Question Deserved DCS hit even with deco cleared due to high exertion during the dive?
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Thank you all for your additional insights and comments; I also have some updates from my side with the last dives after the incident and some interesting findings after the last dive where I tried to replicate a similar dive like the one described in the first post (not the identical profile underwater, but the same conditions before and after the dive).
Let's start with some unanswered questions:
I also point out that I used the same O2 fill for another dive the week before without any issues (it was a deeper but slightly shorter dive, but still around 70 minutes total with 12 minutes of deco with oxygen).
I don't know if any studies tested situations like this one, it would be really interesting.
Also, thanks a lot @Dr Simon Mitchell for your insights, I look forward to reading the paper once it becomes public.
I'm also curious about the actual dive profiles used in the study and the effects of the high venous bubble load after a dive; that could also explain situations of "subclinical" DCS and/or being very tired after a dive, even if one already did the same dive profile before.
Diving after the DCS - recreational dives
After the incident, I took a full rest for a couple of weeks; then I went back to diving by doing some recreational dives using a wetsuit in warm water (~30°C / ~86°F), totaling a dozen dives in 9 days during a dive trip.
All dives were with air, max depth of 30 meters (100 ft), and used the same GF settings (50/80), but I almost always surfaced with a leading GF of 75% or less.
Fortunately, I had zero issues and no DCS symptoms after the dives, even doing two dives per day with a ~1h surface interval.
Back from the dive trip, I did another recreational dive in the lake, max depth of 40 meters (130 ft) and a bottom temperature of ~7°C / 45°F, and had no issues again.
Diving after the DCS - first deco dive
Last weekend I did my first deco dive after the incident, and while the profile wasn't the same as the dive where I suffered DCS symptoms the conditions were similar before and after the dive.
Dive to 50 meters (165 ft), using EAN50 and oxygen for decompression, and I surfaced with a GF of about 55%. I swam a bit fast on the bottom and made a very slow ascent from the last stop to the surface.
After the dive, I put back all the equipment and stayed for an hour or so chatting with the dive buddies and having a beer outside.
It was a sunny day, like the one where I got the DCS hit (where I had lunch outside and had direct sunlight), and again I stayed in the sun after the dive.
About a couple of hours after surfacing, I noticed that again I had swollen wrists, the left one was a bit more swollen than the right one.
Immediately I thought about a potential second hit, and started wondering what I did wrong and if I had any other symptoms in addition to the swelling.
For a moment I felt a bit of dizziness / a general feeling of anxiety, but I don't whether it was "psychological" or due to a potential DCS.
I was ready to breathe from my oxygen tank and checked for any other signs of DCS (e.g.: skin bends, rashes, etc.), but thankfully everything went back to normal, and also the swelling reduced in less than an hour.
Then, I realized what the actual cause of the swelling might be.
In this deco dive, I used two dive computers, one on each wrist, and the left one (the backup computer) had the elastic wristband way tighter than my primary computer and I also used a thicker undersuit (since it was a longer deco dive, compared to the recreational dive to 40 meters the week before).
This might potentially explain also the swelling in the dive with the DCS incident, where I used the same computers and the same undersuit, and I stayed longer in the water with a tight wristband.
To be clear, the symptoms were still different: in the dive with the DCS incident I felt the other symptoms (dizziness and anxiety) way before noticing the swelling, and I did exert way more during and after the dive whereas in this one I first noticed the swelling and after some minutes I started feeling anxiety about a possible second DCS hit.
And still, could the feeling of anxiety and minor dizziness be also due to "sunbathing" after the dive?
I don't know if reduced blood flow to the wrists due to the dive computer and the undersuit could "increase" the DCS risk, or at least reduce the quality of off-gassing during deco, or if the two effects are independent (e.g.: if I hadn't worn the second dive computer so tight and used a lighter undersuit in the dive with DCS, would I have had no swelling but only the other DCS symptoms? Or maybe the swelling and reduced blood flow "triggered" the other symptoms?).
Again, I know that it's impossible to pinpoint the exact cause(s) of the DCS hit, but this might help to understand what symptoms to look for after feeling "not perfectly well" after a dive. And consider also the effects of anxiety after noticing the first symptoms after a dive, which might not be directly caused by decompression sickness.
Let's start with some unanswered questions:
Yes, I tested the O2 again, it was 100% oxygen.
I also point out that I used the same O2 fill for another dive the week before without any issues (it was a deeper but slightly shorter dive, but still around 70 minutes total with 12 minutes of deco with oxygen).
That's an interesting remark, a couple of dive buddies once told me that for some people the accelerated deco profiles have a different effect than the same dive using only air to decompress.
I don't know if any studies tested situations like this one, it would be really interesting.
Also, thanks a lot @Dr Simon Mitchell for your insights, I look forward to reading the paper once it becomes public.
I'm also curious about the actual dive profiles used in the study and the effects of the high venous bubble load after a dive; that could also explain situations of "subclinical" DCS and/or being very tired after a dive, even if one already did the same dive profile before.
Diving after the DCS - recreational dives
After the incident, I took a full rest for a couple of weeks; then I went back to diving by doing some recreational dives using a wetsuit in warm water (~30°C / ~86°F), totaling a dozen dives in 9 days during a dive trip.
All dives were with air, max depth of 30 meters (100 ft), and used the same GF settings (50/80), but I almost always surfaced with a leading GF of 75% or less.
Fortunately, I had zero issues and no DCS symptoms after the dives, even doing two dives per day with a ~1h surface interval.
Back from the dive trip, I did another recreational dive in the lake, max depth of 40 meters (130 ft) and a bottom temperature of ~7°C / 45°F, and had no issues again.
Diving after the DCS - first deco dive
Last weekend I did my first deco dive after the incident, and while the profile wasn't the same as the dive where I suffered DCS symptoms the conditions were similar before and after the dive.
Dive to 50 meters (165 ft), using EAN50 and oxygen for decompression, and I surfaced with a GF of about 55%. I swam a bit fast on the bottom and made a very slow ascent from the last stop to the surface.
After the dive, I put back all the equipment and stayed for an hour or so chatting with the dive buddies and having a beer outside.
It was a sunny day, like the one where I got the DCS hit (where I had lunch outside and had direct sunlight), and again I stayed in the sun after the dive.
About a couple of hours after surfacing, I noticed that again I had swollen wrists, the left one was a bit more swollen than the right one.
Immediately I thought about a potential second hit, and started wondering what I did wrong and if I had any other symptoms in addition to the swelling.
For a moment I felt a bit of dizziness / a general feeling of anxiety, but I don't whether it was "psychological" or due to a potential DCS.
I was ready to breathe from my oxygen tank and checked for any other signs of DCS (e.g.: skin bends, rashes, etc.), but thankfully everything went back to normal, and also the swelling reduced in less than an hour.
Then, I realized what the actual cause of the swelling might be.
In this deco dive, I used two dive computers, one on each wrist, and the left one (the backup computer) had the elastic wristband way tighter than my primary computer and I also used a thicker undersuit (since it was a longer deco dive, compared to the recreational dive to 40 meters the week before).
This might potentially explain also the swelling in the dive with the DCS incident, where I used the same computers and the same undersuit, and I stayed longer in the water with a tight wristband.
To be clear, the symptoms were still different: in the dive with the DCS incident I felt the other symptoms (dizziness and anxiety) way before noticing the swelling, and I did exert way more during and after the dive whereas in this one I first noticed the swelling and after some minutes I started feeling anxiety about a possible second DCS hit.
And still, could the feeling of anxiety and minor dizziness be also due to "sunbathing" after the dive?
I don't know if reduced blood flow to the wrists due to the dive computer and the undersuit could "increase" the DCS risk, or at least reduce the quality of off-gassing during deco, or if the two effects are independent (e.g.: if I hadn't worn the second dive computer so tight and used a lighter undersuit in the dive with DCS, would I have had no swelling but only the other DCS symptoms? Or maybe the swelling and reduced blood flow "triggered" the other symptoms?).
Again, I know that it's impossible to pinpoint the exact cause(s) of the DCS hit, but this might help to understand what symptoms to look for after feeling "not perfectly well" after a dive. And consider also the effects of anxiety after noticing the first symptoms after a dive, which might not be directly caused by decompression sickness.
Do you dive a drysuit? How tight are your seals? Tight seals can cause both swelling in hands and a feeling of anxiety/dizziness.
This is one of the reasons for which I use a console, and I keep both my arms free from any instrument...
Yes, I almost always use a trilaminate drysuit with dry gloves, except for some hot water dives (like the last dive trip I mentioned in my last reply) where I use a classic wetsuit.
The latex seals are custom-fitted based on my wrists, I used the same seals for months without issues, and I don't know if maybe I've never noticed the swelling after the dives before.
Regarding the feeling of anxiety and dizziness, this happened to me about one hour after surfacing (and removing the dry suit).
justinthedeeps
Contributor
Not a diving observation, but I have occasionally experienced very swollen hands and unwell feelings following long coldwater swims or kayak races in a wetsuit. No compressed gas involved.
Similar to "screaming barfies"? (common for ice climbers)
In these cases it might be an inflammatory response following hand exertion with restricted circulation at very cold temperatures.
Not sure if that's on your radar, but in any case it does seem important to ensure adequate exposure protection + good, unrestricted circulation to the hands and feet, both for gas escape and other factors.
For diving, been using properly fitted drygloves with simple wool liners for up to 3 hours in ~7ºC including decompression, so far no 'hand hits'
Similar to "screaming barfies"? (common for ice climbers)
In these cases it might be an inflammatory response following hand exertion with restricted circulation at very cold temperatures.
Not sure if that's on your radar, but in any case it does seem important to ensure adequate exposure protection + good, unrestricted circulation to the hands and feet, both for gas escape and other factors.
For diving, been using properly fitted drygloves with simple wool liners for up to 3 hours in ~7ºC including decompression, so far no 'hand hits'
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