Confused by First experience of Decompression Illness

[AmyKB]

Just returned from diving weekend at Cabilao Island in the Philippines. 3 long dives over 2 days - Day 1: one dive in the afternoon max depth 26m; duration 66mins. Day 2: 1st dive 10.40am, max depth 27m; duration 72mins. Second dive 2.40pm, max depth 25.6m; duration 67mins. On all dives a well respectful safety stop between 3-6m - between 5-10 minutes long. All were no decompression dives. I came within 4 minutes of No Deco limit at deepest depth on both dives on Day 2. My computer advised me I ascended too quickly after the safety stop between 3m and surface on the last dive. Within an hour of surface time I experienced symptoms of DCI and ended up on oxygen for the rest of the evening and into the night.. in fact stayed hooked up to oxygen flow overnight. Symptoms included extremely sore torso (especially sore breasts), tingling in arms, numbness in legs, red splotches of colour on thighs and general dizziness when standing. The following morning all symptoms subsided and I did not go to a decompression chamber. Advice from DAN suggested DCI on what was termed 'provocative dives'. I am now left feeling utterly confused as I have certainly dived much closer to deco limits without experiencing DCI; further, on all dives, more than 20 minutes spent at shallower depths (10-15m). I may not have drunk enough water before the second day's first dive as it occurred right after breakfast. Is it possible for divers to develop greater susceptibility to DCI? Or was this really a risky dive plan and combined with my lack of water intake a predictable result? My buddy was fine, as were other divers in the group.

If anyone has any input or insight or even if you've had a similar experience I'd be really happy to hear it

 

[miketsp]

What computer were you using?
Was it set to normal or conservative?
If it's a Nitrox model are you sure it was set to 21% if you were diving air?

There are both aggressive and conservative models on the market. With a previous one my wife used to get occasional skin-bends. Since we both moved to Suuntos some years ago we never had any more problems.

Some divers consider the more aggressive ones "better" because they get more bottom time but that's a twisted way of looking at it.

Dive safe.

 

[DocVikingo]

Advice from DAN suggested DCI on what was termed 'provocative dives'. I am now left feeling utterly confused as I have certainly dived much closer to deco limits without experiencing DCI; further, on all dives, more than 20 minutes spent at shallower depths (10-15m). I may not have drunk enough water before the second day's first dive as it occurred right after breakfast. Is it possible for divers to develop greater susceptibility to DCI? Or was this really a risky dive plan and combined with my lack of water intake a predictable result? My buddy was fine, as were other divers in the group.

Hi AmyKB,

Sorry to hear this.

Based on the description, you sustained a relatively worrisome Type II DCS hit. It was good fortune that your signs and symptoms completely resolved simply by extended administration of 02 with no recompression.

While the reported dive profiles certainly are not reckless, they are "provocative" in the sense that they are more than sufficient to generate an inert gas loading capable of precipitating an event of DCS. As for spending more than 20 minutes at shallower depths on all dives at issue, it must be kept in mind that one still is taking on N2 at depths of 10-15m.

The fact that in the past you have dived much closer to deco limits without experiencing DCI means relatively little as susceptibility to DCS can and does vary within the individual across dives. In some cases this susceptibility appears related to such factors as hydration status, while in others no potential causative factor can be identified. That your buddy was fine, as were other divers in the group, means nothing.

In future dives you'll want to be sure you remain very well hydrated, and perhaps dive slightly more conservative profiles.

If you sustain another such incident, it would be prudent to have a full SCUBA fitness work up, including assessment for PFO.

Best of luck.

Regards,

DocVikingo

This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual and should not be construed as such.

 

[redacted]

My computer advised me I ascended too quickly after the safety stop between 3m and surface on the last dive. ....

I may not have drunk enough water before the second day's first dive as it occurred right after breakfast.

If anyone has any input or insight or even if you've had a similar experience I'd be really happy to hear it

It is best if you do everything right to minimize the risk of DCS. Many divers get away with small transgressions. Looks like you did not. Even when everything is done right, you don't get a safety guarantee.

 

[TSandM]

The information about the rapid ascents at the end of the third dive is interesting. It's pretty common for people to be diligent about the "safety stop", but then just pop to the surface afterwards. If you think about it, the proportional pressure changes are greatest in that very shallow water, and for minimal bubble growth, one should take that part of the ascent as slowly as is safe in the conditions. (I realize that, where there is a lot of boat traffic, spending a lot of time between ten feet and the surface may be riskier than the low chance of DCS from surfacing faster.) I don't know that this is the responsible factor in your case, but it is interesting information.

 

[Doppler]

Even those of us who have experience planning decompression dives are confused by DCI so do not think you are missing anything; you are not.

DCI does not play fair. Even if you stick to the rules, it will always cheat and sometimes it will cheat a lot.

Recently had an acquaintance blow off more than 30 minutes of required decompression and get away with it.

Truth is that day-to-day, diver-to-diver there are no guarantees. The best we can do seems to be:
Maintain CV fitness
Maintain ascent rate (from safety stop to the surface, this means 3 metres per minute)
Dive well hydrated, well-rested, and under light workload
Dive within prescribed limits (80 percent of allowed time per depth is often suggested)
Avoid see-saw profiles and bounce dives
Use nitrox
Self-monitor during SI

 

[AmyKB]

What computer were you using?
Was it set to normal or conservative?
If it's a Nitrox model are you sure it was set to 21% if you were diving air?

Thanks for your input. I use a scubapro which I've heard is generally quite conservative. The log confirms it was set to air.

 

[AmyKB]

Thanks for the input everyone. It seems the reassurance, somewhat ironically lies in the fact that there are no guarantees!

I appreciate TSandM's reminder about slow ascents even at very shallow depths and the comments about the range of factors that may have contributed.

I have no doubt this experience will make me a more diligent & better diver!

It is testament to the Goodwill and comradeship of the dive community that I receive so many thoughtful responses within such a short period of time. Thanks everyone.

 

[Duke Dive Medicine]

Amy,
I'll echo what DocVikingo said about you being very fortunate that your symptoms resolved on O2, and add that you're even more fortunate that they didn't come back with a vengeance after you discontinued the oxygen. You appear to have had a pretty clear-cut case of decompression illness, and DCI should ALWAYS be treated in a hyperbaric chamber, even if you're completely asymptomatic after using surface oxygen.
Best regards,
DDM

 

[Rileybri]

Did you contact DAN about this? I am curois as to what their input was?