Diving after DCS

[Duke Dive Medicine]

Thank you for your helpful comments.

The test my husband had was a Transthoracic Echocardiogram. Quoted from the report: "An agitated saline study (bubble study) was performed with and without Valsalva, and was inconclusive in determining if a small shunt (PFO) is present."

My husband remembers only 1 skin bends episode, but I think there may have been another. This is all in retrospect-- if we had known about skin bends at the time, we would not have brushed it off. We just thought something was odd. He doesn't remember any rash, but just a weird skin feeling on his abdomen a few hours after diving.

Both physicians he saw checked the computer profiles from his dives in Cozumel and nothing was an obvious cause of the DCS. The thing that was different on that trip was that we were diving with a company that gave us big tanks, so our dives were longer than usual. There were also big currents that week so every dive was more strenuous than usual and some days it was really ripping current.

We thought our diving days were over when he got the recent DCS hit in Cozumel. But when we asked the hyperbaric physician in Coz if he could ever dive again, he answered enthusiastically "Absolutely!". He characterized the DCS hit as 'mild'. We had a dive boat trip for the Galapagos booked and asked him about it. He didn't see any problem with my husband going but advised diving very conservatively. In the end, we decided to cancel the trip since we thought it might be too risky.

At my husband's age of 73, we didn't think we had enough years of diving ahead to justify the more invasive PFO test and subsequent PFO closure if one was found. Cost is not at issue at all-- it was more about the procedure and surgery risks weighed against the risk of diving super conservatively. Both dive physicians have been very supportive of my husband continuing to dive or we would not even consider it. But obviously, we are still trying to figure out the way forward.

You're most welcome, and thanks for clarifying what type of PFO test he had. TTE with agitated saline aka bubble contrast is what we normally recommend for PFO testing for divers, though some cardiologists prefer transesophageal echo. An inconclusive result isn't the same as not having a PFO, and it sounds like you all are proceeding as if he does have one, which seems reasonable.

For what it's worth, we would not characterize inner ear DCS as mild. Maybe they called it that because it resolved with hyperbaric oxygen, but that's probably more a function of quick recognition and treatment.

Strenuous exercise at depth is definitely a risk factor for DCS and adds a layer of complexity to your husband's case. Combine that with the fact that his symptoms didn't start until several hours after the dive, and the question of whether a maybe-PFO is at fault becomes a little muddier. Maybe something to discuss with the diving physician. It sounds like he's in good hands and you both are very engaged in his care.

Best regards,
DDM

 

[lizardland]

He said monitoring O2 exposure in rec divers has zero value = irrelevant. Not the same as "unlikely".

You're arguing over semantics. I'll make my statement clearer, a single cylinder recreational nitrox diver will die of boredom before they dive from exceeding the CNS oxygen exposure limits.

 

[Maolli]

You're arguing over semantics. I'll make my statement clearer, a single cylinder recreational nitrox diver will die of boredom before they dive from exceeding the CNS oxygen exposure limits.

Then why do we rec divers bother with MOD tables and calculations and set our computers for certain PO2 levels if excessive O2 exposure never happens?

 

[hiker11]

We are on a diving trip right now and 2 divers that were diving with our chosen dive charter got bent following two different dives, neither of which were anywhere close to ndl limits.

It's important to find out why these things happen if you will continue to dive and that means paying for the PFO test even if insurance doesn't cover it. This is not a time to be frugal.

You're most welcome, and thanks for clarifying what type of PFO test he had. TTE with agitated saline aka bubble contrast is what we normally recommend for PFO testing for divers, though some cardiologists prefer transesophageal echo. An inconclusive result isn't the same as not having a PFO, and it sounds like you all are proceeding as if he does have one, which seems reasonable.

For what it's worth, we would not characterize inner ear DCS as mild. Maybe they called it that because it resolved with hyperbaric oxygen, but that's probably more a function of quick recognition and treatment.

Strenuous exercise at depth is definitely a risk factor for DCS and adds a layer of complexity to your husband's case. Combine that with the fact that his symptoms didn't start until several hours after the dive, and the question of whether a maybe-PFO is at fault becomes a little muddier. Maybe something to discuss with the diving physician. It sounds like he's in good hands and you both are very engaged in his care.

Best regards,
DDM

I asked the physician why he characterized it as 'mild' and he said because symptoms didn't come on till several hours after diving. It definitely didn't feel mild to my husband!

 

[Maolli]

I asked the physician why he characterized it as 'mild' and he said because symptoms didn't come on till several hours after diving. It definitely didn't feel mild to my husband!

That's very odd. I've never heard of symptoms being graded for severity because of how long they take to show up.

I mean if someone feels faint and 24 hours later they have a stroke does that mean it's mild?

 

[tursiops]

Then why do we rec divers bother with MOD tables and calculations and set our computers for certain PO2 levels if excessive O2 exposure never happens?

You are mixing up terms again. The MOD issue is caused by high PPO2; the O2 exposure issue is caused by moderate PPO2 for a long time. Yes, in both case, you ae "exposed" to O2. But the term "O2 exposure" is usually reserved for long periods of moderate PPO2.

 

[hiker11]

What was it set on before?

Was at medium conservatism of GF 40/85. Now switched to 35/75.

 

[Duke Dive Medicine]

I asked the physician why he characterized it as 'mild' and he said because symptoms didn't come on till several hours after diving. It definitely didn't feel mild to my husband!

I'd agree with @Maolli above... symptom onset time is less relevant than the presentation. But, that's semantics. He got treated and got better so that's what counts.

Best regards,
DDM

 

[uncfnp]

Was at medium conservatism of GF 40/85. Now switched to 35/75.

I once had a fairly significant skin bend episode in Cozumel when I walked downtown after a two tank morning dive. I remember it was very hot and feeling over heated with rash onset shortly after.

Don’t forget that dive profile is just one of many factors to consider.

 

[lizardland]

Then why do we rec divers bother with MOD tables and calculations and set our computers for certain PO2 levels if excessive O2 exposure never happens?

Given your posts in the other thread, I think you know the answer to that but are just looking for an argument.

You have an allowance of red gummy bears you can have in a day before you start bouncing off the walls. Exceeding the safe pO2 limits means you get all your red gummy bears in one go and your parents lock you outside while they turn the TV up. Or you can dive within safe pO2 limits, in which case if you keep an eye on how many red gummy bears you are eating and if you eat them slowly enough you will never reach a point where you will be bouncing off the walls and your parents will pretend they love you. Recreational divers eat red gummy bears at such a slow rate that counting them is pointless.

You sound like you eat all your red gummy bears at once.