Why Divers Die: Part I

Every year, several hundred divers die around the world. Their deaths are usually caused by bad decisions, like diving beyond one's experience, diving with known medical conditions and diving in bad conditions. Most dive-related deaths are avoidable, and many of them might have had better outcomes through better training, better knowledge of the associated risks, appropriate medical screening, better gear maintenance -- and just plain common sense.

Since our founding in 1975, we have published significant dive fatality cases so that our readers might better prepare themselves for safe diving. For many years, we relied on Divers Alert Network (DAN) and the cases it gathered of U.S. fatalities, but DAN no longer compiles them for public attribution. This year, we're using cases studied by DAN's Asia-Pacific division. We hope that by explaining these cases, divers will understand better how they could contribute to their own demise, and exercise proper judgment throughout their diving career.

What Would Your Doctor Say?

For years, we've been reporting on the dilemma of divers reporting medical conditions. There are some who solicit letters from their doctors indicating they are fit to dive and get themselves cleared before they arrive at their destinations. There are those divers with conditions well managed by medications who fear they will be denied diving by naïve dive operators if they disclose those conditions. And there are those who carry their doctor's permission letters, disclose their conditions, and are still ordered to get a local doctor certificate. Disclosure is a dilemma for some divers, but the upshot is that diving is stressful and conditions can overwhelm a diseased heart. Even in snorkelers, as this first case indicates.

This 64-year-old woman visiting the Great Barrier Reef (GBR) was morbidly obese, a poor swimmer and taking a mix of medications -- anti-arrhythmics, anti-convulsants and anti-depressants -- but she didn't declare any health issues on the dive shop's form. She went snorkeling alone and five minutes later, crew members saw her motionless and unconscious, 13 feet from the stern; no one had heard any splashing or call for help. She was pulled on board, unconscious, not breathing and with no palpable pulse. CPR was unsuccessful. Had she declared her medical conditions and lack of swimming skills, it's likely the dive operator would have advised her against snorkeling -- or even prevented her from snorkeling, especially when doing it solo -- but we know many divers keep adverse health conditions under wraps for fear of being prevented from going in the water.

Then there are those people who don't want to know what's going on with their bodies, avoid doctors and just go diving. Take this 53-year-old, who had logged 2,000 dives and sure looked fit and healthy. But he had a strong family history of heart disease and told others he "avoided doctors." He took a day trip on a dive boat with 13 passengers; he didn't declare any medical conditions prior to diving. He was paired with an inexperienced buddy and they made an uneventful 40-minute drift dive down to 54 feet. The second dive was a wreck dive to 80 feet, but after 40 minutes, the buddy was low on air and wanted to surface. They did not do a safety stop and inadvertently ascended the anchor line of another boat. The man decided he and the buddy should swim to their own boat, about 300 feet away. However, his buddy was unable to swim against the current, so the man towed him for several minutes -- that's a lot of work -- until the buddy was able to make headway. When they reached their boat's line, they pulled themselves along it, but when the buddy reached the boat, he noticed the man was floating away, face-down and motionless. Unconscious, with his mask in place and regulator in his mouth, he was dragged aboard the boat and CPR commenced, but it was unsuccessful. He died of an arterial gas embolism, but coronary atherosclerosis was a significant contributor. DAN reports that "in a diver dying of a cardiac arrhythmia due to heart disease, normal off-gassing of nitrogen via the lungs can be compromised."

So, need we lecture? Avoiding doctors does not make one a manly diver. Accept your age gracefully, as well as your medical conditions. Older divers, especially those with a known significant medical condition and/or relevant family history, like the dead diver above, need to check in with their doctor for an all-clear before a dive.

Back to snorkeling. Finning long distances, through ocean chop or against tough currents, can be hard work, as any diver knows. But what about all of that pre-dive exercise?

This 56-year-old man was visiting the Great Barrier Reef (GBR) on a day trip charter boat. He was an inexperienced snorkeler, but he was in good shape -- so he thought -- and had snorkeled for 30 minutes, played beach cricket and then hiked up a hill. An hour after lunch, he went snorkeling, and 15 minutes later, a crew member on lookout noticed him drifting past, staring at those on board. The lookout shouted, "Are you OK?" and the man raised his arm weakly and appeared to wave goodbye to his wife. The lookout reached him just as he began to sink, rolled him over and found him to be unconscious. He gave two rescue breaths and towed the man to the boat, then started CPR for 10 minutes as the boat motored to a nearby resort. On arrival, a guest and the boat skipper continued CPR, but stopped after no response. It's surmised that he died from an irregular heartbeat due to too much exertion.

Don't Panic -- And Make Sure Your New Mask Fits

Panic is a serious stressor that can lead to cardiac arrest, as happened to this 61-year-old woman on a GBR day boat trip with 88 passengers. She joined a group that snorkeled from a beach fringed by a coral reef that began 65 feet from shore. Accompanied by another passenger, who was using a "noodle" buoyancy aid, she snorkeled toward the tender. However, when she encountered a strong current, reported to be around five knots, she began to panic. Her buddy shared his noodle with her, and then the boat towed them to chest-deep water. The woman became unconscious soon after walking to shore. Her husband, finding no pulse, started CPR, but it was unsuccessful. Again, cardiac arrest was the probable culprit, due to panic and exertion against a strong current.

In our lead story about CoCoView, we talk about required checkout dives. A lot of experienced divers like to avoid them, especially if it means missing a boat dive or if the dives are staged at an uninteresting site. But if one has been out of the water for a while or has new gear, a checkout is essential. Now in this case, a 52-year-old did a checkout dive, but didn't act on what he learned. He had just bought a new mask and snorkel, which he used the day before his fatal dive, but he complained that he couldn't get a good mask seal; the mask didn't flood, it just leaked enough to be annoying. Diving with two friends, one an inexperienced diver, he appeared relaxed underwater , but twice his buddy saw him kneeling on the seabed, clearing his mask, the last occasion being 20 minutes into the dive. After the man returned his 'OK' signal, the buddy swam off to continue diving. But after a few minutes, the buddy could not see the diver and did a search before returning to the boat alone. On the way, he found the man's mask and snorkel, but the man was neither on the surface nor in the boat. The two other divers radioed for assistance, and a nearby vessel found him floating face-down on the surface, approximately 650 feet from the dive boat. He was unconscious, regulator out of his mouth, and not wearing his weight belt. CPR was unsuccessful.

Of course, had the two divers stuck together, the deceased might still be alive. More about buddy diving next time.

-- Ben Davison