Spring is here - and with it comes the start of the new diving season.

An ideal time to get a medical check-up for diving. A Dutch study shows just how crucial health risk factors can be in connection with diving incidents.

Walensee. Imagetemplate: Renaud Jourdan.

Over a period of 57 (!) years - from 1966 to 2023 - a total of 228 diving accidents that were treated at the Diving Medical Center of the Dutch Navy were evaluated. Remarkably, only seven ended fatally. This underlines one thing above all - even if not all accidents in the Netherlands were recorded, this small number shows how safe diving is - or could be - in principle.

The researchers analyzed the incidents using a so-called “chain of events analysis” in order to better categorize and understand the triggering and facilitating factors. The most important results at a glance:

• Predisposing factors

In over 90% of cases, at least one such factor was identified - most frequently health problems (58%), followed by activity, planning and education. In more than two-thirds of cases, pre-existing medical problems contributed to the occurrence of an incident.

• Triggers

In just about half of the cases, a clear triggering moment could be identified - i.e. the first recognizable incident that turned a previously normal dive into an emergency. Frequent triggers were physical overexertion, a primary diving error or technical problems with the equipment.

• Disabling Agent

This term describes an action or circumstance that led directly to injury or, for example, decompression sickness. By far the most common was an ascent that was too fast.

• Disabilities (consequences of accidents)

Decompression sickness was diagnosed in more than 60% of cases, followed by a few but severe gas embolisms - these were responsible for almost half of all deaths (3 out of 7). Other diagnoses such as pneumothorax or immersion pulmonary edema were rare.

Discussion

It is surprising that no cardiovascular events were identified as a direct cause of accidents in this study. Yet other studies see these as the most common medical cause of diving incidents. This is probably due to the categorization: in this study, such events were grouped together under predisposing factors. In addition, the group of divers studied was relatively young (average age: 34 years).

Once again, it becomes clear how big a role pre-existing health problems play in diving accidents. It is also striking that physical exertion was the most frequently cited triggering factor - followed by diving errors, equipment problems and anxiety reactions. These often led to loss of control, rapid ascent and ultimately to decompression sickness or air embolisms.

Conclusion

Health, solid diving training and reliable equipment are the three most important pillars of diving safety.

The Swiss Society for Underwater and Hyperbaric Medicine (SUHMS) recommends regular diving medical examinations: every two years between the ages of 18 and 40, and annually from the age of 40.

This retrospective study clearly shows how useful these recommendations are. So take advantage of the start of the season and have another diving medical consultation. You can find swiss diving doctors here.