Diving practices in technical divers' community and behaviour towards self-reported unusual symptoms

Area of Science:

• Diving Medicine
• Hyperbaric Physiology
• Epidemiology

Background:

• Deep recreational diving increasingly utilizes helium-based gas mixtures (trimix).
• The practices and risks associated with trimix diving are not well-documented.
• Technical diving communities face complex logistical and decision-making challenges.

Purpose of the Study:

• To conduct an epidemiological inventory of practices and diving-related incidents in the technical diving community.
• To document the characteristics and inherent risks of deep recreational diving with helium-based gas mixtures.
• To assess self-reported symptoms, treatments, and outcomes following trimix dives.

Main Methods:

• An international online survey was distributed via social networks to certified trimix divers.
• Data collected included demographics, diving experience, dive management, and self-reported incidents.
• 558 questionnaires were analyzed, focusing on practices and medical outcomes.

Main Results:

• The study population consisted mainly of experienced male divers over 46 years old, with prevalent rebreather use.
• Many divers exceeded recommended gas density limits, and 10% reported symptoms of gas toxicity (primarily nitrogen narcosis).
• 36% reported diving incidents, with a significant proportion experiencing decompression sickness (DCS) or breathing issues; treatment was often neglected.

Conclusions:

• The diversity in trimix diving practices underscores a lack of supporting scientific data.
• The accident rate in mixed-gas diving may exceed that of air diving, though often of mild severity.
• Despite high knowledge levels, treatment for diving incidents is frequently overlooked, necessitating further research and education.