Emergency Ascent practices

[Se7en]

I was thinking along the lines that for most of us we are diving fairly well replicated procedures - ie diving using a computer / tables. While we follow the computer tables, we are unlikely to get bent, unless very unfit, dehydrated yada yada.

Therefore, it is most likely that if we were to bend, it would be as a result of missing deco, or having a forced rapid ascent rate etc. In these instances, being able to get onto the o2 before getting out of the water, would obviously be great. But then it is not really IWR, but rather deco.

Mike

 

[devjr]

Mike, sometimes it happens that there is no big mistake, just some small mistakes which were seemingly innocuous by themselves. Yes, dehydration, fatigue and cold were some of the little problems. However, the one which hit me was complacency.

The problem dive, which took place at 4 pm, was my only SCUBA dive of the day but it actually counted as a repetitive dive. The chamber physician explained that the freediving which I had done earlier that day probably placed me in Group C (?) even as I was entering the water for a 100' tank dive.

Of course I pushed the limits and didn't take a "safety" stop which middle aged folks like myself should do. My actual bottom time was about 25 minutes and I used 72 cf of air. Just lots of little things.

 

[pipedope]

If you are going to a place where no chamber is readily available and are bringing the people, equipment and supplies that would make good IWR possible, why not bring along a chamber?

I will accept that IWR is better than nothing but it is far more difficult and dangerous than treatment in a proper chamber.

Pardon my commercial bias but anytime working dives are going on that require deco a chamber is *on site*. Even if you could get by without one you could kiss your insurance goodby if you do deco diving (commercial)without a chamber available.

michael

 

[Dr Deco]

Dear Readers:

This is truly and interesting topic and no one really wishes to be a first hand participant. I do not have any laboratory experience with this type of treatment and therefore cannot give any personal experience. I, as a research scientist, could offer a few words however with respect to some of the replies give to date.

[sp] 1. It does not appear that gas bubbles on the venous side will arterialize through the lungs to the arterial circulation. This has been discussed before in this FORUM. It is based on evidence from Doppler ultrasound studies with laboratory animals.

[sp] 2. Observations on humans during altitude exposure have shown no problems with repressurization. Numerous individuals have demonstrated large numbers of Doppler bubbles (Grade IV on the Spence/Johanson scale) and have not given evidence that arterialization occurs with repressurization to site level. Additionally, there is not an exacerbation of DCS or the appearance of new presentations.

[sp] 3. Gas bubbles that are present in the circulatory system are cylindrical in geometry when they are occluding a channel. The increase of pressure will cause a reduction in volume and of length. The decrease in length will possibly lead to the unblocking of some portions of the arteriolar system. Further, the decrease in length will assist in the transcapillary passage of the free gas phase. In fact, the capillary system does not seem to retain gas bubbles except in the pulmonary system, which is designed to filter out debris such as blood clots.

Dr Deco
:doctor: