Had a little scare this weekend

[Deefstes]

I'm not sure if this is the correct forum for this post as I'm not sure whether it really was a near miss and I'm not sure if I've learned a lesson. I hope the mods will move the thread if there is a better forum for it.

So on Saturday my wife and I did a dive at the local quarry. It was pretty cold by our standards (14 degrees celcius / 57F) and I was diving a 5mm full length wetsuit with a 3mm chicken vest underneath. The cold water didn't really bother me on the dive other than perhaps making my fingers a bit numb (and dumb).

The dive was to a max depth of 29m (95ft) and pretty much followed a square profile but with a fairly slow descent and ascent. Here is the profile, should it be of interest.
http://i74.photobucket.com/albums/i2...rd/profile.png

At the end of the dive (7min shy of NDL) I deployed a SMB. I wanted to practice deploying the SMB from depth but in open water so I hovered near a helicopter for visual reference but was not on the bottom or on the helicopter. I inflated the SMB slightly just to get it to stand upright and just as I gave it a full blast of air, a coil of the string slipped off the finger spool and caught around my thumb. The SMB yanked me upwards and I probably ascended 5m before I could untangle the string from my thumb.

This happened at 27m (I was pulled from 27m to 22m) and immediately after I untangled my thumb I swam down again, although from the profile I can see that I didn't swim down as much as I thought. I would like to believe that I did not hold my breath during the quick ascent but in honesty I can't really remember.

The rest of the ascent went without incident and we did a very slow ascent (3m/min) and a normal safety stop.

So that in itself doesn't seem all that dangerous. The rapid ascent occurred fairly deep (where the pressure differential isn't that great), it was only a 5m rapid ascent and I think I recovered fairly well afterwards. Provided I didn't hold my breath during this quick ascent I should think it doesn't have to be a big problem right?

So here is why I'm worried. These symptoms might of course be completely unrelated to the rapid ascent but I'd like to test your opinions. I think I'll see a doctor anyway just to get a professional opinion as well.

Not long after the dive I started feeling a slight sense of unease. It's hard to explain exactly what. I was just not hungry and there was an ever so slight discomfort in my chest. That night the discomfort grew to something more noticeable and it kept me awake. I had no shortness of breath or anything but I had a sensation of a dull pain inside my chest just below the left clavicle.

At one point during the night I got up and drank two aspirins after which the dull pain subsided fairly quickly and I could sleep. By the morning I had no such sensation anymore.

Like I said, this strange sensation might be completely unrelated to the sharp ascent. It might be related to the fact that my wetsuit (which is a little bit too small) plus the extra 3mm chicken vest were just too tight or it could be related to the fact that I had a couple too many chicken samosas after the dive. The fact that the dull pain was in my chest and that it subsided after I took two aspirins have me slightly worried that this could point to heart disease. I'm fairly young (35) but do have a history of heart disease in my family.

The more I'm typing the more I realise that it would probably be a good idea to go see a doctor. Either way, I'd be interested in your opinions.

[blkirk91]

See a DR, but also which hand did the string wrap around? the pull of the SMB might have strained a muscle with out you realizing it.

[Solly]

did you notice any unusual coughing when you got up in the morning?
sometimes when the regulator breathes wet, some water droplets get to the lungs causing a feeling of unease in the chest, pain and sometimes fever which all goes by a couple of aspirin pills and after wakeup coughing might occur .... when this occurs on a day dive, symptoms appear after a while, mostly in the evening....
Seeing a doctor is a good idea, but exploring all alternatives is needed as well ...

Dive safe

[stairman]

I wouldnt see a doctor if the slight pain was gone and I felt fine. However, I would see one for a physical to rule out any underlying issues that may surface before you do.

[Sinbad Scuba]

I agree seeing a doctor is a good idea. It could also be pain driven by stress and concern about having a pain. Relax. See a Doctor, probably get a chest X-ray.
Question: why did you want to deploy an SMB from such a depth? Doing anything at depth is harder and inherently carries more risk. You also might look into buying an SMB that comes with the 6 meters of flat line.
Dive safe.

[Deefstes]

Question: why did you want to deploy an SMB from such a depth? Doing anything at depth is harder and inherently carries more risk.

Because I wanted to practice the skill. I also regularly practice deploying from shallow depth and I thought it was time to practice deploying from deeper depth again. I think this little mishap illustrates exactly why it is necessary to practice this.

It is true that most exercises are easier at shallower depths but in some ways I actually prefer deploying a SMB from deeper.
- You only need a small amount of air in the SMB for it to inflate fully at the surface.
- Controlling your buoyancy is easier at depth than in shallower water.
- I'd much rather be yanked from 27m to 22m than from 5m to the surface.

That said, I usually deploy from around 10m, not 27m. For me, that is sort of a nice middle ground.

[koyote1111]

I recommend seeing a doctor. If anything, it may ease your concerns. I've had an experience with DCI and asked a lot of questions in the process of my visits to the chamber. I was told that it is very common for people to find other reasons for the symptoms that they are experiencing. I did the same...thought I had perhaps tightened in my BCD a bit too much, perhaps the swimsuit had caused the rash, etc. A day later, I knew these ideas were not true.
I sure hope that you are ok...however, there is certainly no harm in seeing a physician.

[spectrum]

I'd much rather be yanked from 27m to 22m than from 5m to the surface.

Is this true for lung expansion risk? In either case you are creating a pressure differential equal to X FSW if breath is held. I'm not saying you did. The air in your lungs as provided by your second stage is equal to ambient pressure.

This is contrasted to something like neoprene compression where the gas content of the rubber is absolute and we're talking about % change in compression. BC bladder air is also in this category.

I don't mean to hijack here but I wouldn't want others to get the wrong idea. Am I on the right track?

A call to DAN or a visit to the doctor can never hurt. In this case where the symptoms were gone in short order I'd be inclined to pass. It could be a combination of you getting a little rattled by the incident and that tight suit. Some sort of hypertension or strain while reacting is not to be overlooked either.

I did have a suit once that was tight enough in the chest to stress the rib cage. It only got used for skin diving but after a few uses left my ribs sore a for a week or 2.

Pete

[Deefstes]

Is this true for lung expansion risk? In either case you are creating a pressure differential equal to X FSW if breath is held. I'm not saying you did. The air in your lungs as provided by your second stage is equal to ambient pressure.

You can't just measure pressure differential in terms of x FSW. The pressure differential from 30m to 25m is far less than the pressure differential from 5m to 0m. Let me put it this way, according to Boyle's law: p*V=k where p denotes pressure, V denotes volume and k denotes the pressure constant.

So, let's say I inhale fully and close off my air passages. Assuming my lungs have a capacity of 6 liter. If I fill them up at 30m and then ascend to 25m the new volume of my lungs can be calculated as follows:
p1*V1 = p2*V2 where p1 denotes pressure at 30m, V1 denotes volume at 30m, p2 denotes pressure at 25m and V2 denotes volume at 25m.
so 4*6 = 3.5*V2
so V2 = 4*6/3.5 = 6.86 liters
That's an expansion of 0.86 liters or a 14% increase in volume. Not good but probably not disastrous, at least not when compared to filling up my lungs at 5m and then ascend to 0m:
p1*V1 = p2*V2
so 1.5*6 = 1*V2
so V2 = 1.5*6 = 9 liters
That's an expansion of 3 liters or a 50% increase in volume. I definitely prefer option A.

To put it simply, the pressure differential is not a function of depth 1 minus depth 2 but rather of pressure 1 divided by pressure 2. As you can see above, this is much more pronounced at shallower depths.

[spectrum]

I need to quit thinking physics before and after bedtime......