Cardiovascular risk assessment in divers: Toward safer diving

Area of Science:

• Cardiovascular physiology
• Diving medicine
• Risk assessment

Background:

• Diving environments pose risks of acute incapacitation, potentially leading to fatal outcomes.
• Unlike aviation's "1% rule" for pilot fitness, diving lacks formal cardiovascular risk limits.
• Cardiovascular events in divers can result in fatal accidents, necessitating risk assessment.

Purpose of the Study:

• To propose a cardiovascular risk management system for divers, analogous to aviation safety standards.
• To establish a formal limit for cardiovascular risk in divers to prevent fatal incidents.
• To identify specific age groups that would benefit most from updated dive medical guidelines.

Main Methods:

• Utilized the modified Canadian Cardiovascular Society (CCS) Risk of Harm (RH) formula to calculate cardiovascular risk in divers.
• Calculated maximum acceptable sudden cardiac incapacitation (SCI) rates based on CCS criteria and average diving frequency.
• Analyzed the age-dependency of cardiovascular risk and its implications for dive fitness.

Main Results:

• The modified CCS formula allows calculation of cardiovascular fatality rates per year for divers.
• An acceptable SCI limit of 2% per year was derived, aligning with current dive medical examination practices.
• Older divers (≥ 50 years) with untreated cardiovascular risk factors stand to benefit significantly from this proposed limit.

Conclusions:

• A cardiovascular risk limit, termed "unfit to dive" if SCI exceeds 2%/year, is proposed for divers.
• This system is particularly relevant for older divers where cardiovascular risk factors are prevalent.
• Implementing a cardiovascular risk management system can reduce fatal diving accidents, especially in older recreational and professional divers.