Why Divers Die: Part III

In the past two issues, we’ve highlighted cases from Diver Alert Network’s 2008 report on dive accidents and fatalities (it actually discusses dive incidents that occurred in 2006). In this final part, we’re also adding notes from a study DAN’s medical experts did on the same topic, published in the December issue of Diving and Hyperbaric Medicine. DAN researchers are interested in the effects of age on injury and death risk, because as people age healthier and stay active longer, those risks are inevitably higher. Reports from emergency-medicine departments indicate a substantial number of people injured in recreational sports are age 65 and older. They represent 17 percent of injuries in golf, 15 percent in tennis, 9 percent in fishing and 4 percent of diving injuries (although there’s no information on exposure duration).

For its study, DAN calculated the annual rates of dive-related deaths among DAN-insured divers between 2000 and 2006, and investigated the effects of age and sex on the death rates. Divers 60 and over had a relative risk four times greater than that of male teenagers. Young adult males had a four-fold greater risk than young adult females. However, the differences in risk associated with gender disappeared by age 60. Researchers think the youthful differences between the sexes reflect greater risk-taking due to men’s higher testosterone levels. However, the rates increased with age even when testosterone levels declined.

Matters of the Heart

In reviewing DAN’s cases and studies from the UK, Australia and New Zealand, we’re always taken by the number of divers who die from heart attacks. Their disease is often undiagnosed and their risk is increased by being overweight, out of shape, and either inexperienced or out of the water for a long time. The risk of dying during physical activity for older people is associated with a high prevalence of heart disease. People ages 66 to 74 are 27 times more likely to die from heart attacks than those ages 35 to 44. Responses to diving stress and exertion in people with heart disease, undiagnosed or not, may cause death or weakness, especially when the possibility of drowning is added to the mix.

Differences in fatality rates for men and women and their changes with age may be partially explained by the different prevalence of heart disease in the two sexes. Heart disease as an underlying risk in drowning is hard to determine when the baffling effects of drowning are included, so it can be underreported. On the other hand, in the absence of evidence, the diagnosis may be biased toward cardiovascular disease-related causes in older victims. When DAN diagnoses the disabling injury in each dive-related death for its annual report, it’s based on health history, accident scenario and autopsy findings.

Barry Hauser, 48, was an experienced diver with multiple medical problems, including severe coronary artery disease requiring a stent in his heart, obesity, high cholesterol, hypertension and chronic back pain. He and his wife were among a group of 20 divers aboard the Republic IV to dive for lobster at the Juno Ledge, two miles off Florida’s Juno Beach. Hauser made the dive 70 feet but became separated from his buddy and the group. He was discovered missing when the dive finished at 11 a.m., and crew found his body floating just north of the boat. Hauser had apparently inflated his BCD before losing consciousness. He was pronounced dead at the hospital, and his death was certified as drowning secondary to a heart attack.

Excluding cardiac causes, which were suspected in one-third of deaths in DAN’s insured divers over age 49, the fatality rate in older divers would still be greater than in younger divers, as the relative risks for embolism and drowning suggest. This may be related to a decline in physical ability - - muscle strength, flexibility, coordination and dexterity - - all of which may make older people prone to errors and more vulnerable.

Joan Radford, 66, was diving for lobster off Florida’s Big Pine Key. After entering the water, she had problems putting on her fins and mask while on the surface, possibly because she had significant degenerative joint disease. Radford dropped some of her lobster-gathering equipment, so her buddy descended to retrieve it. When he returned to the surface, Radford wasn’t there, so he assumed she had descended but he found her unconscious on the bottom. Radford was taken to the hospital, where she was pronounced dead from drowning.

Rough conditions on the water can also exacerbate health issues. This very experienced 64-year-old diver was making his third dive of the day with a buddy. They dived a wreck at 60 feet for 60 minutes before working their way up to 40 feet. The diver motioned to his buddy that he wanted to surface but they had trouble finding the chain that ran from the wreck to shore and surfaced in rough seas. The buddy went down briefly to 10 feet and when he resurfaced, the diver was unconscious. His buddy towed him to shore, where resuscitation efforts were unsuccessful. The only known issue on his medical history was prostate cancer but his autopsy revealed severe coronary artery disease, so he most likely had a heart attack before drowning.

Face Up To Your Health Issues

Preventing cardiac deaths during diving depends on divers’ knowledge of their health, an appreciation of specific dive risks and a willingness to adjust their behavior - - and lower their risk. In some of the fatal cases DAN studied, divers knew about their health risks but it’s unknown whether they sought medical opinion about their fitness to dive. A small fraction of divers who were unaware of pre-existing conditions could have benefited from regular medical exams. Then there are divers fully aware of their medical issues but keep diving without taking precautions.

One of them was Chester “Chet” Alan Robinson, 55. He was an experienced diver with a history of heart disease, including placement of a coronary artery stent, and had stopped taking his medications in February 2006 because he didn’t like how they made him feel. Robinson’s doctor had advised him not to dive, but Robinson went ahead with a dive that August to the Oriskany near Pensacola, FL. Robinson’s dive profile isn’t known but he did complete the dive with two buddies and was back on the charter dive boat at 1:30 p.m. While removing his dive gear, Robinson complained of chest pain and collapsed on the deck. The medical examiner said his death was caused by cardiac arrest.

Younger divers, don’t assume you’ve got a clean slate. If you have weight and heart issues, your mortality risk is higher than that of a decades-older diver who is physically fit. Consider this 40-year-old experienced but obese diver, who was part of a public service dive team performing a working dive in a river. He was wearing a wetsuit as he entered the water, tethered by a line, but the current was strong and visibility was poor. After two minutes at 12 feet, he surfaced in distress and lost consciousness. He was pulled back to the boat and team members performed CPR but he was pronounced dead at a medical center nearby. The autopsy disclosed severe coronary artery disease, and his death was ruled to be the result of a heart attack.

Gregory William Johnson, 43, had 45 dives but he was overweight and had poor physical conditioning. He and his brother arrived at the island of St. Maarten aboard the cruise ship Disney Magic and took a dive excursion with Dive Safaris. Johnson and his brother were on the bottom when he indicated he wanted to surface. He went up alone while his brother stayed on the bottom. When the brother surfaced a few minutes later, he found people trying to resuscitate Johnson, who had blood coming from his nose and was vomiting. The most likely cause of Johnson’s death is an air embolism from surfacing too quickly, although a heart attack can’t be ruled out.

Get a Medical Opinion

Some countries require divers to have mandatory annual physicals but in the U.S., it’s up to divers and their instructors to establish the need for physicals. While divers may be required to fill out a health-screening questionnaire by a dive training agency when they’re getting certified, most don’t get any medical opinion from their doctor about diving at all during their lifetime.

The American Heart Association (AHA) says screening for coronary artery disease risk factors, including family and personal history, should start at age 20. (Most questionnaires administered by dive training agencies fulfill this purpose.) DAN says divers over 35 might benefit from discussing their heart risk factors with their primary-care doctors. The AHA suggests medically supervised exercise stress tests in men over 40 and women over 55 who want to do competitive sports, have two or more coronary risk factors, and have one notably abnormal risk factor. A selective approach to medical evaluation of fitness for diving based on one’s individual risks seems most suited for recreational diving.

Stress and exertion are hazards you must consider when evaluating your health and fitness to dive. While there’s a broad consensus about the criteria for diving fitness, it’s essential that both the diver and his physician understand the risks.

The final decision to go diving is up to you. Sometimes personal choices go against medical advice but if you’re properly informed about your health risks, it’s less likely you’ll ignore them. For divers who stay physically fit, watch their health and choose their dives wisely, there is no age limit.

- - Ben Davison