Why Divers Die: Part II

Last month, we dug into annual reports from Divers Alert Network (DAN) and the British Sub- Aqua Club that collect and publish dive accidents and fatalities. The basic factors for many of those: being lazy, being obese and succumbing to panic. In this article, we'll look at other reasons why divers die, including heading into running boat propellers, being unfamiliar with the dive gear, and a notthat- well-known health hazard that leads to a quick death by drowning.

Drowning While Having Plenty of Air

In the past, some divers have lost their lives underwater by drowning when they still had plenty of air available. It was a mystery until recently, but now the blame is placed on immersion pulmonary edema (IPE), which may be caused by hyperhydration. It happens when fluid leaks from the bloodstream into air sacs in the lungs, which can lead to heart failure or other cardiac problems.

According to Douglas Ebersole, a cardiologist in Lakeland, FL, and a technical dive instructor who consults for DAN, it is not depth-related, and it often occurs in healthy individuals. He says IPE can be difficult to diagnose and is most likely underreported because many other conditions present similarly, such as saltwater aspiration syndrome, pulmonary decompression sickness and respiratory infections. Symptoms include:

* breathing difficulties and confused actions like swimming in the wrong direction

* believing a regulator isn't working properly

* indicating you're out of air when you patently are not

* rejecting an alternate air source when you are truly out of air.

Chilly water and exertion increase the likelihood of an IPE occurring, so cold water dives can be the perfect place for that to happen. Take the Farne Islands off England's northeast coast, a favorite dive spot that is shallow but features very cold water. There were two 2017 cases of divers dying there in depths of less than 45 feet. In one case, the diver's body was found on the seabed, apparently after she had unsuccessfully tried to remove her gear. Another diver passed away at the surface after a 45-minute dive to 33 feet. His computer revealed he had made a three-minute safety stop at 18 feet. Both appeared to have plenty of air and drowned for no apparent reason.

But while IPE was originally thought to be a mechanism of being immersed in cold water, Ebersole says there have been multiple reports of it happening in warmer water, too. He cites the case of a 40-year-old woman diving in Grand Cayman, who aborted the dive after experiencing severe shortness of breath underwater. At the surface, she coughed up blood-tinged sputum. Although she was taken to the hospital, all symptoms resolved before she got there. Five years later, her symptoms reoccurred while diving the remote Cocos Island. Brought back aboard her liveaboard, she was given furosemide, a powerful diuretic, and bronchodilators, and her symptoms completely resolved within a few hours.

Divers who suffer from hypertension (high blood pressure) and smokers are most at risk for IPEs, says Ebersole. Factors that also increase the risk: wetsuits that fit too tightly, breathing high levels of oxygen (as with accelerated deco techniques), repetitive deep dives, missed decompression stops, and, interestingly, the consumption of fish oil.

To avoid IPE, Peter Wilmshurst, a cardiologist and dive medicine expert, recommends avoiding excessive hydration before a dive, which does run counter to prior advice we've written about being well-hydrated to counteract the potential for a DCI. In general, take the advice of staying well hydrated on a daily basis, but lower your IPE risk by not drinking excessive amounts of water before a dive.

Unfortunately, if you've suffered IPE once, there's a high chance you'll suffer again, says Ebersole. "Reoccurrence is common. If a casualty decides to continue diving, it's recommended he avoid diving in remote locations, and if he chooses to do so, to consider carrying diuretics and bronchodilators with him. Studies using vasodilators such as sildenafil (a.k.a. Viagra) to prevent IPE are underway, so many gentleman divers might have a better excuse for carrying them on dive trips!"

Beware of the Dive Boat

We reported in our April 2018 issue about a Chinese diver who surfaced at Apo Island in the Philippines without any type of surface marker and was struck and killed by another passing dive boat.

The DAN report tells of a 61-year-old diver who made an entry into rough water while the boat's propeller was still turning. He either hit his head on that or the rear platform, but regardless, he was knocked unconscious and fatally aspirated water.

When surfacing from a dive, here's a good reason why it's best to pop up well away from any boat: Last June, a British diver became unconscious and drowned after hitting his head on the underside of his support boat.

A Russian diver, attempting to board a dive boat in Egypt's Red Sea that was in the process of reversing away from the reef, didn't understand the warnings coming from the deck crew, and he was drawn onto the propellers with dreadful consequences -- his body was so mangled, the boat had to be towed back to shore before they could finally extract his remains.

Jacob Bury, an American in his 30s, living and working in Saudi Arabia as a youth-activities consultant, took a group of youngsters on their annual Red Sea dive trip last June. On the second day of their trip, Bury entered the water and got sucked into the dive boat's propeller. He was immediately given first aid, including a tourniquet to stem the bleeding, then rushed to a hospital in nearby Jeddah, but his right leg had to be amputated below the knee. (His students, friends and colleagues started a crowdfunding campaign to raise the $250,000 needed to equip Bury with a prosthetic limb).

Then there are the speeding boats that ignore or overlook dive flags. Last August, a 23-year-old diver was hit by a passing boat while surfacing off Hollywood Beach in Florida. His dive gear was ruined, but luckily, he survived his injuries. The culprit, a sports fisherman boat with a black bottom, is still at large.

Bad Sea and Weather Conditions

Weather and water conditions obviously have a crucial effect on whether or not it's safe to dive. So why can't dive staff crack down on divers, especially novice divers, when conditions look less than sublime? A 27-year-old diver with only 14 dives in his logbook rented dive gear while abroad and went with a group to an area known for strong currents. He used his air quickly, so the dive guide ascended with him, but later reported they had difficulty resisting a downcurrent. At nine feet deep, the guide signaled to him to grasp some kelp, but the victim let go and was last seen carried away by a strong undertow.

The risk of injury or death shoots up when a diver gets separated from the group. This is what happened to a 65-year-old diver who somehow got separated from a guided group of divers and surfaced alone in rough sea conditions. He was seen struggling to get to a tag line but sank before anyone on the boat could reach him. That's why it's wise to stick like glue to your buddy or guide in less-thanideal conditions in the water.

Get to Know Your Gear

Every report has cases of divers who went out with unfamiliar or improperly rigged equipment. A tragic example of this was provided by a 59-year-old male diver who, even though he had a number of different diving certifications, had not dived for a long time, but wanted to try out a new drysuit and new computer. Ascending with his buddy from a 130-foot bounce dive, with a brief stop at 65 feet, he started struggling with his equipment. At 20 feet, he was struggling with his mask. His buddy assumed he was out of air and gave him his own alternate, but the victim lost consciousness before they reached the surface and later died. It turned out his main regulator, long overdue for maintenance, was hard to breathe from at depth. His primary tank was empty, and his secondary supply, a pony tank, was mounted in such a way that its regulator's second stage would not reach the diver's mouth.

BSAC noted a significant number of incidents involving the use of surface marker buoys deployed from depth. That's because decompression-stop diving is more common in the U.K. and the buoy is deployed from deeper when the diver is doing a safety stop. But in these incidents, the diver often got entangled in the line and got dragged upward in an unscheduled and often rapid ascent.

Contaminated air is another thing to watch for -- faulty compressors in dive shops or on liveaboards are unfortunately not that rare. Look at the compressor's air intake to ensure it's not near any source of carbon monoxide, like the boat engine's exhaust. A rudimentary inspection of the tank you're supplied can alert you to possible problems (and any dive operation should have a portable analyzer available), but you usually have to trust that the tanks supplied are in good shape. A British diver on a dive resort vacation last September found that his recently serviced regulator became gradually more difficult to breathe from. When he returned home, a service technician found it was blocked with aluminum powder, presumably from improperly serviced tanks. He tried to contact the dive center to warn them of the problem, but never got a reply.

A bigger problem than bad gear? A diver's bad response to the situation. In their book Scuba Diving Safety, Dan Orr and Eric Douglas quoted Dr. George Harpur, medical director of the Tobermory Hyperbaric Facility in Ontario, Canada, as saying, "We are not able to document a single case in which equipment failure directly caused a diver's death or injury. It has been the diver's response to the problem that results in the pathology."

Good News and Bad News

Some good news, at least from the BSAC report: DCI incidents are declining. That's probably due to the efficiency of diver rescue techniques, including controlled buoyant lifts and air sharing.

Unfortunately, BSAC's analysis of resuscitation techniques indicates recovery rates of less than 10 percent. CPR can be significantly enhanced aboard a dive boat if an automatic external defibrillator is on hand.

The BSAC report details a litany of "near-miss" dive incidents without apparent medical consequences. And while the number of fatal incidents reported has plateaued over the last four to five years, the 19 reported in the UK last year is higher than the average for the previous 10 years.

So our advice, as it was from past "Why Divers Die" articles, stays pretty much the same: Know your dive experience and boundaries; stay vigilant with your weight, health and medical conditions; get familiar with the gear you're using; don't dive in conditions you can't handle, and keep an eye on your dive buddy, your air, your computer and that boat propeller.

-- Ben Davison