type-I') beta turns. In water at pH 6.5, the single chain of betabellin 14S is not folded, but the disulfide-linked betabellin 14D is folded into a stable beta-sheet structure. Thus, folding of the covalent dimer beta-bellin 14D is induced by formation of the single interchain disulfide bond. The binary pattern of alternating polar and nonpolar residues of its beta-sheets is not sufficient to induce folding. Betabellin 14D is a very water-soluble (10 mg/mL), small (64 residues), nongenetic (12 D residues) beta-sheet protein with properties (well-dispersed proton NMR resonances; Tm = 58 degrees C and delta Hm = 106 kcal/mol at pH 5.5) like those of a native protein structure. PMID:7920252

  10. Gait switches in deep-diving beaked whales: biomechanical strategies for long-duration dives.

    PubMed

    Martín López, Lucía Martina; Miller, Patrick J O; Aguilar de Soto, Natacha; Johnson, Mark

    2015-05-01

    Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In addition to continuous stroking and stroke-and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorso-ventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise ∼80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth.

  11. Gait switches in deep-diving beaked whales: biomechanical strategies for long-duration dives.

    PubMed

    Martín López, Lucía Martina; Miller, Patrick J O; Aguilar de Soto, Natacha; Johnson, Mark

    2015-05-01

    Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In addition to continuous stroking and stroke-and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorso-ventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise ∼80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth. PMID:25954042

  12. SCUBA medicine: a first-responder's guide to diving injuries.

    PubMed

    Salahuddin, Moin; James, Laurie A; Bass, Evan Stuart

    2011-01-01

    Self-contained underwater breathing apparatus (SCUBA) diving is an ever-growing sport, and despite a myriad of technological advances to improve safety, it remains dangerous. Providers of medical care for SCUBA divers must have an understanding of diving physiology and potential medical problems that can occur. SCUBA diving also can take participants to remote areas, so being properly prepared for potential emergencies can make a significant difference. The following is a review of diving physiology and the medical problems that can occur in SCUBA divers, along with some suggestions as to how to prepare for a SCUBA excursion.

  13. Dive behaviour can predict metabolic expenditure in Steller sea lions.

    PubMed

    Goundie, Elizabeth T; Rosen, David A S; Trites, Andrew W

    2015-01-01

    Quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. However, estimating the costs of foraging is difficult for breath-hold divers, such as Steller sea lions, that feed underwater. We developed models parameterized with data from free-diving captive Steller sea lions to estimate the costs incurred by wild animals while foraging. We measured diving metabolic rate of trained sea lions performing four types of dives to 10 and 40 m in the open ocean and estimated the separate costs of different dive components: surface time; bottom time; and transiting to and from depth. We found that the sea lions' diving metabolic rates were higher while transiting (20.5 ± 13.0 ml O2 min(-1) kg(-1)) than while swimming at depth (13.5 ± 4.1 ml O2 min(-1) kg(-1)), and both were higher than metabolism at the surface (9.2 ± 1.6 ml O2 min(-1) kg(-1)). These values were incorporated into an energetic model that accurately predicted oxygen consumption for dives only (within 9.5%) and dive cycles (within 7.7%), although it consistently overestimated costs by 5.9% for dives and 21.8% for dive cycles. Differences in the costs of individual components of dives also explained differences in the efficiency of different dive strategies. Single dives were energetically less costly than bout dives; however, sea lions were more efficient at replenishing oxygen stores after bout dives and could therefore spend a greater portion of their time foraging than when undertaking single dives. The metabolic rates we measured for the different behavioural components of diving can be applied to time-depth recordings from wild Steller sea lions to estimate the energy expended while foraging. In turn, this can be used to understand how changes in prey availability affect energy balance and the health of individuals in

  14. Dive behaviour can predict metabolic expenditure in Steller sea lions

    PubMed Central

    Goundie, Elizabeth T.; Rosen, David A. S.; Trites, Andrew W.

    2015-01-01

    Quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. However, estimating the costs of foraging is difficult for breath-hold divers, such as Steller sea lions, that feed underwater. We developed models parameterized with data from free-diving captive Steller sea lions to estimate the costs incurred by wild animals while foraging. We measured diving metabolic rate of trained sea lions performing four types of dives to 10 and 40 m in the open ocean and estimated the separate costs of different dive components: surface time; bottom time; and transiting to and from depth. We found that the sea lions' diving metabolic rates were higher while transiting (20.5 ± 13.0 ml O2 min−1 kg−1) than while swimming at depth (13.5 ± 4.1 ml O2 min−1 kg−1), and both were higher than metabolism at the surface (9.2 ± 1.6 ml O2 min−1 kg−1). These values were incorporated into an energetic model that accurately predicted oxygen consumption for dives only (within 9.5%) and dive cycles (within 7.7%), although it consistently overestimated costs by 5.9% for dives and 21.8% for dive cycles. Differences in the costs of individual components of dives also explained differences in the efficiency of different dive strategies. Single dives were energetically less costly than bout dives; however, sea lions were more efficient at replenishing oxygen stores after bout dives and could therefore spend a greater portion of their time foraging than when undertaking single dives. The metabolic rates we measured for the different behavioural components of diving can be applied to time–depth recordings from wild Steller sea lions to estimate the energy expended while foraging. In turn, this can be used to understand how changes in prey availability affect energy balance and the health of individuals in

  15. Scuba diving-induced pulmonary edema in a swimming pool.

    PubMed

    Gnadinger, C A; Colwell, C B; Knaut, A L

    2001-11-01

    SCUBA diving-induced pulmonary edema is a rare syndrome that has been previously reported to occur in cold water. We present a case of SCUBA diving-induced pulmonary edema in a 52-year-old man diving in a warm swimming pool. The pathophysiology of this syndrome is unclear, but it is unrelated to either barotrauma or decompression illness. This patient developed frank pulmonary edema while submerged, which resolved after surfacing. As with other patients who have had this syndrome, he did not have any cardiorespiratory disease. The presentation and pathophysiology of SCUBA diving-induced pulmonary edema are discussed.

  16. Energetic costs of surface swimming and diving of birds.

    PubMed

    Butler, P J

    2000-01-01

    The energetic costs of swimming at the surface (swimming) and swimming underwater (diving) are compared in tufted ducks (Aythya fuligula) and three species of penguins, the gentoo (Pygoscelis papua), the king (Aptenodytes patagonicus), and the emperor (Aythya forsteri). Ducks swim on the surface and use their webbed feet as paddles, whereas penguins tend to swim just below the surface and use their flippers as hydrofoils, the latter being much more efficient. Penguins are more streamlined in shape. Thus, the amount of energy required to transport a given mass of bird a given distance (known as the cost of transport) is some two to three times greater in ducks than in penguins. Ducks are also very buoyant, and overcoming the force of buoyancy accounts for 60% and 85% of the cost of descent and remaining on the bottom, respectively, in these birds. The energy cost of a tufted duck diving to about 1.7 m is similar to that when it is swimming at its maximum sustainable speed at the surface (i.e., approximately 3.5 times the value when resting on water). Nonetheless, because of the relatively short duration of its dives, the tufted duck dives well within its calculated aerobic dive limit (cADL, usable O(2) stores per rate of O(2) usage when underwater). However, these three species of penguins have maximum dive durations ranging from 5 min to almost 16 min and maximum dive depths from 155 to 530 m. When these birds dive, they have to metabolise at no more than when resting in water in order for cADL to encompass the duration of most of their natural dives. In gentoo and king penguins, there is a fall in abdominal temperature during bouts of diving; this may reduce the oxygen requirements in the abdominal region, thus enabling dive duration to be extended further than would otherwise be the case. PMID:11121344

  17. Effect of recreational diving on Patagonian rocky reefs.

    PubMed

    Bravo, Gonzalo; Márquez, Federico; Marzinelli, Ezequiel M; Mendez, María M; Bigatti, Gregorio

    2015-03-01

    Tourism has grown considerably in the last decades, promoting activities such as recreational SCUBA diving that may affect marine benthic communities. In Puerto Madryn, Patagonia Argentina, sub-aquatic tourism areas (STA) receive about 7,000 divers per year. Diving is concentrated on a few small rocky reefs and 50% of the dives occur in summer. In this work, we evaluated the effect of recreational diving activities on benthic communities and determined whether diving causes a press (long-term) or a pulse (short-term) response. We quantified the percentage cover of benthic organisms and compared benthic assemblage structure and composition between two sites with contrasting usage by divers, 'highly disturbed' and 'moderately disturbed' sites, and two 'control' sites with similar physical characteristics but no diving activity, twice before and after the diving peak in summer. We found differences in benthic assemblage structure (identity and relative abundance of taxa) and composition (identity only) among diving sites and controls. These differences were consistent before and after the peak of diving in summer, suggesting that recreational diving may produce a press impact on overall benthic assemblage structure and composition in these STA. At the moderately disturbed site, however, covers of specific taxa, such as some key habitat-forming or highly abundant species, usually differed from those in controls only immediately after summer, after which they begun to resemble controls, suggesting a pulse impact. Thus, STA in Golfo Nuevo seem to respond differently to disturbances of diving depending on the usage of the sites. This information is necessary to develop sound management strategies in order to preserve local biodiversity. PMID:25577688

  18. Yet More Visualized JAMSTEC Cruise and Dive Information

    NASA Astrophysics Data System (ADS)

    Tomiyama, T.; Hase, H.; Fukuda, K.; Saito, H.; Kayo, M.; Matsuda, S.; Azuma, S.

    2014-12-01

    Every year, JAMSTEC performs about a hundred of research cruises and numerous dive surveys using its research vessels and submersibles. JAMSTEC provides data and samples obtained during these cruises and dives to international users through a series of data sites on the Internet. The "DARWIN (http://www.godac.jamstec.go.jp/darwin/e)" data site disseminates cruise and dive information. On DARWIN, users can search interested cruises and dives with a combination search form or an interactive tree menu, and find lists of observation data as well as links to surrounding databases. Document catalog, physical sample databases, and visual archive of dive surveys (e. g. in http://www.godac.jamstec.go.jp/jmedia/portal/e) are directly accessible from the lists. In 2014, DARWIN experienced an update, which was arranged mainly for enabling on-demand data visualization. Using login users' functions, users can put listed data items into the virtual basket and then trim, plot and download the data. The visualization tools help users to quickly grasp the quality and characteristics of observation data. Meanwhile, JAMSTEC launched a new data site named "JDIVES (http://www.godac.jamstec.go.jp/jdives/e)" to visualize data and sample information obtained by dive surveys. JDIVES shows tracks of dive surveys on the "Google Earth Plugin" and diagrams of deep-sea environmental data such as temperature, salinity, and depth. Submersible camera images and links to associated databases are placed along the dive tracks. The JDVIES interface enables users to perform so-called virtual dive surveys, which can help users to understand local geometries of dive spots and geological settings of associated data and samples. It is not easy for individual researchers to organize a huge amount of information recovered from each cruise and dive. The improved visibility and accessibility of JAMSTEC databases are advantageous not only for second-hand users, but also for on-board researchers themselves.

  19. Energetic costs of surface swimming and diving of birds.

    PubMed

    Butler, P J

    2000-01-01

    The energetic costs of swimming at the surface (swimming) and swimming underwater (diving) are compared in tufted ducks (Aythya fuligula) and three species of penguins, the gentoo (Pygoscelis papua), the king (Aptenodytes patagonicus), and the emperor (Aythya forsteri). Ducks swim on the surface and use their webbed feet as paddles, whereas penguins tend to swim just below the surface and use their flippers as hydrofoils, the latter being much more efficient. Penguins are more streamlined in shape. Thus, the amount of energy required to transport a given mass of bird a given distance (known as the cost of transport) is some two to three times greater in ducks than in penguins. Ducks are also very buoyant, and overcoming the force of buoyancy accounts for 60% and 85% of the cost of descent and remaining on the bottom, respectively, in these birds. The energy cost of a tufted duck diving to about 1.7 m is similar to that when it is swimming at its maximum sustainable speed at the surface (i.e., approximately 3.5 times the value when resting on water). Nonetheless, because of the relatively short duration of its dives, the tufted duck dives well within its calculated aerobic dive limit (cADL, usable O(2) stores per rate of O(2) usage when underwater). However, these three species of penguins have maximum dive durations ranging from 5 min to almost 16 min and maximum dive depths from 155 to 530 m. When these birds dive, they have to metabolise at no more than when resting in water in order for cADL to encompass the duration of most of their natural dives. In gentoo and king penguins, there is a fall in abdominal temperature during bouts of diving; this may reduce the oxygen requirements in the abdominal region, thus enabling dive duration to be extended further than would otherwise be the case.

  20. Diving through the thermal window: implications for a warming world

    PubMed Central

    Campbell, Hamish A.; Dwyer, Ross G.; Gordos, Matthew; Franklin, Craig E.

    2010-01-01

    Population decline and a shift in the geographical distribution of some ectothermic animals have been attributed to climatic warming. Here, we show that rises in water temperature of a few degrees, while within the thermal window for locomotor performance, may be detrimental to diving behaviour in air-breathing ectotherms (turtles, crocodilians, marine iguanas, amphibians, snakes and lizards). Submergence times and internal and external body temperature were remotely recorded from freshwater crocodiles (Crocodylus johnstoni) while they free-ranged throughout their natural habitat in summer and winter. During summer, the crocodiles' mean body temperature was 5.2 ± 0.1°C higher than in winter and the largest proportion of total dive time was composed of dive durations approximately 15 min less than in winter. Diving beyond 40 min during summer required the crocodiles to exponentially increase the time they spent on the surface after the dive, presumably to clear anaerobic debt. The relationship was not as significant in winter, even though a greater proportion of dives were of a longer duration, suggesting that diving lactate threshold (DLT) was reduced in summer compared with winter. Additional evidence for a reduced DLT in summer was derived from the stronger influence body mass exerted upon dive duration, compared to winter. The results demonstrate that the higher summer body temperature increased oxygen demand during the dive, implying that thermal acclimatization of the diving metabolic rate was inadequate. If the study findings are common among air-breathing diving ectotherms, then long-term warming of the aquatic environment may be detrimental to behavioural function and survivorship. PMID:20610433

  1. Effect of recreational diving on Patagonian rocky reefs.

    PubMed

    Bravo, Gonzalo; Márquez, Federico; Marzinelli, Ezequiel M; Mendez, María M; Bigatti, Gregorio

    2015-03-01

    Tourism has grown considerably in the last decades, promoting activities such as recreational SCUBA diving that may affect marine benthic communities. In Puerto Madryn, Patagonia Argentina, sub-aquatic tourism areas (STA) receive about 7,000 divers per year. Diving is concentrated on a few small rocky reefs and 50% of the dives occur in summer. In this work, we evaluated the effect of recreational diving activities on benthic communities and determined whether diving causes a press (long-term) or a pulse (short-term) response. We quantified the percentage cover of benthic organisms and compared benthic assemblage structure and composition between two sites with contrasting usage by divers, 'highly disturbed' and 'moderately disturbed' sites, and two 'control' sites with similar physical characteristics but no diving activity, twice before and after the diving peak in summer. We found differences in benthic assemblage structure (identity and relative abundance of taxa) and composition (identity only) among diving sites and controls. These differences were consistent before and after the peak of diving in summer, suggesting that recreational diving may produce a press impact on overall benthic assemblage structure and composition in these STA. At the moderately disturbed site, however, covers of specific taxa, such as some key habitat-forming or highly abundant species, usually differed from those in controls only immediately after summer, after which they begun to resemble controls, suggesting a pulse impact. Thus, STA in Golfo Nuevo seem to respond differently to disturbances of diving depending on the usage of the sites. This information is necessary to develop sound management strategies in order to preserve local biodiversity.

  2. Scanning sonar of rolling porpoises during prey capture dives.

    PubMed

    Akamatsu, T; Wang, D; Wang, K; Li, S; Dong, S

    2010-01-01

    Dolphins and porpoises have excellent biosonar ability, which they use for navigation, ranging and foraging. However, the role of biosonar in free-ranging small cetaceans has not been fully investigated. The biosonar behaviour and body movements of 15 free-ranging finless porpoises (Neophocaena phocaenoides) were observed using electronic tags attached to the animals. The porpoises often rotated their bodies more than 60 deg., on average, around the body axis in a dive bout. This behaviour occupied 31% of the dive duration during 186 h of effective observation time. Rolling dives were associated with extensive searching effort, and 23% of the rolling dive time was phonated, almost twice the phonation ratio of upright dives. Porpoises used short inter-click interval sonar 4.3 times more frequently during rolling dives than during upright dives. Sudden speed drops, which indicated that an individual turned around, occurred 4.5 times more frequently during rolling dives than during upright dives. Together, these data suggest that the porpoises searched extensively for targets and rolled their bodies to enlarge the search area by changing the narrow beam axis of the biosonar. Once a possible target was detected, porpoises frequently produced short-range sonar sounds. Continuous searching for prey and frequent capture trials appeared to occur during rolling dives of finless porpoises. In contrast, head movements ranging +/-2 cm, which can also change the beam axis, were regularly observed during both dives. Head movements might assist in instant assessment of the arbitrary direction by changing the beam axis rather than prey searching and pursuit.

  3. Diving through the thermal window: implications for a warming world.

    PubMed

    Campbell, Hamish A; Dwyer, Ross G; Gordos, Matthew; Franklin, Craig E

    2010-12-22

    Population decline and a shift in the geographical distribution of some ectothermic animals have been attributed to climatic warming. Here, we show that rises in water temperature of a few degrees, while within the thermal window for locomotor performance, may be detrimental to diving behaviour in air-breathing ectotherms (turtles, crocodilians, marine iguanas, amphibians, snakes and lizards). Submergence times and internal and external body temperature were remotely recorded from freshwater crocodiles (Crocodylus johnstoni) while they free-ranged throughout their natural habitat in summer and winter. During summer, the crocodiles' mean body temperature was 5.2±0.1°C higher than in winter and the largest proportion of total dive time was composed of dive durations approximately 15 min less than in winter. Diving beyond 40 min during summer required the crocodiles to exponentially increase the time they spent on the surface after the dive, presumably to clear anaerobic debt. The relationship was not as significant in winter, even though a greater proportion of dives were of a longer duration, suggesting that diving lactate threshold (DLT) was reduced in summer compared with winter. Additional evidence for a reduced DLT in summer was derived from the stronger influence body mass exerted upon dive duration, compared to winter. The results demonstrate that the higher summer body temperature increased oxygen demand during the dive, implying that thermal acclimatization of the diving metabolic rate was inadequate. If the study findings are common among air-breathing diving ectotherms, then long-term warming of the aquatic environment may be detrimental to behavioural function and survivorship. PMID:20610433

  4. Scuba diving is possible and safe for patients with haemophilia.

    PubMed

    Schved, J F; De Haro, M; Drapeau, M; Schved, M

    2012-01-01

    For a long time, physical activities have been contraindicated in haemophiliacs or were restricted to few activities. Sports are nowadays advocated for haemophiliacs. Although various lists of physical activities have been proposed, scuba diving is never mentioned. Thus, with a group of haemophilic volunteers, a study was launched on whether, with strict medical follow-up, scuba diving could be allowed for patients with haemophilia. All the participants followed a training program including theory and assessment. In 6 years, a total of 517 dives were performed by 20 patients with congenital bleeding disorders. Nine were under prophylaxis for haemophilia, and nine received on-demand treatment. Two patients had type I von Willebrand's disease. Among the 20 patients, 12 made 12-153 dives, whereas six made eight dives each. No incident was noted during or after the dives. Thus, scuba diving can be authorized for PWH, if they have none of the specific medical contraindications for diving and if they have received medical training allowing them to manage their disease themselves.

  5. Are the Risks of Sport Scuba Diving Being Underestimated?

    ERIC Educational Resources Information Center

    Roos, Robert

    1989-01-01

    A lawsuit has challenged the safety of the tables widely used in scuba diving. Other concerns also have emerged: A condition known as patent foramen ovale may increase the risk of decompression sickness, and studies are raising questions about the long-term effects of diving. (Author/JD)

  6. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  7. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  8. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  9. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  10. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  11. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.425 Surface-supplied air...

  12. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... § 1926.1076 Qualifications of dive team. Note: The requirements applicable to construction work...

  13. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  14. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  15. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... at depths less than 190 fsw, except that dives with bottom times of 30 minutes or less may be... is continuously tended while in the water; (d) When a diver is in a physically confining space... time greater than 120 minutes, except when the diver is using a heavy-weight diving outfit or is...

  16. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... at depths less than 190 fsw, except that dives with bottom times of 30 minutes or less may be... is continuously tended while in the water; (d) When a diver is in a physically confining space... time greater than 120 minutes, except when the diver is using a heavy-weight diving outfit or is...

  17. Recent modifications to the investigation of diving related deaths.

    PubMed

    Edmonds, Carl; Caruso, James

    2014-03-01

    The investigation of deaths that involve diving using a compressed breathing gas (SCUBA diving) is a specialized area of forensic pathology. Diving related deaths occur more frequently in certain jurisdictions, but any medical examiner or coroner's office may be faced with performing this type of investigation. In order to arrive at the correct conclusion regarding the cause and manner of death, forensic pathologists and investigators need to have a basic understanding of diving physiology, and should also utilize more recently developed technology and ancillary techniques. In the majority of diving related deaths, the cause of death is drowning, but this more often represents a final common pathway due to a water environment. The chain of events leading to the death is just as important to elucidate if similar deaths are to be minimized in the future. Re-enactment of accident scenarios, interrogation of dive computers, postmortem radiographic imaging, and slight alterations in autopsy technique may allow some of these diving related deaths to the better characterized. The amount and location of gas present in the body at the time of autopsy may be very meaningful or may simply represent a postmortem artifact. Medical examiners, coroners, and forensic investigators should consider employing select ancillary techniques to more thoroughly investigate the factors contributing a death associated with SCUBA diving. PMID:24166195

  18. Scuba Diving and Kinesiology: Development of an Academic Program

    ERIC Educational Resources Information Center

    Kovacs, Christopher R.; Walter, Daniel

    2015-01-01

    The use of scuba diving as a recreational activity within traditional university instructional programs has been well established. Departments focusing on kinesiology, physical education, or exercise science have often provided scuba diving lessons as part of their activity-based course offerings. However, few departments have developed an…

  19. Internal carotid artery dissection associated with scuba diving.

    PubMed

    Nelson, E E

    1995-01-01

    A 52-year-old man presented to the emergency department with dysphasia and a headache after scuba diving. He was treated initially for decompression sickness. Subsequent workup revealed bilateral internal carotid artery dissection. The risk factors, presenting symptoms, diagnosis, and treatment of internal carotid artery dissection are reviewed. The importance of considering unusual causes of neurologic deficits after scuba diving is emphasized.

  20. Scuba diving: What you and your patients need to know.

    PubMed

    McMullin, Ann Marie

    2006-08-01

    Self-contained underwater breathing apparatus (SCUBA) diving continues to gain popularity. General practitioners need to know the health requirements and contraindications so they can counsel patients appropriately. SCUBA diving injuries may not be apparent immediately and require knowledge and understanding for accurate diagnosis and treatment.

  1. Are the Risks of Sport Scuba Diving Being Underestimated?

    PubMed

    Roos, R

    1989-07-01

    A lawsuit has challenged the safety of the tables widely used in scuba diving. Other concerns also have emerged: A condition known as patent foramen ovale may increase the risk of decompression sickness, and studies are raising questions about the long-term effects of diving.

  2. Relationship between anxiety and performance in scuba diving.

    PubMed

    Griffiths, T J; Steel, D H; Vaccaro, P

    1979-06-01

    The present research examined the relationship between the anxiety levels of 62 beginning Scuba diving students and standardized performance tests from the Y.M.C.A. training program. Results suggested that there was no relationship between anxiety and performance on relatively simple tasks, while there was a relationship between anxiety and performance on the more complex diving maneuvers.

  3. Pulmonary barotrauma after a free dive--a possible mechanism.

    PubMed

    Kol, S; Weisz, G; Melamed, Y

    1993-03-01

    Pulmonary barotrauma during scuba diving is a life-threatening event. In a skin diver, who does not use compressed air, this complication is rare and its pathophysiology is not readily understood. We present a young, healthy skin diver who suffered pneumomediastinum and subcutaneous emphysema after a sequence of free dives to 5 m, and suggest a possible mechanism.

  4. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  5. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Post-dive procedures. Note: The requirements applicable to construction work under this section...

  6. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Post-dive procedures. Note: The requirements applicable to construction work under this section...

  7. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Post-dive procedures. Note: The requirements applicable to construction work under this section...

  8. 29 CFR 1910.423 - Post-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Post-dive procedures. 1910.423 Section 1910.423 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Post-dive procedures. (a) General. The employer shall comply with the following requirements which...

  9. 29 CFR 1910.423 - Post-dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Post-dive procedures. 1910.423 Section 1910.423 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Post-dive procedures. (a) General. The employer shall comply with the following requirements which...

  10. Diving and pregnancy: what do we really know?

    PubMed

    Conger, Jacqueline; Magann, Everett F

    2014-09-01

    Exercise during pregnancy has been advocated by many professional organizations to promote fetal heath and maternal well-being. Those same professional organizations do not recommend diving during pregnancy because of the potential adverse outcomes that have been observed in the animal model. In nonpregnant women, diving becomes problematic at depth as the ambient pressure increases and more gases become dissolved in the bloodstream. This can result in oxygen toxicity and nitrogen narcosis. Too rapid an ascent from depth can cause nitrogen emboli that can lodge in joints and tissue, resulting in decompression sickness, known as "the bends." The best animal model to study the effects of diving on pregnancy is the sheep model. Bubbling has been observed in both ewes and their fetuses, with bubbles more common in the ewes. Repeated decompressions done improperly can lead to fetal death. Information on pregnancy outcomes in humans is more limited, with inconsistent data on diving and birth defects, spontaneous abortions, and stillbirth. Even in the face of overall increased resistance in the maternal or fetal placental circulations, the total placental blood flow is usually maintained, preventing adverse outcomes. It appears that the safest choice during pregnancy is to avoid diving; however, if the woman dove when she did not know she was pregnant, there is usually a normal outcome. If a women insists on diving during pregnancy, she should go to a depth of only 60 ft, and duration of her dive should be half that recommended by Navy dive table times.

  11. Recent modifications to the investigation of diving related deaths.

    PubMed

    Edmonds, Carl; Caruso, James

    2014-03-01

    The investigation of deaths that involve diving using a compressed breathing gas (SCUBA diving) is a specialized area of forensic pathology. Diving related deaths occur more frequently in certain jurisdictions, but any medical examiner or coroner's office may be faced with performing this type of investigation. In order to arrive at the correct conclusion regarding the cause and manner of death, forensic pathologists and investigators need to have a basic understanding of diving physiology, and should also utilize more recently developed technology and ancillary techniques. In the majority of diving related deaths, the cause of death is drowning, but this more often represents a final common pathway due to a water environment. The chain of events leading to the death is just as important to elucidate if similar deaths are to be minimized in the future. Re-enactment of accident scenarios, interrogation of dive computers, postmortem radiographic imaging, and slight alterations in autopsy technique may allow some of these diving related deaths to the better characterized. The amount and location of gas present in the body at the time of autopsy may be very meaningful or may simply represent a postmortem artifact. Medical examiners, coroners, and forensic investigators should consider employing select ancillary techniques to more thoroughly investigate the factors contributing a death associated with SCUBA diving.

  12. Development of anxiety symptoms during a deep diving experiment.

    PubMed

    Abraini, J H; Ansseau, M; Martinez, E; Burnet, H; Wauthy, J; Lemaire, C

    Six commercial divers were investigated for anxiety responses during a 29-day, open-sea world record dive at 500 meters of depth. Three of six (50%) divers developed anxiety. The authors emphasize the importance of research on personality traits as possible predictors for the development of anxiety during deep dives of exceptional depth and duration of confinement.

  13. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  14. Exercise-induced myofibrillar disruption with sarcolemmal integrity prior to simulated diving has no effect on vascular bubble formation in rats.

    PubMed

    Jørgensen, Arve; Foster, Philip P; Eftedal, Ingrid; Wisløff, Ulrik; Paulsen, Gøran; Havnes, Marianne B; Brubakk, Alf O

    2013-05-01

    Decompression sickness is initiated by gas bubbles formed during decompression, and it has been generally accepted that exercise before decompression causes increased bubble formation. There are indications that exercise-induced muscle injury seems to be involved. Trauma-induced skeletal muscle injury and vigorous exercise that could theoretically injure muscle tissues before decompression have each been shown to result in profuse bubble formation. Based on these findings, we hypothesized that exercise-induced skeletal muscle injury prior to decompression from diving would cause increase of vascular bubbles and lower survival rates after decompression. In this study, we examined muscle injury caused by eccentric exercise in rats prior to simulated diving and we observed the resulting bubble formation. Female Sprague-Dawley rats (n = 42) ran downhill (-16º) for 100 min on a treadmill followed by 90 min rest before a 50-min simulated saturation dive (709 kPa) in a pressure chamber. Muscle injury was evaluated by immunohistochemistry and qPCR, and vascular bubbles after diving were detected by ultrasonic imaging. The exercise protocol resulted in increased mRNA expression of markers of muscle injury; αB-crystallin, NF-κB, and TNF-α, and myofibrillar disruption with preserved sarcolemmal integrity. Despite evident myofibrillar disruption after eccentric exercise, no differences in bubble amounts or survival rates were observed in the exercised animals as compared to non-exercised animals after diving, a novel finding that may be applicable to humans.

  15. The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function.

    PubMed

    Lozo, Mislav; Madden, Dennis; Gunjaca, Grgo; Ljubkovic, Marko; Marinovic, Jasna; Dujic, Zeljko

    2015-03-01

    Self-contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer-lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive. PMID:24528802

  16. The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function.

    PubMed

    Lozo, Mislav; Madden, Dennis; Gunjaca, Grgo; Ljubkovic, Marko; Marinovic, Jasna; Dujic, Zeljko

    2015-03-01

    Self-contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer-lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive.

  17. Dominance in cardiac parasympathetic activity during real recreational SCUBA diving.

    PubMed

    Chouchou, Florian; Pichot, Vincent; Garet, Martin; Barthélémy, Jean-Claude; Roche, Frédéric

    2009-06-01

    It was already established that exposure to hyperbaric conditions induces vagal-depended bradycardia but field study on autonomic nervous system (ANS) activity during self-contained underwater breathing apparatus (SCUBA) diving is lacking. The aim of the present study was to evaluate ANS modifications during real recreational SCUBA diving using heart rate variability analysis (timedomain, frequency-domain and Poincaré plot) in 10 experienced and volunteers recreational divers. Mean RR, root mean square of successive differences of interval (rMSSD), high frequency of spectral analysis and standard deviation 1 of Poincaré Plot increased (P < 0.05) during dive. Low frequency/high frequency ratio decreased during dive (P < 0.05) but increased after (P < 0.05). Recreational SCUBA diving induced a rise in vagal activity and a decrease in cardiac sympathetic activity. Conversely, sympathetic activity increases (P < 0.05) during the recovery.

  18. [Diving fitness of children and adolescents. Importance for ENT doctors].

    PubMed

    Tetzlaff, K; Muth, C M; Klingmann, C

    2008-05-01

    About 10% of all sport scuba divers are children and adolescents. Little is known about the particular risks and consequences of this sport on a child's health. Due to the peculiarities of childhood anatomy and physiology, certain restrictions apply to the diving fitness of children and adolescents. Before starting scuba training, the presence of particular cognitive abilities must be demonstrated and eustachian tube dysfunction must be ruled out by a specialist. Medical contra-indications to scuba diving for adults apply to children too but must be adapted. Relative risks for adults may translate to absolute contra-indications in children and adolescents. When planning dives, there should be rigorous limitations as to depth and time. Experienced adult divers must always assist with dive planning and accompany children and adolescents when scuba diving.

  19. The role of radiology in dive-related disorders.

    PubMed

    Carson, William K; Mecklenburg, Brian

    2005-01-01

    Recreational scuba diving has continued to grow in popularity in the past several decades, and military diving remains an integral part of ship husbandry, explosives and ordinance disposal, and special warfare. Although relatively uncommon, disorders such as decompression sickness and arterial gas embolism can be fatal, whereas disorders such as ear baro-trauma and dysbaric osteonecrosis are not fatal but can cause significant morbidity. An extensive literature search was performed to comprehensively examine the current role of diagnostic radiology with respect to diving medicine. In selected cases, diagnostic imaging can be of potential benefit for evaluation. Diagnostic imaging plays a useful role in the screening of certain individuals for future fitness to dive. Radiological imaging has also been of paramount importance in postmortem evaluation of dive casualties.

  20. [Before going on a diving holiday--consider this].

    PubMed

    Kemmer, A

    2004-02-19

    A prerequisite for all those who go in for the sport of scuba diving is mental and physical fitness. This must be checked within the framework of an examination for diving fitness before first taking up the sport, and should be rechecked every one to three years. For fitness for diving, not only lung function, ECG and tubal function need to be normal--the psychological profile of the holiday maker also plays an important role under water. For he or she must be able rapidly and reliably to recognize a dangerous situation and to react to it appropriately. Thorough training and the compliance with the rules of diving offer protection from many of the risks of this underwater sport--for example, problems with the ears or sinuses can be avoided. The most common cause of fatal diving accidents is a barotrauma of the lung with rupture of the alveoli on ascending.

  1. Tympanometric evaluation of middle ear barotrauma during recreational scuba diving.

    PubMed

    Green, S M; Rothrock, S G; Green, E A

    1993-10-01

    We report the first prospective evaluation of middle ear barotrauma in experienced recreational scuba divers. In this pilot study, tympanometric and otoscopic evaluations were performed daily on two experienced scuba divers engaged in multi-day repetitive diving. Middle ear pressures decreased in proportion to diving frequency, demonstrating eustachian tube dysfunction which promptly reversed upon cessation of diving Otoscopic evidence of traumatic injury to the middle ear occurred in proportion to diving frequency, and also readily reversed upon cessation of diving. Tympanic membrane compliance remained normal, often despite pronounced otoscopic abnormalities. Otologic symptoms and impairment of acuity were not observed. Tympanometry appears to be a valuable modality for the verification of middle ear hemorrhage or tympanic membrane rupture. This preliminary data should assist investigators in planning more comprehensive studies of middle ear barotrauma, including clinical trials of treatment and prophylactic interventions for this common condition.

  2. Dysbaric gas bubble disease in dogs. IV. Acclimatization to diving

    SciTech Connect

    Kunkle, T.D.; Morita, A.; Beckman, E.L.

    1986-01-01

    Acclimatization to diving was documented to occur in dogs. An increase in the number of repetitive dives which could be tolerated, as well as a decrease in the total number of pulmonary artery venous gas emboli resulting from individual dives were observed. The results from the experimental subject ''Jason'' indicate that acclimatization involves a reduction in the number of bubbles, and not an increase in the ability of the body to tolerate bubbles. Acclimatization is principally a physical rather than a physiological event. Bubbles forming in vivo must grow from nuclei of some sort. If these nuclei are stable, discrete structure that are destroyed when they grow into gross bubbles, then repetitive diving might markedly reduce by attrition the number of such bubble micronuclei. This would result in fewer bubbles being formed during subsequent dives, thus leading to the observed acclimatization effect. 7 refs., 3 figs., 4 tabs.

  3. CHST14/D4ST1 deficiency: New form of Ehlers-Danlos syndrome.

    PubMed

    Kosho, Tomoki

    2016-02-01

    Carbohydrate sulfotransferase 14/dermatan 4-O-sulfotransferase-1 (CHST14/D4ST1) deficiency represents a specific form of Ehlers-Danlos syndrome (EDS) caused by recessive loss-of-function mutations in CHST14. The disorder has been independently termed "adducted thumb-clubfoot syndrome", "EDS, Kosho type", and "EDS, musculocontractural type". To date, 31 affected patients from 21 families have been described. Clinically, CHST14/D4ST1 deficiency is characterized by multiple congenital malformations (craniofacial features including large fontanelle, hypertelorism, short and downslanting palpebral fissures, blue sclerae, short nose with hypoplastic columella, low-set and rotated ears, high palate, long philtrum, thin upper lip vermilion, small mouth, and micro-retrognathia; multiple congenital contractures including adduction-flexion contractures and talipes equinovarus as well as other visceral or ophthalmological malformations) and progressive multisystem fragility-related complications (skin hyperextensibility, bruisability, and fragility with atrophic scars; recurrent dislocations; progressive talipes or spinal deformities; pneumothorax or pneumohemothorax; large subcutaneous hematomas; and diverticular perforation). Etiologically, multisystem fragility is presumably caused by impaired assembly of collagen fibrils resulting from loss of dermatan sulfate (DS) in the decorin glycosaminoglycan side chain that promotes electrostatic binding between collagen fibrils. This is the first reported human disorder that specifically affects biosynthesis of DS. Its clinical characteristics indicate that CHST14/D4ST1 and, more fundamentally, DS, play a critical role in fetal development and maintenance of connective tissues in multiple organs. Considering that patients with CHST14/D4ST1 deficiency develop progressive multisystem fragility-related manifestations, establishment of a comprehensive and detailed natural history and health-care guidelines as well as further elucidation

  4. CHST14/D4ST1 deficiency: New form of Ehlers-Danlos syndrome.

    PubMed

    Kosho, Tomoki

    2016-02-01

    Carbohydrate sulfotransferase 14/dermatan 4-O-sulfotransferase-1 (CHST14/D4ST1) deficiency represents a specific form of Ehlers-Danlos syndrome (EDS) caused by recessive loss-of-function mutations in CHST14. The disorder has been independently termed "adducted thumb-clubfoot syndrome", "EDS, Kosho type", and "EDS, musculocontractural type". To date, 31 affected patients from 21 families have been described. Clinically, CHST14/D4ST1 deficiency is characterized by multiple congenital malformations (craniofacial features including large fontanelle, hypertelorism, short and downslanting palpebral fissures, blue sclerae, short nose with hypoplastic columella, low-set and rotated ears, high palate, long philtrum, thin upper lip vermilion, small mouth, and micro-retrognathia; multiple congenital contractures including adduction-flexion contractures and talipes equinovarus as well as other visceral or ophthalmological malformations) and progressive multisystem fragility-related complications (skin hyperextensibility, bruisability, and fragility with atrophic scars; recurrent dislocations; progressive talipes or spinal deformities; pneumothorax or pneumohemothorax; large subcutaneous hematomas; and diverticular perforation). Etiologically, multisystem fragility is presumably caused by impaired assembly of collagen fibrils resulting from loss of dermatan sulfate (DS) in the decorin glycosaminoglycan side chain that promotes electrostatic binding between collagen fibrils. This is the first reported human disorder that specifically affects biosynthesis of DS. Its clinical characteristics indicate that CHST14/D4ST1 and, more fundamentally, DS, play a critical role in fetal development and maintenance of connective tissues in multiple organs. Considering that patients with CHST14/D4ST1 deficiency develop progressive multisystem fragility-related manifestations, establishment of a comprehensive and detailed natural history and health-care guidelines as well as further elucidation

  5. Novel locomotor muscle design in extreme deep-diving whales.

    PubMed

    Velten, B P; Dillaman, R M; Kinsey, S T; McLellan, W A; Pabst, D A

    2013-05-15

    Most marine mammals are hypothesized to routinely dive within their aerobic dive limit (ADL). Mammals that regularly perform deep, long-duration dives have locomotor muscles with elevated myoglobin concentrations that are composed of predominantly large, slow-twitch (Type I) fibers with low mitochondrial volume densities (V(mt)). These features contribute to extending ADL by increasing oxygen stores and decreasing metabolic rate. Recent tagging studies, however, have challenged the view that two groups of extreme deep-diving cetaceans dive within their ADLs. Beaked whales (including Ziphius cavirostris and Mesoplodon densirostris) routinely perform the deepest and longest average dives of any air-breathing vertebrate, and short-finned pilot whales (Globicephala macrorhynchus) perform high-speed sprints at depth. We investigated the locomotor muscle morphology and estimated total body oxygen stores of several species within these two groups of cetaceans to determine whether they (1) shared muscle design features with other deep divers and (2) performed dives within their calculated ADLs. Muscle of both cetaceans displayed high myoglobin concentrations and large fibers, as predicted, but novel fiber profiles for diving mammals. Beaked whales possessed a sprinter's fiber-type profile, composed of ~80% fast-twitch (Type II) fibers with low V(mt). Approximately one-third of the muscle fibers of short-finned pilot whales were slow-twitch, oxidative, glycolytic fibers, a rare fiber type for any mammal. The muscle morphology of beaked whales likely decreases the energetic cost of diving, while that of short-finned pilot whales supports high activity events. Calculated ADLs indicate that, at low metabolic rates, both beaked and short-finned pilot whales carry sufficient onboard oxygen to aerobically support their dives.

  6. A Method for Identification of Some Components of Judging Springboard Diving.

    ERIC Educational Resources Information Center

    McCormick, James H.; And Others

    1982-01-01

    This study identifies critical elements of the front dive half-twist that judges are likely to look for when they score springboard diving competitions. Videotapes of divers at a 1979 intercollegiate diving meet were made and analyzed, using grid scoring procedures, to isolate components of the dives that would help predict judges' scores.…

  7. Diving and foraging patterns of Marbled Murrelets (Brachyramphus marmoratus): Testing predictions from optimal-breathing models

    USGS Publications Warehouse

    Jodice, Patrick G.; Collopy, M.W.

    1999-01-01

    The diving behavior of Marbled Murrelets (Brachyramphus marmoratus) was studied using telemetry along the Oregon coast during the 1995 and 1996 breeding seasons and examined in relation to predictions from optimal-breathing models. Duration of dives, pauses, dive bouts, time spent under water during dive bouts, and nondiving intervals between successive dive bouts were recorded. Most diving metrics differed between years but not with oceanographic conditions or shore type. There was no effect of water depth on mean dive time or percent time spent under water even though dive bouts occurred in depths from 3 to 36 m. There was a significant, positive relationship between mean dive time and mean pause time at the dive-bout scale each year. At the dive-cycle scale, there was a significant positive relationship between dive time and preceding pause time in each year and a significant positive relationship between dive time and ensuing pause time in 1996. Although it appears that aerobic diving was the norm, there appeared to be an increase in anaerobic diving in 1996. The diving performance of Marbled Murrelets in this study appeared to be affected by annual changes in environmental conditions and prey resources but did not consistently fit predictions from optimal-breathing models.

  8. 29 CFR Appendix B to Subpart T of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T.... 1910, Subpt. T, App. B Appendix B to Subpart T of Part 1910—Guidelines for Scientific Diving This... scientific diving programs which are exempt from the requirements for commercial diving. The guidelines...

  9. 29 CFR Appendix B to Subpart T of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T.... 1910, Subpt. T, App. B Appendix B to Subpart T of Part 1910—Guidelines for Scientific Diving This... scientific diving programs which are exempt from the requirements for commercial diving. The guidelines...

  10. CORE SATURATION BLOCKING OSCILLATOR

    DOEpatents

    Spinrad, R.J.

    1961-10-17

    A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

  11. Sympathetic Nerve Activity and Simulated Diving in Healthy Humans

    PubMed Central

    Shamsuzzaman, Abu; Ackerman, Michael J.; Kuniyoshi, Fatima Sert; Accurso, Valentina; Davison, Diane; Amin, Raouf S.; Somers, Virend K.

    2014-01-01

    The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea and congenital long QT syndrome. PMID:24368150

  12. Early diving behaviour in juvenile penguins: improvement or selection processes.

    PubMed

    Orgeret, Florian; Weimerskirch, Henri; Bost, Charles-André

    2016-08-01

    The early life stage of long-lived species is critical to the viability of population, but is poorly understood. Longitudinal studies are needed to test whether juveniles are less efficient foragers than adults as has been hypothesized. We measured changes in the diving behaviour of 17 one-year-old king penguins Aptenodytes patagonicus at Crozet Islands (subantartic archipelago) during their first months at sea, using miniaturized tags that transmitted diving activity in real time. We also equipped five non-breeder adults with the same tags for comparison. The data on foraging performance revealed two groups of juveniles. The first group made shallower and shorter dives that may be indicative of early mortality while the second group progressively increased their diving depths and durations, and survived the first months at sea. This surviving group of juveniles required the same recovery durations as adults, but typically performed shallower and shorter dives. There is thereby a relationship between improved diving behaviour and survival in young penguins. This long period of improving diving performance in the juvenile life stage is potentially a critical period for the survival of deep avian divers and may have implications for their ability to adapt to environmental change. PMID:27484650

  13. Characteristics of diving in radio-marked Xantus's Murrelets

    USGS Publications Warehouse

    Hamilton, C.D.; Golightly, R.T.; Takekawa, J.Y.

    2005-01-01

    We monitored diving activity of radio-marked Xantus's Murrelets Synthliboramphus hypoleucus near Anacapa Island, California, during the breeding season. Thirteen radio-marked murrelets were remotely monitored from Anacapa Island with a handheld antenna and radio receiver for 29 hours in three sample periods in April and May 2003. Mean dive durations in the sample periods were 18 s ?? 2 s, 28 s ?? 2 s, and 24 s ?? 4 s, suggesting that dives were less than 21 m from the surface. Dive duration and subsequent time on the surface differed between the sample periods. Dive duration and subsequent time on the surface were not correlated in observations stratified by individual bird or by sample period. Further, dive duration and subsequent time on the surface were not correlated within foraging bouts. Dive characteristics measured near Anacapa Island suggested that Xantus's Murrelets have the ability to capture prey found at varying depths, but will feed on prey that is most available near the surface of the water.

  14. Asthma and recreational SCUBA diving: a systematic review.

    PubMed

    Koehle, Michael; Lloyd-Smith, Rob; McKenzie, Don; Taunton, Jack

    2003-01-01

    Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity.There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making.

  15. Early diving behaviour in juvenile penguins: improvement or selection processes

    PubMed Central

    Weimerskirch, Henri; Bost, Charles-André

    2016-01-01

    The early life stage of long-lived species is critical to the viability of population, but is poorly understood. Longitudinal studies are needed to test whether juveniles are less efficient foragers than adults as has been hypothesized. We measured changes in the diving behaviour of 17 one-year-old king penguins Aptenodytes patagonicus at Crozet Islands (subantartic archipelago) during their first months at sea, using miniaturized tags that transmitted diving activity in real time. We also equipped five non-breeder adults with the same tags for comparison. The data on foraging performance revealed two groups of juveniles. The first group made shallower and shorter dives that may be indicative of early mortality while the second group progressively increased their diving depths and durations, and survived the first months at sea. This surviving group of juveniles required the same recovery durations as adults, but typically performed shallower and shorter dives. There is thereby a relationship between improved diving behaviour and survival in young penguins. This long period of improving diving performance in the juvenile life stage is potentially a critical period for the survival of deep avian divers and may have implications for their ability to adapt to environmental change. PMID:27484650

  16. Sympathetic nerve activity and simulated diving in healthy humans.

    PubMed

    Shamsuzzaman, Abu; Ackerman, Michael J; Kuniyoshi, Fatima Sert; Accurso, Valentina; Davison, Diane; Amin, Raouf S; Somers, Virend K

    2014-04-01

    The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age of 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea or congenital long QT syndrome.

  17. Optimal diving behaviour and respiratory gas exchange in birds.

    PubMed

    Halsey, Lewis G; Butler, Patrick J

    2006-11-01

    This review discusses the advancements in our understanding of the physiology and behaviour of avian diving that have been underpinned by optimal foraging theory and the testing of optimal models. To maximise their foraging efficiency during foraging periods, diving birds must balance numerous factors that are directly or indirectly related to the replenishment of the oxygen stores and the removal of excess carbon dioxide. These include (1) the time spent underwater (which diminishes the oxygen supply, increases carbon dioxide levels and may even include a build up of lactate due to anaerobic metabolism), (2) the time spent at the surface recovering from the previous dive and preparing for the next (including reloading their oxygen supply, decreasing their carbon dioxide levels and possibly also metabolising lactate) and (3) the trade-off between maximising oxygen reserves for consumption underwater by taking in more air to the respiratory system, and minimising the energy costs of positive buoyancy caused by this air, to maximise the time available underwater to forage. Due to its importance in avian diving, replenishment of the oxygen stores has become integral to models of optimal diving, which predict the time budgeting of animals foraging underwater. While many of these models have been examined qualitatively, such tests of predictive trends appear fallible and only quantifiable support affords strong evidence of their predictive value. This review describes how the quantification of certain optimal diving models, using tufted ducks, indeed demonstrates some predictive success. This suggests that replenishment of the oxygen stores and removal of excess carbon dioxide have significant influences on the duration of the surface period between dives. Nevertheless, present models are too simplistic to be robust predictors of diving behaviour for individual animals and it is proposed that they require refinement through the incorporation of other variables that also

  18. High feeding costs limit dive time in the largest whales.

    PubMed

    Acevedo-Gutiérrez, A; Croll, D A; Tershy, B R

    2002-06-01

    Large body size usually extends dive duration in air-breathing vertebrates. However, the two largest predators on earth, the blue whale (Balaenoptera musculus) and the fin whale (B. physalus), perform short dives for their size. Here, we test the hypothesis that the foraging behavior of these two species (lunge-feeding) is energetically expensive and limits their dive duration. We estimated the cost of lunge-feeding in both species using an approach that combined attaching time/depth recorders to seven blue whales and eight fin whales and comparing the collected dive information with predictions made by optimality models of dive behavior. We show that the rate at which whales recovered from a foraging dive was twice that of a non-foraging dive and that the cost of foraging relative to the cost of travel to and from the prey patch was 3.15 in blue whales (95 % CI 2.58-3.72) and 3.60 in fin whales (95 % CI 2.35-4.85). Whales foraged in small areas (<1 km(2)) and foraging bouts lasted more than one dive, indicating that prey did not disperse and thus that prey dispersal could not account for the limited dive durations of the whales. Despite the enormous size of blue whales and fin whales, the high energetic costs of lunge-feeding confine them to short durations of submergence and to areas with dense prey aggregations. As a corollary, because of their limited foraging time under water, these whales may be particularly vulnerable to perturbations in prey abundance.

  19. Open water scuba diving accidents at Leicester: five years' experience.

    PubMed Central

    Hart, A J; White, S A; Conboy, P J; Bodiwala, G; Quinton, D

    1999-01-01

    OBJECTIVES: The aim of this study was to determine the incidence, type, outcome, and possible risk factors of diving accidents in each year of a five year period presenting from one dive centre to a large teaching hospital accident and emergency (A&E) department. METHODS: All patients included in this study presented to the A&E department at a local teaching hospital in close proximity to the largest inland diving centre in the UK. Our main outcome measures were: presenting symptoms, administration of recompression treatment, mortality, and postmortem examination report where applicable. RESULTS: Overall, 25 patients experienced a serious open water diving accident at the centre between 1992 and 1996 inclusive. The percentage of survivors (n = 18) with symptoms of decompression sickness receiving recompression treatment was 52%. All surviving patients received medical treatment for at least 24 hours before discharge. The median depth of diving accidents was 24 metres (m) (range 7-36 m). During the study period, 1992-96, the number of accidents increased from one to 10 and the incidence of diving accidents increased from four per 100,000 to 15.4 per 100,000. Over the same time period the number of deaths increased threefold. CONCLUSIONS: The aetiology of the increase in the incidence of accidents is multifactorial. Important risk factors were thought to be: rapid ascent (in 48% of patients), cold water, poor visibility, the number of dives per diver, and the experience of the diver. It is concluded that there needs to be an increased awareness of the management of diving injuries in an A&E department in close proximity to an inland diving centre. PMID:10353047

  20. Effect of simulated dives on diastolic function in healthy men.

    PubMed

    Hansel, Jochen; Tetzlaff, Kay; Axmann, Detlef; Niess, Andreas M; Burgstahler, Christof

    2012-01-01

    Scuba diving may elicit acute changes to human cardiovascular function. Environmental stresses such as immersion, cold, and venous gas microbubbles all have been shown to contribute to right ventricular overload and impaired left ventricular filling after single dives. We investigated cardiac function after simulated dry chamber dives. Twenty male divers [mean age 31 years, standard deviation (SD) 8 years, mean body mass index 26 kgm(-2) (SD 3 kgm(-2))] participated in the study. All subjects had normal ECG, stress-ECG, and transthoracic echocardiography at rest. Echocardiographic assessment of diastolic function [E/A-ratio, deceleration time (DT), isovolumic relaxation time (IVRT), E/e'-ratio] was performed directly prior to and 20 and 80 min after two simulated dry hyperbaric chamber dives (maximal pressure 600 kPa, duration 60 min) that were conducted within 1 week. DT statistically significantly decreased from 163 ms (SD 14 ms) to 125 ms (SD 15 ms) 20 min after the dive (p < 0.0001), whereas 80 min after decompression these changes tended to return to baseline [146 ms (SD 14 ms); p = 0.06]. There was no statistically significant change in heart rate, E/A-ratio or E/e'-ratio after 20 or 80 min compared to baseline. These changes could be reproduced after the second dry chamber dive. No gas microbubbles were detectable during or after decompression from either dive. Simulated hyperbaric dry chamber dives were associated with a transient decrease in deceleration time in healthy men. Factors other than immersion, cold, or nitrogen microbubbles may contribute to acute changes in cardiac function after single scuba dives.

  1. [Diagnosis and treatment of diving accidents. New German guidelines for diving accidents 2014-2017].

    PubMed

    Jüttner, B; Wölfel, C; Liedtke, H; Meyne, K; Werr, H; Bräuer, T; Kemmerer, M; Schmeißer, G; Piepho, T; Müller, O; Schöppenthau, H

    2015-06-01

    In 2015 the German Society for Diving and Hyperbaric Medicine (GTÜM) and the Swiss Underwater and Hyperbaric Medical Society (SUHMS) published the updated guidelines on diving accidents 2014-2017. These multidisciplinary guidelines were developed within a structured consensus process by members of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI), the Sports Divers Association (VDST), the Naval Medical Institute (SchiffMedInst), the Social Accident Insurance Institution for the Building Trade (BG BAU), the Association of Hyperbaric Treatment Centers (VDD) and the Society of Occupational and Environmental Medicine (DGAUM). This consensus-based guidelines project (development grade S2k) with a representative group of developers was conducted by the Association of Scientific Medical Societies in Germany. It provides information and instructions according to up to date evidence to all divers and other lay persons for first aid recommendations to physician first responders and emergency physicians as well as paramedics and all physicians at therapeutic hyperbaric chambers for the diagnostics and treatment of diving accidents. To assist in implementing the guideline recommendations, this article summarizes the rationale, purpose and the following key action statements: on-site 100% oxygen first aid treatment, still patient positioning and fluid administration are recommended. Hyperbaric oxygen (HBO) recompression remains unchanged the established treatment in severe cases with no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa. For quality management purposes there is a need in the future for a nationwide register of hyperbaric therapy. PMID:26025255

  2. [Diagnosis and treatment of diving accidents. New German guidelines for diving accidents 2014-2017].

    PubMed

    Jüttner, B; Wölfel, C; Liedtke, H; Meyne, K; Werr, H; Bräuer, T; Kemmerer, M; Schmeißer, G; Piepho, T; Müller, O; Schöppenthau, H

    2015-06-01

    In 2015 the German Society for Diving and Hyperbaric Medicine (GTÜM) and the Swiss Underwater and Hyperbaric Medical Society (SUHMS) published the updated guidelines on diving accidents 2014-2017. These multidisciplinary guidelines were developed within a structured consensus process by members of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI), the Sports Divers Association (VDST), the Naval Medical Institute (SchiffMedInst), the Social Accident Insurance Institution for the Building Trade (BG BAU), the Association of Hyperbaric Treatment Centers (VDD) and the Society of Occupational and Environmental Medicine (DGAUM). This consensus-based guidelines project (development grade S2k) with a representative group of developers was conducted by the Association of Scientific Medical Societies in Germany. It provides information and instructions according to up to date evidence to all divers and other lay persons for first aid recommendations to physician first responders and emergency physicians as well as paramedics and all physicians at therapeutic hyperbaric chambers for the diagnostics and treatment of diving accidents. To assist in implementing the guideline recommendations, this article summarizes the rationale, purpose and the following key action statements: on-site 100% oxygen first aid treatment, still patient positioning and fluid administration are recommended. Hyperbaric oxygen (HBO) recompression remains unchanged the established treatment in severe cases with no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa. For quality management purposes there is a need in the future for a nationwide register of hyperbaric therapy.

  3. Alveolar hemorrhage after scuba diving: a case report.

    PubMed

    Tsai, Ming-Ju; Tsai, Mee-Sun; Tsai, Ying-Ming; Lien, Chi-Tun; Hwang, Jhi-Jhu; Huang, Ming-Shyan

    2010-07-01

    Self-contained underwater breathing apparatus (scuba) diving is increasingly popular in Taiwan. There are few references in the literature regarding pulmonary hemorrhage as the sole manifestation of pulmonary barotrauma in scuba divers, and no study from Taiwan was found in the literature. We present the case of a 25-year-old man who suffered alveolar hemorrhage related to pulmonary barotrauma as a complication of scuba diving. To our knowledge, this is the first case report describing a Taiwanese subject suffering from non-fatal pulmonary hemorrhage after scuba diving.

  4. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving.

  5. Energy cost and optimisation in breath-hold diving.

    PubMed

    Trassinelli, M

    2016-05-01

    We present a new model for calculating locomotion costs in breath-hold divers. Starting from basic mechanics principles, we calculate the work that the diver must provide through propulsion to counterbalance the action of drag, the buoyant force and weight during immersion. Compared to those in previous studies, the model presented here accurately analyses breath-hold divers which alternate active swimming with prolonged glides during the dive (as is the case in mammals). The energy cost of the dive is strongly dependent on these prolonged gliding phases. Here we investigate the length and impacts on energy cost of these glides with respect to the diver characteristics, and compare them with those observed in different breath-hold diving species. Taking into account the basal metabolic rate and chemical energy to propulsion transformation efficiency, we calculate optimal swim velocity and the corresponding total energy cost (including metabolic rate) and compare them with observations. Energy cost is minimised when the diver passes through neutral buoyancy conditions during the dive. This generally implies the presence of prolonged gliding phases in both ascent and descent, where the buoyancy (varying with depth) is best used against the drag, reducing energy cost. This is in agreement with past results (Miller et al., 2012; Sato et al., 2013) where, when the buoyant force is considered constant during the dive, the energy cost was minimised for neutral buoyancy. In particular, our model confirms the good physical adaption of dolphins for diving, compared to other breath-hold diving species which are mostly positively buoyant (penguins for example). The presence of prolonged glides implies a non-trivial dependency of optimal speed on maximal depth of the dive. This extends previous findings (Sato et al., 2010; Watanabe et al., 2011) which found no dependency of optimal speed on dive depth for particular conditions. The energy cost of the dive can be further

  6. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving. PMID:25369697

  7. A review of the forensic investigation of scuba diving deaths.

    PubMed

    Busuttil, A; Obafunwa, J

    1995-01-01

    With more people engaging in recreational scuba diving, fatalities from this sport are encountered by forensic investigators. There is a plethora of factors contributing to death and the investigator must be acquainted with how to elucidate them. The emphasis is on a multi-disciplinary approach that involves co-divers and instructors, the rescue team, the police, forensic scientists, diving equipment suppliers, underwater physiologists and physicians, decompression chamber personnel, general practitioners, relatives and the forensic pathologist. This report presents the various factors contributing to scuba diving deaths and suggests how to conduct such investigations.

  8. Inner ear decompression sickness following a shallow scuba dive.

    PubMed

    Reissman, P; Shupak, A; Nachum, Z; Melamed, Y

    1990-06-01

    Inner Ear Decompression Sickness (IEDCS)--manifested by tinnitus, vertigo, nausea, vomiting, and hearing loss--is usually associated with deep air or mixed gas dives, and accompanied by other CNS symptoms of decompression sickness (DCS). Early recompression treatment is required in order to avoid permanent inner ear damage. We present an unusual case of a scuba diver suffering from IEDCS as the only manifestation of DCS following a short shallow scuba dive, successfully treated by U.S. Navy treatment table 6 and tranquilizers. This case suggests that diving medical personnel should be more aware of the possible occurrence of IEDCS among the wide population of sport scuba divers.

  9. [Intraocular pressure in snorkling and diving (author's transl)].

    PubMed

    Kalthoff, H; John, S

    1976-02-01

    The reactions of the intraocular pressure (i.o.p) in snorkling and scuba diving were studies on 29 healthy subjects. A patient with chronic glaucoma simplex was examined in a pressure tank. The results confirm the author's opinion, that a well compensated chronic glaucoma simplex with intact discs and fields does not exclude fitness to dive. However, a diver with narrow angel glaucoma risks sudden rise in i.o.p. and acute glaucoma while ascending to the surface. Persons, who are examined for fitness to dive, should be seen by an ophthalmologist, if they have a glaucoma or if they are hypermetropic and over 40 years of age.

  10. Otolaryngology and sport scuba diving. Update and guidelines.

    PubMed

    Neblett, L M

    1985-01-01

    There are over a million certified sport scuba divers in the United States today. The sport is growing at an average annual rate of 7%. The vast majority of medical problems associated with scuba diving are related to the head and neck area, especially the ears. This paper provides an update on the physiology and pathophysiology of sport scuba diving. It also offers guidelines for the physician who may be called upon to examine candidates for the sport or to make decisions on continued diving for trained sport divers.

  11. Reduced taxonomic richness of lice (Insecta: Phthiraptera) in diving birds.

    PubMed

    Felsõ, B; Rózsa, L

    2006-08-01

    Avian lice occupy different habitats in the host plumage that the physical environment outside the host body may affect in several ways. Interactions between host plumage and water may be an important source of such effects. Here, we use a comparative approach to examine the effect of a host's diving behavior on the taxonomic richness of its lice. Louse genera richness was significantly lower in clades of diving birds than on their nondiving sister clades. Species richness of host and body mass did not differ significantly between these clades; thus, these factors did not bias our results. This study suggests that the hosts' diving behavior can effectively influence ectoparasite communities.

  12. Swedish recommendations on recreational diving and diabetes mellitus.

    PubMed

    Jendle, Johan; Adolfsson, Peter; Ornhagen, Hans

    2012-12-01

    Divers from many countries travel to explore various diving sites worldwide. In 2005, the Divers Alert Network (DAN) wrote guidelines for recreational diving and diabetes mellitus, but there is no up-to-date consensus or adoption of international guidelines on diabetes and diving. There are also large differences between the regulations in different countries. This is potentially both a medical and an insurance problem for a diver with diabetes. We present the current Swedish recommendations for recreational divers with Type 1 diabetes mellitus.

  13. Energy cost and optimisation in breath-hold diving.

    PubMed

    Trassinelli, M

    2016-05-01

    We present a new model for calculating locomotion costs in breath-hold divers. Starting from basic mechanics principles, we calculate the work that the diver must provide through propulsion to counterbalance the action of drag, the buoyant force and weight during immersion. Compared to those in previous studies, the model presented here accurately analyses breath-hold divers which alternate active swimming with prolonged glides during the dive (as is the case in mammals). The energy cost of the dive is strongly dependent on these prolonged gliding phases. Here we investigate the length and impacts on energy cost of these glides with respect to the diver characteristics, and compare them with those observed in different breath-hold diving species. Taking into account the basal metabolic rate and chemical energy to propulsion transformation efficiency, we calculate optimal swim velocity and the corresponding total energy cost (including metabolic rate) and compare them with observations. Energy cost is minimised when the diver passes through neutral buoyancy conditions during the dive. This generally implies the presence of prolonged gliding phases in both ascent and descent, where the buoyancy (varying with depth) is best used against the drag, reducing energy cost. This is in agreement with past results (Miller et al., 2012; Sato et al., 2013) where, when the buoyant force is considered constant during the dive, the energy cost was minimised for neutral buoyancy. In particular, our model confirms the good physical adaption of dolphins for diving, compared to other breath-hold diving species which are mostly positively buoyant (penguins for example). The presence of prolonged glides implies a non-trivial dependency of optimal speed on maximal depth of the dive. This extends previous findings (Sato et al., 2010; Watanabe et al., 2011) which found no dependency of optimal speed on dive depth for particular conditions. The energy cost of the dive can be further

  14. Representative learning design in springboard diving: Is dry-land training representative of a pool dive?

    PubMed

    Barris, Sian; Davids, Keith; Farrow, Damian

    2013-01-01

    Two distinctly separate training facilities (dry-land and aquatic) are routinely used in springboard diving and pose an interesting problem for learning, given the inherent differences in landing (head first vs. feet first) imposed by the different task constraints. Although divers may practise the same preparation phase, take-off and initial aerial rotation in both environments, there is no evidence to suggest that the tasks completed in the dry-land training environment are representative of those performed in the aquatic competition environment. The aim of this study was to compare the kinematics of the preparation phase of reverse dives routinely practised in each environment. Despite their high skill level, it was predicted that individual analyses of elite springboard divers would reveal differences in the joint coordination and board-work between take-offs. The two-dimensional kinematic characteristics were recorded during normal training sessions and used for intra-individual analysis. Kinematic characteristics of the preparatory take-off phase revealed differences in board-work (step lengths, jump height, board depression angles) for all participants at key events. However, the presence of scaled global topological characteristics suggested that all participants adopted similar joint coordination patterns in both environments. These findings suggest that the task constraints of wet and dry training environments are not similar, and highlight the need for coaches to consider representative learning designs in high performance diving programmes.

  15. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus)

    PubMed Central

    Rodgers, Essie M.; Schwartz, Jonathon J.; Franklin, Craig E.

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of ‘fright-dive’ capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; ‘moderate’ climate warming, 31.5°C; ‘high’ climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28–35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained ‘fright-dive’ performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  16. Orbital subperiosteal hematoma from scuba diving.

    PubMed

    Rosenberry, Clark; Angelidis, Matthew; Devita, Diane

    2010-09-01

    Only a few cases of nontraumatic orbital subperiosteal hematoma due to scuba diving have been reported, and this is the first of such cases that underwent surgical intervention. This injury results from negative pressure within the face mask, suctioning orbital tissues into the mask after incomplete equilibration of pressure on descent. Valsalva maneuver is a second mechanism implicated in the etiology of this injury. Recognition of this injury is of the utmost importance because vision loss is a possible complication if there is compression of the optic nerve or increased intraocular pressure. In many cases of nontraumatic orbital hematoma, conservative management is adequate; however, this case was an exception due to worsening exam findings. Divers may be able to prevent this injury by frequent and gentle equilibration of mask pressure on descent.

  17. [The pulmonary manifestations of diving accidents].

    PubMed

    Héritier, F; Schaller, M D; Fitting, J W; Feihl, F; Leuenberger, P; Perret, C

    1993-09-01

    Scuba diving is associated with risks of drowning, lung barotrauma and decompression sickness. In case of near-drowning, irreversible neurologic lesions or death may follow an acute hypoxemia or a cardiopulmonary arrest. Therefore, victims of drowning should benefit from an immediate and prolonged cardiopulmonary resuscitation. Lung barotrauma are due to the failure of expanding lung gases to escape during ascent; they are likely to be complicated by arterial gas embolism. They can follow a panic ascent even from a shallow depth. Most of decompression procedures induce the formation of asymptomatic venous gas bubbles, normally filtrated and eliminated by the lungs. In case of massive intravenous bubbling, the filtering capacity of the lungs can be overwhelmed and the lung microcirculation damaged up to the point of provoking a cardio-respiratory failure.

  18. Gluon saturation in a saturated environment

    SciTech Connect

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan

    2011-07-15

    A bootstrap equation for self-quenched gluon shadowing leads to a reduced magnitude of broadening for partons propagating through a nucleus. Saturation of small-x gluons in a nucleus, which has the form of transverse momentum broadening of projectile gluons in pA collisions in the nuclear rest frame, leads to a modification of the parton distribution functions in the beam compared with pp collisions. In nucleus-nucleus collisions all participating nucleons acquire enhanced gluon density at small x, which boosts further the saturation scale. Solution of the reciprocity equations for central collisions of two heavy nuclei demonstrate a significant, up to several times, enhancement of Q{sub sA}{sup 2}, in AA compared with pA collisions.

  19. Differential effects on nitric oxide synthase, heat shock proteins and glutathione in human endothelial cells exposed to heat stress and simulated diving.

    PubMed

    Fismen, Lise; Hjelde, Astrid; Svardal, Asbjørn M; Djurhuus, Rune

    2012-07-01

    Decompression sickness (DCS) may result from damage to the endothelium caused by the gas bubbles formed during decompression and may be related to nitric oxide (NO) production by nitric oxide synthase (NOS). Heat stress prior to diving has been shown to protect animals from DCS, and by simulating this treatment in human endothelial cells (HUVEC) we have shown that a simulated dive performed subsequent to a heat stress potentiated the heat-induced expression of HSP70 and increased the level of the antioxidant glutathione (GSH). Since operational saturation diving is performed at an increased oxygen level, HUVEC have been exposed to heat stress and simulated diving at 40 kPa O(2), comparing the response on HSP70, HSP90 and GSH level to the effects previously observed at 20 kPa O(2). In addition, we wanted to investigate the effect on both endothelial NOS (eNOS) protein and enzymatic activity. The present results showed that a heat stress (45°C, 1 h) decreased the NOS activity and the protein markedly. Hyperoxia (40 kPa) alone or a dive either at 20 or 40 kPa O(2),had no effects on NOS activity or protein. At 40 kPa O(2) a simulated dive after heat stress potentiated the HS-induced HSP70 response, whereas the heat-induced HSP90 response decreased. GSH levels were found to be inversely related to NOS activity and protein expression, and might be explained by a possible post-translational regulation by glutathionylation of eNOS protein. The results add to the limited knowledge of these critical factors in cellular defence mechanisms that can prevent injury during decompression.

  20. Effects of successive air and nitrox dives on human vascular function.

    PubMed

    Marinovic, Jasna; Ljubkovic, Marko; Breskovic, Toni; Gunjaca, Grgo; Obad, Ante; Modun, Darko; Bilopavlovic, Nada; Tsikas, Dimitrios; Dujic, Zeljko

    2012-06-01

    SCUBA diving is regularly associated with asymptomatic changes in cardiac, pulmonary and vascular function. The aim of this study was to evaluate the changes in vascular/endothelial function following SCUBA diving and to assess the potential difference between two breathing gases: air and nitrox 36 (36% oxygen and 64% nitrogen). Ten divers performed two 3-day diving series (no-decompression dive to 18 m with 47 min bottom time with air and nitrox, respectively), with 2 weeks pause in between. Arterial/endothelial function was assessed using SphygmoCor and flow-mediated dilation measurements, and concentration of nitrite before and after diving was determined in venous blood. Production of nitrogen bubbles post-dive was assessed by ultrasonic determination of venous gas bubble grade. Significantly higher bubbling was found after all air dives as compared to nitrox dives. Pulse wave velocity increased slightly (~6%), significantly after both air and nitrox diving, indicating an increase in arterial stiffness. However, augmentation index became significantly more negative after diving indicating smaller wave reflection. There was a trend for post-dive reduction of FMD after air dives; however, only nitrox diving significantly reduced FMD. No significant differences in blood nitrite before and after the dives were found. We found that nitrox diving affects systemic/vascular function more profoundly than air diving by reducing FMD response, most likely due to higher oxygen load. Both air and nitrox dives increased arterial stiffness, but decreased wave reflection suggesting a decrease in peripheral resistance due to exercise during diving. These effects of nitrox and air diving were not followed by changes in plasma nitrite.

  1. SCUBA Diving for Blind and Visually Impaired People.

    ERIC Educational Resources Information Center

    Candela, Anthony R.

    1982-01-01

    The author, a trained scuba (self-contained underwater breathing apparatus) diver who is severely visually impaired provides an orientation to scuba diving as a leisure and career activity. (Author/SB)

  2. The risks of scuba diving: a focus on Decompression Illness.

    PubMed

    Hall, Jennifer

    2014-11-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or "off-gassed," resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport.

  3. The source of circulating catecholamines in forced dived ducks.

    PubMed

    Lacombe, A M; Jones, D R

    1990-10-01

    Plasma catecholamines have been measured in chronically adrenalectomized (ADX) ducks, in chronically adrenal-denervated ducks (DNX), and in their respective shamoperated controls (SH-adx, SH-dnx) after 3 min forced submergence. The results showed that 100% of the plasma epinephrine (EP) and 70 to 80% of plasma norepinephrine (NE) released during the dive came from the adrenal glands. Only 20 to 30% of plasma NE came from the endings of the autonomic vascular sympathetic nerves which are strongly stimulated during diving. Adrenal catecholamines were released by nerve activation only; nonneural mechanisms did not play any role in their release. The action of adrenal catecholamines on the cardiovascular system during dives was investigated by measuring heart rate and arterial blood pressure in operated and sham-operated ducks. Cardiovascular adjustments, associated with 3 min of forced diving, were not affected by any differences in the levels of plasma catecholamines. PMID:2272478

  4. Differential air sac pressures in diving tufted ducks Aythya fuligula.

    PubMed

    Boggs, D F; Butler, P J; Wallace, S E

    1998-09-01

    The air in the respiratory system of diving birds contains a large proportion of the body oxygen stores, but it must be in the lungs for gas exchange with blood to occur. To test the hypothesis that locomotion induces mixing of air sac air with lung air during dives, we measured differential pressures between the interclavicular and posterior thoracic air sacs in five diving tufted ducks Aythya fuligula. The peak differential pressure between posterior thoracic and interclavicular air sacs, 0.49+/-0.13 kPa (mean +/- s.d.), varied substantially during underwater paddling as indicated by gastrocnemius muscle activity. These data support the hypothesis that locomotion, perhaps through associated abdominal muscle activity, intermittently compresses the posterior air sacs more than the anterior ones. The result is differential pressure fluctuations that might induce the movement of air between air sacs and through the lungs during dives. PMID:9716518

  5. The risks of scuba diving: a focus on Decompression Illness.

    PubMed

    Hall, Jennifer

    2014-11-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or "off-gassed," resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  6. The Risks of Scuba Diving: A Focus on Decompression Illness

    PubMed Central

    2014-01-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or “off-gassed,” resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  7. Health risk management in the Tasmanian abalone diving industry.

    PubMed

    Smart, David

    2010-06-01

    Risk management is a systematic process applied to all aspects of diving operations. The process aims to reduce accidents and adverse outcomes to a minimum. Risk results from a combination of probability and consequence, and where this combination has major or extreme impact, the risk should not be tolerated. Over the four years 2001-2004, the incidence of decompression illness amongst abalone divers in Tasmania was 1.4 cases per 100 divers per year. Risk management in diving encompasses medical fitness, education and training, dive planning, equipment and maintenance, emergency procedures and equipment, and continual vigilance to remedy new risks as they are identified. There is still much to achieve in the Tasmanian abalone diving industry in all areas of risk management.

  8. The development of hyperbaric and diving medicine in Singapore.

    PubMed

    Chng, J; Low, C T; Kang, W L

    2011-12-01

    Hyperbaric oxygen therapy is a noninvasive therapy used in the treatment of diving-related medical illnesses. It is an important adjunct in the management of a variety of medical conditions. The Republic of Singapore Navy Medical Service (NMS) is the main driver of the development of hyperbaric and diving medicine in Singapore. The practice of hyperbaric medicine has inherent risks, and unregulated application of this therapy may do more harm than good. NMS and Singapore General Hospital (SGH) signed a Memorandum of Understanding to combine NMS' experience with the clinical expertise of SGH to provide holistic care for diving and clinical hyperbaric treatment patients. This collaboration would increase the profile of this clinical specialty in Singapore, and help to establish safe clinical practice guidelines, training and accreditation requirements for diving and hyperbaric medicine practitioners in Singapore, thus ensuring that the practice of bona fide hyperbaric medicine is safeguarded and patient care is not compromised.

  9. First records of dive durations for a hibernating sea turtle

    PubMed Central

    Hochscheid, Sandra; Bentivegna, Flegra; Hays, Graeme C

    2005-01-01

    The first published record, from the early 1970s, of hibernation in sea turtles is based on the reports of the indigenous Indians and fishermen from Mexico, who hunted dormant green turtles (Chelonia mydas) in the Gulf of California. However, there were no successful attempts to investigate the biology of this particular behaviour further. Hence, data such as the exact duration and energetic requirements of dormant winter submergences are lacking. We used new satellite relay data loggers to obtain the first records of up to 7 h long dives of a loggerhead turtle (Caretta caretta) overwintering in Greek waters. These represent the longest dives ever reported for a diving marine vertebrate. There is strong evidence that the dives were aerobic, because the turtle surfaced only for short intervals and before the calculated oxygen stores were depleted. This evidence suggests that the common belief that sea turtles hibernate underwater, as some freshwater turtles do, is incorrect. PMID:17148134

  10. South African underwater diving accidents, 1969-1976.

    PubMed

    Landsberg, P G

    1976-12-25

    Since 1969 a survey of diving accidents involving South African amateur divers was undertaken. The South African Underwater Union diving accident report form was used, and various State agents (SA Police and inquest courts) and individual divers and club instructors were questioned. This survey covers the period up to the end of June 1976. Data acquired during the 8-year period 1969 - 1976 are compared. A conservative estimate from the number of certificates issued to club divers indicates a 25% increase in diver population, while the number of fatilities has decreased from 0,1% in 1971 to 0,016% in 1976, indicating the importance of accident reporting in determining safety trends. In general, a change in pattern is observed during the last 4 years, showing more SCUBA than breath-hold fatalities. The formation of the Decompression Sickness and Diving Accidents Investigation Panel as a further measure to decrease fatal diving accidents is discussed.

  11. 23. VIEW, FROM EAST, SHOWING DIVING AND MAIN POOLS AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. VIEW, FROM EAST, SHOWING DIVING AND MAIN POOLS AND WEST ELEVATION OF OFFICE AND FIRST AID BUILDING - Glen Echo Park, Crystal Swimming Pool, 7300 McArthur Boulevard, Glen Echo, Montgomery County, MD

  12. [Retinal vein occlusion and deep-sea diving].

    PubMed

    Merle, H; Drault, J N; Gerard, M; Alliot, E; Mehdaoui, H; Elisabeth, L

    1997-01-01

    We report a case of retinal vein occlusion after breath-holding diving. After one hour of diving at a maximal depth of eight meters, each apnea no longer than one minute, the patient complained of a diminution of the visual acuity in the left eye. Ophthalmological examination revealed an occlusion of the superior branch of the central vein of the retina in the left eye. This could be considered as a decompression sickness even if the occlusion could happen fortuitously in water. Secondary to the multiple descents, a bubble would have appeared in the vein leading to an obstruction. The purpose of this paper is to discuss a possible link between the breath-holding diving and this kind of accident. We also report the different ophthalmological features that may occur while diving.

  13. Comparison of sequential and 7-, 10-, 14-d triple therapy for Helicobacter pylori infection

    PubMed Central

    Choi, Hyuk Soon; Chun, Hoon Jai; Park, Sang Hoon; Keum, Bora; Seo, Yeon Seok; Kim, Yong Sik; Jeen, Yoon-Tae; Um, Soon Ho; Lee, Hong Sik; Kim, Chang Duck; Ryu, Ho Sang

    2012-01-01

    AIM: To compare the effectiveness of sequential therapy for Helicobacter pylori (H. pylori) infection with that of triple therapy of varying durations. METHODS: The 460 patients enrolled in this study had H. pylori-associated gastritis or a gastric or duodenal ulcer. After screening, H. pylori-infected patients were randomly assigned to receive either conventional triple therapy for 7, 10 or 14 d, or a new 10-d sequential therapy. Each of the 4 treatment groups included 115 patients. The outcomes of eradication therapy were assessed 4 wk after treatment by the urea breath test and histology. RESULTS: The overall eradication rate was 81.0%, and eradication rates were 75.7% for 7-d conventional triple therapy, 81.9% for 10-d conventional triple therapy, 84.4% for 14-d conventional triple therapy, and 82.0% for 10-d sequential therapy. Neither intention-to-treat analysis nor per protocol analysis showed significant differences in eradication rates using sequential therapy or the standard triple therapy (P = 0.416 and P = 0.405, respectively). CONCLUSION: There are no significant differences between 10-d sequential eradication therapy for H. pylori and any duration of standard triple treatment in Korean patients. PMID:22654429

  14. Diving decompression models and bubble metrics: modern computer syntheses.

    PubMed

    Wienke, B R

    2009-04-01

    A quantitative summary of computer models in diving applications is presented, underscoring dual phase dynamics and quantifying metrics in tissue and blood. Algorithms covered include the multitissue, diffusion, split phase gradient, linear-exponential, asymmetric tissue, thermodynamic, varying permeability, reduced gradient bubble, tissue bubble diffusion, and linear-exponential phase models. Defining relationships are listed, and diver staging regimens are underscored. Implementations, diving sectors, and correlations are indicated for models with a history of widespread acceptance, utilization, and safe application across recreational, scientific, military, research, and technical communities. Presently, all models are incomplete, but many (included above) are useful, having resulted in diving tables, underwater meters, and dive planning software. Those herein employ varying degrees of calibration and data tuning. We discuss bubble metrics in tissue and blood as a backdrop against computer models. The past 15 years, or so, have witnessed changes and additions to diving protocols and table procedures, such as shorter nonstop time limits, slower ascent rates, shallow safety stops, ascending repetitive profiles, deep decompression stops, helium based breathing mixtures, permissible reverse profiles, multilevel techniques, both faster and slower controlling repetitive tissue halftimes, smaller critical tensions, longer flying-after-diving surface intervals, and others. Stimulated by Doppler and imaging technology, table and decompression meter development, theory, statistics, chamber and animal testing, or safer diving consensus, these modifications affect a gamut of activity, spanning bounce to decompression, single to multiday, and air to mixed gas diving. As it turns out, there is growing support for many protocols on operational, experimental, and theoretical grounds, with bubble models addressing many concerns on plausible bases, but with further testing or

  15. Diving decompression models and bubble metrics: modern computer syntheses.

    PubMed

    Wienke, B R

    2009-04-01

    A quantitative summary of computer models in diving applications is presented, underscoring dual phase dynamics and quantifying metrics in tissue and blood. Algorithms covered include the multitissue, diffusion, split phase gradient, linear-exponential, asymmetric tissue, thermodynamic, varying permeability, reduced gradient bubble, tissue bubble diffusion, and linear-exponential phase models. Defining relationships are listed, and diver staging regimens are underscored. Implementations, diving sectors, and correlations are indicated for models with a history of widespread acceptance, utilization, and safe application across recreational, scientific, military, research, and technical communities. Presently, all models are incomplete, but many (included above) are useful, having resulted in diving tables, underwater meters, and dive planning software. Those herein employ varying degrees of calibration and data tuning. We discuss bubble metrics in tissue and blood as a backdrop against computer models. The past 15 years, or so, have witnessed changes and additions to diving protocols and table procedures, such as shorter nonstop time limits, slower ascent rates, shallow safety stops, ascending repetitive profiles, deep decompression stops, helium based breathing mixtures, permissible reverse profiles, multilevel techniques, both faster and slower controlling repetitive tissue halftimes, smaller critical tensions, longer flying-after-diving surface intervals, and others. Stimulated by Doppler and imaging technology, table and decompression meter development, theory, statistics, chamber and animal testing, or safer diving consensus, these modifications affect a gamut of activity, spanning bounce to decompression, single to multiday, and air to mixed gas diving. As it turns out, there is growing support for many protocols on operational, experimental, and theoretical grounds, with bubble models addressing many concerns on plausible bases, but with further testing or

  16. [Evaluation of diving stress implication of analysis of work loads].

    PubMed

    Mano, Y

    1987-05-01

    An investigation was conducted on the actual diving conditions of 2,996 divers in Japan except those engaged in fishery. Results of analysis made on the diving profiles and actual working conditions showed that some of their jobs required heavy load and that the burden was excessively large. Little study has been made for the proper evaluation of diving stress or work loads, but it has been assumed from these limited studies that the load is not so heavy. The load has been generally estimated to be about 1.8l/min STPD of oxygen consumption (VO2) during 40 l/min STPD of expiratory gas volume/min (VE). In our examination of their actual diving work, their work load was far greater than our expectation. It was in practice not only difficult to obtain the actual VO2 but also very difficult to determine their actual fatigue. Instead of these, it is necessary to establish an adequate index for evaluating diving work load. Studies have been made in our laboratory since 1981 and regression equations have been finally obtained, by which load during diving work can be determined using heart rate as index. Seven healthy males were chosen as subjects of the present study having a mean age of 34.4 yr and a mean diving history of 7.3 yr. First, performance time was acquired in each subject by bicycle ergometer exercise and the maximalen oxygen consumption (VO2-max) was obtained. In the second step, VO2-max was obtained by using the regulator apparatus for breathing during SCUBA diving. This value was 86.1% of the first step. The third step was made in a swimming pool.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Nitrogen narcosis and alcohol consumption--a scuba diving fatality.

    PubMed

    Michalodimitrakis, E; Patsalis, A

    1987-07-01

    Nitrogen narcosis can cause death among experienced scuba divers. Nitrogen under pressure affects the brain by acting as an anesthetic agent. Furthermore, the consumption of ethanol along with diving will cause the symptoms of nitrogen narcosis to occur at depths less than 30 m. Our case deals with an experienced diver who drank alcoholic beverages before diving and developed symptoms of nitrogen narcosis at a shallow depth. These two conditions contributed to his death by drowning.

  18. Neurological consequences of scuba diving with chronic sinusitis.

    PubMed

    Parell, G J; Becker, G D

    2000-08-01

    Sinus barotrauma from scuba diving is relatively common, usually self-limiting, and often the result of transient nasal pathology. We describe serious neurological sequelae occurring in two scuba divers who had chronic sinusitis We suggest guidelines for evaluating and treating divers who have chronic sinusitis. Divers with nasal or sinus pathology should be aware of the potentially serious consequences associated with scuba diving even after endoscopic sinus surgery to correct this condition.

  19. Heliox treatment for spinal decompression sickness following air dives.

    PubMed

    Douglas, J D; Robinson, C

    1988-07-01

    Enforced delay in treatment of spinal decompression sickness following scuba diving can result in paraplegia. Poor response from initial recompression to 18 m presents the clinician with a difficult management problem. Theoretical objections have been raised to the use of He-O2 as treatment regimen. We report 3 cases that show He-O2 to be an excellent method of treatment in spinal decompression sickness after air diving.

  20. Ocular barotrauma caused by mask squeeze during a scuba dive.

    PubMed

    Rudge, F W

    1994-07-01

    I describe the case of a 25-year-old man who, after a scuba dive, had ocular barotrauma caused by mask squeeze. As in most cases, the condition occurred because the patient failed to exhale into the mask during descent to equalize the pressure within the mask. Although alarming in appearance, the condition is generally mild and self-limited. Patients should be instructed in the proper technique of mask clearing before they return to diving to prevent a recurrence.

  1. Developing an effective diving program for a hydro maintenance project

    SciTech Connect

    Stasch, E.

    1997-08-01

    A trash problem at the Fort Randall hydropower project threatened to affect operations and cause potential machinery damage. When traditional approaches to clean away the trash were judged unfeasible, US Army Corps of Engineers managers developed a combined mechanical cleanup and underwater diving program. A contractor successfully removed 500 tons of debris at a cost of about $302,000. The dive plan and problems experienced during the project are detailed in the article.

  2. Activation of Brainstem Neurons by Underwater Diving in the Rat

    PubMed Central

    Panneton, W. Michael; Gan, Qi; Le, Jason; Livergood, Robert S.; Clerc, Philip; Juric, Rajko

    2012-01-01

    The mammalian diving response is a powerful autonomic adjustment to underwater submersion greatly affecting heart rate, arterial blood pressure, and ventilation. The bradycardia is mediated by the parasympathetic nervous system, arterial blood pressure is mediated via the sympathetic system and still other circuits mediate the respiratory changes. In the present study we investigate the cardiorespiratory responses and the brainstem neurons activated by voluntary diving of trained rats, and, compare them to control and swimming animals which did not dive. We show that the bradycardia and increase in arterial blood pressure induced by diving were significantly different than that induced by swimming. Neuronal activation was calculated after immunohistochemical processing of brainstem sections for Fos protein. Labeled neurons were counted in the caudal pressor area, the medullary dorsal horn, subnuclei of the nucleus tractus solitarii (NTS), the nucleus raphe pallidus (RPa), the rostroventrolateral medulla, the A5 area, the nucleus locus coeruleus, the Kölliker–Fuse area, and the external lateral and superior lateral subnuclei of the parabrachial nucleus. All these areas showed significant increases in Fos labeling when data from voluntary diving rats were compared to control rats and all but the commissural subnucleus of the NTS, A5 area, and RPa were significantly different from swimming rats. These data provide a substrate for more precise experiments to determine the role of these nuclei in the reflex circuits driving the diving response. PMID:22563319

  3. Acute ischemic colitis secondary to air embolism after diving.

    PubMed

    Payor, Austin Daniel; Tucci, Veronica

    2011-01-01

    Ischemic colitis (IC) secondary to air embolism from decompression sickness or barotrauma during diving is an extremely rare condition. After extensive review of the available literature, we found that there has been only one reported case of IC secondary to air embolism from diving. Although air embolization from diving and the various medical complications that follow have been well documented, the clinical manifestation of IC from an air embolism during diving is very rare and thus far unstudied. Common symptoms of IC include abdominal pain, bloody or non-bloody diarrhea or nausea or vomiting or any combination. Emergency physicians and Critical Care specialists should consider IC as a potential diagnosis for a patient with the above-mentioned symptoms and a history of recent diving. We report a case of IC from air embolism after a routine dive to 75 feet below sea level in a 53-year-old White female who presented to a community Emergency Department complaining of a 2-day history of diffuse abdominal pain and nausea. She was diagnosed by colonoscopy with biopsies and treated conservatively with antibiotics, bowel rest, and a slow advancement in diet.

  4. Pulmonary function in children after a single scuba dive.

    PubMed

    Lemaître, F; Tourny-Chollet, C; Hamidouche, V; Lemouton, M C

    2006-11-01

    This study evaluated the respiratory effects of a single dive in children. Eighteen young divers and 18 controls participated in our study (age range: 9 - 13 years). Volumes and expiratory flow rates were measured 20 minutes before and 10 minutes after one air dive (3 meters, 25 minutes). Before the dive, no differences were noted regarding pulmonary parameters. Ten minutes after the dive, decreases were noted in forced expiratory volume in 1 s (FEV1) and maximal voluntary ventilation (- 8 %, - 5.3 %, respectively; p < 0.01), peak expiratory flow, maximal expiratory flow rates at 50 % of FVC (MEF(50 %)) and MEF(25 %), forced mid-expiratory flow rate (FEF(25 - 75 %)), and FEV1/FVC(- 5.9 %, - 14.3 %, - 21.4 %, - 4.2 %, - 3.5 %, respectively; p < 0.05). The respiratory pattern observed 10 minutes after a single dive to three meters indicated airway narrowing. However, no association between diving experience and lung function was obtained.

  5. Risk factors for dive injury: a survey study.

    PubMed

    Beckett, Adam; Kordick, Mary Frances

    2007-01-01

    Scuba diving is a world sport, but it is not medically regulated. Study objectives sought to identify risk behaviors, preexisting medical conditions, compliance to dive guidelines, and injury patterns of recreational scuba divers. An Internet-based survey examined risk behaviors and diver safety practices. Responses from 682 of 770 (88.6%) divers revealed that 80.6% were certified; 51.7% of certified divers reported diving injuries versus 75.0% for noncertified divers (RR = 1.31; 95% CI: 1.16-1.48; P < 0.001); suspected decompression symptoms were witnessed by 52.6% of divers; 32.7% of certified divers reported medical problems including hypertension, asthma, diabetes, and epilepsy. No significant differences were observed in injuries among the certified divers based on dive frequency (P = 1.000), medical conditions (P = 0.750), smoking (P = 0.545), alcohol (P = 0.649), or illicit substances use (P = 0.230). Among certified divers, there was a positive association with fewer diving injuries but not with diving frequency, preexisting medical condition(s), smoking, alcohol, or illicit substance use.

  6. Expression of endothelial selectin ligands on human leukocytes following dive.

    PubMed

    Glavas, Duska; Markotic, Anita; Valic, Zoran; Kovacic, Natasa; Palada, Ivan; Martinic, Roko; Breskovic, Toni; Bakovic, Darija; Brubakk, Alf O; Dujic, Zeljko

    2008-09-01

    The fact that impaired endothelial-dependent vasodilatation after scuba diving often occurs without visible changes in the endothelial layer implies its biochemical origin. Since Lewisx(CD15) and sialyl-Lewisx(CD15s) are granulocyte and monocyte carbohydrate antigens recognized as ligands by endothelial selectins, we assumed that they could be sensitive markers for impaired vasodilatation following diving. Using flow cytometry, we determined the CD15 and CD15s peripheral blood mononuclear cells of eight divers, 30 mins before and 50 mins after a single dive to 54 m for 20 mins bottom time. The number of gas bubbles in the right heart was monitored by ultrasound. Gas bubbles were seen in all eight divers, with the average number of bubbles/cm2 1.9+/-1.9. The proportion of CD15+monocytes increased 2-fold after the dive as well as the subpopulation of monocytes highly expressing CD15s. The absolute number of monocytes was slightly, but not significantly, increased after the dive, whereas the absolute number of granulocytes was markedly elevated (up to 61%). There were no significant correlations between bubble formation and CD15+monocyte expression (r=-0.56; P=0.17), as well as with monocytes highly expressing CD15s (r=0.43; P=0.29). This study suggests that biochemical changes induced by scuba diving primarily activate existing monocytes rather than increase the number of monocytes at a time of acute arterial endothelial dysfunction.

  7. Antioxidants may Attenuate Plasma Erythropoietin Decline after Hyperbaric Oxygen Diving.

    PubMed

    Mutzbauer, T S; Schneider, M; Neubauer, B; Weiss, M; Tetzlaff, K

    2015-11-01

    According to previous studies, plasma erythropoietin (EPO) may decrease after hyperbaric oxygen exposure due to oxidative stress. It is hypothesized that the decrease of EPO can be attenuated by oxygen free radical scavengers.The aim of the present study was to evaluate whether EPO plasma levels can be influenced by oral application of vitamin C and E before repeated hyperbaric oxygen exposure during diving. 16 healthy male police task force divers performed 3 morning dives on oxygen within a regular diving schedule on 3 consecutive days. They were randomized into either the placebo group or the vitamin group, receiving 1 g ascorbic acid and 600 IU D-α-tocopherol orally 60 min before the dive. Blood samples for EPO measurement were taken on days 1, 2, and 3 at T1, T3 and T5 60 min before and at T2, T4 and T6 60 min after each dive, respectively. A moderate decrease of EPO was observed beginning at T3 until T6 in the placebo group. The EPO concentrations in the vitamin group did not show relevant variations compared to baseline. Radical scavenging vitamins C and D may counteract hyperbaric oxygen related mechanisms reducing EPO production in hyperbaric oxygen exposure during diving.

  8. Central nervous dysfunction associated with deep-sea diving.

    PubMed

    Aarli, J A; Vaernes, R; Brubakk, A O; Nyland, H; Skeidsvoll, H; Tønjum, S

    1985-01-01

    A group of 23 professional divers was investigated before and after dives to 300 and 350 metres of sea water. 12 divers were also studied during the actual dive. All divers presented neurological symptoms and signs during compression. Intention tremor, ataxia, motor weakness, sensory symptoms, vertigo, nausea and reduced memory were the most prominent features of the High Pressure Nervous Syndrome (HPNS). There were considerable individual differences. Neuropsychological and neurophysiological investigations performed after one dive showed no significant changes in any of the divers, while there was a clear-cut impairment in a group of 6 divers who had performed 2 dives 3 months apart. These changes indicate that there may be pressure-induced brain dysfunction which persists for a transient post-dive period. Loss of short-term memory is a prominent part of this dysfunction. Transitory neurological signs indicating focal cerebral dysfunction were found immediately post-dive in 4 divers, presumably reflecting the unmasking of pre-existing subclinical minimal CNS lesions.

  9. Atopy, airway reactivity and compressed air diving in males.

    PubMed

    Tetzlaff, K; Neubauer, B; Reuter, M; Friege, L

    1998-01-01

    A decline in expiratory flow rates in divers has recently been attributed to chronic exposure to hyberbaric air. Airway hyperresponsiveness (AHR) to stimuli due to a hyperbaric environment may play a certain role in this context. The aim of this study was to determine the prevalence of AHR in compressed air divers and to assess the value of bronchial challenges for prediction of fitness to dive. A cross-sectional sample of 59 healthy male volunteers--28 divers and 31 diving candidates (controls)--who had been found fit to dive in a diving medical examination underwent additional allergy screening (skin prick and serum IgE) and a histamine bronchial challenge. Pre- and postchallenge body plethysmography was completed to assess AHR. AHR to histamine was significantly increased among divers and positively related to diving experience whereas divers and controls did not differ significantly with respect to age, anthropometric data, current smoking habits, skin prick reaction, and elevated serum IgE. Our results indicate an increased prevalence of AHR to nonspecific inhalation stimuli in experienced divers. Bronchial challenge tests may be helpful to detect asthmatics in the medical assessment of fitness to dive and for follow-up examinations during a diver's career. PMID:9730792

  10. Poor flight performance in deep-diving cormorants.

    PubMed

    Watanabe, Yuuki Y; Takahashi, Akinori; Sato, Katsufumi; Viviant, Morgane; Bost, Charles-André

    2011-02-01

    Aerial flight and breath-hold diving present conflicting morphological and physiological demands, and hence diving seabirds capable of flight are expected to face evolutionary trade-offs regarding locomotory performances. We tested whether Kerguelen shags Phalacrocorax verrucosus, which are remarkable divers, have poor flight capability using newly developed tags that recorded their flight air speed (the first direct measurement for wild birds) with propeller sensors, flight duration, GPS position and depth during foraging trips. Flight air speed (mean 12.7 m s(-1)) was close to the speed that minimizes power requirement, rather than energy expenditure per distance, when existing aerodynamic models were applied. Flights were short (mean 92 s), with a mean summed duration of only 24 min day(-1). Shags sometimes stayed at the sea surface without diving between flights, even on the way back to the colony, and surface durations increased with the preceding flight durations; these observations suggest that shags rested after flights. Our results indicate that their flight performance is physiologically limited, presumably compromised by their great diving capability (max. depth 94 m, duration 306 s) through their morphological adaptations for diving, including large body mass (enabling a large oxygen store), small flight muscles (to allow for large leg muscles for underwater propulsion) and short wings (to decrease air volume in the feathers and hence buoyancy). The compromise between flight and diving, as well as the local bathymetry, shape the three-dimensional foraging range (<26 km horizontally, <94 m vertically) in this bottom-feeding cormorant. PMID:21228200

  11. Should children be SCUBA diving?: Cerebral arterial gas embolism in a swimming pool.

    PubMed

    Johnson, Valerie; Adkinson, Cheryl; Bowen, Mariya; Ortega, Henry

    2012-04-01

    Cerebral arterial gas embolism (CAGE) is a well-known serious complication of self-contained breathing apparatus (SCUBA) diving. Most serious complications of SCUBA diving occur in adults because most of SCUBA divers are adults. However, young age is an independent risk factor for injury in SCUBA diving and shallow-water SCUBA diving is the riskiest environment for CAGE. We present a case of a 10-year-old boy who developed CAGE while taking SCUBA diving lessons in a university swimming pool. This case illustrates the potential danger of SCUBA diving for children who lack understanding of the physics of diving as well as the often unappreciated risk of shallow-water SCUBA diving. Our intent is to educate providers of primary care to children, so that they may appropriately advise parents about SCUBA diving, and to educate providers of emergency care to children, so that they will recognize this uncommon but serious emergency condition.

  12. Breathing hypoxic gas affects the physiology as well as the diving behaviour of tufted ducks.

    PubMed

    Halsey, Lewis G; Butler, Patrick J; Woakes, Anthony J

    2005-01-01

    We measured the effects of exposure to hypoxia (15% and 11% oxygen) and hypercapnia (up to 4.5% carbon dioxide) on rates of respiratory gas exchange both between and during dives in tufted ducks, Aythya fuligula, to investigate to what extent these may explain changes in diving behaviour. As found in previous studies, the ducks decreased dive duration (t(d)) and increased surface duration when diving from a hypoxic or hypercapnic gas mix. In the hypercapnic conditions, oxygen consumption during the dive cycle was not affected. Oxygen uptake between dives was reduced by only 17% when breathing a hypoxic gas mix of 11% oxygen. However, estimates of the rate of oxygen metabolism during the foraging periods of dives decreased nearly threefold in 11% oxygen. Given that tufted ducks normally dive well within their aerobic dive limits and that they significantly reduced their t(d) during hypoxia, it is not at all clear why they make this physiological adjustment. PMID:15778946

  13. Scuba diving and fetal well-being: a survey of 208 women.

    PubMed

    Bolton, M E

    1980-09-01

    Scuba diving is an increasingly popular sport among women of childbearing age. It causes physiological changes that are possibly lethal or teratogenic to the fetus. The subject of diving during pregnancy is seldom mentioned in diving courses, however, and few obstetricians are familiar with the physiology of diving. The study employed mailed questionnaires for description and comparison of the extent of diving and obstetric and fetal outcome of 208 women divers, 136 of whom dived during one or more pregnancies. Depths to which these women dived averaged 42.6 ft; 24 women, however, reported dives deeper than 99 ft during the first trimester. I analyzed the prevalence of six specific fetal complications and found that the frequency of birth defects was significantly greater among children from pregnancies during which women dived (P < 0.05) but was within the range for the general population.

  14. Regional heterothermy and conservation of core temperature in emperor penguins diving under sea ice.

    PubMed

    Ponganis, P J; Van Dam, R P; Levenson, D H; Knower, T; Ponganis, K V; Marshall, G

    2003-07-01

    Temperatures were recorded at several body sites in emperor penguins (Aptenodytes forsteri) diving at an isolated dive hole in order to document temperature profiles during diving and to evaluate the role of hypothermia in this well-studied model of penguin diving physiology. Grand mean temperatures (+/-S.E.) in central body sites during dives were: stomach: 37.1+/-0.2 degrees C (n=101 dives in five birds), pectoral muscle: 37.8+/-0.1 degrees C (n=71 dives in three birds) and axillary/brachial veins: 37.9+/-0.1 degrees C (n=97 dives in three birds). Mean diving temperature and duration correlated negatively at only one site in one bird (femoral vein, r=-0.59, P<0.05; range <1 degrees C). In contrast, grand mean temperatures in the wing vein, foot vein and lumbar subcutaneous tissue during dives were 7.6+/-0.7 degrees C (n=157 dives in three birds), 20.2+/-1.2 degrees C (n=69 in three birds) and 35.2+/-0.2 degrees C (n=261 in six birds), respectively. Mean limb temperature during dives negatively correlated with diving duration in all six birds (r=-0.29 to -0.60, P<0.05). In two of six birds, mean diving subcutaneous temperature negatively correlated with diving duration (r=-0.49 and -0.78, P<0.05). Sub-feather temperatures decreased from 31 to 35 degrees C during rest periods to a grand mean of 15.0+/-0.7 degrees C during 68 dives of three birds; mean diving temperature and duration correlated negatively in one bird (r=-0.42, P<0.05). In general, pectoral, deep venous and even stomach temperatures during diving reflected previously measured vena caval temperatures of 37-39 degrees C more closely than the anterior abdominal temperatures (19-30 degrees C) recently recorded in diving emperors. Although prey ingestion can result in cooling in the stomach, these findings and the lack of negative correlations between internal temperatures and diving duration do not support a role for hypothermia-induced metabolic suppression of the abdominal organs as a mechanism of

  15. Development of AIM-7 flight clearance for the F-14D TECHEVAL

    SciTech Connect

    Sferlazza, M.A. )

    1992-02-01

    Recent advances in flow field analysis and synthesis techniques have greatly enhanced the capability to simulate store trajectories when released within the aerodynamic interference region of the parent aircraft. In the absence of wind tunnel data for specific aircraft/store combinations, the ability to effectively use existing wind tunnel data from other aircraft/store combinations can greatly enhance the ability to reduce cost and schedule associated with additional flow field wind tunnel testing required to support trajectory simulation analyses. An example of the excellent results obtainable utilizing these techniques has been demonstrated during the recently completed F-14 D TECHEVAL program. The paper describes the procedure used to support this program, shows how the Influence Function Method was used to eliminate the need for additional wind tunnel tests, and validates the approach for use in future weapon separation programs. 5 refs.

  16. Determinants of arterial gas embolism after scuba diving.

    PubMed

    Ljubkovic, Marko; Zanchi, Jaksa; Breskovic, Toni; Marinovic, Jasna; Lojpur, Mihajlo; Dujic, Zeljko

    2012-01-01

    Scuba diving is associated with breathing gas at increased pressure, which often leads to tissue gas supersaturation during ascent and the formation of venous gas emboli (VGE). VGE crossover to systemic arteries (arterialization), mostly through the patent foramen ovale, has been implicated in various diving-related pathologies. Since recent research has shown that arterializations frequently occur in the absence of cardiac septal defects, our aim was to investigate the mechanisms responsible for these events. Divers who tested negative for patent foramen ovale were subjected to laboratory testing where agitated saline contrast bubbles were injected in the cubital vein at rest and exercise. The individual propensity for transpulmonary bubble passage was evaluated echocardiographically. The same subjects performed a standard air dive followed by an echosonographic assessment of VGE generation (graded on a scale of 0-5) and distribution. Twenty-three of thirty-four subjects allowed the transpulmonary passage of saline contrast bubbles in the laboratory at rest or after a mild/moderate exercise, and nine of them arterialized after a field dive. All subjects with postdive arterialization had bubble loads reaching or exceeding grade 4B in the right heart. In individuals without transpulmonary passage of saline contrast bubbles, injected either at rest or after an exercise bout, no postdive arterialization was detected. Therefore, postdive VGE arterialization occurs in subjects that meet two criteria: 1) transpulmonary shunting of contrast bubbles at rest or at mild/moderate exercise and 2) VGE generation after a dive reaches the threshold grade. These findings may represent a novel concept in approach to diving, where diving routines will be tailored individually.

  17. DIVING ENERGETICS IN LESSER SCAUP (AYTHYTA AFFINIS, EYTON)

    PubMed

    Stephenson

    1994-05-01

    Mechanical and aerobic energy costs of diving were measured simultaneously by closed-circuit respirometry in six lesser scaup Aythya affinis Eyton (body mass=591±30 g) during bouts of voluntary feeding dives. Durations of dives (td=13.5±1.4 s) and surface intervals (ti=16.3±2.2 s) were within the normal range for ducks diving to 1.5 m depth. Mechanical power output (3.69±0.24 W kg-1) and aerobic power input (29.32±2.47 W kg-1) were both higher than previous estimates. Buoyancy was found to be the dominant factor determining dive costs, contributing 62 % of the mechanical cost of descent and 87 % of the cost of staying at the bottom while feeding. Drag forces, including the contribution from the forward-moving hindlimbs during the recovery stroke of the leg-beat cycle, contributed 27 % and 13 % of the mechanical costs of descent and feeding, respectively. Inertial forces created by net acceleration during descent contributed approximately 11 % during descent but not at all during the feeding phase. Buoyant force at the start of voluntary dives (6.2±0.35 N kg-1) was significantly greater than that measured in restrained ducks (4.9±0.2 N kg-1). Loss of air from the plumage layer and compression due to hydrostatic pressure decreased buoyancy by 32 %. Mechanical work and power output were 1.9 and 2.4 times greater during descent than during the feeding phase. Therefore, energetic costs are strongly affected by dive-phase durations. Estimates by unsteady and steady biomechanical models differ significantly during descent but not during the feeding phase. PMID:9317536

  18. [Asthma and scuba diving Absolute contraindication? in all asthma patients?].

    PubMed

    Coëtmeur, D; Briens, E; Dassonville, J; Vergne, M

    2001-09-01

    Physical and psychological fitness are required for scuba diving, leading to medical contraindications in certain subjects. Asthma, a condition exhibiting increasing prevalence in the general population is currently considered an absolute contraindication for scuba diving by the French Federation for Submarine Sports and Education (FFESSM). There is however no documented evidence demonstrating a higher risk in asthmatic divers. Our English-speaking colleagues have suggested that certain asthmatic subjects could participate in scuba diving sports under certain conditions without any higher risk compared with non-asthmatic divers. We recall here the impact of diving on respiratory function and potential consequences in asthmatic subjects, proposing that the formal contraindication against scuba diving should be maintained for asthmatic patients who experience frequent symptoms (step 2 or more of the International Consensus Report on Diagnosis and Treatment of Asthma) and/or have a baseline obstructive syndrome. It would appear reasonable to discuss the contraindication concerning patients with rare acute episodes and who have a perfectly normal respiratory function. The question of bronchodilator inhalation prior to diving may be a question to debate. However, such a proposal cannot be considered to be valid unless well-conducted studies of the clinical manifestations are available (frequency and severity of the acute episodes, triggering factors) for the diver candidate. Because of the highly restrictive nature of the contraindication notification and the absence of arguments backing up the decision, the question should be put to competent authorities (sports federations, learned societies) in order to ascertain the pathophysiological mechanisms involved and collect reliable epidemiological data before proposing a consensus discussion. This process may lead to the delivery of scuba diving authorizations for selected asthmatic subjects without a higher risk than non

  19. Saturation in coupled oscillators

    NASA Astrophysics Data System (ADS)

    Roman, Ahmed; Hanna, James

    2015-03-01

    We consider a weakly nonlinear system consisting of a resonantly forced oscillator coupled to an unforced oscillator. It has long been known that, for quadratic nonlinearities and a 2:1 resonance between the oscillators, a perturbative solution of the dynamics exhibits a phenomenon known as saturation. At low forcing, the forced oscillator responds, while the unforced oscillator is quiescent. Above a critical value of the forcing, the forced oscillator's steady-state amplitude reaches a plateau, while that of the unforced oscillator increases without bound. We show that, contrary to established folklore, saturation is not unique to quadratically nonlinear systems. We present conditions on the form of the nonlinear couplings and resonance that lead to saturation. Our results elucidate a mechanism for localization or diversion of energy in systems of coupled oscillators, and suggest new approaches for the control or suppression of vibrations in engineered systems.

  20. Nutritional considerations during prolonged exposure to a confined, hyperbaric, hyperoxic environment: recommendations for saturation divers.

    PubMed

    Deb, S K; Swinton, P A; Dolan, E

    2016-01-01

    Saturation diving is an occupation that involves prolonged exposure to a confined, hyperoxic, hyperbaric environment. The unique and extreme environment is thought to result in disruption to physiological and metabolic homeostasis, which may impact human health and performance. Appropriate nutritional intake has the potential to alleviate and/or support many of these physiological and metabolic concerns, whilst enhancing health and performance in saturation divers. Therefore, the purpose of this review is to identify the physiological and practical challenges of saturation diving and consequently provide evidence-based nutritional recommendations for saturation divers to promote health and performance within this challenging environment. Saturation diving has a high-energy demand, with an energy intake of between 44 and 52 kcal/kg body mass per day recommended, dependent on intensity and duration of underwater activity. The macronutrient composition of dietary intake is in accordance with the current Institute of Medicine guidelines at 45-65 % and 20-35 % of total energy intake for carbohydrate and fat intake, respectively. A minimum daily protein intake of 1.3 g/kg body mass is recommended to facilitate body composition maintenance. Macronutrient intake between individuals should, however, be dictated by personal preference to support the attainment of an energy balance. A varied diet high in fruit and vegetables is highly recommended for the provision of sufficient micronutrients to support physiological processes, such as vitamin B12 and folate intake to facilitate red blood cell production. Antioxidants, such as vitamin C and E, are also recommended to reduce oxidised molecules, e.g. free radicals, whilst selenium and zinc intake may be beneficial to reinforce endogenous antioxidant reserves. In addition, tailored hydration and carbohydrate fueling strategies for underwater work are also advised. PMID:26744625

  1. The Lester-Jones tube and scuba diving.

    PubMed

    Mani, Navin; de Carpentier, John

    2009-01-01

    Insertion of a Lester-Jones tube remains the standard treatment for epiphora secondary to canalicular obstruction. We report on a patient requiring removal of his correctly working Lester-Jones tube to allow him to continue his hobby of scuba diving. This particular complication of the Lester-Jones tube has never previously been reported in the literature. Patients with Lester-Jones tubes are unable to perform the valsalva manoeuvre. The valsalva manoeuvre involves blowing the nose against occluded nostrils resulting in a raised pressure in the nose and post-nasal space which is transmitted via the eustachian tubes to the middle ear. The ability to perform a successful valsalva manoeuvre is a prerequisite of scuba diving to equalise middle ear pressure. Inability to equalise middle ear pressure can lead to barotrauma, including pain, rupture of the tympanic membrane and labyrinthine fistula. We recommend that when planning the insertion of a Lester-Jones tube it is wise to enquire whether the patient undertakes scuba diving. If the patient prefers to scuba dive raher than have control of their epiphora, the surgery should be deferred until the patient gives up diving.

  2. Influence of scuba diving on asymptomatic isolated pulmonary bullae.

    PubMed

    Germonpré, Peter; Balestra, Costantino; Pieters, Thierry

    2008-12-01

    Pulmonary blebs and bullae are generally considered an absolute contra-indication for scuba diving, because of a high estimated risk of pulmonary overpressure syndrome due to air-trapping inside the bulla. This is primarily based on a number of retrospective studies and case reports; formal prospective evidence of a higher risk is lacking. We present three cases where a pulmonary bulla was radiographically shown to increase in diameter, seemingly related to scuba diving activity, and causing ultimately a barotraumatic diving accident. These cases provide pathophysiological clues as to how even an isolated, non-ventilated bulla can be the cause of pulmonary barotrauma. The most likely mechanism for this phenomenon is a 'stretching' of the bulla upon ascent from the dive: after a period of compression (Boyle's Law), there is a gradual diffusion of air through the bulla wall, with restoration to its initial size by the end of the dive. Upon ascent, the air diffuses only slowly out of the bulla, causing a temporary increase in diameter and stretching of the bulla wall. This repeated stretching causes the bulla to grow gradually. At one point, the cyst wall may become critically thin and rupture during the ascent. PMID:22692754

  3. Influence of scuba diving on asymptomatic isolated pulmonary bullae.

    PubMed

    Germonpré, Peter; Balestra, Costantino; Pieters, Thierry

    2008-12-01

    Pulmonary blebs and bullae are generally considered an absolute contra-indication for scuba diving, because of a high estimated risk of pulmonary overpressure syndrome due to air-trapping inside the bulla. This is primarily based on a number of retrospective studies and case reports; formal prospective evidence of a higher risk is lacking. We present three cases where a pulmonary bulla was radiographically shown to increase in diameter, seemingly related to scuba diving activity, and causing ultimately a barotraumatic diving accident. These cases provide pathophysiological clues as to how even an isolated, non-ventilated bulla can be the cause of pulmonary barotrauma. The most likely mechanism for this phenomenon is a 'stretching' of the bulla upon ascent from the dive: after a period of compression (Boyle's Law), there is a gradual diffusion of air through the bulla wall, with restoration to its initial size by the end of the dive. Upon ascent, the air diffuses only slowly out of the bulla, causing a temporary increase in diameter and stretching of the bulla wall. This repeated stretching causes the bulla to grow gradually. At one point, the cyst wall may become critically thin and rupture during the ascent.

  4. Hyperbaric oxygen diving affects exhaled molecular profiles in men.

    PubMed

    van Ooij, P J A M; van Hulst, R A; Kulik, W; Brinkman, P; Houtkooper, A; Sterk, P J

    2014-07-01

    Exhaled breath contains volatile organic compounds (VOCs) that are associated with respiratory pathophysiology. We hypothesized that hyperbaric oxygen exposure (hyperoxia) generates a distinguishable VOC pattern. This study aimed to test this hypothesis in oxygen-breathing divers. VOCs in exhaled breath were measured in 10 male divers before and 4h after diving to 9msw (190kPa) for 1h. During the dive they breathed 100% oxygen or air in randomized order. VOCs were determined using two-dimensional gas chromatography with time-of-flight mass spectrometry. Compared to air dives, after oxygen dives there was a significant increase in five VOCs (predominately methyl alkanes). Furthermore, a strong, positive correlation was found between increments in 2,4-dimethyl-hexane and those of 4-ethyl-5-methyl-nonane. Although non-submerged hyperoxia studies on VOCs have been performed, the present study is the first to demonstrate changes in exhaled molecular profiles after submerged oxygen diving. The pathophysiological background might be attributed to either a lipid peroxidation-induced pathway, an inflammatory pathway, or to both.

  5. Respiratory mechanics in men following a deep air dive.

    PubMed

    Catron, P W; Bertoncini, J; Layton, R P; Bradley, M E; Flynn, E T

    1986-08-01

    The mechanical properties of the lungs were measured in 10 men before and after a simulated air dive to 285 ft of seawater (87 m). The objective was to determine whether a dive likely to produce pulmonary bubble emboli would alter lung mechanics. Lung function was measured predive and at 1, 2, 3, 6, 7, and 23 h postdive. Measurements of lung function were also made at identical times on a control day when no dive was made. Each set of measurements included precordial Doppler signals, pulmonary resistance, quasistatic lung compliance, forced vital capacity (FVC), forced expired volume after 1.0 s (FEV 1.0), the ratio of FEV 1.0 to FVC (FEV 1.0/FVC%), and maximal airflow after 50 and 75% of the vital capacity had been expired (Vmax50 and Vmax75, respectively). Base-line measurements of pulmonary resistance and quasistatic compliance were normal in all subjects. FVC and FEV 1.0 were greater than predicted for most subjects and were increased proportionately so that the FEV 1.0/FVC% was normal. Following the dive, bubble signals were heard in four subjects, and two subjects had mild symptoms of decompression sickness. No subject demonstrated any alteration in lung function that could be attributed to the dive. We concluded that stressful decompressions capable of producing "silent" pulmonary bubble emboli do not alter lung mechanics.

  6. Recurrent pulmonary barotrauma in scuba diving and the risks of future hyperbaric exposures: a case report.

    PubMed

    Carpenter, C R

    1997-09-01

    A 27-yr-old male scuba diving student suffered two episodes of pulmonary barotrauma 6 mo. apart after 12-ft training scuba dives. In the interval between these episodes, four uneventful hyperbaric chamber dives occurred. No definite cause or risk factors were identified. A MEDLINE review of diving literature revealed few studies of recurrent pulmonary barotrauma and no studies addressed risks of recurrent pulmonary barotrauma in the hyperbaric oxygen therapy environment following scuba pulmonary barotrauma.

  7. [Breath-hold diving--an increasing adventure sport with medical risks].

    PubMed

    Lindholm, Peter; Gennser, Mikael

    2004-02-26

    Breath-hold diving as a recreational and competitive sports activity is on the increase. In this review physiological limitations and medical risks associated with breath-hold diving are discussed. Specific topics include hypoxia, ascent blackout, hyperventilation, squeeze or barotrauma of descent including effects on the pulmonary system, glossopharyngeal breathing, and decompression illness. It is also concluded that the health requirements for competitive breath-hold diving should follow essentially the same standards as used for SCUBA-diving.

  8. Pump for Saturated Liquids

    NASA Technical Reports Server (NTRS)

    Elliott, D. G.

    1986-01-01

    Boiling liquids pumped by device based on proven components. Expanding saturated liquid in nozzle and diverting its phases along separate paths in liquid/vapor separator raises pressure of liquid. Liquid cooled in process. Pump makes it unnecessary to pressurize cryogenic liquids in order to pump them. Problems of introducing noncondensable pressurizing gas avoided.

  9. [Health hazards associated with flying and diving. ENT aspects].

    PubMed

    Moser, M; Wolf, G

    1990-08-30

    The popularity of scuba diving among the general public and the great increase in air travel are increasingly associated with health problems. In the ENT sector, such problems mainly take the form of barotrauma that can arise from changes in the volume of gases enclosed within body cavities, due to fluctuations in pressure during diving and air travel. More rarely, decompression illness can occur when the required time for decompression is ignored by a diver coming up to the surface, or when a sudden loss of pressure occurs in the cabin of a plane, leading to the liberation of nitrogen dissolved in body fluids. Pathomechanisms, symptoms and treatment of barotrauma affecting the middle and inner ear and the sinuses, together with the effects of decompression errors on the organs of hearing and balance, are described, and suggestions for their prevention given. Fitness for diving and air travel, together with diseases that render these inadvisable, are discussed.

  10. 29 CFR Appendix B to Subpart Y of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart Y... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Pt. 1926, Subpt. Y, App. B Appendix B to Subpart Y of Part 1926—Guidelines for Scientific Diving Note:...

  11. 29 CFR Appendix B to Subpart T to... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T... ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Pt. 1910, Subpt. T, App. B Appendix B to Subpart T to Part 1910—Guidelines for Scientific Diving...

  12. Dolphin lung collapse and intramuscular circulation during free diving: evidence from nitrogen washout.

    PubMed

    Ridgway, S H; Howard, R

    1979-12-01

    Intramuscular nitrogen tensions in Tursiops truncatus after a schedule of repetitive ocean dives suggest a lung collapse depth of about 70 meters and suggest that intramuscular circulation is maintained during unrestrained diving in the open ocean. Therefore, the bottle-nosed dolphin is not protected by lung collapse from the decompression hazards of dives to depths shallower than 70 meters. PMID:505001

  13. Investigation of the potential for vascular bubble formation in a repetitively diving dolphin.

    PubMed

    Houser, D S; Dankiewicz-Talmadge, L A; Stockard, T K; Ponganis, P J

    2010-01-01

    The production of venous gas emboli (VGE) resulting from altered dive behavior is postulated as contributing to the stranding of beaked whales exposed to mid-frequency active sonar. To test whether nitrogen gas uptake during repetitive breath-hold diving is sufficient for asymptomatic VGE formation in odontocetes, a bottlenose dolphin (Tursiops truncatus Montagu) was trained to perform 10-12 serial dives with 60 s surface intervals to depths of 30, 50, 70 or 100 m. The dolphin remained at the bottom depth for 90 s on each dive. Doppler and/or two-dimensional imaging ultrasound did not detect VGE in the portal and brachiocephalic veins following a dive series. Van Slyke analyses of serial, post-dive blood samples drawn from the fluke yielded blood nitrogen partial pressure (P(N(2))) values that were negligibly different from control samples. Mean heart rate (HR; +/-1 s.d.) recorded during diving was 50+/-3 beats min(-1) and was not significantly different between the 50, 70 and 100 m dive sessions. The absence of VGE and elevated blood P(N(2)) during post-dive periods do not support the hypothesis that N(2) supersaturation during repetitive dives contributes to VGE formation in the dolphin. The diving HR pattern and the presumed rapid N(2) washout during the surface-interval tachycardia probably minimized N(2) accumulation in the blood during dive sessions.

  14. Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma

    PubMed Central

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components. PMID:23984113

  15. Magnitude and rate of accommodation in diving and nondiving birds.

    PubMed

    Sivak, J G; Hildebrand, T; Lebert, C

    1985-01-01

    Accommodation was measured in a variety of waterfowl by projecting parallel low power helium-neon laser beams through the pupils of excised eyes placed in saline. The posterior globe was removed, allowing the beams, refracted only by the lens, to focus well behind the eye. Electrical stimulation of the ciliary muscle results in accommodative movement of the focal point toward the eye. Study of video recordings show that diving ducks (Mergus cucullatus and Bucephala clangala) can accommodate the 70-80 D needed to focus light on the retina when the eye is in water. Diving and nondiving species are compared in amount and rate of accommodation. PMID:4049742

  16. Methods of deep dives in whole ice cover conditions

    NASA Astrophysics Data System (ADS)

    Sagalevich, A. M.

    2016-05-01

    The essence of methodological and engineering questions solved during the preparation and implementation of historic dives of the manned submersibles Mir-1 and Mir-2, allowing humans to see the bottom of the North Pole at a depth of 4300 m, are described together with innovative developments in underwater navigation, as well as the Mir's propulsion, ballast, and other systems that ensured the safety of the dives. These innovative methods have opened up the Arctic's underice space for scientific research and practical exploration for minerals with the direct participation of scientists and specialists.

  17. Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma.

    PubMed

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components. PMID:23984113

  18. Value of bronchial challenge in scuba diving candidates.

    PubMed

    Badier, M; Guillot, C; Delpierre, S; Fornaris, E; Jacquin, M

    2000-12-01

    Bronchial challenges were effected with carbachol in 76 subjects who were candidates for a scuba diving group. Bronchial reactivity was assessed through airway resistance and forced expiratory volume in 1 sec (FEV1) measurements. Medical interrogation had revealed symptoms of recent (RA) or ancient (AA) asthma, or allergic rhinitis (AL). Nearly half of the subjects (47%) presented bronchial hyperresponsiveness (BHR), which was much more frequent in the RA group, but whose strength did not depend on clinical presentation. Prevalence of BHR was fairly high (36%) in the AL group. BHR constituted a contraindication to scuba diving because it may promote pulmonary barotrauma.

  19. Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma.

    PubMed

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components.

  20. [Scuba diving as a rehabilitation approach in paraplegia].

    PubMed

    Novak, H F; Ladurner, G

    1999-08-01

    In a group of nine paraplegics a significant increase of pulmonary vital capacity could be shown after participating in a two weeks Scuba (self containing underwater breathing apparatus) diving training. During dives and for a certain time afterwards, a satisfyingly sensed reduction of painful muscle spasms occurred. A comparable group of sailing paraplegics did not show any significant changes within the same time. Because of strict ability criteria combined with an enormous effort of care to meet all security precautions this approach to neurorehabilitation can be offered to a limited number of patients only.

  1. Effect of repetitive SCUBA diving on humoral markers of endothelial and central nervous system integrity.

    PubMed

    Bilopavlovic, Nada; Marinovic, Jasna; Ljubkovic, Marko; Obad, Ante; Zanchi, Jaksa; Pollock, Neal W; Denoble, Petar; Dujic, Zeljko

    2013-07-01

    During SCUBA diving decompression, there is a significant gas bubble production in systemic veins, with rather frequent bubble crossover to arterial side even in asymptomatic divers. The aim of the current study was to investigate potential changes in humoral markers of endothelial and brain damage (endothelin-1, neuron-specific enolase and S-100β) after repetitive SCUBA diving with concomitant assessment of venous gas bubble production and subsequent arterialization. Sixteen male divers performed four open-water no-decompression dives to 18 msw (meters of sea water) lasting 49 min in consecutive days during which they performed moderate-level exercise. Before and after dives 1 and 4 blood was drawn, and bubble production and potential arterialization were echocardiographically evaluated. In addition, a control dive to 5 msw was performed with same duration, water temperature and exercise load. SCUBA diving to 18 msw caused significant bubble production with arterializations in six divers after dive 1 and in four divers after dive 4. Blood levels of endothelin-1 and neuron-specific enolase did not change after diving, but levels of S-100β were significantly elevated after both dives to 18 msw and a control dive. Creatine kinase activity following a control dive was also significantly increased. Although serum S-100β levels were increased after diving, concomitant increase of creatine kinase during control, almost bubble-free, dive suggests the extracranial release of S-100β, most likely from skeletal muscles. Therefore, despite the significant bubble production and sporadic arterialization after open-water dives to 18 msw, the current study found no signs of damage to neurons or the blood-brain barrier.

  2. The cardiovascular and endocrine responses to voluntary and forced diving in trained and untrained rats

    PubMed Central

    DiNovo, Karyn. M.; Connolly, Tiffanny M.

    2010-01-01

    The mammalian diving response, consisting of apnea, bradycardia, and increased total peripheral resistance, can be modified by conscious awareness, fear, and anticipation. We wondered whether swim and dive training in rats would 1) affect the magnitude of the cardiovascular responses during voluntary and forced diving, and 2) whether this training would reduce or eliminate any stress due to diving. Results indicate Sprague-Dawley rats have a substantial diving response. Immediately upon submersion, heart rate (HR) decreased by 78%, from 453 ± 12 to 101 ± 8 beats per minute (bpm), and mean arterial pressure (MAP) decreased 25%, from 143 ± 1 to 107 ± 5 mmHg. Approximately 4.5 s after submergence, MAP had increased to a maximum 174 ± 3 mmHg. Blood corticosterone levels indicate trained rats find diving no more stressful than being held by a human, while untrained rats find swimming and diving very stressful. Forced diving is stressful to both trained and untrained rats. The magnitude of bradycardia was similar during both voluntary and forced diving, while the increase in MAP was greater during forced diving. The diving response of laboratory rats, therefore, appears to be dissimilar from that of other animals, as most birds and mammals show intensification of diving bradycardia during forced diving compared with voluntary diving. Rats may exhibit an accentuated antagonism between the parasympathetic and sympathetic branches of the autonomic nervous system, such that in the autonomic control of HR, parasympathetic activity overpowers sympathetic activity. Additionally, laboratory rats may lack the ability to modify the degree of parasympathetic outflow to the heart during an intense cardiorespiratory response (i.e., the diving response). PMID:19923359

  3. Seabird diving behaviour reveals the functional significance of shelf-sea fronts as foraging hotspots

    NASA Astrophysics Data System (ADS)

    Cox, S. L.; Miller, P. I.; Embling, C. B.; Scales, K. L.; Bicknell, A. W. J.; Hosegood, P. J.; Morgan, G.; Ingram, S. N.; Votier, S. C.

    2016-09-01

    Oceanic fronts are key habitats for a diverse range of marine predators, yet how they influence fine-scale foraging behaviour is poorly understood. Here, we investigated the dive behaviour of northern gannets Morus bassanus in relation to shelf-sea fronts. We GPS (global positioning system) tracked 53 breeding birds and examined the relationship between 1901 foraging dives (from time-depth recorders) and thermal fronts (identified via Earth Observation composite front mapping) in the Celtic Sea, Northeast Atlantic. We (i) used a habitat-use availability analysis to determine whether gannets preferentially dived at fronts, and (ii) compared dive characteristics in relation to fronts to investigate the functional significance of these oceanographic features. We found that relationships between gannet dive probabilities and fronts varied by frontal metric and sex. While both sexes were more likely to dive in the presence of seasonally persistent fronts, links to more ephemeral features were less clear. Here, males were positively correlated with distance to front and cross-front gradient strength, with the reverse for females. Both sexes performed two dive strategies: shallow V-shaped plunge dives with little or no active swim phase (92% of dives) and deeper U-shaped dives with an active pursuit phase of at least 3 s (8% of dives). When foraging around fronts, gannets were half as likely to engage in U-shaped dives compared with V-shaped dives, independent of sex. Moreover, V-shaped dive durations were significantly shortened around fronts. These behavioural responses support the assertion that fronts are important foraging habitats for marine predators, and suggest a possible mechanistic link between the two in terms of dive behaviour. This research also emphasizes the importance of cross-disciplinary research when attempting to understand marine ecosystems.

  4. Seabird diving behaviour reveals the functional significance of shelf-sea fronts as foraging hotspots

    PubMed Central

    Miller, P. I.; Embling, C. B.; Bicknell, A. W. J.; Hosegood, P. J.; Morgan, G.; Ingram, S. N.

    2016-01-01

    Oceanic fronts are key habitats for a diverse range of marine predators, yet how they influence fine-scale foraging behaviour is poorly understood. Here, we investigated the dive behaviour of northern gannets Morus bassanus in relation to shelf-sea fronts. We GPS (global positioning system) tracked 53 breeding birds and examined the relationship between 1901 foraging dives (from time-depth recorders) and thermal fronts (identified via Earth Observation composite front mapping) in the Celtic Sea, Northeast Atlantic. We (i) used a habitat-use availability analysis to determine whether gannets preferentially dived at fronts, and (ii) compared dive characteristics in relation to fronts to investigate the functional significance of these oceanographic features. We found that relationships between gannet dive probabilities and fronts varied by frontal metric and sex. While both sexes were more likely to dive in the presence of seasonally persistent fronts, links to more ephemeral features were less clear. Here, males were positively correlated with distance to front and cross-front gradient strength, with the reverse for females. Both sexes performed two dive strategies: shallow V-shaped plunge dives with little or no active swim phase (92% of dives) and deeper U-shaped dives with an active pursuit phase of at least 3 s (8% of dives). When foraging around fronts, gannets were half as likely to engage in U-shaped dives compared with V-shaped dives, independent of sex. Moreover, V-shaped dive durations were significantly shortened around fronts. These behavioural responses support the assertion that fronts are important foraging habitats for marine predators, and suggest a possible mechanistic link between the two in terms of dive behaviour. This research also emphasizes the importance of cross-disciplinary research when attempting to understand marine ecosystems. PMID:27703698

  5. Effect of diving and diving hoods on the bacterial flora of the external ear canal and skin.

    PubMed Central

    Brook, I; Coolbaugh, J C; Williscroft, R G

    1982-01-01

    The bacterial flora of the external ear canals and posterior auricular skin surfaces were investigated in a group of 26 divers after 25 dry-suit dives in harbor water and 20 dry-suit dives in clear test tank test. A control group of 16 divers wore rubber hoods 19 times for a similar period (25 to 30 min) but did not dive. The protective effect of 2% acetic acid was tested by instilling it in the left ear of 14 divers and 8 nondivers. Staphylococcus epidermidis, Propionibacterium acnes, alpha-hemolytic streptococci, and enteric gram-negative rods were the predominant isolates from skin and ear samples. After the divers dove or after they wore hoods without going in the water, there was a substantial increase in the number of these organisms on the skin (46.9%) or in the external ears (43.8%) of the divers. However, an increase in the bacterial counts in the external ear canals occurred in only 13.6% of the individuals treated prophylactically with acetic acid drops. Although no gram-negative rods were recovered from the skin or external ear canals of divers in clear tank water, 23 strains were isolated after the dives in harbor water. Identical gram-negative isolates also were recovered from the harbor water. Gram-negative organisms also were recovered from three newly acquired skin lacerations, where they persisted for at least 24 h. Our data show the acquisition of gram-negative rods when dives were made in polluted water. The data also demonstrate the increase in bacterial counts that occurs when rubber diving rods are worn (in or out of water) and that this increase can be controlled by pretreatment of ears with acetic acid. PMID:7096559

  6. A red orange extract modulates the vascular response to a recreational dive: a pilot study on the effect of anthocyanins on the physiological consequences of scuba diving.

    PubMed

    Balestra, C; Cimino, F; Theunissen, S; Snoeck, T; Provyn, S; Canali, R; Bonina, A; Virgili, F

    2016-09-01

    Nutritional antioxidants have been proposed as an expedient strategy to counter the potentially deleterious effects of scuba diving on endothelial function, flow-mediated dilation (FMD) and heart function. Sixteen volunteers performing a single standard dive (20 min at 33 m) according to US Navy diving procedures were randomly assigned to two groups: one was administered with two doses of 200 mg of an anthocyanins (AC)-rich extract from red oranges, 12 and 4 h before diving. Anthocyanins supplementation significantly modulated the effects of diving on haematocrit, body water distribution and FMD. AC administration significantly reduces the potentially harmful endothelial effects of a recreational single dive. The lack of any significant effect on the most common markers of plasma antioxidant capacity suggests that the mechanism underlying this protective activity is independent of the putative antioxidant effect of AC and possibly involves cellular signalling modulation of the response to high oxygen.

  7. Effects of food, water depth, and temperature on diving activity of larval Anopheles gambiae sensu stricto: evidence for diving to forage.

    PubMed

    Phelan, Conan; Roitberg, Bernard D

    2013-12-01

    Anopheles gambiae larvae have frequently been observed to dive, but the ecology of this behavior has not been extensively examined. We manipulated food level, water depth, and temperature for individually-reared larvae and observed diving activity. Larvae dived more often under low food, which suggests that they dive to forage. There was only weak evidence for effects of water depth or temperature on diving. Experimental results are discussed in the context of energy budgets. Understanding larval ecology of this species is important for predicting how it will respond to environmental change. Further study is needed to assess the role that larval diving plays in both feeding ecology and thermal regulation of this and other medically important species.

  8. Capillary saturation and desaturation.

    PubMed

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment. PMID:26764820

  9. Persistent (patent) foramen ovale (PFO): implications for safe diving.

    PubMed

    Germonpré, Peter

    2015-06-01

    Diving medicine is a peculiar specialty. There are physicians and scientists from a wide variety of disciplines with an interest in diving and who all practice 'diving medicine': the study of the complex whole-body physiological changes and interactions upon immersion and emersion. To understand these, the science of physics and molecular gas and fluid movements comes into play. The ultimate goal of practicing diving medicine is to preserve the diver's health, both during and after the dive. Good medicine starts with prevention. For most divers, underwater excursions are not a professional necessity but a hobby; avoidance of risk is generally a much better option than risk mitigation or cure. However, prevention of diving illnesses seems to be even more difficult than treating those illnesses. The papers contained in this issue of DHM are a nice mix of various aspects of PFO that divers are interested in, all of them written by specialist doctors who are avid divers themselves. However, diving medicine should also take advantage of research from the "non-diving" medicine community, and PFO is a prime example. Cardiology and neurology have studied PFO for as long, or even longer than divers have been the subjects of PFO research, and with much greater numbers and resources. Unexplained stroke has been associated with PFO, as has severe migraine with aura. As the association seems to be strong, investigating the effect of PFO closure was a logical step. Devices have been developed and perfected, allowing now for a relatively low-risk procedure to 'solve the PFO problem'. However, as with many things in science, the results have not been as spectacular as hoped for: patients still get recurrences of stroke, still have migraine attacks. The risk-benefit ratio of PFO closure for these non-diving diseases is still debated. For diving, we now face a similar problem. Let there be no doubt that PFO is a pathway through which venous gas emboli (VGE) can arterialize, given

  10. Perceptions amongst Tasmanian recreational scuba divers of the value of a diving medical.

    PubMed

    Baines, Carol

    2013-12-01

    An online survey was offered to recreational divers in Tasmania to ascertain if they have an understanding of how pressure affects their health and if they considered an annual dive medical necessary. A total of 98 recreational divers completed the survey, five of these had never had a dive medical while 74 felt that if they passed their dive medical they do not have any potential illness. Sixty five saw the dive medical as a comprehensive health check. This project provided an insight to Tasmanian recreational divers' understanding of and attitude towards the value of a dive medical.

  11. Perceptions amongst Tasmanian recreational scuba divers of the value of a diving medical.

    PubMed

    Baines, Carol

    2013-12-01

    An online survey was offered to recreational divers in Tasmania to ascertain if they have an understanding of how pressure affects their health and if they considered an annual dive medical necessary. A total of 98 recreational divers completed the survey, five of these had never had a dive medical while 74 felt that if they passed their dive medical they do not have any potential illness. Sixty five saw the dive medical as a comprehensive health check. This project provided an insight to Tasmanian recreational divers' understanding of and attitude towards the value of a dive medical. PMID:24510335

  12. Pulmonary edema following closed-circuit oxygen diving and strenuous swimming.

    PubMed

    Shupak, Avi; Guralnik, Ludmila; Keynan, Yoav; Yanir, Yoav; Adir, Yochai

    2003-11-01

    Acute pulmonary edema may be induced by diving and strenuous swimming. We report the case of a diver using closed-circuit, scuba equipment who developed acute dyspnea, hemoptysis, and hypoxemia following a dive in 18 degreesC (64.4 degrees F) water and physical exertion during the swim back to shore. With the growing popularity of recreational scuba diving, emergency physicians are liable to be faced with increasing numbers of diving-related medical problems. Diving-induced pulmonary edema should be included in the differential diagnosis of acute hypoxemia, sometimes accompanied by acid-base abnormalities, when this is seen in a diver.

  13. Inner ear barotrauma in scuba divers. A long-term follow-up after continued diving.

    PubMed

    Parell, G J; Becker, G D

    1993-04-01

    Divers who suffer inner ear barotrauma are usually counseled to permanently avoid diving, reasoning that the injured inner ear is at increased risk of further damage. Twenty patients who suffered inner ear barotrauma while diving, but continued to dive against medical advice, were assessed on an interim basis for 1 to 12 years. As difficulty equalizing the ears during the barotraumatic event was a universal finding, prior to resuming diving, all patients were reinstructed on methods of maximizing eustachian tube function. No further deterioration of cochleovestibular function was noted. Based on these preliminary results, we conclude that recommending no further diving after inner ear barotrauma may be unnecessarily restrictive.

  14. 33 CFR 89.25 - Waters upon which Inland Rules 9(a)(ii), 14(d), and 15(b) apply.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Point. (g) Flint River. (h) Chattachoochee River. (i) The Apalachicola River above its confluence with...), and 15(b) apply. Inland Rules 9(a)(ii), 14(d), and 15(b) apply on the Great Lakes, the Western Rivers, and the following specified waters: (a) Tennessee-Tombigbee Waterway. (b) Tombigbee River. (c)...

  15. 33 CFR 89.25 - Waters upon which Inland Rules 9(a)(ii), 14(d), and 15(b) apply.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Point. (g) Flint River. (h) Chattachoochee River. (i) The Apalachicola River above its confluence with...), and 15(b) apply. Inland Rules 9(a)(ii), 14(d), and 15(b) apply on the Great Lakes, the Western Rivers, and the following specified waters: (a) Tennessee-Tombigbee Waterway. (b) Tombigbee River. (c)...

  16. 33 CFR 89.25 - Waters upon which Inland Rules 9(a)(ii), 14(d), and 15(b) apply.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Point. (g) Flint River. (h) Chattachoochee River. (i) The Apalachicola River above its confluence with...), and 15(b) apply. Inland Rules 9(a)(ii), 14(d), and 15(b) apply on the Great Lakes, the Western Rivers, and the following specified waters: (a) Tennessee-Tombigbee Waterway. (b) Tombigbee River. (c)...

  17. 33 CFR 89.25 - Waters upon which Inland Rules 9(a)(ii), 14(d), and 15(b) apply.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Point. (g) Flint River. (h) Chattachoochee River. (i) The Apalachicola River above its confluence with...), and 15(b) apply. Inland Rules 9(a)(ii), 14(d), and 15(b) apply on the Great Lakes, the Western Rivers, and the following specified waters: (a) Tennessee-Tombigbee Waterway. (b) Tombigbee River. (c)...

  18. 33 CFR 89.25 - Waters upon which Inland Rules 9(a)(ii), 14(d), and 15(b) apply.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Point. (g) Flint River. (h) Chattachoochee River. (i) The Apalachicola River above its confluence with...), and 15(b) apply. Inland Rules 9(a)(ii), 14(d), and 15(b) apply on the Great Lakes, the Western Rivers, and the following specified waters: (a) Tennessee-Tombigbee Waterway. (b) Tombigbee River. (c)...

  19. Muscle Energy Stores and Stroke Rates of Emperor Penguins: Implications for Muscle Metabolism and Dive Performance

    PubMed Central

    Williams, Cassondra L.; Sato, Katsufumi; Shiomi, Kozue; Ponganis, Paul J.

    2016-01-01

    In diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. During complete ischemia, ATP production is dependent on the size of the myoglobin oxygen (O2) store and the concentrations of phosphocreatine (PCr) and glycogen (Gly). Therefore, we measured PCr and Gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle O2 and those energy stores under conditions of complete ischemia and a previously determined muscle metabolic rate. We also analyzed stroke rate to assess muscle workload variation during dives and evaluate potential limitations on the model. Measured PCr and Gly concentrations, 20.8 and 54.6 mmol kg−1, respectively, were similar to published values for non-diving animals. The model demonstrated that PCr and Gly provide a large anaerobic energy store, even for dives longer than 20 min. Stroke rate varied throughout the dive profile indicating muscle workload was not constant during dives as was assumed in the model. The stroke rate during the first 30 seconds of dives increased with increased dive depth. In extremely long dives, lower overall stroke rates were observed. Although O2 consumption and energy store depletion may vary during dives, the model demonstrated that PCr and Gly, even at concentrations typical of terrestrial birds and mammals, are a significant anaerobic energy store and can play an important role in the emperor penguin’s ability to perform long dives. PMID:22418705

  20. Diving bradycardia of elderly Korean women divers, haenyeo, in cold seawater: a field report

    PubMed Central

    LEE, Joo-Young; LEE, Hyo-Hyun; KIM, Siyeon; JANG, Young-Joon; BAEK, Yoon-Jeong; KANG, Kwon-Yong

    2015-01-01

    The purpose of the present field study was to explore diving patterns and heart rate of elderly Korean women divers (haenyeo) while breath-hold diving in cold seawater. We hypothesized that the decreasing rate in heart rate of elderly haenyeos during breath-hold diving was greater and total diving time was shorter than those of young haenyeos from previous studies. Nine haenyeos participated in a field study [68 ± 10 yr in age, ranged from 56 to 83 yr] at a seawater temperature of 10 to 13 °C. Average total diving time including surface swimming time between dives was 253 ± 73 min (155–341 min). Total frequency of dives was 97 ± 28 times and they dived 23 ± 8 times per hour. All haenyeos showed diving bradycardia with a decreased rate of 20 ± 8% at the bottom time (101 ± 20 bpm) when compared to surface swimming time (125 ± 16 bpm) in the sea. Older haenyeos among the nine elderly haenyeos had shorter diving time, less diving frequencies, and lower heart rate at work (p<0.05). These reductions imply that haenyeos voluntarily adjust their workload along with advancing age and diminished cardiovascular functions. PMID:26632118

  1. Diving behaviour of whale sharks in relation to a predictable food pulse.

    PubMed

    Graham, Rachel T; Roberts, Callum M; Smart, James C R

    2006-02-22

    We present diving data for four whale sharks in relation to a predictable food pulse (reef fish spawn) and an analysis of the longest continuous fine-resolution diving record for a planktivorous shark. Fine-resolution pressure data from a recovered pop-up archival satellite tag deployed for 206 days on a whale shark were analysed using the fast Fourier Transform method for frequency domain analysis of time-series. The results demonstrated that a free-ranging whale shark displays ultradian, diel and circa-lunar rhythmicity of diving behaviour. Whale sharks dive to over 979.5 m and can tolerate a temperature range of 26.4 degrees C. The whale sharks made primarily diurnal deep dives and remained in relatively shallow waters at night. Whale shark diving patterns are influenced by a seasonally predictable food source, with shallower dives made during fish spawning periods.

  2. Diving behaviour of whale sharks in relation to a predictable food pulse

    PubMed Central

    Graham, Rachel T; Roberts, Callum M; Smart, James C.R

    2005-01-01

    We present diving data for four whale sharks in relation to a predictable food pulse (reef fish spawn) and an analysis of the longest continuous fine-resolution diving record for a planktivorous shark. Fine-resolution pressure data from a recovered pop-up archival satellite tag deployed for 206 days on a whale shark were analysed using the fast Fourier Transform method for frequency domain analysis of time-series. The results demonstrated that a free-ranging whale shark displays ultradian, diel and circa-lunar rhythmicity of diving behaviour. Whale sharks dive to over 979.5 m and can tolerate a temperature range of 26.4 °C. The whale sharks made primarily diurnal deep dives and remained in relatively shallow waters at night. Whale shark diving patterns are influenced by a seasonally predictable food source, with shallower dives made during fish spawning periods. PMID:16849222

  3. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422... decompression. (f) Hand-held power tools and equipment. (1) Hand-held electrical tools and equipment shall be...

  4. Beginning Skin and Scuba Diving, Physical Education: 5551.69.

    ERIC Educational Resources Information Center

    Roberts, Millie

    This course outline is a guide for teaching the principles and basic fundamentals of beginning skin and scuba diving in grades 7-12. The course format includes lectures, skills practice, films, and tests that focus on mastery of skills and understanding correct usage of skin and scuba equipment. Course content includes the following: (a) history,…

  5. OVERVIEW OF DIVE TRAINER SIMULATOR FROM FIRST FLOOR LEVEL SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF DIVE TRAINER SIMULATOR FROM FIRST FLOOR LEVEL SHOWING HYDRAULIC EQUIPMENT, SUPPORTS AND FOUNDATION BLOCKS. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI

  6. OVERVIEW OF DIVE TRAINER SIMULATOR AT SECOND FLOOR LEVEL SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF DIVE TRAINER SIMULATOR AT SECOND FLOOR LEVEL SHOWING CONTROL CENTER CAB. VIEW FACING WEST/NORTHWEST - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI

  7. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT General Provisions §...

  8. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT General Provisions §...

  9. Descriptive Analysis of the Rip Entry in Competitive Diving.

    ERIC Educational Resources Information Center

    Brown, Janet G.; And Others

    1984-01-01

    Different types of diving entries were filmed both above water and underwater to help identify factors which enable divers to enter the water without apparent splash. Anthropometric measures of subjects were taken to determine body streamlining. Results are presented. (Author/DF)

  10. Cardiac alterations induced by a fish-catching diving competition.

    PubMed

    Gargne, O; Joulia, F; Golé, Y; Coulange, M; Bessereau, J; Fontanari, P; Desruelle, A-V; Gavarry, O; Boussuges, A

    2012-06-01

    Cardiac changes induced by repeated breath-hold diving were investigated after a fish-catching diving competition. Eleven healthy subjects carried out repeated breath-hold dives at a mean maximal depth of 20 ± 2.7 msw (66 ± 9 fsw) during 5 h. One hour after the competition, the body mass loss was -1.7 ± 0.5 kg. Most of the breath-hold divers suffered from cold and although the core temperature remained normal, a decrease in cutaneous temperature was recorded in the extremities. Systolic blood pressure was reduced in both upper and lower limbs. Heart rate was unchanged, but left ventricular (LV) stroke volume was reduced leading to a decrease in cardiac output (-20%). Left atrial and LV diameters were significantly decreased. LV filling was assessed on a trans-mitral profile. An increase in the contribution of the atrial contraction to LV filling was observed. Right cavity diameters were increased. The cardiac autonomic alterations were in favor of sympathetic hyperactivity. After a fish-catching diving competition in cold water, alterations suggesting dehydration, contraction in plasma volume and sympathetic hyperactivity were observed. Furthermore, enlargements of right cavities were in favor of right ventricular strains. Repeated apnea and swimming in cold water may account for these alterations. PMID:20738824

  11. Onset of and recovery from diving bradycardia in ducks

    PubMed Central

    Butler, P. J.; Jones, D. R.

    1968-01-01

    1. No evidence was found of a `postural reflex' in ducks. Neither the position of the head nor the water temperature affected the cardiac response to diving. 2. In ducks with access to air through a tracheal cannula, submersion did not invariably cause apnoea until the water level reached the glottis. Heart rate was closely related to respiratory frequency, and bradycardia did not occur during submersion unless there was a reduction in respiratory frequency or a cessation of ventilation altogether. 3. When apnoea and bradycardia did occur during submersion, the first inspiration upon surfacing was 2-3 times larger than normal and was accompanied by an instantaneous rise in heart rate. 4. Atropinization or cold block of the vagus abolished diving bradycardia. Only one vagal trunk was involved in cardiac chronotropic control at any one time. This vagal trunk also appeared to be more important in control of respiratory frequency. 5. β-adrenergic receptor blockade did not affect either diving bradycardia or post-dive tachycardia. 6. The results show that the cardiac chronotropic response both during and after submergence is controlled solely by changes in parasympathetic vagal activity. PMID:5652875

  12. ENT function in a 14-days guinness scuba dive.

    PubMed

    Revelli, L; D'Alatri, L; Scorpecci, A; D'Amore, A; De Corso, E; Lombardi, C P; Fetoni, A R

    2012-01-01

    Scuba diving is known to affect the rhino-pharyngo-tubaric district (RPT unit). The aim of the study was to document function modifications of the RPT unit in 6 Italian divers (3 men and 3 women) who lived for 14 days consecutively at a depth of 8-10 m, breathing air (21% oxygen) at a pressure ranging between 1.8 and 2 ATA. RPT and inner ear assessment were carried out before the dive (TIME 0) and 24 h (TIME 1) after resurfacing, in order to investigate diving-related RPT and inner ear alterations. Physical examination after resurfacing revealed: fungal external otitis, otoscopic findings consistent with middle ear barotraumas and rhinosinusitis. Rhino-manometry showed a remarkable increase in inspiratory nasal flow and a substantial decrease in nasal resistance. No epithelial cell disruption was retrieved comparing pre and post resurfacing samples. Post-diving tubaric dysfunction was found. Pure tone audiometry revealed a bilateral 40 dB HL hearing loss at 4 kHz in 1 diver. Relevant PTA functions did not seem to be affected by the experiment, no remarkable changes were found at the Sensory Organisation Test and at the Motor Control Test. The 14-day underwater period had a positive effect on nasal flows and resistances.

  13. Scuba diving accidents in Sweden 1960--1976.

    PubMed

    Carlsson, K; Lidholm, S O; Maehly, A C

    1978-01-01

    Thirty "scuba" diving accidents (29 of them fatal) which occurred in Sweden during 1960--76 are listed. Nine of these are described in some detail. The probable causes of these accidents are evaluated, and suggestions for prophylactic measures are made.

  14. Environmental stress on diving-induced platelet activation.

    PubMed

    Bosco, G; Yang, Z J; Savini, F; Nubile, G; Data, P G; Wang, J P; Camporesi, E M

    2001-01-01

    Platelet activation has been suggested to play an important role in the pathogenesis of prethrombotic states and thus may be responsible for decompression illness during compressed air (scuba) diving. To investigate the effect of physical, mental, and environmental stress on platelet activation during immersion in ice-cold water, we examined 10 male breath-hold divers (BHD), 10 elite BHD (eBHD), and 10 scuba divers during immersion in an ice-covered lake at moderate altitude. Platelet activation was examined by surface expression of activation-dependent glycoproteins CD62p, CD63, and CD42a with flow cytometry 10 min before and 1 min and again 24 h after diving. Plasma epinephrine level was also measured. In addition, the relationship between the activated platelets and the epinephrine level was evaluated. The percentage of platelet activation increased from 2.1 +/- 0.4 to 5.7 +/- 0.3, 1.8 +/- 0.3 to 12.9 +/- 0.8, and 3.7 +/- 0.9 to 31.2 +/- 0.8 in BHD, eBHD, and scuba divers, respectively. The percentage of platelet activation returned to pre-immersion levels in BHD and eBHD divers 24 h after diving, but was still higher in scuba divers. A positive relationship exists between the plasma epinephrine level and the percentage of the platelet activation. This study suggests that physical and mental stress enhance platelet activation during diving in ice-cold water.

  15. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means capable of supporting the diver shall be provided for entering and exiting the water. (2) The means provided for exiting the water shall extend below the water surface. (3) A means shall be provided to assist...

  16. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means capable of supporting the diver shall be provided for entering and exiting the water. (2) The means provided for exiting the water shall extend below the water surface. (3) A means shall be provided to assist...

  17. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means capable of supporting the diver shall be provided for entering and exiting the water. (2) The means provided for exiting the water shall extend below the water surface. (3) A means shall be provided to assist...

  18. 29 CFR 1910.423 - Post-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diver to report any physical problems or adverse physiological effects including symptoms of... shall instruct the diver to remain awake and in the vicinity of the decompression chamber which is at... be: (i) Dual-lock; (ii) Multiplace; and (iii) Located within 5 minutes of the dive location. (4)...

  19. 29 CFR 1910.423 - Post-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diver to report any physical problems or adverse physiological effects including symptoms of... shall instruct the diver to remain awake and in the vicinity of the decompression chamber which is at... be: (i) Dual-lock; (ii) Multiplace; and (iii) Located within 5 minutes of the dive location. (4)...

  20. A Measurement of "g" Using Alexander's Diving Bell

    ERIC Educational Resources Information Center

    Quiroga, M.; Martinez, S.; Otranto, S.

    2010-01-01

    This paper describes a very simple exercise using an inverted test tube pushed straight down into a column of water to determine the free-fall acceleration "g". The exercise employs the ideal gas law and only involves the measurement of the displacement of the bottom of the "diving bell" and the water level inside the tube with respect to the…