Diving after DCS

[Macfod]

We're trying to figure out how to approach diving after an 'undeserved' DCS hit in Cozumel a few months ago. My husband spent 9 hours in the chamber (one 5hr ride + two 2-hr rides) after experiencing severe vertigo several hours after diving. Much of the vertigo was gone after oxygen. He was 95% recovered after the hyperbaric treatments. He was 100% within a couple weeks of returning home.

Both the hyperbaric doc in Coz and the one he saw when we got home said he could continue diving but should be more conservative. We now think he had one or two episodes of skin bends on previous dive trips. He also has a lifelong history of migraines, with occasional aura, which is often associated with PFOs. So I'm pretty convinced he has a small PFO. But the simple test for a PFO didn't show a problem. He did not get the definitive PFO test as that is more invasive. He's 73 YO, so even if he had a PFO, he wouldn't have it repaired as the surgery has some risk. My question to others who have been down this path at this age-- what are your limits? Do you still dive in remote locations like Raja Ampat? Do you still go do dive boat trips? Or should we avoid going too far afield?

We were already conservative divers and have always followed all the rules to a T. Based on the doctor's recommendations, we are now doing longer safety stops (5+ minutes), shorter dives (50 minutes), shallower dives (max 60'), super slow ascents, diving Nitrox (but setting our computers to O2), only doing 2 dives per day, taking a day off every few days, being extra careful about hydration, not doing any exercise post-dive (not even climbing the ladder with gear on), & no warm showers, etc. We will hire private guides to make sure we can dive the profile we need. My husband is in good physical shape, is normal weight, swims or exercises 5-7x per week and doesn't drink. He has logged 300 dives, with most of those in the past 5 years. We'd like to continue diving a few more years but want to figure out the safest way to do it.

We just got back from a dive trip in Loreto/ Baja. They didn't have Nitrox so we just did super shallow dives-- 30-50'. We did 2 dives per day/ 4 days in a row. No problems. We have an upcoming trip to the Maldives. We are hiring private guides to insure that we can tailor the dives to our needs.

I would love to hear others' experiences after DCS and how they choose where they dive and what boundaries they have adopted. We would love to go back to Fiji, Raja Ampat, French Polynesia, western Australia, but don't want to be too far from a chamber. Any advice would be appreciated.

Sounds like doing it all right. No nitrox is a problem though and would limit diving to 15m
I had initial test with tube down throat but no evidence so they tried saline test.. there the bubbles were.
Seven years later I limit dives to 2 max and at least 3 hours service interval.
No currents also.
The biggy is after diving. Gear off and chill for 2/3 hours.
I occasionally get a skin bend but have put it down to my error in staying too deep or as yesterday a short dive and exiting with all gear!
Your body reminds you.

 

[Dominik_E]

Do not want to state anything that may be obvious, but: it is after a single DCS incident simply not possible to pinpoint "the cause" with absolute certainty. Sure, sometimes there may be a strong suspicion, e.g. a very aggressive profile (just to name something where there will be little dispute). But DCS happens with some regularity also to divers that are completey within all physical "norms", dive conservative profiles, and adhere to any and all resommendations. What follows is not statistically completely correct, but gives food for thought: we implicitly accept something like one DCS incident per few thousand dives at least, even if all rules and procedures are followed. Because if we would accept only zero, we could never dive. This acceptance comes with consequences. If we would send a million fresh, healthy AOWDs on a fun dive, give or take one hundred people would afterwards be bent. Every single one of them would have deep and nagging questions about "the cause", what "went wrong" and "how to avoid". Every single one would probably want to ask "why me?". Sadly, Nature sometimes will not yield her secrets.

Among those 100 bent divers, we would surely expect at least 25 to have a PFO. Why? Because about 25% (20...30%) of all humans have one. As it is a known and established risk factor, my expectation would be we indeed find substantially more than 25% to have one, if the test was really made. But not all. And even more confusing, not for all that were bent and later found out that they have a PFO, the PFO would really have been "the cause". At least sometimes, it would just be a chance discovery. Finding something very frequent (PFO) present when something very rare (DCS) happens always conveys limited information. Unless one has a huge amount of data, a luxury we often do not enjoy.

This is not to say I would not understand the desire to avoid a future incident. This is very human! But it is to say I would if it was me try not to focus on one, or a few things. And whatever is found and done, I would work towards the goal of if I ever get hit again, being able to accept that I may just on that day and in that hour have been one of the 100.

Maybe it helps to think about options that with very high probability will reduce the baseline risk, whatever it may be in the individual case? Diving conservative profiles (slow ascends in the shallow portions, extended stay at 3 to 5m even if it was a dive within NDL, diving nitrox but adhering to air NDLs, surfacing very slowly), avoiding exercise in the hour after a dive, allowing for 2 hour+ surface intervalls have I think been mentioned in the thread. I can not really imagine a case where those would increase the risk, and would be near certain that they will decrease it.

 

[boulderjohn]

Do not want to state anything that may be obvious, but: it is after a single DCS incident simply not possible to pinpoint "the cause" with absolute certainty. Sure, sometimes there may be a strong suspicion, e.g. a very aggressive profile (just to name something where there will be little dispute). But DCS happens with some regularity also to divers that are completey within all physical "norms", dive conservative profiles, and adhere to any and all resommendations.

I dove for many, many years without anything close to DCS, and many of those dives would be considered aggressive. Then one day I did a 2-tank dive within NDLs, and, just on a whim, I took an oxygen bottle I had on hand and used it for the safety stops. I should have been very safe, but I got bent.

It took several hours for symptoms to appear, and the first symptom was highly unusual--a sharp pain in the bottom of my right scapula. I actually treated myself with that oxygen bottle and got some relief. I would have continued on my own if Duke Dive Medicine hadn't knocked some sense into me and sent me to a chamber. The biggest reason for my denial was the fact that the dives should have been so very safe. (I already knew I did not have a PFO.)

I was told to wait several months (don't recall exactly) before diving again. I have completed many dives since then, without feeling a concern over DCS. I developed a theory that some cases of DCS are essentially flukes, like taking a sip of water and having some of it "go down the wrong hole" and making you choke. I can't explain it, but I'm not worried about it.

 

[tursiops]

I dove for many, many years without anything close to DCS, and many of those dives would be considered aggressive. Then one day I did a 2-tank dive within NDLs, and, just on a whim, I took an oxygen bottle I had on hand and used it for the safety stops. I should have been very safe, but I got bent.

It took several hours for symptoms to appear, and the first symptom was highly unusual--a sharp pain in the bottom of my right scapula. I actually treated myself with that oxygen bottle and got some relief. I would have continued on my own if Duke Dive Medicine hadn't knocked some sense into me and sent me to a chamber. The biggest reason for my denial was the fact that the dives should have been so very safe. (I already knew I did not have a PFO.)

I was told to wait several months (don't recall exactly) before diving again. I have completed many dives since then, without feeling a concern over DCS. I developed a theory that some cases of DCS are essentially flukes, like taking a sip of water and having some of it "go down the wrong hole" and making you choke. I can't explain it, but I'm not worried about it.

I find myself increasingly interested in dive locations that have a chamber handy.

 

[hiker11]

Sounds like doing it all right. No nitrox is a problem though and would limit diving to 15m
I had initial test with tube down throat but no evidence so they tried saline test.. there the bubbles were.
Seven years later I limit dives to 2 max and at least 3 hours service interval.
No currents also.
The biggy is after diving. Gear off and chill for 2/3 hours.
I occasionally get a skin bend but have put it down to my error in staying too deep or as yesterday a short dive and exiting with all gear!
Your body reminds you.

Thanks for your comment. It's exactly what I was hoping for-- to hear from someone else that has been down this road and how you are managing it. We definitely plan to avoid strong current as we think that might have been a contributor. We used to always climb the ladder with our gear on but are not doing that anymore.

So you do a max of two dives per day, ie. a morning and afternoon dive with a longer 2-3 hour interval between? A 2-3 hour interval not been suggested by his docs but sounds like a good safe approach.

You didn't mention where you generally dive and how far you are from a chamber. I feel like we got lucky being in Cozumel when this happened since the chamber was only a few minutes down the road. We have been diving in a number of remote locations the last few years (Raja Ampat, Tavuni, etc.) but have sadly concluded that those are now likely off-limits. That said, I have not yet decided how far away we are willing to be from a chamber. Now days, when we think about diving, the first thing we do is google the location of the nearest chamber. Even for diving in Kona, the nearest chamber is in Oahu, which requires a flight....

 

[Outbound]

Yes, if desired, by most agencies. People do still use them.

But what we are talking about is strategies for decreasing risk in a DCS-prone individual.
Air tables while diving Nitrox are cheap, simple, reliable, easy, and more conservative than most computers.

There is no universe in which “use air tables” is easier for the diver than “dive nitrox on air computer setting.” If the goal is to add conservatism in the simplest - and thus most likely to be followed - manner, then suggesting tables sure ain’t the way.

 

[Dominik_E]

The thing that in effect sometimes makes table-dives quite „conservative“ is that one is motivated to assume a box-style profile even if it is a multi-level dive. This can result in effectively short NDLs. Exaggerated example: Diver briefly goes to 30m to check on a nice gorgonia. After 4 minutes total, diver quickly ascends to 18m and spends the rest of the dive checking on moray eels there. If done according to tables, it will be a „30m dive“ with a short NDL (give or take quarter of an hour), and thus an overall short dive. A computer will give a much longer NDL. If that longer (arguably more „correct“) computer NDL is really used, the diver will have a higher nitrogen load, including slower tissues.

But this is not in itself a feat of the table. No one is forced to use up all of the NDL a computer gives, and everyone can set a computer to be more conservative. Staying farther away from the limits will in virtually all cases be safer, DCS-wise. Which is not at all surprising of course.