Quote:
| Originally Posted by milldog Plan A
this is the same dive but using 100% at the end if you count the run times then the 80% is better, it's also better later on once your out as the [1] calming effect isn't as bad.
adding to that you also encounter (if you get this wrong) Absorptive Atelectasis: Which occurs when high levels of O2 "washout" the Nitrogen in the alveoli, leading to collapse of these sacs (alveolar collapse = atelectasis) and decreased perfusion space leading to something called a shunt. Shunting is basically a mismatch between the sacs that should be filled with oxygen and the flow of blood around them. With collapse of airspace, improper diffusion of oxygen to the blood occurs, lung can become damaged, irreparably.
refrence above Dr Mark Sullivan and Gilbert, DL. Oxygen: An overall biological view
so whilst doing the airbreaks is good for the body and dependant if this is counted in the deco, over a few days diving this could lead to damage compounded over a few days and bend you!!
so this adds another part to the question would you over a five day dive trip adjust the air breaks for longer periods?
Graham
[1] calming effect after periods on pure O2 the body once breathing normal air will encounter a feeling of tiredness sometime's sever exhaustion due to the work the encountered on the body without N2 in the breathing air. |
The Absortive Atelectasis is only a concern with high pulomary toxicity due to continued long exposure to O2.
Apart from the high PPO2 on the bottom as And suggested I would use a max of 1.2 probably lower, as I would always assume I was working at depth - cold etc.
I would continue on multi-day exposures to run 12 on 6 off, and have done this on a regular basis. The whole CNS % measuring system is suspect to say the least, after all there are some out there who have dived exposures in excess of 1000% according to the measurements and are very much still with us.
The cycling mechanism seems to prevent most of the problems associated with Pulmonary Toxicity and CNS Tox.
Andy