DIVE ACCIDENTS: ALL CONCERNED

The summer season ends for most of you. And like every year, a number of accidents have enamelled the summer months. We asked Mathieu Coulange, from the department of Hyperbaric Medicine at Sainte-Marguerite Hospital in Marseille, to help us better understand what leads to the accident, and what are the essential actions when the emergency occurs.

ABOUT 350 ACCIDENTS PER YEAR IN FRANCE

"There are 1 accidents worldwide for 6 10 000 each year, which represents approximately 350 accidents per year processed in French hyperbaric centers. The majority occur on the Mediterranean coast mainly in the summer, with a recrudescence of accidents in winter, due to an increase in the number of practitioners during this period. A recent epidemiological study conducted on more than 500 diving accidents treated at the Marseille Public Assistance Hospital shows that the casualty is most often a leisure diver (85%), older (40 years on average) than the population. divers affiliated to the French Federation of Study and Sports underwater (FFESSM). Seventy-five percent are male, which corresponds to the normal distribution in the recreation divers population, 10% have already had a diving accident. All levels are concerned including the supervisors who represent 1 / 5ème of the casualties. Twenty percent occur during training. The incidence increases with depth. Nevertheless, more than a third of the accidents occur within 30 meters of depth. The most frequent accident is the desaturation accident (53%) followed by severe barotrauma (15%) and the cardio- Vascular Immersion (5%). "

STABLE FIGURES

Since the beginning of the year, the Hyperbaric Center of Sainte Marguerite, which manages the area between Martigues and La Ciotat, has received 62 patients, two of whom have died. This is of course too much, but the first observation is nevertheless encouraging: the number of accidents has remained stable for several years, despite an increase in the number of practitioners, and an aging population of divers. Secondly, the accident rarely concerns unconscious divers who do not respect the procedures. The reality is more subtle.

ADAPT DIVES TO DIVERS

Mathieu Coulange's message is clear: "it is not the person who has to adapt to diving, but the diving that must be adapted to everyone". One can dive even if one is rather sedentary, even old, but favoring the first 20 meters, in good conditions. And from 45-50 years, it is better to ask his doctor to make us undergo a stress test. Conversely, even younger, sporty and apparently healthy, you have to be careful: do not dive deep when you take back after several months, do not multiply the successive deep, not be in deficit of hydration ....

THE HOUSINGS ARE FULL OF "SERIOUS" DIVERS

These are rarely serious errors that lead to the box, but rather the fact that people do not listen enough to their impressions. A posteriori, many casualties recognize that they "felt bad, this dive ..." Tired, not comfortable, often anxious not to penalize other members of the group by decreasing for example the expected depth. We are far from the image of the burnt head that ends at the caisson. Reluctantly, they go anyway, and that's where the accident happens. Not because we made a mistake: "Moreover, says the doctor, now that we have access to all the information from diving with computers, we can see that divers do not lie and do not look to minimize their diving profile. "

TAKING INTO ACCOUNT THE GLOBALITY OF ITS ACTIVITY

"The problems of desaturation, for example, explains Mathieu Coulange, it is 50% of the cases that we have to deal with. And most often, if we apply the procedures, if we do not delay, the diver recovers perfectly. But again, it is the global environment and not this unique dive that will have consequences. If in the days before the diver pulled on the rope, multiplied for example the successive ones, the recovery will be much more complicated. "That's often the problem. To respect what is written on the computer is not always enough, it is necessary to take into account the totality of its activity.

PRIVILEGED "COMFORTABLE" CONDITIONS

Lungs and inner ear are the main victims of barotrauma, which accounts for about 20% of accidents. Luckily, severe lung pressure surges are rare, but they can be tragic. This also poses, according to Mathieu Coulange, the question of the risk benefit ratio of certain practices: “70% of pulmonary overpressures, he explains, occur in training; one can then ask the question whether it is necessary to keep certain exercises, such as CSR… ”Finally, what is called immersion pulmonary edema, sometimes confused with pulmonary overpressure, can also be an accident. serious. This is a phenomenon of cardiac decompensation, which has the effect of releasing fluid in the alveoli. The lung gradually drowns. And here again, favoring simple conditions of practice, while reducing as much as possible the effort, the cold, the discomfort, constitutes an accident prevention, particularly in a sedentary.

REMOVE THE SAME INCIDENT

10 15% of treated patients had, during the dive, a problem to manage: shortness of breath at the bottom, air supply problem, cramp ... "At the slightest incident, it is necessary to interrupt the dive, or in any case bring it back to something more reassuring, go back for example in the zone 20 meters if one were deeper. To do it, to act as if nothing had happened, is often to risk the accident. Special attention must also be paid to air management: drownings on air failure remain a cause of death.

DO NOT HAVE FEAR OF ALERTING

And if the incident occurs, the practitioner insists: "It is important not to be afraid to alert for nothing, I prefer it to a late charge. This is very rarely the case, he continues, and even a minor incident must be addressed. The speed of reaction is important: the sooner we arrive at the caisson, the more short and effective the treatment will be. Any unusual tiredness, any persistent abnormal signs must prompt to alert the CROSS. Who will get in touch with a hyperbaric service, and tell you what to do. "I also fully trust the instructors, insists Mathieu, who know how to react when one of their customers shows worrying signs. But it is for them that they still have to evolve: one accident in five concerns a supervisor, and they often hesitate, they minimize, for fear of having to interrupt their season. But we are well aware that they have obligations, and our goal is always to let them return to the water as soon as possible. "

THE QUALITY OF THE ALERT MESSAGE

The quality of the warning message, and the first information transmitted to health professionals, is also essential. The sport code provides for the use of a card that includes a number of elements to be informed. "But it still remains, explains Mathieu Coulange, in panic, little used": barely 10% of files contain the famous diver evacuation form. The "characteristic of the dive" part is correctly filled (100%) outside the items relating to the ascent rates. The "observed signs" and "first aid" parts are also systematically filled with relevant data, but the "medical intervention" part is never completed. "This sheet could be optimized by replacing the" medical intervention "part with an" alert message "part that is almost identical to the alert form of the Regional Operational Monitoring and Rescue Center (CROSS) in order to facilitate the procedure. . "
Below, an example of the evolution of the alert form, proposed by the Mediterranean Medical Society of Maritime Emergency ...

HYDRATION AND OXYGEN

It is already a reality when everything goes well, but hydration becomes essential as soon as there is suspicion of accident. "In general, explains Mathieu, it is advisable to compensate each hour of diving with rehydration with at least half a liter of water." In case of problems, this is one of the first things to do: make the person drink abundantly. And put it under oxygen almost immediately. "This raises the problem of individual divers," says Matthew, who believes that access to medical oxygen can be complicated. In degraded mode, I prefer that they then use oxygen diving rather than nothing at all. From these first two gestures often depends the quality of the recovery. Then, whether you call the CROSS at sea or call the UAS because you are down, both of you will immediately contact a specialist who will be able to guide you.

NEW ACCIDENTS

If the number of accidents is stable, Mathieu Coulange sees arriving at the caisson of new profiles: seasoned divers, who decided for example to use Nitrox, or to dive into a rebreather. But who, instead of using them to do the same dives as before by increasing their safety, will use them to "push" their explorations. Without necessarily having all the necessary experience and having been sufficiently trained. In summary, once again, common sense and humility can help minimize the risks. Without canceling them. But at the slightest doubt, speak! Do not let a dive incident turn into a disaster because you will not want to "piss off the world": the teams of hyperbaric centers are there neither to judge you nor to punish you. And most often, they are divers, like you!

MATHIEU COULANGE

Mathieu Coulange works in the Hyperbaric Medicine Service of Marseille Hospitals, he is a graduate in emergency medicine and sports medicine, doctor of science in “integrated physiology in extreme conditions”, member of the board of the Société de Physiologie et de Underwater and Hyperbaric Medicine in French Language, co-founder of the Mediterranean Medical Society for Maritime Emergency, expert at the Aix en Provence Court of Appeal, operational firefighter diver and captain doctor at the National Civil Security Diving Center. He participates in the training and retraining of divers and diving doctors, and medicalises survival courses. He is co-author of the book “Secure your diving” and associate coordinator of the “physiology and medicine of diving” treatise with Ellipses editions.