If any dive could be described as routine, this one qualified. My wife, Karen, and I descended on Gorda Banks, a seamount off San Jose Del Cabo in Baja, Mexico, hoping for some water column action. But there was no current, which meant no schooling hammerheads, or any kind of sharks, or even schools of bonito.
With a strong current, this can be an exciting dive; without one it becomes less than routine. So we reluctantly dropped to the high point, at about 120 feet, and skimmed the top of the seamount. We couldn’t have been more relaxed, and when our computers showed we were nearing no-decompression limits, we started slowly up the anchor line, hand over hand. A one-minute safety stop at 60 feet was followed by another hand-over-hand ascent to 20 feet, where we made a three-minute safety stop. Both of our computers had cleared well before we reached 30 feet.
About 10 minutes after surfacing, I noticed a slight discomfort in my right shoulder. It wasn’t really pain; it just felt as though my wetsuit was too tight. So I unzipped the back of my suit, but that uncomfortable feeling persisted. I even stood up in the inflatable to make sure my legs were working.
The ride back to the dive boat took about 20 minutes. As I pulled myself up to the swim step, my legs felt as though they were made of rubber. I grabbed the rail. Karen grabbed me by the other arm and offered to help me to a deck chair. I told her, “I’m not going to make it that far, just lay me on the deck.” Within a couple of minutes the crew had placed me on oxygen.
I breathed oxygen for nearly two hours and was really scared. I occasionally moved my feet and legs to make sure they still worked. They did. After a while I started shivering, so the crew helped me to a cabin and covered me with blankets. By this time I was walking, but I felt very unsteady.
Finally I stood up, gingerly at first, then went up to the deck and began pacing back and forth. No pain, no unusual symptoms. Everything felt normal. But that was too close a call to just walk away, so I called DAN® on my cell phone. The people at DAN agreed and referred me to the recompression chamber at Hospital Especialidades in Cabo San Lucas. The boat crew gave me a small oxygen bottle to suck on during the 45-minute ride to the chamber.
We were met there by Antonio Luevanos, the head of the chamber project, and Abraham Bustamante, the chamber operator. By day, Luevanos is the assistant city manager, but he’s personable and a total pro when it comes to chamber treatment. He gave me a thorough neurological exam that included walking on my toes and heels, coordination tests and reflex and sensation exams. Everything seemed fine.
It looked like the oxygen had done the job, and I dodged a bullet again. [Medical note: Typically, hyperbaric treatment is still recommended even if the symptoms resolved completely with surface oxygen. There is a risk of the symptoms returning. However, the decision ultimately has to be made by the clinical personnel evaluating the diver.]
When Karen and I returned to our hotel, things began deteriorating. My legs started feeling numb, and I felt tingling in my hands and feet. I called Luevanos, and he told me what I’d expected: Come back to the hospital for a chamber treatment.
The chamber in Cabo is a narrow tube about 15 feet long, divided into two compartments with an open hatch between them. It’s tall enough to sit up in with a bit of headroom, but in no way can an adult stand. The floor is covered with mattresses and sheets, along with many pillows. I was told to remove anything metal, including my watch and glasses, because a spark could ignite a fire in the high oxygen compartment. Roxanna, the attendant, and I dressed in surgical scrubs and crawled into the rear compartment. The protocol called for a U.S. Navy Treatment Table 6 recompression — nearly five hours at 60 and 30 feet, most of it breathing from a half-face oxygen mask.
I had been in practice chamber runs, so most of the procedure was no surprise. Descent to 60 feet was slow enough to clear my ears, although it took lots of nose holding and blowing. As air is compressed it heats up, so the atmosphere seemed thick and humid. Every five minutes or so, stale air is sucked out and fresh air injected. A lot of my sweat was from apprehension. Had I made my final dive? Would I be able to drive my new Porsche Boxster? Would I even be able to walk up the stairs at home?
Roxanna’s English was far better than my Spanish, so that was our language of communication. She is a marine biologist working for the Baja nature reserve; she moonlights in the chamber. She was a calming presence in this strange setting.
I had breathed through many apparatuses underwater through the years, but never anything as frustrating as that mask. It seemed as though I had to fight for every breath; there was never enough gas. My mouth was as dry as the Baja desert, but the mask couldn’t be removed for drinking water until the 20-minute oxygen period was up.
Bustamante, the chamber operator, had set up a digital projector to show a movie on the chamber wall, but between the noise of breathing and the struggle to get oxygen, I couldn’t focus on it. Each of the 20-minute oxygen cycles (with five-minute breaks in between) seemed like an hour. And there were five more of those to go before moving up to 30 feet. I thought there was no way I’d make it through five hours.
The breaks are designed to give the body a respite from the pure oxygen and to reduce the potential risk of oxygen toxicity. During one break I asked Roxanna about breathing techniques, and I also analyzed what I was doing. First, I decided I was probably breathing too fast and shallow, building up dead air space. The next step I adjusted seemed counterintuitive with a mask on: breathe through my nose. It took several cycles to get comfortable, but I finally came to terms with the mask. I laid down with my head propped up, did all the breathing through my nose, and did it very slowly. It worked to the point that I was totally relaxed and almost went to sleep. There was no dryness, and I was able to get through an entire treatment on only one bottle of water.
From what I’d read, I expected the symptoms to disappear under pressure. That didn’t happen. Most of the symptoms were still there after the first Table 6 treatment, so they checked me into the hospital. It was a pretty basic facility, only 10 beds, but I had my own room, and the staff did the best they could with my rudimentary Spanish.
I didn’t sleep much that night. Occasionally I would get up and walk the short hall outside my room. My balance was off; I had an unsteady gait. The tingling and numbness in my hands, legs and feet was increasing. This wasn’t supposed to happen after a chamber treatment. [Medical note: It is very typical for decompression sickness with serious neurological symptoms to require multiple treatments. It is also not unusual for symptoms to reduce but not completely resolve while at depth in the chamber.]
The next morning, Luevanos explained that decompression sickness doesn’t necessarily follow a pattern. Most likely the bubbles were gone, but nerve tissue was damaged, and the therapy for that is high-pressure oxygen. Another Table 6 treatment relieved the symptoms somewhat, and later that day I again walked the hall, repeating parts of Luevanos’s neurological tests on my own, walking on toes and heels and balancing on one leg. Some attempts were better than others, but improvement continued slowly during the course of the day.
During my second day in the hospital, I was examined by a neurologist. I still had problems differentiating between sharp and dull sensations on parts of my legs. Some reflexes were abnormal, and coordination of my left hand was a little off. But balance and walking had improved.
After a second night I left the hospital. Luevanos said there was no longer a reason to look at plain hospital walls when I could be enjoying myself in Cabo. The only restrictions: no alcohol, caffeine or spicy food, no exercise or exertion, and stay out of the sun. But, I was told, be sure to enjoy yourself!
As the day went on, my symptoms gradually faded. I still reported to the hospital for chamber treatments, but they were now Table 5, each lasting about two hours. By this time I was relaxed enough to watch movies on the chamber wall. The dialogue was in Spanish with English subtitles, so Roxanna and I were able to work on our language skills. As we continually giggled our way through Hot Fuzz, the people outside were encouraged that the treatment was working.
In all, I had five chamber treatments over five days. I had read that symptoms disappear at depth in the chamber, but I didn’t actually feel that until the fourth day, when the numbness in my legs receded and feeling gradually returned. Until then, most of the improvement came during the day, away from the chamber.
The general recommendation regarding flying after hyperbaric treatment is to wait 72 hours after the last chamber treatment, so we incurred three additional days of hotel and meal expenses and a penalty for changing the return flight.
I have been a DAN Member for nearly 20 years and never before this incident had I used the services. I’ve always been a DAN fan, but they really came through for me. The chamber crew contacted DAN headquarters every day, and I called on several occasions with questions, which the medical on-call staff patiently answered.
When I returned home I saw Karen Van Hoesen, M.D., at the Hyperbaric Center at the University of California San Diego Medical Center. This time the neurological exam was normal, and I was cleared for all activities except diving, which had to wait four to six weeks. Van Hoesen strongly suggested diving nitrox using air settings on my computer.
Since that time I’ve been on three dive trips, including one where nitrox wasn’t available. On that occasion, conservative profiles and six-minute safety stops kept me out of trouble.
So what did I learn from this experience?
Decompression sickness is unpredictable. You can’t beat the odds all the time, especially when you qualify for senior citizen discounts. My wife and I had made the identical dive; she was fine, but I got bent. I’ve made more than 5,000 dives over 50 years, many of which should have resulted in decompression sickness but didn’t. As recently as three years before, I’d done a week of heavy-duty decompression diving at Bikini Atoll. But now my deep diving days are done. Besides, the light for video and photography is better on the sunny side of 80 feet.
*The incidents covered in this column are real and submitted by members of DAN but are subject to editing. Some names and details may be omitted to preserve confidentiality. We present these cases to remind you that DAN is available 24/7, to help with medical emergencies, arrange hyperbaric treatment and facilitate emergency evacuation through the DAN Emergency Hotline.
When I got the call from Eric Hanauer, I advised him to get to the closest hospital or the hyperbaric facility in Cabo as soon as he could. Even though he was asymptomatic at the time, we often see a return in symptoms when a patient with decompression sickness (DCS) is treated with surface-level oxygen only. In cases where symptoms begin as soon after the dive as his did (10 minutes) and manifest as significant weakness, a relapse is especially likely.
When we spoke again five hours later, I was glad to hear Hanauer had done the safe thing and gone to the chamber for evaluation. I was sorry to hear that his symptoms had returned. It’s not always easy to convince somebody to seek medical attention, especially after leaving the hospital only a few hours earlier, but Hanauer was a good sport and very aware of the potential severity of his symptoms. A few hours later, I got a call from Antonio Luevanos. I was not at all surprised to hear that Hanauer was in the chamber receiving a Table 6. We discussed options for follow-up treatments and made a plan to discuss Hanauer’s progress and provide further treatment consultation the next morning.
Hanauer’s perspective on the events he describes is an enlightened one. Odds really do play more of a role in DCS risk than we would like them to. When it comes down to it, DCS is quite probabilistic. The more we take steps to minimize our nitrogen load, the more we increase our chances of avoiding DCS.
— Brian Harper, EMT, DMT
© Alert Diver — Q1 Winter 2010