Every summer, on the busy beaches of Charente-Maritime, swimmers suffering from sudden coughs and shortness of breath worry the emergency services even though they have not drunk a single sip of water. To remove doubt about this mysterious respiratory distress that is often put, a little hastily, in the “dry drowning” box, a vast medical study began on August 15, 2026 and will continue until July 15, 2027 across the entire coastline.
This pathology, called immersion pulmonary edema (OPI), is the subject of a study carried out by intern Antonin Mayet, Dr Lorraine Marchal and Dr Martin Cardeillac at Littoral Atlantique hospital group from La Rochelle. Rare, it concerns 1 to 2% of those practicing nautical activities, but also affects young and athletic people “in excellent apparent health”. Objective: better recognize it, clarify “dry drowning” and make swimming safer.
Understanding OPI: edema without “swallowing the cup”
L’OPI corresponds to an accumulation of fluid in the lungs which occurs during or after immersion, without it being necessary to have inhaled water. THE Littoral Atlantique hospital group describes a particular mechanism: “This phenomenon is explained by a complex physiopathological mechanism, linked in particular to the effects of immersion on blood circulation and the heart.“, he explains. This definition already allows us to separate OPI from a simple episode where we really swallowed water.
In the field, the symptoms of OPI can be surprising. Sudden shortness of breath, cough, feeling of tightness or significant breathing difficulties sometimes give the impression of acute heart failure in people with no previous history. “Contrary to popular belief, it is possible to present severe respiratory signs, or even symptoms close to heart failure, without having ‘swallowed the cup’“, explains the Littoral Atlantique Hospital Group, while the study recalls that these worrying pictures also occur in young and athletic people.
Charente-Maritime, life-size laboratory for the OPI
Since August 15, the study has been monitoring all cases suggestive of OPI recorded on the coast of Charente-Maritimefrom simple discomfort to vital distress, until July 15, 2027.If OPI remains rare (1 to 2% of those practicing nautical activities), it can be potentially serious and requires specific and rapid treatment.“, insists the Littoral Atlantique Hospital Group, which wants to precisely document the circumstances, symptoms and care pathway of each episode.
The system is based on “rare collective mobilization”, according to the Littoral Atlantique Hospital Group: the SAMU – Center 15the firefighters of SDIS 17aquatic rescuers, private ambulance drivers, organizers of triathlons or swimruns and all of the department’s hospitals report suspected cases. In a region where bathing, surfing, diving or swimming attract many vacationers, Charente-Maritime becomes an ideal study area to understand how this pathology emerges in a real situation.
A study to turn the page on “dry drowning”
The study also wants to correct the vocabulary. “This reality also helps clarify a widespread idea: ‘dry drowning’, as it is often understood, does not really exist. In many cases described this way, it could in fact be OPI“, explain the doctors behind the project.
The researchers hope, by listing the episodes and refining the clinical description, to better recognize OPI in the field and to better inform those practicing major nautical activities who agree to participate in this long-term investigation.