The physiopathology consequences of hypoxia during breath-hold diving are a matter of debate. Adenosine (AD), an ATP derivative, is suspected to be implicated in the adaptive cardiovascular response ...to apnea, because of its vasodilating and bradycardic properties, two clinical manifestations observed during voluntary apnea. The aim of this study was to evaluate the adenosine response to apnea-induced hypoxia in trained spearfishermen (SFM) who are used to perform repetitive dives for 4–5 h. Twelve SFM (11 men and 1 woman, mean age 41 ± 3 years, apnea experience: 18 ± 9 years) and 10 control (CTL) subjects (age 44 ± 7 years) were enrolled in the study. Subjects were asked to main a dry static apnea and stopped it when they began the struggle phase (average duration: SFM 120 ± 78 s, CTL 78 ± 12 s). Capillary blood samples were collected at baseline and immediately after the apnea and analyzed for standard parameters and adenosine blood concentration (ADb). Heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressures were also recorded continuously during the apnea. During the apnea, an increase in SBP and DBP and a decrease in HR were observed in both SFM and CTL. At baseline, ADb was higher in SFM compared with CTL (1.05 ± 0.2 vs. 0.73 ± 0.11 μM,
p
< 0.01). ADb increased significantly at the end of the apnea in both groups, but the increase was significantly greater in SFM than in controls (+90.4 vs. +12%,
p
< 0.01). Importantly, in SFM, we also observed significant correlations between ADb and HR (
R
= −0.8,
p
= 0.02), SpO
2
(
R
= −0.69,
p
= 0.01), SBP (
R
= −0.89,
p
= 0.02), and DBP (
R
= −0.68,
p
= 0.03). Such associations were absent in CTL. The adenosine release during apnea was associated with blood O
2
saturation and cardiovascular parameters in trained divers but not in controls. These data therefore suggest that adenosine may play a major role in the adaptive cardiovascular response to apnea and could reflect the level of training.
Within the components of Scuba diving there are similarities with meditation and mindfulness techniques by training divers to be in a state of open monitoring associated with slow and ample ...breathing. Perceived stress is known to be diminished during meditation practice. This study evaluates the benefits of scuba diving on perceived stress and mindful functioning.
A recreational diving group (RDG;
= 37) was compared with a multisport control group (MCG;
= 30) on perceived stress, mood, well-being and mindfulness by answering auto-questionnaires before and after a 1-week long UCPA course. For the diving group, stability of the effects was evaluated 1 month later using similar auto-questionnaires.
Perceived stress did not decrease after the course for the MCG The divers showed a significant reduction on the perceived stress score (
< 0.05) with a sustainable effect (
= 0.01). An improvement in mood scale was observed in both groups. This was associated to an increase in mindfulness abilities.
The practice of a recreational sport improves the mood of subjects reporting the thymic benefits of a physical activity performed during a vacation period. The health benefits of recreational diving appear to be greater than the practice of other sports in reducing stress and improving well-being.
Meditative scuba diving improved overall PTSD symptoms after one month more than multisport activity but not significantly.
PTSD Intrusion symptoms were significantly improved after one month by the ...meditative diving.
The positive effects of meditative diving faded after 3 months.
Post-Traumatic Stress Disorder (PTSD) is a chronic and disabling disease that currently has no fully effective therapeutic solution. Complementary approaches, such as relaxation, sport, or meditation, could be therapeutic aids for symptom reduction. Scuba diving combines sport and mindfulness training and has been found to have a positive effect on chronic stress and PTSD.
The first objective of this pilot study is to compare the effectiveness of diving associated with mindfulness exercises (the Bathysmed® protocol) with multisport activity in reducing PTSD symptoms. The secondary objective is to compare the impact of the Bathysmed® protocol on mindfulness functioning in the two groups of subjects suffering from PTSD.
This proof-of-concept took the form of a controlled randomized clinical trial. The primary endpoint was the severity of PTSD symptoms, measured by the PCL-5 (PTSD Check List) scale. Half of the group were exposed to the Bathysmed® protocol (the experimental condition), and the other half to a non-specific multisport program.
Bathysmed® protocol improved PCL-5 scores more than the multisport program but the result was not significant. The protocol was significantly better than the multisport activity in reducing intrusion symptoms of PTSD after one month. Globally, trait mindfulness scores improved up to one month after the course, but the result was not significant. Three months after the course, there was no difference between the two groups with regard to PCL-5 and Freiburg Mindfulness Inventory scores..
Our study demonstrates the value of the Bathysmed® protocol even though it suffers from a lack of power and could only obtain partial but encouraging results. Mindfulness must be practiced over the long term to achieve stable benefits. This probably explains why no differences persisted three months after the course. Further work is needed to confirm the initial results obtained with this pilot study.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This study investigated the sources of physiological stress in diving by comparing SCUBA dives (stressors: hydrostatic pressure, cold, and hyperoxia), apneic dives (hydrostatic pressure, cold, ...physical activity, hypoxia), and dry static apnea (hypoxia only). We hypothesized that despite the hypoxia induces by a long static apnea, it would be less stressful than SCUBA dive or apneic dives since the latter combined high pressure, physical activity, and cold exposure. Blood samples were collected from 12SCUBA and 12 apnea divers before and after dives. On a different occasion, samples were collected from the apneic group before and after a maximal static dry apnea. We measured changes in levels of the stress hormones cortisol and copeptin in each situation. To identify localized effects of the stress, we measured levels of the cardiac injury markers troponin (cTnI) and brain natriuretic peptide (BNP), the muscular stress markers myoglobin and lactate), and the hypoxemia marker ischemia‐modified albumin (IMA). Copeptin, cortisol, and IMA levels increased for the apneic dive and the static dry apnea, whereas they decreased for the SCUBA dive. Troponin, BNP, and myoglobin levels increased for the apneic dive, but were unchanged for the SCUBA dive and the static dry apnea. We conclude that hypoxia induced by apnea is the dominant trigger for the release of stress hormones and cardiac injury markers, whereas cold or and hyperbaric exposures play a minor role. These results indicate that subjects should be screened carefully for pre‐existing cardiac diseases before undertaking significant apneic maneuvers.
This study investigated the sources of physiological stress in diving by comparing SCUBA dives, apneic dives, and dry static apnea. We conclude that hypoxia is the dominant trigger for the release of stress hormones and cardiac injury markers, whereas cold or and hyperbaric exposures play a minor role. These results indicate that subjects should be screened carefully for pre‐existing cardiac diseases before undertaking significant apneic maneuvers.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Introduction
Postmortem computed tomography can easily demonstrate gas collections after diving accidents. Thus, it is often used to support the diagnosis of air embolism secondary to barotrauma. ...However, many other phenomenons (putrefaction, resuscitation maneuvers, and postmortem tissue offgassing) can also cause postmortem gas effusions and lead to a wrong diagnosis of barotrauma.
Objectives
The aim of this study is to determine topography and time of onset of postmortem gas collections respectively due to putrefaction, resuscitation maneuvers, and tissue offgassing.
Materials and methods
A controlled experimental study was conducted on nine pigs. Three groups of three pigs were studied postmortem by CT from H0 to H24: one control group of nonresuscitated nondivers, one group of divers exposed premortem to an absolute maximal pressure of 5 b for 16 min followed by decompression procedures, and one group of nondivers resuscitated by manual ventilation and thoracic compression for 20 min. The study of intravascular gas was conducted using CT scan and correlated with the results of the autopsy.
Results
The CT scan reveals that, starting 3 h after death, a substantial amount of gas is observed in the venous and arterial systems in the group of divers. Arterial gas appears 24 h after death for the resuscitated group and is absent for the first 24 h for the control group. Concerning the putrefaction gas, this provokes intravenous and portal gas collections starting 6 h after death. Subcutaneous emphysema was observed in two of the three animals from the resuscitated group, corresponding to the thoracic compression areas.
Conclusion
In fatal scuba diving accidents, offgassing appears early (starting from the first hour after death) in the venous system then spreads to the arterial system after about 3 h. The presence of intra-arterial gas is therefore not specific to barotrauma. To affirm a death by barotrauma followed by a gas embolism, a postmortem scanner should be conducted very early. Subcutaneous emphysema should not be mistaken as diagnostic criteria of barotrauma because it can be caused by the resuscitation maneuvers.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, PRFLJ, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Ischaemia-modified albumin (IMA) is a marker of the release of reactive oxygen species (ROS) during hypoxaemia. In elite divers, breath-hold induces ROS production. Our aim was to evaluate the ...kinetics of IMA serum levels during apnea. Twenty breath-hold divers were instructed to perform a submaximal static breath-hold. Twenty non-diver subjects served as controls. Blood samples were collected at rest, every minute, at the end of breath-hold, and 10 min after recovery. The IMA level increased after 1 min of breath-hold (p < 0.003) and remained high until recovery. Divers were separated into 2 groups: subjects who held their breath for less than 4 min (G–4) and those who held it for more than 4 min (G+4). After 3 min of apnoea, the increase of IMA was higher in the G–4 group than in the G+4 group (p < 0.008). However, at the end of apnoea, the IMA level did not differ between groups. If IMA level was globally correlated with the apnoea duration, it is interesting to note that the higher IMA level was not found in the best divers. Similarly, if arterial blood oxygen saturation (SpO
2
) was globally inversely correlated with apnoea duration, the lowest SpO
2
at the end of breath-hold was not found in the divers that performed the best apnoea. We concluded that these divers save their oxygen. The IMA level provides a useful measure of resistance to hypoxaemia.
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DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Invasive infection caused by Saccharomyces cerevisiae is rare. We report the first case of osteomyelitis caused by S. cerevisiae (baker's yeast) in a post-traumatic patient. The clinical outcome was ...favorable after surgical debridement, prolonged antifungal treatment and hyperbaric oxygen therapy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Objective The glossopharyngeal insufflation maneuver (lung packing) is largely performed by competitive breath-hold divers to improve their performance, despite observational evidence of fainting and ...loss of consciousness in the first seconds of apnea. Methods We describe here the time course of hemodynamic changes, induced by breath-holding with and without lung packing, in 2 world-class apnea competitors. Results When compared with apnea performed after a deep breath (100% vital capacity), lung packing leads to a decrease in cardiac output, blood pressure, and cerebral blood flow during the first seconds after the beginning of apnea. The major hemodynamic disorders were observed in diver 1, who exhibited the greater increase in pulmonary volume after lung packing (+22% for diver 1 vs +10% for diver 2). After the initial drop in both cardiac output and blood pressure, the time course of hemodynamic alterations became quite similar between the two apneas. Conclusions Some recommendations, such as limiting the number of maneuvers and performing lung packing in the supine position, should be expressed to avoid injuries secondary to the use of glossopharyngeal insufflation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Drowning is still a major cause of accidental death worldwide. In 1997, Szpilman proposed a classification of drowning that has become the reference. As considerable efforts have been made to improve ...prevention and care, it seemed appropriate to reassess the prognosis and clinical presentation of drowning patients more than 20 years after this first publication. The aim of this study is to provide a reappraisal of patients who need advanced health care and a precise description of their respective neurologic, respiratory, and hemodynamic profiles.
This retrospective study was conducted over four consecutive summer periods between 2014 and 2017 in ICUs located in France, French Polynesia, and the French Antilles. Patients were classified according to the drowning classification system proposed by Szpilman.
During the study period, 312 drowning patients were admitted with severe clinical presentation (grades 2-6). All patients benefited from rapid extraction from the water (< 10 min for all) and specialized care (emergency medical services), starting from the prehospital period. Although the global hospital mortality was similar to that previously reported (18.5%), great differences existed among the severity grades. Respective grade mortalities were low for grades 2 through 5 (grade 2, 0%; grade 3, 3%; grade 4, 0%; grade 5, 2%), and the mortality for grade 6 remained similar to that previously reported (54%). These results confirmed that the occurrence of cardiac arrest after drowning is still bad prognosis. Conversely, for other grades, this study strengthens the importance of specialized intervention to interrupt the drowning process.
On the basis of these results, drowning-related cardiac arrest is still the prognosis cornerstone. For other victims, the prognosis was better than previously expected, which strengthens the importance of specialized intervention to interrupt the drowning process.
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