Common causes of open-circuit recreational diving fatalities

Diving fatalities causes were investigated in 947 recreational open-circuit scuba diving deaths from 1992-2003. Where possible, cases were classified at each step of a four step sequence: trigger, disabling agent, disabling injury, cause of death (COD). The most frequent adverse events within each step were: (a) triggers 41% insufficient gas, 20% entrapment, 15% equipment problems; (b) disabling agents--55% emergency ascent, 27% insufficient gas, 13% buoyancy trouble; (c) disabling injuries--33% asphyxia, 29% arterial gas embolism (AGE), 26% cardiac incidents; and (d) COD--70% drowning, 14% AGE, 13% cardiac incidents. We concluded that disabling injuries were more relevant than COD as drowning was often secondary to a disabling injury. Frequencies and/ or associations with risk factors were investigated for each disabling injury by logistic regression. (The reference group for each injury was all other injuries.) Frequencies and/or associations included: (a) asphyxia--40% entrapment (Odds Ratio, OR > or = 30), 32% insufficient gas (OR = 15.9), 17% buoyancy trouble, 15% equipment trouble (OR = 4.5), 11% rough water, drysuit (OR = 4.1), female gender (OR = 2.1); (b) AGE--96% emergency ascent (OR > or = 30), 63% insufficient gas, 17% equipment trouble, 9% entrapment; (c) cardiac incidents--cardiovascular disease (OR = 10.5), age > 40 (OR = 5.9). Minimizing the frequent adverse events would have the greatest impact on reducing diving deaths.