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by Michael Menduno
May 1, 2019—Nearly three dozen rebreather aficionados made the biannual trek to Ponza, Italy, a picturesque island in the Tyrrhenian Sea about a three-hour journey from Rome. They were there for the sixth International Rebreather Meeting organized by Andrea Donati, owner of Ponza Diving Center, and his partner Daniela Spaziani. The goal of the four-day meeting, which was sponsored by a number of manufacturers and organizations, including JJ CCR, Shearwater, DAN Europe, Società Italiana Medicina Subacquea e Iperbarica (SIMI), and the Italian rebreather users’ association CCR Italia, was to provide the latest research and information to the rebreather community.
“They’re passionate tech divers hungry for information,” explained Dr. Simon Mitchell, a professor of anesthesiology at the University of Auckland, New Zealand, who was one of the presenters. “That’s what I love about these types of meetings. I am happy to be here and share what I know.”
Taking a cue from the hyperbaric medical community, the meeting was organized to appeal to diver sensibilities; diving in the morning (8:30 a.m.- 2:00 p.m.), and lectures and discussion in the afternoon (3:00 p.m. – 7:00 p.m.) followed by dinner and drinks (9:00p.m. – 11:30 p.m. or later).
Dive Right In!
Donati and his crew did a masterful job of supporting more than twenty rebreather divers bearing scooters, cameras, and bailout bottles, along with a few open circuit divers, without incident. Their enthusiastic attitude and thoughtful attention to detail, whether it was solving specific problems with individual’s rebreathers, or bringing in attendees dry suit underwear hanging on the exterior of the boat before the after dinner rain hit, helped the operation run smoothly and efficiently while feeling relaxed. They were aided by Ponza Diving’s ubiquitous mascot, an amicable large black matif named Ugo.
The boat, which was docked just outside of the dive shop, headed out each morning around 8:30 a.m., as divers huddled over Italian espresso and fresh bread after prepping their breathers. Interestingly, as we were loading up the boat on the first day there, Donati made a point of warning both me and Peter Symes, publisher of X-Ray magazine, to go easy on the coffee. “It can kill you,” he said with all seriousness, citing an American diver who had a heart attack underwater after consuming too many cups of espresso. The boat then made its way to one of the numerous submerged seamounts covered in soft corals surrounding the island, where it would anchor for the morning dive.
Our morning dives were typically 165-261 ft/50-80m deep with one-to-two-hour run times. Visibility was 50-65 ft/15-20 m and water temperature was about 58-60°F/15-16°C. Following each dive, we were treated to a multi-course lunch, which usually included soup, fish, cephalopods, rice, pasta, bread, salad, and dessert, along with the requisite pitcher of wine and more espresso. After lunch, the boat headed back to port, where we prepped gear for the next day’s dive.
Where’s The Manzo, err Beef?
While rebreather diving in Ponza was clearly the attraction that brought people together, the presentations, given by some of the community’s leading scientists, engineers, and practitioners were the meat of the meeting. (Are you detecting a pattern here?) Our group met in an old stone chapel up the hill from the dive shop. Headphones were available for sequential English and Italian translation.
One of the themes that emerged from the meeting was the role of human factors, i.e. the way we process and act on and or fail to act on information, and its impact on diving safety. This is a deep body of knowledge that was developed in the aviation and healthcare fields and is now being applied to diving largely through the efforts of pioneer Gareth Lock at The Human Diver. Several of us noted that human factors were being discussed in the absence of the seemingly ubiquitous Lock, was a sign that this important work was beginning to gain traction. Here are some of the highlights.
Training Doesn’t Work: Technical Diving International (TDI) Rebreather Instructor, Instructor Trainer, and author Mark Powell began with a list of ten improvements in rebreather diving that he would like to see from a community perspective; things like better buoyancy control, the increased use of checklists, and more attention to bailout planning. He then asked the question, “Why hasn’t training made a difference?” That is, why hasn’t training produced permanent observable changes in divers’ behavior in these areas? The answer, documented by numerous studies, is that humans aren’t very good at retaining information.
The solution: deliberate practice of essential skills. “People tend to practice things they like and are good at, which is not very helpful,” Powell explained, noting that practicing things that are very difficult to do doesn’t work either. “The sweet spot,” he said, “is practicing things that are challenging.” He recommended that divers practice something on every dive! Sounded very GUE to me.
In-water Recompression (IWR): The use of in-water recompression to treat divers at remote locations has long been controversial, and until recently the hyperbaric medical community has failed to reach a conclusion regarding its efficacy. But as Simon Mitchell explained, the situation has now changed as a result of a new paper, “In-Water Recompression”, he co-authored with Dr. David Doolette, a decompression physiologist at the U.S. Navy Experimental Diving Unit (and a GUE diver). The two were able to find evidence not previously reported that answers two key questions:
- Does early recompression improve outcomes? (i.e. recompressing an injured diver within minutes vs hours)
- Is shallower, shorter recompression effective? (Note that IWR typically compresses the diver on 100% oxygen to 30 ft/9 m vs. a USN Table 6 to 60 ft/18 m.)
Based on U.S. Navy data derived in part from early research on treatment protocols, Mitchell and Doolette were able to answer both questions strongly in the affirmative. The new recommendation: A diver should be treated with IWR if a chamber is more than two hours away and the team is set up to provide IWR (i.e. has proper equipment such as full face mask and training, support, environmental conditions, and appropriate patent status).
Defensive Dive Profiling/Concerns for Aging Divers
Dr. Neal Pollock, research chair in hyperbaric and diving medicine at Université Laval, gave a pair of eye-opening lectures on the potential long-term impacts of decompression stress, what can be done, and the prospects for aging divers. Was he talking about us?
Pollock began by citing studies that found lesions in the brain and spinal cord have been observed with higher frequency in individuals with a history of repeated decompression stress. Bone lesions have also been found in commercial divers. The factors shown to increase the risk of dysbaric osteonecrosis in commercial divers were: a history of inadequate or experimental decompression, diving deeper than 165 ft/50 m, and a history of decompression sickness (DCS). The conclusion: while dysbaric osteonecrosis has largely been eliminated in commercial diving due to procedural changes, decompression stress poses a potential long-term risk factor for technical divers! Divers need to think about immediate and long-term risk.
As a result, Pollock, who is known for doing extra deco, encouraged divers to do longer shallow decompression adding, “It can’t hurt. It can only help.” Specifically, he recommended several ways of adding conservatism: using conservative gradient factors, primarily reducing GF-high, buffering the dive by slowing down on the final ascent to the surface following the last high pO2 stop, delaying exercise post-dive, extending surface intervals to add more time for recovery, using appropriate gasses (Yes, “air is for tires!”), choosing appropriate partners with similar risk tolerances, and maintaining good physical fitness.
The bottom line for aging divers; there is no upper age limit, though there may come a point where you need greater support. Be forewarned! Note, there were several post 65-year-old divers making the plunge at Ponza!
Human Factors In Rebreather Diving: Mitchell began by noting that human factors were the most important, but also the hardest, path to improving safety in rebreather diving. He then posed the question: Is there a safety problem with rebreather diving?
Mitchell began by reviewing what we know about rebreather safety based on the ground-breaking 2012 paper by Dr. Andrew Fock analyzing recreational rebreather deaths 1998-2010, to wit: There were approximately 20 deaths/year for 2000-2010 from a population, which was then estimated to be about 18,000 rebreather divers based on agency certifications. That means that the fatality rate for rebreather diving was estimated to be about 133 deaths/100,000 divers/year compared to about 16 deaths/100,000 divers/year for open circuit diving. The conclusion: rebreather diving was about 10x more hazardous than open circuit scuba. Note, there is currently a follow up study underway to determine if things have improved.
Mitchell broke down the causes of rebreather fatalities into three buckets:
• Hazards of advanced diving
• Rebreather equipment failures
• Diver error and violations
Overwhelmingly, most incidents arose from diver errors (Trying to do the right thing but doing the wrong thing) and violations (Knowingly creating unnecessary risk of harm to yourself and others, and expecting to get away with it). “I have made errors and violations in my rebreather diving,” Mitchell offered to the assembled group of divers, “and I bet you have too.”
What’s to be done?
Mitchell reviewed several fatalities involving violations, like diving with two-year old oxygen sensors, or using a type of sorb not specified by the manufacturer. He said that we needed to remove the motivation for violations. This involves a culture change: Make safe choices be seen as a strength versus a weakness. Training, mentoring, and role modeling are critical in this regard.
Typical errors might include forgetting to analyze one’s gas, forgetting to turn on the rebreather or open the oxygen valve, or leaving out an O-ring on the scrubber. In fact, each of these errors has resulted in multiple fatalities. Mitchell said that pre-dive checklists are the primary means for preventing errors. As a testament to the power, he cited a study analyzing the impact of using checklists in surgical suites: Deaths were reduced by 50% after the introduction of checklists, and as Mitchell pointed out, these were among highly trained professionals. He then cited a DAN study of some 2041 dives examining the impact of pre-dive checklist use on scuba mishaps; mishaps, including rapid ascents and low/out of air were reduced by 36%.
The barriers to using checklists?
First, misunderstanding about their purpose; checklists are not meant to replace a manual! Second, arrogance/ignorance; I can do it from memory, or I don’t make mistakes. Checklists can be supported by training, practice, and engineering.
Interestingly, after the meeting I asked one of the Italian rebreather divers if he used a checklist on our dives. “My instructor taught me to do it by memory,” the diver told me, “So that is what I do. I haven’t had any problems.” Until he does, and therein lies the problem.
Bruce Partridge, founder of Shearwater Research, also focused his talk on human factors and changing divers’ behaviors. He began by talking a little about the history of Shearwater, which got it start making rebreather controllers before venturing into dive computers. He then discussed the work involved in assuring that rebreather sub-systems like controllers meet safety requirements as part of the CE 14143 standard, which they published in a 2013 IEEE paper. Partridge said he believed that the CE 14134 standard was a really good thing for the rebreather industry. Interestingly, he pointed that there were approximately 600 failure modes possible on a rebreather, however, only 40 were equipment related; the remainder involve diver errors.
Explorer Edoardo Pavia, owner of Sea Dweller Divers, also spoke passionately about rebreather safety in light of human factors from his personal experiences. He began by speaking about British expedition leader Carl Spencer’s tragic death on the 2009 Britannic Expedition. Spencer mistakenly breathed an unmarked, high-oxygen content bailout cylinder at depth and convulsed and drowned. Pavia shared his views about the importance of following manufacturers’ rules and recommendations regarding checklists, oxygen sensors lifetime, scrubber duration, using proper sorb, and the importance of bailout out valves (BOV). He concluded that ignorance was “the hardest monster to defeat.”
Massimo “Max” Pieri, research supervisor for DAN Europe, presented their research focusing on preventing decompression illness (DCI) using DAN’s diving database of some 66,000 dives ranging in depth from 16-628 ft/5-192 m, average depth 100 ft/30 m. Some of the factors they have considered include: gradient factors, hydration, genetic disposition, and hematological parameters. They are also conducting a decompression study with a local (Italian) GUE group in cooperation with instructor Mario Arena, examining the efficacy of so-called “deep stops” vs shallow decompression profiles [See Dr. David Doolette’s post, “Gradient Factors in a Post-Deep Stops World,” in this blog issue for additional data].
Next, DAN Europe president Dr. Alessandro Marroni discussed his visionary program dubbed Advanced Virtually Assisted Telemedicine in Adverse Remoteness (AVATAR). Their goal is to develop tools and procedures to enable real-time monitoring of divers during their dives—think Fitbits on steroids! Marroni described his vision of a DAN doctor able to assess a diver who’s still in the water, and communicate directly with that diver via an underwater communications system. In fact, they have already tested prototypes.
Dott. Pasquale Longobardi, president of SIMI, also presented SIMI’s research examining the biochemical mechanisms involved in decompression stress. He concluded with a set of best practices, namely to run pO2s at 1.3 bar or less, maintain pN2s at 3.16 bar (the equivalent of breathing air at 100 ft/30 m) or less and run pHe as high as possible; Longobardi stated that helium in the form of trimix protects divers from oxidative stress (inflammation) compared to diving air (kick those tires again!). A colleague in the audience told me he had questions about the supporting data.
Having gotten our daily dose of brain food, attendees retired to their hotels and apartments to catch up on email, clean up, and later walk to the ristorante du jour that had been chosen for that evening. There we were greeted by our attentive hosts, Andrea and Daniela, accompanied by Ugo, who had arranged for a family-style dinner with wine and made sure that everyone had enough to eat and drink. If you had trekked to the meeting for the food alone, you would have not been disappointed.
“Mangia,” Dani told me gesturing emphatically with her hands and pointing to my empty plate, after the second, or was it the third course? “Please, you must eat some more,” she insisted passing me a bowl of mussels.” It felt like a family gathering—a family of passionate, geeky divers who were there to commune with their peers in celebration of l’arte e pratica che amiamo. And the eating and drinking and sharing of stories continued into the night.
Header Image: Marco Sieni.
X-Ray International Dive Magazine will be featuring more about the meeting and Ponza diving including some compelling images in their June issue.
Michael Menduno is InDepth’s executive editor and, an award-winning reporter and technologist who has written about diving and diving technology for 30 years. He coined the term “technical diving.” His magazine “aquaCORPS: The Journal for Technical Diving”(1990-1996), helped usher tech diving into mainstream sports diving. He also produced the first Tek, EUROTek, and ASIATek conferences, and organized Rebreather Forums 1.0 and 2.0. Michael received the OZTEKMedia Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012 and the TEKDive USA Media Award in 2018.
Undergoing PFO Surgery as a Team: Deana & Bert’s Excellent Adventure
People like to give GUE a hard time for their uncompromising focus on team diving. But a pair of divers from GUE Seattle has taken it to a new level: getting their PFOs fixed together. The team that bends together, mends together? Instructor and tech diver James D. Fraser willingly tells the tale.
by James D. Fraser
Header photo courtesy of Dr. Doug Ebersole
This is the follow-up to the story that ran in InDepth December, 2019: No Fault DCI? The Story of My Wife’s PFO
It has been a year since my wife Deana had a decompression illness (DCI) hit in Bonaire requiring her to do a Table 5 recompression profile in a hyperbaric chamber. At the time of my previous article’s publication, Deana had a Transthoracic Echocardiogram (TTE) bubble study and found out she did have a small to moderate patent foramen ovale (PFO). Two physicians offered similar options for Deana to consider when it came to her diving activities:
- Stop diving, as this eliminates any risk of DCI in the future.
- Modify her dive profiles to be more conservative: diving only once per day, diving nitrox 32 using air tables, and/or extending her decompression profiles and safety stops.
- Have the PFO repaired, knowing it is not a guarantee, and continue diving as conservatively as possible.
Deana had initially decided to wait on doing a PFO closure until after our daughter’s wedding in March 2020, but she realized very quickly that being “conservative” was not in her nature. Deana had already returned to diving within 12 days of her hyperbaric chamber ride. In the 46 days since her treatment, Deana had already done another 15 dives to depths of 90 feet; being conservative really was proving to not be an option for her. Diving was just too much a part of her life.
In mid-November, Deana reached out to cardiologist and tech diving instructor Dr. Doug Ebersole for a second opinion on the bubble study and his advice about her options. Dr. Ebersole gave Deana the same response as the other physicians; but, knowing Deana and her passion for diving, he suggested that she have her PFO fixed, since her plan was to continue diving.
Deana also spent time talking to other divers who had been diagnosed with PFOs—some who had them repaired and some who had decided against it—in order to get a more complete picture from both a patient and a doctor point of view. One of the final conversations that pushed Deana to have her PFO repaired was with a coworker who was a nurse practitioner in cardiology with knowledge of PFOs and diving. Her coworker was pretty blunt, stating, “Why are you playing Russian Roulette? You have worked in cardiac and know the risks.”
Some of these risks include Arterial Gas Embolism (AGE), Venous Gas Embolism (VGE), and cerebral embolism. That was the final “Aha” moment to tip the scale and get Deana to schedule her PFO repair, since “Russian Roulette” was exactly what Deana was doing based on her diving activities following her DCI hit.
Team Approach to Treatment
Bert Berzicha, one of our GUE Seattle community members, also completed his TTE as a result of having had some symptoms of DCI in the past. The test confirmed the presence of a large PFO. Deana and Bert compared notes initially and discussed diving as a team on future dives using more conservative decompression profiles than other teams, allowing the other teams to get out of the water sooner. Deana, however, related what she had learned from talking with her coworker and changed her mind about diving conservatively and instead decided to get the PFO repaired.
Deana did not want to take the risk of neurological deficits that could be irreversible. Deana suggested to Bert that he come with her to have his PFO repaired at the same time. Bert continued to research the subject, looked at his work schedule, and decided doing a “team” procedure made sense. Just as a dive team shares a plan, resources, and emergency procedures, a medical procedure shares similar benefits when working as a team.
It was time to plan a date for both of them to have the procedure. Deana and Bert both live in the Seattle area. Dr. Ebersole lives in Lakeland, Florida, so logistics included time off work, pre- and post-surgical care, flights, hotels, and transportation. Deana arranged to have her sister Jessica fly into Tampa from Dallas, prior to them arriving, so she could pick them up from the airport to make it to the hospital in time for the procedure. I was going to be in Australia on a business trip at the time, so I was not able to be there pre-surgery. I ended up reworking my return trip and flew from Canberra, AU to San Francisco, then on to Tampa, to land just an hour after their surgeries were finished and meet them back at the hotel.
Even though Deana and Bert could fly home 24 hours after the procedure, they decided to stay the weekend just in case there were any complications and to take it easy. Deana, however, had a different take on “easy.” The morning after surgery, Deana was invited by Dr. Ebersole to watch a procedure that he and his team perform called the “WATCHMAN” procedure (less than 24 hours after post-op). Then we picked up Bert and Jessica, and jumped into the truck to do a 300-mile, five-hour road trip to High Springs, FL, to take a tour of the Halcyon facility and say “Hi” to Orie Braun, Lauren Fanning, and Mark Messersmith; stop in at Global Underwater Explorers (GUE) HQ to buy some swag; and drive down to Ginnie Springs to see where Cave 1 may take place in Deana’s and my near future. Not bad a day after surgery.
It was at Ginnie Springs where Bert came to Deana and stated he thought he had active bleeding. We all paused and turned pale, knowing we were not in a great location for this to be happening, but after being assessed by Deana it turned out to be post-op bruising from the surgery. This did, however, make us stop and think, “We just drove 300 miles away from the hospital we had decided to be close to in case of complications.” I am sure Gareth Lock would find a really good human factors story in there somewhere.
Deana’s PFO adventure Timeline
- OCT 8: 47 m/153 ft technical dive resulting in a DCI episode requiring recompression.
- OCT 20: First dive post-chamber ride to 16 m/52 ft
- OCT 29: TTE Bubble Study; “Deana has a small to moderate PFO”
- NOV 17: Dr. Ebersole receives Deana’s TTE study for a second opinion
- NOV 21: Deanna dives now to 28 m/90 ft
- DEC 4: Last dive before PFO repair. In the 46 days since her hyperbaric treatment Deana made 15 dives: “Conservative Not”
- DEC 12: Deana and Bert have PFO procedure
- DEC 13: Lakeland to High Springs road trip
- JAN 27: First dive post closure—15 m/49 ft and spaced dives 2-3 days apart
- FEB 15: Started doing multiple dives daily no greater 15 m/50 ft
- MAR 8: PFO follow-up; OFFICIALLY cleared by Dr Ebersole to dive
- MAY 7: Dives now pushing 30 m/100 ft
- MAY 31: First Tec dive to 33 m/110 ft
Since May, Deana has done 120 dives in 2020 with a max depth of 52 m/170ft, which she did on September 12. Deana has gone back to no-restriction diving and has completed 16 technical dives since this summer. Some of these have been assisting with photogrammetry dives.
- 46 m/150 ft to 52 m/170 ft: 3 dives
- 40 m/130 ft to 46 m/150 ft: 5 dives
- 30 m/100 ft to 40 m/130 ft: 8 dives
Getting Personal With PFOs
COVID-19 has prevented us from doing a dive trip this year, which is the one main test we still have yet to do: repeat the scenario that always led to her getting DCI, which was three consecutive days of recreation and tech dives, to see if she experiences any recurrence of DCI symptoms. 2021 will hopefully open up this opportunity, or by that time Deana will already be training for GUE’s Tech 2 course. In either case, Deana and Bert are both very happy to have had their PFOs repaired; both have seen improvements in their health in other areas such as endurance, no longer being easily winded, and, in Bert’s case, less headaches, which he had prior to the PFO closure.
To get a PFO repaired is a personal choice, and no one should ever take surgery lightly as it has its own risks. Divers with PFOs need to do their own research and consult an interventional cardiologist, such as Dr. Ebersole, who understands diving. Only then can they make an informed choice based on their own unique situation whether or not a PFO closure is right for them. This article is meant to show the process and outcome of two very experienced and ambitious divers who made the choice to have their PFO repaired and the results of that decision.
Diving and Hyperbaric Medicine: The effectiveness of risk mitigation interventions in divers with persistent (patent) foramen ovale by George Anderson, Douglas Ebersole, Derek Covington and Petar J Denoble. 2019 Jun 30.
Alert Diver: PFO Study Update by Petar J Denoble
Alert Diver: Cases studies of divers who had their PFOs closed with transcatheter-applied occluders: Divers with Holes in their Hearts by Petar J Denoble 2010
James D. Fraser is a GUE Fundamentals and Rec 1/2 Instructor, PADI MSDT, and NAUI Scuba Instructor, and has been diving in the Pacific Northwest for over 30 years. James currently lives in Seattle, WA, with his wife and dive teammate Deana Fraser. As a member of the GUE Seattle Board of Directors, James is able to share his experiences and work with Deana at growing the local diving community sharing their passion with all who are interested. James recently embraced technical diving, becoming certified as a Technical 1 diver with GUE. James and Deana have had opportunities to travel all over the world to experience their passion in amazing places such as Egypt and the Maldives. James currently works as a Cyber Security Director with a Fortune 500 Defense Contractor and has been a residential construction business owner and Emergency Medical Technician (EMT).
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