Research and Outreach




A hyperbaric doctor examines tech diver Jeff Shirk using 3-D ultrasound. Earlier in the day Shirk experienced a serious case of acute immersion pulmonary edema during a dive.


"Your research saves lives, and your outreach efforts inform an entire community about safe diving practices," I recently wrote to DAN® research director Neal Pollock, Ph.D. I penned the letter after a long day in Newfoundland, Canada, that began with a stunning dive on a World War II shipwreck and ended with a friend taking an ambulance ride to the Health Sciences Center in St. John's.

DAN had been there for me before in the most classic sense. More than 15 years ago I was hit with a case of decompression illness (DCI) while exploring new cave passages in Mexico at a now famous site called The Pit. With assistance from DAN, I received a necessary hyperbaric chamber treatment and all the requisite follow-up care. But this time it was DAN's research and educational outreach that made the difference for my diving group. Both Pollock and hyperbaric medicine researcher Stefanie Martina had been filling my inbox with informative medical articles since we worked together on an expedition a few months earlier. In Pollock's words, "Data we gather on these projects is important, but our opportunity for outreach is priceless."

When my diving friend motioned for help beside our boat in Conception Bay, Newfoundland, the entire crew and our group of seasoned divers leapt into action. He was gasping for breath with a rattling gurgle, pulling at his neck seal, desperately trying to say, "I can't breathe!"

Within minutes, we had the victim, a very experienced technical diver, seated on deck and were removing his drysuit and dive gear. He coughed bloody froth into a bucket while we provided oxygen and supportive care.

Some might have guessed this was an embolism or "chokes," and others might have passed it off as an event of uncharacteristic panic, but knowing that this accomplished veteran had managed to suffer through 17 agonizing minutes of decompression and ascend at a normal rate led me to conclude that he was experiencing a little known malady I had recently read about and had witnessed before. His rapid improvement further corroborated my theory that he was experiencing immersion pulmonary edema (IPE).

IPE, which is abnormal leakage of fluid from the bloodstream into the alveoli during immersion, can occur in anyone immersed in water, even swimmers. The injured swimmer or diver develops a cough, has difficulty breathing, develops raspy breathing and often spits up frothy, blood-tinged liquid from the lungs. The symptoms may suddenly become acute when the person surfaces, because this represents the point of greatest ambient pressure differential between the mouth and the chest.

IPE has been reported in healthy, young individuals such as triathletes and combat swimmers as well as across the entire spectrum of the diving community, including people with reported heart and lung conditions. The onset may be very rapid or may develop over time and can even worsen over the course of daily, repeated immersion. During immersion, especially in cold water, blood is redistributed from the extremities to the lungs. When the victim is no longer in the water this edema gradually subsides.

When a diver or swimmer has difficulty breathing, they may panic, aspirate water and possibly drown. A diver may skip decompression obligations or ascend rapidly and experience additional barotrauma. For this reason, and because the symptoms can resolve rapidly once the diver is out of the water (often before reaching the dock or hospital), this phenomenon may be underreported and often misdiagnosed. Whether considered a panic attack or a result of ill-fitting or malfunctioning gear, cases of IPE may be completely overlooked. Despite the fact that our boat included safety officers, first responders, dive instructors and other experts, few of them had ever heard of IPE.

Studies have revealed that several external factors, including cold water, exercise and high work of breathing, may create the perfect IPE scenario. Numerous internal factors, such as hypertension, other cardiac issues, cardiovascular disease and excessive hydration, may also increase the likelihood of experiencing IPE. Some people seem to be susceptible to IPE; these people include, surprisingly, elite athletes as well as people with known cardiac and pulmonary issues.

IPE is diagnosed by exclusion (ruling out other possibilities), so it is vital that anyone experiencing symptoms seeks immediate medical attention. Other conditions that could cause similar symptoms, such as a heart attack or DCI, need to be considered first. Hyperbaric treatment is not needed for IPE, and symptoms generally resolve completely in 24-48 hours. Follow-up care involves medical assessment by a physician (one trained in dive medicine, if possible) who can rule out any other issues that need addressing and look for conditions that may contribute to future IPE susceptibility before recommending a return to diving.

I'm happy to report that within six hours of the emergency's onset, our victim transitioned from his dive accident to socializing with friends at the end of a long day. In between was an evacuation, an ambulance ride, an emergency room assessment, tests and a visit with a hyperbaric specialist. It was great to have a good ending to this very serious event, being in the company of good dive buddies, who all played an important role in our friend's rescue and treatment.

Another positive aspect of this experience was the realization that we were properly prepared to handle a diving emergency. The boat crew were well trained and equipped with oxygen and first-aid equipment. Rescuers stayed calm and levelheaded, as did the victim, who got himself safely to the surface without missing his decompression obligations or making a rapid ascent.

This incident highlights the importance of training, diving research and education. It is foolish, in my experienced opinion, to dive without DAN dive accident insurance; even if you never use it, you will be supporting important work that helps our community better understand and mitigate diving risks.
References
Moon RE, Martina SD, Peacher DF, et al. Swimming-induced pulmonary edema pathophysiology and risk reduction with sildenafil. Circulation 2016; 133(10):988-96. doi: 10.1161/circulationaha.115.019464.

Peacher DF, Martina SD, Otteni CE, et al. Immersion pulmonary edema and comorbidities: case series and updated review. Med Sci Sports Exerc. 2015; 47(6):1128-34. doi: 10.1249/mss.0000000000000524.

Wester TE, Cherry AD, Pollock NW, et al. Effects of head and body cooling on hemodynamics during immersed prone exercise at 1 ATA. J Appl Physiol 2009; 106:691–700. doi: 10.1152/japplphysiol.91237.2008
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© Alert Diver — Q4 Fall 2016