Quote: (Originally Posted by
Mark Chase)
The question is; Is NOT bailing out too big a gamble?
If the scrubber or a valve has failed, then stopping doing a dill flush and breathing isn't going to work. So you stop do a triple flush with an elevated breathing rate and when it builds up even further you think OK it will calm down in a min and you do another triple flush. Then it becomes uncontrollable and you attempt to bailout.
But at this point it could be too late in terms of available gas.
Whilst it goes against what I was taught in Mod3 My attitude is I carry enough gas to make a 40RMV work on a reducing SAC so why not use it?
Bail out first start heading for home and if you feel the need you could flush the unit and go back on once RMV is back to normal just to see if its fixed or if it rises again.
Personally if I suffered elevated breathing rates and going OC fixed it. Id stay OC and go home to fight another day.
I have lugged those damed tanks around for the last three years i might as well use them
ATB
Mark
Bailing out could be the fail safe way to get over a CO2 hit, but it is apparent that you could be opening yourself up to other problems, IMO. As discussed IBCD, oxtox.
What I have been tought (rightly or wrongly) is to dil flush in hyper/hypoxia scenarios and in a hypercapnia scenario. Without getting into the unit specifics, on the Meg a 2 second dil flush is enough to replenish the loop volume (or at least a good percentage of it) with fresh dil. So my protocol (Only my protocol, not something that I have been tought) is to dil flush, If this doesnt help then flip onto OC thro the BOV.
Quote: (Originally Posted by
Drmike)
I think if you are suffering from retained CO2 there wont be any CO2 in the loop (as the scrubber is working) only have CO2 in loop if you have scrubber failure (which isnt cause of retained CO2)
Of course, the dil flush will only work if it is CO2 retention, NOT in the case of a failed scrubber or mushroom valve. But if you have packed the scrubber properly, prebreathed properly and havent pushed the scrubber duration then surely the chances of scrubber failure are minimal?? Please correct me if I'm talking jibberish.
Quote: (Originally Posted by
Simon Mitchell)
This is not quite the full story, because oxygen carriage in the blood is altered by high CO2 (it shifts the oxygen - haemoglobin dissociation curve to the right), but this is a more complex bit of physiology, and it is still largely irrelevant to survival in the context of breathing elevated PO2s at depth.
Hope this helps.
Simon M
Ah ah, the dissasociation curve. That was what I was referring to in one of my earlier posts. All those years at uni weren't a complete waste of time for me then!!
Another interesting point you made Simon, was although CO2 elevation stimulates breathing, (rate and depth??) in vastly elevated CO2 scenarios it acts as an anaesthetic ultimately suppressing breathing. Another confusion I had cleared up. Cheers.
Many thanks to the posters on this thread. I've learned a lot. This is what this forum is all about IMO
