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Immersion pulmonary edema (IPE) is a misdiagnosed environmental illness caused by water immersion, cold, and exertion. IPE occurs typically during SCUBA diving, snorkeling, and swimming. IPE is sometimes associated with myocardial injury and/or loss of consciousness in water, which may be fatal. IPE is thought to involve hemodynamic and cardiovascular disturbances, but its pathophysiology remains largely unclear, which makes IPE prevention difficult. This observational study aimed to document IPE pathogenesis and improve diagnostic reliability, including distinguishing in some conditions IPE from decompression sickness (DCS), another diving-related disorder.Thirty-one patients (19 IPE, 12 DCS) treated at the Hyperbaric Medicine Department (Ste-Anne hospital, Toulon, France; July 2013-June 2014) were recruited into the study. Ten healthy divers were recruited as controls. We tested: (i) copeptin, a surrogate marker for antidiuretic hormone and a stress marker; (ii) ischemia-modified albumin, an ischemia/hypoxia marker; (iii) brain-natriuretic peptide (BNP), a marker of heart failure, and (iv) ultrasensitive-cardiac troponin-I (cTnI), a marker of myocardial ischemia.We found that copeptin and cardiac biomarkers were higher in IPE versus DCS and controls: (i) copeptin: 68% of IPE patients had a high level versus 25% of DCS patients (P < 0.05) (mean ± standard-deviation: IPE: 53 ± 61 pmol/L; DCS: 15 ± 17; controls: 6 ± 3; IPE versus DCS or controls: P < 0.05); (ii) ischemia-modified albumin: 68% of IPE patients had a high level versus 16% of DCS patients (P < 0.05) (IPE: 123 ± 25 arbitrary-units; DCS: 84 ± 25; controls: 94 ± 7; IPE versus DCS or controls: P < 0.05); (iii) BNP: 53% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 383 ± 394 ng/L; DCS: 37 ± 28; controls: 19 ± 15; IPE versus DCS or controls: P < 0.01); (iv) cTnI: 63% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 0.66 ± 1.50 μg/L; DCS: 0.0061 ± 0.0040; controls: 0.0090 ± 0.01; IPE versus DCS or controls: P < 0.01). The combined "BNP-cTnI" levels provided most discrimination: all IPE patients, but none of the DCS patients, had elevated levels of either/both of these markers.We propose that antidiuretic hormone acts together with a myocardial ischemic process to promote IPE. Thus, monitoring of antidiuretic hormone and cardiac biomarkers can help to make a quick and reliable diagnosis of IPE.

OBJECTIVE. The purpose of our study was to define the postmortem CT semiology of gas collections linked to putrefaction, postmortem "off-gassing," and decompression illness after fatal diving accidents and to establish postmortem CT diagnostic criteria to distinguish the different causes of death in diving. SUBJECTS AND METHODS. A 4-year prospective study was conducted including cases of death during diving. A hyperbaric physician analyzed the circumstances of death and the dive profile, and an autopsy was performed. Subjects were divided into three groups according to the analysis from their dive profile: decompression illness, death after decompression dive without decompression illness, and death after nondecompression dive without decompression illness. Full-body postmortem CT was performed before autopsy. RESULTS. The presence of intraarterial gas associated with death by decompression illness had a negative predictive value (NPV) of 100%, but the positive predictive value (PPV) was only 54% because of postmortem off-gassing. The PPV reached 70% when considering pneumatization of the supraaortic trunks. Pneumothorax, subcutaneous emphysema, and intraarterial gas, all of which are classic criteria for decompression illness diagnosis, are not specific for decompression illness. CONCLUSION. This study is the first to show that pneumothorax, subcutaneous emphysema, and intraarterial gas, all of which are classic criteria for decompression illness diagnosis, are not specific for decompression illness. Complete pneumatization of supraaortic trunks is the best postmortem CT criteria to detect a fatal decompression illness when CT is performed within 24 hours after death.

Background: This study aims to determine the potential risk factors associated with the development of severe diving-related spinal cord decompression sickness (DCS)., Methods: Two hundred and seventy nine injured recreational divers (42 ± 12 years; 53 women) presenting symptoms of spinal cord DCS were retrospectively included from seven hyperbaric centers in France and Belgium. Diving information, symptom latency after surfacing, time interval between symptom onset and hyperbaric treatment were studied. The initial severity of spinal cord DCS was rated with the Boussuges severity score, and the presence of sequelae was evaluated at 1 month. Initial recompression treatment at 2.8 ATA with 100% oxygen breathing or deeper recompression up to 4 or 6 ATA with nitrogen or helium-oxygen breathing mixture were also recorded., Results: Twenty six percent of DCS had incomplete resolution after 1 month. Multivariate analysis revealed several independent factors associated with a bad recovery: age ≥ 42 [OR 1.04 (1-1.07)], depth ≥ 39 m [OR 1.04 (1-1.07)], bladder dysfunction [OR 3.8 (1.3-11.15)], persistence or worsening of clinical symptoms before recompression [OR 2.07 (1.23-3.48)], and a Boussuges severity score >7 [OR 1.16 (1.03-1.31)]. However, the time to recompression and the choice of initial hyperbaric procedure did not significantly influence recovery after statistical adjustment., Conclusions: Clinical symptoms of spinal cord DCS and their initial course before admission to the hyperbaric center should be considered as major prognostic factors in recovery. A new severity score is proposed to optimize the initial clinical evaluation for spinal cord DCS.

Objective: We have performed a survey on the use of aspirin in decompression sickness (DCS) treatment in French hyperbaric centers'. We also conducted a review of literature to determine if aspirin was beneficial to treat human victims of DCS., Methods: Prospective observational study investigating French hyperbaric centers' prescription of aspirin to DCS' divers victims. The question we asked by mail or phone to French hyperbaric centers was: Do you give some aspirin to a diver with DCS if this treatment has not been given yet (on the site of accident)., Results: A large majority of French hyperbaric centers (77.5%) consider aspirin in DCS treatment. However this practice is not consensual. There is no evidence from the literature to support the efficiency of aspirin in DCS., Conclusions: Although aspirin is widely used for DCS treatment in France, more research is needed to determine if aspirin is useful.

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 phenomena (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. 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. [ABSTRACT FROM AUTHOR]

Summary: Scuba diving is increasingly popular for children. However, this activity, including in shallow water, can be responsible for severe accidents. We report the case of a 13-year-old boy who dove for the first time in the Mediterranean Sea and suffered pulmonary barotraumas, complicated by arterial gas embolism with pneumomediastinum, cerebral, and coronary injuries. Any symptoms occurring after a dive, even in shallow water, must be considered a diving accident. Emergency medical personnel should contact a hyperbaric center for advice. In case of coronary or cerebral gaseous embolism, specific management requiring therapeutic recompression is urgently required. [ABSTRACT FROM AUTHOR]